1、Designation: D2789 95 (Reapproved 2016)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
2、, 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
3、,dicycloparaffins, alkylbenzenes, indans or tetralins or both, andnaphthalenes in gasoline having an olefin content of less than3 % by volume and a 95 % distillation point of less than 210 C(411 F) as determined in accordance with Test Method D86.Olefins are determined by Test Method D1319,orbyTestM
4、ethod 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
5、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 S
6、tandards:2D86 Test Method for Distillation of Petroleum Products andLiquid Fuels at Atmospheric 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Method for Calculating of Olefins and Aromatics inPetroleum Distillates from Bromine Number and AcidAbsorption (Withdrawn 1984)3D1319 Test Method for Hydrocarbon Types in Liquid Petro-leum Pr
7、oducts 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 su
8、mmations of characteristic mass fragments aredefined as follows (equations are identical to those in 11.1):(43 paraffins! 5 total peak height of m/e143157171185199.(1)(41 monocycloparaffins! 5 total peak height of m/e141155169183197. (2)(67 dicycloparaffins! 5 total peak height of m/e167168181182195
9、196. (3)(77 alkylbenzenes! 5 total peak height of m/e1771781791911921105110611191120113311341147114811611162. (4)(103 indans and tetralins! 5 total peak height of m/e1103110411171118113111321145114611591160.(5)(128 naphthalenes! 5 total peak height of m/e11281141614211551156. (6)T 5 total ion intens
10、ity 5(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 spectrom
11、etry, 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, Liquid Fuels, and Lubricants
12、and is the direct responsibility ofSubcommittee D02.04.0M on Mass Spectroscopy.Current edition approved Oct. 1, 2016. Published November 2016. Originallyapproved in 1969. Last previous edition approved in 2011 as D2789 95 (2011).DOI: 10.1520/D2789-05R16.2For referenced ASTM standards, visit the ASTM
13、 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 Internat
14、ional, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1spectral 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 k
15、nowledge 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 pe
16、rformance properties.6. Apparatus6.1 Mass SpectrometerAny mass spectrometer that passesthe performance test described in Section 8.NOTE 1Calibration and precision data for this method were obtainedon Consolidated Electrodynamics Corp. Type 21-101, 21-102, and 21-103mass spectrometers. These instrume
17、nts operated with an ion sourcetemperature at or near 250 C and at a constant magnetic field of about3100 gauss (G) to 3500 G. Laboratories using either Consolidated Elec-trodynamics Corp. mass spectrometers that operate with different param-eters or instruments other than this design should check t
18、he applicabilityof the calibration data in Table 1. If necessary, individual laboratoriesshould develop their own calibration data using the blends described inTable 2.6.2 Sample Inlet SystemAny sample inlet system thatallows the introduction of the text mixture (8.2) without loss,contamination, or
19、change of composition.NOTE 2Laboratory testing has shown that, unless a special samplingtechnique or a heated inlet system is used, relatively large errors will occurin the determination of small quantities of indans, tetralins, and naphtha-lenes.6.3 ManometerA manometer suitable for direct reading
20、inthe 0 mtorr to 100 mtorr (0 Pa to 13 Pa) range is optional.NOTE 3The expression mtorr as used in this procedure replaces theolder (micron) unit of pressure.6.4 Microburet or Constant-Volume Pipet.7. Reference Standards7.1 Samples of the following hydrocarbons will be required:2-methylpentane, 2,4-
21、dimethylpentane, n-octane,methylcyclopentane, methylcyclohexane, cis-1,2-dimethylcyclohexane, benzene, toluene, and p-xylene(WarningExtremely flammable liquids. Benzene is aTABLE 1 Calibration Data43/T 41/T 67/T 77/T 103/T 128/T ReferenceAParaffins:C60.6949 0.3025 0.0019 0.0006 . . (1)C70.7379 0.258
