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Laser-induced fluorescence detection at 266 nm in capillary electrophoresis Polycyclic aromatic hydrocarbon metabolites in biota

Abstract

The authors wish to thank the Dutch Foundation for the Advancement of Science (NOW) for financial support and equipment (grant No. 344-006). Also, the technical assistance of Mr. J. Buijs is much appreciated.

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Laser-induced fluorescence detection at 266 nm in capillary electrophoresis Polycyclic aromatic hydrocarbon metabolites in biota

Author: Kuijt, J.,García Ruiz, Carmen,Stroomberg, G.J.,Marina Alegre, María Luisa,Ariese, Freek,Brinkman, U.A.Th.,Gooijer, Cees
Publisher: Elsevier
Year: 2001
DOI: 10.1016/S0021-9673(00)01040-2
Source: https://ebuah.uah.es/dspace/bitstream/10017/1352/1/PAHs-J%20Chromatogr%20A%2c%20907%2c%20291-299.pdf
Jou nal o Ch oma og aphy A, 907 (2001) 291–299 www.else ie .com/loca e/ch oma
Lase -induced luo escence de ec ion a 266 nm in capilla y
elec opho esis
Polycyclic a oma ic hyd oca bon me aboli es in bio a
ab cba
´
J. Kuij , C. Ga cıa-Ruiz , G.J. S oombe g , M.L. Ma ina , F. A iese ,
aa,
*
U.A.Th. B inkman , C. Gooije
a
V ije Uni e si ei
,
Depa men o Analy ical Chemis y and Applied Spec oscopy
,
De Boelelaan
1083, 1081
HV Ams e dam
,
The Ne he lands
b
´´´´
Uni e sidad de Alcala
,
Depa amen o de Quımica Analı ica
,
Facul ad de Quımica
,
C a
.
Mad id–Ba celona
,
Km
. 33,600,
´
E-
28871
Alcala de Hena es
,
Mad id
,
Spain
c
V ije Uni e si ei
,
Ins i u e o En i onmen al S udies
,
De Boelelaan
1115, 1081
HV Ams e dam
,
The Ne he lands
Recei ed 30 June 2000; ecei ed in e ised o m 29 Sep embe 2000; accep ed 13 Oc obe 2000
Abs ac
The sepa a ion o i e phenolic polycyclic a oma ic hyd oca bon me aboli es (hyd oxy-PAHs) has been pe o med by
cyclodex in-modi ied micella elec okine ic ch oma og aphy (CD-MEKC) using a 30 mMbo a e bu e (pH 9.0)
con aining 60 mMsodium dodecyl sul a e and a ying concen a ions o g-cyclodex in (g-CD). A concen a ion o 12.5
mMg-CD was ound o p o ide a baseline sepa a ion o he i e hyd oxy-PAHs. We applied con en ional luo escence and
lase -induced luo escence (LIF) de ec ion, using a new, small-size, quad upled Nd–YAG lase emi ing a 266 nm. The bes
limi s o de ec ion, in he low ng/ml ange, we e achie ed using LIF de ec ion. Fo all analy es, linea i y was obse ed up o
ca. 100 ng/ml. As an applica ion, conjuga ed py ene me aboli es in hepa opanc eas samples om he e es ial isopods
Oniscus asellus and Po cellio scabe we e sepa a ed and de ec ed. Finally, la ish bile samples om indi iduals exposed o
pollu ed sedimen o c ude oil, which we e pa o an in e labo a o y s udy, we e analyzed by CD-MEKC wi h con en ional
luo escence and LIF de ec ion o de e mine he 1-hyd oxypy ene concen a ions. 2001 Else ie Science B.V. All igh s
ese ed.
Keywo ds
:
Lase -induced luo escence de ec ion; De ec ion, elec opho esis; Fish; Polynuclea a oma ic hyd oca bons
1. In oduc ion elec opho esis (CE), mainly because LIF de ec ion
using exci a ion in he deep UV ange is no s aigh -
A p esen , lase -induced luo escence (LIF) de- o wa d. Un il now, such exci a ion equi ed he use
ec ion o analy es exhibi ing na i e luo escence, o la ge ame a gon ion lase s o excime lase -
ollowing exci a ion in he deep UV ange, has been pumped dye lase sys ems [1,2]. Un o una ely, hese
ha dly exploi ed o de ec ion pu poses in capilla y lase sys ems a e expensi e and imp ac ical in
analy ical applica ions because o hei la ge dimen-
sions.
*Co esponding au ho . Fax: 131-20-4447-543.
E-mail add ess
:
[email p o ec ed] (C. Gooije ). In his s udy, he pe o mance in LIF de ec ion o
0021-9673/01/$ – see on ma e 2001 Else ie Science B.V. All igh s ese ed.
PII: S0021-9673(00)01040-2
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a new, small-size, quad upled Nd–YAG lase emi - was used o p epa e bu e s and analy e s anda d
ing 266-nm adia ion a a high pulse equency was solu ions. Bu e s we e adjus ed o he equi ed pH
in es iga ed. Such a lase sys em will be o special using 1 MNaOH. Bo ic acid and asco bic acid we e
in e es in bioanaly ical s udies since he 266-nm ob ained om J.T. Bake (De en e , The Ne he -
ou pu is ully compa ible wi h he exci a ion o lands), absolu e e hanol (analy ical- eagen g ade)
¨
na i ely- luo escen amino acids ( y osine, om Riedel-de Haen (Seelze, Ge many) and sodium
yp ophan and phenylalanine). In he p esen s udy, dodecyl sul a e (SDS) om Fluka (Buchs, Swi ze -
howe e , i s app op ia eness o de ec ion o polynu- land). 1,5-Naph halenedisul onic acid and g-cyclo-
clea a oma ic hyd oca bon (PAH) me aboli es is dex in hyd a e we e pu chased om Ald ich (S .
es ed. Louis, MO, USA). b-Glucu onidase/a yl sul a ase
Because he me abolism o PAHs a e PAH ( om Helix poma ia, EC 3.2.1.31 and EC 3.1.6.1, 30
exposu e is e y as o mos o ganisms, he con- and 60 U/ml, espec i ely) was ob ained om
cen a ions o PAH me aboli es in bio ic ma ices a e Me ck (Da ms ad , Ge many). Bu e solu ions we e
gene ally much highe han hose o he pa en il e ed o e 0.45-mm sy inge il e s (Schleiche &
PAHs. I is he e o e ad an ageous o ocus a en ion Schuell, Dassel, Ge many) be o e use.
on he de e mina ion o PAH me aboli es, ins ead o
on hei pa en s. In he las decade he quan i ica ion
2.2.
S anda d solu ions and samples
o PAH me aboli es in exc e a (u ine, bile and eces)
has become an impo an me hod o he biomoni o - The hyd oxy-PAHs used in his s udy a e 1-hy-
ing o PAH exposu e in a ious e es ial and d oxypy ene, 3-hyd oxybenzo[a]py ene, 1-hyd oxy-
aqueous ecosys ems [3–7], as well as o moni o ing phenan h ene, 1-hyd oxych ysene and 2-hyd oxy-
human PAH exposu e [8–13]. naph halene. S ock solu ions con aining hese i e
Speci ically, 1-hyd oxypy ene has ex ensi ely hyd oxy-PAHs (10 mg/ml) as well as he ish bile
been used as a bioma ke o PAH exposu e. The samples we e dis ibu ed as pa o a Eu opean
de e mina ion o 1-hyd oxypy ene and o he hy- Union (EU)- unded in e labo a o y s udy (SMT 4-
d oxy-PAHs is pe o med a e enzyma ic hyd olysis CT 98-2250) [17]. The s ock solu ions had been
o phase II conjuga es such as 1-hyd oxypy ene p epa ed wi h e hanol–wa e (80:20, / ), con aining
sul a e and 1-hyd oxypy ene glucu onide. Al hough 5 mg/ml asco bic acid o a oid oxida ion. F om he
s anda ds a e no ye comme cially a ailable, he s ock solu ions, 1 mg/ml solu ions we e p epa ed
po en ial o di ec moni o ing o phase II me aboli es using e hanol–wa e (80:20, / ) wi h 5 mg/ml
has also been explo ed [5,9,10,13]. asco bic acid. In o de o p epa e calib an solu ions,
Phenolic and conjuga ed PAH me aboli es a e u he dilu ions we e made by mixing wi h e hanol–
usually analyzed by liquid ch oma og aphy (LC) wa e (80:20, / ) wi hou asco bic acid.
combined wi h luo escence de ec ion [3–13]. Few Hepa opanc eas samples om he isopods Po cel-
s udies epo on he sepa a ion o hyd oxy-PAHs by lio scabe and Oniscus asellus, which con ained
CE [14–16], bu un il now CE has no been applied conjuga ed py ene me aboli es, we e ob ained as
o he de ec ion o hese compounds in eal (bio ic) desc ibed by S oombe g e al. [5]. B ie ly, he
samples. In he p esen s udy he sepa a ion and isopods we e s a ed o 3 days and indi idually
de ec ion o i e hyd oxy-PAHs, and o py ene and placed in scin illa ion ials o 48 h, oge he wi h
i s me aboli es, in biological ma ices ( ish bile and 100 mg o g ound lea es spiked wi h py ene a a
isopod hepa opanc eas) is s udied. le el o 10% (w/w) d y mass. A e dissec ion,
hepa opanc eases o 10 animals we e pooled in 100
ml o T is bu e (pH 9.0) and 20 ml o p o ease K
2. Ma e ials and me hods was added. P o eolysis was pe o med o 18 h a
378C. Nex , an equal olume o e hanol was added
2.1.
Chemicals and ma e ials and he emaining deb is was p ecipi a ed by 3-min
cen i uga ion a 5000 pm. Indi idual me aboli e
Wa e demine alized and dis illed in he labo a o y solu ions we e ob ained by ac iona ion o he
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samples by means o e e sed-phase LC, wi h a Meylan, F ance), emi ing a 266 nm wi h an a e age
g adien o ace oni ile and ammonium ace a e bu e ou pu powe o 5.4 mW, a pulse wid h o 0.34 ns
(10 mM, pH 5.0) [5]. Fo p olonged use, all s an- and a epe i ion a e as high as 7.8 kHz, was ocused
da ds and samples we e s o ed in he e ige a o a in o he liquid co e o he capilla y by a qua z lens
2208C. Be o e use, he solu ions we e sonica ed o wi h a ocal dis ance o 3 cm. A 253, N.A. 0.4
5 min. e lec i e objec i e (Ealing, Hollis on, MA, USA)
was used o collec he luo escence emission. The
2.3.
Ins umen al se -up 9558 QA pho omul iplie ube (EMI, Middlesex,
UK) used o de ec ion was connec ed o a 456H
An LS-50B luo escence spec ome e (Pe kin- powe supply (O ec, B acknell, UK) ope a ed a
Elme , Beacons ield, UK) was used o eco d luo- 1000 V. Neu al densi y il e s we e used in o de o
escence exci a ion and emission spec a. Elec- dec ease he i adiance o he capilla y de ec ion
ophe og ams we e ob ained using a P ince high- window. A UG-1 bandpass il e and BG-14 o
ol age/injec ion sys em (Laue labs, Emmen, The GG-13 cu -o il e s (Scho , Mainz, Ge many) we e
Ne he lands) in combina ion wi h a con en ional FP- used o collec all emission and disc imina e agains
920 luo escence de ec o (Jasco, Tokyo, Japan) o a sca e ed exci a ion ligh .
labo a o y-buil se -up o LIF de ec ion. CE sepa-
a ions using he con en ional luo escence de ec o
we e pe o med a a ol age o 20 kV wi h a 90 3. Resul s and discussion
cm375 mm I.D. uncoa ed used-silica capilla y
(BGB Analy ik, Anwil, Swi ze land) wi h an e ec- This sec ion i s discusses he CE sepa a ion and
i e leng h o 60.5 cm. Fo he LIF expe imen s a luo escence de ec ion o i e hyd oxy-PAHs which
104 cm capilla y wi h an iden ical e ec i e leng h would be he a ge analy es in he ish bile samples.
was used; he sepa a ion was un a 23.3 kV o The pa en PAHs a e usually no obse ed in such
main ain he same ield s eng h (221 V/cm). The samples. The e o e, i is no necessa y o in ol e he
injec ion p essu e was 25 mba and he injec ion ime pa en compounds in he sepa a ion. Emphasis is on
0.1 min. Fo da a collec ion a compu e equipped he pe o mances o he new 266-nm LIF me hod
wi h CLASS-VP da a-acquisi ion so wa e was used. compa ed wi h con en ional luo escence de ec ion.
