I
Extractability of drug traces and metabolites from water media by
polyurethane foam and block copolymer membranes
Der Fakultät für Naturwissenschaften
Department Chemie
der Universität Paderborn
Zur Erlangung des Grades eines
Doktors der Naturwissenschaften
Dr. rer. nat.
Vorgelegte Dissertation
Von
Intisar A. F. EL- Sharaa, M.Sc. in Chemistry
aus Benghazi/Libyen
Paderborn 2010
II
The present work has been carried out from May 2005 until December 2009 at the
University of Paderborn, Faculty of Science, Department of Chemistry under
supervision of Prof. Dr. M. Grote.
Referent Prof. Dr. Manfred Grote
Koreferent Prof. Dr. Wolfgang Bremser
Eingereicht am 04.05.2010
Tag der mündlichen Prüfung: 26.05.2010
III
Aknowledgements
First of all, I would like to express my deepest sense of gratitude to my supervisor,
Prof. Dr. Manfred Grote, for his patient guidance, encouragement and advice
throughout this study.
I would also like to thank Prof. Dr. Wolfgang Bremser for scientific support, and his
coworker Dr. Björn Weber for synthesizing polymer membranes which were used in
this study.
I am thankful to my laboratory members, Dr. Nabil Al. Hadithi, Dipl. Chem- Ing.
Didem Hanim Meric, Dipl. Chem- Ing. Reinhard Michel, Dipl- Chem. Manuel Ewe,
Dipl- Chem. Mareike Busse, Staatl. Gepr. LM Chem. Farzana Chowdhury and Mrs.
R. Knaup for creating an environment comfortable working and welcoming me at the
university making me feel at home, and teaching me some German culture. It is truly
an honor for me to know each and everyone.
Special thanks to Reinhard and Manuel for sharing with me a lot invaluable
knowledge regarding instrument operation methods and, which will be very helpful
and useful for my future scientific live.
I would also like to thank Dr. Ishtiaq Ahmed, and Dr. Nabil Bader for proof-reading my
thesis and providing valuable feedback.
I deeply thank my true and faithful friends Khawla Franka, Fhatiha Ouazir, Ainas
ELshara, Aziza Ahmida, Sheelan Khasro and encouragement from all of my friends.
My sincere thanks go to the Yesilyurt and Gürbüz families for helping me and they
are really a family to me in this country.
I thank the Secretariat of higher education of Libya for giving me Ph.D. scholarship.
Finally, I extend my warmest thanks to my wonderful big family for being a source of
inspiration and continuously encouragement in all my life directions.
First and foremost, I would like to thank God for giving me this chance, and this
paves the way for a prolific scientific career.
Intisar EL-Sharaa
01.05.2010
IV
Dad’s spirit and Mum,
My Family,
My relatives and friends.
V
Table of Contents
1
Pharmaceuticals in the aquatic environment
4
1.1 Sources and origins
8
1.2 Fate of drugs after medical application 9
1.3 How do the drugs get into the water? 10
1.4 Possible effects on the environment 12
2 Aim of the study 14
3 Pharmaceuticals used in this study: basic properties 17
3.1 Antibiotics 17
3.2 Use of antibiotics 17
3.3 Antibacterial resistance and the environment
18
3.4 Tetracyclines 20
3.4.1 Tetracycline (TC) 20
3.4.1.1 Characterization 20
3.4.1.2 Environmental behaviour 21
3.4.2 Chlortetracycline (CTC) 22
3.4.2.1 Environmental behaviour 22
3.5 Sulfonamides 23
3.5.1 Sulfamethoxazole (SFM) 23
3.5.1.1 Metabolism 24
3.5.1.2 Environmental effects 25
3.6 Neuroactive compounds ( antiepileptic, antidepressants )-
Carbamazepine (CBZ)
27
3.6.1 Metabolism 28
3.6.2 Environmental behaviour 28
3.6.3 Environment effects 29
3.7 Analgesics and ant-inflammatory drugs 30
3.7.1 Diclofenac (DCF) 30
3.7.1.1 Metabolism 30
3.7.1.2 Environmental behaviour 31
3.7.1.3 Environmental effects 32
3.7.2 Ibuprofen (IBU) 32
3.7.2.1 Metabolism 32
VI
3.7.2.2 Environmental behaviour 33
3.7.2.3 Environmental effects 33
4 Analytical extraction techniques 34
4.1 Principle of polymeric membrane 36
4.1.1 Polymeric membrane extraction (PME) 36
4.1.2 Diffusion in polymers 37
5 Polyurethane Foam (PUF) as a sorbent in analytical chemistry
38
5.1 Fundamental chemistry of polyurethane foam 38
5.2 Polyurethane foam: The sorbent material 39
5.3 Polyurethane foam preparation 40
5.3.1 Physical and chemical properties of polyurethane foam 41
5.3.2 Option for separations using polyurethane foam membranes 43
5.4 Mechanistic approaches to the sorption processes on PUF 44
5.5 PUF as sorption Techniques from aqueous media 44
5.6 Using polyurethane foam for removal of organic contaminants 45
6 Novel blockcopolymers 50
6.1 Synthesis and structure of membranes 50
6.1 Novel polymeric membrane based on diphenylen 50
6.1.2 Composition of polymer membrane foam 52
7 Results and discussion – polyurethane foam 53
7.1
7.1.1
Methodical approach
Chromatographic methods
53
53
7.2 Extraction of the drugs and metabolites by PUF 54
7.2.1 Materials and methods 54
7.2.2 Polyurethane types used 54
7.3 Extractability of N-4-acetylsulfamethoxazole (ASFM), SFM and
CBZ by PUF
56
7.3.1 Sorption of ASFM- Effect of shaking time and PUF- type 57
7.3.2 Effect of pH on the sorption 59
7.3.3 Effect of salts on the sorption 64
7.3.4 Recovery process of drugs from loaded PUF 65
7.4 Sorption of Tetracyclines (TCs) by PUF 70
7.4.1 Influence of pH media on the sorption of TCs by PUF 70
VII
8 Sorption of drugs by novel polymeric membranes (BM) 74
8.1 Extractability of polymer membranes for SFM, CBZ, DCF and
IBU
74
8.2 Extraction of tetracyclines drugs by novel polymer membranes 78
8.3 Effect of pH on the sorption by polymeric membrane 81
8.3.1 Active drugs SFM, CBZ, DCF and IBU 81
8.3.2 Influence of pH on the sorption of TCs 82
8.4 Recovery of TCs drugs from loaded BM34 and BM43 polymers 85
8.4.1 Extraction from acidic media 85
8.4.2 Recovery of the drugs loaded on BM34 and BM43 polymers 87
9 Results and Discussion – Comparative discussion 92
9.1 Comparative study between the extraction and elution behaviour
of PUF and BM
92
9.2 Comparative study of extraction by polymer membranes and
other extraction techniques
94
10 Summary 96
11 Experimental 99
12 References 114
I
List of Figures
Fig. 1.1 EU-wide veterinary medicine in the drug groups established in
2006
5
Fig. 1.2 Sources and distribution of pharmaceuticals in the environment 11
Fig. 3.1 Major pathways of the oxidative metabolism of SFM in human 24
Fig. 3.2 Major pathways of the oxidative metabolism of CBZ in human 28
Fig. 3.3 Major oxidative metabolism products of DCF in urine 31
Fig. 3.4 Major pathways of the oxidative metabolism of IBU in human 33
Fig. 5.1 Scanning electron micrograph of typical polyurethane foam
structure
39
Fig. 6.1 Scanning electron-micrographs of a typical BM structure and
layer structure of polymer membrane
52
Fig. 6.2 Monomers of polymer membrane compounds investigated 52
Fig. 7.1 Calibration curve of target drugs (CBZ, SFM and metabolite
ASFM)
56
Fig. 7.2 Effect of PUF types on sorption of ASFM 58
Fig. 7.3 Influence of pH on the extraction of target compounds by PUF
(CBZ, SFM and ASFM)
61
Fig. 7.4 Effect of pH on the sorption of drugs by PUF
61
Fig. 7.5 Influence of salts on target drug extraction at pH 3 64
Fig. 7.6 Size effect of ionic radii of various metal cations on the sorption
of ASFM
65
Fig. 7.7 Extraction and recovery procedures by meansPUF
66
Fig. 7.8 Influence of shaking time on the recovery of target drugs from
PUF loaded with various eluting agents
67
Fig. 7.9 Extraction and recovery of drugs with different solvent from PUF
67
II
Fig. 7.10 Effect of pH and time on extraction of TCs drugs by PUF 72
Fig. 7.11 Effect of pH on extraction of tetracycline’s 72
Fig. 8.1 Monomers used for the synthesis of novel block copolymer
membrane compounds
75
Fig. 8.2 Extraction of drugs by polymer membranes as a function of
time
77
Fig. 8.3 Comparison of the extractability of active drugs by BM42 and
BM43
78
Fig. 8.4 Extractability of TCs polymer membranes as a function of time 80
Fig. 8.5 Extraction of active drugs at pH 3 and by polymers BM42 and
BM43 as function of time
81
Fig. 8.6 Influence of pH on the extraction of drugs by polymer
membranes
82
Fig. 8.7 Extraction of TCs drugs at pH 3 by polymer membranes BM42,
BM 43 and 34
84
Fig. 8.8 Influence of pH on extraction of TCs drugs by BM43 85
Fig. 8.9 Extraction of target active drugs at pH 3 by selected polymer
membranes (BM43 and BM34)
87
Fig. 8.10 Recovery of drugs from loaded BM34 with acetone and
acetonitrile as function of time
89
Fig. 8.11 Recovery of drugs from loaded BM43 with acetone and
acetonitrile as function of time
89
Fig. 8.12 Comparison of recovery processes for both MB34 and BM43
Polymeric membrane with different eluting agents
90
Fig. 9.1 Comparison of extractability of selected drugs by PUF and BM
membranes 93
Fig. 9.2 Comparison between BM34 and BM43 polymer membranes
94
Fig. 11.1 Purification of PUF foam, a) acetone after foams treatment, b)
pure acetone
101
Fig. 11.2 HPLC-UV chromatogram:blank sample of BM34 102
III
Fig. 11.3 HPLC-UV chromatogram for the selected drug metabolite and
active drugs by using different methods
111
IV
List of Tables
Tab. 1.1 Consumption amounts of selected drugs in various countries 5
Tab. 1.2 Survey of the concentrations of target pharmaceuticals detected
in sewage water (ng/L) in various countries
6
Tab. 1.3 Survey of the concentrations of target pharmaceuticals detected
(ng/L) in different water sources
10
Tab. 1.4 Summary of concentration of target drugs in Rivers and Lakes
in various countries by µg/L
12
Tab. 2.1 Structure of selected pharmaceuticals 15
Tab. 2.2 Basic properties
of selected pharmaceuticals (pk
a
and log P
values) at 25
o
C
16
Tab. 3.1 Active drugs under study: basic properties and ecotoxicological
data
26
Tab. 4.1 Different major membrane techniques used in analytical
application
35
Tab. 5.1 Separations from liquid phases using treated and untreated
polyurethane foam (PUF) membranes
46
Tab. 7.1 Types of selected Polyurethane Foams in total volume of 10 mL 55
Tab. 7.2 Standard solutions of target drugs 55
Tab. 7.3 Effect of PUF types and equilibrium time on sorption of ASFM 58
Tab. 7.4 Influence of pH on and extraction time sorption of selected
drugs
60
Tab. 7.5 Loaded amounts on PUF at pH 3 65
Tab. 7.6 Recovery percentage of target drugs from PUF cubes with
various eluent
66
Tab. 7.7 Amounts of target drugs eluted from loaded PUF cubes 68
Tab. 7.8 Total mass of target drugs extracted and recovery 68
Tab. 8.1 Optimum extraction yields for drugs obtained by polymer
membranes in water
76
Tab. 8.2 Extraction data at optimum conditions for polymer membranes
in water
76
Tab. 8.3 Extraction percentage of target drugs from water by polymer
membranes as function of time
79
V
Tab. 8.4 Total masses of target drugs determined in extraction
processes by polymer membranes
79
Tab. 8.5 Optimum extraction values of drugs obtained by BM42 and
BM43
81
Tab. 8.6 Optimum extraction values of TCs obtained 83
Tab. 8.7 Total mass of TCs by membrane BM43 85
Tab. 8.8 Total masses of target drugs determined by extraction
processes with polymers
86
Tab. 8.9 Amounts of target drugs eluted from loaded BM34 and BM43
cubes by acetone and acetonitrile
88
Tab. 8.10 Maximum recovery percentage of target drugs with BM34 and
BM43 by acetone and acetonitrile as eluents
88
Tab. 9.1
Comparison of the extractability of drugs by PUF and polymeric
membranes
92
Tab. 9.2 Comparison of recoveries obtained with PUF and polymeric
membranes
93
Tab. 11.1 Impuirites in blank samples of polymer membranes detected by
HPLC- UV
102
Tab. 11.2 Chemicals used in this work 106
Tab. 11.3 Materials used in this work 107
Tab. 11.4 Equipments used in this work 107
Tab. 11.5
1
H-NMR-data 112
Tab. 11.6
13
C-NMR-data 112
I
List of abbreviations and acronyms
aq aqueous phase
AN acrylonitrile
ASFM N-4-acetylsulfamethoxazole
BM Novel synthesized polymeric membrane
CAFOs confined feeding operations
CAS chemical abstracts service
CBZ carbamazepine
C. dubia Ceriodaphnia dubia
CRP controlled radical polymerization
CTC chlortetracycline
D distribution ratio
d day
DCF diclofenac
DDDs defined daily doses
DHTC dihydroxytetracycline
DMSO dimethylsulphoxide
DNA desoxyribonucleic acid
DPE diphenylethylene
DS dry substance
DW drinking water
%E extraction percentage of analytes
EC
50
molar concentration of an agonist, which produces 50% of the
maximum possible response for that agonist
ESI Electrospray ionisation
Ep-CBZ
F.R
10,11-epoxycarbamazepine
flow rate
GW ground water
HAc acetic acid
HPLC high performance liquid chromatography
IBU ibuprofen
II
iso-CTC iso-chlortetracycline
K
F
partition coefficient of the analyte between feed and membrane
phase
kg
K
oc
kilogram
dissocation constant
K
ow
partition coefficient n-octanol-water
LC-MS Liquid chromatography- Mass spectrometer/spectrometry
liq liquid phase
LLE liquid-liquid extraction
LOEC lowest observed effect concentration
log P partition coefficient
MA methylacrylate
MAN methacrylonitrile
mg milligram
µg microgram
min minute
mL millilitre
Mm
MW
molecular mass
molecular weight (g/mol)
MMA methylmethacrylate
MMLLE micro-porous membrane liquid-liquid extraction
mol mole
M.p Melting point
MRI magnetic resonance imaging
n number of samples
n.a. not available
n.d. not detected
ng nanogram
nm nanometer
NOEC no observed effect concentration
NSAID non-steroidal anti-inflammatory drugs
OECD Organisation for Economic cooperation and Development
org organic phase
III
PEC
sw
predicted environmental concentrations for surface water
pKa negative logarithm of the dissociation constant
PME polymeric membrane extraction
PUF
r
polyurethane foam
round
R
t
retention time
SFM sulfamethoxazole
SPE solid phase extraction
STP sewage treatment plant
SW surface water
β
o
initial concentration (mg/L)
β
s
Concentration of solution after sorption (mg/L)
t ton
TC tetracycline
TCs tetracyclines
TDi toluene diisocyanate
t
E
equilibrium time of extraction experiment
t
R
equilibrium time of recovery experiment
TW tap water
UV ultra violet
V volume (mL)
v/v volume/volume
V
E
volume of extraction from aqueous solution
V
R
volume of recovery of elution
V
S
volume of sample
vs Versus
ג
Wave lenght
W
F
weight of membrane foam
WWTP wastewater treatment plant
4
1 Pharmaceuticals in the aquatic environment
If we look at environmental history, we can realize that the issue of pharmaceuticals
and their metabolites in the aquatic environment has raised increasing concern in
recent years. Many of the more commonly used drug groups, for example antibiotics,
anti-epileptics and anti-analgesics, are used in quantities similar to those of many
agrochemicals and other organic micro pollutants but they are not required to
undergo the same level of testing for possible environmental effects [1]. The
consumption quantities of these pharmaceuticals are increasing day after day. For
example in Germany, the estimated amount of carbamazepine (CBZ), used in 1998
was 74 t. In 2001 the amount increased to 87.6 t. In 2005 this amount increased
dramatically to over 100 t [2]. Table 1.1 listed below shows how many kilograms of
the specific drugs are used each year as human medicine in certain countries.
Figure 1.1 shows the consumption of veterinary drugs in Germany in 1997 [3]. The
extent and consequences of the presence of these compounds in the environment
are therefore largely unknown and it is entirely an ill-defined issue, although these
compounds have been detected in many countries in sewage treatment plants (STP)
effluents, surface waters, seawaters, groundwater and drinking waters. Table 1.2
shows concentration levels for wastewater.
For some pharmaceuticals, the effects on aquatic organisms have been investigated
in acute toxicity assays. The chronic toxicity and potential subtle effects are only
marginally known [4]. The pharmaceuticals and their metabolites have therefore been
subjected to many years of unrestricted emission to the environment in the form of
complex mixtures via a number of pathways, primarily from sewage treatment plant
(STP) effluents or sludge [5]. There has been periodic interest concerning the subject
of pharmaceuticals in the environment in previous decades [6-8].
The first report on pharmaceuticals in wastewater effluents and surface waters was
published in the United States in the 1970s [9]. Pharmaceuticals as environmental
Plants and animals know better
how to live than man; nobody can be in
good health, If he does not have all the
time fresh air, sunshine and good water.
Flying Hawk
contaminants did not receive a great deal of attention until the link was established
between a synthetic birth-
control pharmaceutical and impacts on environment.
Table
1.1:
Consumption amounts of selected drugs in various countries (kg/year)
a
Germany 2007 [2],
b
UK 2008 [15],
DCF: Diclofe
nac, IBU: Ibuprofen, SFM: Sulfamethoxazole, TC: Tetracycline, CTC: Chlortetracycline
Figure1.1: EU-
wide veterinary medicine in the drug groups established in 2006
46%
Drugs
PEC
µg/L
Quantities of drugs (human pharmaceutical) cons
Germany
1995
[10]
CBZ
1.23 80.000
DCF
0.80 75.000
IBU
4.96 105.000
424.880
SFM
- 13.166
a
TC
- 39.852
a
14.07
CTC
- 3.347
d
24.130
contaminants did not receive a great deal of attention until the link was established
control pharmaceutical and impacts on environment.
Consumption amounts of selected drugs in various countries (kg/year)
UK 2008 [15],
c
Denmark 2000 [16],
d
Germany 2002 [17], CBZ: Carbamazepine,
nac, IBU: Ibuprofen, SFM: Sulfamethoxazole, TC: Tetracycline, CTC: Chlortetracycline
wide veterinary medicine in the drug groups established in 2006
12%
26%
5%
6%
5%
Sulfonamides 98 t
ß-
Lactames 199 t
Aminoglycosides 36 t
Makrolides 53 t
Tetracyclines 350 t
other 36 t
Quantities of drugs (human pharmaceutical) cons
umed (kg/year)
Germany
UK [12]
Austria
2003 [13]
2001
[11]
2000
2002
87.600 2.256.000 40.348.75
633.4
85.800 7.639.000 26.120.53
614.3
424.880
6.683.000 162.209.06
669.6
53.600 622.000 46.430.43
b
963
14.07
d
- - -
24.130
d
- - -
5
contaminants did not receive a great deal of attention until the link was established
control pharmaceutical and impacts on environment.
Consumption amounts of selected drugs in various countries (kg/year)
Germany 2002 [17], CBZ: Carbamazepine,
nac, IBU: Ibuprofen, SFM: Sulfamethoxazole, TC: Tetracycline, CTC: Chlortetracycline
wide veterinary medicine in the drug groups established in 2006
[26]
Sulfonamides 98 t
Lactames 199 t
Aminoglycosides 36 t
Makrolides 53 t
Tetracyclines 350 t
umed (kg/year)
Austria
2003 [13]
Denmark
2007 [14]
633.4
87.605
614.3
85.801
669.6
33.792
c
963
58.407
1.954
-
6
Table
1.2: Survey of the concentrations of target pharmaceuticals detected in
sewage water (ng/L) in various countries as reported in publicly
available literature
Drugs
Finland
2007 [18]
Sou
th
Korean
2007 [19]
Denmark
2007-2008
[14]
Switzerland
2003 [20]
Berlin,
Germany
2002 [21]
Sweden
1999
[22,41]
STPi
STPe
STPi
STPe
STPi
STPe
STPi
STPe
STPi
STPe
STPe
CBZ
820 2440 42 729 120 1100 - 950 1780 1630
6300
d
1100
DCF
850 - 10 127 93 1200 - 990 3020 2510 1200
IBU
850 - 5320 137 530
711 7110
c
1300 5700 180 530
711
SFM
1600
a
- 194 407 82 480 - - - 900
370
e
480
TC
- - - - 22 - - - - 20
f
-
CTC
- - - - 3 - - - - 10
f
-
STPe: sewage treatment plants effluents, STPi: sewage treatment plants influents
a
USA, 2004, Ref. [23],
b
Denmark, 2000, Ref. [16],
c
Sweden, 2002, Ref [24],
d
Germany, 1996-1998,
Ref. [25],
e
Germany, 2006, [26],
f
Germany, 2002, [17]
However, in the past this interest has not been reflected in the amount of scientific
investigation actually carried out. In recent years, more and more positive results for
pharmaceutical substances or metabolites in different types of water have been
reported. For example, on 9
th
March 2008, a vast array of pharmaceuticals have
been found, including antibiotics, anti-convulsants, mood stabilizers (CBZ) and sex
hormones, in the drinking water supplies of at least 41 million Americans, as shown
by an Associated Press (AP) investigation [8].
The concentrations of these pharmaceuticals are tiny, measured in quantities of parts
per billion or trillion, far below typical medical dosage levels. In any case, utility
companies insist that their water is perfectly safe.
But the presence of so many prescription drugs and over-the-counter medicines like
acetaminophen and ibuprofen in so much of our drinking water is heightening worries
among scientists of long-term consequences to human health. In the course of a five-
month inquiry, the AP discovered that these kinds of drugs have been detected in the
drinking water supplies of 24 major metropolitan areas-from Southern California to
Northern New Jersey, from Detroit to Louisville, Ky [8].
7
In effluents from sewage plants, pharmaceuticals are often found in concentrations of
up to 20 µg/L [27]. Depending on the rate of dilution, concentrations 100 ng/L up to1
µg/L are usually detected in river waters [28]. In these waters, the concentrations of
pharmaceuticals are about one order of magnitude less than in surface waters.
A great deal of interest has been generated in recent years with regard to the
environmental fate and behavior of pharmaceutical drugs. This has been prompted
by many industrialized countries newly discovering drug products in water resources
often used for drinking water and realizing the lack of or inadequacy of research
knowledge. A few studies have been published [29].
Aquatic toxicity risk assessment has been recently started by different working
groups, but for most of the relevant substances only a few toxicity data are available
[22]. In Germany a first thorough survey of pharmaceuticals in waters was elaborated
by a working group in the Ministry of the Environment in 1998 [30].
Pharmaceuticals and their metabolites are continually infused into the environment
via sewage treatment facilities and wet weather runoff. In many instances, untreated
sewage is discharged into receiving waters (e.g., flood overload events, domestic
‘’straight-piping’’ or sewage waters lacking municipal treatment). In the United States,
possibly more than a million homes do not have sewage systems but instead rely on
direct discharge of raw sewage into streams by straight-piping by outhouses not
connected to leach fields [27]. A number of Canadian cities are reported to discharge
3.25 billion liters per day (over 1 trillion liters per years) of essentially untreated
sewage into surface waters and the ocean [31]. Raw/treated sewage is also disposed
of from some locales in the deep ocean where it may reach upper waters.
Although little is known about the occurrence and effects of pharmaceuticals in the
environment, more data exist for antibiotics than for any other therapeutic class. This
is a result of their extensive use in human therapy and animal husbandry, their more
easily detected effects end points (e.g., via microbial and immunoassays), and their
greater chances of introduction into the environment. Pathways into the environment
include not just sewage treatment plants, but also by run-off and groundwater
contamination, especially from confined feeding operations (CAFOs). The literature
on antibiotics is much more developed because of the obvious issues of direct effects
on native microbiota (and consequent alteration of microbial community structure)
and development of resistance in potential human pathogens [32].
8
1.1 Sources and Origins
The possibility that pharmaceuticals can enter the environment from a number of
different routes and possibly cause untoward effects in biota has been noted in the
scientific literature for several decades, but its significance has gone largely
unnoticed. This probably results in a large part from the international regulation of
drugs by human health agencies, which usually have limited expertise in
environmental issues. Traditionally, drugs were rarely viewed as potential
environmental pollutants. There was seldom serious consideration as to their fates
once they were excreted from the user. Until the 1990s, any concerted efforts to look
for drugs in the environment would have been met with limited success because the
requisite chemical analysis tools were not commonly available. Tools needed a high
separator efficiency, to resolve the drugs from the plethora of other substances native
and anthropogenic alike, and have a low detection threshold (i.e., nanograms per liter
or parts per trillion). Other obstacles (which still exist in a large degree) such as many
pharmaceuticals and cosmetic ingredients and their metabolites are not available in
most common environmentally oriented mass spectral libraries.
Drugs in the environment did not capture the attention of the scientific or popular
press until the last couple of years, with some significant overviews/reviews
presented by S
Ø
rensoen et al. [33].
Although pharmaceuticals are used in large quantities in modern society, their
potential to reach surface waters and their impact on the environment have received
little attention during the last three decades. However, since the 1980s, some
investigations have been carried out on the occurrence fate of pharmaceuticals in the
environment [34]. The majority of these field investigations focused on the
determination of concentration levels of specific compounds in various compartments
of the aquatic environment. Detectable concentrations of drugs or of their metabolites
have then been reported in wastewater treatment plant (WWTP), effluents and
natural waters [35-37]. The occurrence of selected pharmaceuticals was also
reported in the Tyne estuary in the U.K. with concentrations ranging from 4 to 2972
ng/L [38]. Tables 2 and 3 give a summary on the concentrations of the most
frequently assessed pharmaceuticals in wastewater and surface water reported so
far for selected number countries. In rivers, lakes and seawaters, concentrations are
reported in the unit ng/L range [39, 40]. The rather persistent antiepileptic
9
carbamazepine has been detected with few exceptions in STP effluents, freshwater
(rivers and lakes) and even in seawater [41]. In surface water, sulfamethoxazole is
found with maximal concentrations 6 µg/L [42]. Carbamazepine contamination is
widespread. In 44 rivers across the USA, average levels were 90 ng/L in water and
4.2 ng/mg in the sediment [43]. Frequently, the analgesic ibuprofen and its
metabolites were detected in STP effluents, in surface water and see water of up to 1
µg/L [36, 44]. In Wisconsin, USA, 21 antibiotic compounds were detected in
wastewater in range ≤ 1.3 µg/L [45]. Table 1.3 shows concentration levels of
pharmaceutical compounds in surface and drinking waters.
1.2 Fate of drugs after medical application
The fate of the drugs from medical applications should be evaluated because the
metabolism can lead to the production of new and possibly more toxic species [46].
Drug metabolites have special importance as environmental pollutants because they
are known to be the main excretion products of most active pharmaceuticals. Little
data is known in literature concerning the fate and effects of the drugs after the
medication.
To answer the question for the fate of the drugs, we have to consider different
pathways. First, in the human, the major route in human metabolism results in a
series of compounds in varying concentrations [47]. Other drugs have one or two
major metabolic pathways that dominate their metabolism, but several minor
pathways can produce at least a metabolite too. After ingestion, most drugs undergo
substance-specific metabolization distinguished between phase I and phase II
metabolites. Phase I reactions usually include oxidation, reduction or hydrolysis and
the products are often more reactive and sometimes more toxic than the respective
parent compounds [48]. Phase II reactions involve conjugation mainly with glucuronic
or sulfuric acid, but also with acetic acid, glutathione. Both phase I and II
metabolization render the parent compound more water soluble [49]. While phase I
metabolites may also possess a pharmacological activity that is sometimes even
higher than that of the parent drug [50], phase II metabolites are usually inactive.
During sewage treatment and in manure, cleavage of the conjugate was observed
[51]. Secondly in water environments, the degradation might be caused by enzymatic
activities, hydrolysis or photo degradation. Another possibility for the metabolism
10
could happen during the biological treatment in the STP induced by biodegradation
as described in pilot systems for IBU by Kolpin et al. [52].
Table 1.3: Survey of the concentrations of target pharmaceuticals detected (ng/L) in
different water sources as reported in literature
Waters
CBZ
DCF
IBU
SFM
TC
CTC
References
Ruhr River
2006
290 107 169 229, 316 - - [53]
Denmark
2007-
2008
SW
786 820 - 678 254 262
[14]
GW
531 459 - 245 48 58
TW
12 56 - 1 0 0
Isar
Munich
2000
234 180 237 133 - - [54]
2002
628 660 - - - -
Zurich water
Lake
236 370 - - - - [55, 61]
Rhein River
2001
500, 1075 6
a
3
a
- 20
b
20
b
[56, 62]
Windsor
Canda,2006,
DW
80 30 - - - - [56]
River UK, 2006
- - 3080 - - - [57]
Tyne, River
UK, 2005
- 1036 2972 20 - - [38]
South Korean
2007
SW 61 7 38 36 - - [19]
DW - - 8 23 - -
Wells water,
Berlin,Germany
1999
99, 360 380 200 - - - [22, 58]
2001
470, 900
c
135, 590
c
- 410
d
- - [59]
Austria Upper,
River 2001
26.4 36 - - - - [60]
DW: drinking water, GW: ground water, SW: surface water and TW: tap water
a
Ref. [59],
b
Ref. [60],
c,d
Ref. [61, 62]
1.3 How do the drugs get into the water?
To date, residues of more than 100 different pharmaceuticals have been detected in
municipal sewage world-wide and in several samples of surface, ground, and in a few
cases even in drinking water [65-67]. For the most part, such residues are entering
the receiving surface waters by discharges from sewage treatment plants but there
are also several other potential sources (see figure 1.2).
Figure 1.2:
Sources and distribution of pharmaceuticals in the environment (
according to
M. Grote, unpublished
People take pills. Their bodies absorb some of the medication and many even
become inactive but many others particularly those excreted renal or not absorbed
fully from the gut can leave the body in their
indicates that as a result of wide range of pharmaceuticals, metabolites and their
conjugates are excreted into the sewage system. The wastewater is treated before it
is discharged into reservoirs, river or lakes. The
again at drinking water treatment plants and piped to consumers, but most of the
treatments do not remove all drug residues. Researchers do not yet understand the
exact risks from decades of persistent exposure to random co
levels of pharmaceuticals. Recent studies, which have gone virtually unnoticed by the
general public; have found alarming effects on human cells and wildlife
After application, pharmaceuticals are excreted and transported with the w
to sewage plants. Most of these substances are not biologically eliminated or
adsorbed to sewage sludge so that they reach the aquatic environment. Veterinary
drugs or pharmacological food additives are spread by dry or liquid manure to fields
Sources and distribution of pharmaceuticals in the environment (
M. Grote, unpublished
)
People take pills. Their bodies absorb some of the medication and many even
become inactive but many others particularly those excreted renal or not absorbed
fully from the gut can leave the body in their
active forms [72].
Present knowledge
indicates that as a result of wide range of pharmaceuticals, metabolites and their
conjugates are excreted into the sewage system. The wastewater is treated before it
is discharged into reservoirs, river or lakes. The
n, some of the water is cleansed
again at drinking water treatment plants and piped to consumers, but most of the
treatments do not remove all drug residues. Researchers do not yet understand the
exact risks from decades of persistent exposure to random co
mbinations of low
levels of pharmaceuticals. Recent studies, which have gone virtually unnoticed by the
general public; have found alarming effects on human cells and wildlife
After application, pharmaceuticals are excreted and transported with the w
to sewage plants. Most of these substances are not biologically eliminated or
adsorbed to sewage sludge so that they reach the aquatic environment. Veterinary
drugs or pharmacological food additives are spread by dry or liquid manure to fields
11
Sources and distribution of pharmaceuticals in the environment (
[68]
People take pills. Their bodies absorb some of the medication and many even
become inactive but many others particularly those excreted renal or not absorbed
Present knowledge
indicates that as a result of wide range of pharmaceuticals, metabolites and their
conjugates are excreted into the sewage system. The wastewater is treated before it
n, some of the water is cleansed
again at drinking water treatment plants and piped to consumers, but most of the
treatments do not remove all drug residues. Researchers do not yet understand the
mbinations of low
levels of pharmaceuticals. Recent studies, which have gone virtually unnoticed by the
general public; have found alarming effects on human cells and wildlife
[70].
After application, pharmaceuticals are excreted and transported with the w
aste water
to sewage plants. Most of these substances are not biologically eliminated or
adsorbed to sewage sludge so that they reach the aquatic environment. Veterinary
drugs or pharmacological food additives are spread by dry or liquid manure to fields
12
from where they might be washed into ground, surface and tap waters [36] (see
Table 1.2, 1.3 and 1.4).
Table
1.4: Summary of concentration of target drugs in Rivers and Lakes in various
countries by µg/L
1.4 Possible effects on the environment
Antibiotic residues in the environment are suspected to induce resistance in bacterial
strains causing a serious threat for public health as more and more infections can no
longer be treated with the presently-known antidotes. Epidemic diseases in hospitals
are often caused by infections [71]. Many research groups examined the bacterial
population in STP effluents concerning elimination rate of pathogens and resistance
River, country
CBZ
DCF
SFM
IBU
TC
CTC
Reference
Blau, Germany
0.11 0.29 0.76 [65]
Elbe, Germany
0.17, 7.1 0.42 0.1 0.45 [75, 35]
Elz, Germany
0.10 [65]
Fulda, Germany
0.20 0.11 [76]
Gusen, Austria
0.13 0.16 [77]
Haringvlier, Holland
0.13 0.16 [78]
Körsch, Germany
1.2 0.22 [65]
Landgraben, Germany
0.5 [76]
Lippe, Germany
2.0 [78]
Llm, Germany
0.72 [80]
Lutter, canal
0.48 [81]
Main, German
y
0.37 [ 82]
Meuse, Holland
0.08 0.83 [78]
Neckar, Germany
0.29 0.16 [65]
Rhein, Germany
2.1 0.3 0.11 [65, 82, 83]
Ruhr, Germany
0.71 0.12 [83]
Schwarzbach,Germany
0.12 [76]
Wannsee
1.1 0.83 0.20 [81]
Pouder, USA
0.18 0.10 0.10 [84]
Pearl, China
0.15 [85]
Pader, Germany
0.01 [86]
Höje, Sweden
1.68 0.16 3.59 [87]
13
patterns [72]. Although usually more than 95% of the colonies forming strains were
eliminated during treatment, most of the remaining bacteria population showed
resistances. More than 70% of the bacteria are insensitive against at least one
antibiotic. Many show multiple resistance patterns. The most frequently observed
resistances differ from study to study. Some authors report an accumulation of
penicillin resistances, whereas others report high incidences of bacitracin,
tetracycline resistances. In many cases the genetic code for antibiotic resistance is
placed on so-called R-plasmids which can be transferred between bacteria. Some
authors examined bacteria from other compartments of the aquatic system like lake,
river and ground water [73]. Even some investigated drinking waters contained a
resistant bacterium, which was explained by an assumed fecal contamination [74].
Low concentrations of pharmaceuticals in the theory, the following negative effects
on aquatic organisms are possible:
Ecotoxicological effects
Pharmaceuticals effects
Resistance development of micro-organisms
It is clear that during the past few years a wealth of data has become available on the
levels of pharmaceuticals in the environment and their effects on the aquatic and
terrestrial organisms. There are however, still many questions that need to be
addressed before we can eventually determine whether residues in the environment
are a threat to human and environment health.
14
2 Aim of the study
The aim of this study was to characterize the extractability of human drugs and
selected metabolites from water by several types of polymer materials. For this
purpose the polymer samples were contacted with dissolved drugs and the extracted
and re-extracted amounts determined by liquid chromatography (HPLC).
Two types of polymeric membrane have been used, polyurethane foam (PUF),
commercially available and novel block copolymer membranes, synthesized in the
University of Paderborn by Dr. B. Weber (Chemistry and Technology of Coatings,
head of the group: Prof. Dr. W. Bremser).
The target drugs sulfamethoxazole (SFM), carbamazepine (CBZ), diclofenac (DCF),
ibuprofen (IBU), tetracycline (TC) and chlortetracycline (CTC) and their main
metabolites N-4-acetylsulfamethoxazole (ASFM) and isochlortetracycline (iso-CTC).
The selection of these pharmaceuticals is based on their amounts applied for medical
purposes, in as presented comprehensive reviews [10, 14, 18, 20-24, 34, 53, 57] and
their relative high concentrations found in the aquatic environment [18, 22, 20]. The
available data on the occurrence in the aqua environment [36- 39] are listed in tables
1.2 and 1.3. i.e most of the treatments do not remove all drug residues. As a result
the analytical process still can be wasted if there is an unsuitable sample preparation;
there is an urgent need to improve treatment of water and waste-water. The purpose
of this study was to enrich the sample preparation and water treatment in field of
application of analytical chemistry.
Table 2.1 and table 2.2 show the structural diversity and some chemical properties of
selected pharmaceuticals.
The metabolite ASFM is not commercially available. It was required to perform the
membrane tests and to use it as a reference substance for the calibration of the
chromatographic systems. Therefore, the metabolite had to be synthesized. As a
consequence the present study is divided into three scopes:
Synthesis of the metabolite ASFM; the iso-CTC is commercially available.
Investigation of the mass transfer of these compounds in open cell solid
membrane system; polyurethane foam (PUF) and novel synthesized
polymers (BM).
15
Investigation of the extraction properties of these materials
Investigation of the recovery (re-extraction) of drugs and some metabolites
from loaded polymers.
The main aim of the present work is to perform systematic investigation on the
removal of traces and metabolites from aqueous samples by polymer foams and
polymeric membranes. Methods were applied to quantify the analytes in water
samples by HPLC-UV technique.
Table
2.1: Structure of selected pharmaceuticals
Ibuprofen
Dicofenac
Sulfamethoxazole
N
-
4
-
Acet
ylsulfamethoxazole
Carbamazepine
Tetracycline
Iso
-
Chlortetracycline
Chlortetracycline
16
Table
2.2: Basic properties of selected pharmaceuticals (pk
a
and log P values at .
25
o
C) [88]
Name of drugs
CAS
pK
a
log P
Pharmaceutical
class
Carbamazepine (CBZ)
236.2726 13.94 2.67
Antiepileptics
Diclofenac (DCF)
318.1343 4.09 4.18±0.20
Anti-inflammation
Ibuprofen ( IBU)
206.284 4.41 3.72
N
-
4
-
Acetylsulfamethoxazole
(ASFM)
-- 5.60 1.478±0.436
Metabolites
iso- Chlortetracline (iso-
CTC)
-- 7.70 0.6±0.6
Sulfamethoxazole (SFM)
253.2752 5.81 0.887±0.419
Antibiotics
Tetracycline (TC)
a
444.4402 3.30
7.68
9.69 -0.6±0.7
Chlortetracline (CTC)
b
478.8853 3.30
7.44
9.27 0.4±0.4
pK
a
: negative logarithm of the dissociation constant, log P
: octanol-
water partition coefficient
a
Ref. [89]
b
Ref. [90]
3. Pharmaceuticals used in this study 17
3 Pharmaceuticals used in this study: basic properties
3.1 Antibiotics
An antibiotic is a drug that kills or slows the growth of bacteria. Antibiotics are a class
of antimicrobials, which includes anti-viral, anti-fungal, and anti-parasitic drugs. They
are relatively harmless to the host, and therefore can be used to treat infections. The
term, coined by Selman Waksman [91], originally described only those formulations
derived from living organisms, in contrast to chemotherapeutic agents, which are
purely synthetic. Nowadays the term ‘’antibiotic’’ is also applied to synthetic
antimicrobials, such as the sulfa drugs. Antibiotics are generally small molecules with
a molecular weight less than 2000.
Unlike previous treatments for infections, which included poisons such as strychnine
and arsenic, antibiotics were labeled ’’magic bullets’’: drugs which targeted disease
without harming the host. Conventional antibiotics are not effective in viral, fungal
and other nonbacterial infections. Individual antibiotics vary widely in their
effectiveness on various types of bacteria. Antibiotics can be categorized based on
their target specificity: ‘narrow-spectrum’ antibiotics target particular types of bacteria,
such as Gram-negative or Gram-positive bacteria, while wide-spectrum antibiotics
affect a larger range of bacteria. The effectiveness of individual antibiotics varies with
the location of the infection, the ability of the antibiotic to reach the site of infection
and the ability of the bacteria to resist or inactivate the antibiotic. Some antibiotics
actually kill the bacteria (bactericidal), whereas others merely prevent the bacteria
from multiplying (bacteriostatic) so that the host’s immune system can overcome
them [92].
3.2 Use of antibiotics
Antibiotics used to treat infections are an invaluable tool and their introduction
revolutionized the treatment of infectious disease. However, in addition to being used
to treat human disease, they have other applications. In the United States, roughly
half are used in non-human applications. Large amounts are employed in both plant
and animal farming. In animals, antibiotics are used to prevent infection as well as to
treat disease. Smaller doses are added to animal feed to promote growth. Antibiotics,
3. Pharmaceuticals used in this study 18
chiefly streptomycin and oxytetracycline, are used to control bacterial infections of
fruits and vegetables. In Germany, more than 250 t such antibiotics are used per year
[93]. Internationally, comparable data on antibiotic consumption are scarce, and
whatever information is available is heterogeneous. Usage patterns may be different
in different countries [94]. It is not surprising that antibiotics have been found in liquid
waste at animal feedlots, and have spread into many surface and ground water
supplies [95].
3.3 Antibacterial resistance in the environment
The ubiquitous presence of antibiotics has upset the delicate balance of
microorganisms in the environment. Over millions of years, bacteria have evolved a
number of strategies to coexist peacefully, including the capacity to produce
antibiotics to ward off competitors. Other organisms have an ability to destroy these
substances programmed into their genetic makeup, and having this capacity, are said
to be antibiotic resistant. Both types have always existed. However, before the wide-
spread use of antibiotics, resistant strains were a small fraction of the microorganism
ecosystem. Significant change has occurred with the large scale human use of
antibiotics because these substances kill antibiotic susceptible bacteria and thus
create favorable environments for the overgrowth of resistant strains [95].
As antibiotics become more widely used, resistant strains of both harmful and
harmless bacteria are replacing antibiotic susceptible bacteria. Furthermore, resistant
bacteria in one environment may not be confined to that specific environment, but
can be carried thousands of miles away by wind, water, animals, food, or people. And
most importantly, antibiotic resistant organisms that develop in animals, fruits, or
vegetables can be passed to humans through the food chain and environment. All of
these factors had the effect of changing the balance between antibiotic susceptible
and the antibiotic resistant bacteria in our ecosystem, locally and globally.
The widespread use of antibiotics in humans has raised several concerns related to
human and animal health. The principal area of concern has been the increasing
emergence of antibiotic resistance phenotypes in both clinically relevant strain and
normal commensal microbiota. Antibiotics are used for disease treatment,
prophylaxis and growth promotion. The concern over the use of antibiotics in
agriculture, especially for prophylactic and growth-promoting purposes, has not been
3. Pharmaceuticals used in this study 19
limited to the presumed role of antibiotics in selection of antibiotic-resistant bacteria
(pathogenic or non-pathogenic) in the animal gut. The more debatable issue arising
from chronic low-level exposure to antibiotics is whether this practice contributes
significantly to increased gene frequencies and dissemination of resistance genes
into other ecosystems. Furthermore, many antibiotics used in animal agriculture are
poorly absorbed in the animal gut. It is estimated that 25% to as much as 75% of the
antibiotics administered to feedlot animals could be excreted unaltered in feces [96,
97] and can persist in soil after land application [98, 99]. There is little information
available concerning the fate of antibiotics in the environment and their link to the
emergence of resistant genotypes found there. The annual production of livestock
and poultry waste in the United States is nearly 180 million tons (dry weight basis)
[100, 101]. And coupled with antibiotic usage, this waste is a potentially large source
of both antibiotics and antibiotic-resistant bacteria released into the environment.
Lagoons and pit systems are typically used for waste disposal in animal agriculture.
Seepage and runoff into watershed systems are of particular concern due to potential
mobilization of constituents and exposure of contaminants to humans and other
animals. Groundwater, in particular, constitutes about 40% of the water used for
public water supplies and provides drinking water for more than 97% of the rural
population in the United States [102]. Recent monitoring studies have demonstrated
the vulnerability of ground water to seepage from waste water lagoons [103]. Over a
period of several years, Krapac and coworkers found indicators such as ammonia
and feces at elevated level in ground water samples obtained up to 100 m
downstream from swine waste lagoons. This indicates that long-term impact and
environmental migration of contaminants occur [103, 104].
Molecules of tetracycline and sulfonamide antibiotics are neutral or negatively
charged when present in environmental water with a high pH, which reduces the
removal of these pharmaceuticals by conventional techniques, such as sand filtration,
sedimentation, flocculation, coagulation, chlorination and activated carbon. The
problem of water remediation in the case of tetracycline and sulfonamide antibiotics
is complicated due to the presence of Dissolved Organic Matter (DOM). Activated
carbon removes DOM poorly, since these large molecules blind the porous space of
the activated carbon and thus significantly decrease the efficiency of this sorbent
[105].
3. Pharmaceuticals used in this study 20
3.4 Tetracyclines
Tetracyclines, e.g. tetracycline (TC), chlortetracycline (CTC), dihydroxytetracycline
(DHTC), are an important group of antibiotics having a wide range of use against
human and animal pathogens [106]. They are produced by different microorganisms
including streptomyces aureofaciens [107]. They have high water solubility, whether
the pure active agent or its connection exists as a hydrochloride. So the water
solubility of tetracycline hydrochloride is 50-100 g/L [108]. In addition, tracycline
forms complexes with polyvalent cations, whereby the stability of the trivalent
aluminum and iron complexes, e.g. in liquid manure, can adsorb bivalent magnesium
and calcium complexes. However, it dissolves in organic substances [109].
Teracycylines should not be given to young children because of the negative
interaction of tetracyclines with their developing teeth. Because of their antimicrobial
activity, a negative interaction within the gut can happen within therapy. Bacteria,
fungi and microalgae are the organisms primarily affected by antibiotics, because
antibiotics are designed to affect microorganisms [110]. Table 3.1 shows the
ecotoxicological data of tetracyclines and others selected drugs.
3.4.1 Tetracycline (TC)
3.4.1.1 Characterization
Tetracycline is a bacteriostatic antibiotic which is used in human and veterinarian
medicine. Winckler and Grafe examined 6 districts in Germany. On average, 14.072
kg of this active agent with chlortetracycline was the second most frequent used
agent [111]. In its effect spectrum, tetracycline is primarily identical with
oxytetracycline and is used as a treatment of bacterial contingent diseases of the
respiratory and gastrointestinal organs of the pig [108].
Tetracycline is excreted by both the human body and other animals via urine and
feces again and to be sure up to 80-90% in humans [112, 113] and/or up to 72% in
pigs [111, 114].
Tetracycline residue was detected in both STPs (0.45 µg/L) [115, 116] and surface
waters up to 0.14 µg/L [117]. However, it has been regularly measured in
considerable concentrations of up to 66,000 µg/L in economy manure and grounds of
agricultural utility areas [118, 119], that with correspondingly economy manure (up to
199 µg/kg) in soils [120].
3. Pharmaceuticals used in this study 21
TC could also be in surface water near ground water in concentration 0.13 µg/L
[121]. Note that in drinking water samples, no TC residue was previously found.
3.4.1.2 Environmental behaviour
There is limited data detailing the behavior of tetracycline in waters just as
chlortetracycline was classified by investigations, tetracycline was also classified as
biologically not easily degradable, and the work presumes a corresponding behavior
also in surface waters.
With photochemical decomposition analysis, the results showed a half life time of 1-4
days, which was observed under semi-natural outdoors conditions in aqueous phase
[122].
TC is very stable and gives half life times in soils of < 38-63 days [119]. TC has high
K
F
and K
OC
values would appraise wisely on the strong sorption inclination at the soil
matrix [109,123]. Experiments show no considerable dismantling of these materials in
soils over a period of 5-6 months. One can find various references to its accumulation
in repeated spreading of contaminated liquid manure [120]. In areas contaminated
over a period of 3 years more than 100 µg/kg in soils tetracycline was found in the
surface and ground water in 2003/2004 in concentration of 0.13 µg/L [121].
Effects on microorganisms
Boxall, et. al. gathered a row of test results on aquatic microorganisms. The EC
50
for
Vibrio fishery is about 0.0251 mg/L [124]. Also the statements detailing the effect of
tetracycline are very different for sludge bacteria; the statements reached to 0.08 to
100 mg/L. Literature detailing the effect on soil bacteria is not limited.
Effects on algae, higher plants and lower animals
The sensitivity of algae towards antibiotics varies widely. In an algae toxicity test,
Selenastrum capricornutum was found to be two to three orders of magnitude less
sensitive to most antibiotics than microalgae Microcystis aeruginosa. The growth of
Microcystis aeruginosa was inhibited at concentrations less than 0.1 mg/L [33].
Similar observations were documented by Lützhøft et al. [125]. Blue–green algae
(cyanobacteria) seem to be sensitive to many antibiotics, for example tetracycline,
amoxicillin, benzyl penicillin, sarafloxacin, spiramycin and tiamulin [126]. L. gibba
shows first effects of TC with concentration of 194 to 230 µg/L [127].
3. Pharmaceuticals used in this study 22
Effects on invertebrates
In regards to the effects on invertebrates, there are limited data. Preliminary
indications suggest EC
50
ranging from 40.3 to 49.8 mg/L for D magna [128].
3.4.2 Chlortetracycline (CTC)
Chlortetracycline is used in the field of veterinarian medicine in the treatment of
infections of the respiratory tract, the genitourinary system, stomach and intestines.
CTC was detected in surface water up to 24,130 kg, (33% of the total in year 1997)
[129].
3.4.2.1 Environmental behaviour
S
Ø
renson et al., gave separation rates (over urine) both in cows and in pigs about
65% of the dispensed active agent quantity (related on the exit substance inc. its
metabolites) [130]. Montforts et al. gave separation rates of the unchanged exit
substance with animals about 17-75% [131].
Residues of chlortetracycline have been found in many environmental media. In
STPs, there were concentrations up to 0.28 µg/L and were detected in surface water
up to 0.16 µg/L and 0.69 µg/L [118,133]. In economy manure, CTC was proved to
have concentrations which were frequently above 1000 µg/L until max. 203.30 µg/L
[52,132]. Additionally, chlortetracycline residues in economy manure (especially pig
liquid manure) used in the agricultural field was found a maximal concentration of 810
µg/kg in soils [121, 123].
In soils, chlortetracycline is adsorbed strongly and quickly i.e more than 95% of its
adsorbents within 10 min. The sorption increases with increasing pH [133, 134].
Investigations to the biological degradation of 18 antibiotics, among other things
chlortetracyclin and tetracyclin (Closed Bottle-test after OECD 301 D; darkness, room
temperature:
20±1
o
C), showed that these must be classified as not easily
degradable. The half life value times of chlortetracyclin and that of its metabolites are
shorter in light [135, 136].
Effect on microorganisms
There are two investigations on the effect of chlortetracyclin on sludge bacteria, the
EC
50
value is about 30 µg/L and 400 µg/L [137, 138]. An aeruginosa reacts in 50 µg/L
[137]. To ground bacteria, there is no effect concentration. Boxall et al. observed that
values of more than 0.6 mg/kg is no impairments to ground respiration [124]. Winkler
3. Pharmaceuticals used in this study 23
and Grafe report of tetracycline resistent clostridien in the ground water under
fertilized soils [129].
Effects on algae and higher plants
L. Gibba shows first impairment at concentrations of 36 to 59 µg/L [126]. Similar to
oxytetracycline, chlortetracycline influences in concentrations over 160 mg/kg, which
is toxic to some grain plants and fodder plants [28, 139].
3.5 Sulfonamides
The sulfonamides are synthetic bacteriostatic antimicrobials that competitively inhibit
conversion of p-aminobenzoic acid to dihydropteroate, which bacteria need for folic
acid synthesis and ultimately purine and DNA synthesis. Humans do not synthesize
folic acid but acquire it in their diet, so their DNA synthesis is less affected. Two
sulfonamides, sulfisoxazole and sulfamethizole are available as single agents for oral
administration. Sulfamethoxazole in combination with trimethoprim discussed below
[140].
The sulfonamides are readily absorbed orally and after topical application to burns,
sulfonamides are distributed throughout the body. They are metabolized mainly by
the liver and excreted by kidneys. Use in pregnancy results in high levels [141]. They
have a wide spectrum against Gram-positive and many Gram-negative bacteria,
plasmodium and toxoplasma. However, resistance is widespread, and resistance to
one sulfonamide indicates resistance to all.
3.5.1 Sulfamethoxazole (SFM)
Sulfamethoxazole (SFM) is bacteriostatic antibiotic. It is most often used as part of a
synergistic combination with trimethoprim in a 5:1 ratio in co-trimoxazole, which is
also known as Bactrim, Septrin, or Septra. Its primary activity against susceptible
forms of streptococcus, staphylococcus aureus, Escherichia coli, Haemophilus
influenzae, and oral anaerobes. It is commonly used to treat urinary tract infections.
In addition it can be used as an alternative to amoxicillin-based antibiotics to treat
sinusitis. It can also be used to treat toxoplasmosis. In Germany, 53,600 kg of the
active agent sulfamethoxazole was sold in 2001.
3. Pharmaceuticals used in this study 24
It is one of the top-selling antibiotics in the human medicine next to amoxicillin [142].
For ecotoxicological data of sulfamethoxazole see table 3.1.
3.5.1.1 Metabolism
SFM after oral application is quickly and completely desorbed in the upper stomach-
intestine-section. The predominantly renal rate of elimination takes place to 61% of
doses as the antibacterial not active N4-acetyl-sulfamethoxazol, to 15% as N1-
Glucuronide and to a further part as a conjugate by active sulphuric acid.
The known metabolism of SFM involves acetylation and oxidation leading to N4-
acetylsulfamethoxazol (ASFM) and N-hydroxysulfamethoxazole (SFM-NOH).
Hydroxylation also takes place to SFM metabolism leading to 5-methylhydroxy-
sulfamethoxazole (SFM-Me), and N4-acetyl-5-methylhydroxylsulfamethoxazole
(SFMMOH), as shown in figure 3.1.
Moreover SFM is glucuronidated leading to sulfamethoxazole-N1-glucuronide (Glucu-
SFM) [113, 143-148]. About 50-60 % of applied dose in human body was excreted as
the inactive metabolite (ASFM), 15 % as the conjugate metabolite (SFM-Glu), and
only 15-20 % as the active compound [149].
Figure 3.1: Major pathways of the oxidative metabolism of SFM in human [150]
H
2
N S
O
NO
CH
3
O
N
O
OH
COOH
OH
OH
ASFM SFM-Glu
SFM
3. Pharmaceuticals used in this study 25
The SFM was not cytotoxic enough to determine EC
50
values, it inhibited EROD
activity.
The occurrence of sulfamethoxazol is to be regarded as a ubiquitous. It regularly
reaches to a concentration of more than 1 µg/L in sewages. However, the
concentrations lie as a rule around one or two orders of magnitude lower than in
sewages. In the river Rhine, concentrations of 0.023 to 0.106 µg/L were determined
[150, 151]. In the Wupper, SFM was found in a concentration of 0.051 to 0.071 µg/L
[140], and high concentrations in surface waters about 1 µg/L, while in ground water
in the area of sewage, water was about 1.6 µg/L in Finland 2007 [18].
Sulfamethoxazole is classified by several authors as biological, not degradable and
persistent in the environment [140,152]. SFM is hardly removed by photo-
degradation. With a low log K
ow
of 0.89, it is well water-soluble with slight sorption
ability at the sediment. Sulfamethoxazol show a high mobility in ground water and
there with one possible entry into the ground water as well as an extraordinary
persistent similar in sludge [153].
3.5.1.2 Environmental effects
Effects on microorganisms
The toxic effect of Sulfamethoxazol on many microorganisms was suppred. EC
50
>
100 µg/L was determined for sludge bacteria [135]. It is clear that the concentrations
previously measured in waters hardly lead to a persistent interference of the bacterial
communities. More frequently it observed that germs, that are stopped durably a low
concentration of sulfamethoxazol in sewage treatment plants, are resistant to this
antibiotic, for example E. coli out of sewage treatment plants and isolated resistance
plasmid out of sludge bacteria [154].
3. Pharmaceuticals used in this study 26
Table 3.1: Active drugs under study: basic properties and ecotoxicological data
Parameter
CBZ
DCF
IBU
SFM
TC
CTC
CAS [14]
298-46-4 15307-86-5 15687-27-1 723-46-6 60-54-8 57-62-5
Molecule
formula
[155]
C
15
H
12
N
2
O C
14
H
11
C
l2
NO
2
C
13
H
18
O
2
C
10
H
11
N
3
O
3
S
C
22
H
24
N
2
O
8
C
22
H
23
ClN
2
O
8
MW (g/mol)
[155]
236.27 296.15 206.28 253.28 444.44 478.89
Trade name
[28]
Tegratal
Biston
Calepsin Voltaren Advil Gantanol Sumycin
Panmycin Aureomycin
Use/origin
Analgesic,
antiepileptic
Analgesic,
anti-
inflammatory
Analgesic,
anti-
inflammatory
Antibiotics Antibiotics Antibiotics
Solubility in
water (mg/L)
25
o
C [155]
112 242 291 610 232 230
M.p [155]
190-192
o
C 156-158
o
C 78.87
o
C 167-169
o
C 172
o
C 185
o
C
pKa [155]
13.94±0.2 4.18±0.2 4.41±0.2 5.81±0.5
1.39±0.1
3.30
7.68
9.69
3.30
7.44
9.27
Log P [155]
2.67±0.38 3.28±0.36 3.72±0.23 0.89±0.42 -0.6±0.7 0.4±0.4
Excretion
Urine Biliary, only
1% in urine - Renal Fecal,
Renal Renal, Biliary
Half life (hour)
25-65 1.2-2 - 10 6-11 5.6-9
Consumption
(tons/year) [14]
88
a
, 40
b
,
38
d
86
a
, 26
b
344
a
, 162
b
,
14
c
58
a
- 140
a
Tot
al removal
via wastewater
treatment [156]
7-10% 69-75% 90-99% 67% - -
(PEC
sw
, ng/L)
[155]
1460
a
- - 895
a
- -
(DDD, g/d)
[19]
1 0.1 1.2 2 0.03-0.2 0.03-0.2
Environmental
risk indicators
[156]
High
volumes;
long-term
prescription;
persistent
Very high
prescription
and over-the-
counter;
detected in
the
environment
Very high
prescription
and over-
the-counter;
detected in
the
environment
High volume
detected in
the
environment;
concerns
over toxicity
and
antibacterial
resistance
High
volumes;
long-term
prescription;
persistent
antibacterial
resistance
and
prescription;
persistent
a
Germany in 2001,
b
UK in2000,
c
Australia,
d
France in 1998
4. Analytical extraction techniques 27
Effects on algae, higher plants and lower animals
The effect of sulfamethoxazol on algae was examined and found in the chronic green
alga test with P. subcapitat (72 h) EC
50
is 520 µg/L [157]. Lemna gibbons on the
other hand, were clearly more sensitive to the substance. The EC
50
in 81-249 µg/L,
the EC
10
is quite about 11-17 µg/L [127]. Liebig in 2005 determined NOEC-values for
S. suspicious of 2.5mg/l (growth test) and for Lemna gibbons is about 10 µg/L (7d
photo toxicities) [158].
Isidori et al. determined the comparative sensitivity and the growth test with C. dubia
(7 d) an EC
50
of 210 µg/L [157]. In acute test systems on the other hand, the effect of
concentration was determined over two orders of magnitude about that in the mobility
test with D. magna (EC
50
of 25.2 mg/L, with C. dubia of 15.5 mg/L).
Tests with vertebrate did not refer to a mutagenic effect of SFM [158].
3.6 Neuroactive compounds (antiepileptics, antidepressants) - Carbamazepine
In 1968, carbamazepine (CBZ) was approved, initially for the treatment of trigeminal
neuralgia. Later in 1974, it was approved for partial seizures. Ethosuximide has been
used since 1958 as a first-choice drug for the treatment of absence seizures without
generalized tonic-clonic seizures. Valproate was licensed in Europe in 1960 and in
the United States in 1978, and now is widely available throughout the world. It
became the drug of choice in primary generalized epilepsies and in the mid 1990s
was approved for treatment of partial seizures. These anticonvulsants were the
mainstays of seizure treatment [159].
Understanding the mechanism of action and pharmacokinetics antiepileptic
antidepressants (AEDs) is important in clinical practice so that they can be used
effectively, especially in multidrug regimens. Many structures and processes are
involved in the development of a seizure, including neurons, ion channels, receptors,
glia, and inhibitory and excitatory synapses. The AEDs are designed to modify these
processes to favour inhibition over excitation in order to stop or prevent seizure
activity [159].
Today carbamazepine (CBZ) is the most commonly used antiepileptic agent. It is
used therefore not only to the mood brightening, but also applied as specific
analgesic for trigeminal neuralgia [160]. In 1998, half of the doses of antiepileptic
drugs prescribed in Germany were CBZ, amounting to 74 million DDDs [161], hence
4. Analytical extraction techniques 28
the total prescribed amount in 1998 was 74 t. In 2001, the use of CBZ increased to
87.6 t/year. A part of 12% was applied in hospitals [162]. It was detected most
frequently and in highest concentration in wastewater and in soils under irrigation
with wastewater for approximately 90 years up to 6.3 and 6.5 µg/L respectively
[23, 163].
3.6.1 Metabolism
Thirty three metabolites of CBZ have been identified from human and rat urine [164].
After oral administration, 1-3% of CBZ is excreted as the parent compound [165]. In
humans, the physiologically still active main metabolite is EP-CBZ, which is further
metabolised to inactive compounds and then excreted as glucuronides (see Fig. 3.2).
N
NH
2
O
N
NH
2
O
OH
N
NH
2
OOH
N
NH
2
O
O
N
NH
2
O
HO OH
N
O NH
2
CH
2
OH
H
Figure 3.2: Major pathways of the oxidative metabolism of CBZ in human [166]
3.6.2 Environmental behaviour
Carbamazepin is described by several authors as extraordinarily persistent. It is
hardly degraded biologically in the surface and ground water [113, 167, and 168].
CBZ is degraded comparatively well photochemically. Some authors found acertain
sorption ability due to K
ow
2.25; slight elimination of the material during the bank
filtration or the sewage cleaning on a good mobility [169, 170]. Loeffler et al. indicate
that the main metabolite10, 11-dihydroxy-carbamazepin, based on its clearly
CBZ
25%
40%
Diol-CBZ
(80% of EP
-
CBZ)
CBZ-3OH
CBZ
-
2OH
EP
-
CBZ
9-AC
(minor)
(major)
4. Analytical extraction techniques 29
increased polarity at the sediment sorbent [171]. Table 1.3 shows ecotoxicological
data of CBZ.
Environmental field studies have shown that CBZ are one of the most frequently
detected pharmaceuticals in sewage treatment plant (STP) effluent (see table 4.1) It
is proved in Germany with over 1 µg/L in sewages [20, 23]. Also in river water, CBZ
could be proved in the Rhine in a concentration of 0.1 until 2.1 µg/L [172]. A
concentration of up to 2 µg/L was found in the River Lippe [173]. The medicine
material was proved by several authors in the ground water with values up to 0.9
µg/L [174]. Even in the drinking water 0.03 µg/L were found [175]. As one of few
materials, CBZ was found moreover in the drainage water of a dump; concentrations
determined there were between 0.4 and 3.0 µg/L [148].
3.6.3 Environmental effects
Effects on micro organisms
Ferrari et. al. investigated the effect of carbamazepin on microorganisms. An EC
50
of
more than 81 mg/L (30 min) was found for Vibrio fishery in the bacterium test [176].
Effects on algae higher plants and lower animals
The active agent was tested in several studies with the chronic green alga test for its
ecotoxicology effectiveness. Applying test duration of 96 h, a NOEC of more than
100 mg/L for Pseudokirchneriella subcapitata was proved [176]. Cleuvers received
an EC
50
of the value same order of magnitude [177]. Desmodesmus subspicatus
reaction reached in 85.0 mg/L an EC
10
of 27.0 mg/L. An investigation of toxic effects
of carbamazepine in higher aquatic plants result, an EC
50
25.5 mg/L as indicated for
the growth test with the water lines Lemna gibbons [178].
The invertebrate showed the highest sensitivity in ecotoxicology tests towards
carbamazepine. For chronic Daphnis test with 7d duration, Ferrari et al. gives a
LOEC of 100 µg/L as well as a NOEC of 25 µg/L. The results of the acute test lie in
the level of mg/L [176]. Cleuvers indicates an EC
50
of 157mg/l and/or an EC
10
of 12
mg/L for the acute toxicity test with Daphnia magna [177].
The toxicity of carbamazepine for vertebrates was tested by Hanisch et al. A LC
50
of
251.9 mg/L is quoted for the acute fish toxicity test [179]. Ferrari et al. determined
with the test organism Danio rerio a LOEC of 50 mg/L and a NOEC of 25 mg/L [180,
181].
4. Analytical extraction techniques 30
3.7 Analgesics and anti-inflammatory drugs
Analgesics are the drugs that relieve pain, anti-inflammatories are drugs used to
reduce inflammation: the redness, heat, swelling and increased blood flow found in
infections and in many chronic non-infective diseases such as rheumatoid arthritis
and gout. The widely used non-steroidal anti-inflammatory drugs (NSAID) are
ibuprofen, naproxen, diclofenac. For ecotoxicological data of diclofenac and
ibuprofen see Table 3.1.
3.7.1 Diclofenac (DCF)
Diclofenac is used as an analgesic, but also in the therapy of rheumatic diseases. It
is therefore both to incorporate into the active agent group of the analgesics and the
antirheumatoids and anti holistics. The wide use paket made the material with 85,800
kg sale quantities in 2001 to one of the usually sell active agents in Germany [142].
3.7.1.1 Metabolism
Diclofenac, is a phenylic acid derivative, oxidized in the liver relatively quickly and
appears in urine hydroxyl derivative (see figure 3.2). Only 1% of the dispensed dose
remains unchanged [182].The excretion of the metabolite is about 70% renal and to
30% by means of the faces [183]. Main metabolites are 4′- hydroxydiclofenac (40%),
5-hydroxydiclofenac, 3′-hydroxydiclofenac and 4′,5- Dihydroxydiclofenac (respectively
5-10%). About 15% of the dose is eliminated as a conjugate [184].
Lilienblum et al. found a concentration of to 3.4 µg/L of DCF in the ground water
[185], in the area of the wastewater irrigation of Braunschweig (Germany).
Stump et al. detected DCF in the range from 0.001 - 0,006 µg/L in the drinking water.
In sewage sludge 5 µg/kg TS of DCF were found at most 212 µg/kg TS [186].
4. Analytical extraction techniques 31
Figure 3.3: Major oxidative metabolism products of DCF in urine [183]
3.7.1.2 Environmental behaviour
Diclofenac is hardly decomposed in water [167]. On the other hand, the photo
degradation seems to play an important role. DCF is to be regarded as a lipophilic
substance K
ow
is 4.02-4.51 [187]. It is comparatively easily adsorbed by sediment.
The behavior of diclofenac in the ground is strongly pH-dependent [188-190]. The
compound is very mobile in neutral and basic soil and therefore available for easier
degradation and transportation under certain circumstances into the ground water.
Diclofenac is usually present in concentrations of more than 3 µg/L in sewages water
and sewage treatmen [21]. In surface waters the maximum value is up to 2 µg/L
[191]. In the Rhine, concentrations were determined in the range of 0.05-0.30 µg/L
[192–194]. Whereas in the Elbe 0.4 µg/L of DCF were found and in the Ruhr more
than 0.71 µg/L as shown in table 1.4. Similar concentrations of diclofance were found
repeatedly in the ground water. Lilienblum et al. report findings the ground water of
irrigation area of Braunschweig, Germany found 3.4 µg/L of DCF [191]. In drinking
water, Stump et al. found 0.001-0.006 µg/L of DCF [76]. DCF concentrations
4. Analytical extraction techniques 32
between 5 µg/kg and maximally 212 µg/kg TS were determined in sewage sludge
[189].
3.7.1.3 Environmental effects
In the lamp bacterium test, Ferrari et al. showed the EC
50
of DCF 11.5 mg/L [176].
Effect on algae, higher plants and low animals
The active agent was tested in several studies with the chronic green alga test.
Ferrari et al. determined a LOEC of 20 mg/L and a NOEC of 10 mg/L, in a test
lasting for 96 h, [176]. Cleuvers indicates an EC50 of 72 mg/L for D. subspicatus.
Diclofenac in higher aquatic plants showed an EC
50
values
in the growth test with
L. gibbons when duration is reached, a LOEC of 2 mg/L as well as a NOEC of 1mg/L
[195].
Effects on vertebrates
In the acute fish toxicity test, a LC
100
was assessed of 320 mg/L [177]. Ferrari et al.
shows with the test organism Danio rerio (Zebra fish) a LOEC of 8 mg/L and a NOEC
of 4 mg/L [176]. A 28-day exposure of rainbow trout in 5 µg/L of DCF led to serious
pathological variations in kidney and gill [196]. Moreover that the toxic effect of
diclofenac was increased when it was used as a veterinary drug. In India and
Pakistan, over cadaver of the farm animal (cows) treated with this active agent
arrived the material in handle bird populations. It was reported that one abundant
vulture died of kidney failure [198].
3.7.2 Ibuprofen (IBU)
Ibuprofen is used based on its painkiller and anti- inflammatory effect as well as
analgesic and a treatment for rheumatism with about 345.000 kg/a. It is the most
frequently sold analgesic in Germany after Acetylsalicylic acid and Paracetamol
[142,192].
3.7.2.1 Metabolism
The separation of Ibuprofen reaches from 60 to 90% as metabolites, e.g. as a
conjugate [197]. About 1% of the active compound unchanged is eliminated with the
urine [198].The main inactive pharmacologic metabolisms are [2, 4′- (2--
Carboxypropyl)-phenylpropionic cid (CA-IBU) as shows in figure 3.4.
4. Analytical extraction techniques 33
Fig. 3.4: Major pathways of the oxidative metabolism of IBU in human [199]
3.7.2.2 Environmental behaviour
Ibuprofen is easily biodegraded as described [28,200]. Ibuprofen is also classified as
little persistent in ground water. It s concentration is reduced under aerobic conditions
to the half [171]. K
ow
- values in the range of 3.5 - 4.5 [179,200,201] Ibuprofen expels
as lipophil moderate, with a breakthrough into the ground water is not at low pH-
values and high concentrations of organic substance to rake. But also at basic pH,
the active substance in grounds is comparatively well retained [192].
Ibuprofen is regularly found in sewages and sewage treatment plant expiration in
concentrations between 0.1 and 1µg/L. In surface waters, IBU was also frequently
found, for example In the Rhine, in concentrations from 0.006 to 0.072 µg/L [186, 28,
188] and in the Ruhr (Germany) with a value of 0.14 µg/L [163]. Ivashechkin
indicates IBU as a maximum in surface waters 1.5 µg/L [202]. In ground water IBU
was found in a maximum concentration of 0.51 µg/L [189, 204]. Also in drinking water
the highest concentration found was 0.003 µg/L [175, 187]. In sewage sludge,
Ibuprofen was assessed between 0.5 µg/kg and 29 µg/kg DS [202].
3.7.2.3 Environmental effects
Effects on algae and higher plants and low animals
The ecotoxicologic effect valued for bacteria is 12.3 mg/L [179]. In the green alga test
with D. subspicatus, Cleuvers indicates an EC
50
of Ibuprofen of 315 mg/L [178].
Skeletonema costatum and Lemna gibbons react clearly more sensitive to the
substance.
4. Analytical extraction techniques 34
It has sensitivity effects on invertebrate, e.g. D. magna EC
50
- value around 10 mg/L
[28, 201]. Cleuvers is referred to investigate the same organism with the result of an
EC
50
of 108 mg/L [180]. For Daphnia magna and Mysidopsis bahia, NOEC-values of
3 and 30 mg/L are quoted [179].
Statements to the ecotoxicological effect of Ibuprofen on vertebrates are quoted, the
NOEC for Lepomis machrochirus (rainbow trout) amounts to 10 mg/L [179].
4 Analytical extraction techniques
In recent years, several pretreatment techniques and methods have been developed
for the analysis of various contaminants or residues of pharmaceuticals and
corresponding metabolites in environmental and biological samples. Despite the
achievements in analytical science, there are still challenges. One challengen lies in
determining pharmaceuticals in various complex matrices such as wastewaters,
surface waters, sediments and biological fluids. Most developed analytical methods
require several steps consuming time and solvents. In ecological risk assessment for
chemical pollutants, it is important to quantify the concentrations of in aqueous
samples for approximate characterization of the bioavailability fraction. Sample
preparation becomes a key step in modern chemical analysis. It is an essential part
of any analytical procedure for sample pre-concentration or enrichment and removal
of contaminants [204]. The most widely-used sample preparation techniques are
Liquid-Liquid extraction (LLE) [205] and solid–phase extraction (SPE) [206]. LLE is
the traditional technique for the extraction of organic analytes from aqueous
solutions. The basis is the partition of the dissolved analytes between the organic
phase and the aqueous solution according to their partition coefficients.
SPE techniques are perhaps the most popular in sample preparation especially for
organic analysis. The principle of SPE is based on sorption of analytes on a sorbent.
The LLE technique is well-known and still widely used, although now it’s less
attractive and is partly being replaced by other techniques. This is because of the
following disadvantages of this technique:
They are tedious and time-consuming, especially when extracting aqueous
complex samples, which demands many steps before a clean extraction can
be obtained.
4. Analytical extraction techniques 35
They are not easy to automate.
They form emulsion which makes it difficult to separate.
They are not environmentally friendly, due to large volumes of solvents used.
However, with LLE, large enrichment factors can be obtained despite the cited
drawbacks.
Inspite of its simplicity, it lacks selectivity during extraction analysis in complex
matrices such as plant extracts, foodstuffs, and wastewater [207].
There are a number of different membrane techniques which have been suggested
as alternative to the SPE and LLE techniques (see table 4.1).
Table 4.1: Different major membrane techniques used in analytical application [208]
Technique
Abbreviation
Membrane
type
Principle
Driving
force
Phase
combinations
used
Mainly
Combined
with
Dialysis
Porous Size-
exclusion Concentration
difference Aq/M/aq LC
Electrodialysis
ED Porous
Size-
exclusion
and
Selective
ion
transport
Potential
difference Aqueous LC
Filtration
Porous Size-
exclusion Presure
difference Aqueous LC
Supported-
Liquid-
membrane
SLM Non-porous
Difference
in
Partition
coefficient
Concentration
difference Aq/org/aq LC,GC,CE
M
icroporos
membrane
Liquid-Liquid
extraction
MMLLE Non-porous
Difference
in
Partition
coefficient
Concentration
difference Aq/org/org LC,GC
Semipermeable
membrane
device
SPMD Non-porous
Difference
in
Partition
coefficient
Concentration
difference Aq/polymer/org LC,GC
Polymeric
membrane
extraction
PME Porous
Non-porous
Difference
in
Partition
coefficient
Concentration
difference
Aq/polymer/org
Org/polymer/aq
Aq/polymer/aq LC,GC
Membrane
extraction
with sorbent
interface
MESI Non-porous
Difference
in
Partition
coefficient
Concentration
difference Liq/polymer/gas
Gas/polymer/gas
GC
Aq: Aqueous, M: membrane, org: organic, Liq: Liquid
4. Analytical extraction techniques 36
An area enjoying much attention by various research groups is developing polymeric
membrane-based extraction techniques (PME). They can be simple, cheap, highly
selectivity, easy to automate, high enrichment and can be miniaturized [83, 209-215].
4.1 Principle of polymeric membrane extraction
By exchanging the supported liquid membrane (SLM) with a polymeric membrane,
such as a silicone rubber, polyurethane foam, and diphenylethylene polymeric
membrane, the membrane life time can be considerably increased. This removes one
of the possible drawbacks of SLM extraction, namely the relative instability of the
liquid membrane reduces the scope for chemical tuning (e.g. the application of
carriers) of the extraction process. This especially limits the possibilities of extraction
of relatively polar analytes, where the hydrophobicity of the membrane has to be
reduced. Additionally, polymeric membranes lead to slower extractions, because of
larger diffusion coefficients in polymers than in liquids. The latter version is
sometimes termed membrane-assisted LLE [83]. A variation that does not seem to
have been further used is the “reversed permeation membrane” which is a one-sided
membrane. First the sample is brought into contact with the membrane, which
absorbs the analytes of interest, and later the acceptor contacts the same side of the
membrane desorbing the analytes. In fact, this is not a real membrane operation,
rather some kind of solid-phase extraction [216].
4.1.1 Polymeric membrane extraction (PME)
Using a porous or a non-porous membrane, solid polymeric membrane such as a
plasticized, silicone rubber, cellulose, polyether, polystyrene and polyester
(polyurethane) membrane instead of a supported liquid, the life of the membrane can
be considerably increased. One of the potential drawbacks of supported liquid
membrane extraction (SLM), is the relative instability of the liquid membrane, is
thereby by passed. However, this involves a fixed composition of the membrane, so
the possibilities for chemical tuning (e.g. the application of carriers) the extraction
process are reduced [83, 217]. This especially limits the possibilities of extraction of
relatively polar analytes, where the addition of various ion-pair or complex formers to
the membrane is imperative. Also, polymeric membranes lead to slower extraction as
diffusion coefficients are larger in polymers than in liquids. On the other hand, the
4. Analytical extraction techniques 37
membrane is virtually insoluble in most common solvents, so any combination of
aqueous and organic liquid can be used as the donor and acceptor phases.
Application of polymeric membranes has been described both with an aqueous,
trapping acceptor and with an organic solvent in the acceptor channel. On the other
hand, the membrane is virtually insoluble in most common solvents, so any
combination of aqueous and organic liquid can be used as the donor and acceptor
phases. Application of polymeric membranes has been described both with an
aqueous trapping acceptor and with an organic solvent in the acceptor channel [83,
217, 218]. The latter version is sometimes termed membrane-assisted LLE [218], and
is somewhat similar to micro-porous membrane liquid-liquid extraction (MMLLE), with
the additional feature that the dissolution of the analytes into the membrane polymer
will influence the mass transfer, leading to slower extraction but a more stable
system.
The polymer membranes have been used in analytical chemistry, instead of
precursors methods, to protect the ecosystem such as soil, surface and waste water
from environment pollution, e.g., i) removal of herbicides and other organic trace
compounds from water and soil samples [207, 219] ii) carriers in aqueous membrane
solution to remove inorganic and organic pollutant [220-224].
4.1.2 Diffusion in polymers
The concept that the local environment around the permeating molecule determines
the diffusion coefficient of permeate is key to understand diffusion in polymer
membranes. Polymers can be divided into two broad categories-rubbery and glassy.
In a rubbery polymer, segments of the polymer backbone can rotate freely around
their axis; this makes the polymer soft and elastic. Thermal motion of these segments
also leads to high permeant diffusion coefficients. In a glassy polymer, steric
hindrance along the polymer backbone prohibits rotation of polymer segments; the
result is a rigid, tough polymer. Thermal motion in this type of material is limited, so
permeant diffusion coefficients are low. If the temperature of a glassy polymer is
raised, a point is reached at which the increase in thermal energy is sufficient to
overcome the steric hindrance restricting rotation of polymer backbone segments
[225].
5. Polyurethane foam as a sorbent in analytical chemistry 38
5 Polyurethane foam as a sorbent in analytical chemistry
5.1 Polyurethane foam: The sorbent material
Polyurethane foam (PUF) presents significant interest in analytical chemistry due to
its special characteristics as a sorbent material: high efficiency, versatility, chemical
and mechanical stability, resistance to organic solvents, relatively low cost and wide
availability. The unique sorption property of this polymer is a combination of various
hydrophilic and hydrophobic centers and the reactive terminal groups [226].
Flexible and rigid polyurethane foam (PUF) of open-cell and closed-cell structures
with a wide range of properties have been manufactured. Rigid polyurethane foam is
one of the most effective practical thermal insulation materials, used in applications
ranging from modest domestic refrigerators, mattresses, cars and domestic settings.
From the analytical point of view, polyurethane foams can be used as effective
sorbents for the separation and preconcentration of organic and inorganic
substances from various media [208, 227].
In 1970, Bowen
initiated the use of
polyurethane foam for the sorption and recovery of some inorganic and organic
components from aqueous solution [228]. A year later, Gesser et al. suggested the
application of untreated polyurethane foams for the sorption of trace organic
contaminants from water using a batch squeezing technique [229]. In 1972, Braun
and Farag initiated the application of polyurethane foams for separation purposes,
but in a completely different way [230]. By taking advantage of the spherical
membrane-shaped geometry of the polyurethane foams, they were able to use foam
column operations as a substitute for the traditional granular supports in an extraction
chromatographic system. These pioneering studies in several unloaded and loaded
foamed polyurethanes demonstrate versatile applications in separation chemistry.
The most distinctive feature of polyurethane foams as solid sorbents is their
membrane structure. It is this which differentiates them from all other types and/or
sorts of solid sorbents used in separation chemistry which all are compact (granular)
or porous bulky solids. In the majority of chemical separations using membranes, the
separation of ions and/or molecules is accomplished through the membrane, i.e. the
solid membrane is not a separation in between two similar or different phases. On the
contrary, with polyurethane foams, the foam membranes act as true sorbents, i.e the
ions and/or molecules to be separated or preconcentrated are retained, i.e. absorbed
5. Polyurethane foam as a sorbent in analytical chemistry 39
onto or into the membranes [231].
The other unique advantage of using solid foam
membranes over bulky (porous) solids is the well-known fact that the diffusion rates
of chemical species in membranes offer a wider range of possibilities for chemical
modification than normally found with bulky (granular) solids [226].
5.2 Fundamental chemistry of polyurethane foam
Polyurethane foam can be defined as plastic materials in which a proportion of solid
phase is replaced by gas in the form of numerous small cells. The gas may be in
continuous phase to give an open cell material or it may be discontinuous, i.e. in the
form of discrete, non –communicating cells. From the geometrical point of view, if the
gas bubbles occupy a volume smaller than 76%, they may be spherical in shape, but
if they occupy a larger volume, the shape will likely be distorted and have the
geometric shape of either a polyhedron, a dodecahedral on average [226]. Figure 5.1
shows typical polyurethane foam in which the bubbles (cells) occupy 97% of the
volume.
The polymer is distributed between the walls of the bubbles and the lines, (called
strands), where bubbles intersect, and the walls of the cell are the factual
membranes. In open cell flexible polyurethane foam, at least two windows in each
cell must be ruptured for fluids to pass freely through the foam.
Fig. 5.1: Scanning electron micrograph of typical polyurethane foam structure [232]
5. Polyurethane foam as a sorbent in analytical chemistry 40
5.3 Polyurethane foam preparation
The pioneering work on PU foam was conducted by Otto Bayer and his coworkers in
recognized that using the polyaddition principle to produce polyurethanes from liquid
diisocyanates and liquid polyether or polyester diols was potentially a very promising
strategy, especially when compared to already existing plastics that were made by
polycondensation or polymerizing of olefins.
When PUF was applied on a limited scale as an aircraft coating, it was not until 1952
that polyisocyanates became commercially available. Commercial production of
flexible PUF began in 1954, based on toluene diisocyanate (TDI) and polyester
polyols [233].
The two important reactions in the preparation of urethane foams are those between
isocyanate and hydroxyl compounds polyether polyols and those between isocyanate
and water. The former reaction for the formation of a urethane group can be
considered as a chain-propagation reaction [234].
C ONR +OH
R´ RNCOR´
urethane
H
O
In the second reaction, water-isocyanate is responsible for the foam formation by the
liberation of carbon dioxide as in situ blowing agent. The first step of this reaction is
the formation of unstable carbamic acid, which decomposes to form carbon dioxide
and amine.
The latter may react with an additional isocyanate to produce substituted urea.
Alternatively, carbamic acid may react with another isocyante molecule to produce
carbamic acid anhydride, which decomposes to substituted urea and carbon dioxide.
(eq. 1)
(eq. 2)
5. Polyurethane foam as a sorbent in analytical chemistry 41
RNCO+R NH C
O
OH
H
2
ORNCOR NH C
O
O
carbamic acid
+ CO
2
C
O
NHR
anhydride
R NH C
O
NHR
The main reactions, which lead to branching and cross- linking, are the isocyanate
reaction producing allophanate linkages (eq. 4) and the isocyanate-urea reaction,
which produces biuret (see eq. 5).
Polyols represent the largest single component in foam preparation. In general,
polyols in the molecular weight range of 400 to 6000 are employed. The most
common isocyanate used in flexible foam production is a distilled toluene
diisocyanate usually referred to as TDI. It is a blend of the 2, 4- and 2, 6- isomer in
the ratio of 80:20 by weight. Another blend of 65% of 2, 4- isomer and 35% of 2, 6-
isomer is sometimes used for the production of high load-bearing flexible foams
[226].
5.3.1
Physical and chemical properties of polyurethane foam
Generally, the physical properties of polyurethane foams depend on the method by
which they are prepared. For example, to ensure that the windows are not ruptured in
the final stage of expansion is dependent on the relative rate of molecular growth
(gelation) and gas reaction. The appropriate tuning of these factors give rise to
flexible (open cell) or rigid (closed cell) foams. In polyurethane foam preparation, the
variety in choice of simple molecules is great and consequently, the properties of the
product are wide. Choice of the polyol has a major effect on the mechanical
properties of the foam, such as rigidity and flexibility [235]. The cross-link density of
the urethane polymer determines whether the foam will be flexible (low cross-link
density) or rigid (high cross-link density). Flexible foams are prepared from polyols of
(eq. 4)
(eq. 5)
(eq. 3)
5. Polyurethane foam as a sorbent in analytical chemistry 42
moderately high molecular weight and low degree of branching, while rigid foams are
prepared from highly-branched resins of low molecular weight.
The chemical properties of polyurethane foams are also a function of the preparation
process. For example, solvent resistance of polyurethane structure increases at
higher cross- link densities. The solvent resistance appears to be invariant to the type
of aromatic diisocyanate, although it is reduced with the use of a large excess of
isocyanate. It was reported [236] that aliphatic and cycloaliphatic isocyanates can
produce a polymer with an outstanding resistance to sunlight. This is because
aliphatics are normally less photosensitive than their aromatic counterparts. The
mechanical properties of polyurethane foams are highly dependent on the proportion
of the allophanate linkage which increases with reaction time and temperature for
toluene diisocyanate-based urethanes [236].
Several investigations have been carried out to determine the relative proportion of
allophanate, urea, urethane, and biuret linkages and also the amount of the
unreacted (free) NCO group using infrared spectroscopy and magnetic reasonance
imaging methods (MRI) [113,115,116]. Foams prepared from the reaction of toluene
diisocyanate with polyol are generally found to have lower free NCO groups than
those prepared from diphenylmethane diisocyanate. Bowen [228] examined the
chemical resistance of some batches of commercial polyurethane foams having
different densities and claimed that they are rather stable and inert. The foam
batches tested degraded when heated between 180 and 220
o
C, and slowly turned
brown in ultraviolet light. They were dissolved by concentrated sulphuric acid,
destroyed by concentrated nitric acid, and reduced alkaline potassium
permanganate. They were mostly unaltered, apart from reversible swelling, by:
water
hydrochloric acid up to 6 mol/L
sulphuric acid up to 2 mol/L
glacial acetic acid
2 mol/L ammonia
2 mol/L sodium hydroxide solution
This also includes solvents such as light petroleum, benzene, carbon tetrachloride,
chloroform, diethyl ether, diisopropyl ether, isobutyl methyl ketone, ethyl acetate,
isopentyl acetate and alcohols. It was also noted that polyurethane foams could be
5. Polyurethane foam as a sorbent in analytical chemistry 43
dissolved in hot arsenic (III) chloride solution. The inorganic impurities in different
batches of polyether and polyester polyurethane foams have been measured by
means of neutron activation analysis and found to be very low [237-239].
5.3.2
Option for separations using polyurethane foam membranes
PUF membranes can be used for separation and pre-concentration of various
inorganic and organic species in aqueous and non-aqueous media and also in
gaseous mixtures. Such applications have received considerable attention during the
last decade, i.e. PUF can function as a solid sorbent in solid-liquid and/or solid-gas
systems.
From the side of the chemical structure and properties standpoint, the options for
polyurethane foam membranes are as follows:
Untreated membranes as sorbents: The polyether or polyester type
polyurethane membranes sorb the organic compounds to be separated or
pre-concentrated base on an interaction with the polyurethane polymer itself.
Physically immobilized membrane sorbents: Suitable reagents are loaded into
the PUF membranes (precipitates or powdered water-insoluble reagents,
powdered solid ion.exchangers etc.).
Membranes modified by swelling as sorbents: In this case, the membranes are
impregnated (loaded) with hydrophobic metal chelating compounds and the sorption
is based on chelating.
Membranes modified by chemical anchoring or grafting have different metal complex
forming functional groups on the polyurethane backbone.
Based on the aforementioned options, the recent advances in different methods of
separation are collected in table 5.1, which includes separations from liquid phases
by using untreated PUF membranes and separations from liquid phases by using
impregnated PUF membranes.
5. Polyurethane foam as a sorbent in analytical chemistry 44
5.4
Mechanistic approaches to the sorption processes on PUF
The mechanism of the sorption processes of inorganic species from aqueous media
on polyether and polyester type PUF membranes have been investigated by many
authors. Bowen suggested for the sorption of Hg (II), Au (III), Fe (III), Sb (V), Mo (VI),
Rh (III) and U (VI) a solvent extraction mechanism based on a similarity between
sorption by polyether type foam membranes and by diethyl ether. These
investigations have shown that the solvent extraction mechanism, modified by
hydrogen bonding, may also explain the sorption of all organic compounds by
polyether and polyester polyurethane foam membrane [228, 229].
Bowen has envisaged that the extraction of anionic metal complexes could also be
based on a mechanism due to the PUF membranes acting as weak or strong anion-
exchangers. The possible existence of anion extraction sites arises from the
tendency of both the nitrogen atoms of the methane linkage and the ether oxygen
atoms to accept protons to afford [228]:
O
OC
O
N
H
H
C
H
NH
2
or O
H
2
CCH
2
Hence, the polyether-type PUF membranes will have anion-exchange sites of various
strengths. This mechanism may contribute significantly to the sorption of anionic
metal complexes in the presence of strong acids in high concentrations.
5.5
PUF as sorption techniques from aqueous media
Static batch media [240, 241]
The contact between PUF sorbents and aqueous solutions is realized by batch
shaking or batch squeezing (pulsation) until equilibrium is established. The former
can be carried out by simply shaking the sorbents, such as foam cubes, balls, sheets
or powder), in a stopper flask with the analyzed solution. The latter is accomplished
in a squeezing cell or in a conventional beaker.
Dynamic (flow) column method
(eq. 6)
5. Polyurethane foam as a sorbent in analytical chemistry 45
The foam cubes, balls, cylinders, or discs are packed in a conventional
chromatographic column. A widely-employed vacuum method for foam column has
been developed [242, 243].
Pulsated (Squeezing) Column Method
The foam cylinder made of resilient polyurethane is placed into a conventional glass
or plastic medical syringe so that it can be easily compressed and released by
moving the plunger [244, 245].
5.6 Using polyurethane foam for removal of organic contaminants
Unloaded and loaded polyurethane foams have been used as solid sorbents in
separation and pre-concentration of a wide variety of inorganic and organic
compounds from different media.
Gesser et al. suggested the application of PUF for the collection of trace organic
contaminants from water using a batch technique. Since then, several investigations
have been published. These describe the application of treated and untreated PUF
as collectors in separating and concentrating various chlorinated insecticides and
other organic substances [229].
Gesser et al. developed a fast and efficient method by using porous PUF to the
extraction and recovery of polychlorobiphenyls (PCB) from water [229].
5. Polyurethane foam as a sorbent in analytical chemistry 46
Ref
246
247
248
249
250
251
Determination
method
HPLC-diodearray
detection
Column
chromatography, FTE
method
Spectrophotometry
Spectrophotometry
Spectrophotometry
Gas- Liquid
chromatography
Type of solid-
liquid interaction
Column
Column and
spiking method
Batch
Batch and column
Batch and column
column
Reagent
Cyclodextrin
MeOH + DCM
5% TOA and
3% TMP in n-hexane
--
5% TBP in benzene
--
Foam type
Loaded and unloaded PUF
Loaded and unloaded PUF
Loaded and unloaded PUF
Unloaded PUF
Loaded and unloaded PUF
Unloaded PUF
Separated or
preconcentrated
species
Carcinogenic aromatic
amines
Polycyclic aromatic
hydrocarbons
A caricides; dicofol
bromopropylate
Nitrophenols
Insecticides;
azodrine, dimethoate
and lannate
Sulfur and
phosphorus
insecticides
Table 5.1: Separations from liquid phases using treated and untreated polyurethane foam (PUF) membranes
5. Polyurethane foam as a sorbent in analytical chemistry 47
ef
252
253
254
255
256
257
Determination
method
HPLC-fluorescence
detection
Column
chromatography
UV-
spectrophotometery
Liquid chromatography
( LC-ESI
+
-MS) and
mass spectrometry
Spectrophotometry
and HPLC technique
with electrochemical
detection
Colorimetrically at
610nm
Type of solid-liquid
interaction
Uncoated PUF
Column
Automatic squeezes
Batch
Batch
Batch
Column
Reagent
--
3% OV-17
--
--
--
Dithizone
Foam type
Uncoated PUF
Loaded and unloaded PUF
Unloaded PUF
Unloaded PUF
Unloaded PU pellet
Coated and Uncoated PUF
Separated or
preconcentrated
species
Polycyclic aromatic
hydrocarbons (PAH)
Some phthalate
esters
Aromatic acids and
phenols
Aromatic amines
and its derivatives
Phenols
Some trace metal ions
Table 5.1: Separations from liquid phases using treated and untreated polyurethane foam (PUF) membranes
5. Polyurethane foam as a sorbent in analytical chemistry 48
Ref
258
259
260
261
262
263
Determination
method
Mixed solvent extraction
(hexane and nonane)
GC-MS, IR and
Raman Spectroscopy
and UV-Visible
spectroscopy
GC-MS
--
Spectrophotometry
UV-Visible
spectrophotometry
Type of solid-
liquid interaction
Batch
Column
Column
SLM
Batch
Column
Reagent
TBP and hexane in ester
--
--
--
TOA
--
Foam type
Loaded and unloaded
pellets of PUF
Cyclodextrin
polyurethanes
Nanosponge cyclodextrin
polyurethanes
Polyurethane urea-
polymethylmethacylate
(PUU-PMMA)
Loaded PUF
Unloaded PUF
Separated or
preconcentrated species
Naphthols and phenol
Organic pollutants such as,
PCBs, PAHs and EDCs
Organic contaminants such
as DBPs and 2-MIB
Chlorinated volatile organic
compounds ( VOCs) such as
chloroethanes,
chloromethanes,
Phenols, such as
o-chlorophenol
o- nitrophenol
m- and o- cresol
Carbanyl
Table 5.1: Separations from liquid phases using treated and untreated polyurethane foam (PUF) membranes
5. Polyurethane foam as a sorbent in analytical chemistry 49
Farag and Shatiawi, have used unloaded PUF columns to separate some organic
insecticides. It is a comparative study of the extraction and recovery of some
insecticides (azodrine, dimethoate and lannate) from aqueous media. This method
can be used to preconcentrate insecticides in tap water and modified to determine
dissolved insecticides in industrial and natural waters [250].
El-Shahawi et al. achieved successfully the preconcentration and separation of some
acaricides and nitrophenols by using polyethether based PUF [248, 249].
Dmitrieko et al. demonstrated that the preconcentration of phenol compounds by
adsorption on PUF as ion pairs of 4-nitrophenylazophenolates with the
cetyltrimethylammonium cation [256]. Marand and Schumack et al. used PUF to
determine aromatic organic compounds [244, 255]. And Sukhanov et al. have studied
the extraction of phenol and naphthols with isomolar mixtures of nonane and
tributylphosphate (TBP) into PUF [258].
Dmitrienko et al. have developed a technique for the sorption preconcentration of
various ion associates on PUF [252].
Gough and Gesser, porous PUF was successfully used to remove some phthalate
ester from water at the part per million level [253].
They have also studied the sorption of various ion associates on PUF; the results of
studying were generalized. The main sorption-affecting factors were found to be the
nature, hydrophobicity, and charge of the associate ion [242].
Das et al. have removed chlorinated volatile organic contaminants from water by
prevaporation using a novel polyurethane urea-poly(methylmethacrylate) [261].
EL-Shahawi has utilized technique applying unloaded and polyester-based PUF
loaded with tri-n-octylamine (TOA) in the removal of phenols from water [262].
Cassella et al. have developed an analytical method for carbaryl in waters after its
preconcentration onto a polyether-type PUF followed by on-line elution [263].
6. Novel block copolymers 50
6. Novel block copolymers
6.1 Synthesis and structure of membranes
The role of 1,1 – diphenylethylethylene in radical polymerization is still not yet
understood in all details today. 1,1 – diphenylethylethylene (DPE) is well known for its
inability to undergo homopolymerization, but it can participate in radical
copolymerizations [264-268]. The participation of DPE in radical polymerization leads
to the formation of stable DPE radicals (Scheme 6.1) by resonance stabilization of
the radical by the two phenyl group and a strong steric hindrance for the addition of
any other monomer. Thus, DPE has drastic effects in radical polymerization.
Controlled radical polymerization (CRP) has become one of the most rapidly growing
topics in the field of polymer research in the last decade of the 20
th
century [269-272].
The use of CRP strategies in aqueous hetero phase polymerization techniques is
nowadays an actual topic of polymer research as it potentially promises to be of
enormous practical importance [273, 274].
In order to understand the influence of monomer structure and radical stability on free
radical copolymerization, DPE was frequently chosen as a model monomer.
Copolymerizations of DPE with various vinyl and acrylic monomers like acrylonitrile
(AN) [275], methacrylonitrile (MAN) [276], methyl acrylate (MA) [220],
methylmethacrylate (MMA) [220], have been studied.
The calculated reactivity ratios of DPE with almost all co-monomers confirmed the
impossibility of DPE to homopolymerize. These results confirm that DPE acts as
retarder during radical co-polymerizatios and hence, DPE was also frequently used in
radical polymerization in order to control the molecular weight.
Scheme 6.1: Formation of PMMA-chain with a terminal DPE radical
6. Novel block copolymers 51
Recently, another method of controlling radical polymerizations based on 1,1-
diphenylethylene (DPE) has gained some interest [274-276]. Typically, CRP is
characterized by the two features of livingness regarding multi lock co-polymer
formation. The mechanism of this kind of polymerization, especially the formation of
block copolymers, is rather unclear although the block structure of the copolymers
obtained at the end of the second step polymerization was proved.
More recently, DPE was used to carry out controlled radical polymerization of styrene
and other vinyl monomers in bulk [276]. The resulting DPE precursor copolymers
were subsequently employed to prepare block copolymers. The authors describe the
molecular structure of the DPE copolymers as a result of combination termination
either between two polymeric radicals terminated with DPE and styrene radicals
[275].
6.1.1 Novel polymeric membrane based on diphenylethylene
Novel types of polymer compounds which have been created at the University of
Paderborn, which were used as open cell solid membrane five types of polymer
membranes denoted as BM32, BM34, BM40, BM42 and BM43 [276]. Figure 6.1
shows typical polymers in which the bubbles (cells) occupy 97% of the volume. The
compositions of polymer membrane are described below and their substructures are
shown in figure 6.1.
Fig. 6.1: a) Scanning electron-micrographs of a typical BM structure 1. 5
.
10
-3
g
(HAc)/ml, b) Layer structure of polymer membrane [276]
b
6. Novel block copolymers 52
O
N
H
O
diacetonacrylamide
CH2
diphenylethylen
CH
3
CH
2
OOH
O
hydroxyethylmethacrylate
OH
O
acrylic acid
6.1.2 Composition of polymer membrane foam
Novel block copolymer membranes were synthesized at the University of
Paderborn by Dr. B. Weber (Chemistry and Technology of Coatings, Head of
the group: Prof. Dr. W. Bremser).
The composition and substructures of the novel block copolymer compounds
used are as listed below:
BM 32: 97% acrylic acid and 3% diphenylethylene
BM 34: 3% diphenylethylene, 49% hydroxyethylmethacrylate, 24% acrylic acid,
and 24% diacetonacrylamide
BM 40: 60% acrylic acid, 37% diacetonacrylamid and 30% diphenylethylene
BM 42: 3% diphenylethyelene and 97% hydroxyethylmethacrylate
BM 43: 3% diphenylethylene, 48.85% hydroxyethylmethacrylate and 48.5%
methylmethacrylate.
Figure 6.2: Monomers of polymer membrane compounds investigated
7. Results and discussion – polyurethane membrane 53
7 Results and discussion – polyurethane foam
7.1 Methodical approach
This study is divided into five parts:
First, the metabolite ASFM was synthesized according to the methods described in
the literature [277-279]. In the second part, four types of polyether or polyester-based
polyurethane foams with different pore sizes were used comparatively to extract the
target drugs and metabolites (CBZ, SFM and ASFM) from water. In the third part, five
types of novel block copolymer membranes were applied to investigate the
extractability of IBU, DCF, CBZ, SFM, TC, CTC and its metabolite iso-CTC. In the
fourth part, the extraction of selected drugs and some of their metabolites by
polyurethane and polymer membrane in the liquid systems was investigated (amount
loaded on membrane cubes, amount eluted from loaded membrane). In the fifth part,
analytical methods were developed after membrane recoveries with some mixture
solvents (elution of the analytes from loaded membrane cubes) and HPLC-UV was
used to determine the selected drugs and some of their metabolites in water.
7.1.1 Chromatographic methods
High performance liquid chromatography (HPLC) utilising an ultraviolet (UV) detector
has been applied for the routine analysis of antibiotics. This technique has been
more accepted than gas chromatography (GC) because the latter is complicated,
time consuming and require suitable volatile derivatives. Moreover, it seems quite
difficult to develop a universal derivatization procedure suitable for the whole analyte
group, because they show different properties in relation to the number and kind of
functional groups. However, when the peak of a target antibiotic has appeared on the
LC chromatogram, HPLC-UV methods lack qualitative information being necessary to
ensure the identification of the observed peak [280, 281]. In 2002, the European
Commission presented the Commission Decision 2002/657/EEC that states:
“methods based only on chromatographic analysis without the use of molecular
spectrometric detection are not suitable for use as confirmatory methods” [280, 282].
On such a way, High performance Liquid Chromatography coupled to a mass
7. Results and discussion – polyurethane membrane 54
spectrometer (HPLC-MS) is the ideal technique to separate, identify and quantify
several chemical compounds. It has been used to analyze antibiotics in food and
some environmental samples such as: soil [284, 285], tissues [285], urine [286, 287],
surface and river water [288, 289], hospital sewage water [290] and wastewater
treatment plants [291]. The application of the HPLC-MS technique is mostly by the
use of solid phase extraction (SPE) for clean up and/or preconcentration of analytes
from the matrix. Under these conditions, absolute limits of quantitation (LOQ) for
diclofenac (DCF) and ibuprofen (IBU) in wastewater treatment plants were 20 ng/L
for both analgesics [291].
7.2 Extraction of drugs and metabolites by PUF
7.2.1 Materials and methods
In this study two metabolites were investigated, the first was sulfamethoxazole N-4-
acetylsulfamethoxazole (ASFM), which was synthesized as shown in section 11.1,
[277-279]. The identification of the compound was confirmed by IR,
1
H-,
13
C- NMR
and mass spectroscopy (see section 11.9). Iso-chlortetracycline (iso-CTC) metabolite
of chlortetracycline, the second metabolite studied, is commercially available.
7.2.2 Polyurethane types used
Different types of PUF of density 30 kgm
-3
with 10
-2
cell /linear were employed,
provided by Eurofoam Deutschland GmbH, (Troisdorf, Germany), both are open-cell
polyether and polyester-types (see Table and Photo 7.1).
Sorption procedure
Pieces of PUF membranes (pore sizes 100, 50 and 10 µm) were pretreated as
described in (section 11.1.2) and equilibrated with aqueous solutions of individual
drugs.
Aliquots were taken at intervals and analysed using HPLC-UV methods.
7. Results and discussion – polyurethane membrane 55
Table 7.1: Types of selected Polyurethane Foams
Symbol
Coade
number
Pore size [µm]
Type of foam
a
TM23450 100 (crude) polyether-polyurethane
b
TM23280 50 (middle) polyether-polyurethane
c
TM23190 10 (fine) polyether-polyurethane
d
TM23100 10 (fine) polyester-polyurethane
P
h
o
t
o
7
.
1
:
S
Photo 7.1: Selected types of polyurethane foams (a) 100 µm, b) 50 µm, c) 10 .
µm, d) 10 µm)
.
Determination of ASFM, SFM and CBZ by HPLC
Stock solutions of target drugs (1.0 mg/mL) were prepared in methanol. A series of
standard solutions for calibration in the range of 1-7 mg/L were prepared by diluting
appropriate volumes of the stock solution with ultrapure water. Table 7.1 summarizes
the volumes of the aliquots of stock solution applied.
Table 7.2: Standard solutions of target drugs in total volume of 10 mL and n= 3
β
[ mg/L]
1
2
3
4
5
6
7
V [µL]
10 20 30 40 50 60 70
c)
d)
a)
b)
7. Results and discussion – polyurethane membrane 56
Figure 7.1 shows the calibration curve of the target drugs. The chromatograms are
recorded in figure 11.3. The standard solutions were injected into the
chromatographic system described in section 11.3.1.
Fig. 7.1: Calibration curve of target drugs (CBZ, SFM and metabolite ASFM)
7.3 Extractability of ASFM, SFM and CBZ by PUF
Preliminary experiments established that 6 h of contact between PUF and a drug
solution on the shaking machine was generally sufficient to reach equilibrium. At the
end of this time, solution samples were taken to determine the degree of sorption on
the PUF. By taking into consideration the equilibrium concentration (β
s
) of the
selected compounds and the initial concentration (β
o
) before contact with the PUF,
three parameters were calculated: The percentage of drug extraction (% E), the
distribution coefficient (D) and the recovery (% R) [261].
%E = 100 (β
o
– β
s
) / β
o
(eq .7)
D = (V
.
E ) / W (100 - E) (eq .8)
%R = E (V
R
/ V
E
)
.
100 (eq .9)
% E = percentage of drug extraction
% R = percentage of drug recovery
y = 0,8215x + 0,02
R2= 0,9993
y = 1,0223x - 0,0123
R² = 0,9992
y = 2,501x + 0,4144
R² = 0,9988
0
5
10
15
20
25
02468
Peaks area mAu*min
Concentration mg/L
ASFM
SFM
CBZ
7. Results and discussion – polyurethane membrane 57
D = distribution coefficient
β
o
= initial concentration of the solution
β
s
= concentration of the solution in equilibrium time
V = volume of the solution (ml)
W = mass of the foam (g)
V
R
= volume of eluent
V
E
= initial volume of extraction solution
The distribution coefficient (D) is the ratio of the concentration of drug on the foam
and in solution. When it becomes constant, the sorption process has reached
equilibrium.
7.3.1 Sorption of ASFM- Effect of shaking time and of PUF- type
The developed HPLC-UV method (I) has been used as described in section 11.8.
The effect of extraction time on the loaded amount of compound ASFM by PUF was
investigated for 1, 2, 3, and 6 hours. The maximum extraction was obtained after 3
hours. Afterwards, the extraction yields seemed to be constant. Therefore, a time
interval of 3 h was chosen for further experiments as illustrated in figure 7.2.
To identify the conditions for the maximum sorption by several types of PUF, samples
of the polymer were loaded with pharmaceuticals and the results compared. The
results are shown in table 7.3. The most striking difference in performance is that
between the polyether-based foam A and the other foams. This hypothesis is further
substantiated by comparison of foam types C and D. The sorption of foam types
increases with increasing polyether content for the ASFM metabolite. For instance,
the D values for ASFM are 86 and 186 for polyester -PUF (D) and polyether-PUF (A),
respectively. Hence, the more polar compound ASFM appears to be somewhat better
sorbed by polyether foam than by polyester foam (see table 7.3 and figure 7.2).
Chow reported similar conclusions of the sorption of organic dyes by PUF [292].
7. Results and discussion –
polyurethane membrane
Table 7.3:
Effect of PUF types and equilibrium time on sorption of ASFM
(V
E
: 100 mL, β
o
: 3 mg/L, 0.500
Fig. 7.2:
Effect of PUF types on sorption of ASFM (for conditions see table 7.3)
a)
Sorption of ASFM as a function of time
b)
Maximum sorption yields by different foam types (3 h)
Type of
PUF
A
Time, h
%E
D
1
20.50 51.6
2
40.52 136.1
3
48.24 186.1
4
46.92 176.5
5
45.78 169.1
6
45.60 148.4
a)
b)
polyurethane membrane
Effect of PUF types and equilibrium time on sorption of ASFM
: 3 mg/L, 0.500
±0.002 g dry foam 1cm
3
, n = 3)
Effect of PUF types on sorption of ASFM (for conditions see table 7.3)
Sorption of ASFM as a function of time
Maximum sorption yields by different foam types (3 h)
B
C
%E
D
%E
D
%E
21.44 54.6 27.90 74.9
25.73
27.48 75.9 28.82 65.9
26.34
33.93 102.7 33.45 100.3
30.44
32.50 96.3 32.42 99.2
30.30
32.82 97.6 33.01 98.5
30.33
30.21 50.6 32.62 42.7
30.30
58
Effect of PUF types and equilibrium time on sorption of ASFM
, n = 3)
Effect of PUF types on sorption of ASFM (for conditions see table 7.3)
D
D
25.73
70.3
26.34
70.0
30.44
86.3
30.30
87.0
30.33
87.1
30.30
87.0
7. Results and discussion – polyurethane membrane 59
From figure 7.2- a), it can be seen that the equilibrium of the extraction processes for
all types of PUF are reached after three hours. Figure 7.2- b), shows that the best
extraction yield for ASFM is achieved by foam type A (polyether-PUF). The extraction
yields in descending order, are A > B ≥ C ≥ D. In general, the polyether-PUF foam
type has better sorption efficiency than the polyester-PUF foam type D. Moreover,
the large pore size of PUF-type A seems to favor the extractability of ASFM.
Sorption mechanism
For the extraction of organic molecules by PUF, the most commonly proposed
mechanism is solvent extraction, also referred to as phase distribution. In this
mechanism the foam acts simply as a solid phase organic layer, into which the
analyte is diffused [261]. The experimental results shown in table 7.3 and figure 7.2
agree well with the above discussion.
Werbowesky and Chow concluded that the extraction of organic compounds occurs
by an ether-like solvent extraction mechanism, and that there was no evidence of a
mechanism requiring ionic species. In addition, they found that hydrogen bonding
was a significant factor in the extractions, and that compounds containing phenolic or
carboxylic groups were extracted better with polyether-type polyurethane. The
preference for polyether-type foam was attributed to its ability to form stronger
hydrogen bonds than those formed with polyester-type foam [241].
Based on the above discussion, it is clear that the percentage of ASFM extraction by
polyether -type PUF (34%) is higher than the extraction percentage with polyester-
type (30%). It is worth noting that both foams C and D have the same pore size (10
µm, see table 7.2).
7.3.2 Effect of pH on the sorption
Experiments were carried out by placing 1 cm
3
foam cubes of type polyether-based
PUF into 100 mL solutions of CBZ, SFM and the metabolite of the latter ASFM, and
pH- values of 3, 7 and 9 were adjusted as described in section 11.5. The mixture
solutions were shaken for 270 min to ensure equilibrium. The foam cubes were
separated and the amount of each analyte that remained in solution was measured
by the HPLC-UV technique (method I). The results given in table 7.4 and figure 7.3
represent the individual extraction profiles as a function of time and of pH values.
7. Results and discussion – polyurethane membrane 60
Table 7.4: Influences of pH and extraction time on sorption of selected drugs
(V
E
: 100, mL, β
o
: 3 mg/L, 0.500±0.002 g dry foam cubes1 cm
3
, n = 3)
Obviously, the effect of pH is most pronounced in the case of SFM. Scheme 7.1
shows the SFM ionic forms in both acidic and alkaline media.
Scheme 7.1: Expected forms of SFM in basic and acidic media
Time,min
%E, pH 3
%E, pH 7
%E, pH 9
CBZ
SFM
ASFM
CBZ
SFM
ASFM
CBZ
SFM
ASFM
10
92.4 71.9 36.6 50.1 32.8 40.1 56.1 68.0 36.2
30
63.1 72.9 56.1 50.6 42.6 54.8 59.5 69.3 58.2
60
65.1 74.2 58.9 54.2 43.9 58.2 59.7 73.4 60.7
90
71.2 75.2 66.5 56.9 45.6 65.3 60.2 75.1 62.0
120
72.2 78.5 71.5 64.5 46.1 67.9 62.6 76.3 65.5
150
75.7 79.1 71.1 58.3 50.4 68.2 68.4 77.3 66.7
180
79.0 79.9 71.2 69.8 54.4 69.2 70.8 77.1 66.9
210
77.4 77.5 71.9 67.8 50.1 59.6 70.1 75.0 65.0
240
77.4 75.8 71.7 68.8 51.2 59.9 70.1 75.3 65.3
270
77.5 74.8 72.0 69.8 50.8 58.6 70.2 74.9 65.5
(a)
(b)
7. Results and discussion –
polyurethane membrane
Fig. 7.3:
Influence of pH on the extraction of target compounds by PUF
a)
CBZ, b) SFM, c) ASFM, (Extraction co
Fig. 7.4:
Effect of pH on the sorption of drugs by PUF (t
0
20
40
60
80
%E
0
20
40
60
80
100
0
%E
0
20
40
60
80
100
0
60
%E
0
20
40
60
80
100
0
%E
b)
a)
c)
polyurethane membrane
Influence of pH on the extraction of target compounds by PUF
CBZ, b) SFM, c) ASFM, (Extraction co
nditions see table 3.7)
Effect of pH on the sorption of drugs by PUF (t
E
: 3 h, β
o
: 5 mg/L, n = 3)
pH 3 pH 7 pH 9
CBZ
SFM
ASFM
60 120 180 240 300
Time, min
CBZ
pH 3
pH 7
pH 9
60
120 180 240 300
Time, min
SFM
pH 3
pH 7
pH 9
60 120 180 240 300
Time, min
ASFM
pH 3
pH 7
pH 9
61
Influence of pH on the extraction of target compounds by PUF
nditions see table 3.7)
: 5 mg/L, n = 3)
7. Results and discussion – polyurethane membrane 62
The pH of a chemical solution is an important parameter to study this system
because the formation of the interaction between PUF foam and pharmaceutical
compounds is strongly dependent on the hydronium or hydroxide ion concentration in
the media. The sorption of different ion associates by PUF with different loaded and
unloaded specifications of the selected compounds has been noted [293]. It was
found that the sorption of ion associates of the selected compounds by PUF is
affected by the hydrophobicity and charge of associated ions, by the nature and
concentration of the counter ion, by the structure of the polymer units of polyurethane
foams and by the acidity and alkalinity of the chemicals dissolved in the aqueous
phase. It was noted, that the formation of hydrogen bonds between the protonated
amino group (SFM, ASFM and CBZ) and the polyether oxygen atoms of PUF is most
probable, (see scheme 7.2, table 2.1, and Equations 4 and 5 for the structure of
selected compounds and of PUF).
Scheme 7.2: Model of sorption of polar acidic drugs by PUF
Possible extraction mechanisms
The data in table 7.4 and in figure 7.3 indicate that the composition of the aqueous
phase affects the sorption of ion associates for at least two reasons. First, the
compounds studied can occur in two different forms which depend on the pH of the
media as indicated in scheme 7.1 [240]. Second, when the acidity of the solution and
the composition of the salt composition changed, the sorption properties of PUF
could be varied due to the modification caused by the hydroxonium ions on sorption
properties (see scheme 7.2). To describe the sorption behavior of associates on
polyurethane foams, the following system of equilibrium (considered for R
+
X
-
associates as an example) is used:
In aqueous solution
In elution solvent
In polymer membrane
7. Results and discussion – polyurethane membrane 63
Where R
+
is a large hydrophobic cation and X
-
is a counter ion (Cl
-
or OH
-
), (see
scheme 7.1-b)
R X RX K RX
R X
ac RX
+ −
+ −
+ ⇔ =
,[ ]
[ ][ ]
,
(eq. 10)
R X RX K RX
R X
f f f ac RX
ff
f f
+ −
+ −
+ ⇔ =
( ) [ ]
[ ] [ ]
, ,
(eq. 11)
R X R X K R X
R X
f f RX
f f
+ − + −
+ −
+ −
+ ⇔ + =
,[ ] [ ]
[ ][ ]
(eq. 12)
where [RX]
f
, [R
+
]
f
, [X
-
]
f
, [R
+
], and [X
-
] denote the concentrations of the ion associate
and of the ions in the polyurethane foam phase (f) and water, K
ac,RX
and
K
ac RX
f
,
are
the equilibrium constants of RX association in water and the polyurethane foam
phase, respectively; K
D,RX
is the coefficient of RX partition between the phases; and
K
RX
is the sorption constant. The partition coefficient (D) of associate RX, after the
corresponding transformations of equations. 10 and 12 and with the condition of
electric neutrality [R
+
]
f
= [X
-
]
f
, becomes:
DRX R
RX R
K K X
K K R
K K R X
K X
f f D RX ac RX
ac RX
fRX
ac RX
fRX
ac RX
=+
+= × +
+
+
+
−
+
+ −
−
[ ] [ ]
[ ] [ ]
[ ]
[ ]
( [ ] [ ] )
( [ ])
, ,
,
,
,
12
1212
121212
1
1
(eq. 13)
The equation for the partition coefficient is simplified in the case when the ion
associate is completely dissociated in both the aqueous solution and the
polyurethane foam phase:
D K X R
RX
=
− + −
121212
[ ] [ ]
(eq. 14)
When associate RX is completely dissociated in water but not dissociated in the
polyurethane foam phase, the partition coefficient is:
D K K X
RX ac RX
f
=
−
,
[ ]
(eq. 15)
Equations 14 and 15 show that the partition coefficient (D) at a constant
concentration of cation R
+
should increase with the concentration of counter ion X
-
,
and with the slope of the complete dissociation of RX in the PUF phase. The partition
coefficient of cation R
+
in the form of associate RX does not depend on its
7. Results and discussion – polyurethane membrane 64
concentration in the absence of dissociation in the PUF phase and decreases in its
presence when the R
+
concentration increases. At a constant concentration of X
-
,
which is maintained by the addition of any non- sorbed salt MX, the slope of log D as
a function of log [R
+
]
will be – 0.5 at the complete dissociation of the ion associate in
the PUF phase [240].
7.3.3 Effect of salts on the sorption
The effect of various concentrations of chloride salts, such as K
+
, Na
+
, NH
4+
and
Mg
2+
, and of the types of PUF on the sorption behavior at the optimum conditions has
been studied.
Representative results are given in fig. 7.5, which shows the sorption yields of
selected drugs. They increase slightly in the presence of cations in the following
order: Na
+
≈ NH
4+
> K
+
≈ Mg
2+
.
Fig.7.5: Influence of salts on target drug extraction (pH 3, V
E
: 100 mL, 0.1mol/L,
β
o
: 3 mg/L, 0.500±0.002 g of dry foam (1 cm
3
), n = 3)
The addition of salts increased the sorption efficiency of the tested species into the
foam by reducing the number of water molecules available to solvate the drugs
compounds. They would then be forced out of the solvate phase into the foam since
some amount of (free) water molecules is preferentially used to solute the added
ions. Hence, the influence of the salts can be explained by the salting out effect on a
solvent-extraction mechanism [246, 252]. Fig. 7.6 shows the effect of ionic radii of
various metal cations on the sorption of ASFM.
0
20
40
60
80
100
water KCl NaCl NH4Cl MgCl2
CBZ
SFM
ASFM
%E
water KCl NaCl NH
4
Cl MgCl
2
7. Results and discussion – polyurethane membrane 65
Fig. 7.6: Effect of ionic radii of various metal cations on the sorption of ASFM
(K
+
: 1.4 Å, Na
+
: 1.0 Å, Mg
2+
: 0.7 Å)
From the sorption studies carried out, it can be concluded that the best extraction
result conditions for CBZ, SFM and ASFM were observed at pH 3 in the presence of
0.1 M NaCl, after a 3 h shaking period (as mentioned above in figures 7.3 and 7.5);
the yields of extraction for these target compounds are 94%, 98% and 98% for CBZ,
SFM and its metabolite ASFM, respectively (see table 7.5).
Table 7.5: Loaded amounts on PUF at pH 3 (diluted HCl, 0.1M NaCl, V
E
: 100 mL,
t
E
: 3 h, 0.500±0.002g of dry PUF (1cm
3
), β
o
: 5 mg/L, n = 3)
7.3.4 Recovery of drugs from loaded PUF
Acetone and acetonitrile were employed to elute each loaded drug (CBZ, SFM and
ASFM) from PUF -cubes. The recovery procedure is described in section 11.6.1 and
shown in figure 7.7.
The results obtained are displayed in table 7.6 and figures 7.8 and 7.9.
0
0,5
1
1,5
2
log D
Drugs
β
s
[mg/L]
Loaded
amount [µg]
Loaded amount
[µg/g per 1g of PUF]
CBZ
0.3 470 940
SFM
0.1 490 980
ASFM
0.1 490 980
K
+
Na
+
NH
4+
Mg
2
+
Metal cations
7. Results and discussion –
polyurethane membrane
Table 7.6:
Recovery percentage of target drugs from PUF cubes with various
eluents, (t
R
: 1 h, V
Eluting solvents
Acetone
Acetonitrile
Fig. 7.7:
Extraction and recovery procedures
polyurethane membrane
Recovery percentage of target drugs from PUF cubes with various
: 1 h, V
R
: 30mL, V
S
: 500 µL, n = 3)
Eluting solvents
CBZ
SFM
ASFM
Acetone
83 79
76
Acetonitrile
75 69
67
Extraction and recovery procedures
by means of PUF
66
Recovery percentage of target drugs from PUF cubes with various
ASFM
76
67
7. Results and discussion –
polyurethane membrane
Fig 7.8:
Influence of shaking time on the recovery of target drugs from PUF loaded
with various eluting agents,
t
R
: 1h, n = 3)
Fig. 7.9:
Extraction and recovery of drugs with different solvent from PUF,
a) Acetone, b) Acetonitrile,
The amounts of ASFM, SFM and CBZ which eluted f
listed in table 7.7. Table 7.8 summaries the total mass of each extracted and
recovered target compound.
60
70
80
90
100
0 40 80
120
Recovery (%)
Time, min
Acetone
a)
0
20
40
60
80
100
ASFM SFM
CBZ
(%)
Target drugs
Acetone
a)
polyurethane membrane
Influence of shaking time on the recovery of target drugs from PUF loaded
with various eluting agents,
a) Acetone, b) Acetonitrile, (V
R
Extraction and recovery of drugs with different solvent from PUF,
a) Acetone, b) Acetonitrile,
(V
R
: 30 mL, V
E
: 100 mL, t
E
: 3 h, t
R
The amounts of ASFM, SFM and CBZ which eluted f
rom loaded PUF cubes are
listed in table 7.7. Table 7.8 summaries the total mass of each extracted and
recovered target compound.
120
160
ASFM
SFM
CBZ
60
70
80
90
100
0 40 80 120
160
Recovery (%)
Time, min
Acetonitrile
b)
b)
CBZ
Target drugs
%E
%R
0
20
40
60
80
100
ASFM SFM CBZ
(%)
Target drugs
Acetonitrile
b)
67
Influence of shaking time on the recovery of target drugs from PUF loaded
R
: 30 mL,
Extraction and recovery of drugs with different solvent from PUF,
R
: 1 h, n = 3)
rom loaded PUF cubes are
listed in table 7.7. Table 7.8 summaries the total mass of each extracted and
160
200
ASFM
SFM
CBZ
%E
%R
7. Results and discussion – polyurethane membrane 68
Table 7.7: Amounts of target drugs eluted from loaded PUF cubes (β
o
: 5 mg/L, V
R
:
30 mL, t
E
: 3 h, t
R
: 1 h, n = 3)
Target
drugs
Loaded
amount at
100 %
Concentration in eluent
[mg/L]
Total amount eluted [µg]
acetone
acetonitrile
acetone
acetonitrile
ASFM
13.27 1.18 1.64 118 164
SFM
11.23 0.82 1.24 82 124
CBZ
12.77 1.06 1.52 106 152
Table 7.8 (A and B): Total mass of target drugs extracted and recovery
(β
o
: 5 mg/L, V
E
: 100 mL and V
R
: 30 mL)
A: Extraction of drugs from aqueous solution by 0.50 g PUF at pH 3 (0.1M NaCl,
t
E
: 3 h, n= 3, washing 3*10 mL of bidistilled water, V= 100 ml)
B: Optimum recovery with acetone (t
R =
1 h)
Target
drugs
Total mass
adsorbed
[µg]
β
s
[mg/L]
Eluted per 0.5 g
PUF
Total mass
remaining
[µg]
%R
ASFM
490 4.85 291 60
SFM
490 4.83 290 59
CBZ
470 4.10 246 52
The data indicate that the extraction yield of target drugs decreases in the order
ASFM = SFM > CBZ. This order correlates with the polarity and acidity of these
compounds, whereas the yield recovery with acetone increases in the order
Target
drugs
β
o
[mg/L]
Total mass
[µg/100mL]
β
s
[mg/L]
Total mass
remaining
[µg]
Total mass
adsorbed [µg]
%E
ASFM
5.00 500 0.1 10 490 98
SFM
5.00 500 0.1 10 490 98
CBZ
5.00 500 0.3 30 470 94
7. Results and discussion – polyurethane membrane 69
ASFM > SFM > CBZ. This fact can be explained by the combination of a solvent
extraction mechanism and the hydrophobic character of PUF.
Conclusion
The metabolite ASFM was synthesized and characterized by IR,
1
H-,
13
C- NMR and
mass spectroscopy (see section 11.1).
The polyurethane foam that is available is not a pure material and usually contains a
variety of reagents and additives to enhance its commercial use.
Considerable care was taken to remove any loosely-held organic and inorganic
substances as described in section 11.3.2.1.
PUF membranes were tested by contact with SFM, ASFM and CBZ. PUF-type A had
the maximum extractability. The drugs concentractions were determined by HPLC-
UV, as described in section 11.8.1. Certain open -cell solid sorbent membrane
compositions were tested in batch processes. Different factors were studied to find
the best extraction conditions:
pH 3, adjusted by using 0.1 mol/L HCl
0.1 mole/L NaCl to adjust ionic strength
Optimum time of extraction: 3 hours
This condition extraction rates of 98% for ASFM and SFM and 94% for CBZ from the
solution at a concentration of 5 mg/L.
Different factors were studied to find the best recovery conditions for these drugs and
metabolite from loaded PUF-cubes membrane:
Acetone as elut
Time of recovery: 1h
This condition gave recovery yields of 60% for ASFM, 59% for SFM and 52% for
CBZ.
The investigation shows that this method is suitable for removal of these drugs and
this metabolite from aqueous solution.
On this basis the PUF membrane is a good membrane to use for sampling and
sample preparation.
7. Results and discussion – polyurethane membrane 70
7.4 Sorption of Tetracyclines (TCs) by PUF
7.4.1 Influence of pH media on the sorption of TCs by PUF
The pH value of a drug's solution is an important parameter to study in this system
because the sorption depends on the ions in the media to make hydrophilic or
hydrophobic forms in the solution [293, 294].
Tetracyclines are amphoteric molecules with multiple ionizable functional groups
(Tables 2.1 and 2.2) that exist predominantly as zwitterions at pH values typical of
the natural environment. These zwitterions tend to aggregate in aqueous and
aqueous mixed solvent solutions with increasing aggregation in the presence of
divalent cations [134]. At alkaline pH values (pH > 7) the hydroxylgroup (pK
a2
)
becomes increasingly more negative and the amino group (pK
a3
) begins to
deprotonate. Furthermore, chlortetracycline (CTC) in media with pH less than 1.5
transforms to anhydrochlortetracycline (anhydro-CTC). At media > pH 8 CTC
converts into iso-chlortetracycline [295] as shown in scheme 7.3. Acidic media (pH 3)
and neutral media (pH 7) were therefore selected for use in these sorption studies.
Scheme 7.3: Properties of chlortetracycline in acidic and basic media [295]
7. Results and discussion – polyurethane membrane 71
As shown in figure 7.10, the extraction of each TC, CTC and iso-CTC were
investigated in aqueous solutions of different pH (non-buffered water, pH 3 and
pH 7). Section 11.5 depicts the applied procedure and the HPLC-UV method V that
was used to determine each residual amount of analyte in presence of PUF.
As shown in figure 7.10, the highest extraction-yield was determined for CTC and iso-
CTC (56% and 60% extracted). By comparing the results presented in figures 7.10
and 7.11, it is obvious that the optimium sorption conditions prevail at pH 3. The
degree of extraction increased with increasing sorption time, until equilibrium was
reached after 3 hours. The general order of extraction efficiency of the target drugs
was: CTC > iso-CTC > TC, which is opposite, of the order of polarity [296]. Figure
7.11 also demonstrates that the tetracyclines were extracted in the following order of
pH-values: pH 3 >> pH 7>> water.
It was noted, that the formation of hydrogen bonds between the protonated amino
groups and carboxylic acidic groups of selected drugs and the polyether oxygen
atoms of PUF is quite probable, (table 2.1, Equations 4 and 5 for the structure of
selected compounds and of PUF).
7. Results and discussion –
polyurethane membrane
Fig.7.10:
Effect of pH and time on extraction of TCs by PUF, a) TC, b) CTC,
c) iso- CTC (V
E
: 100 mL,
Fig.7. 11:
Effect of pH on extraction of tetracyclines (t
20
40
60
80
%E
0
20
40
60
80
0
%E
0
20
40
60
80
0
%E
0
20
40
60
80
0
%E
b)
a)
c)
polyurethane membrane
Effect of pH and time on extraction of TCs by PUF, a) TC, b) CTC,
: 100 mL, β
o
: 3 mg/L, 0.500±0.002
g of dry foam (1 cm
Effect of pH on extraction of tetracyclines (t
E
: 3 h, β
o
: 3 mg/L, n = 3)
0
20
40
60
80
TC CTC iso-CTC
pH 3
water
pH 7
2 4 6 8
Time, h
TC
water
pH 7
pH 3
2 4 6 8
Time, h
CTC
water
pH 7
pH 3
2 4 6 8
Time, h
iso-CTC
water
pH 7
pH 3
72
Effect of pH and time on extraction of TCs by PUF, a) TC, b) CTC,
g of dry foam (1 cm
3
), n = 3)
: 3 mg/L, n = 3)
pH 3
water
pH 7
7. Results and discussion – polyurethane membrane 73
Conclusion
PUF membranes (type A, polyether-polyurethane, density 30 kgm
-3
and pore size
100 µm) functioning as open cell solid sorbents membrane was tested by contact
with the drugs TC, CTC and metabolite iso-CTC. The quantification of drugs traces
were achieved by the HPLC-UV technique as shown in section 11.8.2. The PUF
cubes membrane compositions were tested in batch experiments. Various factors
such as the effect of time and of pH media on a drug's solution were tested to
determine the best extraction conditions for these drugs and this metabolite:
pH 3, adjusted by using 0.1 mol/L HCl
Optimum time of extraction: 3 hours
This condition gave 56 % of TC, 64 % of CTC and 60 % of iso-CTC from the solution
at a concentration of 3 mg/L.
Solutions with pH 3, pH 7 and non- buffered water were applied to determine the
influence of pH-values on the sorption of TC drugs. CTC is not stable at pH 9. It
converts to the metabolite iso-CTC as explained in section 7.4.1 and shown in
scheme 7.3 [301].
The polyurethane foam (PUF) membrane has been applied quite to the extraction of
the drugs SFM, CBZ, TC and CTC and metabolites ASFM and iso-CTC from
aqueous media. It can be seen that PUF is a suitable membrane for the pre-
concentration and separation of TC drugs from aqueous solutions.
8. Results and discussion – Block copolymer membranes 74
8 Sorption of drugs by novel block copolymer membranes (BM)
In this section, novel types of block-copolymer compounds created at the University
of Paderborn [276], were used as open -cell solid membranes, to extract the active
drugs, ibuprofen (IBU), diclofenac (DCF), carbamazepine (CBZ), sulfamethoxazole
(SFM), tetracycline (TC), chlortetracycline (CTC) and its metabolite iso-
chlortetracycline (iso-CTC), from aqueous media. Five types of polymer membrane
were selected, denoted as BM32, BM34, BM40, BM42 and BM43. The compositions
of these membranes are described in section 6.1.1 and their substructures are shown
in figure 8.1.
8.1 Extractability of polymer membranes for SFM, CBZ, DCF and IBU
The pretreatment of the polymer membranes is described in section 11.3.2. To
investigate their sorption properties, 0.50 g of (0.5 cm
3
) of clean and dry cubes were
suspended in 10 mL solution containing 1.0 mg/L of each target drug. These were
shaken mechanically until sorption equilibrium was achieved. The amount of drugs
remaining in the aqueous solution was determined by the HPLC-UV technique.
Method (III) was applied as mentioned in section 11.8. Yields of extraction and
recovery were calculated from analytical data as described in section 7.3.
Table 8.1 shows the extraction yields that were determined. As presented by the data
in figure 8.2, the maximum extraction was achieved for IBU. The extraction
percentages for IBU are 82%, 88% and 92% with, BM40, BM42 and BM43,
respectively. DCF has a high affinity to the membranes BM32 and BM34. The
extraction percentages for DCF are 82%, and 62%, after 3 and 4 hours of
equilibration, respectively.
For SFM and CBZ, a high extractability was recorded for BM42, as 44% and 41%
respectively were taken up within 3h. Table 8.1 shows the results of a comparative
study for extraction processes using the different polymer membranes.
8. Results and discussion – Block copolymer membranes 75
Fig. 8.1: Monomers used for the synthesis of novel block copolymer membrane
compounds [276]
O
N
O
diacetonacrylamid
CH
2
diphenylethylen
CH
2
O
OMe
methylmethacrylate
OH
O
acrylic acid
CH3
CH2
OOH
O
hydroxyethylmethacrylate
BM43
:
DPE+ HEMA+ MMA
BM34:
DPE + HEMA +AAC
+DAA
BM40:
AAC+ DAA+ DPE
BM42:
DPE + HEMA
BM32:
AAC + DPE
DAA
AAC
DPE
MMA HEMA
H
8. Results and discussion – Block copolymer membranes 76
Table 8.1: Optimum extraction yields for drugs obtained by polymer membranes in
water (V
E
: 10 mL,
β
o
: 1.00 mg/L,
W
F
:
0.500± 0.002 g, n= 3)
Drugs
BM32
%E
BM34
%E
BM40
%E
BM42
%E
BM43
%E
SFM
42 20 13 44 37
CBZ
40 21 34 44 41
DCF
62 75 32 78 89
IBU
57 68 80 88 93
The data in table 8.1 and figure 8.2 clearly reveal that IBU, DCF, CBZ and SFM by
BM42 and BM43 are most effectivly extracted by these polymer membranes
compared to the others. The polymer membrane BM43 is suitable for all of the target
drugs except SFM. The best extractability of SFM within 3 h, 44%, was recorded by
BM42, as shown in figure 8.3 and in table 8.1.
Table 8.2: Extraction data at optimum conditions for polymer membranes in
water (V
E
: 10 mL,
β
o
: 1.00 mg/L,
W
F
: 0.500± 0.002 g, n= 3)
Target
drugs
Eq.
Time, h
Total mass
[µg]
β
s
,
[mg/L]
Total
mass
remaining
[µg]
%E
Type of
polymer
IBU
4 100 0.07 7 93 43
DCF
3 100 0.11 11 89 43
CBZ
3 100 0.59 59 41 43
SFM
3 100 0.56 56 44 42
The overall order of extractability by means of BM42 and BM43 is IBU ≥ DCF >> CBZ
≈ SFM. Obviously the carbonic acid -type drugs IBU and DCF show the relative
highest affinity to both membranes compared to the drugs SFM and CBZ, which form
hydrogen bonds between amino groups and the membrane, assuming a central
cavity of the oxygen -rich helical structure.
8. Results and discussion – Block copolymer membranes 77
Fig. 8.2: Extraction of drugs by polymer membranes as a function of time
a) BM32, b)BM34, c) BM40, d) BM42, e) BM43 (conditions see table 8.1)
0
20
40
60
80
100
02468
%E
Time, h
BM32 polymer
SFM
CBZ
DCF
IBU
0
20
40
60
80
100
02468
%E
Time, h
BM 34 polymer
SFM
CBZ
DCF
IBU
0
20
40
60
80
100
0 2 4 6 8
%E
Time, h
BM40 polymer
SFM
CBZ
DCF
IBU
0
20
40
60
80
100
02468
%E
Time, h
BM42 polymer
SFM
CBZ
DCF
IBU
0
20
40
60
80
100
02468
%E
Time,h
BM43 polymer
SFM
CBZ
DCF
IBU
a)
b)
c)
d)
e)
8. Results and discussion –
Block copolymer membranes
Fig. 8.3:
Comparison of the extractability of active drugs by BM42 and BM43
(for extraction conditions see table 8.2)
8.2 Extraction of tetracyclines drugs by novel polymer membranes
A batch equilibrati
on method was used to measure the sorption of TCs in water
containing 2.0 mg/L of TC, CTC and iso
solutions was shaken together with membrane samples for 10 hours. A 20µL aliquot
of the supernatant
solution was assayed b
applied method (V) see section 11.8. The values of %E were calculated by
equation 7 (see in section 7.3.3).
The experimental results are summarized in table 8.3. The relationship between the
extraction profi
le of each target drug and the extraction times for the different polymer
membranes is presented by fig. 8.4. It can be seen that TC has a perfect ability to be
extracted by membranes BM40, BM42 and BM43. Both pharmaceutical compounds
under investigation (
CTC and iso
significant amounts (%E = 60% and 59%, respectively). A more detailed evaluation of
sorption data is presented in figure 8.4.
The extraction of CTC and iso
equilibrium after 4h (table 8.3). The following orders describe the affinity of the
individual membranes towards tetracyclines:
For TC: BM43 > BM42 >> BM40
For CTC: BM32 > BM42 ≈
BM34 >> BM40.
For iso-
CTC: BM34 > BM32 > BM42
0%
20%
40%
60%
80%
100%
%E
Block copolymer membranes
Comparison of the extractability of active drugs by BM42 and BM43
(for extraction conditions see table 8.2)
8.2 Extraction of tetracyclines drugs by novel polymer membranes
on method was used to measure the sorption of TCs in water
containing 2.0 mg/L of TC, CTC and iso
-
CTC. Each of the different aqueous
solutions was shaken together with membrane samples for 10 hours. A 20µL aliquot
solution was assayed b
y HPLC-
UV. For more details of the
applied method (V) see section 11.8. The values of %E were calculated by
equation 7 (see in section 7.3.3).
The experimental results are summarized in table 8.3. The relationship between the
le of each target drug and the extraction times for the different polymer
membranes is presented by fig. 8.4. It can be seen that TC has a perfect ability to be
extracted by membranes BM40, BM42 and BM43. Both pharmaceutical compounds
CTC and iso
-
CTC) are extractable by BM32 and BM34 in
significant amounts (%E = 60% and 59%, respectively). A more detailed evaluation of
sorption data is presented in figure 8.4.
The extraction of CTC and iso
-
CTC by contacting the polymers, obviously reac
equilibrium after 4h (table 8.3). The following orders describe the affinity of the
individual membranes towards tetracyclines:
For TC: BM43 > BM42 >> BM40
≈ BM32 > BM34.
BM34 >> BM40.
CTC: BM34 > BM32 > BM42
≈ BM40> BM43.
IBU DCF CBZ SFM
78
Comparison of the extractability of active drugs by BM42 and BM43
8.2 Extraction of tetracyclines drugs by novel polymer membranes
on method was used to measure the sorption of TCs in water
CTC. Each of the different aqueous
solutions was shaken together with membrane samples for 10 hours. A 20µL aliquot
UV. For more details of the
applied method (V) see section 11.8. The values of %E were calculated by
The experimental results are summarized in table 8.3. The relationship between the
le of each target drug and the extraction times for the different polymer
membranes is presented by fig. 8.4. It can be seen that TC has a perfect ability to be
extracted by membranes BM40, BM42 and BM43. Both pharmaceutical compounds
CTC) are extractable by BM32 and BM34 in
significant amounts (%E = 60% and 59%, respectively). A more detailed evaluation of
CTC by contacting the polymers, obviously reac
hed
equilibrium after 4h (table 8.3). The following orders describe the affinity of the
BM42
BM43
8. Results and discussion – Block copolymer membranes 79
Table 8.3: Extraction percentage of target drugs from water by polymer membranes
(BM), as a function of time (V
E
: 10 mL, W
F
: 0.500±0.002 g, β
o
: 2.0 mg/L, n= 3)
Table 8.4 summarises the calculated amounts of drugs that remained and which
were absorbed by polymeric membranes. The maximum total mass adsorbed was
found to be198 µg by BM43. The initial amount of TC was 200 µg, so that 98% were
extracted.
It is to note, that the formation of hydrogen bonds between the protonated amino
groups of selected TCs and the oxygen atoms of block copolymer membranes seems
to be responsible for the efficient extraction. (see scheme 7.2, table 2.1, equations 4
and 5 for the structure of selected compounds and PUF).
Table 8.4: Total masses of target drugs determined in extraction processes by
polymer membranes, (V
E
: 10 mL, W
F
: 0.500±0.002 g, t
E
: 4 h, n= 3)
Target
drugs
β
o
, [mg/L]
Total
mass
[µg]
β
s
, [mg/L]
Total
mass
remaining
[µg]
Total
mass
adsorbed
[µg]
%E
BM
TC
2.00 200 0.02 2 198 98 43
CTC
2.00 200 0.85 80 120 60 32
iso-CTC
2.00 200 1.17 116 84 59 34
Time, h
BM
1
2
3
4
5
7
TC
32 40 49 51 55 54 53
34 42 45 46 49 47 47
40 48 53 54 53 53 52
42 38 79 87 97 97 97
43 41 81 97 98 98 98
CTC
32 44 44 47 60 50 50
34 28 34 36 44 42 42
40 17 18 20 20 19 19
42 17 32 45 46 47 46
43 12 14 15 19 18 18
iso-CTC
32 29 35 39 41 42 42
34 36 47 49 59 58 58
40 18 22 28 28 28 27
42 16 18 29 30 30 29
43 14 17 18 20 19 19
8. Results and discussion – Block copolymer membranes 80
Fig. 8.4: Extractability of TCs by polymer membranes as a function of time
a) BM32, b) BM34, c) BM40, d) BM42 and e) BM43 (for extractions
conditions see table 8.3)
0
20
40
60
80
02468
%E
Time, h
BM32
TC
CTC
iso-
CTC
0
20
40
60
80
0 2 4 6 8
%E
Time, h
BM34
TC
CTC
iso-
CTC
0
20
40
60
80
0 2 4 6 8
%E
Time, h
BM40
TC
CTC
iso-
CTC
0
20
40
60
80
100
02468
%E
Time, h
BM42
TC
CTC
iso-
CTC
0
20
40
60
80
100
0 2 4 6 8
%E
Time, h
BM43
TC
CTC
iso-
CTC
b)
c)
d)
e)
a)
8. Results and discussion – Block copolymer membranes 81
8.3 Effect of pH on the sorption by polymeric membranes
8.3.1 Active drugs SFM, CBZ, DCF and IBU
The extraction of target compounds by BM42 and BM43 was tested in diluted
hydrochloric acid media at pH ≈ 3 as described in section 11.5.1. The results of these
batch experiments are given in table 8.5 and figure 8.5. Comparison of these results
with the uptake of drugs from water, as shown in table 8.1, denotes the strong
dependency of the sorption process on the pH value. For example, the compounds
percentage of extractions for SFM, CBZ, DCF and IBU with BM42 in water were
44%, 44%, 78% and 88% respectively, and these extraction percentages increased
in acidic media up to 91%, 84%, 97% and 99% for IBU, as can be clearly seen in
figure 8.6. Figure 8.5 demonstrates the superior extraction efficiency of BM42
compared to BM43.
Table 8.5: Optimum extraction values of drugs obtained by BM42 and BM43
(V
E
: 10 mL, W
F
: 0.05±0.02 g, β
o
: 1.0 mg/L, pH3, t
E
: 3 h, 4 h, n = 3)
polymer
membrane
BM42
BM43
Target drugs
SFM
CBZ
DCF
IBU
SFM
CBZ
DCF
IBU
β
s
[mg/L]
0.09 0.16 0.03 0.16 0.26 0.16 0.03 0.01
%E
91 84 97 99 74 71 97 99
Fig. 8.5: Extraction of active drugs at pH 3 by polymers as a function of time
a) BM42, b) BM43 (for extraction conditions see table 8.5)
0
20
40
60
80
100
120
0123456
%E
Time, h
BM42
SFM
CBZ
DCF
IBU
0
20
40
60
80
100
120
0123456
%E
Time, h
BM43
SFM
CBZ
DCF
IBU
b)
a)
8. Results and discussion – Block copolymer membranes 82
The results reveal the extraction process to be quantitative (99%) for IBU by using
both BM42 and BM43, whereas the extraction yields are lower for SFM and CBZ.
However, SFM and CBZ are more efficiently extracted by BM42 (91% and 84%) than
BM43 (74%, 71%). The order of extractability, IBU ≥ DCF > SFM ≥ CBZ, follows the
order of acidity of these active drugs. (pKa: DCF, IBU ≈ 4, SFM ≈ 6, CBZ ≈ 14; see
table 2.2).
Figure 8.6: Influence of pH on the extraction of drugs by polymer membranes
(for extraction conditions see tables 8.1 and 8.5)
The presented data in fig. 8.6 show a slight influence of pH on the sorption profile. It
can be concluded, that optimum sorption properties are provided by membrane
BM42.
8.3.2 Influence of pH on the sorption of TCs
To improve the extraction properties of the TCs under investigation a batch
experiment, described in section 7.5.4.1, was performed by means of the BM42 and
BM43 polymer membranes BM34, in acidic aqueous solution at pH ≈ 3. An initial
concentration of 1.0 mg/L was used throughout.
0
20
40
60
80
100
%E
SFM CBZ DCF IBU
Target drugs
BM42 polymer membrane
pH 3
water
0
20
40
60
80
100
%E
SFM CBZ DCF IBU
Target drugs
BM43 polymer membrane
pH 3
water
8. Results and discussion – Block copolymer membranes 83
Table 8.6: Optimum extraction values of TCs obtained (V
E
: 10 mL, W
F
: 0.05±0.02,
β
o
: 1.0 mg/L, pH 3, t
E
: 4 h, n = 3)
Target drugs
β
s
(mg/L)
%E
BM34
TC
0.30 99
CTC
0.29 71
iso-CTC
0.66 44
BM42
TC
0.32 68
CTC
0.27 73
iso-CTC
0.61 39
BM43
TC
0.61 99
CTC
0.27 73
iso-CTC
0.50 50
The data in table 8.6 and figure 8.7 is to conclude that after 4 h of shaking, a good
extraction percentage for all of the TC drugs employed was achieved by BM43.
The order of extraction yield is: TC > CTC > iso-CTC, thus correlating with the
decrease of polarity of these compounds; see table 2.2.
By comparing the results in table 8.6 with the results of extraction of TCs in water
media by BM43 (table 8.3), it can be concluded that the best extraction is achieved in
acidic media. Figure 8.7 and 8.8 show clearly that the sorption of TC drugs depends
on the pH value of the extraction solution. The highest rate of extrraction was by
BM43 in acidic solution. The extraction percentages reach 99%, 73%, and 50%,
while the %E recorded by BM43 in water was 98%, 19%, and 20% for TC, CTC and
iso-CTC, respectively.
The table 8.7 reports the total mass which remain of tetracyclines in solution and
were adsorbed by the BM43 polymer membrane in acidic media.
8. Results and discussion – Block copolymer membranes 84
Fig. 8.7: Extraction of TCs drugs at pH 3 by polymer membranes
a) BM34, b) BM42, c) BM43 (for conditions of extraction see table 8.4)
0
20
40
60
80
100
02468
%E
Time, h
BM34 polymer membrane
TC
CTC
iso-CTC
0
20
40
60
80
0 2 4 6 8
%E
Time, h
BM42 polymer membrane
TC
CTC
iso-CTC
0
20
40
60
80
100
0 2 4 6 8
%E
Time, h
BM43 polymer membrane
TC
CTC
iso-CTC
c)
a)
b)
8. Results and discussion – Block copolymer membranes 85
Fig. 8.8: Influence of pH on extraction of TCs by BM43 (for conditions of extractions
see tables 8.1 and 8.4)
Table 8.7: Data of extraction of TCs by membrane BM43
(VE: 10 mL, W
F
: 0.05±0.02, β
o
: 1.0 mg/L, pH 3, t
E
: 4 h, n = 3)
compounds
β
o
[mg/L]
Total mass
[µg]
β
s
[mg/L]
Total mass
remaining [µg]
Total mass
adsorbed [µg]
%E
TC
1.0 100 0.10 1 99 99
CTC
1.0 100 0.27 27 73 73
iso-CTC
1.0 100 0.50 50 50 50
8.4 Recovery of TCs drugs from loaded BM34 and BM43 polymers
8.4.1 Extraction from acidic media
The same extraction procedure as described in section 11.6.1 has been applied to
extract 2.0 mg/L of each of the drugs TC, SFM, CBZ, and IBU in 10 mL acidic
aqueous solution (pH 3) by 0.50 g of BM34 or BM43. These mixtures were
mechanically shaken until sorption equilibrium was reached (4 h). The analytes,
which remained in the aqueous solutions, were determined by the HPLC-UV
technique according to method VI, as shown in section 11.8. The total masses of
drugs are given in table 8.8 and figure 8.9.
0
20
40
60
80
100
%E
TC CTC iso-CTC
Drugs
BM43 polymer membrane
pH 3
water
8. Results and discussion – Block copolymer membranes 86
Table 8.8: Total masses of target drugs determined by extraction processes with
polymers (β
o
: 2.0 mg/L, t
E
: 4 h, V
E
: 10 mL by 0.50 g of polymer foam, pH 3,
dilute HCl, n = 3)
Target
drugs
β
o
[mg/L]
Total
mass
[µg]
β
s
[mg/L]
Total
mass
remaining
[µg]
Total
mass
adsorbed
[µg]
%E
BM34 polymeric membrane
TC
2 20 0.40 4 16 80
SFM
2 20 0.45 4.5 13.9 70
CBZ
2 20 0.72 7.2 12.8 64
IBU
2 20 0.07 0.7 19.6 98
BM43 polymeric membrane
TC
2 20 0.23 2.3 17.7 89
SFM
2 20 0.76 7.6 12.4 62
CBZ
2 20 0.61 6.1 13.9 70
IBU
2 20 0.07 0.7 19.3 97
From the results obtained by each polymeric membrane, as demonstrated in fig. 8.9,
it may be observed that IBU is completely extracted by both BM34 and BM43
polymeric membranes. In general, the order of extraction is: IBU>>TC ≥ SFM ≥ CBZ
for BM34, and IBU > TC > CBZ ≥ SFM for BM43, which corresponds to the sequence
of extraction, illustrated in figure 8.8.
8. Results and discussion – Block copolymer membranes 87
Fig.8.9: Extraction of target active drugs at pH 3 by selected polymer membranes
a) by BM43, b) by BM34 (see conditions in table 8.4)
8.4.2 Recovery of drugs loaded on BM34 and BM43 polymers
The drug loaded polymer cubes used in each batch were separated and washed with
10 mL of bidistilled water. The water was collected and analysed to control the
washing step.
Acetone and acetonitrile were employed to elute the analytes. The chromatography
method (VII) was used to determine the recovery as described in section 11.8. The
recovery results listed for both BM34 and BM43 polymeric membranes in tables 8.9
0
20
40
60
80
100
120
0 1 2 3 4 5
%E
Time, h
BM43 polymer membrane
TC
SFM
CBZ
IBU
0
20
40
60
80
100
120
012345
%E
Time, h
BM 34 polymer membrane
TC
SFM
CBZ
IBU
b)
a)
8. Results and discussion – Block copolymer membranes 88
and 8.10 illustrate the recovery profile of all elutions for both the BM34 and BM43
polymeric membranes.
Table 8.9: Amounts of target drugs eluted from loaded BM34 and BM43 cubes
by acetone and acetonitrile, (W
F
: 0.5 g, t
E
: 4 h, t
R
: 1 h, V
R
: 10 mL and n = 3)
Target
drugs
Loaded
amount
100%
µg
BM34
Total amount eluted (µg)
Acetone
Acetonitrile
Acetone
Acetonitrile
BM34 polymeric membrane
TC
16.7 0.81 1.02 8.10 10.20
SFM
15.6 0.32 0.56 3.20 5.60
CBZ
16.1 0.69 0.62 6.90 6.20
IBU
19.3 1.13 0.63 11.30 6.30
BM43 polymeric membrane
TC
17.7 1.21 0.86 12.10 8.60
SFM
12.4 0.32 0.34 3.20 3.40
CBZ
13.9 0.71 0.45 7.10 4.50
IBU
19.3 1.21 0.65 12.10 6.50
Table 8.10: Maximum recovery percentage of target drugs with BM34 and
BM43 cubes by acetone and acetonitrile as eluents (t
R
: 1 h, V
R
: 10 mL)
In addition, the influence of time on the elution processes is shown in figs. 8.10 and
8.11. It can be concluded, that the equilibrium process time is already reached after 2
h. The elution efficiency of acetone is remarkably higher compared to acetonitrile.
Target drugs, BM34
TC
SFM
CBZ
IBU
Acetone
81% 32% 69% 100%
Acetonitrile
100% 57% 62% 63%
Target drugs, BM43
TC
SFM
CBZ
IBU
Acetone
100% 32% 71% 100%
Acetonitrile
86% 34% 43% 65%
8. Results and discussion – Block copolymer membranes 89
Fig. 8.10: Recovery of drugs from loaded BM34 with a) acetone, b) acetonitrile as
function of time (t
R
:1 h, V
R
: 10 mL, n=3)
Fig. 8.11: Recovery of drugs from loaded BM43 as a function with a) acetone,
b) acetonitrile (W
F
: 0.5 g, t
E
: 4 h, t
R
: 1 h t
R
: 1h, V
R
: 10 mL, n = 3)
Obviously, in the case of BM43 the recovery of IBU and tetracycline is sufficient
(~ 80 – 100 %), whereas SFM and CBZ were eluted in lower yields. The elution
pattern found for the BM34 polymer shows similarities to BM43. However, optimum
properties for both extraction and elution are offered by BM43, particularly for the
case of TC and IBU.
0
20
40
60
80
100
120
0 20 40 60 80 100 120 140
Recovery(%)
Time, min
Acetone
TC
SFM
CBZ
IBU
0
20
40
60
80
100
120
0 20 40 60 80 100 120 140
Recovery (%)
Time, min
Acetonitrile
TC
SFM
CBZ
IBU
a) b)
0
20
40
60
80
100
120
0 20 40 60 80 100 120 140
Recovery (%)
Time, min
Acetone
TC
SFM
CBZ
IBU
0
20
40
60
80
100
0 20 40 60 80 100 120 140
Recovery (%)
Time, min
Acetonitrile
TC
SFM
CBZ
IBU
b)
a)
8. Results and discussion –
Block copolymer membranes
Fig. 8.12:
Comparison of recovery processes a) MB34 and b) BM4
membranes with different eluting agents (t
The experimental results shown in fig. 8.12 demonstrate that acetone is the suitable
organic solvent to elute drugs from both polymer membranes BM34 and BM 43 for all
of the
target drugs except for SFM. It has the same recovery yield (27%) of BM43 for
both eluting solvents. However, when BM34 was loaded in the case, the recovery
yield of SFM achieved in acetonitrile (57%) is greater than in acetone (32%).
0
20
40
60
80
100
TC
0
20
40
60
80
100
TC
a)
b)
%R
%R
Block copolymer membranes
Comparison of recovery processes a) MB34 and b) BM4
3 polymeric
membranes with different eluting agents (t
R
: 1h, V
R
: 10 mL, n = 3)
The experimental results shown in fig. 8.12 demonstrate that acetone is the suitable
organic solvent to elute drugs from both polymer membranes BM34 and BM 43 for all
target drugs except for SFM. It has the same recovery yield (27%) of BM43 for
both eluting solvents. However, when BM34 was loaded in the case, the recovery
yield of SFM achieved in acetonitrile (57%) is greater than in acetone (32%).
SFM CBZ IBU
Acetone
Acetonitrile
SFM CBZ IBU
Acetone
Acetonitrile
BM43
BM34
90
3 polymeric
: 10 mL, n = 3)
The experimental results shown in fig. 8.12 demonstrate that acetone is the suitable
organic solvent to elute drugs from both polymer membranes BM34 and BM 43 for all
target drugs except for SFM. It has the same recovery yield (27%) of BM43 for
both eluting solvents. However, when BM34 was loaded in the case, the recovery
yield of SFM achieved in acetonitrile (57%) is greater than in acetone (32%).
Acetone
Acetonitrile
Acetone
Acetonitrile
8. Results and discussion – Block copolymer membranes 91
Conclusion
In order to carry out experiments, dissolveddrugs were put in contact with cubes of
novel block copolymer membranes (BM32, BM34, BM40, BM42 and BM43) which
were synthesized in the University of Paderborn. The extracted and re-extracted
amounts were determined by HPLC-UV, as shown in section 11.8.2. Certain open-
cell-membrane compositions were tested in batch models. Different factors were
studied to find the best extraction conditions for the selected drugs and metabolites:
pH 3, adjusted by using 0.1 mol/L HCl
Optimum time of extraction: 4 hours
This condition recovered 89 % of TC with polymer BM43, 98 % of IBU by with
polymer BM34, 70 % of CBZ with BM43 and 70 % of SFM by BM34, from solutions at
a concentration of 2 mg/L.
Different factors have been studied to find the best recovery conditions for these
drugs from loaded block copolymer membrane:
Acetone as eluting agent
Time of recovery: 1h
This condition gave recovery yields of 100 % for both TC and IBU, 71 % for CBZ and
32 % for SFM.
The results obtained show that some of the novel polymers, inparticular BM34 and
BM43, demonstrate excellent sorption and desorption properties towards TC and
IBU.
These open-cell membrane systems offer in some cases advantageous properties
compared to the PUF-foams investigated (see chapter 7).
9. Results and discussion – comparative discussion 92
9. Result and discussion comparative discussion
9.1
Comparative study between the extraction and elution behaviour of
PUF and BM
The results of the extraction of active drugs and metabolites by means of PUF and
selected novel membranes were compared by the data in table 9.1.
Table 9.1: Comparison of the extractability of drugs by PUF and polymeric
. membranes (V
E
: 100 mL, β
o
: 3 mg/L, W
F
:0.500±0.002 g, 1 cm
3
, n = 3)
Compounds
%E
PUF (A-type)
BM42
BM43
SFM
98 91 -
CBZ
94 84 -
TC
56 - 99
CTC
64 73 -
iso-CTC
60 - 50
The polarity and the acid-base properties of analytes as well as the hydrophilic and
hydrophobic membrane characteristics influence the extractability of analytes by both
PUF and polymeric membranes.
The active drugs, SFM, CBZ, TC and CTC were extracted by using both
polyurethane foam and polymeric membranes. The maximum extraction yields of the
pharmaceuticals were 98% (SFM), 94% (CBZ), and 60% (iso-CTC) by PUF. While
the highest extraction was 99% for TC and 73% for CTC by BM43 and BM42
respectively as shown in table 9.1. The best extraction of SFM and CBZ was
obtained by using PUF in acidic solution, whereas for TC and CTC the highest
extraction efficiency was achieved by the polymeric membrane BM43, also in acidic
solution. For the metabolite iso-CTC, the best extraction efficiency was achieved with
PUF membrane under the same conditions, (60%) as illustrated in figure and table
9.1. It is striking that the extractability of TC is characterized by broad limits of
variation (fig. 9.1), compared to the other investigated compounds and extraction
system.
The rates of recoveries can be compared between all types of extracting polymers in
the cases of SFM and CBZ. Evidently, the extraction of these compound is nearly
9. Results and discussion –
comparative discussion
completely under certain conditions by means of PUF (table 9.2), whereas the
extraction yields are significant lower (
rates of recovery are higher for PUF than for the novel polymers. These membrane
types reveale excellent properties for IBU (%E = 98, %R = 100) by BM34 and TC
(%E = 89, %R = 100) by BM43.
Fig.9.1:
Comparison of extractability of se
(all drugs by BM42 except TC and iso
Table 9.2:
Comparison of recoveries obtained with PUF and polymeric membranes,
(V
R
: 30 mL, V
E
: 100 mL, t
1.0 mg/L,
W
F
:
0.500± 0.002 g, n= 3) t
block copolymers, recovery in acetone as elueut
Drugs
SFM
CBZ
These findings demons
trate that both active drugs SFM and CBZ have good results
for extraction from aqueous solution by using PUF membrane at these conditions
(see table 9.2).
0
20
40
60
80
100
SFM
%E
comparative discussion
completely under certain conditions by means of PUF (table 9.2), whereas the
extraction yields are significant lower (
~ 60 - 70 %) with BM34 an
d BM43. Also, the
rates of recovery are higher for PUF than for the novel polymers. These membrane
types reveale excellent properties for IBU (%E = 98, %R = 100) by BM34 and TC
(%E = 89, %R = 100) by BM43.
Comparison of extractability of se
lected drugs by PUF and BM membranes
(all drugs by BM42 except TC and iso
-
CTC by BM42, for conditions see table 7.21)
Comparison of recoveries obtained with PUF and polymeric membranes,
: 100 mL, t
E
: 3 h, t
R
: 1 h, n = 3, for PUF), ((V
0.500± 0.002 g, n= 3) t
R
: 1 h, V
R
: 10
mL, n = 3, for novel
block copolymers, recovery in acetone as elueut
)
PUF (A-type)
polymers
%E
%R
BM34
BM43
%E
%R
%E
%R
98 59 70 48 62
40
94 60 64 53 70
46
trate that both active drugs SFM and CBZ have good results
for extraction from aqueous solution by using PUF membrane at these conditions
SFM
CBZ TC CTC iso-CTC
selected compounds
PUF
BM
93
completely under certain conditions by means of PUF (table 9.2), whereas the
d BM43. Also, the
rates of recovery are higher for PUF than for the novel polymers. These membrane
types reveale excellent properties for IBU (%E = 98, %R = 100) by BM34 and TC
lected drugs by PUF and BM membranes
CTC by BM42, for conditions see table 7.21)
Comparison of recoveries obtained with PUF and polymeric membranes,
: 1 h, n = 3, for PUF), ((V
E
: 10 mL,
β
o
:
mL, n = 3, for novel
BM43
%R
40
46
trate that both active drugs SFM and CBZ have good results
for extraction from aqueous solution by using PUF membrane at these conditions
PUF
BM
9. Results and discussion – comparative discussion 94
Fig.9.2: Comparison between BM34 and BM43 polymer membranes ((V
E
: 10 mL,
β
o
: 2.0 mg/L,
t
E
: 3 h, W
F
:
0.500± 0.002 g, n= 3) t
R
: 1 h, V
R
: 10 mL, n = 3,
recovery in acetone as elution)
Obviously, as shown in figure 9.2, both the extraction and recovery processes of IBU
and TC are sufficient. BM34 is a suitable membrane for all of the drugs, i.e. the drugs
have high yields of extractions and recovery as well with BM34, except for the
extraction of CBZ and TC under these conditions.
9.2 Comparative study of extraction by polymer membranes and other
techniques
Compared to traditional methods such as liquid–liquid extraction (LLE) [216] and
solid -phase extraction (SPE) [297], which are based on extraction procedures to
remove the pharmaceuticals compounds from water, PUF and the novel block
copolymer membranes offer further advantages due to the method's simplicity,
occupational safety and negligible contamination of the environment.
Solvent consumption
In this technique the polymeric extraction membranes (PEM) have a low
consumption of organic solvent (10 ml of organic solvent is required to eluate
the analytes from polymer membranes) compared to LLE, which used a large
volume, some times more than 100 mL of organic solvent and SPE in some
0
20
40
60
80
100
%E %R %E %R %E %R %E %R
SFM CB Z IBU TC
BM34
BM43
9. Results and discussion – comparative discussion 95
cases it is required more than 15 ml [40]; and as a result, the new process is
more environmentally friendly.
Extraction time
The extraction time for LLE is more than 4 and up to 12 hours, and for SPE
may be in some cases it is more than 6 hours, while the extraction time for
PEM is 3 hours with case PUF and 4 hours with block copolymer membranes.
Clean up
In principal the PEM technique offers a low –cost, simple and in some certain
cases a relatively more efficient clean up than the LLE and SPE methods [216,
217].
10. Summary 96
10. Summary
Recent studies indicate the ubiquitous and widespread occurrence of low- level
concentrations of pharmaceuticals, and their metabolites via human and veterinary
urinary, and/or faecal excretion. Also waste disposal of expired pharmaceutical and
pharmaceutical manufacturing reach to the aquatic environment. As a consequence,
a wide variety of pharmaceuticals, organic compounds, and other wastewater-
related contaminants are frequently detected in streams that receive agricultural,
domestic, and/or industrial wastewater effluent. Some of these substances have the
potential to enter potable supplies.
Furthermore, recent studies performed in Europa and other countries demonstrated
the occurrence of a variety of pharmaceutical compounds in raw sewage. It means
that these compounds are not totally eliminated in the wastewater treatment plants.
Hence, it is an urgent need to improve the techniques of purification of water,
wastewater and to employ sensitive analytical methods in order to monitore the input
of drugs and their metabolites into the aquatic environment. The analytical
techniques usually used such as HPLC-UV, still afford an efficient sample
pretreatment to enrich and separate the analytes from the complex matrix.
The aim of the study was to investigate the applicability of certain types of open cell
solid membranes to extract efficiently selected drugs of environmental concern such
as sulfamethoxazole (SFM), carbamazepine (CBZ), diclofenac (DCF), ibuprofen
(IBU), tetracycline (TC) and chlortetracycline (CTC). These active drugs were
selected due to their high quantities applied in human and veterinary medicine and
their relative high concentrations found in the aquatic environment in previous
studies.
The metabolites investigated in this study were isochlortetracyclines (iso-CTC) and
N-4-acetylsulfamethoxazole (ASFM). The iso-CTC is commercially available,
whereas ASFM was synthesized and the structure confirmed by common
spectroscopic methods.
To carry out the membrane studies, Polyurethane foams (PUF) and novel block
copolymer membranes (BM) were used.
10. Summary 97
In the first part of the present work, four types of polyurethane foams (a, b, c and d)
were examined by batch experiments to extract amounts of metabolites ASFM from
water. Three of these polyether-based PUF membranes, a, b, c, have different pores
size of (100 µm, 50 µm and 10 µm resp.). Type d is a polyester-based PUF (pore
size 10 µm). In case of the extractability of metabolite ASFM by these membranes
the following order was found: a > b ≥ c. The extraction percentages recorded were
48%, 34%, and 33% respectively, i.e., the membrane a with the largest pores, has
the highest extraction efficiency. An extraction yield of 33% ASFM was achieved with
PUF-polyether type c and 30% with PUF-polyester type d. it is assumed, that the
PUF-polyether extracts comparatively more strongly than PUF-polyester due to
easier formation of hydrogen bonds with the amino groups in ASFM molecules. A
central cavity of the oxygen rich helix structure of the polyether-type can be made
responsible for the extraction behaviour observed.
To improve the capability of PUF-polyether, different factors affecting the separation
processes were studied, such as the effect of pH, shaking time and interfering ions
(effect of salts) on the extraction of CBZ, SFM and its main metabolite ASFM. It can
be concluded that the drug permeability through the membrane strongly depend on
the composition of the aqueous medium. The ability of sorption generally increased in
the order pH3 > pH 9 >> pH 7. The achieved extraction percentages in acidic media
(pH 3) are 79%, 80% and 73% for CBZ, SFM and for ASFM. These results increase
to 94% for CBZ and 98% for both SFM and its metabolite ASFM in 0.1M of NaCl. The
effect of individual cations on the sorbability of drugs increases in thefollowing order:
Na
+
≈ NH
4+
> K
+
> Mg
2+
.
Recovery experiments of CBZ, SFM and ASFM by means of organic solvents,
acetone and acetonitrile, were carried out. The maximum recovery yields for CBZ
(52%)SFM (59%) and ASFM (60%), were obtained by using acetone as eluent.
In addition several factors affecting the extraction efficiency of the target drugs TC,
CTC and its metabolite iso-CTC were studied. From the obtained results, it can be
concluded that the most effective conditions for batch experiments are: 100 mL of
extraction volume, 3 mg/L of each target compound, 0.500±0.002 g of dry foam
(1 cm
3
) and equilibrium time 3 hours. The extraction efficiency of CTC, iso-CTC and
TC achieved in acidic media of pH 3 were 64%, 60% and 56% respectively.
10. Summary 98
In the second part, a novel type of block copolymer compounds (created at the
University of Paderborn, Chemical Engineering) was investigated. These membranes
denoted as BM40, BM42, BM43, BM32, BM34 were applied as open cell solid
membranes to extract each of active target drugs IBU, DCF, CBZ, SFM, and TC.
Maximum extraction efficiencies were achieved with BM42 (43% SFM, 44% CBZ). By
BM43 89% DCF, 93% IBUand 98% TC were separated from solutions containing 1
mg/L of the individual compounds. By means of BM32 and BM34 CTC (60%) and
iso-CTC (59%) were extracted, too.
Several factors were varied in batch experiments in order to improve the yields and
efficiencies of drug extraction from aqueous solution by the block copolymer
membranes. The main factor which was studied for this purpose was the effect of pH
media on active drugs. The maximum extraction efficiencies of all selected
compounds were found in acidic media at pH 3 by use of BM43 membrane. After 4
hours of equilibrium time 99% of TC were extracted, 73% of CTC, 50% of iso-CTC,
62% fof SFM, 70% of CBZ, 97% of IBU. BM34 also showed good results, since the
extraction percentage for both active target drugs TC and IBU exceed 97%.
The recoveries of drugs from cubes of BM34 and BM43 loaded with TC, SFM, CBZ
and IBU was investigated. For this purpose, acetone and acetonitrile were used as
eluents. By acetone, 100% of IBU, 81% of TC, 69% of CBZ and 32% of SFM were
recovered from BM34, whereas acetonitrile eluted completely TC and the other drugs
in the range between 57 and 63%. In the case of BM43 acetone eluted TC and IBU
quantitatively, however, SFM and CBZ to a less extent (~ 60%). The recovery of the
loaded drugs was not so efficiently in the case of acetonitrile. The yields range from
34% (SFM) to 86% (TC).
More work is required to understand more completely the processes of extraction and
transport of drgs across the different types of soild membranes. Anyway, the different
types of polymeric membranes, polyurethane foams and the novel block copolymers
investigated in this work reveal different profiles of extraction and elution behaviour.
Due to their distinct selectivities towards various classes of active drugs and
metabolites, they offer some potential for certain applications.
Such types of membranes may become important in future in the fields of water
treatment and analytical chemistry as well. Especially in miniaturized analytical
systems used for sample pretreatment, new materials may offer some advantages.
11. Experimental 99
11 Experimental
11.1 Synthesis of ASFM:
SFM was reacted with acetylchloride in pyridine as described in Scheme 11.1. To
a stirred solution of sulfamethoxazole (0.1 mole) in pyridine (300 mL) was added
dropwise acetylchlorid (0.1 mole) at 0-5
o
C. The reaction mixture was stirred for 8
h at room temperature. Then solution was concentrated by rotary evaporator to
about 40 mL and poured into excessive water. The precipitate formed was
washed with 1 M hydrochloric acid and water respectively and then dried to a
constant weight. Recrystallization from acetonitrile yielded ASFM yield (65 %) as
a pale yellow amorphous solid m.p. 205-210
o
C (Lit. 207
o
C), [277-279].
Scheme 11.1: Synthesis of N-4-acetylsulfamethoxazole
11.2 Development of HPLC-UV methods
The transport of analytes was monitored by HPLC and UV-detection. Aliquots
were taken from the liquid phase at intervals by means of a micro-liter syringe.
The HPLC-UV developed methods for the selected drugs and some of their
metabolites are described in section 11.8 (Method I and II). The stock solutions of
metabolites and the active drugs were prepared by dissolving appropriate
amounts of the drugs in methanol. In order to culculate the external calibration
curves, ten different concentrated solutions were prepared in a concentration
rang of 0.5-10 mg/L. These solutions were prepared by diluting of different
aliquots of appropriate stock solution in double distilled water.
In the membrane tests the concentration of the drugs was 3 mg/L and the pH-
value was adjusted to 9.0. Variations in the pH values (3.0, 7.0 and 9.0) show
some influence on the selected metabolite and drugs (ASFM, SFM and CBZ).
SFM
ASFM
11. Experimental 100
Moreover, pH 3.0 has the best response from the selected compounds. From
these observations it was concluded that, in order to compensate the highest
response, the calibrating standards solutions and the sample should have the
same pH values.
The analytes were introduced into the chromatographic system by an
autosampler connected with UV-Vis Detector. (three repeated measurents, n = 3)
11.3 General procedure
11.3.1 Calibration
in order to prepare different concentrations from the stock solutions, the analyes
were dissolved in methanol. All stock solutions were stored in a refrigerator
(- 4
o
C) to be protected against degradation. They were warmed up to room
temperature before use. All laboratory glassware were soaked in large quantity of
royal water or King's water (3:1(v/v) of HCl: HNO
3
) for 24 hours before use than
washed with double distilled water for three times than dried in an oven (40
o
C).
11.3.2 Pretreatment of membrane
11.3.2.1 PUF membrane
Polyurethane foam is not available in pure form; it usually contains a variety of
reagents and additives.
Considerable care was taken to remove any loosely-held organic and inorganic
substances.
The following ppretreatment steps were carried out:
1. The sheet of polyurethane foam was cut into cubes 1.0 cm
3
with scissors.
2. The foam cubes were soaked in a large quantity of 1M HCl for 24 hours to
remove inorganic contaminating soluble substances.
3. Foam cubes were then made free from acid by repeatedly squeezing and
washing by double distilled water several times until the pH of the rinse water
was unchanged after one hour of soaking.
4. After possible removal of water by the above procedure, the foam cubes
were refluxed with acetone in a Soxhlet extraction apparatus for 6 hours to
remove organic contaminating soluble substances. The wasted acetone was
11. Experimental 101
pale yellow while no change in the colour of the PUF was observed (figure
11.1).
5. The foam was dried in a clean air and finally it was stored in brown glass
jars to be ready for using.
11.3.2.2 Block copolymer membrane (BM)
1. Sheets of the polymers are stored under water. 0.5 cm
3
cubes of each
polymer were cut with scissors.
2. Acetone treatment: The polymer cubes were refluxed with 80 mL of acetone
(b.p. 56°C) for 1 h.
3. Methanol treatment: The polymer cubes were refluxed with 80 mL of
methanol (b.p. 68°C) for 1 h.
4. Washed three times with distilled water and dried in a clean air then the
polymer cubes were kept under double distilled water to be ready for using.
Fig. 11.1: Purification of PUF foam, a) acetone after foams treatment,
b) pure acetone
b)
a)
11. Experimental 102
11.3.3 Blank sample
Blank samples were prepared by the same procedure that was applied on the
polymer and PUF cubes membrane in distilled water.
The blank samples were used to control the membranes for contaminating and to
identify the absorption peaks from membrane. Table 11.1 lists the peaks that
were recorded with the polymer foam in distilled water by applying HPLC-UV
technique, e.g for polymer membranes (Method III and IV). The chromatogram is
given in Figure.11.2.
Table 11.1: Impuirites in the blank samples of polymer membranes detected by
HPLC-UV (1h-treatment in methanol at room temperature)
Size of peak
Retention
time (R
t
)
Polymers Type
big
2.93 BM 34
very small
13.00
big
2.14
2.39
BM 40
very small
4.53
small
5.85
big
2.42 BM 42
big
2.33
2.39
BM 43
small
14.12
Fig. 11.2: HPLC-UV chromatogram: blank sample of BM34
11. Experimental 103
11.4 Extraction procedures
PUF membrane
The influence of extraction time on 3.0 mg/L-solutions of CBZ, SFM and its
metabolite ASFM was investigated. In separate batch experiments,
0.500±0.002 g dry foam (1 cm
3
cubes of four types from PUF) was mixed with
100 mL solution of the target drugs and ASFM.
These solutions were placed in a series of stopper PUF bottles and shaken by a
mechanical shaker 150 r/min for various times intervals for about 6 hours to
ensure sorption equilibrium. The target compound which remained in the
aqueous solutions, were determined
by HPLC-UV technique method II.
11.4.1 Influence of the pH solution on the sorption of the selected drugs .
and some of their metabolites
Within PUF type A, TM23450 (polyether-PUF), the same previous experimental
procedure was employed in various aqueous solutions at pH 3, 7 and 9. These
solutions were prepared by adding drops of 1 M HCl or NaOH. A digital pH meter
was used to adjuste pH. The solutions of the target drugs were shaken together
with PUF cubes over time intervals up to 5 h to ensure equilibrium. The foam
cubes were separated and each amount of target drugs remained in solution was
measured by HPLC-UV method II which is described in section 11.8.
Note: Solutions of TCs were adjusted to pH 3, pH 7 and non- buffered water
instead pH 9 was used.
11.4.2 Influence of cations on the sorption of the selected drugs and
metabolites
Aqueous solutions (100 mL) containing 3.00 mg/L of ASFM, SFM and CBZ were
equilibrated for 3 hours with 0.50± 0.01 g of PUF foam at pH 3, in presence of
0.1M of KCl, NaCl, NH
4
Cl and Mg
2
Cl at equilibrium time (3 hours).
11. Experimental 104
11.5 Extraction procedures
Block copolymer membranes and the target active drug
To investigate the effect of shaking time on the uptake of the compounds on
polymer membrane, the polymer cubes 0.500±0.001g dry (0.5 cm
3
cubes) of five
types of polymer membranes denoted as BM32, BM34, BM40, MB42 and BM43
were equilibrated with 10 mL solution of each selected drug 1.0 mg/L of SFM,
CBZ, DCF and IBU at pH 3 (5 µL of 1 M HCl). These solutions were placed in a
series of stopper polymer bottles and mechanically shaken at 150 r/min over
various time intervals (1, 2, 3, 4, 5 and 6 hours) until sorption equilibrium was
achieved. Then the solutions were neutralized by 5 µL 0.1 M NaOH and analysed
by HPLC-UV technique method III.
Block copolymer membranes with target TC drugs
The same procedure described above was applied to extract each of TC, CTC
and iso-CTC with five types of polymer membranes for 7 hours until equilibrium.
The concentration of these target drugs after neutralisation was measured by
HPLC-UV technique method IV.
11.5.1 Effect of pH on the sorption of selected compounds by block
copolymer membranes
Target active drugs SFM, CBZ, DCF and IBU
In a separate batch experiment, 0.50±0.01 g of dry and clean foam, 0.5 cm
3
cubes of BM42 and BM43 polymer membranes were mixed with 10 mL solution
containing 1.0 mg/L of one of drugs at pH 3 was adjusted by adding 5 µL of 1 M
HCl. These solutions were contained in a series of stopper polymer bottles and
mechanically shaken at 150 r/min for 5 hours until equilibrium. Then the solutions
were neutralized and analyzed by HPLC method III.
Target TCs drugs
Into a dry 10 ml polymer bottle an accurate 0.50±0.06 g of 0.50 cm
3
from each of
BM34, BM42 and BM43 cubes were added 1.0 mg of each analyte (TC, CTC,
11. Experimental 105
iso-CTC). The additions took place at acidic media by using 10 µL of 1 M HCl
(pH ≈ 3). The different aqueous solutions were shaken with a mechanical shaker
for 5h. 20 µL of the residual analyte aliquot were assayed by HPLC-UV
technique after neutralization with 10 µL of 0.1M of NaOH. The method IV was
used as depicted in section 11.8.
11.6 Recovery procedure
11.6.1 PUF membrane
The dried foam cubes (0.500±0.003 g, 1.0 cm
3
) were equilibrated with 100 ml
aqueous solution of each ASFM, SFM and CBZ (5.0 mg/L) in the presence of a
few drops of 1 M of HCl (pH 3) and 0.1 M of NaCl. The solutions were shaken in
separate polyurethane bottles until (1 h). The foam cubes were separated by a
glass frit and washed three times with 10 ml of double distilled water. The
washing water was tested by the HPLC-UV, to detect the presence of any soluble
drugs in the washing water.
Acetone and acetonitrile were utilized to elute each of the compounds from the
loaded PUF cubes. 30 mL of each eluate were placed in a flask with a ground
stopper containing the loaded PUF cubes. The solutions were shaken for various
period of 30, 60 and 120 min by a mechanical shaker at 150 r/min. 500 µL of
each eluate have been taken and these samples were left in open air to
evaporate the solvents. Finally 500 µL of mobile phase were added to dissolve
the dry residue in order to determine the target drugs by the HPLC-UV technique
method II.
11.6.2 Novel block copolymer membranes
In separate experiments, 0.50±0.02 g of dry foam (0.5 cm
3
cubes) were mixed
with 10 mL solution of each drug containing 2.0 mg/L of target drugs (TC, SFM,
CBZ and IBU) at pH3 (1 M HCl). These solutions were contained in a series of
stopper polymer bottles and were shaken by a mechanical shaker at 150r/min
until sorption equilibrium (4 hours) achieved. The polymer cubes were separated
and washed in a glass frit for 3 times with 10 mL of double distilled water. Then
we tested the washing water by HPLC-UV to detect the presence of any soluble
drugs in the washing water.
11. Experimental 106
Acetone and acetonitrile were utilized to elute the analytes for this purpose the
loaded cubes were placed in a flask with a ground stopper. The solutions were
shaken for 2 hours (30, 60, 90, 120 min) by a mechanical shaker at 150 r/min.
The same procedure was applied for PUF. The amount of eluted compounds
from the loaded polymers was determined by HPLC methods and V and VI.
11.7 Materials, equipments and chemicals
The chemicals, materials and equipments which were used in the present work
are listed in tables 11.3, 11.4 and 11.5 respectively.
Table 11.2: Chemicals used in this work
Chemical supplier Chemical supplier
Acetic acid
Fluka
Methanol
Aldrich
Acetylchoride
Aldrich
Nitric acid
Fluka
Buffer solution Titrisol pH 7
Merck
Ibuprofen
Fluka
Buffer solution Titrisol pH 8
Merck
Iso- chlortetracycline
Fluka
Buffer solution Titrisol pH 9
Merck
Potassium chloride
Fluka
Buffer solution Titrisol pH
10
Merck
Potassium
dihydrogenphosphate
Fluka
Carbamazepine
Fluka
Pyridine
Aldrich
Chlortetracycline
Fluka
Sulfamethoxazole
Fluka
Decane
Fluka
Sulfonic acid
Fluka
Diclofenac sodium salt
Fluka
Sodium chloride
Fluka
Hydrochloric acid
Aldrich
Sodium hydroxide
Fluka
Oxalic acid dihydrate
Aldrich
Tetracycline
Fluka
Table 11.3: Materials used in this work
Material Supplier
Polyether-based Polyurethane foam (PUF),
density 30 kgm
-3
Euro foam GmbH Schaumstoffe Troisdorf,
Germany
Polyester-based Polyurethane foam (PUF)
K.G. Schaum ( stoffwerk, Kremsmunster,
Austria)
Polymeric membranes
Synthesis at university of Paderborn
Cellulose membrane filter (0.45 µm)
Merck
Filter paper circles 125 mm
Merck
11. Experimental 107
Table.11.4: Equipments used in this work
Equipment Supplier
Autosampler GINA50
Gynkotek/Munich/Germany
Isocratic pump P580
Gynkotek/ Munich /Germany
Isocratic pump P480
Gynkotek/ Munich/Germany
Isocratic pump 655-12 A
Merk-Hitachi
UV-Vis Detector 655 A
Merk-Hitachi
UV-UVD 160S/320S
Gynkotek/ Munich/Germany
UV-UVD 170S/340S
Gynkotek/ Munich/Germany
Analytical column Lichro CART RP18 (5µm,
250 x 4mm)
Merck
Analytical column Lichro 100 RP-18 (5µm,
250 x 2mm)
Merck
Analytical column Phenomenex 100 RP-18
(5µm, 250 x 2mm)
Merck
Digital-pH-meter 766 Calimatic
Knick/Berlin/Germany
Ultrasound equipment
Bandel sonorex/Berlin/Germany
Magnetic stirrers
H+P Labortechnik AG
Mechanical shaker
Edmund Bühler, SM-30 control
A rotary evaporator (IKA-WERK)
Heidolph, Germany
11.8 Instrumentation parameters (HPLC-UV methods)
11.8.1 Method I (Extraction of SFM, CBZ and ASFM by PUF membrane
Utilization: HPLC (Gynkotek), Pump P580 HPG, Merck T-6300
Detector: UVD170S/340S, Merk, Darmstadt, Germany, UV Wave length: 225 nm
Autosampler (Gilson-Aimed Model 231 equipped with Dilutor 402
Column: LichroCART 100 RP-18, 5µm, 250*4mm, Merck
Column temperature: 30
o
C
Mobile phase: 25 mmol/L KH
2
PO
4
: Acetonitrile 83:17 (v/v)
F.R: 1.0 mL/min
11. Experimental 108
Injection volume: 50µL
Retention data (R
t
) of analytes: SFM: 3.32, CBZ: 4.92, DCF: 10.63 and IBU: 11.08
min.
11.8.2 Method II for PUF membrane
Utilization: Gynkosoft Chromatography-Data-system, PCD Version 5.50, Gynoktek
HPLC, Peak Area method
Detector: UV Detector-UVD 160S/320S (Gynkotek), UV Wave length: 225 nm
Pump: 655A-12 Liquid Chromatograph (Merck/Hitachi)
Column: Lichrospher 100 RP-18, 5µm, 250
*
2 mm
Column temperature: 30
o
C
Mobile phase: H
2
O:CH
3
CN (62.5:37.5 (v/v)), 26 mmol/L of NaH
2
PO
4
F.R: 0.6 mL/min
Injection volume: 50µL
Retention data (R
t
) of analytes: ASFM: 10.45, SFM: 12.16, CBZ: 16.81 min
11.8.3 Method III for PUF membrane
Detector: UV-Vis Detector 655A, UV Wave length: 225 nm
Column: Lichro CART RP-18 (5µm, 250
.
4mm, Merck)
Column temperature: 30
o
C
Mobile phase: 25 mmol /L KH
2
PO
4
:acetonitrile 83:17 (v/v)
F.R: 1.0 mL/min
Injection volume: 50µL
Retention data (R
t
) of analytes: SFM: 3.32, CBZ: 4.92, DCF: 10.63 and IBU: 11.08
min
11.8.4 Method IV for recovery TCs from loaded PUF membrane
Detection: 267nm, UV-Vis Detector 340S
Column temperature: 30
o
C
Column: Phenomenex (5µm, 250
.
2mm)
Mobile phase A: H
2
O:CH
3
CN:HCOOH (89.9:10:0.1(v/v))
Mobile phase B: H
2
O:CH
3
CN:HCOOH (59.5:40:0.1(v/v))
F.R: 0.4 mL/min
11. Experimental 109
Injection volume: 20µL
Retention data (R
t
) of analytes: TC: 8.77, iso-CTC: 10.31 and CTC: 12.79 min
Gradient conditions:
Time, min
1.0
10
16
18
20
22
24
Mobile
-
phase B
(%)
20 50 60 50 20 10 10
11.8.5 Method V for extraction of TCs drugs by PUF
Detection: 267nm, UV-Vis Detector 340S
Column: Phenomenex (5µm, 250
.
2mm)
Column temperature: 30
o
C
Mobile phase A: H
2
O:CH
3
CN:C
2
H
2
O
4
(1800:200:2(v/v))
Mobile phase B: H
2
O:CH
3
CN:C
2
H
2
O
4
(200:1800:2(v/v))
F.R: 0.4 mL/min
Injection volume: 20µL
Retention data (R
t
) of analytes: TC: 6.89, iso-CTC: 8.72 and CTC: 10.95 min
Gradient conditions:
Time, min
1.0
1.5
10
15
19
30
Mobile -
phase B (%)
10 20 40 100 10 10
11.8.6 Method VI for block copolymer membrane
Utilization: Gynkosoft Chromatography-Data-system, PCD Version 5.50, Gynoktek
HPLC, Peak Area method
Pump: P 480 (Gynkotek)
Detector: UV Detector-UVD 170S/340S (Gynkotek)
Column: Lichrospher 100 RP-18, 5µm, 250
*
2 mm
Column temperature: 30
o
C
Mobile phase: H
2
O:CH
3
CN (50:50(v/v)), 0.6 mmol/L of NaH
2
PO
4
F.R: 0.7 mL/min
UV Wave length: 225 nm, 267 nm
Injection volume: 20µL
Retention data (R
t
) of analytes: TC: 3.76, SFM: 4.56, CBZ: 7.07, IBU: 19.33
11. Experimental 110
11.8.7 Method VII for recovery target drugs from block copolymer membrane
Pump: P 480 (Gynkotek)
Detector: UV Detector-UVD 655A
Column: Lichrospher 100 RP-18, 5µm, 250
*
4mm, Merck
Column temperature: 30
o
C
Mobile phase: H
2
O:CH
3
CN (50:50(v/v)), 0.6 mmol/L of NaH
2
PO
4
F.R: 0.7 mL/min
UV Wave length: 210, 270, 218, 222 nm
Injection volume: 20 µL
Retention data (R
t
) of analytes:
TC: 2.22, SFM: 4.28, CBZ: 6.66, IBU: 18.10
Note: Mobile phases were filtered through 0.45 µm cellulose membrane filter before
. use.
Drug
Detection wave length
ג
,
nm
TC 210
SFM 270
CBZ 218
IBU 222
11. Experimental 111
Fig. 11.3: HPLC-UV chromatograms for the selected drug metabolites and active
drugs by using different methods; a) method II, b) method IV, c) method VI
. and d) method VIII
11. Experimental 112
11.9 Identication analysis of ASFM:
11.9.1 Elemental analysis Data of Perkin-Elmer-2400:
C
12
H
13
N
3
O
4
S.(C,.H,.N,.S),.Mol.wt:.295.31
E.A.: Anal. Found: C, 48.56; H, 4.43; N, 14.20; calc. C, 48.81;.H, 4.44; N, 14.23.
11.9.2 NMR Data of (300MH
z
, DMSO-d
6
) of ASFM:
O
SH
2
N
O
O
N
NO
CH
3
COOH OH
OH
OH
a
b
c
d
efg
h
i
O
SH
2
N
O
O
N
NO
CH
3
COOH OH
OH
OH
1
2
3
4
56
2
'
3
'
4
'
5
'
1
''
2
''
3
''
4
''
5
''
6
''
Table 11.6:
13
C-NMR-data
13
C-Atome
∆ [ppm]
δ [ppm]*
Aromat
C
1
158.1 157.8
C
4
169.6 170.3
C
2
,C
6
133.5 130.9
C
3
,C
5
119.9 118.7
Isoxazol
C
2’
128.5 128.7
C
3’
95.9 92.9
C
4’
143.9 142.6
C
5’
12.5 12.8
Acetyl
C
7
15.8 16.0
C
8
24.5 27.5
*
Ref. [278], [279]
11.9.3 Data of MS (EI) m/z (IR) 1000, 70ev, 200
o
C:
H
H
CH
3
COHN
CH
3
COHN
7 8
Table 11.5:
1
H-NMR data
1
H-Atome
δ [ppm]
J [Hz]
J [Hz]*
δ [ppm]*
2H, d, H
a
-H
a’
7.53
J
ab
= 8.9
7.5
J
ab
= 8.80
2H, d, H
b
-H
b’
6.76
J
ab
= 8.9
6.6
J
ab
= 8.80
1H, s, H
d
6.19
6.1
3H, s, H
c
2.40
2.4
3H, s, H
c
2.10
2.2
*
Ref. [278], [279]
11. Experimental 113
256[M
+
] (100), 221(42), 231(15), 186(82), 150(30), 123(5), 110(12), 98(10)
11.9.4 IR Data of FTIR Sectrometer Nicolet P510:
IR(KBr disc): γ[cm
-1
], 2978, 1162,1679(γ
co
)
114
12. References
1. O.A.H. Jones, N. Voulvoulis, J.N. Lester, Human: Pharmaceuticals in the
aquatic environment; A review. Environ Technol, 2001, 22, pp.1383 -1395.
2. Eintrag von Arzneimitteln und Verhalten und Verbleib in der Umwelt,
Literaturstudie Fachbericht 2, Landesamt für Natur, Umwelt und
Verbraucherschutz Nordrhein Westfalen, Recklinghausen 2007.
3. F.R. Ungemach: Einsatz von Antibiotika in der Veterinärmedizin:
Konsequenzen und rationaler Umgang, Tierärztl. Prax., 1999, 27, pp. 335-340.
4. K. Fent, A. Weston, D. Caminada: Ecotoxicology of human pharmaceuticals;
Aquat Toxicol. , 2006, 10, 76(2), pp. 122-159.
5. T. Ternes: Pharmaceuticals and metabolites as contaminants of the aquatic
environment; An overview. J. Amer. chem. Soc., 2000, 219, pp. 301-309.
6. M. Richardson, J. Bowron: The fate of pharmaceutical chemicals in the aquatic
environment; J. Pharm. Pharmacol., 1985, 37, pp. 1-12.
7. G. Aherne, R. Briggs: The relevance of the presence of certain synthetic
steroids in the aquatic environment; J. Pharm. Pharmacol., 1989, 41, pp.
7735-7736.
8. ABC News: AP
probe finds drugs in drinking water, AP IMPACT.
Pharmaceuticals found in drinking water, Affecting Wildlife and may be
humans, (http://adcnews.go.com/US/ wire Stroryid=4416882), 2008.
9. H.H. Tabak, R. L. Bunch: Steroid hormones as water pollutants. I. Metabolism
of natural and synthetic ovulation-inhibiting hormones by microorganisms of
115
activated sludge and primary settled sewage; Dev. Ind. Microbiol. 1970, 11,
pp. 367-376.
10. U. Schwabe, D. Paffrath: Arzneiverordnungsreport 95, Aktuelle Daten, Kosten,
Trends und Kommentare. Drug prescribing report 95, Current data, costs,
trends and comments, Gustav Fischer Verlag; Stuttgart, Jena. 1995.
11. IMS Health chemical country profile, 2003.
12. O. A. H. Jones, N. Voulvoulis, J. N. Lester: Aquatic environmental assessment
of the top 25 English prescription pharmaceuticals; Water Research, 2002, 36,
pp. 5013-5022.
13. US Environmental Protection Agency, Estimation Program Interfac EPI, Suite,
version 3.10. Environmental Protection Agency, Office of pollution Prevention
and Toxics; Washington DC, USA. 2003.
14. M. Schlüsener, D. Löffler, T. Ternes: Knappe, Knowledge and need
assessment on pharmaceutical products in environmental waters; Operative
commencement: February 1
st
2007 Final data of the project: July 2008.
15. O. Jones, J. Lester, N. Voulvoulis : Pharmaceuticals: A threat to drinking
water?; Trends in Biotech, 2005, 23(4), pp.163-167.
16. F.S. Lauridsen, M. Birkved, L.P. Hansen, H.C. Lützh
Ø
ft, B. Halling-S
Ø
rensen:
Environmental risk assessment of human pharmaceuticals in Denmark after
normal therapeutic use; Chemosphere, 2000, 40, pp. 783-793.
