Designation:D1971−16(Reapproved2021)´1StandardPracticesforDigestionofWaterSamplesforDeterminationofMetalsbyFlameAtomicAbsorption,GraphiteFurnaceAtomicAbsorption,PlasmaEmissionSpectroscopy,orPlasmaMassSpectrometry1ThisstandardisissuedunderthefixeddesignationD1971;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ε1NOTE—TheWTOcaveatwaseditoriallyaddedinNovember2021.1.Scope1.1Mostatomicabsorptionandplasmaemissionspectroscopy,andplasma-massspectrometrictestmethodsrequirethatthemetalsofinterestbedissolvedinaliquidphasebeforebeingintroducedintothespectrophotometer.Thesepracticesdescribedigestionordissolutionprocedureswherebyanalytemetalsassociatedwiththesolidfractionofasamplecanbebroughtintosolutionforsubsequentanalysis.Thefollowingpracticesareincluded:SectionsPracticeA—DigestionwithMineralAcidsandElevatedPressure8through13PracticeB—DigestionwithMineralAcidsandHeatingatAtmosphericPressure14through19PracticeC—In-BottleDigestionwithMineralAcids20through251.2Thesepracticeshavebeendemonstratedtobeapplicabletoawidevarietyofsampletypesandsamplematrices,andinmanycases,willgivecompletedissolutionoftheanalytemetalsofinterest.Theyarebynomeanstheonlydigestionproceduresavailable.1.3Theuserofthesepracticesshouldbecautionedthatthesepracticesmaynotcompletelydissolveallportionsofasample’ssolidphaseandmaynotgivecompleterecoveryofthedesiredanalytemetals.Inthesecases,otherdigestiontechniquesareavailablethatwilleffectcompletedissolutionofasample.Itistheuser’sresponsibilitytoensurethevalidityofthesepracticesforuseontheirparticularsamplematrix,fortheirmetalsofinterest.1.4ThispracticeassumesthatthecriteriaestablishedinGuideD3856canbemet.1.5Thesedigestionprocedureshavebeenselectedfortheirwideapplication,lowcost,andeaseofuse.1.6ThevaluesstatedinSIunitsaretoberegardedasthestandard.T...