22、3 0.0027 0.0010 . . (3)C80.7592 0.2362 0.0032 0.0014 . . (3)C90.7462 0.2350 0.0052 0.0021 . 0.0113 (12)C100.7772 0.2007 0.0056 0.0014 . 0.0151 (13)Monocycloparaffins:C60.1234 0.8218 0.0460 0.0086 . . (1)C70.0731 0.8213 0.0952 0.0104 . . (3)C80.0737 0.8279 0.0866 0.0117 . . (3)C90.0884 0.8029 0.0942
23、0.0140 0.0003 0.0003 (12)C100.1471 0.6272 0.2176 0.0080 . . (13)Dicycloparaffins:C80.0057 0.1848 0.7843 0.0246 0.0004 . (4)C90.0171 0.2270 0.7070 0.0483 0.0005 . (5)C100.0114 0.2973 0.6582 0.0324 0.0006 . (6)Alkylbenzenes:C60.0004 0.0004 . 0.9992 . . (2)C70.0146 0.0120 0.0007 0.9726 . . (3)C80.0033
24、0.0112 0.0007 0.9488 0.0359 . (3)C90.0061 0.0218 0.0020 0.9103 0.0598 . (12)C100.0095 0.0350 0.0025 0.8656 0.0839 0.0034 (13)Indans and tetralins:C90.0144 0.0101 0.0002 0.1600 0.8154 . (7)C100.0062 0.0123 0.0044 0.2314 0.7236 0.0222 (8)C110.0231 0.0199 0.0017 0.1619 0.7456 0.0477 (9)Naphthalenes:C10
25、C110.01210.07020.00370.01400.00080.00110.05810.01720.00650.00180.91880.8957(10)(11)AReferences to source of calibration data:(1) National cooperative by letter of Nov. 22, 1965.(2) Local task group cooperative by meeting of March 1966.(3) National cooperative by letter of Aug. 6, 1962.(4) API No. 44
26、8, 100 %, bicyclo-(3.3.0)-octane.(5) Shell data, 100 %, for 1-methyl-cis-(3.3.0)-bicyclooctane.(6) API No. 412, 100 %, trans-decalin.(7) Unweighted API No. 413 and No. 1214 spectra of indan.(8) API No. 1103, 13 %; API No. 1104, 13 %; API No. 941, 37 %; API No. 539, 37 %.(9) Unweighted averages of AP
27、I Nos. 1216, 1106, 1107, 1108, 1109.(10) Unweighted average of local task group (3 laboratories) data.(11) Unweighted average of API No. 990 and No. 991.(12) National cooperative by letter of Oct. 11, 1967.(13) Proposed Method of Test for Hydrocarbon Types in Low Olefinic Gasoline by Mass Spectromet
28、ry; Appendix VII D2-1958.D2789 95 (2016)2poison, carcinogen, and is harmful or fatal if swallowed.). Onlyreagent grade chemicals conforming to the specifications of theCommittee on Analytical Reagents of the American ChemicalSociety,4National Institute of Standards and Technology(NIST) standard hydr
29、ocarbon samples, or other hydrocarbonsof equal purity should be used.8. Performance Test8.1 Calibration for Test MixtureCalibrate the instrumentin accordance with the manufacturers instructions for thecompounds listed in 7.1, using the same manipulative tech-nique as described in 10.2. Express the c
30、alibration data in unitsof peak height per unit of liquid volume (V) at constantsensitivity. Determine 41/V, 43/ V, and 77/V for each ofthe reference standards and calculate a weighted average valuefor each hydrocarbon group type in accordance with thecomposition of the test mixture as described in
31、8.2. Constructan inverse from the averaged coefficients.NOTE 4The volume, V, ordinarily is expressed as microlitres.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical So
32、ciety, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.TABLE 2 Compositions of Calibration MixturesComponent (Volume Percent) Paraffins Cyclo-paraffinsCyclo
33、-Alkyl-benzenesComponent (Volume Percent) ParaffinsCyclo-paraffinsAlkyl-benzenesC6Blends C9Blendsn-Hexane 46 . . n-Nonane 33 . .2-Methylpentane 28 . . 2-Methyloctane 20 . .3-Methylpentane 20 . . 3-Methyloctane 16 . .2-2-Dimethylbutane 1 . . 4-Methyloctane 8 . .2,3-Dimethylbutane 5 . . 3-Ethylheptane
34、 3 . .Cyclohexane . 46 . 2,6-Dimethylheptane 12 . .Methylcyclopentane . 54 . 2,2-Dimethylheptane 2 . .Benzene . . 100 3,3-Diethylpentane 1 . .C7Blends2,2,5-Trimethylhexane2,2,5-Trimethylhexane21.n-Heptane 45 . . 2,4-Dimethyl-3-ethylpentane 1 . .2-Methylhexane 23 . . 2,2,3,3-Tetramethylpentane 1 . .3
35、-Methylhexane 16 . . n-Propylcyclohexane . 1 .2,2-Dimethylpentane 4 . . Isopropylcyclohexane . 2 .2,3-Dimethylpentane 6 . . 1-Methyl-c-2-ethylcyclohexane . 3 .2,4-Dimethylpentane 5 . . 1-Methyl-t-2-ethylcyclohexane . 4 .3,3-Dimethylpentane 1 . . 1-Methyl-c-3-ethylcyclohexane . 8 .Methylcyclohexane .
