ASTM D2425-23

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it 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 version
of the standard as published by ASTM is to be considered the official document.
Designation: D2425 − 21 D2425 − 23
Standard Test Method for
Hydrocarbon Types in Middle Distillates by Mass
Spectrometry
This standard is issued under the fixed designation D2425; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This test method covers an analytical scheme using the mass spectrometer to determine the hydrocarbon types present in
conventional and synthesized hydrocarbons that have a boiling range of 160 °C to 343 °C (320 °F to 650 °F), 5 % to 95 % by
volume as determined by Test Method D86. Samples with average carbon number value of paraffins between C and C and
12 16
containing paraffins from C and C can be analyzed. Eleven hydrocarbon types are determined. These include: paraffins,
10 18
noncondensed cycloparaffins, condensed dicycloparaffins, condensed tricycloparaffins, alkylbenzenes, indans or tetralins, or both,
C H (indenes, etc.), naphthalenes, C H (acenaphthenes, etc.),
n 2n-10 n 2n-14
C H (acenaphthylenes, etc.), and tricyclic aromatics.
n 2n-16
NOTE 1—This test method was developed on Consolidated Electrodynamics Corporation Type 103 Mass Spectrometers. Operating parameters for users
with a Quadrupole Mass Spectrometer are provided.
1.2 This test method is intended for use with full boiling range products that contain no significant olefin content.
Biodiesel (FAME components) could interfere with the separation of the sample and the characteristic mass fragments of FAME
compounds are not defined in the procedure.
Hydrocarbons containing tertiary carbon fragments, sometimes found in synthetic aviation fuels, will interfere with the
characteristic mass fragments of paraffins and result in a false, elevated cycloparaffin content.
NOTE 2—“No significant olefin content” for this method means <2.0 % by volume by Test Method D1319.
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for
information only and are not considered standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use. For a specific warning statement, see 11.1.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.04.0M on Mass Spectrometry.
Current edition approved June 1, 2021Dec. 1, 2023. Published June 2021January 2024. Originally approved in 1965. Last previous edition approved in 20192021 as
D2425 – 19.D2425 – 21. DOI: 10.1520/D2425-21.10.1520/D2425-23.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2425 − 23
2. Referenced Documents
2.1 ASTM Standards:
D86 Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure
D1319 Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorption
D2549 Test Method for Separation of Representative Aromatics and Nonaromatics Fractions of High-Boiling Oils by Elution
Chromatography
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
D6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and
Lubricants
D6379 Test Method for Determination of Aromatic Hydrocarbon Types in Aviation Fuels and Petroleum Distillates—High
Performance Liquid Chromatography Method with Refractive Index Detection
E355 Practice for Gas Chromatography Terms and Relationships
3. Terminology
3.1 Definitions:
3.1.1 This test method makes reference to many common gas chromatographic procedures and terms. Detailed definitions of these
can be found in Practice E355 and Terminology D4175.
3.2 Definitions:Definitions of Terms Specific to This Standard:
3.2.1 conventional hydrocarbons, n—hydrocarbons derived from the following conventional sources: crude oil, natural gas liquid
condensates, heavy oil, shale oil, and oil sands.
3.2.2 synthesized hydrocarbons, n—hydrocarbons derived from alternative sources such as coal, natural gas, biomass, and
hydrogenated fats and oils by processes such as gasification, Fischer-Tropsch synthesis, and hydroprocessing.
4. Summary of Test Method
4.1 Samples are separated into saturate and aromatic fractions by liquid chromatography, and each fraction is analyzed by mass
spectrometry. The analysis is based on the summation of characteristic mass fragments to determine the concentration of
hydrocarbon types.
4.2 The summation of characteristic mass fragments are defined as follows:
+
∑71 (paraffins) = total peak height of m/e 71 + 85.
+
∑67 (mono or noncondensed polycycloparaffins, 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 + 248.
