Designation:D7284−20StandardTestMethodforTotalCyanideinWaterbyMicroDistillationfollowedbyFlowInjectionAnalysiswithGasDiffusionSeparationandAmperometricDetection1ThisstandardisissuedunderthefixeddesignationD7284;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodisusedtodeterminetheconcentrationoftotalcyanideinanaqueouswastewateroreffluent.Thistestmethoddetectsthecyanidesthatarefree(HCNandCN–)andstrong-metal-cyanidecomplexesthatdissociateandreleasefreecyanidewhenrefluxedunderstronglyacidicconditions.1.2Thistestmethodmaynotbeapplicabletoprocesssolutionsfrompreciousmetalsminingoperations.1.3Thisprocedureisapplicableoverarangeofapproxi-mately2to500µg/L(partsperbillion)totalcyanide.Higherconcentrationscanbemeasuredwithsampledilutionorlowerinjectionvolume.1.4ThedeterminativestepofthistestmethodutilizesflowinjectionwithamperometricdetectionbasedonTestMethodD6888.Priortoanalysis,samplesmustbedistilledwithamicro-distillationapparatusdescribedinthistestmethodorwithasuitablecyanidedistillationapparatusspecifiedinTestMethodsD2036.1.5ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.6Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.Specifichazardstatementsaregivenin8.6andSection9.1.7Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoTrade(TBT)Committee.2.ReferencedDocuments2.1ASTMStandar...
