分子印迹 固相萃取 (3)

SelectiveandsimultaneousdeterminationoftracebisphenolA

andtebuconazoleinvegetableandjuicesamplesbymembrane-basedmolecularlyimprintedsolid-phaseextractionandHPLC

Ya-tingWua,Yan-hongZhanga,MengZhanga,FeiLiua,Ying-chunWana,ZhengHuanga,LeiYea,b,QiZhouc,YunShia,⇑,BinLua,⇑KeyLaboratoryofEnvironmentandHealth,MinistryofEducation&MinistryofEnvironmentalProtection,andStateKeyLaboratoryofEnvironmentalHealth(Incubating),SchoolofPublicHealth,TongjiMedicalCollege,HuazhongUniversityofScienceandTechnology,Wuhan,Hubei430030,ChinabPureandAppliedBiochemistry,CenterforChemistryandChemicalEngineering,LundUniversity,Box124,SE22100Lund,SwedencBureauofHealthSupervision,HealthDepartmentofHubeiProvince,#6ZhuodaoquanNorthStreet,Wuhan,Hubei430079,Chinaaarticleinfoabstract

Nanofibrousmolecularlyimprintedmembranes(nano-MIMs)withmulti-analyteselectivitywerepre-paredbyencapsulatingtwotypesofmolecularlyimprintedpolymernanoparticles(MIP-NPs)intoelec-trospunpolyvinylalcoholnanofibers.Theobtainednano-MIMsmaintainedhighmolecularselectivityofferedbyeachoftheMIP-NPs.Nano-MIMembeddingBPA-imprintednanoparticlesandTBZ-imprintednanoparticlestogethershowedthehighestbindingselectivityforacidbisphenolA(BPA)andbasictebuconazole(TBZ).Thisnano-MIMwasusedasaffinitymaterialofmembrane-basedmolecularlyimprintedsolid-phaseextraction(m-MISPE)toextracttraceBPAandTBZinvegetablesandjuicessimul-taneously.TherecoveriesofBPAandTBZfromdifferentsampleswerehigherthan70.33%withRSDslowerthan9.57%.m-MISPEgavebetterHPLCseparationefficienciesandhigherrecoveriesthanconven-tionalSPEbasedonC18/SCX.Multi-analyteselectivem-MISPEcombinedwithHPLCrealizedselectiveandsimultaneousdeterminationofseveraltraceanalyteswithoppositecharges/polaritiesindifferentfoodsamples.Ó2014ElsevierLtd.Allrightsreserved.Articlehistory:Received1November2013Receivedinrevisedform20April2014Accepted11May2014Availableonline21May2014Chemicalcompoundsstudiedinthisarticle:BisphenolA(PubChemCID:6623)BisphenolC(PubChemCID:6620)BisphenolZ(PubChemCID:232446)Estradial(PubChemCID:5757)Hydroquinone(PubChemCID:785)Tebuconazole(PubChemCID:86102)Hexaconazole(PubChemCID:661)Flutriafol(PubChemCID:91727)Penconazole(PubChemCID:91693)4-Vinylpyridine(PubChemCID:7502)Methacrylicacid(PubChemCID:4093)Azobisisobutyronitrile(PubChemCID:67)trimethylolpropanetrimethacrylate(PubChemCID:186)Keywords:MolecularlyimprintedpolymersElectrospunnanofibrousmembraneBisphenolATebuconazoleMembrane-basedmolecularlyimprintedsolid-phaseextractionVegetableandjuicesamplesAbbreviations:MIP-NPs,molecularlyimprintedpolymernanoparticles;NIP-NPs,non-imprintedpolymernanoparticles;nano-MIMs,molecularlyimprintednanofibrousmembranes;MISPE,molecularlyimprintedsolid-phaseextraction;m-MISPE,membrane-basedmolecularlyimprintedsolid-phaseextraction;r2,coefficientofdetermination;LOD,limitofdetection;LOQ,limitofquantification;RSD,relativestandarddeviation;Kd,dissociationconstant;Bmax,maximumnumberofbindingsites;IPB,imprinting-promotedbinding;SEM,scanningelectronmicroscope;logP,theoctanol–waterpartitioncoeffcient.⇑Correspondingauthors.Tel.:+862783691809;fax:+862783657765(B.Lu).Tel.:+862783657656;fax:+862783657765(Y.Shi).E-mailaddresses:yunshi31@163.com(Y.Shi),lubin@mails.tjmu.edu.cn(B.Lu).http://dx.doi.org/10.1016/j.foodchem.2014.05.0710308-8146/Ó2014ElsevierLtd.Allrightsreserved.528Y.-t.Wuetal./FoodChemistry1(2014)527–5351.IntroductionBisphenolA(BPA)isanacidicendocrinedisrupterandcaninduceadverseeffectsonhumanbeingsandtheecosystem(vomSaal1&Hughes,2005).BPAisacommonmonomerforproducingpolycarbonateplasticsandresinthatareusedasliningsforfoodandbeveragepackaging,asdentalsealants,andasanadditiveinotherwidelyusedconsumerproducts.BPAcanmigratefromcon-tainersintoavarietyoffoodsandbeveragesandthusconsideredtobeapotentialtoxicfoodcontaminant(Sungur,Köroglu,&Özkan,2014;Ferreretal,2011;Cao,Corriveau,&Popovic,2009;Grumetto,Montesano,Seccia,Albrizio,&Barbato,2008;Thomson&Grounds,2005).Tebuconazole(TBZ),abasictriazolefungicide,causessignificantreproductivetoxicityonlaboratorymiceandhasbeenclassifiedasa‘‘possiblehumancarcinogen’’bytheEnvi-ronmentalProtectionAgency(USEPA,1999).TBZiswidelyusedtocontrolrusts,powderymildewsandscabs.Ithasalsobeendetectedinmanyfoodsincludingfruits,vegetables,beveragesandwheatproducts(Lietal.,2012;Fontana,Rodríguez,Ramil,Altamirano,&Cela,2011;Sannino,Bolzoni,&Bandini,2004).BothBPAandTBZareprioritysubstancesinthelistoftheRegis-tration,Evaluation,AuthorizationandRestrictionofChemicals(REACH)(Petry,Knowles,&Meads,2006).TBZisnormallyusedinvegetablesandfruits(Lietal.,2012;Fontanaetal.,2011;Sanninoetal.,2004),whileBPAcanmigratefromfoodcontainerstofoodsandcanbedetectedinmanycannedfoods(Sunguretal.,2014;Thomson&Grounds,2005;Caoetal.,2009;Ferreretal.,2011;Grumettoetal.,2008).Therefore,bothBPAandTBZarelikelytoexistindifferentfoods(especiallycannedvegetablesandfruitfoods)simultaneouslyatlowconcentration.Inordertoevaluatetheirpotentialhealthimpacts,itisimportanttosimultaneouslymeasureBPAandTBZinfoodsampleswithhighaccuracy.Forthispurpose,effectivesamplepre-treatmentisnecessarybeforeBPAandTBZcanbequantifiedusingHPLC,LC–MSorGC–MS(Sunguretal.,2014;Lietal.,2012;Ferreretal.,2011;Fontanaetal.,2011;Caoetal.,2009;Grumettoetal.,2008;Thomson&Grounds,2005;Sanninoetal.,2004).Thecomplexfoodmatricesoftenaffectdetec-tionaccuracy.Furthermore,itisdifficulttosimultaneouslyextracttwotracepollutantswithoppositechargesusingasingleaffinitymaterial.Polymericsolid-phaseextractionsorbents(e.g.OasisHLB)(Gracia-Lor,Sancho,&Hernandez,2010;Weigel,Kallenborn,&Huhnerfuss,2004)andmixed-modephasecolumn(e.g.C18/SCXcolumncontainingC18andcationexchangersulfonicacid(SCX))(Nameraetal.,2011)havebeenusedforsimultaneousextractionofacidicandbasicanalytes.However,theuseofthesenon-selectivesorbentsoftenresultedinco-extractionofmanymatrixcompo-nents.Thelowrecoveriesofsometargetanalyteshavebeenattrib-utedtonon-selectiveinteractionbetweentheanalytesandtheadsorbents(Nameraetal.,2011).Therefore,newaffinityadsorbentsthatcanofferselectiveextractionofbothacidicandbasicanalytesarehighlydesired.Duetotheirhighselectivity,highthermalandchemicalstability,molecularlyimprintedpolymers(MIPs)havebeenappliedasaffin-itysorbentsforselectiveextractionofalargevarietyofanalytes.Inmostcases,MIPsaremadeforrecognitionofonlyonepredeter-minedtarget,whichhaslittlevaluewhenseveralclassesofcom-poundsneedtobeextractedsimultaneously.Presently,MIPsthatareselectiveformultipleanalytesarepreparedbytwomethods:oneistosynthesizeMIPusingmultipletemplatesduringamolecu-larimprintingreaction(multi-templateimprinting),theotheristomixseveralMIPsthathavebeenimprintedseparatelyagainsteachtemplate.Multi-templateimprintingrequirescarefuloptimizationofthesyntheticconditionsbecausethemolecularimprintingeffectforeachtemplatecanvarydramatically.Underdifferentconditions,thebindingcapacityandselectivityofMIPsimprintedagainstmulti-templatesmaybehigher(Jinngetal.,2010;Suedee,Seechamnanturakit,Suksuwan,&Canyuk,2008;Wang,Hong,&Row,2004)orlower(Lejeune&Spivak,2009;Meng,LeJeune,&Spivak,2009;Suedee,Srichana,Chuchome,&Kongmark,2004;Spegel,Schweitz,&Nilsson,2003;Sreenivasan,2001;Sreenivasan&Sivakumar,1999)thanthecorrespondingMIPspreparedagainstsingle-templates.Forexample,MIPspreparedusingbinarytem-plates((S)-propranololand(S)-ropivacaine)showedselectiveuptakeforboth(S)-propranololand(S)-ropivacaine.However,thecapacityandselectivityoftheMIPimprintedagainstthebinary-template(forthetwotemplates)werelowerthanthatoftheMIPsimprintedseparatelyagainst(S)-propranololand(S)-ropivacaine(Spegeletal.,2003).Onepossiblereasonofthepoorerimprintingeffectofthebinary-templateMIPisthatduringthemolecularimprintingreaction,theinteractionbetweenthetwotemplatesleadstotheformationoftemplate–templatecomplexratherthanthedesiredtemplate-functionalmonomercomplex.SimilarresultshavebeenobservedforMIPsimprintedagainstmulti-templatesys-temssuchassalicylicacid-hydrocortisone(Sreenivasan&Sivakumar,1999),cholesterol–testosterone–hydrocortisone(Sreenivasan,2001)andtetracycline–tetracyclinedegradationproducts(Suedeeetal.,2004).Thereductionofenantioselectivityofmulti-templateimprintedMIPshasalsobeendescribedintheliterature(Lejeune&Spivak,2009;Mengetal.,2009).Becauseoftheproblemsencounteredwiththeuseofmulti-templatesformolecularimprinting(i.e.unpredictableimprintingeffectforeachtemplate),wesuggestthatmulti-templateimprintingisnotsuitabletoprepareMIPsforsimultaneousextractionofmultipleanalytescarryingoppositecharges/polari-ties.Inthissituation,thetemplatescaninteractwitheachothertoformtemple–templatecomplexinsteadofformingtemplate-functionalmonomercomplexes,whichwillleadtopoorimprint-ingeffect.Therefore,therouteofmixingseveralsingle-templateimprintedMIPstogainmultipleselectivitiesshouldbefollowed.Previousstudiesinthisdirectionhavefocusedonseparatingmul-tipleanalyteswithsimilarcharges/polarities(Spegeletal.,2003;Sabourin,Ansell,Mosbach,&Nicholls,1998),butnoinvestigationhasbeencarriedouttosimultaneouslyextractbothacidicandbasicanalytesinonestep.Nanofibrousmolecularlyimprintedmembranes(nano-MIMs)canbepreparedbyelectrospinningapolymersolutioncontainingmolecularlyimprintedpolymernanoparticles(MIP-NPs).Thenano-MIMsremainadvantagesofMIP-NPs,suchashighmolecularselectivity,highbindingcapacityandfastbindingkinetics,andatthesametimecanbeusedconvenientlyinpracticalSPEtotreatana-lyticalsamples(Yoshimatsu,Ye,Lindberg,&Chronakis,2008;Chronakis,Jakob,Hagstrom,&Ye,2006).Inthiswork,wedemon-strate,forthefirsttime,thatnano-MIMcontainingdifferenttypesofMIP-NPscanbeusedtorealizesimultaneousextractionofbothacidicandbasicanalyteswithahighselectivity.Electrospunpolyvi-nylalcohol(PVA)nanofibermembranecontainingBPA-imprintedMIP-NPsandTBZ-imprintedMIP-NPsisusedasamodelaffinitysor-bentofmembrane-basedmolecularlyimprintedsolid-phaseextraction(m-MISPE)toextracttracepollutantswithoppositecharge/polarity(BPAandTBZinthiscase)fromvegetableandjuicesamples.Samplepre-treatmentwiththeoptimizedm-MISPEfol-lowedbyHPLCanalysisallowedselectiveandsimultaneousdeter-minationoftraceBPAandTBZwithhighaccuracyandY.