+
∑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 C H , or both) = total peak height of m/e 115 + 116 + 129 + 130 + ··· etc. up to 185 + 186.
n 2n-10
+
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.
+
∑153 (acenaphthenes or C H , or both) = total peak height of m/e 153 + 154 + 167 + 168 + ··· etc. up to 251 + 252.
n 2n-14
+
∑151 (acenaphthylenes or C H , or both) = total peak height of m/e 151 + 152 + 165 + 166 + ··· etc. up to 249 + 250.
n 2n-16
+
∑177 (tricyclic aromatics) = total peak height of m/e 177 + 178 + 191 + 192 + ··· etc. up to 247 + 248.
4.3 The average carbon numbers of the hydrocarbon types are estimated from spectral data. Calculations are made from calibration
data dependent upon the average carbon number of the hydrocarbon types. The results of each fraction are mathematically
combined according to their mass fractions as determined by the separation procedure. Results are expressed in mass percent.
5. Significance and Use
5.1 A knowledge of the hydrocarbon composition of process streams and petroleum products boiling within the range of 160 °C
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
D2425 − 23
to 343 °C (320 °F to 650 °F) 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.
5.2 A test method to determine total cycloparafins and low level aromatic content is necessary to meet specifications for aviation
turbine fuel containing synthesized hydrocarbons.
6. Interferences
6.1 Nonhydrocarbon types, such as sulfur and nitrogen-containing compounds, are not included in the matrices for this test
method. If these nonhydrocarbon types are present to any large extent, (for example, mass percent sulfur >0.25) they will interfere
with the spectral peaks used for the hydrocarbon-type calculation.
7. Sample Separation
7.1 Sample is to be separated into saturate and aromatic fractions. Liquid chromatography procedures based on Test Methods
D2549, D1319, and D6379 have been used.
NOTE 3—Test Method D2549 is presently applicable only to samples having 5 % points of 232 °C (450 °F) or greater. Guidance on using Test Methods
D1319 and D6379 is provided in the Annexes.
PROCEDURE A—MAGNETIC SECTOR SPECTROMETER
8. Apparatus
8.1 Mass Spectrometer—The suitability of the mass spectrometer to be used with this method of analysis shall be proven by
performance tests described herein.
8.2 Sample Inlet System—Any inlet system permitting the introduction of the sample without loss, contamination, or change in
composition. To fulfill these requirements it will be necessary to maintain the system at an elevated temperature in the range of
125 °C to 325 °C and to provide an appropriate sampling device.
8.3 Microburet or Constant-Volume Pipet.
9. Calibration
9.1 Calibration coefficients are attached which can be used directly provided:
+
9.1.1 Repeller settings are adjusted to maximize the m/e 226 ion of n-hexadecane.
+
9.1.2 A magnetic field is used that will permit scanning from m/e 40 to 292.
9.1.3 An ionization voltage of 70 eV and ionizing currents in the range 10 μA to 70 μA are used.
NOTE 4—The calibration coefficients were obtained for ion source conditions such that the ∑67/∑71 ratio for n-hexadecane was 0.26/1. The cooperative
study of this test method indicated an acceptable range for this ∑ ratio between 0.2/1 to 0.30/1.
10. Performance Test
10.1 Generally, mass spectrometers are in continuous operation and should require no additional preparation before analyzing
samples. If the spectrometer has been turned on only recently, it will be necessary to check its operation in accordance with this
method and instructions of the manufacturer to ensure stability before proceeding.
10.2 Mass Spectral Background—Samples in the carbon number range C to C should pump out so that less than 0.1 % of the
10 18
+
two largest peaks remain. For example, background peaks from a saturate fraction at m/e 69 and 71 should be reduced to less than
0.1 % of the corresponding peaks in the mixture spectrum after a normal pump out time of 2 min to 5 min.
D2425 − 23
11. Mass Spectrometric Procedure
11.1 Obtaining the Mass Spectrum for Each Chromatographic Fraction—Using a microburet or constant-volume pipet, introduce
sufficient sample through the inlet sample to give a pressure of 2 Pa to 4 Pa (15 mtorr to 30 mtorr) in the inlet reservoir.
