spe-通过固相萃取进行样品富集和纯化-waters

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1、SPE——通过固相萃取进行样品富集和纯化为何使用固相萃取（SPE）技术1.您需要从样品中去除特定干扰物，以免它们在目标分析物的检测和定量过程中影响实验结果。在此处所示的示例中，不适当的样品制备方案未能去除干扰物，导致提取物呈现出残留的黄色干扰物，色谱图中目标分析物与多个干扰峰发生了重叠。   2.您需要提高初始样品中目标分析物的浓度，以便所用的分析技术能够更轻松地对其进行检测和准确定量。如果目标分析物可被较强地保留，那么可能需要在SPE色谱柱上加载较大的样品量，随后仅以极小体积的洗脱液将此分析物洗脱下来，由此提高样品中分析物的浓度。   3.您需要去除样品中的干扰物（即使不

2、可见），这些干扰物会在质谱检测中抑制目标分析物的信号。在此处的示例中，蛋白沉淀法无法去除血浆提取物中的磷脂，从而造成严重的离子抑制。优化的复合模式SPE方案可获取最纯净的提取物，并可在最大程度上降低离子抑制效应。 WhatisSolid-PhaseExtraction(SPE)?Don'tbeconfusedbythetermsolid-phaseextraction[SPE].AtypicalSPEdevicehas50timesmoreseparationpowerthanasimple,singleliquid-liquidextraction.SPEisactual

3、lycolumnliquid-solidchromatography.SinceSPEis liquidchromatography[LC],itspracticeisgovernedbyLCprinciples.Asampleisintroducedintoacolumnoracartridgedevicecontainingabedofappropriateparticles,orotherform,ofachromatographicpackingmaterial[stationaryphase].Solvent[mobilephase]flowsthroughthe

4、bed.Bychoosinganappropriatecombinationofmobileandstationaryphases,samplecomponentsmaypassdirectlythroughthecolumnbed,ortheymaybeselectivelyretained.Individualcompoundsinthesampleeachtypicallyappeartotravelatdifferentspeedsthroughthedevice.Usingaweakersolventcausesthemtomoveslowlyand/orbest

5、ronglyretained.Astrongersolventspeedsuptheirpassagethroughthebedandelutestheanalyte(s)inamoreconcentratedvolume.ElutionfromanSPEdeviceisusuallydonebyincreasingthestrengthofthemobilephaseinaseriesofdiscrete,ratherthancontinuous,stepsduringwhichselectedanalytesorinterferencesareeitherfullyre

6、tainedorrapidlyeluted-thisvariationofgradientelutioncalleda stepgradient.Mostcommonly,SPEispracticedusingminiaturecolumnorcartridgedevices.Anexampleisshownhere.Amixtureofthreedyesisloadedontothecartridgeinaweaksolvent,causingstrongsampleretentioninanarrowbandthatappears black atthecolumnin

7、let.Subsequentgradientsteps,eachwithasuccessivelystrongersolvent,areusedtoelutethedyesindividually[yellow,red,thenblue].  TypicalSPEcartridgesarelow-pressuredevices-constructedofsolvent-resistantplasticorglass-filledwithparticles≥30µmindiameter.Suitableflowrat