Designation:D7126−15StandardTestMethodforOn-LineColorimetricMeasurementofSilica1ThisstandardisissuedunderthefixeddesignationD7126;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoverstheon-linedeterminationofsolublesilicainwaterbycolorimetricanalysisusingthemolybdenumbluemethod,alsoknownastheheteropolybluemethod.1.2Thistestmethodisapplicableforsilicadeterminationinwaterwithsilicaconcentrationswithin0.5–5000ppb(µg/L).1.3ThistestmethodcoversthedeterminationofsolublesilicaSiO2(silicondioxide)orsilicatesinwater.Solublesilicacompoundsareconsideredmolybdatereactivesilica.Thistestmethoddoesnotcoverthedeterminationofcolloidalorpolymericsilica,whichisconsiderednon-molybdatereactivesilica.1.4Thistestmethoddoesnotcoverthelaboratoryorgrabsamplemeasurementofsilicainwater.RefertoTestMethodD859.1.5ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.6Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2D859TestMethodforSilicainWaterD1066PracticeforSamplingSteamD1129TerminologyRelatingtoWaterD1193SpecificationforReagentWaterD2777PracticeforDeterminationofPrecisionandBiasofApplicableTestMethodsofCommitteeD19onWaterD3370PracticesforSamplingWaterfromClosedConduitsD3864GuideforOn-LineMonitoringSystemsforWaterAnalysisD5540PracticeforFlowControlandTemperatureControlforOn-LineWaterSamplingandAnalysis3.Terminology3.1Definitions—Fordefinitionsoftermsusedinthistestmethod,refertoTerminologyD1129andPracticeD3864.3.2DefinitionsofTermsSpecifictoThisStandard:3.2.1heteropolycompound,n—acomp...