-t.Wuetal./FoodChemistry1(2014)527–535529repeatabilitywhensufficientamountofjuices(500mL)orvegeta-bles(200g)wereanalyzed.2.Materials&Methods2.1.ReagentsandchemicalsBisphenolA(BPA),bisphenolC(BPC),bisphenolZ(BPZ),estra-dial(E2),hydroquinone(HQ),tebuconazole(TBZ),hexaconazole(HXZ),flutriafol(FTF),penconazole(PNZ),4-vinylpyridine(4-VP),trimethylolpropanetrimethacrylate(TRIM),polyvinylalcohol(PVA,Mw=,000–98,000and99+%hydrolyzed),HPLCgrademethanolandacetonitrilewereobtainedfromSigma(St.Louis,MO,USA).Azobisisobutyronitrile(AIBN)andmethacrylicacid(MAA)werefromKemioChemicalReagentCompany(Tianjin,China).MAA,4-VPandTRIMwerepurifiedpriortousebyvacuumdistillation.AIBNwasrecrystallizedfrommethanolpriortouse.(Fig.S1(SupplementaryMaterial)listedthechemicalsusedinthisstudy.2.2.ApparatusandanalyticalconditionsHPLCanalysiswasperformedonaWaterssymmetryreversed-phaseoctadecylsilanecolumn(5lmparticles,4.6Â250mm)usingaWaters1525HPLCsystemwith2487dualkabsorbancedetectoroperatingat281nm(forBPAanditsanalogues)and227nm(forTBZanditsanalogues),respectively.Themobilephase(acetonitrile/water/aceticacid=50/47/3,v/v)waspumpedataflowrateof1mLminÀ1.Theinjectedsamplevolumewas10lL.Temperatureofthecolumnovenwassetat25°C.Goodlinearitywasobtainedforalltheninecompoundsinconcentrationsrangedfrom0.1to100lmolLÀ1,withcoefficientofdetermination(r2)higherthan0.999.Thelinearityequation,limitofdetection(LOD,3timesofthesignal-to-noiseratio),andlimitofquantification(LOQ,10timesofthesignal-to-noiseratio)forBPA,BPC,BPZ,E2,HQ,TBZ,HXZ,FTFandPNZwerelistedinTableS1(Supplementarymaterial).2.3.Preparationofmolecularlyimprintedpolymernanoparticles(MIP-NPs)MIP-NPsandnon-imprintedpolymernanoparticles(NIP-NPs)werepreparedbyprecipitationpolymerizationusingconditionsoptimizedinourlab(Huetal.,2007;Zhangetal.,2006).Briefly,thetemplate(BPAorTBZ),thefunctionalmonomer(4-VPorMAA),thecross-linker(TRIM,12mmol)andthefree-radicaliniti-atorAIBN(40mg)weredissolvedinacetonitrileina100mLround-bottomedflask(TableS2).Thesolutionwasdegassedinultrasonicbathfor5minandthenpurgedwithnitrogenfor10min.Theflaskwasthenattachedtoarotorarmandrotatedslowly(atabout50rpm).Thepolymerizationwascarriedoutat65°Cfor24h.Afterpolymerization,theobtainedMIP-NPswerecollected,extractedbymethanol/aceticacid(9/1,v/v)toremovethetemplate,thenwashedwithmethanolandfinallydriedinvacuoovernightat25°C.TheNIP-NPswerepreparedunderiden-ticalconditionsexceptthatthetemplatewasomitted.2.4.Preparationofnanofibrousmolecularlyimprintedmembranes(nano-MIMs)Nano-MIMswerepreparedbyencapsulatingdifferentMIP-NPsorcorrespondingNIP-NPsintoPVAnanofibersthroughelectrospin-ning(Table1).PVA(0.4g)wasfirstdissolvedin7mLwaterbymicrowaveheating.MIP-NPsorcorrespondingNIP-NPswerefirstdispersedbyultrasonicbathin3mLmethanolandthenmixedwiththedissolvedPVAsolution(PVA/nanoparticles=1/1,w/w).ElectrospinningwascarriedoutatroomtemperatureaccordingtoconditionsestablishedbyChronakisetal.(2006).Thespinningvoltagewas15.7kV.Acopperwirewasattachedtothecapillarytip(diameter0.9–1mm)thatactedasthepositiveelectrode.Agroundedaluminumfoil138mmawayfromthecapillarytipwasusedasthecounterelectrode.ContinuousPVAfiberswerecollectedonthealuminumfoil.Afterelectrospinning,thenano-MIMswereplacedinavacuumchamberforatleast24htoremovethesolvent.2.5.MorphologicalstudiesMorphologyofMIP-NPsandthecorrespondingnano-MIMswerestudiedusingaFEISirion200ultra-highresolutionSchottkyfieldemissionscanningelectronmicroscope(SEM)(Hillsboro,OR,USA).ThesizeofMIP-NPorNIP-NPwasdeterminedbydynamiclightscatteringusingaDelsaNanoCAnalyzer(Beckman,USA).Thepar-ticlesweredispersedinmethanolinanultrasonicbathbeforethesizemeasurement.2.6.RebindingtestRebindingtestsofMIP-NPs(inacetonitrile)andcorrespondingnano-MIMs(inacetonitrileandinwater,respectively)werecarriedouttoevaluatethebindingcharacteristicsofthematerials.Ana-logueswithdifferentoctanol–waterpartitioncoefficient(logP)ofBPA(HQ,BPC,BPZ,E2)andTBZ(HXZ,PNZ,FTF)wereusedinrebindingtesttoevaluatethebindingcapacityandbindingselectivityofMIP-NPsandnano-MIMs.Thedissociationconstant(Kd)andmaximumnumberofbindingsites(Bmax)wereusedtoTable1

Preparationandbindingcharacteristicsofnanofibrousmembranes.NanofibermembraneNanoparticles(g)mipBF(mipB)F(nipB)F(mipT)F(nipT)F(mipBT3)F(nipBT3)F(mipB+mipT)F(nipB+nipT)0.4000000.20nipB00.4000000.2mipT000.40000.20nipT0000.40000.2mipBT300000.4000nipBT3000000.400Bmax(Â10À5molgÀ1)InacetonitrileBPA4.322.08n.d.n.d.2.761.963.512.14TBZn.d.n.d.2.191.062.060.832.011.11InwaterBPA4.252.35n.d.n.d.2.702.113.452.30TBZn.d.n.d.2.251.142.131.472.081.59Kd(Â10À5molLÀ1)InacetonitrileBPA2.473.16n.d.n.d5.7411.183.5.32TBZn.d.n.d.5.367.533.267.823.539.49InwaterBPA20.9224.85n.d.n.d.28.5732.1321.3126.TBZn.d.n.d.17.6518.9723.2625.4223.8328.12n.d.:notdetected.F(mipB),F(mipT),F(mipBT3),F(mipB+mipT):nanofibrousmembranescontainingmipB,mipT,mipBT3,mipBandmipTtogether,respectively.F(nipB),F(nipT),F(nipBT),F(nipB+nipT):nanofibrousmembranescontainingnipB,nipT,nipBT,nipBandnipTtogether,respectively.530Y.-t.Wuetal./FoodChemistry1(2014)527–535evaluatebindingspeedandbindingcapacityrespectively.Aparametercalledimprinting-promotedbinding(IPB)wasusedtodescribethebindingselectivity.MIP-NPs(10mg)ornano-MIMs(20mg)wereshakenwithBPA,TBZandtheiranalogues(1mL,1–100lmolLÀ1)inacetonitrileorinwaterat25°Cfor24h.TheamountofBPA,TBZortheiranaloguesinthesupernatantwasdeterminedbyHPLC.Scatchardplotwasconstructedbyplottingtheratioof[Bound]/[Free]against[Bound].KdandBmaxarecalcu-latedfromtheScatchardplotusingtheequation:[Bound]/[Free]=À([Bound]/Kd)+(Bmax/Kd).IPBisdefinedas:IPB=(CMIPÀCNIP)/CNIP.CMIPistheamountofanalyteboundtotheimprintedmaterialandCNIPistheamountofanalyteboundtothenon-imprintedmaterial.2.7.Optimizationofmembrane-basedmolecularlyimprintedsolidphaseextraction(m-MISPE)Nano-MIM(20mg)containingbothBPA-imprintedNPsandTBZ-imprintedNPswasincubatedin1mLwatercontainingBPA,TBZandtheiranalogues(1lmolLÀ1each)for8htoensurecom-pleteadsorptionoftheanalytes.Themembranewasthentrans-ferredinto1mLwashingsolventfor1hundergentleshaking.Finallythemembranewasincubatedin1mLelutingsolventfor8htoelutethetargetanalytes.DifferentSPEconditionswereinvestigatedtofindouttheoptimalprotocol.ConcentrationsoftheanalytesaftereachSPEstepwerequantifiedbyHPLC.C18/SCXhasbeenusedtoextractacidicandbasicanalytessimultaneously(Nameraetal.,2011).Therefore,commercial500mgC18/SCXSPEcolumns(3mL,with50%C18and50%SCX,Cleanext)areusedasreference.OptimizedSPEconditionsfortheC18/SCXcolumnswereused.2.8.Validationofm-MISPEandHPLCanalysisThelinearity,LODandLOQofm-MISPEandHPLCanalysiswereevaluatedusing500mLstandardsolutionscontaining5concentra-tions(0.5,5,50,100and200nmolLÀ1)ofBPA,TBZandtheiranalogues.Thestandardsolutionsweretreatedwith20mgofnano-MIMsundertheoptimizedm-MISPEconditions.Afterm-MISPE,eachanalytewasquantifiedbyHPLC.Theaccuracy,repeatabilityandenrichmentfactorofm-MISPEandHPLCanalysiswereevaluatedbytreatingthreedifferentvol-umes(500,50and5mL)ofstandardsolutionatthreedifferentconcentrations(1,10and100nmolLÀ1)with20mgofnano-MIMs.Afterm-MISPE,eachanalytewasquantifiedbyHPLC.2.9.Foodsamplepre-treatmentOrangejuice,tomatojuice,mixedjuiceandtomatopastawereboughtfromalocalsupermarketatthesametimeandstoredatroomtemperature.ContentsofdifferentjuicesandpastawerelistedinTableS4.Whenanalyzed,thejuices(500mLeach)weredegassedinultrasonicbathfor5minandthenappliedto20mgofnano-MIMsorthecommercialC18/SCXcolumn(500mLorangejuices)respectively.TheC18/SCXSPEextractionconditionswereoptimizedas:conditioningwith15mLmethanolfollowedby3mLwaterwith0.5%aceticacid,directloadingofjuicesample,washingwith3mLwater/methanol(9/1,v/v),andelutingwith3mLof5%ammoniuminmethanol.Cabbageandtomatowereboughtfromalocalmarket.Cabbage,tomato,andtomatopastawerehomogenizedfirst.Thehomoge-nizedsamples(200g)wereextractedby100mLacetoneinanultrasonicbathfor30minandcentrifugedat4000rpmfor10min.Theextractionprocedureswererepeatedthreetimesandthesupernatant(300mL)wereappliedto20mgofnano-MIMsorthecommercialC18/SCXcolumn(200gcabbage)respectively.Afterm-MISPEorconventionalSPEusingC18/SCXcolumns,theelutedanalyteswerequantifiedbyHPLC.Allsampleswereassayedinduplicateandrepeatedtwotimes.2.10.Stabilityofnano-MIMsAfterm-MISPE,nano-MIMswereextractedinmethanol/aceticacid(9/1,v/v)for3timestoregeneratethemembranes.Thenthemembraneswerereusedagain.Morphologiesoftheusedmem-braneswereobservedbySEM.Therecoveriesofthetargetanalytesaftertreatmentwiththeregeneratednano-MIMswerealsomeasured.3.Resultsanddiscussion3.1.PreparationandbindingcharacteristicsofMIP-NPsandcorrespondingnano-MIMsTopreparenano-MIMswithselectivityforBPAandTBZ,westartedfromsynthesizingMIP-NPsthatareabletobindbothBPAandTBZ.TwotypesofMIP-NPswereinvestigated:oneissingle-templateMIP-NPs(mipBandmipT),andtheotheristhebinary-templateMIP-NPs(mipBT1,mipBT2,mipBT3andmipBT4)preparedusingamixtureofBPAandTBZastemplates(TableS2,Supplementarymaterial).Thesingle-templateimprintedmipBandmipThadnarrowsizedistribution(Fig.S2(a–d),TableS2,Supplementarymaterial).Forthebinary-templateimprintedmipBT1,largermicrospheres(2.2lm)wereobtained(Fig.S2(e–f),TableS2,Supplementarymaterial)whentheimprintingreactionwascarriedoutinthesamevolumeofacetonitrileasthatusedforpreparingmipBandmipT.Becauselargeparticlesaredifficulttoencapsulateintonanofibersusingelectrospinning(Chronakisetal.,2006;Yoshimatsuetal.,2008),reactionconditionsforthebinary-templatesystemwerefurtheroptimizedtoreducethefinalparticlesize.AsshowninTableS2andFig.S2,increasingthevolumeofacetonitrilefrom60mLto100mLdecreasedthesizeofthebinary-templateimprintedparticlesfrom2.2lm(mipBT1)to0.lm(mipBT3)(Fig.S2(g–j);TableS2,Supplementarymaterial).Theeffectofexcesssolventmaybeexplainedbythattheparticlenucleiformedinprecipitationpolymerizationaremoredifficulttoaggregate(Yoshimatsu,Reimhult,Krozer,Mosbach,Sode,&Ye,2007).Underthesameacetonitrilevolume(100mL),increasingtheamountofthebinarytemplatesincreasedthesizeofmipBT4to3.5lm(Fig.S2(k);TableS2,Supplementarymate-rial).Inthiscase,theacid-baseinteractionbetweentemplates(BPAandTBZ)mayleadtotheformationofmoreBPA-TBZcomplex,whichmaycausethegrowingnucleitoaggregatetoformlargerparticles(Yoshimatsuetal.,2007).Consideringtherequirementsofelectrospinning,mipBT3withthesmallestdiameterwasselectedasthebinary-templateMIP-NPusedinthefurtherexperiments.PVAwaschosenasthesupportingpolymermatrixtoprepareelectrospunnanofibermembranesbecauseofitssafety,biocom-patibilityandchemicalresistance.Normally,surfactantwasneededtoelectrospin>99%hydrolyzedPVA.Treatmentofelectro-spunPVAnanofibermembraneswithmethanolcouldstabilizethefibersagainstdisintegrationwhenthefiberswerebroughtintocontactwithwater,asaresultofincreasedcrystallinityofthenanofibers(Yaoetal.,2003).Inthisstudy,wefoundthatPVAdissolvedinwatercontaining30%methanolcanbeelectrospunsuccessfullywithoutaddinganysurfactant.Underoptimizedelectrospinningconditions,compositenanofiberswithdiameterof0.4–1lmwerereadilyobtained.Theencapsulatednanoparticleswerefoundtodistributeevenlyalongthenanofibers(Fig.1).Theobtainednano-MIMswerestableinwaterandcouldabsorbtargetY.-t.Wuetal./FoodChemistry1(2014)527–535531Fig.1.SEMimagesofnanofibrousmembranes(a)F(mipB),(b)F(nipB),(c)F(mipT),(d)F(nipT),(e)F(mipBT3),(f)F(nipBT3),(g)F(mipB+mipT),(h)F(nipB+nipT).Table2

Imprinting-promotedbinding(IPB)ofnanofibrousmembranes.AnalyteF(mipB)InacetonitrileBPABPCBPZHQE2TBZFTFHXZPNZ1.970.990.820.720.97n.d.n.d.n.d.n.d.Inwater0.820.150.120.550.28n.d.n.d.n.d.n.d.F(mipT)Inacetonitrilen.d.n.d.n.d.n.d.n.d.1.600.920.901.02Inwatern.d.n.d.n.d.n.d.n.d.0.770.370.140.11F(mipBT3)Inacetonitrile1.420.820.910.850.831.380.810.951.08Inwater0.600.140.100.0.210.510.310.150.13F(mipB+mipT)Inacetonitrile1.810.931.100.910.701.620.900.810.83Inwater0.850.190.110.800.220.810.350.120.10n.d.:notdetected.F(mipB),F(mipT),F(mipBT3),F(mipB+mipT):nanofibrousmembranescontainingmipB,mipT,mipBT3,mipBandmipTtogether,respectively.532Y.-t.Wuetal./FoodChemistry1(2014)527–535compoundseffectivelyevenwithoutbeingtreatedwithmethanol(Fig.S3,Supplementarymaterial).Rebindingtestsinacetonitrileshowedthatthebinary-templateMIP-NPshadlowerbindingcapacity(Bmax)andselectivity(IPB)toBPAandTBZthanthecorrespondingsingle-templateMIP-NPs(TablesS2–S3,Supplementarymaterial).Inthebinary-templateimprintingsystem,theacid–baseinteractionbetweenthetwotemplatesandbetweenthetwofunctionalmonomersmayalsobepresentinadditiontoBPA-4-VPandTBZ–MAAinteractions.TheBPA-TBZand4-VP-MAAinteractionscouldreducethenumberofdesiredtemplate-functionalmonomercomplexesduringpoly-merization,therebyleadingtolowermolecularimprintingeffect(Spegeletal.,2003).Becauseofthepotentialusageinaqueoussamples,molecularrecognitionofnano-MIMinacetonitrileandinwaterwastestedseparately.Analogueswithsimilarchemicalstructurebutdifferentoctanol–waterpartitioncoeffcient(logP)wereusedtoevaluatethenon-specificadsorption.Eitherinacetonitrileorinwater,bind-ingcapacity(Bmax)ofnano-MIMswassimilartothatofthecorre-spondingMIP-NPs(Tables1and2;TablesS2–S3).Obviously,theimprintedsitesintheencapsulatedMIP-NPsremainedaccessible.ThesupportingmatrixPVAdidnotaffectsignificantlythebindingcharacteristicsofthecompositenano-MIMs.Infact,theuptakeofBPAandTBZcontributedbythePVAmatrixwaslessthan5%(datanotshowed).Furthermore,F(mipB+mipT)(membranecontainingtwosingle-templatemipBandmipT)displayedhigherbindingcapacity(Bmax)forBPAandTBZthanF(mipBT3)(membranecon-tainingthebinary-templatemipBT3)(Tables1and2).Thecompos-itemembraneF(mipB+mipT)containedseparateandoptimalbindingsitesforbothBPAandTBZ,whichwasnotpossiblefortheF(mipBT3)preparedfromthebinary-templateMIP-NP.Thebindingcapacity(Bmax)ofnano-MIMsinwaterwassimilartothatobservedinacetonitrile,butthedissociationconstant(Kd)ofnano-MIMsinwaterwerehigherthaninacetonitrile(Table1).Kdrelatedtotheexchangerateofnano-MIMsandtemplates.Obvi-ously,templatesreboundfasterinwaterthaninacetonitrilealthoughthetotalamountoftemplatesadsorbedremainedsimilar.Generally,MIPsexhibitedthebestmolecularrecognitionintheimprintingsolvent(Tokonami,Shiigi,&Nagaoka,2009).Bindingselectivity(IPB)ofnano-MIMsinwaterwaslowerthanthatinace-tonitrile(theimprintingsolvent)(Table2).Highnon-specificadsorption(suchashydrophobicinteractionbetweentemplatesandMIP-NPs)inwaterreducedbindingselectivity(Tokonamietal.,2009).Nevertheless,themembranescontainingMIP-NPsTable3

Recoveriesofm-MISPEinstandardsolutionunderoptimalconditions.am-MISPEProcedureRecoveries(%)Wash1hbElute8hcnano-MIMsF(mipB+mipT)F(nipB+nipT)F(mipB+mipT)F(nipB+nipT)BPA6.7±2.839.5±2.088.5±1.856.8±3.3BPC35.3±2.637.5±4.455.6±3.859.3±1.4BPZ38.6±4.750.4±2.553.3±4.8.3±1.7HQ53.6±1.758.4±1.945.7±2.1.3±2.4E275.9±4.677.4±3.423.1±1.821.7±2.6TBZ9.5±1.845.6±2.782.7±6.4.2±3.6HXZ63.5±1.268.7±1.930.7±2.226.4±3.5PNZ61.9±3.776.8±2.330.6±4.420.1±1.8FTF.9±1.479.6±1.131.2±3.422.3±1.2F(mipB+mipT):nanofibrousmembranescontainingmipBandmipT.F(nipB+nipT):nanofibrousmembranescontainingnipBandnipT.a20mgnano-MIMsin1mLwater,1lmolL-1foreachanalyte.bThewashingsolventisacetonitrile/phosphatebuffer(5mM,pH5.5)=6/4.cTheelutionsolventismethanol.Table4

Repeatabilityandrecoveriesofm-MISPEindifferentjuicesandvegetables.SampleBackgroud(nmolkgÀ1)BPAOrangejuice33.220TBZ5.195Spikedconcentration(nmolkgÀ1)BPA011010001101000110100011010001101000110100TBZ011010001101000110100011010001101000110100Measuredconcentration(nmolkgÀ1)BPA33.2224.72436.141119.37829.224.82233.565116.836.30429.47440.812110.842n.d.0.7618.19785.762n.d.0.8278.13878.66168.16651.97862.877133.423TBZ5.1955.05811.49731.919n.d.0.7658.26982.3411.7352.3199.99486.7093.8243.39310.67683.3291.6232.1149.49373.924n.d.0.7077.680.152Repeatability(RSD%)BPA6.727.925.113.615.336.8.876.2.1.153.876.09n.d.7.298.965.43n.d.7.614.443.683.668.335.476.29TBZ8.153.994.624.83n.d.5.766.193.888.697.135.184.357.085.478.173.979.246.315.825.62n.d.9.578.185.67Recovery(%)(n=3)BPA72.2583.62.6180.3584.14.9779.0188.1481.3276.1081.9785.7682.7081.3878.6675.1580.4479.34TBZ81.6575.6687.3876.5082.6982.3484.7885.1685.2370.3377.2380.2680.6181.6772.7470.7076.9880.15Applejuice29.2n.d.Mixedjuice36.3041.735Tomaton.d.3.824Cabbagen.d.1.623Tomatopaste68.166n.d.n.d.:notdetected.Y.-t.Wuetal./FoodChemistry1(2014)527–535533(F(mipB),F(mipT),F(mipB+mipT))stillhadmuchhigherbindingselectivitythanthecorrespondingmembranescontainingtheNIP-NPs(F(nipB),F(nipT),F(nipB+nipT))(Table2).Thesedatacon-firmedthatnano-MIMsmaintainedselectivemolecularrecogni-tioninwateralthoughtheselectivityisalittlelowerthanthehighestselectivityobtainedinacetonitrile.Theselectiveadsorp-tionandfastrebindingspeedofnano-MIMsinwaterenablestheirusageasaffinitymaterialstoextracttargetanalytesfromaqueoussamples.BecauseF(mipB+mipT)(membranecontainingtwosin-gle-templateMIP-NPs)hadthehighestbindingcapacity(Bmax)andbindingselectivity(IPB)toBPAandTBZ,itischosenastheaffinitysorbentforSPEinthefollowingexperiments.3.2.Optimizationofm-MISPEWhenF(mipB+mipT)wasusedtoextractBPAandTBZsimulta-neouslyinthepresenceoftheirstructuralanalogues,removingnon-specificadsorptionusingoptimizedwashingsolventswascriticaltogetthebestSPEefficiency.Afterbeingincubatedin1mLwatercontainingallthetestcompounds(1lmolLÀ1each)for8h,F(mipB+mipT)(20mg)waswashedindifferentwashingsolventstofindouttheoptimizedwashingsolvent.BecauseMIPsexhibitedthebestmolecularrecognitionintheimprintingsolvent(Tokonamietal.,2009),differentratiosofacetonitrileandwaterweretested.Whenacetonitrile/water=8/2(v/v)wasused,morethan10%BPAandTBZwerewashedoff.Decreasingtheacetoni-trile/waterratioto6/4(v/v)reducedtheamountofcompoundswashedoff.Then,phosphatebuffer(5mM,pH5.5)insteadofwaterwasused.Underthisconditionlessthan10%BPAandTBZcombinedwith30–80%structurallyrelatedanalogueswerewashedoff,producingahigherbindingselectivity(Fig.S4,Supple-mentarymaterial).Cation(Na+andH+)inacidphosphatebuffermightexchangeprotonsinMIP-NPs,whichwouldremovepartofthehydrogenbonddonorgroupsrequiredfortheselectivereten-tion.Thiseffectwasmoresignificantinnon-selectiveabsorptionthaninselectiveretention,somoreanalogueswerewashedawaywhileBPAandTBZretainedonMIP-NPs.SomeofthebindingsitesoftheMIP-NPswerereleasedafterthenon-selectivelyabsorbedanalogueswerewashedaway.ThisallowedmoreBPAandTBZtorebindselectivelytothefreebindingsites.AsfeweranaloguesbutmoreBPAandTBZboundtotheMIP-NPs,thebindingselectiv-itytoBPAandTBZincreased(Huetal.,2007).Therefore,acetoni-trile/phosphatebuffer(5mM,pH5.5)=6/4(v/v)wasselectedastheoptimizedwashingsolvents.Furthermore,asfoodscontainedlargeamountofions,thenegligibleinterferencesofionsontheperformanceofm-MISPEdemonstratedthatm-MISPEwassuitableforpracticalfoodpre-treatment.Theoptimalm-MISPEconditionswereasfollows:(1)sampleloading:incubatingthemembranewithsamplefor8h,(2)wash-ing:incubatingthemembranein1mLacetonitrile/phosphatebuf-fer(5mM,pH5.5)=6/4(v/v)for1h,(3)eluting:incubatingthemembranein1mLmethanolfor8h.Undertheseoptimalm-MISPEconditions,elutionrecoveriesofBPAandTBZ(morethan80%)weremuchhigherthanthose(23.1–55.6%)ofanalogueswithhighlogP(BPC,BPZ,HXZ,PNZandE2)orlowlogP(HQandFTF)(Table3andTableS1).Them-MISPEbasedonF(mipB+mipT)couldextractandenrichBPAandTBZsimultaneouslyintheexistenceofanalogues.3.3.Validationofm-MISPEandHPLC-UVanalysiscanStandardsolutions(0.5,5,50,100and200nmolLÀ1,500mL)ofBPA,TBZandtheiranalogueswereusedtoevaluatethelinearity,LODandLOQofm-MISPEandHPLCanalysis.Whentheenrichmentfactorwas500,goodlinearitywasobtainedforBPAandTBZinconcentrationsrangedfrom0.5to100nmolLÀ1.Thelinearityequationsofthem-MISPEandHPLCanalysisforBPAandTBZwereY=0.1476x+0.0022andY=0.021xÀ0.0078,withr2higherthan0.999,respectively.TheLOQforBPAandTBZwas0.5and0.5nmolLÀ1respectively,withLODof0.2and0.2nmolLÀ1respectively.Whendifferentvolumeofstandardsolutions(enrichmentfac-tor500,50and5)wereappliedtom-MISPEandHPLC,intra-dayrecoverieswerehigherthan84.5%and82.1%withRSDlessthan3.6%and6.8%forBPAandTBZ,respectively.Inter-dayrecoverieswerehigherthan87.3%and80.7%withRSDlessthan4.1%and3.5%forBPAandTBZ,respectively(TableS5,Supplementarymate-rial).Allthesedataindicatedthatm-MISPEcombinedwithHPLCcouldsimultaneouslyextractanddeterminetraceBPAandTBZwithhighaccuracyandrepeatability.3.4.DeterminationoftraceBPAandTBZindifferentfoodsamplesbym-MISPEandHPLCWhensufficientamountofjuices(500mL)