磁性固相萃取与石墨原子吸收光谱联用检测环境水样中的cr

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1、磁性固相萃取与石墨原子吸收光谱联用检测环境水样中的Cr3Magneticsolid-phaseextractioncombinedwithgraphitefurnaceatomicabsorptionspectrometryforspeciationofCr(III)andCr(VI)inenvironmentalwaters摘要abstractAnewapproachofmagneticsolidphaseextraction(MSPE)coupledwithgraphitefurnaceatomicabsorptionspectrometry(GFAAS)hasbeendeveloped

2、forthespeciationofCr(III)andCr(VI)usingzincon-immobilizedsilica-coatedmagneticFe3O4nanoparticles(Zincon–Si–MNPs)astheMSPEabsor-bent.Cr(III)wasquantitativelyreservedontheabsorbentatpH9.1whiletotalCrwasreservedatpH6.5.TheabsorbedCrspecieswereelutedbyusing2mol/LHClanddetectedbyGFAAS.Theconcentrationof

3、Cr(VI)couldbecalculatedbysubtractingCr(III)fromtotalCr.AlltheparametersaffectingtheseparationandextractionefficiencyofCrspeciessuchaspH,extractiontime,concentrationandvolumeofeluent,samplevolumeandinfluenceofco-existingionsweresystematicallyexaminedandtheoptimizedconditionswereestablishedaccordingl

4、y.Thedetectionlimit(LOD)ofthemethodwas0.016and0.011ngmL?1forCr(III)andCr(VI),respectively,withtheenrichmentfactorof100and150.Theprecisionsofthismethod(Relativestandarddeviation,RSD,﹥7)forCr(III)andCr(VI)at0.1ngmL?1were6.0%and6.2%,respectively.Inordertovalidatetheproposedmethod,acertifiedreferencema

5、terialofenvironmentalwaterwasanalyzed,andtheresultofCrspeciationwasingoodagreementwiththecertifiedvalue.ThisMSPE–GFAASmethodhasbeensuccessfullyappliedforthespeciationofCr(III)andCr(VI)inlakeandtapwaterswiththerecoveriesof88–109%forthespikedsamples.Moreover,theMSPEseparationmechanismofCr(III)andCr(V

6、I)basedontheiradsorption–desorptiononZincon–Si–MNPshasbeenexplainedthroughvariousspectroscopiccharacterization磁性固相萃取与石墨炉原子吸收光谱联用的方法用于检测Cr3+和Cr6+，并且此方法用锌试剂固定化的二氧化硅包覆的磁性纳米粒子作为吸附剂。溶液PH9.1时铬（III）进行定量保留在吸附剂上，而pH6.5总铬才开始保留。吸收的Cr采用2mol／LHCl洗脱和用石墨炉原子吸收光谱法检测，Cr（VI）浓度的可以通过总铬减去Cr（Ⅲ）计算出来。影响Cr元素分离和萃取所有参数，对萃取的时间

7、，浓度和样品和洗脱液的体积和共存离子影响进行了系统的研究优化的条件下建立了相应的Cr(III)和Cr(VI)检测限（LOD）分别为0.016ngml-1和0.011ngml-1及富集因子分别为100和150.这种方法的精度（RSD，n=7）为在0.1ngml-1Cr（Ⅲ）和Cr（VI）分别为6%和6.2%。为了验证该方法的有效性，公认的环境水样参考材料进行了分析，结果显示Cr形成与参考值是一致的。固相萃取与石