ASTM_D_6729_-_20.pdf

Designation:D672920Standard Test Method forDetermination of Individual Components in Spark IgnitionEngine Fuels by 100 Metre Capillary High Resolution GasChromatography1This standard is issued under the fixed designation D6729;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This test method covers the determination of individualhydrocarbon components of spark-ignition engine fuels andtheir mixtures containing oxygenate blends(MTBE,ETBE,ethanol,and so forth)with boiling ranges up to 225 C.Otherlight liquid hydrocarbon mixtures typically encountered inpetroleum refining operations,such as blending stocks(naphthas,reformates,alkylates,and so forth)may also beanalyzed;however,statistical data was obtained only withblended spark-ignition engine fuels.1.2 Based on the cooperative study results,individual com-ponent concentrations and precision are determined in therange of 0.01%mass to approximately 30%mass.Theprocedure may be applicable to higher and lower concentra-tions for the individual components;however,the user mustverify the accuracy if the procedure is used for componentswith concentrations outside the specified ranges.1.3 The test method also determines methanol,ethanol,t-butanol,methyl t-butyl ether(MTBE),ethyl t-butyl ether(ETBE),t-amyl methyl ether(TAME)in spark ignition enginefuels in the concentration range of 1%mass to 30%mass.However,the cooperative study data provided sufficient statis-tical data for MTBE only.1.4 Although a majority of the individual hydrocarbonspresent are determined,some co-elution of compounds isencountered.If this test method is utilized to estimate bulkhydrocarbon group-type composition(PONA)the user of suchdata should be cautioned that some error will be encountereddue to co-elution and a lack of identification of all componentspresent.Samples containing significant amounts of olefinic ornaphthenic(for example,virgin naphthas),or both,constitu-ents above n-octane may reflect significant errors in PONAtype groupings.Based on the gasoline samples in the inter-laboratory cooperative study,this procedure is applicable tosamples containing less than 25%mass of olefins.However,some interfering coelution with the olefins above C7ispossible,particularly if blending components or their higherboiling cuts such as those derived from fluid catalytic cracking(FCC)are analyzed,and the total olefin content may not beaccurate.Caution should also be exercised when analyzingolefin-free samples using this test method as some of theparaffins may be reported as olefins since analysis is basedpurely on retention times of the eluting components.1.4.1 Total olefins in the samples may be obtained orconfirmed,or both,if necessary,by Test Method D1319(percent volume)or other test methods,such as those based onmultidimensional PONA type of instruments(Test MethodD6839).1.5 If water is or is suspected of being present,its concen-tration may be determined,if desired,by the use of TestMethod D1744,or equivalent.Other compounds containingoxygen,sulfur,nitrogen,and so forth,may also be present,andmay co-elute with the hydrocarbons.If determination of thesespecific compounds is required,it is recommended that testmethods for these specific materials be used,such as TestMethods D4815 and D5599 for oxygenates,and D5623 forsulfur compounds,or equivalent.1.6 Annex A1 of this test method compares results of thetestprocedurewithothertestmethodsforselectedcomponents,including olefins,and several group types forseveral interlaboratory cooperative study samples.Althoughbenzene,toluene,and several oxygenates are determined,whendoubtful as to the analytical results of these components,confirmatory analyses can be obtained by using specific testmethods.1.7 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.8 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.04.0L on Gas Chromatography Methods.Current edition approved June 1,2020.Published October 2020.Originallyapproved in 2001.Last previous edition approved in 2014 as D6729 14.DOI:10.1520/D6729-20.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally