Colorimetric detection and determination of Fe(III), Co(II), Cu(II) and Sn(II) in aqueous media by acrylic polymers with pendant terpyridine motifs

Accep edmanusc ip.Publishedmanusc iplink: h p://www.sciencedi ec .com/science/a icle/pii/S0925400515306948 doi:10.1016/j.snb.2015.11.116  Colo ime ic de ec ion and de e mina ion o Fe(III), Co(II), Cu(II) and Sn(II) in aqueous media by ac ylic polyme s wi h pendan e py idine mo i s Mi iam T igo-López, Asunción Muñoz, Sa u nino Ibeas, Felipe Se na, Félix Clemen e Ga cía and José Miguel Ga cía* Depa amen o de Química, Facul ad de Ciencias, Uni e sidad de Bu gos, Plaza de Misael Bañuelos s/n, 09001 Bu gos, Spain. Fax: (+) 34 947 258 831, Tel: (+) 34 947 258 085. E-mail: [email p o ec ed] G aphical abs ac ABSTRACT Colo ime ic ca ion esponsi e wa e soluble polyme s and manageable ilms o memb anes ha e been designed. The senso y ma e ials espond wi h a colou change o he p esence in wa e o Fe(III), Co(II), Cu(II), and Sn(II). The colou change is speci ic o each me al ca ion, and enables i s iden i ica ion (pu ple o i on, o ange o cobal , g een o coppe , and yellow o in). The design o he ma e ials elies on an addi ion monome ha ing a e py idine moie y, which beha es as a dye in p esence o ansi ion me al ca ions due o i s p o en chela ing capabili y owa d hese species and he colou de elopmen ha always accompany he me allic complex o ma ion. Wa e solu ions o he senso y linea polyme s allow o he UV/ is i a ion o Fe(III), Co(II), Cu(II), 1 Accep edmanusc ip.Publishedmanusc iplink: h p://www.sciencedi ec .com/science/a icle/pii/S0925400515306948 doi:10.1016/j.snb.2015.11.116 2 and Sn(II) wi h a limi o de ec ion o 1.3x10-7, 6.4x10-8, 1.3x10-5 and 1.4x10-5 M, espec i ely. On he o he hand, senso y ki s, cu om senso y memb anes, pe mi ed he isual quan i ica ion o he ca ions in a dynamic ange o i e decades (1x10-7 - 5x10-3 M) o Fe(III) and Co(II) and o wo decades (9x10-5 - 9x10-3 M) o Cu(II) and Sn(II). Ti a ion cu es can also be d awn om a pic u e aken o he senso y ki s wi h a sma phone, by using he digi al colou de ini ion o he ma e ials as analy ical signal. Also, a e en e ing in o con ac wi h hands, shapes o me allic objec s (i on and cobal con aining ools) can be colou e ealed by p essing he hands on pape o co on ab ics we ed wi h wa e solu ions o he linea senso y polyme . Keywo ds Senso y polyme s, e py idine, ca ion de ec ion, o ensic applica ions 1. INTRODUCTION The cos less, in-si u, and as de ec ion and quan i ica ion o ansi ion me al ca ions in pu e wa e a e o he u mos en i onmen al, indus ial, and heal h impo ance. T adi ional echniques, such as a omic abso p ion spec oscopy (AAS) o induc i ely coupled plasma mass spec ome y (ICP-MS), enable he selec i e and p ecise de ec ion and quan i ica ion o he men ioned chemical species. Howe e , hey a e hea y, bulky, ex emely expensi e echniques and equi e ained pe sonnel. On he o he hand, chemical senso s ha e become a simple species de ec ion me hod o non- ained pe sonnel, especially i he ansduc ion is ch omogenic (i.e., by a colou change) and he de ec ion can be ca ied ou isually. Chemical senso s a e an eme ging echnology wi h expanding applicabili y o a numbe o ields, such as ci il secu i y, en i onmen al con ol and emedia ion, medicine, and indus ial con ol. Mo eo e , senso y polyme s, which a e Accep edmanusc ip.Publishedmanusc iplink: h p://www.sciencedi ec .com/science/a icle/pii/S0925400515306948 doi:10.1016/j.snb.2015.11.116 3 mac omolecules ha ha e ecep o mo i s (o binding si es) in hei s uc u e, ep esen a s ep u he and show signi ican ad ances o e disc e e (o low molecula mass) chemosenso s. Thus, polyme s can be p epa ed o ans o med in o ilms, coa ings o inished senso y ma e ials wi h di e en shapes. Dis inc polyme geome ies a e achie able (linea , sphe ical, and idimensional c osslinked ne wo k). They can be easily designed o wo k in hyd ophobic o hyd ophilic en i onmen s and can be used o sense bo h apou s and liquids. Also, hey exhibi collec i e p ope ies sensi i e o mino pe u ba ions. Finally, hei senso y moie ies canno mig a e wi h he concomi an inc ease in he pe o mance s abili y along ime, imp o e in he he mal and chemical esis ance, and can be easily eused. Chemosenso y polyme s ollowing a esea ch me hodology based on a gua an eed o success s a egy ha e been p epa ed. Tha is o say, once chemical species o be de ec ed a e selec ed, he so-called a ge s, ully con iden ecep o s o such a ge s a e looked in scien i ic li e a u e o ind, usually, disc e e o ganic molecules ha a e insoluble in wa e ; hen, hei chemical s uc u e is sligh ly modi ied by including a polyme izable g oup; and inally i is copolyme ized wi h comme cial hyd ophilic and hyd ophobic monome s o ha e wa e soluble linea polyme s and c osslinked memb anes wi h gel s uc u es ha allow o he de ec ion in 100% wa e . The a ge species o his wo k a e ansi ion me al ca ions (Fe(III), Co(II), Cu(II) and Sn(II)), and he ecep o co e is based on a e py idine (2,2’:6’,2’’- e py idine, py) mo i . Mo gan and Bu s al isola ed py and desc ibed i s pu ple complex wi h i on(II) in he 1930s [1]. Since hen py has become one o he mos used ligands wi h mul iple applica ions in di e en esea ch and echnological a eas, such as coo dina ion polyme s [2-4]; senso s o anion [5-8], ca ions [9-17], bo h[18,19], and biomolecules Accep edmanusc ip.Publishedmanusc iplink: h p://www.sciencedi ec .com/science/a icle/pii/S0925400515306948 doi:10.1016/j.snb.2015.11.116 4 [20,21]; gela ion and sol och omic senso s [22]; luminescen con e e s [23-25]; pho on ha es ing [26] and ca alysis [27]. Te py idine de i a i es a e mul i alen py idine ligands ha exhibi s ong binding a ini y owa d a b oad se o ansi ion me al ca ions. This ex emely s ong in e ac ions come bo h om he d-d* back bonding o he ca ions o he N-he e ocycle ings and om he chela e e ec [28,29]. He e, he py s uc u e has been modi ied wi h a polyme izable me hac ylamide g oup and wo kind o ch omogenic senso y ma e ials ha e been p epa ed: linea polyme s and solid ilm-shaped dense memb anes comp ised o c osslinked polyme ne wo ks. The py-monome (~1% mol) was copolyme ized wi h a balance o hyd ophilic and hyd ophobic comme cial co-monome s (~99% mol) o gi e linea copolyme s and ne wo ks (memb anes). The linea polyme s a e wa e soluble. The memb anes a e solid, exhibi gel beha iou , and can be used o p epa e manageable solid senso y ki s. Bo h ype o ma e ials espond wi h de elopmen o di e en colou depending on he p esence o Fe(III), Co(II), Cu(II) and Sn(II) in 100% wa e unde con olled acidic condi ions. The de ec ion in 100% wa e is ele an o eal-li e en i onmen al applica ions, whe eas he acidic condi ions a oid he analy ical complexi y o dealing wi h p esence o di e en species o each ca ion ( o ins ance, o i on a pH 2 only Fe3+ species a e p esen , while a pH > 2 he e a e di e en equilib ia o Fe3+, Fe(OH)2+, Fe(OH)2+, and Fe(OH)3). Also, he usual p esence in mos esea ch s udies o o ganic sol en s, due o he insolubili y in wa e o con en ional p obes, in luence he selec i i y o he py co e [30]. 2. EXPERIMENTAL PART 2.1. Ma e ials Accep edmanusc ip.Publishedmanusc iplink: h p://www.sciencedi ec .com/science/a icle/pii/S0925400515306948 doi:10.1016/j.snb.2015.11.116 5 All ma e ials and sol en s we e comme cially a ailable and used as ecei ed, unless o he wise indica ed: 2-ace ylpy idine (98%, Al a Aesa ), iodine (≥ 99.8%, Sigma- Ald ich), 4-ni obenzaldehyde (99% Al a Aesa ), ammonium ace a e (97%, Al a Aesa ), in chlo ide anhyd ous (98% , Al a Aesa ), me hac yloyl chlo ide (97%, Al a Aesa ), ie hylamine (TEA) (≥ 99%, Ald ich), py idine (≥ 99%, P obus), sodium hyd oxide (99.9%, VWR-P olabo), hyd ochlo ic acid (37%, VWR-P olabo), N-me hyl-2- py olidone (NMP) (99%, Ald ich), e hanol (99.97%, VWR-P olabo), die hyl e he (≥ 99,5%, Ald ich), SnCl2 anhyd ous (98%, Al a Aesa ), Fe(NO3)3·9H2O (VWR-P olabo), Cu(NO3)2·3H2O (98%, Sigma-Ald ich), Co(NO3)2·6H2O (≥ 99%, Labkem), NaCl (≥ 99%, Sigma-Ald ich), KCl (99.5%, Scha lau), Al(NO3)2·9H2O (≥ 989%, Sigma- Ald ich), Pb(NO3)2 (≥ 99%, Fluka), LiCl (≥ 99%, Sigma-Ald ich), Zn(NO3)2·6H2O (98%, Ald ich), Mg(NO3)2·6H2O (≥ 99%, Labkem), Cd(NO3)2 (98.5%, Al a Aesa ), Ni(NO3)2·6H2O (98.5%, Sigma-Ald ich), me hyl me hac yla e (MMA) (99%, Ald ich), 1- inyl-2-py olidone (VP) (≥ 99%, Sigma-Ald ich), e hylene glycol dime hac yla e (EGDMMA) (98%, Sigma-Ald ich), Azo-bis-isobu y oni ile (AIBN, ≥ 98%, Ald ich) was ec ys allised wice om me hanol. 2.2. Ins umen a ion and measu emen s 1H and 13C NMR spec a we e eco ded wi h a Va ian Ino a 400 spec ome e ope a ing a 399.92 and 100.57 MHz, espec i ely, wi h deu e a ed chlo o o m (CDCl3) as he sol en . UV/ is spec a we e eco ded using a Hi achi U-3900 UV/ is spec opho ome e . Accep edmanusc ip.Publishedmanusc iplink: h p://www.sciencedi ec .com/science/a icle/pii/S0925400515306948 doi:10.1016/j.snb.2015.11.116 6 In a ed spec a (FT-IR) we e eco ded wi h a FT/IR-4200 FT-IR Jasco spec ome e wi h an ATR-PRO410-S single e lec ion accesso y. Low- esolu ion elec on impac mass spec a (EI-LRMS) we e ob ained a 70 eV on an Agilen 6890N mass spec ome e . The mog a ime ic analysis (TGA) da a we e eco ded o a 5-mg sample unde a ni ogen o oxygen a mosphe e on a TA Ins umen Q50 TGA analyse a a scan a e o 10ºC min-1. The limi ing oxygen index (LOI) was es ima ed using he ollowing expe imen al Van K e elen equa ion: LOI = 17.5 + 0.4 CR, whe e CR is he cha yield weigh pe cen age a 800ºC, which was ob ained om he TGA measu emen s unde a ni ogen a mosphe e. The wa e -swelling pe cen age (WSP) o he memb ane was ob ained om he weigh s o a d y sample memb ane (ωd) and a wa e -swelled sample memb ane (ωs) as ollows: 100 x [(ωs-ωd)/ωd] ( he memb ane was imme sed in pu e wa e a 20ºC un il he swelled equilib ium was achie ed). To de e mine he ensile p ope ies o he polyme ilms (memb anes), s ips (5 mm in wid h and 30 mm in leng h) we e cu om polyme ilms o 112 and 115µm hickness o Mem1 and Mem2, espec i ely, on a SHIMADZU EZ Tes Compac Table-Top Uni e sal Tes e a 20ºC. Mechanical clamps we e used and an ex ension a e o 5 mm min-1 was applied using a gauge leng h o 9.44 mm. A leas 6 samples we e es ed o each polyme , and he da a was hen a e aged. The limi o de ec ion (LOD) and limi o quan i ica ion we e es ima ed by he ollowing equa ions: LOD = 3.3 x SD/s and LOQ = 10 x SD/s, whe e SD is he s anda d de ia ion o a blank sample and s is he slope o he calib a ion cu e in a egion o low concen a ion o a ge species. Accep edmanusc ip.Publishedmanusc iplink: h p://www.sciencedi ec .com/science/a icle/pii/S0925400515306948 doi:10.1016/j.snb.2015.11.116 7 The quali a i e and quan i a i e ch omogenic esponses o senso y squa es (~5x5 mm) cu om memb anes (Mem1 and Mem2) owa d Fe(III), Co(II), Cu(II) and Sn(II) in wa e solu ion we e s udied by imme sing he squa es in a numbe o sealed ials wi h 1 mL o bu e ed wa e , con aining each ial a known concen a ion o one o he a ge ca ions (pH = 2, bu e : KCl-HCl). The esiden ime was 24 hou s and he empe a u e 25 °C. The quali a i e e alua ion o he sensing pe o mance o he ma e ials was ca ied ou isually. On he o he hand, he quan i a i e s udy was pe o med using a digi al pic u e o he senso y squa es aken wi h a sma phone by ea men o he colou de ini ion da a o each disc (RGB pa ame e s, R = pu ple, G = g een, B = blue). These pa ame e s we e ob ained o each squa e di ec ly a e aking he pho og aph o he se squa es h ough using he app called Colou Me e o a con en ional And oid sma phone ( o each squa e 121 (11 × 11) pixels we e a e aged). The h ee RGB pa ame e s we e educed o one a iable (PC1, p incipal componen 1), using p incipal componen analysis (PCA), which p o ided an accoun o >78% o he in o ma ion on he h ee RGB pa ame e s, hus allowing o he elabo a ion o simple 2D i a ion cu es ([ca ion] s. PC1) wi h concomi an noise educ ion, wi hou a signi ican loss o in o ma ion, and wi h independence o he ype o came a, ligh ing, quali y o he image and so on [31,32]. 2.3. Syn hesis o senso y monome The senso y monome con aining he py-mo i (5) was p epa ed acco ding wi h he p ocedu e schema ically shown in Scheme 1. Scheme 1. Accep edmanusc ip.Publishedmanusc iplink: h p://www.sciencedi ec .com/science/a icle/pii/S0925400515306948 doi:10.1016/j.snb.2015.11.116 8 Syn hesis o 3-(4-ni ophenyl)-1-(py idine-2-yl)p op-2-en-1-one (1). 2.5 mL o an aqueous solu ion o 10% NaOH was added o a suspension o 6.25 g (41.4 mmol) o 4- ni obenzaldehyde in 50 mL o e hanol. To he esul ing mix u e cooled a 0 ºC, 5.0 g (41.2 mmol) o 2-ace ylpy idine was added d opwise o 3 h. The solu ion was s i ed a 0 ºC o 2 h. The p ecipi a e o med was collec ed by il a ion and washed wi h e hanol. Yield 6.91 g (66%). 1H NMR H (400 MHz, CDCl3, Me4Si): 8.75 (1H, d, J 4.7 Hz, py idyl-H); 8.42 (1H, d, J 16.1 Hz, CH=CH); 8.26 (2H, d, J 8.8 Hz, Ph); 8.19 (1H, d, J 7.9 Hz, py idyl-H); 7.91 (1H, d, J 16.1 Hz, CH=CH); 7.90 (1H, d, J 7.7 Hz, 1.7 Hz, py idyl-H); 7.85 (2H, d, J 8.9 Hz, Ph); 7.52 (1H,ddd, J 7.5 Hz, 4.7 Hz, 1.2 Hz, py idyl- H). 13C NMR, C (100.6 MHz, CDCl3, Me4Si): 189.06, 153.73, 149.11, 148.67, 141.44, 141.36, 137.32, 129.36, 127.46, 124.94, 124.25, 123.20. EI-LRMS (m/z (%)): 255.07 (18), 254.07 (M+, 100), 226.07 (23), 225.06 (68), 180.07 (18), 179.07 (31), 130.04 (16), 102.04 (29), 79.03 (19), 78.03 (20). FTIR [Wa enumbe s (cm-1)]: a C-H: 3075; C=O: 1671; C=N: 1578; as NO2: 1511; s NO2: 1334. Syn hesis o 1-py idylacylpy idinium iodide (2). To a solu ion o 2 g (15.6 mmol) o 2- ace ylpy idine in 20 mL o py idine 4.60 g (17.6 mmol) o I2 was added and hea ed a 100 ºC unde N2 a mosphe e o 3 h. The mix u e was hen cooled a oom empe a u e and il e ed o and washed wi h e he . The d y solid was hen washed wi h e hanol. A black solid was ob ained. I was immedia ely used in he nex syn he ic s ep because i is sensi i e o ambien condi ions. Yield 4.03 g (75%). 1H NMR H (300 MHz, CDCl3, Me4Si): 8.75 (1H, d, J 4.7 Hz, py idyl-H); 8.42 (1H, d, J 16.1 Hz, CH=CH); 8.26 (2H, d, J 8.8 Hz, Ph); 8.19 (1H, d, J 7.9 Hz, py idyl-H); 7.91 (1H, d, J 16.1 Hz, CH=CH); 7.90 (1H, d, J 7.7 Hz, 1.7 Hz, py idyl-H); 7.85 (2H, d, J 8.9 Hz, Ph); 7.52 (1H, ddd, J 7.5 Hz, 4.7 Hz, 1.2 Hz). Accep edmanusc ip.Publishedmanusc iplink: h p://www.sciencedi ec .com/science/a icle/pii/S0925400515306948 doi:10.1016/j.snb.2015.11.116 9 Syn hesis o 2-(4-(4-ni ophenyl)-6-(py idin-2-yl)py idin-2-yl)py idine (3). To a solu ion o 10% d y ammonium ace a e in 20 mL o e hanol, 1 g (3 mmol) o (2) and 0.78 g (3 mmol) (1) we e added. The mix u e was e luxed o wo days, he sol en emo ed and he p oduc used wi hou u he pu i ica ion. Yield 1.00 g (93%). 