EPA METHOD 9057 Determination of Chloride from HCl-Cl2 Emission

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1、METHOD9057DETERMINATIONOFCHLORIDEFROMHCl/Cl2EMISSIONSAMPLINGTRAIN(METHODS0050AND0051)BYANIONCHROMATOGRAPHY1.0SCOPEANDAPPLICATION1.1Thismethoddescribestheanalyticalprotocolfordeterminationofhydrogenchloride(HCl,CASRegistryNumber7647-01-0)andchloride(Cl2,CASRegistryNumber7782-50-5)in

2、stackgasemissionsamplescollectedfromhazardouswasteandmunicipalwasteincineratorsusingthemidgetimpingerHCl/Cl2samplingtrain(Method0051)ortheisokineticsamplingtrain(Method0050).-1.2Thelowerdetectionlimitis0.1µgofchloride(Cl)permLofsamplesolution.Sampleswithconcentrationswhichexceedthe

3、linearrangeoftheanalyticalinstrumentationmaybediluted.1.3Thismethodisrecommendedforuseonlybyanalystsexperiencedintheuseofionchromatographyandintheinterpretationofionchromatograms.2.0SUMMARYOFMETHODThestoichiometryofHClandCl2collectioninthesamplingtrain(seeMethods0050and0051)isasfol

4、lows:Intheacidifiedwaterabsorbingsolution,TheHClgasissolubilizedandformschlorideions(Cl-)accordingtothefollowingformula:+-HCl+H2O=H3O+ClTheCl2gaspresentintheemissionshasaverylowsolubilityinacidifiedwaterandpassesthrough+-tothealkalineabsorbingsolutionwhereitundergoeshydrolysistofor

5、maproton(H),Cl,andhypochlorousacid(HClO)asshown:+-H2O+Cl2=H+Cl+HClO-Non-suppressedorsuppressedionchromatography(IC)isusedforanalysisoftheCl.AspartofMethods0050and0051,sodiumthiosulfatesolutionisaddedtothecontentsofthehydroxidefilledimpingers,inordertopromotethefollowingreaction.-2-

6、--2-S2O3+4OCl+2OH=2SO4+4Cl+H2O-ConversionofalltheoriginalCl2tothestableClion,andappropriateadjustmentoftheanalysis--calculations,removesthepossibilityofpartialreductionofOCltoClandtheresultinghighbiastotheresults.3.0INTERFERENCESVolatilematerialswhichproducechlorideionsupondissolut

7、ionduringsamplingareinterferencesinthesamplingphaseofthemeasurementofHClemissions,butarenotinterferencesintheMethod9057analyticalphase.ExcessiveamountsofotheranionsmaycauseinterferenceinMethod9057by"tailing"andotherwellknownchromatographiceffects.MethodinterferencesmaybecausedbyCD-

8、ROM9057-1Revision0December