17. H. Färber: Antibiotika im Krankenhausabwasser (Antibiotics in the hospital
sewage); Hyg. Med. 2002, pp. 27-35.
18. N. Vieno, T. Tuhkanen, L. Kronberg: Elimination of pharmaceuticals in sewage
treatment plants in Finland; Water Res. 2007, 41, pp. 1001-1012.
116
19. S. Kim, J. Cho, I. Kim, B. Vanderford, S. Snyder: Occurrence and removal of
pharmaceuticals and endocrine disruptors in South Korean surface, drinking,
and waste waters; Water Res., 2007, 41, 1013-1021.
20. C. Tixier, H. P. Singer, S. Olellers, S. R. Müller: Occurrence and fate of
Carbamazepine, Clofibric Acid, Diclofenac, Ibuprofen, Ketoprofen, and
Naproxen in surface waters; Environmental Sci. & Techn. 2003, 37, 6, pp.
1061- 1068.
21. T. Heberer: Tracking persistent pharmaceutical residues from municipal
sewage to drinking water; J. of Hydrology, 2002, 266, 3-4, pp. 175-189.
22. B. Halling-Sørensen, S. Nors Nielsen, P.F. Lanzky, F. Ingerslev: Occurrence
fate and effects of pharmaceutical substances in the environment; A review.
Chemosphere 1998, 36, 2, pp. 357-393.
23. Bundesverband für Tiergesundheit (BFT). Aus:
Schneidereit, Martin:
Antibiotikaeinsatz in der Veterinärmedizin-Situation in Deutschland und
anderen europäischen Veredelungsregionen, 2006, pp. 1-16
24. R. Andreozzi, R. Marotta, N. Paxeus: Pharmaceuticals in STP effuents and
their solar photodegradation in aquatic environment; Chemosphere, 2002, 50,
1319-1330.
25. T.A. Ternes: Analytical methods for the determination of pharmaceuticals in
aqueous environmental samples; TrAC Trends in Analytical Chemistry, 2001,
20, 8, pp. 419-434.
26. R. Alexy, K. Kümmerer: Antibiotics for human use. In: Reemtsma, T., Jekel, M.
(Eds.), Organic Pollutants in the Water Cycle; Wiley-VCH, Weinheim, 2006.
pp. 65–83.
117
27. N.S. Pressley, N. Carolina effort seeks to wipe out outhouses Washington
post, p. A03, Sunday, 25 April 1999. Available: http://search washigtonpost.com
(cited 31 August 1999).
28. M. Carballa, F. Omil, J.M. Lema, M. Llompart, C. Garcia-Jares, I. Rodriguez,
M. Gomez, T. Ternes: Behavior of Pharmaceuticals, cosmetics and hormones
in a sewage treatment plant; Water Res. 2004, 3812, pp. 2918-2926.
29. C.G. Daughton, T.A. Ternes: Pharmaceuticals and personal care products in
the environment: Agents of subtle change?; A review. Environ. Health Persp,
1999, 107, pp. 907-938.
30. T. Ternes: Occurrence drugs in German sewage treatment plants and rivers;
Water Res. 1998, 32, 11, pp. 3245-3260.
31. M. Bonner, K.G. Wiristen: The national Sewage Report Card (Number Two):
Rating the Treatment methods and discharges of 21 Canadian cities sierra
legal defense fund report. August 1999. Sierra legal defense fund, Toronto,
Ontario. Canada. Available: http://www.sierralegal.org/reports.htm.
32. K. Kümmerer, R.Alexy, J. Hüttig, A. Schöll: Standardized testes fail to assess
the effects of antibiotics on environmental bacteria; Water Res. 2004, 38, pp.
2111-2116.
33. B.H. Sørensen, S. E. J
Ø
rgensen: Drugs in the environment; Chemosphere,
2000, 40, 7, pp. 691-699.
34. K. Kümmerer: Pharmaceuticals in the environment, sources, fate, effects and
risks; Springer-Verlag: Berlin, 2001.
35. M. Liebig, J. F. Moltmann, K. Thomas: Evaluation of measured and predicted
environmental concentrations of selected human pharmaceuticals and
118
personal care products; ESPR- Environ Sci. & Poll. Res. 2006, 13(2), pp. 110-
119.
36. N. Al-Hadithi, M. Grote, B. Saad: Determination of drugs and metabolites in
water by use of liquid membrane systems and HPLC, The 10
th
Asian
conference on analytical sciences, 11
th
- 13
th
August 2009, (Qutra world trade
center) Kuala Lumpur, Malaysia.
37. D.W. Kolpin, E. T. Furlong, M. T. Meyer, E. M. Thurrman, S. D. Zaugg, L. B.
Barber, H. T. Buxton: Pharmaceuticals, hormones, and other organic
wastewater contaminants in U.S streams 1999-2000: National
reconnaissance, 2002, 36, pp. 1202- 1211.
38. P.H. Roberts, K. V. Thomas: The occurrence of selected pharmaceuticals in
wastewater effluent and surface waters of the lower Tyne catchment; Science
of total Environ. 2006, 356, pp. 143-153.
39. K.V. Thomas; M.J. Hiton: The occurrence of selected pharmaceutical
compounds in UK estuaries; Mar. Pollut. Bull., 2004, 49, 5/6, pp. 436-444.
40. D. Löffler, T.A. Ternes: Determination of acidic pharmaceuticals, antibiotics
and ivermectin in river sediment using liquid chromatography-tandem mass
spectrometry; J. of Chromatography A, 2003, 1021, 1-2, pp. 133-144.
41. S.K. Weigel, J.H. Hühnerfuss: Drugs and personal care products as ubiquitous
pollutants: occurrence and distribution of clofibric acid; caffeine and DEET in
the North Sea Sci. Total Environ., 2002, 295, 1-3, pp. 131-141.
42. R. Hirsch, T. Ternes, K. Haberer, K. Kratz: Occurrence of antibiotics in the
aquatic environment; The science of the Total Env., 1999, 225, pp. 109-118.
119
43. S. Weigel, A. Aulinger, R. Brockmeyer, H. Harms, J. Loffler, H. Reincke, R.
Schmidt, B. Stachel: Pharmaceuticals in the river Elbe and is tributaries;
Chemosphere, 2004, 57, 2, pp. 107-126.
44. T. Thaker: Pharmaceutical data elude researchers; Environ. Sci. Technol.,
2005, 139, 9, pp. 193-194.
45. K.G. Karthikeyan, M.T. Meyer: Occurrence of antibiotics in wastewater
treatment facilities in Wisconsin, USA; Sci. Of the Total Environ., 2006, 361,
1-3, pp.196-207
46. D.R. Dietrich, S.F. Webb, T. Petry: Hot spot pollutants: Pharmaceuticals in the
environment; 2002, 131, pp. 1-3.
47. H. Hutter, P. Wallner, H. Moshammer, W. Hart, R. Sattelberger, G. Lorbeer, M.
Kundi: Blood concentrations of polycyclic musks in healthy young adults;
Chemosphere, 2005, 59, pp. 487-492.
48. K. Berger, B. Petersen, H. Buening-Pfauc: Persistence of drugs occurring in
liquid manure in the food chain; Archiv für Lebensmittelhygiene, 1986, 37, 4,
pp. 99-102.
49. G. Gibson, P. Skett: Introduction to drug metabolism. Chapman and Hall.
London.
50. S. caccia: Metabolism of the newer antidepressants: An overview of the
pharmacological and pharmacokinetic implications; 1998, 34, 4, pp. 281-302.
51. C. Göbel, C. McArdell, A. Joss, H. Siegrist, W. Giger: Fate of sulfonamides,
macrolides, and trimethoprim in different wastewater treatment technologies;
Sci. Total Environ., 2007, 372, pp. 361-371.
120
52. D. Kolpin, E. Furlong, M. Meyer, E. Thurman, S. Zaugg, L. Barber, H. Buxton:
Pharmaceuticals, hormones, and other organic wastewater contaminants in
U.S. streams, 1999-2000: A national reconnaissance; Enviro. Science and
Technology, 2002, 6, 15, pp. 1202-1211.
53. M. Bataineh, J. Nolte, B. Kuhlmann, N. Zullei-Seibert, M. Borges, M. Grote:
Degradation behavior of selected pharmaceutical and their main metabolites in
system for slow sand filtration, Current Pharm. Anal. 2006, 2, pp. 313-322.
54. M. Sengl, S. Krezmer: Proficiency tests for pharmaceuticals in different waters,
2003, 8, pp. 523-529.
55. D. McDowell, M. M. Huber, M. Wagner, U. Gunten, T. Ternes: Ozonation of
carbamazepine in drinking water: Identification and kinetic study of major
oxidation products, Environ. Sci. Technol. 2005, 39, pp. 8014-8022.
56. H. Wenyi, E. R. Bennett, R. J. Letcher: Ozone treatment and the depletion of
detectable pharmaceuticals and atrazine herbicide in drinking water sourced
from the upper Detroit. River, Ontario, Canada, Water Res. 2006, 40, pp.
2259-2266.
57. J.P. Bound, N. Voulvoulis: Predicted and measured concentrations for
selected pharmaceuticals in UK rivers, Water Res. 2006, 40, pp. 2885-2892.
58. C. Hartig, T. Storm, M. Jekel: Detection and identification of sulphonamide
drugs in municipal waste water by liquid chromatography coupled with
electrospray ionisation tandem mass spectrometry, J. of Chromatography A,
1999, 854, 1-2, pp. 163-173.
59. T. Heberer, M. Adam: Transport and attenuation of pharmaceutical residues
during artificial groundwater replenishment, Environ. Chem. 2004, 1, pp. 22-
25.
121
60. W. Ahrer, E. Scherwenk, W. Buchberger: Determination of drug residues in
water by the combination of liquid chromatography or capillary electrophoresis
with electrospray mass spectrometry, J. of Chromatograhy A, 2001, 910, pp.
69-78.
61. S. Webb, T. Ternes, M. Gibert, K. Olejniczak: Indirect human exposure to
pharmaceuticals via drinking water, Toxicology Letters, 2003, 142, pp. 157-
167.
62. H.R. Buser, T. Poiger, M. Müller: Occurrence and fate of the pharmaceutical
drug diclofenac in surface waters: rapid photodegradation in a lake; Environ.
Sci. Technology, 1998, 32, 22, pp. 3449-3456.
63. M.E. Ares: The impacts of low levels of antibiotics on freshwater microbial
communities. University of London, 1999.
64. T. Heberer: Occurrence, fate and removal of pharmaceutical residues in the
aquatic environment: A review of recent research data, Toxico. Letters, 2002,
131, pp.5-17.
65. F. Sacher, f. Lange, H. Brauch, I. Blankenhorn: Pharmaceuticals in
groundwaters. Analytical methods and results of a monitoring program in
Baden- Württemberg, Germany. J. of Chromatography A, 2001, 938, pp. 199-
210.
66. H.R. Buser, T. Müller: Occurrence and environmental behaviour of the
pharmaceutical drug ibuprofen in surface waters and in wastewater. Environ.
Sci. Technol., 1999, 33, pp. 2529-2535.
67. T. Ternes, M. Bonerz, T. Schmidt: Determination of neutral pharmaceuticals in
wastewater and rivers by liquid chromatography-electrospray tandem mass
spectrometry, J. of Chromatography A, 2001, 938, pp. 175-185.
122
68. K. Kümmerer: Significance of antibiotics in the environment. J. Antimicrobial.
Chem, 2003, 52, pp.5-6.
69. X. Miao, C. Metcalfe: Determination of Carbamazepine and its Metabolites in
aqueous samples using liquid chromatography- electrospray tandem mass
spectrometry, Anal. Chem. 2003, 75, pp. 3731-3738.
70. W. Forth, D. Henschler; W. Rummel, K. Starke: Allgemeine und spezielle
Pharmakologie und Toxikologie, 6
th
ed. Wissenschaftsverlag Mammheim/
Leipzig/ Vienna/ Zurich, 1992.
71. W. Stelzer, E. Ziegert, E. Schneider: The occurrence of antibiotic-resistant
Klebsiellae in wastewater. Zentral Mikrobiol., 1985, 291, pp.140-283.
72. A. Malik, M. Ahmad: Incidence of drug and metal resistance in E. coil strains
from sewage water and soil. Chem Environ Res., 1994, 11, pp. 3-3.
73. M. Al-Ghazali, S. UJazrawi, Z. Al-Doori: Antibiotic resistance among pollution
indicator bacteria isolated from Al-Khair river, Baghdad. Water Res., 1988, 22,
pp. 641-644.
74. S. Pathak, A. Gautam, A. Gaur, K. Gopal, P. Ray: Incidence of transferable
antibiotic resistance among enterotoxigenic Escherichia coli in urban drinking
water. J. Environ Sci Health Part A, 1993, A28, pp. 1445-1455.
75. F. Sacher, E.
Lochow, D.
Bethmann, H. Brauch: Vorkommen von
Arzneimittelwirkstoffen in Oberflächengewässern: Vom Wasser, 1998, 90, pp.
233-243.
76. M. Stumpf, T. Ternes, K. Haberer, P. Seel, W. Baumann: Nachweis von
Arzneimittelrückständen in Kläranlagen und Fließgewässern: Vom Wasser,
1996b, 86,pp. 291-303.M.
123
77. E. Möhle, S. Horvath, W.
Merz, W. Metzger: Bestimmung von schwer
abbaubaren organischen Verbindungen im Abwasser-Identifizierung-
Bestimmung von Arzneimittelrückständen. In: Vom Wasser, 1999a, 92, 207-
223.
78. N. Mons, A. Hoogenboom, T. Noij: Pharmaceuticals and drinking water supply
in the Netherlands: In: KIWA N. V. Report BTO, 2003b.
79. L. Dsikowitzky, J. Schwarzbauer, R. Littke: The anthropogenic contribution to
the organic load of the Lippe River (Germany). Part II: Quantification of
specific organic contaminations: In: Chemosphere, 2004b, 57, 1289-1300.
80. S. Wiegel, H. Harms, B. Stachel, R. Schmidt, R. Brockmeyer, A. Aulinger, von
W. Tuempling: Arzneistoffe in Elbe und Saale. In: Arbeitsgemeinschaft für die
Reinhaltung der Elbe (Hrsg.), 2003.
81. S. Rögler, K. Prausa, B. Frank, A. Mechlinski, T. Heberer: Untersuchungen zu
Vorkommen und Verhalten von Antibiotika. In: Jahrestagung der
Wasserchemischen Gesellschaft in der Gemeinschaft deutscher Chemiker.
Bad Mergentheim 02-04. Mai 2005. Tagungsband, Bad Mergentheim, 2005,
pp. 415-420.
82. H. Robakowski: Arzneimittelrückstände und endokrin wirkende Stoffe in der
aquatischen Umwelt. In: Landesanstalt für Umweltschutz Baden-Württemberg
(Hrsg), 2000, 8, Karlsruhe.
83. N. Al-Hadithi: Determination of drugs and metabolites in water by use of liquid
membrane systems and HPLC method development and application.
Dissertation, University of Paderborn, 2007. pp. 67, 72.
84. S. Yang, J. Cha, C. Kenneth: Quantitative determination of trace
concentrations of tetracycline and sulfonamide antibiotics in surface water
124
using solid-phase extraction and liquid chromatography/ion trap tandem mass
spectrometry. RAPID Commun: Mass Spectrom. 2004, 18, pp. 2131-2145.
85. X. Weihai, G. Zhang, L. Xiangdong, Z. Schichun, L. Ping, H. Zhaohui, L. Jun:
Occurrence and elimination of antibiotics at four sewage treatment plants in
the Pearl River Delta (PRD), South China. Water Research 2007, pp. 4526-
4534.
86. T. Christian, R.Schneider, H. Färber, D. Skutlarek, M. Meyer, H. Goldbach:
Determination of antibiotics residues in manure, soil, and surface waters. Acta
Hydrochim. Hydrobiol. 2003, 31, 1, pp. 36-44.
87. D. Bendz, N. Paxeus, R. Timothy, F. Loge: Occurrence and fate of
pharmaceutically active compounds in the environment, a case study: Höje
River in Sweden. Hazardous Materials, 2005,122, pp. 195-204.
88. J. Roempp Lexikon Chemie –Version 2.0, Stuttgart/new York: Georg Thieme
Verlag 1999.
89. D.W.A. Bourne: Physical-Chemical factors affecting oral absorption, Chpter
12, 2000, pp. 2. http://www.boomer.org/c/p4/c12/c1202.html.
90. R. Pollet, C. Glatz, D. Dyer: The pharmacokinetics of chlortetracycline orally
administered to turkeys: Influence of citric acid and pasteurella multocida
infection. 2005, 13, 3, pp. 243-264.
91. S.A. Waksman: What is an antibiotic or an antibiotic substance?, Mycologyical
Society of America, 1947, 39, pp. 565-569.
http://www. Jstor.org/stable/3755196.
92. H. Auterhoff, J. Knabe, H.D. Höltje; In: Lehrbuch der Pharmazeutischen
Chemie; Wissenschaftliche Verlagesellschaft. Stuttgart; 13. Aufl.; 1994; 741-
795.
125
93. K.
Kümmerer: Significance of antibiotics in the environment.
J. Antimicrob. Chem. 2003, 52, 5–7.
94. K. Kümmerer: Pharmaceuticals in the Environment. Sources, Fate, Effects
and Risk, third. 2008. Springer, Berlin Heidelberg.
95. A. Famiglietti, S. Garcia, C. Vay, R. Torres: Neisseria gonorrhoeae drug
susceptibility in Buenos Aires. Argentina, APUA Newsletter, 2000, 18, 4.
http://www.tufts.edu/med/apua/patients/patient.htm.
96.
K. Elmund, S.M. Morrison, D.W. Grant, m. p. Nevins: Role of excreted
chlortetracycline in modifying the decomposition in feedlot waste. Bull.
Environ. Contam. Toxicol. 1971, 6, pp. 129-135.
97. S.E. Feinman, J.C. Matheson: Draft environmental impact statement sub
therapeutic and bacterial agents in animal feeds. Food and drug
Administration Department of Health, Education and welfare Report, 1978, pp.
372. Food and Drug Administration, Washington, D.C.
98. L. Donoho: Biochemical studies on the fate of monensin in animals and in the
environment, J. Anim. Sci. 1984, 58, pp. 1528-1539.
99. J. Gavalchin, S.E. Katz: The persistence of fecalborne antibiotics in soil, J.
Assoc. of Anal. Chem Int. 1994, 77, pp. 481-485.
100. E.R. Haapapuro, N.D. Barnard, M. Simon, Review- animal waste used as
livestock feed: dangers to human health, 1997, Prev. Med. 26, pp. 599-602.
101. J.M. Sweeten: Livestock and poultry waste management national overview,
American Society for Agricultural Engineering, 1992, pp. 4-15.
126
102. Geological Survey (U.S.): Groundwater - Research - United States. Groundwater -
United States - Quality. Wellhead protection - United States, 1995.
http://water.usgs.gov/wid/html/GW.html; current access is available via PURL.
103. L.G., Krapac, W.S. Dey, C.A. Smyth, W. R. Roy: Impacts of bacteria, metals,
and nutrients on groundwater at two hog confinement facilities, pp. 29-50. In
proceedings of the National Ground Water Association-animal Feeding
Operations and Groundwater: Issues, Impacts, and Solutions- A conference
for the Future. National groundwater association, St. Louis, Mo. 2007.
104. W. Krapac, S. Dey, W. R. Roy, B. G. Jellerichs, C. Smyth: Groundwater quality
near livestock manure pits, 2000, pp. 710-718. In 8th International Symposium
on Animal, Agricultural and Food Processing Wastes. American Society for
Agricultural Engineering, Des Moines, Iowa.
105. W. Beall: The use of organo- clays in water treatment. Appl. Clay Sci, 2006,
24, pp.11-20.
106. R.C. Wan: Interactions of tetracycline antibiotics with dissolved metal ions and
metal oxides; Chemistry Department, Faculty of Science, Georgia University,
2008.
107. E. Gontier, M.L. Teruel, J.E. Saucedo, J.N. Barbotin: High resolution HPLC
method with reverse phase C18 symmetry column for the analysis of
tetracyclines produced by Streptomyces aureofaciens immobilized in Ca-
alginate gel. Biotechnology Tech., 1996, 10, pp. 443-448.
108. R.
Sattelberger, O. Gans, E.
Martinez: Veterinärantibiotika in Wirtschaftsdünger
und Boden, In: Umweltbundesamt (Hrsg.), Wien, 2005, 272, pp.1-103.
109. J. Tolls: Sorption of veterinary pharmaceuticals in soils: A review, Enviro. Sci.
& Tech., 2001, 35, 17, pp. 3397-3405.
127
110. K. Kümmerer. Antibiotics in the aquatic environment. A review-part I,
Chemosphere, 2009, 75, pp. 417-434.
111. C. Winckler, A. Grafe: Use of veterinary drugs in intensive animal production-
Evidence for persistence of tetracyclines in pig slurry. J. of soils and
sediments, 2001, 2, 1, pp. 66-70.
112. M. Kuhne, D. Ihnen, G. Möller, O. Agthe: Stability of tetracycline in water and
liquid manure. J. Veterin. Medic. Series A- Physiology, Pathology and Clinical
Medicine, 2000, 47, pp. 379-384.
113. P. K. Jjemba: The potential impact of veterinary and human therapeutic agents
in manure and bio solids on plants grown on arable land, Agriculture
Ecosystems & Environment, 2002, 93, pp. 267-278.
114. A. Vockel: Bestimmung von Chlortetracyclinrückständen in biologischen
Proben aus der landwirtschaftlischen Tierhaltung mit HPLC-UV-MS/MS
Methodenentwicklung und Anwendung in Medikationsstudien, Dissertation;
Universität, Paderborn, 2005.
115. A. Göbel: Occurrence and fate of sulphonamide and macrolide antimicrobials
in wastewater treatment, Dissertation, Eidgenössische Technische
Hochschule ETH Zürich, Bonn, 2004.
116. H. Färber, D. Alberti, R. R. Reupert.: Belastung kommunaler Abwässer mit
Arzneimitteln aus medizinischen Einrichtungen. GWA Gewässerschutz,
Wasser, Abwasser, 2004, 193 , 24, pp.1-16.
117. S. Yang, K. Carlson: Routine monitoring of antibiotics in water and wastewater
with a radioimmunoassay technique. Water Res., 2004, 38, pp. 3155-3166.
118. J. Kues, H. Höper, H.T. Pawelzick, E. Pluquet, G. Hamscher: Results of
potential pollutants in the soil through manure. Effect on soil organisms and
128
relocation. Ministry of Environment and Conservation, Agriculture and
Consumer Protection of North Rhine-Westphalia, Unit IV.6 Association of Soil,
Soil-European and local: publication on the joint conference = Soil protection:
joint publication by the specialist conference (Environment), Berlin, 2004,
Düsseldorf, pp.55-62.
119. A. Grafe, Untersuchungen zum Einsatz pharmakologisch wirksamer Stoffe in
der Veredelungswirtschaft unter besonderer Berücksichtigung der
Tetracycline. Cuviller Verlag, Göttingen, 2000, 157 S.
120. G. Hamscher, S. Sczesny, H. Höper, H. Nau: Determination of persistent
tetracycline residue in soil fertilzed with liquid manure by high performance
liquid chromatography with electrospray ionization tandem mass spectrometry.
Anal. Chem. 2002, 74, 7, pp. 1509-1518.
121. G. Hamscher, H. Pawelzick, H. Höper, H. Nau: Tierarzneimittel in Böden- eine
Grundwassergefährdung.: Arzneimittel in der Umwelt - Zu Risiken und
Nebenwirkungen fragen Sie das Umweltbundesamt, Umweltbundessamt
(Hrsg.), 2005, 29, 05, pp. 175-184.
122. H. Sanderson, F. Ingerslev, R. A. Brain, B. Halling- Sørensen, J. K. Bestari,
C.J. Wilson; D.J. Johnson, K.R. Solomon: Dissipation of oxytetracycline,
chlortetracycline, tetracycline and doxycycline using HPLC-UV and LC/MS/MS
under aquatic semi-field microcosm condition. Chem., 2005, 60, pp. 619-629.
123. J. Kues, H. Höper, G. Hamscher,S. Sczesny, H. Nau: Gehalte von
Tierarzneimitteln in Wirtschaftsdüngern, Eintrag in Böden und Abbauverhalten.
KTBL-Schrift: Landwirtschaftliche Verwertung von Klärschlamm, Gülle und
anderen Düngern unter Berücksichtigung des Umwelt- und
Verbraucherschutzes, BMU/BMVEL (Hrsg.), 2002, 404, pp. 317-322.
129
124. A. B. Boxall, L.A. Fogg, P.A. Blackwell, P. Key, E. J. Pemberton, A. Croxford:
Veterinary medicines in the environment. Reviews of environmental
Contamination and Toxicology, 2004, 180, pp. 1-91.
125. H.C. Holten-Lützhøft, B. Halling-Sørensen, S.E. Jørgensen: Algae toxicity
ofantibacterial agents applied in Danish fish farming. Arch. Environ. Con.
Toxicol. , 1999, pp. 36, 1–6.
126. A.B. Boxall, L.A. Fogg, P. Kay, P.A. Blackwell, E.J. Pemberton, A. Croxford,:
Veterinary medicines in the environment. Rev. Environ. Contam. T. 2003, 180,
pp.1–91.
127. R.A. Brain, D. J. Johnson, S.M. Richards, H. Sanderson, P.K. Sibley, K.R.
Solomon: Effects of 25 pharmaceutical compounds to Lemna gibba using a
seven-day static-renewal test. Envir. Toxico. &Chem., 2004, 23, 2, pp. 371-
382.
128. L. Wollenberger, B. Halling-Sørensen, K.O. Kusk: Acute and chronic toxicity of
veterinary antibiotics to Daphnia. Chemosphere, 2000, 40, pp. 723-730.
129. C. Winckler, A. Grafe: Charakterisierung und Verwertung von Abfällen aus der
Massentierhaltung unter Berücksichtigung verschiedener Böden.
Umweltbundesamt (Hrsg.), UBA, 2000, 44/00, Berlin.
130. B. Halling-Sørensen, J. Jensen, J. Tjørnelund, M.H. Montforts: Worst-case
estimations of predicted environmental soil concentrations (PEC) of selected
veterinary antibiotics and residues used in Danish agriculture. (Hrsg.),
Pharmaceuticals in the environment, 2001, 1, pp.143-157.
131. H. Montforts, D.F. Kalf, L.A. Vlaardingen, J.B.H. Linders. The exposure
assessment for veterinary medicinal products. The science of the Total
Environment, 1999, 225, pp. 119-133.
130
132. C. Winckler, H. Engels, K. Hund-Rinke, T. Luckow, M. Simon, G. Steffens:
Verhalten von Tetracyclinen und anderen Veterinärantibiotika in
Wirtschaftsdünger und Boden, Forschungsbericht 29733911.
Umweltbundesamt (Hrsg.), Berlin, Band, 2004, 44.
133. S.E. Allaire, J.D. Castillo, V. Juneau: Sorption kinetics of chlortetracycline and
tylosin on sandy loam and heavy clay soils, J. Environ. Qual., 2006, 35, pp.
969-972.
134. S.A. Sassman, L.S. Lee: Sorption of three tetracyclines by several soils:
Assessing the role of pH and cation exchange. Environ. Sci. Technol., 2005,
39, pp. 7452-7459.
135. T. Søeborg, F. Ingerslev, B. Halling-Sørensen: Chemical stability of
chlortetracycline and chlortetracycline degradation products and epimers in
soil interstitial water. Chemosphere, 2004, 57, 6, pp. 1515-1524.
136. B. Halling-Sørensen, A. M. Jacobsen, G. Sengelöv, E. Vaclavik, F. Ingerslv:
Dissipation and effects of chlortetracycline and tylosin in two agricultureal
soils: A field–scale studying southern Denmark. Environ. Toxicol. and Chem.,
2005, 24, 4, pp. 802-810.
137. B. Halling-Sørensen, G. Sengelöv, J. Tjörnelund: Toxicity of tetracyclines and
tetracycline degradation products to environmentally relevant bacteria,
including selected tetracycline-resistant bacteria. Archives of Environmental
Contamination and Toxicology, 2002, 42, pp. 263-271.
138. S. Thiele-Bruhn: Pharmaceutical antibiotic compounds in soils- A review, J.
Plant Nutrition and Soil Science, 2003, 166, pp. 145-167.
139. B. Halling-Sørensen: Algae toxicity of antibacterial agents used in intensive
farming, Chemosphere, 2000, 40, pp. 731-739.
131
140. P. Segura, M. Francois, C. Gagnon, S. Sauve: Review of the occurrence of
anti-infectives in contaminated wastewaters and natural and drinking waters;
Review, Environmental Health Perspectives, 2009, 117, 5, pp. 675-684.
141. A.L. Batt, M.S. Kostich, J.M. Lazorchak: Analysis of ecologically relevant
pharmaceuticals in wastewater and surface water using selective Solid-Phase
extraction and UPLC-MS/MS, Anal. Chem., 2008, 80, 13, pp. 5021-5030.
142. IMS Health AG: Chemical Country Profile Germany, 2002, 2000 - 2001.
143. E. Mutschler, G. Geisslinger, H.K. Kroemer, M. Schäfer-Korting:
Arzneimittelwirkungen: Lehrbuch der Pharmakologie und Toxikologie, 2001, 8.
Auflage. Wissenschaftliche Verlagsgesellschaft, Stuttgart.
144. A. Al- Ahmad, F. D. Daschner, K. Kümmerer: Biodegradability of cefotiam,
ciprofloxacin, meropenem, penicillin G and sulfamethoxazole and inhibition of
waster water bacteria. Archives of Environmental Contamination and
Toxicology, 1999, 37, 2, pp.158-163.
145. K. Kümmerer, A. Henninger: Promoting resistance by the emission of
antibiotics from hospitls and household into effluent. Clinical Microbiology &
Infection, 2003, 9, pp.1203-1214.
146. H.A. Färber, D. Skutlarek, M. Exner: Untersuchung von
Krankenhausabwässern eines Universitätsklinikums, von kommunalem
Abwasser sowie von Oberflächenwasser und Uferfiltraten auf Rückstände
ausgewählter Antibiotika. Institut für Hygiene und Öffentliche Gesundheit
Universität Bonn(Hrsg.) 2001, pp. 1-131, Abschlussbericht zum
Forschungsprojekt im Auftrag des Landesumweltamts NRW, LUANRW 112-
1781/MZ 43/99 und LUA NRW 112-1781/MZ2/2000.
132
147. J.E. Ongerth, S. Khan: Drug residuals: How xenobiotics can affect water
supply sources, Journal of American Water Works Association, 2004, 95, 5,
pp. 94-101.
148. W. Schüssler, M. Sengl: Arzneimittel in der Umwelt. F+E- Vorhaben 2000-
2002, Kennnummer 73e 04010049. Bayrisches Landesamt für
Wasserwirtschaft (Hrsg.), Materialien, 2004, pp. 114.
149. K. Kümmerer: Resistance in the environment; Journal of Antimicrobial
Chemotherapy, 2004, 54, pp. 311- 320.
150. Rückstände von Arzneimitteln in Wasserproben-Befunde und deren
Bewertung aus Sicht der Trinkwasserversorgung, DVGW-Schriftenreihe
Wasser Nr. 94. 2000.
151. T. Christian, R.J. Schneider, H.A. Fäber, D. Skutlarek, M.T. Meyer, H.E.
Goldbach: Determination of antibiotic residues in manure, soil, and surface
waters, Actahydrochimica et hydrobiologica, 2003b, 311, pp.36-44.
152. L. Boreen, W.A. Arnold, K. McNeill: Photochemical fate of sulfa drugs in the
aquatic environment: Sulfa drugs containing five-membered heterocyclic
group, Environmental Science and Technology, 2004, 38, 14, pp. 3933-3940.
153. P. Drillia, K. Stamatelatou, G. Lyberato: Fate and mobility of pharmaceuticals
in solid matrices, Chemosphere, 2005, 60, pp. 1034-1044.
154. F.F. Reinthaler, J. Posch, G. Feierl, G. Wüst, D. Haas, G. Rückenbauer, F.
Mascher, E. Marth: Antibiotic resistance of E. coli in sewage and sludge,
Water Research, 2003, 37, pp. 359-364.
155. http://www.cas.org./SCIFINDER/SCHOLAR/.
133
156. J.P. Bound and N. Voulvoulis: Household disposal of pharmaceuticals as a
pathway for aquatic contamination in the United Kingdom; Environmental
Health Perspectives, 2005, 113, pp. 1705- 1711.
157. E. Isidori, M. Lavorgna, A. Nardelli, L. Pascarella, A. Parrella: Toxic and
genotoxic evaluation of six antibiotic on non-target organisms, The Sci. of the
Total Environment, 2005, 346, pp. 87-98.
158. M.
.
Liebig:.Untersuchungen.zu
.
Umweltrisikobschätzungen.von:Humanpharmak
a und Inhaltsstoffen von Körperpfegeprodukten vor dem Hintergrund
europäischer Bewertungskonzepte, Dissertation, Johann Wolfgang Goethe-
Universität Frankfurt, 2005, 220 S.
159. J.G. Ochoa, W. Riche: Antiepileptic Drugs, 2009. http:// emedicine.
Medscape.com/article/1187334-overview.
160. Roche Pharma (Schweiz) AG (2002): Fachinformation Bactrim® Orale
Formen. http:// www.ROCHE online lexicon medicine.
161. U. Schwabe, D. Paffrath: Arzneiverordnungs-Report 1999. Aktuelle Daten,
Kosten, Trends und Kommentare, Springer-Verlag, 2000, Berlin, Heidelberg,
New York.
162. BLAC (Bund/ länderausschuss für Chemikaliensicherheit): Arzneimittel in der
Umwelt- Auswertung der Untersuchungsergebnisse, 2003, Freie und
Hansestadt Hamburg- Behörde für Umwelt und Gesundheit.
www.blac.de/servlet/is/2146/P-2c.pd.
163. J.C. Duran-Alvarez, E.B. Bravo, V.S. Castro, B. Jimenez, R. Gibson: The
analysis of a group of acidic pharmaceuticals, carbamazepine, and potential
endocrine disrupting compounds in wastewater irrigated soils by gas
chromatography-mass spectrometry, Talanta, 2009, 78, pp. 1159-1166.
134
164. K. Lertratanangkoon, M. Horning: Metabolism of carbamazepine, Drug
Metabolism and Disposition, 1981, 10, pp. 1-10.
165. Novartis: Tegretol, carbamazepine USP; prescribing information. Novartis
Pharmaceuticals Corporation, 2000, East Hanover, New Jersey, USA.
166. O.
Pelkonen, P. Myllynen, P. Taavitsainen:
Carbamazeoine: A blind
assessment of CYP- associated metabolism and interactions in human liver-
derived in vitro systems, Xenobiotica, 2001,31,6, pp.321-343.
167. S. Wiegel, H. Harms, B. Stachel, R. Brockmeyer, R. Schmidt, A. Aulinger:
Arzneistoffe in Elbe und Saale, Arbeitsgemeinschaft für die Reinhaltung der
Elbe (Hrsg.), 2003.
168. T.E. Doll, F.H. Frimmel: Verhalten von Carbamazepin, Clofibrinsäure,
Iomeprol und Iopromid in der Umwelt- Fotochemischer Abbau mittels
simulierter solarer UV-Strahlung, Vom Wasser, 2003, 100, pp.99-110.
169. T.A. Ternes, J. Römbke: Behaviour of selected human and veterinary
pharmaceuticals in aquatic compartments and soil, Umweltbundesamt (Hrsg.),
2005, Texte 05/05, Förderkennzeichen 29967401/01, Berlin.
170. M. Clara, B. Strenn, N. Kreuzinger: Carbamazepine as a possible
anthropogenic marker in the aquatic environment: Investigations on the
behaviour of carbamazepine in wastewater treatment and during groundwater
infiltration, Water Res., 2004b, 38, pp. 947-954.
171. D. Löffler, J. Römbke, M. Meller, T.A. Ternes: Environmental fate of
pharmaceuticals in water/sediment system, Environmental Science and
Technology, 2005, 39, pp. 5209-5281.
172. F. Spengler, J.W. Metzger: Organische Spurenstoffe- Restemissionen aus
Kläranlagenabläufen. Hormonell wirksame Substanzen: Analytik und
135
Ergebnisse für Abwässer, Pharmaka und Hormone in der aquatischen Umwelt
- eine Bedrohung?. Hydrochemisches und Hydrobiologisches Kolloquium am
14.03.2002. Stuttgarter Berichte zur Siedlungswasserwirtschaft., Forschungs-
und Entwicklungsinstitut für Industrie- und Siedlungswasserwirtschaft sowie
Abfallwirtschaft e. V. (Hrsg.), 2002, Band 168, Stuttgart, 25-33.
173. L. Dsikowitzky, J. Schwarzbauer, R. Littke: The anthropogenic contribution to
the organic load of the Lippe River (Germany). Part II: Quantification of
specific organic contaminations, Chemosphere, 2004 b, 57, pp. 1289-1300.
174. BLAC: Arzneimittel in der Umwelt - Auswertung der Untersuchungsergeb-
nisse, Bund/Länderausschuss für Chemikaliensicherheit (BLAC) (Hrsg.),
Hamburg, 2003, pp. 1-41.
175. T.A. Ternes: Abbau und Verhalten von Pharmaka in aquatischen Systemen,
Schriftenreihe Wasserforschung Bd. 6: Chemische Stressfaktoren in
aquatischen Systemen, B. Weigert, C. Stenberg, R. Büggemann (Hrsg.), Band
6, Wasserforschung e. V., Berlin, 1998c, pp. 23-33.
176. B. Ferrari, N. Paxeus, R. Giudice A. Pollio, J. Garric: Ecotoxicological impact
of pharmaceuticals found in treated wastewaters: Study of carbamazepine,
clofibric acid, and diclofenac, Ecotoxicology and Environmental Safety, 2003,
55, pp. 359-370.
177. M. Cleuvers: Aquatische Ökotoxikologie ausgewählter Arzneimittel: UWSF-
Zeitschrift für Umweltchemie und Ökotoxikologie, 2002, 14(2), pp. 85-89.
178. M. Cleuvers: Mixture toxicity of pharmaceuticals including the assessment of
combination effects, Toxicology Letters, 2003,142, pp. 185-194.
179. B. Hanisch, B. Abbas, W. Kratz: Ökotoxikologische Bewertung von
Humanarzneimitteln in aquatischen Ökosystemen. Studien und
136
Tagungsberichte. Landesumweltamt Brandenburg (Hrsg.), 2002 b, Band 39,
Frankfurt.
180. M. Oetken, G. Nentwig, D. Löffer, T. Ternes, J. Oehlmann: Effects on
pharmaceuticals on aquatic invertebrates. Part I. The antiepileptic drugs
Carbamazepine, Arch. Environ. Contam. Toxicol., 2005, 49, pp. 353-361.
181. IMS Health AG (2002): Chemical Country Profile Germany 2000-2001. www.
Fda.gov/CDER7DRUG/Analgesia_antiinflam/default.htm.
182. T. Poiger, H. Buser, M. Müller: Photodegradation oft he pharmaceutical during
dicllofenac in a lake: Pathway, filed measurements, and mathematical
modeling, Environ. Toxicol. Chem., 2001, 20, (2), PP.19-28.
183. W. Degen,. W. Dieterle, W. Schneider, U. Theobald: Pharmacokinetics of
diclofenac and five metabolites after single dose in healthy volunteers and
after repeated doses in patients, Xenobiotica, 1988, 18, 12, pp. 1449-1455.
184. J.E. Ongerth, S. Khan: Drugs residuals: How xenobiotics can affect water
supply sources, J. of American Water Works Association, 2004, 95, 5, pp. 94-
101.
185. W. Lilienblum, W. Bülow, V. Herbst, B. Jandel, K. Müller: Endokrin wirksame
Schadstoffe (EWS) und pharmakologisch wirksame Stoffe in aquatischen
Bereichen Niedersachsens, Nachhaltiges Niedersachsen 11. Dauerhaft
umweltgerechte Entwicklung, Niedersächsisches Landesamt für Ökologie
(Hrsg.), Band 11, 1. Auflage, Hildesheim, 1998, pp. 1-40.
186. F.
..
Ingerslev, B. Halling-Sørensen: Biodegradibility of metronidazole,
olaquindox and tylosin and formation of tylosin degradation products in aerobic
soil/manure slurries. Chemosphere, 2001, 48, pp. 311-320.
137
187. H.P. Singer, C. Tixier, S. Oellers, S.R. Müller: Occurrence and fate of
carbamazepine, clofibric acid, diclofenac, ibuprofen, ketoprofen, and naproxen
in surface waters, Environmental Science and Technology, 2003, 37,6, pp.
1061-1068.
188. P. Mersmann: Transport-und Sorptionsverhalten der Arzneimittelwirkstoffe
Carbamazepin, Clofibrinsäure, Diclofenac, Ibuprofen und Propyphenazon in
der wassergesättigten und -ungesättigten Zone. Disseration, Technische
Universität Berlin, 2003.
189. J. Römbke, T. Knacker, A. Stahlschmidt: Umweltprobleme durch Arzneimittel-
Literaturstudie, Umweltbundesamt (Hrsg.), For
schungsbericht
10604121.1996, 60, Berlin, 1-341.
190. R. Kreuzig, S. Höltge, J. Brunotte, N. Berenzen, J. Wogram, R. Schulz: Test-
pilot studies on runoff of sulfonamides from manured soils after sprinkler
irrigation, Environmental Toxicology and Chemistry, 2005 a, 24, 4, pp. 777-
781.
191. H. Robakowski: Arzneimittelrückstände und endokrin wirkende Stoffe in der
aquatischen Umwelt, Landesanstalt für Umweltschutz Baden-Württemberg
(Hrsg.), 2000, Band 8, Karlsruhe.
192. F. Sacher, E. Lochow, D. Bethmann, H. Brauch; Vorkommen von Arzneimittel-
wirkstoffen in Oberflächengewässern, Wasser, 1998, 90, pp. 233-243.
193. M. Stumpf, T.A. Ternes, K. Haberer, P. Seel, W. Baumann: Isolierung von
Ibuprofen-Metaboliten und deren Bedeutung als Kontaminanten der
aquatischen Umwelt, Wasser, 1998, 91, pp. 291303.
194. J. Brauch, M. Fleig, F. Sacher, W. Kühn, K. Lindner: Der Rhein im Jahr 2001,
Dvgw- Technologiezentrum Wasser (TZW)/ Arbeitsgemeinschaft Rhein-
Wasserwerke (Hrsg.), Karlsruhe/Köln, 2001, pp. 32-38.
138
195. J. Schwaiger, R. Negele: Ökotoxikologische Auswirkungen von Arzneimitteln.
Langzeitwirkungen bei Fischen, Abschlussbericht des Bayerischen
Landesamts für Wasserwirtschaft zum Forschungs -und
Entwicklungsvorhaben 2001-2003, 2004.
196. R. Triebskorn, H. Casper, A. Heyd, R. Eikemper, H. Köhler, J. Schwaiger:
Toxic effects of the nonsteroidal anti-inflammatory drug diclofenac. Part II:
Cytological effects in liver, kidney, gills, and intestine of rainbow trout
(Oncorhynchus mykiss), Aquatic Toxicology, 2004, 68, pp. 151-166.
197. HSDB-Hazardous Substances Data Bank: Produced by: Us National Library of
Medicine, Provided by: Canadian Centre of Occupational Health and Safety,
2001, 3.
198. W. Martindale: Ibuprofen- the complete drug reference, 2002, 33rd Ed.,
pharmaceutical press, London.
199. T.W. Hermann, E. Flig: Determination of ibuprofen and its metabolites in
biological fluids by high-performance liquid chromatography; Chem. Anal.
(Warsaw), 1995, 40, pp. 543-548.
200. F. Stuer-Lauridsen, M. Birkved, L.p. Hansen, H.-C. Holten Lützhöft, B. Halling-
S
Ø
rensen: Environmental risk assessment of human pharmaceuticals in
Denmark after normal therapeutic use, Chemosphere, 2000, 40, pp. 783-793.
201. B. Hanisch, B. Abbas, W. Kratz, G. Schürmann: Humanarzneimittel im
aquatischen Ökosystem. UWSF-Zeitschrift für Umweltchemie und
Ökotoxikologie, 2004, 16, 4, pp. 223-238.
202. P. Ivashechikin: Literaturauswertung zum Vorkommen gefährlicher Stoffe im
Abwasser und in Gewässern, Bericht zum Vorhaben im Auftrag des
Ministeriums für Umwelt und Naturschutz, Landwirtschaft und
139
Verbraucherschutz NRW, Az IV 042059, Institut für Siedlungswasserwirtschaft
(Hrsg.), 2005, Aachen.
203. R. Smith: Before the injection- modern methods of sample preparation for
separation techniques, Review, Journal of Chromatography A, 2003, 1000, pp.
3-27.
204. T. Heberer, K. Schmidt-Bäumler, H.J. Stan: Occurrence and distribution of
organic contaminants in the aquatic system in Berlin. Part I: Drug residues and
other polar contaminants in Berlin surface and groundwater, Acta
hydrochimica hydrobiologica, 1998, 26, 5, pp.72-278.
205. J. Jönsson and L. Mathiasson: Liquid membrane extraction in analytical
sample Preparation. II. Applications; Trends in analytical chemistry, 1999, 18,
pp. 325- 334.
206. H. Lord, J. Pawliszyn: Microextraction of Drugs; Review, Journal of
Chromatography A, 2000, 902, pp. 17-63.
207. T. Hyötyläinen: Critical evaluation of sample pretreatment techniques.
Analytical and Bioanal. Chem., 2009, 394, pp. 743-758.
http://www.springerlink.com/content/p324227824533275.
208. T. Braun, A. Farag, J. Navratil: Polyurethane foam sorbents in separation
chemistry; CRC Press, Boca Raton, 1985, pp. 4-10.
209. J. Jönsson and L. Mathiasson: Membrane extraction in analytical chemistry,
Review; Sep. Sci., 2001, 24, pp. 495-507.
210. J. Jönsson and L. Mathiasson: Membrane extraction for sample preparation,
Sample Preparation Perspectives; LC.GC Europe, October, 2003.
140
211. V.A. Lemos, D.R. Vieira, C.G. Novaes, M.E. Rocha, M.S. Santos R. T.
Yamaki: Preconcentration systems using polyurethane foam /Me-BDBD for
determination of copper in food samples, Microchim Acta., 2005.
212. M. Gama, A. Da. Lima V. Azevedo: Preconcentration system for cadmium and
lead determination in environmental samples using polyurethane foam/Me-
BTANC, J. Hazardous Materials, 2006, pp. 1-15.
213. M.F. El-Shahat, E.A. Moawed, A.B. Farag: Chemical enrichment and
separation of uranyl ions aqueous media using novel polyurethane foam
chemically grafted with different basic dyestuff sorbents, Talanta, 2007, 71, pp.
236-241338.
214. S.S. Feng:
Vitamin
E
TPGS
used
as
emulsifier
in
the solvent
evaporation/extraction technique for fabrication of polymeric nanospheres for
controlled release of paclitaxel, J. Contr. Release 2002, 80 (1-3), pp. 129-144.
215. F. Sannino, M. Iorio, A. De Martino, M. Pucci, C.D. Brown, R. Capasso:
Remediation of waters contaminated with ionic herbicides by sorption on
polymerin, Water Res., 2008, 42, pp. 643-652.
216. L. Chimuka, E. Cukrowska, J. Å. Jönsson: Why liquid membrane extraction is
an attractive alternative in sample preparation. Pure App. Chem. 2004, 76, pp.
707-722.
217. B. Kurtulus:
Anreicherung und Bestimmung von Arzneistoffspuren in
Wässern mit Flüssigmembransystemen und HPLC-MS, Dissertation,
Universität Paderborn, 2005.
218. Q. Sun, O.A. Alexandrova, P. Herckes, J.O. Allen: Quantitative extraction of
organic tracer compounds from ambient particulate matter collected on
polymer substrates. Talanta, 2009, 78, pp. 1115-1121.
141
219. A. Ameli, N. Alizadeh: Headspace solid-phase microextraction using a
dodecylsulfate-doped polypyrrole film coupled to ion mobility spectrometry for
the simultaneous determination of atrazine and ametryn in soil and water
samples, Talanta, 2009, 78, pp. 1107-1114.
220. M.F. El-Shahat, E. A. Moawed, M.A.A. Zaid: Preconcentration and separation
of iron, zinc, cadmium and mercury, from waste water using Nile blue a grafted
polyurethane foam. Talanta, 2003, 59, pp. 851-866.
221. R.J. Cassella, V.A. Salim , L.S. Jesuino, R.E. Santelli, S.L. Ferreira, M.S.
Carvalho: Flow injection determination of coblat after its sorption onto
polyurethane foam loaded with 2- (2- thiazolylazo)-p-cresol (TAC). Talanta,
2001, 54, pp. 61-67.
222. T. Vasudevan, S. Das, S. Sodaye, A.K. PandeyA. V.R. Reddy: Pore-
functionalized polymer memberanes for preconcentration of heavy metal ions,
Talanta, 2009, 78, pp.171-177.
223. K.B. Borges, E.F. Freire, I. Martins: Simultaneous determination of
multibenzodiazepines by HPLC/UV: Investigation of liquid- liquid and solid-
phase extractions in human plasma, Talanta, 2009, 78, pp. 233-241.
224. J.R. Dean, Extraction methods for environmental analysis. John Wiley &Sons,
Chichester 1998.
225. R.W. Baker: Membrane technology and applications, Menlo Park, California,
second edition, 2004. incomplete
226. S.G. Dmitrienko, L. N. Pyatkova, O. M. Medvedeva, Yu. A. Zolotov:
Preconcentration of organic compounds on foamed polyurethanes: regularities
and examples of analytical application, J. Anal. Chem., 2003, 58, pp. 614-618.
142
227. J.D. Moody, J.D. Thomas: Chromatographic separation and extraction with
foamed plastics and rubber; Marcel Deekker, Inc., Newyork, 1982, pp. 84-90.
228. H.J. Bowen: Absorption by polyurethane foams; new method of separation; J.
Chem. Soc. A, 1970, 1082-.1090.
229. H.D. Gesser, A. Chow, F.C. Davis, J. f. Uthe, J. Reinke: The extraction and
recovery of polychlorinated biphenyls (PCB) using porous polyurethane foam;
J. Anal. Lett, 1971, 4(12), pp. 883-886.
230. T. Braun, A. Farag: Foam chromatography. Solid foams as supports in
column chromatography; Talanta, 1972, 19, pp. 828- 830.
231. T. Braun: Spherical solid polyurethanes in sepration chemistry: polyurethane
foams as sorbents. Recent advances; Anal. Chem., 1989, 333, 785-792.
232. C.J. Spaans, V. W. Belgrver, O. Rienstra, J. H. de. Groot, R. P. H. Vetn, A. J.
Pennings: Solvent-free fabrication of micro-porous polyurethane amide and
polyurethane-urea scaffolds for repair and replacement of the knee-joint
meniscus, Biomaterials, 2000, 21, pp. 2453-2460.
233. B. Raymond, B. Seymour George, J. Kauffmann: Polyurethanes: A class of
modern versatile materials; Chem. Ed. 1992, 69, pp. 909-911.
234. S. Palȃgyi, T. Braun: Unloaded polyether type polyurethane foams as solid
extractants for trace elements; J. of Radioanalytical and Nulear Chemistry,
1992, 163, pp. 69-79.
235. S. Gross: Modern plastics encyclopaedia, McGraw-Hill, New York, 1969, 46,
pp. 248-250.
236. D. Randall, L. Steve, Polyurethanes Book. New York, 2002, Wiley. ISBN 0-
470-85041-8.
143
237. K. Hashimoto, H. Hasegawa, S. Bull. Res. Inst. Min. Dress Meiall. Tohoku
Univ., 1987, 43, pp.7.
238. T. Braun, M. Abbas, A. Alek: Reagent-loaded and unloaded polyurethane
foam as a preconcentration matrix in neutron activation analysis; J. Radioanal.
Chem., 1981, 67, pp. 359-365.
239. M. El-Shahat, E. A. Moawed, A. B. Farag: Chemical enrichment and
separation of uranyl ions in aqueous media using novel polyurethane foam
chemically grafted with different basic dyestuff sorbents, Talanta, 2007, 71, pp.
236-241.
240. S.G. Dmitrienko, L.N. Pyatkova, Yu.A. Zolotov: Sorption of Ion Associates on
polyurethane foams and application to sorption-spectroscopic and test
methods of analysis; J. Anal. Chem. 2002, 57pp. 1036-1942.
241. R. Werbowesky, A. Chow: Extraction of azo dyes by polyurethane foam;
Talanta, 1996, 43, pp. 263-274.
242. L. Schumak A.Chow: Extraction of aromatic organic compounds by
polyurethane foam; Talanta, 1987, 34, pp. 957-962.
243. S.G. Dmitrienko, Yu.A Zolotov: Polyurethane foam in chemical analysis:
sorption of various substances and its analytical applications; Russian
Chemical Reviews, 2002, 71, pp.159-174.
244. C. Nerin, A. Garnical, J. Cacho: Analysis of drugs by AAS via formation of ion
pairs; A. Mikrochim. Acta, 1986, 3, pp. 117-126.
245. T. Braun, S. Palagyi: Pulsting column separations with a polyurethane foam
syringe; Anal. Chem., 1979, pp.1697- 1685.
144
246. M. Bhaskar, P. Arunna, R. Jeevan, G. Radhakrishnan: β- Cyclodextrin-
polyurethane polymer as solid phase extraction material for the analysis of
carcinogenic aromatic amines; Analy. Chim. Acta, 2004, 509, pp. 39-45.
247. R.L. Maddalena, T. E. Mckone, N. Y. Kado: Simple and rapid extraction of
polycyclic aromatic hydrocarbons collected on polyurethane foam adsorbent;
Atmo. Enviro. 1998, 32, 14/15, pp. 2497-2503.
248. M.S. El-Shahawi, S.M. Aldhaheri: Preconcentration and separation of
caricides by polyether based polyurethane foam; Analy. Chim. Acta, 1996,
320, pp. 277-287.
249. M.S. El-Shahawi, H.A. Nassif: Kinetics and retention characteristics of some
nitrophenols onto polyurethane foams; Analy. Chim. Acta, 2003, 487, pp. 249-
259.
250. B. Farag, M.S. El-Sahawi: Removal of organic pollutants aqueous solution; J.
of Chromatography, 1991, 552, pp.371-379.
251. B. Farag, M.S. El-Sahawi, A.M. El-Wakil: Collection and separation of some
organic insecticides on polyurethane foam columns; Anal. Chem., 1986, 324,
59-60.
252. S.G. Dmitrienko, E.N. Shapovalova, E.Ya. Gurarii, M.V. Kochetova, O.A.
Shpigun, Yu.A. Zolotov: Preconcentration of polycyclic hydrocarbons on
polyurethane foam and their determination in waters with the use of
luminescence and high-performance liquid chromatography; J. Anal. Chem.,
2002, 57, pp. 1009-1016.
253. K.M. Gough H. D. Gesser: The extraction and recovery of phthalate esters
from water using porous polyurethane foam; J. of Chromatography, 1975, 115,
pp. 383-390.
145
254. P. Fong, A. Chow: Extraction of aromatic acids and phenols by polyurethane
foam; Talanta, 1992, 39, 5, pp. 497-503.
255. Å. Marand, D. Karlsson, M. Dalene, G. Skarping: Extractable organic
compounds in polyurethane foam with special reference to aromatic amines
and derivatives thereof, Analy. Chim. Acta, 2004, 510, 1, pp. 109-119.
256. N. Myshak, S.G. Dmitrienko, E.N. Shapovalova, A.V. Zhigulev, O. A. Shpigun,
Yu.A. Zolotov: Preconcentration of phenols on polyurethane foam and their
determination using spectrophotometry and high-performance liquid
chromatography; J. Analy. Chem., 1997, 52, 10, pp. 939-943.
257. O. Ibrahim: Qualitative and quantitative determinartion of some trace metal
ions using polyurethane foams immobilizing selective reagents, Dissertation,
University of Helwan, 2004.
258. P.T. Sukhanov, S.P. Kalinkina, Ya.I. Korenman: Extraction preconcentration of
naphthols and phenol with solvent mixtures impregnated into polyurethane
foam; J. Analy. Chem., 2004, 59, 12, pp.1153-1157.
259. K.L. Salipira, B.B. Mamba, R.W. Krause, T.J. Malefetse, S.H. Durbach:
Cyclodextrin polyurethanes polymerised with carbon nanotubes for the
removal of organic pollutants in water; Water SA, 2008, 34,1,
hptt://www.wrc.org.za.
260. S.D. Mhlanga, B.B. Mamba, R.W. Krause, T. J. Malefetse: Removal of organic
contaminants from water using nanosponge cyclodextrin polyurethanes; J.
Chem. Technology and Biotechnology, 2007, 82, pp. 382-388.
261. S. Das, A.K. Banthia, B. Adhikari: Removal of chlorinated volatile organic
contaminants from water by pervaporation using a novel polyurethane urea-
poly (methyl methacrylate) interpenetrating network membrane; Chem. Eng.
Sci., 2006, 61, pp. 6454-6467.
146
262. M.S. El-Shahawi: Retention and separation of some organic water pollutants
with unloaded and tri-n-octylamine loaded polyester-based polyurethane
foams; Talanta, 1994, 41, pp. 1481-1488.
263. R. Cassella, S. Garrigues, R.E. Santelli M. Guardia: Spectrophotometric
determination of carbaryl by on-line elution after its preconcentration onto
polyurethane foam; Talanta, 2000, 52, pp. 717-725.
264. L.J. Kice, F.Taymoorian: The reactivity of diphenylethylene and related olefins
toward free radicals evidence for Anomalous reactions of radicals from
diphenylethylene, J. Am. Chem. Soc 1959, 81, pp. 3405-3409.
265. K.W. Doak, D.L. Dineen: Copolymerization. XVI. The copolymerization of 2-
chlorobutadiene, 2, 3- dichlorobutadiene and 1,1- diphenylethylenes with
Olefins, J. Am. Chem. Soc 1951, 73, pp. 1084-1087.
266. T. Sato, N. Morita, M. Seno: Effect of 1,1 diphenylene on the radical
polymerization of di-n-butyl itaconate in benzene, Eur. Polym. J. 2001, 37, pp.
2055-2061.
267. K. Matyjaszewski: Controlled living radical polymerization. Washington, DC:
ACS; 1998, 31 (17), pp.5958-5959.
268. K. Matyjaszewski: Controlled living radical polymerization. Progress in ATRP,
NMP, and RAFT. Washington, DC: ACS: 2001, 78 (4), pp. 544.
269. K. Matyjaszewski: Advances in controlled/living radical polymerization. ACS
symposium series. Washington, DC: ACS; 2003, 854, pp18-20.
270. T. Fukuda: Kinetics of living radical polymerization, Prog. Polym. Sci. 2004,
29, pp. 329-385.
147
271. J. Qiu, B. Charleux, K. Matyjaszewski: Controlled/living radical polymerization
in aqueous media: homogeneous and heterogeneous systems, Prog. Polym.
Sci. 2001, 26, 10, pp. 2083-20134.
272. J.M. Asua: Miniemulsion Polymerization, Prog. Polym. Sci. 2002, 27(7),
pp.1283-12346.
273. PC. Wieland, B. Raether, O. Nuken: A new additive for controlled radical
polymerization, Macromol. Rapid Commun., 2001, 22, pp.700-703.
274. PC. Wieland, O. Nuken, M. Schäfer: Synthesis of new graft copolymers by
combining the DPE technique and cationic polymerization, Macromol. Rapid
Commun., 2002, 23, pp. 809-813.
275. PC. Wieland, O. Nuyken, M. Schmidt, K. Fischer: Amphiphilic graft
copolymers and hyperbranched polymers based on (3-vinylphenyl)
azomethylmalonodinitrile, Macromol. Rapid Commun., 2001, 22,pp. 1255-
1260.
276. B. Weber: Selbststrukturierende Hybridmaterialien für polymere Werkstoffe,
Duissertation; Universität Paderborn, 2009.
277. H. Zhaohua, L. Zhaoliag, H. Junlian: A novel kind of antitumour drugs using
sulphonamide as parent compound; European J. Medic. Chem., 2002, 36, pp.
863-872.
278. H.
:
Zhaohua,
Y.
Genjin, L.
Zhaoliag
,
H. Junlian:
2-(N1-2-
pyrimidylaminobenzene- sulfonamidol) ethyl 4- bis (2-chloroethyl) aminophenyl
butyrate: A potent antit- umor agent; Bioorganic & Medicinal Chemistry
Letters, 2001, 11, pp. 1099-1103.
279. T.B. Vree, A.J. Ven, C.P. Wissen, E.W. Kolmer, A.E. Swolfs, P.M. Galen, H.
Amatdjiais-Groenen: Isolation, identification and determination of sulfameth-
148
oxazole and its known metabolites in human plasma and urine by high-
performance liquid chromatography; J. of Chromatography B, 1994, 658, pp.
327-340.
280. S. Ghidini, E. Zanardi, G. Varisco, R. Chizzolini: Prevalence of molecules of
antibiotics in bovine milk in lombardia and emailia Romagna (Italy); Ann. Fac.
Medic. Vet. Di Parma, 2002, 22, pp. 245-255.
281. H. Oka, H. Nakazawa, K. Harada, J.D. MacNeil: Chemical analysis for
antibiotics in agriculture; AOAC International, Arlington, USA. 1995.
282. S. Bogialli, V. Capitolion, R. Di. Curini, A. Corcia, M. Nazzari, M. Sergi: Simple
and rapid liquid chromatography-tandem mass spectrometry confirmatory
assay for determining amoxicillin and ampicillin in bovine tissues and milk; J.
Agric. Food Chem., 2004, 52, pp. 3286-3291.
283. T. Christian, R.J. Schneider, H.A. Färber, D. Skultarek, M.T. Meyer, H.R.
Goldbach: Determination of antibiotic residues in manure, soil, and surface
waters, Acta Hydrochim. Hydrobiol, 2003, 31/1, pp. 36-44.
284. M. Grote, C. Schwake-Anduschus, H. Stevens, W. Heyser, G. Langenkämper,
T. Betsche M. Freitag: Incorporation of veterinary antibiotics into crops from
manured soil; Landbauforschung Voelkenrode 1, 2007, 57, pp. 25-32.
285. C.K. Fagerquist, A.R. Lightfied: Confirmatory analysis of antibiotics in kidney
tissue by liquid chromatography/electrospray ionisation selective reaction
monitoring ion trap tandem mass spectrometry; Rapid Commun. Mass
Spectrom., 2003, 17, pp. 660-671.
286. O. Corcoran, J.K. Nicholson, E.M. Lenz, F. Abou-Shakra, J. Castro-Perez,
A.B. Sage, I. D. Wilson: Directly coupled liquid chromatography with
inductively coupled plasma mass spectrometry and orthogonal acceleration
time-of-flight mass spectrometry for the identification of drug metabolites in
149
urine: application to diclofenac using chlorine and sulphur detection, Rapid
Commune Mass Spectrom. 2000, 14, pp. 2377-2384.
287. J. Trocewicz: Urine sample preparation of tricyclic antidepressants by means
of a supported liquid membrane technique for high-performance liquid
chromatographic analysis; J. of Chromatography. B, 2004, 801, pp. 213-220.
288. M. Lindsey, M. Meyer, E.M. Thurman: Analysis of trace levels of sulphonamide
and tetracycline antimicrobials in groundwater and surface water using solid-
phase extraction and liquid chromatography/mass spectrometry; Anal. Chem.,
2001, 73, pp. 4640-4646.
289. S. Castiglioni, R. Fanelli, D. Calamari, R. Bagnati, E. Zuccato: Methodological
approaches for studying pharmaceuticals in the environment by comparing
predicted and measured concentrations in river Po, italy; Regulatory
Toxicology and Pharmacology, 2004, 39, pp. 25-32.
290. R. Lindberg, P-A, Jarnheimer, B. Olsen, M. Johansson, M. Tysklind:
Determination of antibiotic substances in hospital sewage water using solid
phase extraction and liquid chromatography/mass spectrometry and group
analogue internal standards; Chemosphere, 2004, 57, pp.1479-1488.
291. M. Clara, B. Strenn, O. Gans, E.Martinez, N. Kreuzinger, H. Kroiss: Removal
of selected pharmaceuticals, fragrances and endocrine disrupting compounds
in a membrane bioreactor and conventional wastewater treatment plants;
Water Rese., 2005, 39, pp. 4797-4807.
292. A. Chow, W. Branagh, J. Chance: Sorption of organic dyes by polyurethane
foam; Talanta, 1990, 37, pp.407-412.
293. P.D. Dryan, K.R. Hawkins, J.T. Stewart, A.C. Capomacchia: Analysis of
chlortetracycline by high performance liquid chromatography with post column
150
alkaline-induced fluoresence detection; Biomed. Chromatogr. 1992, 6, pp.310-
350.
294. A.B. Farag, M.S. EL- Shahawi, S. Farrag: The sorption behaviour and
separation of some metal thiocyanyte complexes on polyether-based
polyurethane foam; Talanta, 1994, 4, pp. 671-623.
295. H. Stevens: Untersuchung zum Verhalten von Veterinärpharmaka im Boden,
Dissertation; Universität Paderborn, 2009.
296. M. Granados, M. Encabo, R. Compañó, M. Prat: Determination of tetracyclines
in water samples using liquid chromatography with fluorimetric detection;
Chromatographia, 2005, 61, pp. 471-477.
297. H. Lord, J.Pawliszyn: Microextraction of Drugs; Review, J. of Chromatography
A, 2000, 902, pp. 17-63.