36、 57 . 1-Methyl-t-3-ethylcyclohexane . 8 .Ethylcyclopentane . 9 . 1-Methyl-c-4-ethylcyclohexane . 4 .1,1-Dimethylcyclopentane . 4 . 1-Methyl-t-4-ethylcyclohexane . 5 .1,t-2-Dimethylcyclopentane . 14 . 1,c-2, c-3-trimethylcyclohexane . 2 .1,t-3-Dimethylcyclopentane . 16 . 1,t-2, t-3-trimethylcyclohexa
37、ne . 3 .Toluene . . 100 1,t-2,c-3-trimethylcyclohexane . 3 .C8Blends1,t-2,c-4-trimethylcyclohexane1,t-2,t-4-trimethylcyclohexane.1515.n-Octane 39 . . 1,c-3,c-5-trimethylcyclohexane . 5 .2-Methylheptane 19 . . 1,c-3,t-5-trimethylcyclohexane . 5 .3-Methylheptane 16 . . n-Butylcyclopentane . 1 .4-Methy
38、lheptane 8 . . 1,c-2-Diethylcyclopentane . 12 .3-Ethylhexane 3 . . 1,t-2,c-3,t-4-tetramethylcyclopentane . 4 .2,3-Dimethylhexane 4 . . n-Propylbenzene . . 32,4-Dimethylhexane 5 . . Isopropylbenzene . . 12,5-Dimethylhexane 6 . . 1-Methyl-2-ethylbenzene . . 8Ethylcyclohexane . 20 . 1-Methyl-3-ethylben
39、zene . . 191,t-2-Dimethylcyclohexane . 18 . 1-Methyl-4-ethylbenzene . . 111,c-3-Dimethylcyclohexane . 25 . 1,2,3-Trimethylbenzene . . 101,t-4-Dimethylcyclohexane . 11 . 1,2,4-Trimethylbenzene . . 361-Methyl-c-2-ethylcyclopentane . 7 . 1,3,5-Trimethylbenzene . . 121,1,3-Trimethylcyclopentane . 5 .1,t
40、-2,c-3-Trimethylcyclopentane . 9 .1,t-2,c-4-Trimethylcyclopentane . 5 .Ethylbenzene . . 10p-Xylene . . 23m-Xylene . . 46o-Xylene . . 21D2789 95 (2016)3NOTE 5A desk calculator frequently is used for the calculation of 8.1and in such cases small inverse terms can be undesirable. If necessary, itis per
41、missible to divide all averaged coefficients by some suitable constantprior to inversion in order to obtain larger values in the inverse.8.2 Test MixturePrepare the synthetic mixture by weightfrom reference standards4to obtain a final composition ap-proximating the following but accurately known wit
42、hin 60.07 %:Reference StandardLiquidVolumePercent inMixtureApproximateWeightin Gramsto Give5 mL of Mixture2-Methylpentane 7.2 0.2372,4-Dimethylpentane 9.4 0.318n-Octane 16.6 0.587Methylcyclopentane 7.1 0.267Methylcyclohexane 10.0 0.387cis-1,2-Dimethylcyclohexane 15.5 0.620Benzene 7.7 0.341Toluene 10
43、.0 0.436p-Xylene 16.5 0.714100.0 3.907Record the mass spectrum of the test mixture from m/e+32to 120 using the manipulative technique as described in 10.2.Compute 41/V, 43/V, and 77/V from the spectrum of thetest mixture and calculate the composition using these valuesand the inverse of 8.1. The cal
44、culated composition shouldagree with known concentrations within the following limits:PercentTotal paraffins 0.8Total cycloparaffins 1.3Total aromatics 0.7If the test mixture cannot be analyzed successfully, consid-eration should be given to interference, stability, sensitivity,resolution, sample ha
45、ndling, or ability of the analyst.8.3 BackgroundAfter pumping out the test mixture speci-fied in 10.2, scan the mass spectrum from m/e+40 to 100.Background peaks at 43 and 91 should be less than 0.1 % of thecorresponding peaks in the mixture spectrum. If both tests ofperformance are met, it may be p
46、resumed that the instrument issatisfactory for sample analysis.9. Sample Preparation9.1 Depentanize the sample in accordance with Test MethodD2001.9.2 Determine the olefin content of the depentanized samplein accordance with Test Methods D1319 or D875.10. Procedure10.1 Generally, mass spectrometers
47、are in continuous op-eration and should require no additional preparation beforeanalyzing samples. If the spectrometer has been turned on onlyrecently, check its operation according to the manufacturersinstructions to ensure stability before proceeding. Then makethe performance test (Section 8).10.2
48、 Obtaining the Mass SpectrumUsing a microburet5ora constant-volume pipet, introduce sufficient sample throughthe inlet system to give a pressure of 20 to 60 mtorr (2.7 to 8.0Pa). Record the amount of sample introduced and the finalpressure after expansion into the inlet system when a microbu-ret and
49、 manometer are used. Recharge the sample untilpressure readings that differ by 1 % or less are obtained.Attaining this pressure check means that a given microburet isbeing used at constant volume. When the pressure check isobtained, admit the sample to the mass spectrometer and recordthe mass spectrum of the sample from m/e+32 to 186.11. Calculation11.1 PeaksRead peak heights from the record of the massspectrum of the sample corresponding to m/e+ratios of 41, 43,55, 57, 67, 68, 69, 71, 77, 78, 79, 81, 82, 83, 84, 85, 86, 91, 92,95,
