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GCMS检测三聚氰胺.doc

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GC-MSScreenforthePresenceofMelamine (AdaptedfromFDA/ORAForensicChemistryCenterSOPT015)RevisedApril10,2007 PURPOSE: Thisprocedureprovidesageneralguideforthesamplepreparationandanalysisofwheatglutenandpetfoodmatricesformelamineusinggaschromatography/massspectrometry.ThisprocedureisdesignedtoscreentheTMSderivativeofamethanolextractofthesampleanditincorporatesinstrumentalparameterswhichpermit10.5minuteruntimes. SCOPE: Thisprocedureisapplicabletodrywheatgluten,drypetfood,andwet“cutsandgravy”typepetfood.Thisprocedureinvolvesextractionsinmethanolandthereforepreselectscompoundswhicharesolubleorpartiallysolubleinmethanol.Duetosolubilitylimitationsofmelamineinmethanol,thismethodisintendedtobeaqualitativescreenonly. RESPONSIBILITY: Itistheresponsibilityoftheanalysttonoteanymodificationstothisprocedureintheworksheet. DEFINITIONSANDACRONYMS: TMS–trimethylsilyl SAFETYCONSIDERATIONS: Acceptedsafetymeasuresshouldbeemployedwhenworkingwithchemicalsandpressurizedgases. EQUIPMENT: Agilent5975GC-MSsystemequippedwitha30mDB-5MScolumn(orequivalent)Reacti-Vap–Evaporating/HeatingModule REAGENTS: Methanol:HPLCgradePyridine:CertifiedA.C.S.BSTFAwith1%TMCS:bis(trimethylsilyl)trifluoroacetamidewith1%Trimethylchlorosilane(e.g.SylonBFT,Supelco) QCELEMENTS: Ablankshouldberunattheonsetofeachanalysisandthenrandomlythroughouttheanalysisifthereissuspicionofcarryover.Afortifiedsample(seePartC)shouldbeanalyzedwitheachsetofsamplestodemonstrateeffectivesystemperformance. PROCEDURES(PROCESSDETAILS): ThisproceduremaybeusedwiththeGCoperatingineitherthesplitlessorsplit(1:20)mode.Generally,thesplitlessmodeisadvisableforsampleswheremoresensitivityisrequired.Thesplitmodeissuitablewheresampleavailabilityisnotlimitedandtherecommendedamountcanbeprepared(~0.5gsamplepreparations). A.MethanolExtract(UnderivatizedExtract): UnknownWheatGluten/PetFoodSamples:Transferapproximately0.500gofthesampleintoa20mlscintillationvialandadd5mlmethanol.Vortexbrieflytomix,thensonicatefor10minutes.Centrifugeforapproximately6minutesat4500