1、Designation: D2425 04 (Reapproved 2009)D2425 17Standard Test Method forHydrocarbon Types in Middle Distillates by MassSpectrometry1This standard is issued under the fixed designation D2425; the number immediately following the designation indicates the year oforiginal adoption or, in the case of rev
2、ision, 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 Scope*1.1 This test method covers an analytical scheme using the mass spectrometer to determine the hy
3、drocarbon types present invirgin middle distillates 204204 C to 343C (400343 C (400 F to 650F)650 F) boiling range, 5 to 95 volume % 5 % to 95 %by volume as determined by Test Method D86. Samples with average carbon number value of paraffins between C12 and C16 andcontaining paraffins from C10 and C
4、18 can be analyzed. Eleven hydrocarbon types are determined. These include: paraffins,noncondensed cycloparaffins, condensed dicycloparaffins, condensed tricycloparaffins, alkylbenzenes, indans or tetralins, or both,CnH2n-10 (indenes, etc.), naphthalenes, CnH2n-14 (acenaphthenes, etc.),CnH2n-16 (ace
5、naphthylenes, etc.), and tricyclic aromatics.NOTE 1This test method was developed on Consolidated Electrodynamics Corporation Type 103 Mass Spectrometers.1.2 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are forinformation only.1.2.1 Exce
6、ptionThe inch-pound units given in parentheses are for information only.1.3 This standard does not purport to address all of the safety problems,concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appropriate safety safety, health, and healthe
7、nvironmental practices anddetermine the applicability of regulatory limitations prior to use. For a specific warning statement, see 10.1.1.4 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles
8、for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D86 Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric PressureD2549
9、 Test Method for Separation of Representative Aromatics and Nonaromatics Fractions of High-Boiling Oils by ElutionChromatography3. Terminology3.1 The summation of characteristic mass fragments are defined as follows:71 (paraffins) = total peak height of m/e+ 71 + 85.67 (mono or noncondensed polycycl
10、oparaffins, or both) = total peak height of m/e+ 67 + 68 + 69 + 81 + 82 + 83 + 96 + 97.123 (condensed dicycloparaffins) = total peak height of m/e + 123 + 124 + 137 + 138 + etc. up to 249 + 250.149 (condensed tricycloparaffins) = total peak height of m/e + 149 + 150 + 163 + 164 + etc. up to 247 + 24
11、8.91 (alkyl benzenes) = total peak height of m/e+ 91 + 92 + 105 + 106 + etc. up to 175 + 176.103 (indans or tetralins, or both) = total peak height of m/e+ 103 + 104 + 117 + 118 + etc. up to 187 + 188.115 (indenes or CnH2n-10, or both) = total peak height of m/e+ 115 + 116 + 129 + 130 + etc. up to 1
12、85 + 186.128 (naphthalene) = total peak height of m/e+ 128.141 (naphthalenes) = total peak height of m/e+ 141 + 142 + 155 + 156 + etc. up to 239 + 240.1 This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products Products, Liquid Fuels, and Lubricantsand is the direct resp
13、onsibility ofSubcommittee D02.04.0M on Mass Spectroscopy.Current edition approved Oct. 1, 2009Oct. 1, 2017. Published November 2009November 2017. Originally approved in 1965. Last previous edition approved in 20042009as D2425D2425 04 (2009).04. DOI: 10.1520/D2425-04R09.10.1520/D2425-17.2 For referen
14、cedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the
15、user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard
16、 as published by ASTM is to be considered the official document.*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 States1153 (acenaphthenes or C nH2n-14, or both) = total peak he
17、ight of m/e+ 153 + 154 + 167 + 168 + etc. up to 251 + 252.151 (acenaphthylenes or C nH2n-16, or both) = total peak height of m/e+ 151 + 152 + 165 + 166 + etc. up to 249 + 250.177 (tricyclic aromatics) = total peak height of m/e+ 177 + 178 + 191 + 192 + etc. up to 247 + 248.4. Summary of Test Method4
18、.1 Samples are separated into saturate and aromatic fractions by Test Method D2549, and each fraction is analyzed by massspectrometry. The analysis is based on the summation of characteristic mass fragments to determine the concentration ofhydrocarbon types. The average carbon numbers of the hydroca
19、rbon types are estimated from spectral data. Calculations are madefrom calibration data dependent upon the average carbon number of the hydrocarbon types. The results of each fraction aremathematically combined according to their mass fractions as determined by the separation procedure. Results are
