Designation:E147−61(Reapproved2017)StandardSpecificationforApparatusforMicrodeterminationofNitrogenbyKjeldahlMethod1ThisstandardisissuedunderthefixeddesignationE147;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thisspecificationcoversdigestionanddistillationap-paratususedforthemicrodeterminationofnitrogenbytheKjeldahlmethod,andmodificationsthereofatatmosphericpressure.NOTE1—ThisspecificationisbasedonthoseoriginallydevelopedbytheCommitteeonMicrochemicalApparatus,DivisionofAnalyticalChemistry,AmericanChemicalSociety.22.ReferencedDocuments2.1ASTMStandards:3E124SpecificationforWeighingandDryingApparatusforMicrochemicalAnalysis3.Tolerances3.1Thefollowingcommerciallengthtoleranceshallbeadheredto,unlessotherwisespecified:Upto10mm±1mm10to100mm±2mm100to200mm±3mm200mm±4mm4.DigestionFlasks4.1DigestionflasksofthreetypesshallconformtotherequirementsprescribedinTable1andFig.1,Fig.2,andFig.3.Theflasksshallbemadeofshock-resistantglasswithlinearcoefficientofexpansionnotgreaterthan33.5×10−7cm/cm·°C.NOTE2—TheweighingtubesdescribedinSpecificationE124Figs.12–14arerecommendedforintroducingsolidsamplesintothemicroKjeldahldigestionflasks.Combustionboats,Fig.1andFig.2ofSpecificationE124,arerecommendedforusewithwaxyandnonvolatileliquidsamples.5.DigestionRack5.1ThemicroKjeldahldigestionrackshallbeportableandshallconsistofflaskheaters(eithergasorelectric),aflasksupport,andafumeduct.Therackshallbesuppliedwithaheatdeflectormountedundertheburnerstopreventoverheatingofthebenchtop.5.1.1Heaters—Thesourceofheatmaybeeitherelectricorgas.Inoperation,eachheatershallsupplysufficientheattoa30-mLflasktocause15mLofwaterat25°Ctocometoarollingboilinnotlessthan2ormorethan3min.Adeviceshallbeprovidedforregulatingtheamountofheatsuppliedtotheflasksothattheseconditionscanbemet.Theam...