The LIF se -up is shown in Fig. 1. The ligh om Subsequen ly, he de e mina ion o py ene me abo-
a quad upled Nd–YAG NanoUV lase (Uniphase, li es in isopods and ish bile samples will be dis-
cussed. Fo such complex ma ices he LIF me hod
will, no doub , su e om he disad an age ha i
o e s no selec i i y in exci a ion se ings: only one,
single, wa eleng h is a ailable, i.e., 266 nm. Com-
pa ison wi h con en ional luo escence de ec ion is,
he e o e, o dis inc in e es .
3.1.
CE o hyd oxy-PAHs
To pe o m con en ional luo escence de ec ion
unde op imum condi ions, he exci a ion and emis-
sion luo escence spec a o he hyd oxy-PAHs we e
eco ded in he selec ed bu e sys em (see below). I
mo e han one maximum was p esen , as is he case
o he exci a ion spec a, he maximum gi ing he
Fig. 1. De ec ion sys em o LIF de ec ion. UVL: 266-nm lase ; highes signal- o-noise a io (S/N) in he elec-
F1: neu al densi y il e ; L: ocusing lens; C: capilla y ( ocusing ophe og ams was chosen. The maxima used o
poin ); O: e lec ing objec i e; M: mi o ; F2: bandpass o cu -o
il e ; PMT: pho omul iplie ube. de ec ion in CE a e gi en in Table 1. The con en-
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Table 1
a
Limi s o de ec ion (ng/ml) o i e hyd oxy-PAHs using CE wi h LIF and con en ional luo escence (CF) de ec ion
Compound CF LIF, UG-1 LIF, BG-14
3-Hyd oxybenzo[a]py ene 2 (383/435) 25 2
2-Hyd oxynaph halene 40 (275/344) 3 4
1-Hyd oxyphenan h ene 7 (306/361) 3 2
1-Hyd oxych ysene 35 (307/370) 10 6
1-Hyd oxypy ene 1 (347/387) 4 2
a
In pa en heses (CF): exci a ion/emission wa eleng hs used o de ec ion.
ional luo escence de ec o has a ixed exci a ion sli jec ions close o he de ec ion limi . As shown in
o 10 nm, bu he emission sli can be a ied (10, 18 Table 1, he LODs we e in he low ng/ml ange o
o 40 nm bandwid h). An emission bandwid h o 40 h ee o he es analy es, bu abou 10- old highe
nm ga e he bes esul s in e ms o S/N. o 2-hyd oxynaph halene and 1-hyd oxych ysene.
As a as he CE sepa a ion is conce ned, micella Using peak a eas, linea anges om 10 o 500
elec okine ic ch oma og aphy (MEKC) as such does ng/ml we e ob ained o 3-hyd oxybenzo[a]py ene
2
no su ice: using a 30 mMbo a e, 60 mMSDS and 1-hyd oxypy ene (wi h R alues o 0.9997 and
bu e (pH 9.0), all analy es we e ound o mig a e 0.9993, espec i ely; i e da a poin s in duplica e o
simul aneously. This is no su p ising because all bo h). Fo peak heigh s, linea i y was obse ed om
2
a ge compounds a e a he hyd ophobic and he e- 10 o 100 ng/ml wi h R alues o 0.9992 and
o e ha e simila a ini y o he micelles [18]. In 0.9969 ( ou da a poin s in duplica e) o 3-hyd oxy-
o de o gene a e selec i i y, g-cyclodex in (g-CD) benzo[a]py ene and 1-hyd oxypy ene, espec i ely.
was added o he bu e , an app oach p o en o be Fo 1-hyd oxyphenan h ene, linea i y was obse ed
aluable in he sepa a ion o a di e en se o om 25 o 200 ng/ml, using ei he peak a eas o
2
hyd oxy-PAHs [14]. The selec i i y ha can be peak heigh s (R50.9940; ou da a poin s in dupli-
2
achie ed wi h a g-CD–SDS bu e sys em is based ca e, and R50.9952; i e da a poin s in duplica e,
on he di e en pa i ioning o he analy es be ween espec i ely). Because he LODs o 2-hyd oxy-
he micella , aqueous and g-CD phases. The a ini y naph halene and 1-hyd oxych ysene we e a he
o a pa icula analy e o a CD molecule s ongly high, no linea anges we e de e mined o hese
depends on i s i in he CD ca i y. Al hough b-CDs compounds.
a e gene ally conside ed o be mo e e icien com- In gene al, he linea anges a e sho e when
plexing agen s han g-CDs, he la e a e p e e ed in using peak heigh s, which can be eadily explained
CD-MEKC because he b-CD molecules a e no able by he peak b oadening occu ing a le els abo e ca.
o bind analy es s ongly in micella bu e sys ems. 100 ng/ml. This peak b oadening is p esumably
I has been sugges ed ha his can be asc ibed o he caused by o e loading o he micella and g-CD
co-inclusion o indi idual SDS molecules which phases. The co-inclusion o indi idual SDS mole-
educes he ac ual ca i y size, especially in he case cules in o CD ca i ies, as men ioned abo e, implies
o b-CDs [19,20]. ha he e ec i e micella concen a ions a e lowe
In his wo k we used a 30 mMbo a e, 60 mM han expec ed om he o al SDS concen a ion and
SDS, pH 9.0 bu e wi h a ying concen a ions o he c i ical micella concen a ion. Also, he con-
g-CD (10, 12.5, 15 and 20 mM) o achie e he cen a ion o g-CD molecules wi h a ca i y la ge
sepa a ion o he i e hyd oxy-PAHs. A concen- enough o s ong inclusion o hyd oxy-PAHs will be
a ion o 12.5 mMwas ound adequa e o sepa a e educed. These assump ions a e suppo ed by he
all hyd oxy-PAHs. obse a ion ha he peak o 3-hyd oxy-
The limi s o de ec ion (LODs) o he hyd oxy- benzo[a]py ene, which shows he highes a ini y o
PAHs ob ained wi h con en ional luo escence de- he g-CD molecules, shows ailing a high con-
ec ion we e de e mined om h ee eplica e in- cen a ions, which indica es o e loading o he g-CD
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phase. On he o he hand, he on ing obse ed o il e wi h a ansmission (T) o 6.3%, he capilla ies
he 1-hyd oxypy ene peak a highe concen a ions could be used o a leas se e al weeks, while
sugges s o e loading o he micella phase. main aining adequa e de ec ion sensi i i y. A ypical
Wi h he con en ional luo escence de ec o op- LIF-de ec ed elec ophe og am o a s anda d mix u e
imum de ec ion sensi i i y o all compounds e- o he i e hyd oxy-PAHs is shown in Fig. 2. High
qui es p og ammed adjus men o he exci a ion and e iciency peaks we e ob ained wi h pla e numbe s o
emission wa eleng hs. This p o ed o be qui e 128 000, 199 000, 241 000, 191 000 and 214 000
di icul , because he mig a ion imes we e ound o (peak numbe s 2–6, espec i ely).
show sligh un- o- un a ia ions and he compounds The luo escence exci a ion spec a (no shown) o
a e mig a ing closely oge he . Mo eo e , he LODs he hyd oxy-PAHs sugges ha only 2-hyd oxy-
o 2-hyd oxynaph halene and 1-hyd oxych ysene naph halene and 1-hyd oxypy ene can be exci ed
will o en be inadequa e o he de e mina ion o e icien ly a 266 nm. Fo he o he me aboli es he
hese compounds in eal samples. The e o e, i is ex inc ion coe icien s a 266 nm a e a he low.
ce ainly wo hwhile o explo e he possibili ies o In e es ingly, hese di e ences a e no e lec ed in
LIF de ec ion. he LIF esul s: LODs in he low ng/ml ange we e
The LIF se -up (Fig. 1) was op imized unde achie ed o all compounds s udied (Table 1).
low-d i en condi ions (p essu e5100 mba ), using a P obably, measu emen s we e pe o med unde sa u-
26
solu ion o 5?10 M1,5-naph halenedisul onic acid. a ion condi ions: despi e he low mola abso p-
The backg ound le el was checked a e e e y i i ies a 266 nm, maximum exci a ion is eached
adjus men o a oid collec ion o s ay ligh om he due o he high peak powe . When using he BG-14
capilla y co e and wall. This was done by adjus ing cu -o il e , he LODs o 1-hyd oxypy ene and
he p essu e o ze o: hen, in he absence o low, he 3-hyd oxybenzo[a]py ene we e be e han wi h he
luo escence signal almos ins an aneously collapses UG-1 bandpass il e because he UG-1 il e , while
due o pho odecomposi ion. con enien ly excluding ambien ligh , is ha dly ans-
Fi s ly, he capilla y holde posi ion was op imized pa en abo e 400 nm. Compa ed wi h he esul s
so ha he ocal poin on he capilla y was exac ly in ob ained wi h con en ional luo escence de ec ion,
he cen e o he e lec i e objec i e. Then, he he LODs we e signi ican ly be e o 2-hyd oxy-
ocusing in o he capilla y liquid co e was op imized naph halene and 1-hyd oxych ysene.
by adjus ing he posi ion o he ocusing lens.