20、expressed inmass percent.NOTE 2Test Method D2549 is presently applicable only to samples having 5 % points of 232C (450F)232 C (450 F) or greater.5. Significance and Use5.1 A knowledge of the hydrocarbon composition of process streams and petroleum products boiling within the range of400400 F to 650
21、F (204650 F (204 C to 343C)343 C) is useful in following the effect of changes in process variables,diagnosing the source of plant upsets, and in evaluating the effect of changes in composition on product performance properties.6. Interferences6.1 Nonhydrocarbon types, such as sulfur and nitrogen-co
22、ntaining compounds, are not included in the matrices for this testmethod. If these nonhydrocarbon types are present to any large extent, (for example, mass percent sulfur 0.25) they will interferewith the spectral peaks used for the hydrocarbon-type calculation.7. Apparatus7.1 Mass SpectrometerThe s
23、uitability of the mass spectrometer to be used with this method of analysis shall be proven byperformance tests described herein.7.2 Sample Inlet SystemAny inlet system permitting the introduction of the sample without loss, contamination, or change incomposition. To fulfill these requirements it wi
24、ll be necessary to maintain the system at an elevated temperature in the range of125125 C to 325C325 C and to provide an appropriate sampling device.7.3 Microburet or Constant-Volume Pipet.8. Calibration8.1 Calibration coefficients are attached which can be used directly provided:8.1.1 Repeller sett
25、ings are adjusted to maximize the m/e+ 226 ion of n-hexadecane.8.1.2 A magnetic field is used that will permit scanning from m/e+ 40 to 292.8.1.3 An ionization voltage of 70 eV and ionizing currents in the range 1010 A to 70 A 70 A are used.NOTE 3The calibration coefficients were obtained for ion so
26、urce conditions such that the67/71 ratio for n-hexadecane was 0.26/1.The cooperativestudy of this test method indicated an acceptable range for this ratio between 0.2/1 to 0.30/1.NOTE 4Users of instruments other than Consolidated Electrodynamics Corporation Type 103 Mass Spectrometers may have to de
27、velop their ownoperating parameters and calibration data.9. Performance Test9.1 Generally, mass spectrometers are in continuous operation and should require no additional preparation before analyzingsamples. If the spectrometer has been turned on only recently, it will be necessary to check its oper
28、ation in accordance with thismethod and instructions of the manufacturer to ensure stability before proceeding.9.2 Mass Spectral BackgroundSamples in the carbon number range C10 to C18 should pump out so that less than 0.1 % ofthe two largest peaks remain. For example, background peaks from a satura
29、te fraction at m/e+ 69 and 71 should be reduced to lessthan 0.1 % of the corresponding peaks in the mixture spectrum after a normal pump out time of 22 min to 5 min.10. Mass Spectrometric Procedure10.1 Obtaining the Mass Spectrum for Each Chromatographic FractionUsing a microburet or constant-volume
30、 pipet,introduce sufficient sample through the inlet sample to give a pressure of 2 to 4 Pa (15 to 30 mtorr) 2 Pa to 4 Pa (15 mtorr to30 mtorr) in the inlet reservoir. (WarningWarningHydrocarbonHydrocarbon samples of this boiling range are combustible.)Record the mass spectrum of the sample from m/e
31、+ 40 to 292 using the instrument conditions outlined in 8.1.1 8.1.3.D2425 17211. Calculations and Report11.1 Aromatic FractionRead peak heights from the record mass spectrum corresponding to m/e+ ratios of 67 to 69, 71, 81 to83, 85, 91, 92, 96, 97, 103 to 106, 115 to 120, 128 to 134, 141 to 148, 151
32、 to 162, 165 to 198, 203 to 212, 217 to 226, 231 to240, 245, 246, 247 to 252.Find:(71571185 (1)(67567168169181182183196197 (2)(915(N50N5691114N!192114N!# (3)(915(N50N5691114N!192114N!# (3)(1035(N50N56 103114N!1104114N!# (4)(1035(N50N56 103114N!1104114N!# (4)(1155(N50N55 115114N!1116114N!# (5)(1155(N
33、50N55 115114N!1116114N!# (5)(1415(N50N57 141114N!1142114N!# (6)(1415(N50N57 141114N!1142114N!# (6)(1535(N50N57 153114N!1154114N!# (7)(1535(N50N57 153114N!1154114N!# (7)(1515(N50N57 151114N!1152114N!# (8)(1515(N50N57 151114N!1152114N!# (8)(1775(N50N55 177114N!1178114N!# (9)(1775(N50N55 177114N!117811
34、4N!# (9)11.2 Calculate the mole fraction at each carbon number of the alkylbenzenes for n = 10 to n = 18 as follows:n 5P m 2Pm21K1!#/K2 (10)where:where:n = mole fraction of each alkylbenzene as represented by n which indicates the number of carbons in each molecularspecies.m = molecular weight of th