orvegetables(200g)wereanalyzedbym-MISPEandHPLC,traceBPA(0–68.166nmolkgÀ1)andTBZ(0–5.195nmolkgÀ1)couldbeextractedanddeterminedsimultaneouslyandaccuratelywithRSDlessthan9.24%.RecoveriesofBPAandTBZwerehigherthan72.25%and70.67%withRSDlowerthan9.15%and9.57%,respectively(Table4).Differentcontentsindifferentjuicesandtomatopasta(TableS4,Supplementarymaterial)didnotaffectrecoveriessignif-icantly.Obviously,pH,sugar,ions,vitaminCandothermaincom-ponentsdidnotinfluencerecoveriesofm-MISPE.Comparedwithrecoveriesachievedusingstandardsolutionsunderoptimalm-MISPEconditions(Table3),recoveriesoffoodsampleswerehigherorlowerduetoanalyticalerrorandtheeffectsoffoodmatrix.Ana-lyticalerrorsmayincreaseorlowertherecoveriesalittlebit.Com-plicatedfoodmatrixcanaffectmolecularrecognitionofMIPstoreducetherecoveries.BPAwasdetectedinallcannedfoods(juicesandtomatopastainthiscase)inconcentrationsrangedfrom29.2to68.166nmolkgÀ1,butnoBPAwasfoundinfreshvegetables(cabbageandtomato).ThesedataindicatedmigratingofBPAfromfoodcontainerstofoods.BPAlev-elsindifferentcannedfoodsindifferentcountriesvariedsignificantly(Sunguretal.,2014;Thomson&Grounds,2005;Caoetal.,2009;Ferreretal.,2011;Grumettoetal.,2008).Foodcontainerswithdif-ferentqualityusedineachcountrymaybepartofthereasonscon-tributedtothesesignificantvariations.UnlikeBPAonlydetectedincannedjuicesandtomatopasta,TBZwasdetectedinbothfreshvegetablesandcannedjuices(orangejuiceandmixedjuices).TBZcontrolledfungiinfectionwhenappliedasfoliarapplicationandasseedtreatmentonvariouscrops.TBZremainedstableunderhydrolysisconditionsincludingsterilization,pasteurization,baking,brewingandboiling(Denmark,2007).Therefore,TBZcanbedetectedeitherinfreshvegetablesorincannedjuices.m-MIPSEnotonlyenrichedtraceBPAandTBZsimultaneously,butalsohadsimilarrecoveriescomparedwithordinaryMISPE.Forexample,recoveriesofthepresentm-MISPEfor1–00nmolkgÀ1BPAspikedjuicesrangedfrom72.25%to.97%(Table4),comparedwith65.8%to82.32%inMISPE(4lmolLÀ1spikedtapwater,urineandplasma)reportedinourpreviousstudy(Zhangetal.,2006).ForTBZ,similarresultswereobserved(75.66–87.38%and72.74–81.67%for1–100nmolkgÀ1spikedorangejuiceorcabbagevs.%and62.3%for5lmolkgÀ1spikedorangejuiceandcabbage,respectively)(Huetal.,2007).Comparedwiththepreviouslyused2–10lmMIPparticlespackedinMISPEcolumns,thesmaller(0.25–0.53lm)andmoreuniformMIP-NPsevenlydis-tributedinthepresentnano-MIMs(Fig.1)providedmoreeasilyaccessiblebindingsites,higherbindingcapacityandselectivity,andfasterbindingkinetics.534Y.-t.Wuetal./FoodChemistry1(2014)527–535Fig.2.Chromatogramsofcabbagedetectedatk=227nmandk=281nm(a).blankcabbageafterm-MISPE;(b).spikedcabbageafterm-MISPE;(c).spikedcabbageafterm-NISPE;(d).spikedcabbageafterC18/SCXSPE;(e).spikedcabbagewithdirectinjection.PeaksinthechromatogramsrelatetoFTF(1),HQ(2),BPA(3),E2(4),BPC(5),BPZ(6),TBZ(7),PNZ(8),HXZ(9).Usingthenano-MIMbasedm-MISPE,therecoveriesofBPA(78.6–88.1%)andTBZ(72.3–85.1%)(Table4)werealsomuchhigherthanthatachievedusingthecommercialC18/SCXSPEcol-umns(48.9–.7%forBPAand49.7–53.2%forTBZ).TheselectiverebindingofBPAandTBZonthenano-MIMwasthereforemuchstrongerthanthenon-specificadsorptionontheC18/SCXsorbent.Useofthenano-MIMsalsoledtofewerinterferingcompoundstoappearinthechromatograms.Smootherbaselines,betterHPLCseparationefficiency,andhigheranalyterecoverieswereachievedafterm-MISPEcomparedwithcommercialC18/SCXSPE(Fig.2).ComparedwithMISPEorC18/SCXSPEwhichneededSPEequip-ments,nano-MIMusedinm-MISPEcanbeputintoliquidsamples(juices)andorganicextractsdirectlywithoutSPEequipments.m-MISPEisquitesimpleandconvenientcomparedwithC18/SCXSPE.3.5.Stabilityofcompositenano-MIMsSEMshowedthatthemorphologyofthenano-MIMsremainedintactaftertheSPEprocess(Fig.S3).Theanalyterecoveriesoftheregeneratedmembranesonlydecreasedslightlycomparedwiththefreshmembranes(TableS5).Thesedatafurtherconfirmedthatthecompositenanofibermembraneswerestableinwaterandcouldbereusedtoextractmultipleanalytes.4.ConclusionInthisstudy,selectivem-MISPEbasedonelectrospunnano-MIMswithmulti-analyteselectivityhasbeendevelopedandusedtoextracttraceBPAandTBZfromdifferentvegetableandjuicesamples.CombiningtheselectivemolecularrecognitionfromtheindividualMIP-NPswasrealizedbyencapsulatingdifferentMIP-NPsintoelectrospunnanofibers.Forthefirsttime,theobtainednano-MIMsmadeitpossibletoselectivelyextracttwotraceana-lytescarryingoppositecharges/polaritiesfromcomplexfoodsam-ples.m-MISPEcanextracttwoanalytesselectivelywithoutusingSPEequipments,whichismoreeffectiveandconvenientthancom-mercialC18/SCXsorbents.Nano-MIMswithmulti-analyteselec-tivityareexpectedtosimplifyanalyticalsamplepreparation,Y.-t.Wuetal./FoodChemistry1(2014)527–535535providingaconvenienttooltobeusedinchemistryandbiologylaboratories.AcknowledgementsThisworkwassupportedbytheNationalNaturalScienceFoun-dationofChina(GrantNo.212770);bytheNationalHighTech-nologyResearchandDevelopmentProgramofChina(863Program)(GrantNo.2012AA06A304),andbytheDoctoralFundofMinistryofEducationofChina(GrantNo.20110142110021).AppendixA.SupplementarydataSupplementarydataassociatedwiththisarticlecanbefound,intheonlineversion,athttp://dx.doi.org/10.1016/j.foodchem.2014.05.071.ReferencesvomSaal1,F.S.,&Hughes,C.