Designation:E191−64(Reapproved2011)StandardSpecificationforApparatusForMicrodeterminationofCarbonandHydrogeninOrganicandOrgano-MetallicCompounds1ThisstandardisissuedunderthefixeddesignationE191;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope1.1ThisspecificationcoversapparatusandbasicequipmentforthedeterminationofcarbonandhydrogeninorganicandorganometalliccompoundsalongthelinesoftheconventionalmethodofPregl,butwithmodificationsmoreinlinewithmodernpractice.Owingtothediversityofapparatusbywhichcorrectresultscanbeobtained,thisspecificationisintendedtoindicatewhatisacceptableratherthanwhatismandatory.NOTE1—SpecificationsforseveralitemssubsequentlylistedweredevelopedbytheCommitteefortheStandardizationofMicrochemicalApparatus,DivisionofAnalyticalChemistry,AmericanChemicalSoci-ety.21.2Thevaluesstatedininch-poundunitsaretoberegardedasthestandard.Themetricequivalentsofinch-poundunitsmaybeapproximate.2.ReferencedDocuments2.1ASTMStandards:3E124SpecificationforWeighingandDryingApparatusforMicrochemicalAnalysisE148SpecificationforApparatusforMicrodeterminationofNitrogenbytheDumasMethod(Withdrawn1987)43.OxygenSupply3.1Anycylinderorothersuitablesourceofoxygenfreeofhydrogenandorganicimpuritiesmaybeused.Oxygenpre-paredfromliquidairissatisfactory.4.PressureRegulator4.1Thepressureregulator,showninFig.1andFig.2,5consistingofabellandinlettubesubmergedinasuitableconfiningliquid,shallbeusedtosupplyairoroxygen,orboth,atconstantpressuretothecombustionsystem.Substitutionofafinegas-controlvalveandflowmeterforthepressureregu-latorisoptional.5.DryingandPurifyingTube25.1Theconventionalbubble-containerU-tubeshowninFig.3shallbeusedfordryingandpurifyingtheenteringairoroxygen,orboth.6.Flowmeter6.1Therateofgasflo...