35、e alkylbenzene being calculated,TABLE 1 Parent Ion Isotope Factors and Mole SensitivitiesCarbon No. m/e IsotopeFactor, K1MoleSensitivity, K2Alkylbenzenes10 134 0.1101 8511 148 0.1212 6312 162 0.1323 6013 176 0.1434 5714 190 0.1545 5415 204 0.1656 5116 218 0.1767 4817 232 0.1878 4518 246 0.1989 42L1
36、L2Naphthalenes11 142 0.1201 19412 156 0.1314 16613 170 0.1425 15014 184 0.1536 15015 198 0.1647 15016 212 0.1758 15017 226 0.1871 15018 240 0.1982 150D2425 173m 1 = molecular weight minus 1,P = polyisotopic mixture peak at m,m 1,K1 = isotopic correction factor (see Table 1), andK2 = mole sensitivity
37、 for n (see Table 1).NOTE 5This step of calculation assumes no mass spectral pattern contributions from other hydrocarbon types to the parent and parent-1 peaks of thealkylbenzenes. Selection of the lowest carbon number 10 is based upon the fact that C9 alkylbenzenes boil below 204C (400F) and their
38、 concentrationcan be considered negligible.11.3 Find the average carbon number of the alkylbenzenes, A, in the aromatic fraction as follows:A 5(n510n518n 3n!/(n510n518n! (11)A 5(n510n518n 3n!/(n510n518n! (11)11.4 Calculate the mole fraction at each carbon number of the naphthalenes for n = 11 to n =
39、 18 as follows:xn 5Pm 2P m21L1!#/L2 (12)where:where:xn = mole fraction of each naphthalene as represented by n which indicates the number of carbons in each molecular species,m = molecular weight of the naphthalenes being calculated,m 1 = molecular weight minus 1,P = polyisotopic mixture peak at m,m
40、 1,L1 = isotopic correction factor (see Table 1), andL2 = mole sensitivity for n (see Table 1).NOTE 6This step of calculation assumes no mass spectral pattern contributions to the parent and parent-1 peaks of the naphthalenes. Theconcentration of naphthalene itself at a molecular weight of 128 shall
41、 be determined separately from the polyisotopic peak at m/e + 128 in the matrixcalculation. The average carbon number for the naphthalenes shall be calculated from carbon number 11 (molecular weight 142) to 18 (molecular weight240).11.5 Find the average carbon number of the naphthalenes, B, in the a
42、romatic fraction as follows:B 5(n511n518nxn!/(n511n518xn! (13)11.6 Selection of pattern and sensitivity data for matrix carbon number of the types present. The average carbon number of theparaffins and cycloparaffins (71 and 67, respectively) are related to the calculated average carbon of the alkyl
43、benzenes (11.3),as shown in Table 2. Both 71 and 67 are included in the aromatic fraction matrix to check on possible overlap in the separation.The other types present, represented by s 103, 115, 153, and 151, are usually relatively low in concentration so that their parentions are affected by other
44、 types present. The calculation of their average carbon number is not straight forward. Therefore, theiraverage carbon numbers are estimated by inspection of the aromatic spectrum. Generally, their average carbon numbers may betaken to be equivalent to that of the naphthalenes, or to the closest who
45、le number thereof, as calculated in 11.5. The average carbonnumber of tricyclic aromatics 177 has to be at least C14 and in full boiling range middle distillates C14 may be used to representthe 177 types carbon number. From the calculated and estimated average carbon numbers of the hydrocarbon types
46、, a matrix forthe aromatic fraction is set up using the calibration data given in Table 3. A sample matrix for the aromatic fraction is shown inTable 4. The matrix calculations consist in solving a set of simultaneous linear equations. The pattern coefficients are listed in Table3. The constants are
47、 the values determined from the mass spectrum. Second approximation solutions are of sufficient accuracy.If many analyses are performed using the same type of a matrix, the matrix may be inverted for simpler, more rapid deskcalculation. Matrices may also be programmed for automatic computer operatio
48、ns. The results of matrix calculations are convertedto mass fractions by dividing by mass sensitivity. The mass fractions are normalized to the mass percent of the aromatic fraction,as determined by the separation procedure.11.7 Saturate FractionRead peak at heights from the record of the mass spect
49、rum corresponding to m/e+ ratios of 67 to 69,71, 81 to 83, 85, 91, 92, 96, 97, 105, 106, 119, 120, 123, 124, 133, 134, 137, 138, 147 to 152, 161 to 166, 175 to 180, 191 to 194,205 to 208, 219 to 222, 233 to 236, 247 to 250.TABLE 2 Relationship Between Average Carbon Numbers ofAlkylbenzenes, Paraffins, and CycloparaffinsAlkylbenzenes Paraffin and CycloparaffinAverage Carbon No. Average Carbon No.10 1111 1212 1313
