1、Designation: D2789 95 (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
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、, 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,orbyTestMeth
4、od 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 doe
5、s 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 Stan
6、dards:2D86 Test Method for Distillation of Petroleum Products atAtmospheric PressureD875 Method for Calculating of Olefins and Aromatics inPetroleum Distillates from Bromine Number and AcidAbsorption3D1319 Test Method for Hydrocarbon Types in LiquidPetroleum Products by Fluorescent Indicator Adsorpt
7、ionD2001 Test Method for Depentanization of Gasoline andNaphthasD2002 Practice for Isolation of Representative SaturatesFraction from Low-Olefinic Petroleum Naphthas33. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 The summations of characteristic mass fragments aredefined as f
8、ollows (equations are identical to those in 11.1):(43 paraffins!5total peak height of m/e143 1 57 1 71 1 85 1 99.(1)(41 monocycloparaffins!5total peak height of m/e141 1 55 1 691 83 1 97. (2)(67 dicycloparaffins!5total peak height of m/e167 1 68 1 81 1 821 95 1 96. (3)(77 alkylbenzenes!5total peak h
9、eight of m/e177 1 78 1 79 1 911 92 1 105 1 106 1 119 1 120 1 133 1 134 1 147 1 148 1 1611 162. (4)(103 indans and tetralins!5total peak height of m/e1103 1 1041 117 1 118 1 131 1 132 1 145 1 146 1 159 1 160. (5)(128 naphthalenes!5total peak height of m/e1128 1 141 6 1421 155 1 156. (6)T 5 total ion
10、intensity 5 (41 1 (43 1 (67 1 (77 1 (103 1 (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
11、 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 fromspectral data. Calculations are made from calibration datawhich are dependent upon the average numbe
12、r 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 operating1This test method
13、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 D27899
14、5(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.3Withdrawn. The last approve
15、d version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.conditions, diagnosing process upsets, blending finished prod-ucts and in evaluating the relationship between composit
16、ionand performance 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
17、 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 t
18、he applicability of thecalibration data in Table 1. If necessary, individual laboratories shoulddevelop their own calibration data using the blends described in Table 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 ManometerAmanometer suitable for direct reading
20、inthe 0 to 100-mtorr (0 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-dimethylp
21、entane, n-octane, methylcyclo-pentane, methylcyclohexane, cis-1,2-dimethylcyclohexane,benzene, toluene, and p-xylene (WarningExtremely flam-mable liquids. Benzene is a poison, carcinogen, and is harmfulor fatal if swallowed.). Only reagent grade chemicals conform-ing to the specifications of the Com
22、mittee on AnalyticalTABLE 1 Calibration Data(43/T (41/T (67/T (77/T (103/T (128/T ReferenceAParaffins:C60.6949 0.3025 0.0019 0.0006 . . (1)C70.7379 0.2583 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)
23、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 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
24、.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 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:C
25、90.0144 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:C10C110.01210.07020.00370.01400.00080.00110.05810.01720.00650.00180.91880.8957(10)(11)AReferences to source of calibration data:(1) National cooperati
26、ve 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. 448, 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
27、 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 API 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
28、. 991.(12) National cooperative by letter of Oct. 11, 1967.(13) Proposed Method of Test for Hydrocarbon Types in Low Olefinic Gasoline by Mass Spectrometry; Appendix VII D2-1958.D2789 95 (2011)2Reagents of the American Chemical Society,4National Insti-tute of Standards and Technology (NIST) standard
29、 hydrocar-bon samples, or other hydrocarbons of equal purity should beused.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
30、 the calibration 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 desc
31、ribed in 8.2. Constructan inverse from the averaged coefficients.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals
32、, 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-Alkyl-benzenesComponent (Volume Percent) Paraffins
33、Cyclo-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 3 . .Cyclohexane . 46 . 2,6-Dimethylheptane 12 . .
34、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-Methylhexane 16 . . n-Propylcyclohexane . 1 .2,2-D
35、imethylpentane 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 . 57 . 1-Methyl-t-3-ethylcyclohexane . 8 .Ethylcyclo
36、pentane . 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-trimethylcyclohexane . 3 .Toluene . . 100 1,t-2,c-3-trimethylcyclohexan
37、e . 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-Methylheptane 8 . . 1,c-2-Diethylcyclopentane . 12 .3-Ethy
38、lhexane 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-ethylbenzene . . 191,t-2-Dimethylcyclohexane . 18 . 1-Methyl-
39、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-2,c-3-Trimethylcyclopentane . 9 .1,t-2,c-4-Trimethyl
40、cyclopentane . 5 .Ethylbenzene . . 10p-Xylene . . 23m-Xylene . . 46o-Xylene . . 21D2789 95 (2011)3NOTE 4The volume, V, ordinarily is expressed as microlitres.NOTE 5A desk calculator frequently is used for the calculation of 8.1and in such cases small inverse terms can be undesirable. If necessary, i
41、tis permissible 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 kn
42、own within 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 0.341Tol
43、uene 10.0 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.
44、1. The calculated composition shouldagree with known concentrations within the following limits:PercentTotal paraffins 60.8Total cycloparaffins 61.3Total aromatics 60.7If the test mixture cannot be analyzed successfully, consid-eration should be given to interference, stability, sensitivity,resoluti
45、on, sample handling, 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
46、, it may be presumed 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 s
47、pectrometers 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 (Se
48、ction 8).10.2 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 mi
49、crobu-ret and 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, 96,
