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1、METHOD9021PURGEABLEORGANICHALIDES(POX)1.0SCOPEANDAPPLICATION1.1Method9021determinesorganicallyboundhalides(chloride,bromide,andiodide)purgedfromasampleofdrinkingwaterorgroundwater.Theyarereportedaschloride.Thismethodisaquickscreeningprocedurerequiringabout10minutes.Themethodusesaspargingdevice,apy
2、rolysisfurnace,andamicrocoulometric-titrationdetector.1.2Method9021detectspurgeableorganicallyboundchlorine,bromine,andiodine.Fluorinecontainingspeciesarenotdeterminedbythismethod.Method9021measuresPOXconcentrationsrangingfrom5to1,000µg/L.1.3Method9021isrestrictedtouseby,orunderthesupervisionof,an
3、alystsexperiencedintheoperationofapyrolysis/microcoulometerandintheinterpretationoftheresults.2.0SUMMARYOFMETHOD2.1Asampleofwater,protectedagainstthelossofvolatilesbytheeliminationofheadspaceinthesamplingcontainer,istransferredtoapurgingvessel.Thevolatileorganichalidesarepurgedintoapyrolysisfurnac
4、eusingastreamofCO2andthehydrogenhalide(HX)pyrolysisproductistrappedandtitratedelectrolyticallyusingamicrocoulometricdetector.3.0INTERFERENCES3.1Contaminants,reagents,glassware,andothersampleprocessinghardwaremaycauseinterferences.Methodblanksmustberoutinelyruntodemonstratefreedomfrominterferencesu
5、ndertheconditionsoftheanalysis.3.1.1Glasswaremustbescrupulouslyclean.Cleanallglasswareassoonaspossibleafterusebytreatingwithchromatecleaningsolution.Thisshouldbefollowedbydetergentwashinginhotwater.Rinsewithtapwaterandreagentwateranddryat105ECfor1houroruntildry.Glasswarewhichisnotvolumetricshould,
6、inaddition,beheatedinamufflefurnaceat300ECfor15to30minutes(ClassAvolumetricwareshouldnotbeheatedinamufflefurnace).Glasswareshouldbesealedandstoredinacleanenvironmentafterdryingandcoolingtopreventanyaccumulationofdustorothercontaminants.3.1.2Usehighpurityreagentsandgasestominimizeinterferenceproble
7、ms.3.1.3Avoidusingnon-PTFE(polytetrafluoroethylene)plastictubing,non-TFEthreadsealants,orflowcontrollerswithrubbercomponentsinthepurgegasstream.CD-ROM9021-1Revision0July19923.2Samplescanbecontaminatedbydiffusiono
