Designation:D8351−22StandardTestMethodforDeterminationofTraceElementsinBiodieselandBiodieselBlendsbyMicrowavePlasmaAtomicEmissionSpectrometry(MP-AES)1ThisstandardisissuedunderthefixeddesignationD8351;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthedeterminationofelementsinbiodieselandbiodieselblendsbymicrowaveplasmaatomicemissionspectrometry(MP-AES).Thespecificelementswithinthescopeofthismethodarecalcium(Ca),magnesium(Mg),phosphorus(P),potassium(K),andsodium(Na).1.2ThistestmethodconformstoPracticeD6300,subection8.4.5,validtestresultrange,andsubsection8.4.6,workingrangespecifications.ThevalidtestresultrangeandworkingrangearerecentadditionstoPracticeD6300,andagraphicalrepresentationusingexamplevaluesisshowninAppendixX2,TestMethodOperatingRange.1.3Methodworkingrange:highexpectedconcentrationlimit=highestILSsamplemeanlowexpectedconcentrationlimit=lowestILSsamplemeanif:lowestILSsamplemean−RlowestILSsamplemean>0;otherwiseitisdeterminedbysolvingforXusingthefollowingequation:X−RX=coarsestresolution,determinedby0.5*σrlowestILSsamplemeanBiodieselandBiodieselBlendsElementMethodWorkingRange(expectedmg/kg)Calcium0.24to15.01Magnesium0.12to11.55Phosphorus1.69to14.24Potassium0.49to13.98Sodium0.90to14.301.4Thistestmethodusesorganicelementalstandardsinorganicsolventsforcalibrationanddoesnotpurporttoquantitativelydetermineinsolubleparticulates.Analyticalre-sultsareparticlesizedependent,andparticleslargerthanafewmicrometerscancauseresultstoappearlow.1.5Elementspresentatmassfractionsabovetheupperlimitofthecalibrationcurvescanbedeterminedwithadditionalappropriatedilutions.ElementsshallbemeasuredatthewavelengthspresentedinTable1.AlternatewavelengthsnotedinAppendixX1maybeusedintherarecaseofspectralinterference.1.6ThevaluesstatedinSIunitsaretober...
