样品前处理技术基础理论课件.ppt

样品前处理技术基础理论净化条件的确定：根据化合物理化性质选择使用的SPE类型制作化合物净化洗脱曲线，强溶剂-弱溶剂以不同比例，由弱强逐渐增加洗脱强度，通过仪器测定的回收率来确定最佳的淋洗和洗脱溶剂组成和比例在确定的洗脱溶剂比例条件下，进一步优化洗脱体积。样品前处理技术基础理论SPE使用注意事项及关键控制点根据分析目标物的理化性质选择合适的SPE柱；一般SPE柱要防止干涸；注意控制柱载量，防止穿透过载；严格控制上样液和洗脱液滴速；防止混浊样品堵塞柱子；．．．．．．样品前处理技术基础理论Questions?Questions?Questions?Questions?Questions?ProsandconsofsamplePreptech.Dilution-nocleanuporenrichment,good,simple,fast,cleanhigh-Centrifugation-goodcleanup,separatesbymass,noenrichment,cumbersomeandexpensiveFiltration-noenrichment,goodsimplefastcleanhighdetectionlimitsLiquid/LiquidExtraction,Bestcleanup(multistep),separatesbychemicalproperties,enrichment,cumbersomeautomateandexpensiveSolidPhaseExtraction-goodclean-up,fast,easytoautomate,mostoptions-(vendorsandproducts)TransitiontoMixedmoderetentions.EverythingpreviouslyhasbeenNPorRP.Exploitingpolarityorlackoftodefineretentionandrelease.Wecanexploitanothermeansofretentiontoachieveselectivityalsoandthatisionexchange.CanalsodifferentiatebetweenstrongandweakexchangersWCX：中药中的黄连素，季铵盐MentionnorelativelossofreversephasecapacitywithOasisderivativesReversed-PhaseBackboneForthosethatmaybearenotfamiliarwithOasis,thesearethestructuresofthesorbentsOasisHLB–hydrophilic-lipophilicbalancedco-polymer–reversed-phaseretentionOasisMCX(Mixed-modeCationeXchanger)Strongsulfonate(-SO3H)groupsbondedtoOasis?HLBco-polymer(1meq/g)OasisMAX(Mixed-modeAnioneXchanger)QuaternaryaminebondedtoOasisHLBco-polymer(0.25meq/g)OasisWCX(mixed-modeweakcationexchanger)CarboxylicacidbondedtoOasisHLBco-polymer(0.7meq/g,pKa~5)OasisWAX(mixed-modeweakanionexchanger)PiperazinebondedtoOasisHLB(0.6meq/g,pKa~6)ShowinghereisthehowbasiccompoundsinteractwithOasisMCXSorbent.UnderlowpHbasicanalyteispositivelycharged,soitwillhavedualinteractio