(2005).Anextensivenewliteratureconcerninglow-doseeffectsofbisphenolAshowstheneedforanewriskassessment.EnvironmentalHealthPerspectives,113,926–933.Cao,X.L.,Corriveau,J.,&Popovic,S.(2009).LevelsofbisphenolAincannedsoftdrinkproductsinCanadianmarkets.JournalofAgriculturalandFoodChemistry,57,1307–1311.Chronakis,I.S.,Jakob,A.,Hagstrom,B.,&Ye,L.(2006).Encapsulationandselectiverecognitionofmolecularlyimprintedtheophyllineand17b-estradiolnanoparticleswithinelectrospunpolymernanofibers.Langmuir,22,60–65.Denmark(2007).DraftAssessmentReportontebuconazolepreparedbytheDenmarkunderDirective91/414/EEC.Ferrer,E.,Santoni,E.,Vittori,S.,Font,G.,Manes,J.,&Sagratini,G.(2011).SimultaneousdeterminationofbisphenolA,octylphenolandnonylphenolbypressurisedliquidextractionandliquidchromatography–tandemmassspectrometryinpowderedmilkandinfantformulas.FoodChemistry,126,360–367.Fontana,A.R.,Rodríguez,I.,Ramil,M.,Altamirano,J.C.,&Cela,R.(2011).Solid-phaseextractionfollowedbyliquidchromatographyquadrupoletime-of-flighttandemmassspectrometryfortheselectivedeterminationoffungicidesinwinesamples.JournalofChromatographyA,1218,2165–2175.Gracia-Lor,E.,Sancho,J.V.,&Hernandez,F.(2010).Simultaneousdeterminationofacidic,neutralandbasicpharmaceuticalsinurbanwastewaterbyultrahigh-pressureliquidchromatography–tandemmassspectrometry.JournalofChromatographyA,1217,622–632.Grumetto,L.,Montesano,D.,Seccia,S.,Albrizio,S.,&Barbato,F.(2008).DeterminationofbisphenolAandbisphenolBresiduesincannedpeeledtomatoesbyreversed-phaseliquidchromatography.JournalofAgriculturalandFoodChemistry,56,10633–10637.Hu,M.L.,Jiang,M.,Wang,P.,Mei,S.R.,Lin,Y.F.,Hu,X.Z.,etal.(2007).Selectivesolid-phaseextractionoftebuconazoleinbiologicalandenvironmentalsamplesusingmolecularlyimprintedpolymers.AnalyticalandBioanalyticalChemistry,387,1007–1016.Jing,T.,Wang,Y.,Dai,Q.,Xia,H.,Niu,J.,Hao,Q.,etal.(2010).Preparationofmixed-templatesmolecularlyimprintedpolymersandinvestigationoftherecognitionabilityfortetracyclineantibiotics.BiosensorandBioelectronics,25,2218–2224.Lejeune,J.,&Spivak,D.A.(2009).AnalyteseparationbyOMNiMIPsimprintedwithmultipletemplates.BiosensorandBioelectronics,25,604–608.Li,Y.,Dong,F.,Liu,X.,Xu,J.,Li,J.,Kong,Z.,etal.(2012).Enantioselectivedeterminationoftriazolefungicidetebuconazoleinvegetables,fruits,soilandwaterbychiralliquidchromatography/tandemmassspectrometry.JournalofSeperationScience,35,206–215.Meng,A.C.,LeJeune,J.,&Spivak,D.A.(2009).Multi-analyteimprintingcapabilityofOMNiMIPsversustraditionalmolecularlyimprintedpolymers.JournalofMolecularRecognition,22,121–128.Namera,A.,Yamamoto,S.,Saito,T.,Miyazaki,S.,Oikawa,H.,Nakamoto,A.,etal.(2011).Simultaneousextractionofacidicandbasicdrugsfromurineusingmixed-modemonolithicsilicaspincolumnbondedwithoctadecylandcation-exchangegroup.JournalofSeperationScience,34,2232–2239.Petry,T.,Knowles,R.,&Meads,R.(2006).AnanalysisoftheproposedREACHregulation.RegulatoryToxicologyandPharmacology,44,24–32.Sabourin,L.,Ansell,R.J.,Mosbach,K.,&Nicholls,I.A.(1998).Molecularlyimprintedpolymercombinatoriallibrariesformultiplesimultaneouschiralseparations.AnalyticalCommunications,35,285–287.Sannino,A.,Bolzoni,L.,&Bandini,M.(2004).Applicationofliquidchromatographywithelectrospraytandemmassspectrometrytothedeterminationofanewgenerationofpesticidesinprocessedfruitsandvegetables.JournalofChromatographyA,1036,161–169.Spegel,P.,Schweitz,L.,&Nilsson,S.(2003).Selectivitytowardmultiplepredeterminedtargetsinnanoparticlecapillaryelectrochromatography.AnalyticalChemistry,75,6608–6613.Sreenivasan,K.,&Sivakumar,R.(1999).Impartingrecognitionsitesinpoly(HEMA)fortwocompoundsthroughmolecularimprinting.JournalofAppliedPolymerScience,71,1823–1826.Sreenivasan,K.(2001).Molecularlyimprintedpolyacrylicacidcontainingmultiplerecognitionsitesforsteroids.JournalofAppliedPolymerScience,82,8–3.Suedee,R.,Srichana,T.,Chuchome,T.,&Kongmark,U.(2004).Useofmolecularlyimprintedpolymersfromamixtureoftetracyclineanditsdegradationproductstoproduceaffinitymembranesfortheremovaloftetracyclinefromwater.JournalofChromatographyB-AnalyticalTechnologiesintheBiomedicalandLifeSciences,811,191–200.Suedee,R.,Seechamnanturakit,V.,Suksuwan,A.,&Canyuk,B.(2008).Recognitionpropertiesandcompetitiveassaysofadualdopamine/serotoninselectivemolecularlyimprintedpolymer.InternationalJournalofMolecularSciences,9,2333–2356.Sungur,S.,Köroglu,M.,&Özkan,A.(2014).Determinatıonofbisphenolamigratingfromcannedfoodandbeveragesinmarkets.FoodChemistry,142,87–91.Thomson,B.M.,&Grounds,P.R.(2005).BisphenolAincannedfoodsinNewZealand:Anexposureassessment.FoodAdditivesandContaminants,22,65–72.Tokonami,S.,Shiigi,H.,&Nagaoka,T.(2009).Review:Microl-andnanosizedmolecularlyimprintedpolymersforhigh-throughputanalyticalapplications.AnalyticaChimicaActa,1,7–13.USEPA(1999).Tebuconazole:Pesticidetolerance.FederalRegister:RulesandRegulations,,1132–1138.Wa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