1H NMR H (400 MHz, CDCl3, Me4Si): 8.75 (2H, py idyl-H); 8.73 (2H, d, J 4.3 Hz, py idyl-H); 8.68 (2H, d, J 8.0 Hz, py idyl-H); 8.36 (2H, d, J 8.8 Hz, Ph); 8.04 (2H, d, J 8.8 Hz, Ph); 7.90 (2H, d, J 7.8 Hz, 1.6 Hz, py idyl-H); 7.38 (2H, py idyl-H). 13C NMR, C (100.6 MHz, CDCl3, Me4Si):156.53, 155.81, 149.35, 148.33, 148.02, 145.12, 137.17, 128.43, 124.34, 124.34, 121.56, 119.07. EI-LRMS (m/z (%)):355.11 (25), 354.11 (M+, 100), 309.12 (20), 308.12 (78), 306.09 (9), 229.07 (57), 203.06 (4), 177.05 (4), 153.54 (5), 78.02 (5). FTIR [Wa enumbe s (cm-1)]: C=N: 1585; as NO2: 1514; s NO2: 1351. Syn hesis o 4-(2,6-di(py idin-2-yl)py idin-4-yl)benzenamine (4). A mix u e o 3.66 g (10.3 mmol) o (3) and 12.24 g (64.5 mmol) o anhyd ous in(II) chlo ide in concen a ed hyd ochlo ic acid (100 mL) was hea ed a 70 °C o 6 h. The solid was il e ed o and s i ed in a 10% aqueous solu ion o sodium hyd oxide o 1 hou . Then i was il e ed o and washed wi h wa e . Yield 3.07 g (92%). 1H NMR H (400 MHz, CDCl3, Me4Si): 8.73 (2H, ddd, J 4.8 Hz, 1.8 Hz, 0.9 Hz, py idyl-H); 8.69 (2H, s, py idyl-H); 8.67 (2H, d , J 8.0 Hz, 1.1 Hz, py idyl-H); 7.87 (2H, d, J 7.7 Hz, 1.8 Hz py idyl-H); 7.78 (2H, d, J 8.5 Hz, Ph); 7.35 (2H, ddd, J 7.5 Hz, 4.8 Hz, 1.2 Hz, py idyl- H); 3.87 (2H, s, NH2). 13C NMR, C (100.6 MHz, CDCl3, Me4Si):156.70, 155.88, 150.14, 149.22, 147.67, 136.95, 128.53, 128.38, 123.81, 121.49, 117.93, 115.37. EI- LRMS (m/z (%)):325.13 (24), 324.13 (M+, 100), 323.12 (19), 296.11 (6), 246.10 (15), 219.09 (6), 162.09 (6), 78 (4). FTIR [Wa enumbe s (cm-1)]: NH2: 3481, 3387; C=N: 1599; NH2: 1338; C-N: 1185. Accep edmanusc ip.Publishedmanusc iplink: h p://www.sciencedi ec .com/science/a icle/pii/S0925400515306948 doi:10.1016/j.snb.2015.11.116  16  6.4x10-8 and 1.9x10-7 M o Co(II)). On he o he hand, he esponse o Cu(II) and Sn(II) was a he complex wi h LOD and LOQ in he sub milimola le el (1.3x10-5 and 3.8x10-5 M o Cu(II) and 1.4x10-5 and 4.2x10-5 M o Sn(II)). Only he low concen a ion egion is shown in Figu e 4. Full i a ion cu es and UV/ is i a ion spec a a e shown in Figu es S6 o S9, ESI. Figu e 2. Figu e 3. Figu e 4. Solid senso y ma e ials gi e simila colou s upon en e ing in o con ac wi h he ca ions (Fe(III), Co(II), Cu(II) and Sn(II)), and he di e ences be ween solu ion an solid s a e o each ca ion, shown in Figu e 2, co espond o concen a ion di e ences and colou pe cep ion and digi aliza ion. Thus, hese ma e ials pe mi ed he p epa a ion o solid i a ion ki s o he isual de ec ion and quan i ica ion o ca ions. Acco dingly, squa es cu om Mem1 allowed o he naked eye s udy o Fe(III) and Co(II) con en by analysing he pu ple and o ange colou de elopmen , espec i ely (Figu e 5a). The lowe sensi i i y o he senso y polyme s owa d Cu(II) and Sn(II), compa ed wi h he sensi i i y owa d Fe(III) and Co(II), was esol ed by inc easing he py senso y mo i s wi hin he memb anes. The e o e, Mem2, which ha e a mola py con en ou imes highe han Mem1, pe mi ed he isual i a ion o Cu(II) and Sn(II) by ollowing he g een and yellow colou de elopmen , espec i ely. The digi al colou o pic u es o senso y squa es (senso y ki s) shown in Figu es 5a and 5b we e used o build i a ion Accep edmanusc ip.Publishedmanusc iplink: h p://www.sciencedi ec .com/science/a icle/pii/S0925400515306948 doi:10.1016/j.snb.2015.11.116  17  cu es wi h quan i ica ion pu poses, as p e iously desc ibed. The i a ion cu e o Fe(III) is shown in Figu e 5c ( he da a and i a ion cu es o Co(II), Cu(II) and Sn(II) a e depic ed in he ESI, Tables S1-S12 and Figu es S10-S13) [31,32]. Figu e 5. 3.6. Response ime The e a e key pa ame e s o senso pe o mance o eal li e measu emen s: eliabili y, accu a eness, en i onmen al ine ness, and sho esponse ime. The esponse ime was calcula ed as ollows: o LCp solu ions by UV/ is spec oscopy as he ime needed o achie e 99% o he abso bance a ia ion (ESI, Figu e S14). This ime was 10, 6, 2, and 12 min o Fe(III), Co(II), Cu(II), Sn(II) espec i ely (ca ions concen a ion o 5x10-6, 5x10-5, 1x10-4, 7.5x10-4 M, espec i ely). The appa en esponse ime o he senso y ilms (memb anes) was slowe because o he di usion o he species in o he memb ane, and he senso y squa es we e le imme sed o e nigh . 3.7. In e e ence s udy The selec i i y o he senso y ma e ials as colo ime ic ansi ion me al ca ion senso s was es ed in he p esence o a b oad se o ca ions (NaCl, KCl, Cu(NO3)2·3H2O, Co(NO3)2·6H2O, Al(NO3)2·9H2O, Pb(NO3)2, LiCl, Zn(NO3)2·6H2O, Mg(NO3)2·6H2O, Cd(NO3)2, SnCl2 and Ni(NO3)2·6H2O, SnCl2, Fe(NO3)3·9H2O,Cu(NO3)2·3H2O, Co(NO3)2·6H2O). Thus, a solu ion o LCp in wa e (pH = 2, bu e : KCl-HCl, concen a ion o senso y mo i s in wa e was 1x10-3 M -equi alen s o pendan senso y py mo i s pe li e-) wi h a cock ail o hese ca ions (concen a ion o each ca ion = 9.09x10-4 M) was used in his s udy. The UV/ is spec a show ha he se o ca ions a e ue in e e en s (ESI, Figu e S15). This is a cause o he b oad chela ing e ec o py Accep edmanusc ip.Publishedmanusc iplink: h p://www.sciencedi ec .com/science/a icle/pii/S0925400515306948 doi:10.1016/j.snb.2015.11.116  18  mo i s. This means ha a ull ange o complexes a e o med, hough only a ew a e colou ed. Acco dingly, eal sample can con ain hese ions a di e en concen a ions and his ac may be a d awback o he iden i ica ion and quan i ica ion o he a ge ca ions. Howe e , he a ge ca ions can also be e alua ed in p esence o hese in e e en s by he s anda d addi ion p ocedu e. Fo ins ance, by adding inc easing and known quan i ies o Fe(III) o he sample con aining he cock ail o 13 ca ions (concen a ion o each ca ion = 1x10-6 M), he Fe(III) concen a ion calcula ed was 1.3x10-6 M, simila o he eal con en , 1.0x10-6 M (ESI, Figu e S16). Fu he mo e, he accu acy o he Fe(III) concen a ion de e mina ion was e i ied by measu ing he ca ion concen a ion in a sample p epa ed wi h ap wa e om ou labo a o y spiked wi h Fe(III), hus emula ing a eal sample. The i a ion cu e was p epa ed using ap wa e ( he i on concen a ion o his ap wa e , de e mined by induc i ely coupled plasma mass spec ome y -ICP-, was abou 19.4 ppb). The Fe(III) concen a ion added o he ap wa e was 1.5x10−6 M, and he calcula ed concen a ion was 1.4x10−6 M, in good acco dance wi h he added Fe(III) concen a ion. In pa allel, he s anda d addi ion me hod pe mi ed he calcula ion o he i on concen a ion o ap wa e , gi ing a esul o 20.3 ppb, also in ag eemen wi h he concen a ion calcula ed by ICP. 3.8. Fo ensic applica ions and me al ecogni ion I on con aining ools lea e a small amoun o me al upon en e ing in o con ac wi h o he su aces. This is ele an in o ensic applica ions whe e i is impo an o de ec he imp in o ce ain objec s in hands, like kni es. In his sense, Figu e 6 and a ideo shows he shape o a lag sc ew in a inge a e holding i wi h wo inge s. A e p essing lag sc ew wi h he inge s, he index inge is p essed on a il e pape imp egna ed wi h an aqueous solu ion o LCp. The i on pa icles a e oxidized by he Accep edmanusc ip.Publishedmanusc iplink: h p://www.sciencedi ec .com/science/a icle/pii/S0925400515306948 doi:10.1016/j.snb.2015.11.116  19  oxygen o he ai , he swea and wa e and ecognized by he py mo i s gi ing ise o he complex o ma ion wi h he concomi an pu ple colou de elopmen (see ideo, ESI). Mo eo e , i is possible o know i a ool has i on in i s composi ion by dipping in a wa e solu ion o LCp. Immedia ely a e imme sion, he solu ion u n pu ple (see Figu e 6 and ideo, ESI). Cobal , a c i ical aw ma e ial [40], can also be analysed in a simila way. Figu e 6 and he ideo (ESI) also shows how a widia d ill bi , which has an i on-based sha wi h a ungs en ca bide (wi h 6-10% o cobal ) blade a he ip o he d ill. A e being ouched wi h a inge , he widia blade lea e on he il e pape , p e iously we wi h he wa e solu ion o LCp, i s o ange imp in su ounded by he pu ple imp in o he i on holding he widia ip. Figu e 6. 4. CONCLUSIONS Te py idine, as a p o en chela ing agen o monoa omic me allic ca ions, has been used o p epa e colo ime ic senso y solid polyme s bo h as wa e soluble linea polyme s and as solid ilms (memb anes). Wa e solu ion o he linea polyme u ned pu ple, o ange, g een o yellow upon being in con ac wi h Fe(III), Co(II), Cu(II) and Sn(II), espec i ely. The colou de elopmen pe mi ed he isual di e en ia ion o he ca ions and he i a ion wi h he UV/ is echnique. The limi o de ec ion was sub-mic omola o Fe(III) and Co(II), and mic omola o Cu(II) and Sn(II). In a simila ashion, he solid ilms ha e gel beha iou and u n colou ed upon imme sing in wa e con aining he a o emen ioned ca ions. Squa es cu om he memb anes (5x5 mm) beha ed as Accep edmanusc ip.Publishedmanusc iplink: h p://www.sciencedi ec .com/science/a icle/pii/S0925400515306948 doi:10.1016/j.snb.2015.11.116  20  solid senso y ki s om which he ca ions could be di e en ia ed and hei concen a ion es ima ed by he naked eye. Pic u es aken o he ki s pe mi ed he i a ion using he colou de ini ion o he senso y squa es as analy ical inpu . The dynamic ange was o i e decades (lowe concen a ion = 1x10-7 M) o Fe(III) and Co(II) and o wo decades (lowe concen a ion = 9x10-5 M) o Cu(II) and Sn(II). The chosen o p o en o ganic chela ing agen s and hei chemical ancho age o polyme backbones ha e p o en o be success ul s a egies o p epa e senso y ma e ials o wa e en i onmen s. The colou ou pu o he senso y sys ems and he manageable solid ki s allowed o he isually use o hese ma e