ASTM_D_2789_-_95_2011.pdf

Designation:D278995(Reapproved 2011)Standard Test Method forHydrocarbon Types in Low Olefinic Gasoline by MassSpectrometry1This standard is issued under the fixed designation D2789;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.Scope1.1 This test method covers the determination by massspectrometry of the total paraffins,monocycloparaffins,dicy-cloparaffins,alkylbenzenes,indans or tetralins or both,andnaphthalenes in gasoline having an olefin content of less than3 volume%and a 95%distillation point of less than 210C(411F)as determined in accordance with Test Method D86.Olefins are determined by Test Method D1319,or by TestMethod D875.1.2 It has not been determined whether this test method isapplicable to gasoline containing oxygenated compounds(forexample,alcohols and ethers).1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D86 Test Method for Distillation of Petroleum Products atAtmospheric PressureD875 Method for Calculating of Olefins and Aromatics inPetroleum Distillates from Bromine Number and AcidAbsorption(Withdrawn 1984)3D1319 Test Method for Hydrocarbon Types in Liquid Petro-leum Products by Fluorescent Indicator AdsorptionD2001 Test Method for Depentanization of Gasoline andNaphthasD2002 Practice for Isolation of Representative SaturatesFraction from Low-Olefinic Petroleum Naphthas(With-drawn 1998)33.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 The summations of characteristic mass fragments aredefined as follows(equations are identical to those in 11.1):(43paraffins!5 total peak height of m/e143157171185199.(1)(41monocycloparaffins!5 total peak height of m/e141155169183197.(2)(67dicycloparaffins!5 total peak height of m/e167168181182195196.(3)(77alkylbenzenes!5 total peak height of m/e1771781791911921105110611191120113311341147114811611162.(4)(103indans and tetralins!5 total peak height of m/e1103110411171118113111321145114611591160.(5)(128naphthalenes!5 total peak height of m/e11281141614211551156.(6)T 5 total ion intensity5(411(431(671(771(1031(128.(7)3.1.2 carbon numberby definition,is the average numberof carbon atoms in the sample.3.1.3 mass numberwith a plus sign as superscript,isdefined as the peak height associated with the same massnumber.4.Summary of Test Method4.1 Samples are analyzed by mass spectrometry,based onthe summation of characteristic mass fragments,to determinethe concentration of the hydrocarbon types.The averagenumber of carbon atoms of the sample is estimated from1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04.0M on Mass Spectroscopy.Current edition approved May 1,2011.Published August 2011.Originallyapproved in 1969.Last previous edition approved in 2005 as D278995(2005).DOI:10.1520/D2789-05R11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 spectral data.Calculations are made from calibration datawhich are dependent upon the average number of carbon atomsof the sample.Results are expressed in liquid volume percent.5.Significance and Use5.1 A knowledge of the hydrocarbon composition of gaso-line process streams,blending stocks and finished motor fuelsis useful in following the effect of changes in plant operatingconditions,diagnosing process upsets,blending finished prod-ucts and in evaluating the relationship between compositionand performance properties.6.Apparatus6.1 Mass SpectrometerAny mass spectrometer that passesthe performance test described in Section 8.NOTE1Calibration and precision data for this method were obtainedon Consolidated Electrodynamics Corp.Type 21-101,21-102,and 21-103mass spectrometers.These instruments operated with an ion sourcetemperature at or near 250C and at a constant magnetic field of about3100 to 3500 gauss.Laboratories using either Consolidated Electrody-namics Corp.mass spectrometers that operate with different parameters orinstruments other than this design should check the applicability of thecalibra