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1、METHOD9041ApHPAPERMETHOD1.0SCOPEANDAPPLICATION1.1Method9041maybeusedtomeasurepHasanalternativetoMethod9040(exceptasnotedinStep1.3)orincaseswherepHmeasurementsbyMethod9040arenotpossible.1.2Method9041isnotapplicabletowastesthatcontaincomponentsthatmaymaskoral
2、terthepHpapercolorchange.1.3pHpaperisnotconsideredtobeasaccurateaformofpHmeasurementaspHmeters.Forthisreason,pHmeasurementstakenwithMethod9041cannotbeusedtodefineawasteascorrosiveornoncorrosive(seeRCRAregulations40CFR§261.22(a)(1).2.0SUMMARYOFMETHOD2.1Theap
3、proximatepHofthewasteisdeterminedwithwide-rangepHpaper.ThenamoreaccuratepHdeterminationismadeusing"narrow-range"pHpaperwhoseaccuracyhasbeendetermined(1)usingaseriesofbuffersor(2)bycomparisonwithacalibratedpHmeter.3.0INTERFERENCES3.1Certainwastesmayinhibitor
4、maskchangesinthepHpaper.ThisinterferencecanbedeterminedbyaddingsmallamountsofacidorbasetoasmallaliquotofthewasteandobservingwhetherthepHpaperundergoestheappropriatechanges.CAUTION:THEADDITIONOFACIDORBASETOWASTESMAYRESULTINVIOLENTREACTIONSORTHEGENERATIONOFTO
5、XICFUMES(e.g.,hydrogencyanide).Thus,adecisiontotakethissteprequiressomeknowledgeofthewaste.SeeStep7.3.3foradditionalprecautions.4.0APPARATUSANDMATERIALS4.1Wide-rangepHpaper.4.2Narrow-rangepHpaper:Withadistinctcolorchangeforevery0.5pHunit(e.g.,AlkaacidFull-R
6、angepHKit,FisherScientificorequivalent).Eachbatchofnarrow-rangepHpapermustbecalibratedversuscertifiedpHbuffersorbycomparisonwithapHmeterwhichhasbeencalibratedwithcertifiedpHbuffers.Iftheincrementalreadingofthenarrow-rangepHpaperiswithin0.5pHunits,thentheagr
7、eementbetweenthebufferorthecalibratedpHmeterwiththepapermustbewithin0.5pHunits.4.3pHMeter(optional).CD-ROM9041A-1Revision1July19925.0REAGENTS5.1CertifiedpHbuffers:TobeusedforcalibratingthepHpaperorforcalibratingthepHmeterthatwillbeusedsubsequentlytocalibrat
8、ethepHpaper.5.2Diluteacid(e.g.,1:4HCl).5.3Dilutebase(e.g.,0.1NNaOH).6.0SAMPLECOLLECTION,PRESERVATION,ANDHANDLING6.1AllsamplesmustbecollectedusingasamplingplanwhichaddressestheconsiderationsdiscussedinC