ials by non-specialized pe sonnel and, concomi an ly, po able de ices such as sma phones pe mi he as and cos less quan i ica ion o a ge species. Mo eo e , o ensic applica ions a e en isaged, e.g., he shape o me allic objec s a e en e ing in o con ac wi h hands can be colou e ealed by p essing he hands on pape o co on ab ics we ed wi h wa e solu ions o he linea senso y polyme . Acknowledgmen s The inancial suppo p o ided by he Spanish Minis e io de Economía y Compe i i idad-Fede (MAT2014-54137-R) and by he Conseje ía de Educación – Jun a de Cas illa y León (BU232U13) is g a e ully acknowledged. Apendix A. Supplemen a y da a A ile and a ideo. The ile con aining expe imen al pa (in e media es and monome cha ac e iza ion); s udy o in e ac ion o LCp, Mem1 and Mem2 wi h Fe(III), Co(II), Cu(II), and Sn(II); in e e ence s udy; and esponse ime. The ideo showing he o ensic applica ions and me al ecogni ion o me allic goods wi h solu ions o LCp. Accep edmanusc ip.Publishedmanusc iplink: h p://www.sciencedi ec .com/science/a icle/pii/S0925400515306948 doi:10.1016/j.snb.2015.11.116  21  Re e ences  [1] G. T. Mo gan, F. H. Bu s all, Dehyd ogena ion o py idine by anhyd ous e ic chlo ide, J. Chem. Soc. (1932) 20-30. [2] C. E. Housec o , 4,2′:6′,4′′-Te py idines: di e ging and di e se building blocks in coo dina ion polyme s and me allomac ocycles, Dal on T ans. 43 (2014) 6594-6604. [3]. E. C. Cons able, C. E. Housec o , M. Neubu ge , S. Scha ne , L. J. Sche e , P epa a ion and s uc u al cha ac e isa ion o e py-co ed dend ime s and dend iplexes, Dal on T ans. (2004) 2635- 2642. [4] P. Wang, T. Okamu a, H.-P. Zhou, W.-Y. Sun, Y.-P. Tian, Me al complex wi h e py indine de i a i e ligand as highly selec i e colo ime ic senso o i on(III), Chin. Chem. Le . 24 (2013) 20-22. [5] B. Zhang, Y. Li, W. 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Downloaded: July 14, 2015 (h p://ec.eu opa.eu/en e p ise/policies/ aw-ma e ials/ iles/docs/c m- epo -on-c i ical- aw- ma e ials_en.pd ). 1  Tables Table 1. The mal (TGA) and mechanical p ope ies o ma e ials. The he mal p ope ies we e e alua ed in ine (N2) and oxidizing (syn he ic ai ) a mosphe es. Polyme The mal p ope ies Mechanical p ope ies A mosphe e LOIc) Tensile s en g h, MPa Young’s Modulus, MPa Elonga ion, % N2 Ai T5,a ) °C T10,a ) °C CR, b) % T5,a ) °C T10,a ) °C Mem1 242 344 4 224 318 19.1 33 660 9 Mem2 241 342 4 245 333 19.1 39 730 8 LCp 389 408 1 353 399 17.9 n.a. d) n.a. d) n.a. d) a ) 5% weigh loss (T5), 10% weigh loss (T10); b) CR: cha yield a 800 ºC; c ) limi ing oxygen index, calcula ed om he TGA da a (LOI = 17.5 + 0.4 CR, CR a 800 ºC unde ni ogen).d) n.a.: no applicable. 1  Cap ions G aphical abs ac Films and wa e soluble polyme s as senso y ma e ials o he de ec ion and quan i ica ion o i on, cobal , coppe and in sal s in wa e , and o o ensic applica ions. Schemes Scheme 1. Syn hesis o acylic monome (5). Scheme 2. Syn hesis and chemical s uc u e o senso y linea polyme (LCp). Scheme 3. Syn hesis and chemical s uc u e o senso y memb anes Mem1 and Mem2. The pic u e shows he memb anes a e emo al om he mould. Figu es Figu e 1. UV/ is s udy o he in e ac ion o Fe(III) (M) wi h py-mo i (L) o LCp in wa e (pH = 2, bu e = HCl-KCl): a) abso bance a ia ion spec a. Blue and ed spec a co espond o o ma ion o 1:1 (ML) and 1:2 (ML2) complexes py mo i :Fe(III), espec i ely (inse : sepa a ion o p ocesses wi h indica ion o he isosbes ic poin s); b) abso bance a 567 nm s Fe(III) concen a ion. The con inuous line is he i ing o he da a acco ding wi h Eq. (1) (inse : Job´s plo ( py is mola ac ion o py senso y mo i s, abso bance a 567 nm); and c) he species dis ibu ion. The concen a ion o senso y mo i s in wa e was 1x10-4 M (equi alen s o pendan senso y py mo i s pe li e). Figu e 2. Colou de elopmen senso y ma e ials upon en e ing in o con ac wi hFe(III), Co(II), Cu(II) and Sn(II): a) LCp in wa e solu ion (pH = 2, bu e = KCl-HCl, concen a ion o ca ions = 5x10-4 M). The concen a ion o senso y mo i s in wa e was 0.01 M (equi alen s o pendan senso y py mo i s pe li e); and b) Mem1 a e imme sion in wa e (pH = 2, bu e = KCl-HCl, concen a ion o ca ions = 5x10-4 M, imme sion ime = 24 h). Figu e 3. Ti a ion cu es o Fe(III) and Co(II) wi h aqueous solu ions o LCp (pH = 2, bu e = KCl-HCl, concen a ion o ca ions anging om 6.75x10-8 o 6.57x10-4 M o Fe(III) and 7.99x10-8 o 7.54x10-4 M o Co(II). Inse s: expansion o he low concen a ion egion. The concen a ion o senso y mo i s in wa e was 1x10-4 M o he Fe(III) i a ion and 1x10-3 M o he Co(II) i a ion (equi alen s o pendan senso y py mo i s pe li e). Figu e 4. Ti a ion cu es o : a) Cu(II); and b) Sn(II) wi h aqueous solu ions o LCp (pH = 2, bu e = KCl-HCl, concen a ion o ca ions anging om 1.64x10-5 o 1.46x10- 2  3 M o Cu(II) and 3.44x10-5 o 1.50x10-3 M o Sn(II) M. The concen