EPA METHOD 3550C Ultrasonic Extraction

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1、METHOD3550CULTRASONICEXTRACTION1.0SCOPEANDAPPLICATION1.1Method3550isaprocedureforextractingnonvolatileandsemivolatileorganiccompoundsfromsolidssuchassoils,sludges,andwastes.Theultrasonicprocessensuresintimatecontactofthesamplematrixwiththeextractionsolvent.1.2Themethodis

2、dividedintotwosections,basedontheexpectedconcentrationoforganicsinthesample.Thelowconcentrationmethod(forindividualorganiccomponentsexpectedatlessthanorequalto20mg/kg)usesalargersamplesizeandthreeserialextractions(lowerconcentrationsaremoredifficulttoextract).Themedium/h

3、ighconcentrationmethod(forindividualorganiccomponentsexpectedatgreaterthan20mg/kg)usesasmallersampleandasingleextraction.1.3Itishighlyrecommendedthattheextractsbesubjecttosomeformofcleanuppriortoanalysis.SeeChapterFour,Sec.4.2.2(Cleanup),forapplicablemethods.1.4Becauseof

4、thelimitedcontacttimebetweenthesolventandthesample,ultrasonicextractionmaynotbeasrigorousasotherextractionmethodsforsoils/solids.Therefore,itiscriticalthatthemethod(includingthemanufacturer'sinstructions)befollowedexplicitly,inordertoachievethemaximumextractionefficiency

5、.SeeSec.7.0foradiscussionofthecriticalaspectsoftheextractionprocedure.Consultthemanufacturer'sinstructionsregardingspecificoperationalsettings.1.5Thismethoddescribesatleastthreeextractionsolventsystemsthatmaybeemployedfordifferentgroupsofanalytes(seeSec.5.4).Thechoiceofe

6、xtractionsolventwilldependontheanalytesofinterest.Nosinglesolventisuniversallyapplicabletoallanalytegroups.Asaresultofconcernsabouttheefficiencyofultrasonicextraction,particularlyatconcentrationsnearorbelowabout10µg/kg,itisimperativethattheanalystdemonstratetheperformanc

7、eofthespecificsolventsystemandoperatingconditionsfortheanalytesofinterestandtheconcentrationsofinterest.Thisdemonstrationappliestoanysolventsystemthatisemployed,includingthosespecificallylistedinthismethod.Ataminimum,suchademonstrationwillencompasstheinitialdemonstration

8、ofproficiencydescribedinSec.8.2ofMethod3500,usingacleanreferencematrix.Method8000describesprocedurestha