Subsequen ly, he dis ance o he e lec i e objec i e
o he illumina ed poin o he capilla y was op i-
mized o achie e op imum luo escence collec ion
and sca e ed ligh ejec ion. Finally, he posi ion and
angles o he mi o p ojec ing he luo escence
image on he pho omul iplie ube we e a ied o
op imum luo escence in ensi y. P ope alignmen o
he LIF se -up could easily be main ained o e
se e al mon hs, wi hou any e-alignmen . Also,
excellen long- e m ou pu powe s abili y was ob-
se ed, as was appa en om he s able and la
baselines ob ained.
I should be ealized ha he peak powe o he
lase used he e is s ill as high as 1.8 kW, despi e i s
modes a e age powe o 5.4 mW. I was obse ed Fig. 2. Elec ophe og am o a mix u e o i e hyd oxy-PAHs (20
ha such a high peak powe damages he capilla y ng/ml) using 266-nm LIF de ec ion. Emission il e : BG-14. O he
wi hin a ew hou s. Also, ai bubbles we e o med condi ions: see ex . EOF: elec oosmo ic low; 15asco bic acid;
wi hin he capilla y, p obably due o hea ing o he 253-hyd oxybenzo[a]py ene; 352-hyd oxynaph halene; 451-hy-
bu e . Fo una ely, when using a neu al densi y d oxyphenan h ene; 551-hyd oxych ysene; 651-hyd oxypy ene.

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To summa ize his sec ion on s anda d solu ions, i
can be concluded ha he 266-nm LIF de ec ion
me hod in es iga ed he e is gene ally applicable o
analy es exhibi ing na i e luo escence, despi e he
ixed exci a ion wa eleng h. The de ec ion limi s a e
sligh ly be e han hose ob ained wi h con en ional
luo escence de ec ion. A quan i a i e compa ison
wi h o he LIF de ec ion me hods is di icul o make
since di e ences in de ec ion con igu a ion play a
ole. In an MEKC sepa a ion o hyd oxy-PAHs,
Smi h e al. [14] achie ed LODs in he 0.08–3 mM
ange, alues dis inc ly less a o able han he da a
in Table 1. Howe e , hey used a capilla y wi h an
inne diame e o 50 mm and made use o ibe
op ics. In gene al i can be s a ed ha con inuous Fig. 3. Elec ophe og ams o py ene me aboli es isola ed om he
wa e a gon ion lase s pe o m be e in e ms o hepa opanc eas o (a) Oniscus asellus and (b) Po cellio scabe
achie able de ec ion limi s. In p elimina y expe i- using 266-nm LIF de ec ion. Emission il e : BG-14. Bu e : 30
men s on naph halene sul ona es, using 266-nm LIF mMbo a e, 60 mMSDS, 10 mMg-CD, pH 9.0. 151-Hyd oxy-
py ene sul a e; 25unknown py ene me aboli e; 351-hyd oxy-
de ec ion, LODs in he low nM ange we e ob ained py ene; 45py ene; 551-hyd oxypy ene glucoside.
[21], which is abou one o de o magni ude highe
han ob ainable using exci a ion by a con inuous
wa e a gon ion lase [1,2]. Such a di e ence in men ioned abo e, eco ded wi h LIF de ec ion using
pe o mance should be expec ed in iew o he he BG-14 cu -o il e , a e shown in Fig. 3.
pulsed na u e o he p esen lase (du y cycle: 3?Theo e ical pla e numbe s a e ypically 241 000,
26
10 ). 93 000, 137 000, 97 000 and 91 000 o peak num-
be s 1–5. The conjuga ed PAH me aboli es could be
3.2.
Py ene me aboli es in isopods well sepa a ed by CE using a 30 mMbo a e, 60 mM
SDS, 10 mMg-CD, pH 9.0 bu e . Howe e , py ene
In a p e ious s udy i was concluded ha he and 1-hyd oxypy ene glucoside showed pa ial o e -
py ene me aboli e concen a ions in isopods, spe- lap (R: 0.40) wi h his bu e composi ion. Thei
s
ci ically, Oniscus asellus and Po cellio scabe , can esolu ion equi ed 12.5 mMg-CD in he bu e .
be used as a bioma ke o PAH exposu e in he Un o una ely, unde hese condi ions he 1-hyd oxy-
e es ial en i onmen [5]. Moni o ing he conju- py ene sul a e peak o e lapped wi h a compound
ga ed py ene me aboli es di ec ly, ins ead o 1-hy- p esen in he sample ma ix. Ne e heless, when
d oxypy ene a e enzyma ic hyd olysis, can be using bo h bu e s sys ems all a ge analy es can be
ad an ageous because he analy e de ec abili y is moni o ed.