a ion o senso y mo i s in wa e was 1x10-3 M (equi alen s o pendan senso y py mo i s pe li e). Figu e 5. Visual i a ion o Fe(III), Co(II), Cu(II) and Sn(II) in wa e (pH = 2, bu e = KCl-HCl) wi h squa es cu om Mem1 o Mem2. Each squa e was dipped in he wa e solu ion con aining each ca ion o 24 h. The senso y memb ane and he ca ion concen a ion o he wa e solu ion was: a) memb anes = Mem1, Fe(III) and Co(II) concen a ion, om le o igh : 1x10-7, 5x10-7, 1x10-6, 5x10-6, 1x10-5, 5x10-5, 1x10-4, 5x10-4, 1x10-3, 5x10-3 M; b) memb anes = Mem2, Cu(II) and Sn(II) concen a ion, om le o igh : 9x10-5, 3x10-4, 6x10-4, 9x10-4, 3x10-3, 6x10-3, 9x10-3 M; and c) Fe(III) i a ion cu e ob ained om he pic u e aken o he squa es imme sed in wa e wi h Fe(III) (PC1: p incipal componen 1 ha encompass h ee digi al colou pa ame e s (RGB) o each senso y squa e). Figu e 6. De ec ing i on and cobal wi h a wa e solu ion o LCp (pH = 2, bu e : KCl- HCl, 1.14 mg/mL (concen a ion o senso y mo i s was 1.75x10-3 M -equi alen s o pendan senso y py mo i s pe li e-)): a) shape o a lag sc ew in a inge ; b) colo a ion o he LCp solu ion caused by he i on o he lag sc ew; and c) shape o a widia blade ( ungs en ca bide + 6-10% o cobal ) o a d ill bi . 9  0.0 1.5 3.0 4.5 6.0 7.5 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.00 3.50x10 -5 7.00x10 -5 1.05x10 -4 1.40x10 -4 0.0 0.1 0.2 0.3 0.4 0.5 0.6  Abso bance 567 nm [Fe(III)], 10 3 M Abso bance 567 nm [Fe(III)], M  0.0 1.5 3.0 4.5 6.0 7.5 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.0 3.0x10 -5 6.0x10 -5 9.0x10 -5 1.2x10 -4 1.5x10 -4 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 [Co(II)], 10 3 M  Abso bance 518 nm [Co(II)], M  Abso bance 518 nm Figu e 3. Ti a ion cu es o Fe(III) and Co(II) wi h aqueous solu ions o LCp (pH = 2, bu e = KCl-HCl, concen a ion o ca ions anging om 6.75x10-8 o 6.57x10-4 M o Fe(III) and 7.99x10-8 o 7.54x10-4 M o Co(II). Inse s: expansion o he low concen a ion egion. The concen a ion o senso y mo i s in wa e was 1x10-4 M o he Fe(III) i a ion and 1x10-3 M o he Co(II) i a ion (equi alen s o pendan senso y py mo i s pe li e). 10  0.0 0.5 1.0 1.5 2.0 2.5 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09  Abso bance 450 nm [Cu (II)], 10 4 M a) 0.0 0.2 0.4 0.6 0.8 1.0 0.00 0.05 0.10 0.15 [Sn (II)], 10 3 M  Abso bance 420 nm b) Figu e 4. Ti a ion cu es o : a) Cu(II); and b) Sn(II) wi h aqueous solu ions o LCp (pH = 2, bu e = KCl-HCl, concen a ion o ca ions anging om 1.64x10-5 o 1.46x10-3 M o Cu(II) and 3.44x10-5 o 1.50x10-3 M o Sn(II) M. The concen a ion o senso y mo i s in wa e was 1x10-3 M (equi alen s o pendan senso y py mo i s pe li e).  a) b) c) Fi gu KC l sol u co n co n 5x1 le i a Fe( I (R G Fe(III) Co(II) Cu(II) Sn(II) u e 5. Vis u l -HCl) wi h u ion con a n cen a ion n cen a ion, 0 -4 , 1x10 -3 , o igh : 9 a ion cu e I II) (PC1: G B) o each 10-7 -2 -1 0 1 2 PC1 u al i a ion h squa es c u a ining eac h o he wa e om le o 5x10 -3 M; 9 x10 -5 , 3x1 0 ob ained p incipal c senso y sq u 10-6 1 0 [ o Fe(III), C u om Me m h ca ion o e solu ion o igh : 1x 1 b ) memb a n 0 -4 , 6x10 -4 , om he pi c o mponen u a e). 0 -5 10-4 Fe ( III ) ], M 11 C o(II), Cu( I m 1 o Me m 24 h. T h was: a) m 1 0 -7 , 5x10 - 7 n es = Me m 9x10 -4 , 3 x c u e aken 1 ha enc o 10-3    I I) and Sn( I m 2. Each s q h e senso y emb anes = 7 , 1x10 -6 , 5 x m 2, Cu(II) a n x 10 -3 , 6x10 o he squ a o mpass h e 10-2 I I) in wa e u a e was d i memb an e = Mem1, F x 10 -6 , 1x10 n d Sn(II) c o - 3 , 9x10 -3 M a es imme s e e digi al c (pH = 2, b u i pped in h e e and he F e(III) and -5 , 5x10 -5 , 1 o ncen a io n M ; and c) s ed in wa e c olou pa a u e = e wa e ca ion Co(II) 1 x10 -4 , n , om Fe(III) e wi h me e s  Fi gu HCl, pen d o h ( un g u e 6. De e c 1.14 mg/ m d an senso y h e LCp sol u g s en ca bi d c ing i on a n m L (conce n y py mo i s u ion cause d d e + 6-10% n d cobal w i n a ion o s pe li e-)) d b y he i o o cobal ) o 12 i h a wa e s enso y m o : a) shape o o n o he la g o a d ill bi s olu ion o o i s was 1. o a lag sc e g sc ew; an d . LCp (pH = 75x10 -3 M w in a ing e d c) shape o = 2, bu e : K -equi ale n e ; b) colo a o a widia b K Cl- n s o a ion b lade 1  SUPPORTING INFORMATION Colo ime ic de ec ion and de e mina ion o Fe(III), Co(II), Cu(II) and Sn(II) in aqueous media by ac ylic polyme s wi h pendan e py idine mo i s Mi iam T igo-López, Asunción Muñoz, Sa u nino Ibeas, Felipe Se na, Félix Clemen e Ga cía and José Miguel Ga cía* Depa amen o de Química, Facul ad de Ciencias, Uni e sidad de Bu gos, Plaza de Misael Bañuelos s/n, 09001 Bu gos, Spain. Fax: (+) 34 947 258 831, Tel: (+) 34 947 258 085. E-mail: jm[email p o ec ed] Table o con en s S1. Expe imen al pa . In e media e and monome cha ac e isa ion..…………..... 2 S2. Ti a ion o Fe(III) wi h LCp..……………………………............................... 6 S3. Ti a ion o Co(II) wi h LCp.………...……………………………………….. 6 S4. Ti a ion o Cu(II) wi h LCp.............................................................................. 7 S5. Ti a ion o Sn(II) wi h LCp………………………………………………….. 7 S6. Ti a ion o ca ions wi h pic u es aken o Mem1 and Mem2………………... 8 S6.1. Ti a ion o Fe(III) wi h a pic u e aken o Mem1……………………. 8 S6.2. Ti a ion o Co(II) wi h a pic u e aken o Mem1.……………………. 9 S6.3. Ti a ion o Cu(II) wi h a pic u e aken o Mem2…………………….. 10 S6.4. Ti a ion o Sn(II) wi h a pic u e aken o Mem2…………………….. 11 S7. Response ime……………………………………………………………........ 12 S8. In e e ence s udy...………………………………………………………….... 13 2  S1. Expe imen al pa . In e media e and monome cha ac e isa ion a) NO NO2 b) 4000 3500 3000 2500 2000 1500 1000 500 0 20 40 60 80 100 T ansmi ance (%) Wa enumbe , cm -1  c)  8.8 8.6 8.4 8.2 8.0 7.8 7.6  ppm  d) 190 180 170 160 150 140 130 120  ppm  Figu e S1. Cha ac e isa ion o (3-(4-ni ophenyl)-1-(py idine-2-yl)p op-2-en-1-one (1): a) chemical s uc u e; b) FT-IR; c) 1H NMR; d) 13C NMR (NMR sol en : DMSO-d6). a)  b) 9.5 9.0 8.5 8.0 7.5 7.0  ppm Figu e S2. Cha ac e isa ion o 1-py idylacylpy idinium iodide (2): a) chemical s uc u e; b) 1H NMR (NMR sol en : DMSO-d6). 3  a)   b) 4000 3500 3000 2500 2000 1500 1000 500 20 30 40 50 60 70 80 90 100 Wa enumbe , cm -1 T ansmi ance (%)  c)  8.8 8.6 8.4 8.2 8.0 7.8 7.6 7.4  ppm  d) 160 150 140 130 120  ppm  Figu e S3. Cha ac e isa ion o 2-(4-(4-ni ophenyl)-6-(py idin-2-yl)py idin-2- yl)py idine (3): a) chemical s uc u e; b) FT-IR; c) 1H NMR; d) 13C NMR (NMR sol en : DMSO-d6). 4  a)  b) 4000 3500 3000 2500 2000 1500 1000 500 0 20 40 60 80 100 Wa enumbe , cm-1 T ansmi ance (%)  c) 8.74 8.36 7.98 7.60 7.22 6.84 4.0 3.8  ppm  d) 160 150 140 130 120  ppm  Figu e S4. Cha ac e isa ion o 4-(2,6-di(py idin-2-yl)py idin-4-yl)benzenamine (4): a) chemical s uc u e; b) FT-IR; c) 1H NMR; d) 13C NMR (NMR sol en : DMSO-d6).  5  a)  a) 4000 3500 3000 2500 2000 1500 1000 500 20 30 40 50 60 70 80 90 100 Wa enumbe , cm -1 T ansmi ance (%)  b) 9.0 8.5 8.0 7.5 7.0 6.5 6.0 5.5 2.1 1.8  ppm  c) 170 160 150 140 130 120 20  ppm  Figu e S5. Cha ac e isa ion o N-(4-(2,4-di(py idin-2-y)py idine-4- yl)phenyl)me hac ylamide (5): a) chemical s uc u e; b) FT-IR; c) 1H NMR; d) 13C NMR (NMR sol en : DMSO-d6). 6  S2. Ti a ion o Fe(III) wi h LCp 400 450 500 550 600 650 700 750 800 0.0 0.1 0.2 0.3 0.4 0.5 0.6 [Fe(III)]  Abso bance  nm Blank [Fe(III)] = 6.57x10 - 4 M Figu e S6. UV/Vis i a ion spec a o Fe (III) wi h a wa e solu ion o LCp (pH = 2, bu e = KCl-HCl, concen a ion o ca ions anging om 6.75x10-8 o 6.57x10-4 M). The concen a ion o senso y mo i s in wa e was 1x10-4 M (equi alen s o pendan senso y py mo i s pe li e). S3. Ti a ion o Co(II) wi h LCp 450 500 550 600 650 0.0 0.5 1.0 1.5 2.0  nm  Abso bance [Co(II)] Blank [Co(II)] = 7.54x10 - 4 M Figu e S7. UV/Vis i a ion spec a o Co (II) wi h a wa e solu ion o LCp (pH = 2, bu e = KCl-HCl, concen a ion o ca ions anging om 7x99·10-8 o 7x54·10-4 M). The concen a ion o senso y mo i s in wa e was 1x10-3 M (equi alen s o pendan senso y py mo i s pe li e). 13  S8. In e e ence s udy a) 400 450 500 550 600 650 700 0.0 0.5 1.0 1.5 2.0 2.5 3.0  Abso bance , nm Fe (III) + Co (II) + Sn (II) + Cu (II) Sn (II) Cu (II) Co (II) Fe (III) b) 400 450 500 550 600 650 700 750 800 0.0 0.5 1.0 1.5 2.0 2.5  Abso bance  , nm Fe(III) Na + , K + , Li + , Cu(II), Co(II), Al(III), Pb(II), Zn(II), Mg(II), Cd(II), Sn(II), Ni(II), Fe(III) Figu e S15. In e e ence s udy. Wa e solu ions o LCp (concen a ion o senso y mo i s was 1x10-3 M (equi alen s o pendan senso y py mo i s pe li e)) upon adding a: a) cock ail o ca ions ha o ms colou ed complexes wi h py mo i s (Fe(III), Co(II), Cu(II), Sn(II). Concen a ion o each ca ion = 1.3x10-3 M); b) cock ail o 13 ca ions (Na+, K+, Li+, Cu(II), Co(II), Al(III), Pb(II), Zn(II), Mg(II), Cd(II), Sn(II) and Ni(II), Fe(III),Cu(II), Co(II)). Concen a ion o each ca ion = 9.09x10-4 M). a) 504567630693 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08  , nm  Abso bance b) 0.00 2.10x10 -6 4.20x10 -6 6.30x10 -6 0.01 0.02 0.03 0.04 0.05 0.06 0.07  Abso bance [Fe (III)], M Equa ion y = a + b*x Adj. R-Sq 0.9828 Value S anda d E B In e ce 0.0107 0.00188 B Slope 7964.3 429.03007 Figu e S16. S anda d addi ion o an aqueous solu ion o Fe (III) o a wa e solu ion o LCp (concen a ion o senso y mo i s was 2x10-3 M (equi alen s o pendan senso y py mo i s pe li e)) con aining a cock ail o 13 ca ions (Na+, K+, Li+, Cu(II), Co(II), Al(III), Pb(II), Zn(II), Mg(II), Cd(II), Sn(II) and Ni(II), Fe(III),Cu(II), Co (II)). The concen a ion o each ca ion was 1x10-6 M; b) leas squa e i ing o he abso bance a 567 nm s mola concen a ion o Fe(III). (Calcula ed concen a ion o Fe(III) = 1.3x10-6. Real concen a ion o Fe(III) and each ca ion = 1x10-6 M).