Designation:D4192−15StandardTestMethodforPotassiuminWaterbyAtomicAbsorptionSpectrophotometry1ThisstandardisissuedunderthefixeddesignationD4192;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thistestmethodcoversthedeterminationoflowamountsofpotassiuminwaters2havinglowsolidscontent.Theapplicablerangeofthistestmethodis0.20to4.0mg/Lwhenusingthe766.5-nmresonanceline.Therangemaybeextendedupwardbydilutionofanappropriatealiquotofsampleorbyusingtheless-sensitive404.4-nmresonanceline.Manyworkershavefoundthatthistestmethodisreliableforpotassiumlevelsto0.02mg/L,butuseofthistestmethodatthislowlevelisdependentontheconfigurationoftheaspiratorandnebulizersystemsavailableintheatomicabsorptionspectrophotometeraswellastheskilloftheanalyst.Theprecisionandbiasdatapresentedareinsufficienttojustifyuseofthistestmethodinthe0.02-mg/Lrange.1.2Thistestmethodhasbeenusedsuccessfullywithspikedreagentwater.Itistheanalyst’sresponsibilitytoensurethevalidityofthistestmethodtootherlowdissolvedsolidsmatrices.1.3ThevaluesstatedinSIunitsaretoberegardedasstandard.Thevaluesgiveninparenthesesaremathematicalconversionstoinch-poundunitsthatareprovidedforinforma-tiononlyandarenotconsideredstandard.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.Foraspecificprecautionarystatement,see8.6.2.ReferencedDocuments2.1ASTMStandards:3D1066PracticeforSamplingSteamD1129TerminologyRelatingtoWaterD1193SpecificationforReagentWaterD2777PracticeforDeterminationofPrecisionandBiasofApplicableTestMethodsofCommitteeD19onWaterD3370PracticesforSamplingWaterfromClosedConduitsD4841PracticeforEstimationofHoldingTimeforWater...
