Designation:D7573−09StandardTestMethodforTotalCarbonandOrganicCarboninWaterbyHighTemperatureCatalyticCombustionandInfraredDetection1ThisstandardisissuedunderthefixeddesignationD7573;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthedeterminationoftotalcarbon(TC),inorganiccarbon(IC),totalorganiccarbon(TOC),dissolvedorganiccarbon(DOC),andnon-purgableorganiccarbon(NPOC)inwater,wastewater,andseawaterintherangefrom0.5mg/Lto4000mg/Lofcarbon.Higherlevelsmaybedeterminedbysampledilution.Thesampleisinjectedontoaquartzbedheatedat680ºC.ThesampleconvertsintoagaseousphaseandforcedthroughalayerofcatalystensuringconversionofallcarboncontainingcompoundstoCO2.Anon-dispersiveinfrared(NDIR)detectormeasurestheresultingCO2.1.2ForTOCandDOCanalysisaportionofthesampleisinjectedtodetermineTCordissolvedcarbon(DC).AportionofthesampleisthenacidifiedandpurgedtoremovetheIC.ThepurgedinorganiccarbonismeasuredasTIC,orDIC.TOCorDOCiscalculatedbysubtractingtheinorganicfractionfromthetotalcarbon.TOC=TC–IC.1.3ForNPOCanalysisaportionofsampleisacidifiedandpurgedtoremoveIC.ThepurgedsampleistheninjectedtodetermineNPOC.1.4Thistestmethodwasusedsuccessfullywithreagentwaterspikedwithpotassiumhydrogenphthalate,sucrose,nicotinicacid,benzoquinone,sodiumdodecylbenzenesulfonate,urea,aceticacid,andhumicacid.Itistheuser’sresponsibilitytoensurethevalidityofthistestmethodforwatersofuntestedmatrices.1.5Thistestmethodisapplicableonlytocarbonaceousmatterinthesamplethatcanbeintroducedintothereactionzone.Thesyringeneedleorinjectoropeningsizegenerallylimitsthemaximumsizeofparticlesthatcanbesointroduced.1.6Inadditiontolaboratoryanalyses,thistestmethodmaybeappliedtostreammonitoring.1.7ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1....