3–5- imes highe in ha case [9,10,13]. Mo eo e ,
de ec ion o he conjuga ed PAH me aboli es ins ead
3.3. 1
-Hyd oxypy ene in ish bile
o he hyd oxy-PAHs can gi e impo an in o ma ion
ega ding phase II me abolic pa hways. He e, he As a second applica ion, wo ish bile samples
applicabili y o CE–LIF was es ed o he de ec ion we e analyzed, bile om plaice (Pleu onec es pla es-
o py ene, 1-hyd oxypy ene and he h ee conjuga ed sa) exposed o c ude oil, and om lounde (Pla ich-
py ene me aboli es, 1-hyd oxypy ene sul a e, 1-hy- hys lesus) exposed o con amina ed sedimen . These
d oxypy ene glucoside and an unknown phase II samples had been dis ibu ed as pa o an in e -
py ene me aboli e. Since he conjuga es a e no labo a o y s udy [17]. The me hods used in his s udy
comme cially a ailable, quan i ica ion was no pos- by o he labo a o ies we e LC wi h con en ional
sible. luo escence de ec ion and gas ch oma og aphy–
Elec ophe og ams o he wo isopod samples mass spec ome y (GC–MS).
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297
In his applica ion he quan i a i e aspec s o CE
wi h con en ional luo escence and LIF de ec ion,
we e es ed, he a ge analy e being 1-hyd oxy-
py ene. In iew o he da a assembled in Table 1, o
his pa icula me aboli e con en ional luo escence
de ec ion will p obably be he me hod o choice:
compa ed o 266-nm LIF i pe o ms equally in
e ms o LODs bu i p o ides addi ional exci a ion
selec i i y. The ish bile samples (50 ml) we e
weighed and hyd olysed enzyma ically o 2 h a
378C a e he addi ion o 20 ml o enzyme (b-
glucu onidase/a yl sul a ase) and 180 ml o wa e .
A e incuba ion, 1000 ml o absolu e e hanol was
added and he sample was cen i uged o 5 min a
7000 pm; nex , he supe na an was aken o
analysis.
As was al eady indica ed abo e, i was no su p is-
ing ha analyzing he ish bile samples by CE wi h
266-nm LIF de ec ion and using he BG-14 cu -o
il e , ga e ise o a la ge numbe o peaks in he
elec ophe og ams, especially wi h he oil-exposed Fig. 4. Elec ophe og ams o ish bile samples a e enzyma ic
hyd olysis using 266-nm LIF de ec ion. Emission il e : GG-13.
ish bile. The in e e ing peaks inhibi ed eliable O he condi ions: see ex . (a) Oil-exposed plaice bile, (b) sedi-
ecogni ion o mos o he hyd oxy-PAHs discussed men -exposed lounde bile. The 1-hyd oxypy ene peaks a e
in Sec ion 3.1 by means o spiking. Only 1-hyd oxy- indica ed by a ows.
py ene, which was ound o be p esen a a much
highe concen a ion han he o he hyd oxy-PAHs,
could be unambiguously iden i ied. In o de o sen ed in Table 2. I is in e es ing o compa e he
imp o e he selec i i y o LIF de ec ion, a GG-13 esul s wi h hose ob ained in he in e labo a o y
cu -o il e , which emo es all adia ion below ca. s udy [17]. Fo he sedimen -exposed lounde bile
395 nm, was used ins ead. This caused a subs an ial he concen a ions as de e mined independen ly by
educ ion o he numbe o peaks o he sedimen - se en labo a o ies we e ound o be in he 3.061.9
exposed ish bile, bu no o he oil-exposed ish bile mg/g ange (n57, 95% con idence in e al), while
(Fig. 4). o he oil-exposed plaice bile he ange was 1.260.4
I was expec ed ha he use o con en ional (n56). The esul s p esen ed in Table 2 a e ully in
luo escence de ec ion would u he imp o e he line wi h hese da a. The small di e ences be ween
selec i i y, since he exci a ion and emission maxima he LIF and CF da a migh be sys ema ic, bu he
o 1-hyd oxypy ene a e a a he high wa eleng hs ange o 1-hyd oxypy ene concen a ions de e mined
(c . Table 1). Indeed, he elec ophe og ams now by he o he labo a o ies is o b oad o a de ini e
became much cleane (Fig. 5), wi h he elec- conclusion.
ophe og am o he lounde bile exhibi ing only one
la ge peak.
Quan i ica ion was pe o med by using he ex e - 4. Conclusions
nal s anda d me hod wi h calib a ion cu es in he
ange om 16 o 100 ng/ml ( ou da a poin s in Compa ed o o he a ailable deep UV lase sys-
iplica e). Be o e injec ion he oil- and sedimen - ems he quad upled Nd–YAG lase used in his
exposed ish bile samples we e dilu ed wi h e hanol– s udy has se e al ad an ages. I is compac , inexpen-
wa e (80:20, / ) o gi e a o al dilu ion o 503si e and ugged (expec ed ope a ing li e ime: 10 000
and 1003, espec i ely. Rele an esul s a e p e- h). Nex , he alignmen o he LIF se -up is easily
298 J
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907 (2001) 291
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il e is used o educe he inciden powe . The las
cha ac e is ic implies ha he 266-nm CE–LIF de ec-
o can be gene ally used o analy es exhibi ing
na i e luo escence; e en when he mola abso p-
i i y a 266 nm is poo . This is illus a ed by he
LODs ob ained o he i e hyd oxy-PAHs s udied:
simila LODs (2–6 ng/ml) a e ob ained o all o
hem al hough h ee o hem ha e low abso p i i ies
a 266 nm.
O cou se, i eal samples ha e o be analyzed, he
inhe en lack in exci a ion selec i i y can be dis-
ad an ageous. This is clea ly illus a ed by he
elec ophe og ams o he oil-exposed ish bile.
Ne e heless, he 1-hyd oxypy ene concen a ions
de e mined in bo h bile samples using 266-nm LIF
de ec ion a e compa able o hose ob ained wi h
con en ional luo escence, and wi hin he ange o
concen a ions ound by o he labo a o ies using LC–
luo escence de ec ion.
Fig. 5. Elec ophe og ams o ish bile samples a e enzyma ic Finally, i is expec ed ha 266-nm LIF will ha e
hyd olysis using con en ional luo escence moni o ing wi h
l
ex
pe spec i e o de ec ion in CE, especially when
347 nm and
l
387 nm. O he condi ions: see ex . (a) Oil-
em
a en ion is ocused on molecules like y osine,
exposed plaice bile, (b) sedimen -exposed lounde bile. The yp ophan and phenylalanine, because he 266-nm
1-hyd oxypy ene peaks a e indica ed by a ows. lase line is close o he luo escence exci a ion
maxima o hese amino acids.
main ained o e se e al mon hs and he lase shows
excellen long- e m ou pu powe s abili y p o iding
s able baselines and eliable de ec ion. Finally, i s
ou pu powe is high enough o sa u a e he abso p- Acknowledgemen s
ion ansi ions e en when a 6.3% Tneu al densi y
The au ho s wish o hank he Du ch Founda ion
Table 2 o he Ad ancemen o Science (NOW) o inancial
1-Hyd oxypy ene concen a ions in PAH-exposed ish bile and suppo and equipmen (g an No. 344-006). Also,
calib a ion plo cha ac e is ics, using CE wi h LIF and con en ion-
a
he echnical assis ance o M . J. Buijs is much
al luo escence (CF) de ec ion app ecia ed.
Concen a ion 1-hyd oxy-
py ene (mg/g)
LIF CF
Plaice bile (oil-exposed) 1.8 (0.07) 1.5 (0.04) Re e ences
1.7 (n51) 1.3 (n52)
[1] S.J. Kok, I.C.K. Isbe g, C. Gooije , U.A.Th. B inkman, N.H.
Flounde bile (sedimen -exposed) 4.5 (0.07) 4.0 (0.28) Vel ho s , Anal. Chim. Ac a 360 (1998) 109.
4.1 (n52) 3.8 (n52) [2] S.J. Kok, G.P. Hoo nweg, T. de Ridde , U.A.Th. B inkman,
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2b
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a
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