+
(Warning—Hydrocarbon samples of this boiling range are combustible.) Record the mass spectrum of the sample from m/e 40
to 292 using the instrument conditions outlined in 9.1.1 – 9.1.3.
PROCEDURE B—QUADRUPOLE SPECTROMETER
12. Apparatus
12.1 Mass Spectrometer—Mass spectrometers provided with a quadrupole as ion separator and use electron impact at 70 ev have
been used.
12.2 Sample Inlet System—Any inlet system permitting the introduction of the sample without loss, contamination, or change in
composition. Separation of components is not required.
12.2.1 For sample fractions that do not contain solvents:
12.2.1.1 The inlet to introduce the sample into the detector can be an all glass inlet system (also known as AGIS) connected to
the GC inlet and interfaced with the mass spectrometer with uncoated tubing. The inlet system is installed in a gas chromatograph
and heated at 300 °C, isothermal.
12.2.1.2 Gas chromatography using a boiling point column.
12.2.2 For sample fractions that contain solvents, gas chromatography using a boiling point column should be used to isolate the
solvent.
NOTE 5—Appendix X2 provides additional information on chromatography options for samples with or without solvents.
12.2.3 Split ratio should be adjusted to prevent detector overload.
13. Calibration
13.1 Mass calibration is performed using PerFluoroTriButylAmine (PFTBA) which contains the masses 69, 131, 219, 414, and
502. An ionization voltage of 70 ev is used.
13.2 Tune the spectrometer using the tune file recommended by the manufacturer. Typically, the masses of 69, 219, 502 are used
for tuning with 219 being the ion for repeller maximum. Ensure that none of the masses are saturated.
13.3 It is possible to check the tuning by introducing n-hexadecane and verifying that the sum of the ∑67/∑71 = 0.2 – 0.3. Verify
that the sum elements are those shown in 15.1, Eq 1 and Eq 2.
14. Mass Spectrometric Procedure
14.1 Obtaining the Mass Spectrum for Each Chromatographic Fraction—Using an automated sampling system or manual
+
injection, inject an appropriate amount of each sample fraction. Record the mass spectrum of the sample from m/e 50 to 300.
15. Calculations and Report
NOTE 6—A guideline for the calculations is available in Appendix X1.
+
15.1 Aromatic Fraction—Read peak heights from the record mass spectrum corresponding to m/e ratios of 67 to 69, 71, 81 to
83, 85, 91, 92, 96, 97, 103 to 106, 115 to 120, 128 to 134, 141 to 148, 151 to 162, 165 to 198, 203 to 212, 217 to 226, 231 to
240, 245, 246, 247 to 252.
Find:
D2425 − 23
TABLE 1 Parent Ion Isotope Factors and Mole Sensitivities
Isotope Mole
Carbon No. m/e
Factor, K Sensitivity, K
1 2
Alkylbenzenes
10 134 0.1101 85
11 148 0.1212 63
12 162 0.1323 60
13 176 0.1434 57
14 190 0.1545 54
15 204 0.1656 51
16 218 0.1767 48
17 232 0.1878 45
18 246 0.1989 42
L L
1 2
Naphthalenes
11 142 0.1201 194
12 156 0.1314 166
13 170 0.1425 150
14 184 0.1536 150
15 198 0.1647 150
16 212 0.1758 150
17 226 0.1871 150
18 240 0.1982 150
71 5 71185 (1)
(
67 5 67168169181182183196197 (2)
(
N56
91 5 91114N 1 92114N (3)
@~ ! ~ !#
( ( N50
N56
103 5 @ 103114N 1 104114N # (4)
~ ! ~ !
( ( N50
N55
115 5 @~115114N!1~116114N!# (5)
( ( N50
N57
141 5 141114N 1 142114N (6)
@~ ! ~ !#
( ( N50
N57
153 5 153114N 1 154114N (7)
@~ ! ~ !#
( ( N50
N57
151 5 @~151114N!1~152114N!# (8)
( ( N50
N55
177 5 177114N 1 178114N (9)
@~ ! ~ !#
( ( N50
15.2 Calculate the mole fraction at each carbon number of the alkylbenzenes for n = 10 to n = 18 as follows:
μ 5 P 2 P K /K (10)
~ !
@ #
n m m21 1 2
where:
μ = mole fraction of each alkylbenzene as represented by n which indicates the number of carbons in each molecular
n
species,
m = molecular weight of the alkylbenzene being calculated,
m − 1 = molecular weight minus 1,
P = polyisotopic mixture peak at m,m − 1,
K = isotopic correction factor (see Table 1), and
K = mole sensitivity for n (see Table 1).
NOTE 7—This step of calculation assumes no mass spectral pattern contributions from other hydrocarbon types to the parent and parent-1 peaks of the
alkylbenzenes. Selection of the lowest carbon number 10 is based upon the fact that C alkylbenzenes boil below 204 °C (400 °F) and their concentration
can be considered negligible.
15.3 Find the average carbon number of the alkylbenzenes, A, in the aromatic fraction as follows:
n518 n518
A 5 n ×μ / μ (11)
~ ! ~ !
n n
(n510 (n510
15.4 Calculate the mole fraction at each carbon number of the naphthalenes for n = 11 to n = 18 as follows:
x 5 P 2 P L /L (12)
@ ~ !#
n m m21 1 2
D2425 − 23
where:
x = mole fraction of each naphthalene as represented by n which indicates the number of carbons in each molecular species,
n
m = molecular weight of the naphthalenes being calculated,
m − 1 = molecular weight minus 1,
P = polyisotopic mixture peak at m,m − 1,
L = isotopic correction factor (see Table 1), and
L = mole sensitivity for n (see Table 1).
NOTE 8—This step of calculation assumes no mass spectral pattern contributions to the parent and parent-1 peaks of the naphthalenes. The concentration
+
of naphthalene itself at a molecular weight of 128 shall be determined separately from the polyisotopic peak at m/e 128 in the matrix calculation. The
average carbon number for the naphthalenes shall be calculated from carbon number 11 (molecular weight 142) to 18 (molecular weight 240).
15.5 Find the average carbon number of the naphthalenes, B, in the aromatic fraction as follows:
n518 n518
B 5 nx / x (13)
~ ! ~ !
(n511 n (n511 n
15.6 Selection of pattern and sensitivity data for matrix carbon number of the types present. The average carbon number of the
paraffins and cycloparaffins (∑71 and ∑67, respectively) are related to the calculated average carbon of the alkylbenzenes (15.3),
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 parent
ions are affected by other types present. The calculation of their average carbon number is not straight forward. Therefore, their
average carbon numbers are estimated by inspection of the aromatic spectrum. Generally, their average carbon numbers may be
taken to be equivalent to that of the naphthalenes, or to the closest whole number thereof, as calculated in 15.5. The average carbon
number of tricyclic aromatics ∑177 has to be at least C and in full boiling range middle distillates C may be used to represent
14 14
the ∑177 types carbon number. From the calculated and estimated average carbon numbers of the hydrocarbon types, a matrix for
the aromatic fraction is set up using the calibration data given in Table 3. A sample matrix for the aromatic fraction is shown in
Table 4. The matrix calculations consist in solving a set of simultaneous linear equations. The pattern coefficients are listed in Table
3. The constants are 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 desk
calculation. Matrices may also be programmed for automatic computer operations. The results of matrix calculations are converted
to 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.
+
15.7 Saturate Fraction—Read peak at heights from the record of the mass spectrum 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.
Find:
71 5 71185 (14)
(
67 5 67168169181182183196197 (15)
(
N59
123 5 123114N 1 124114N (16)
@~ ! ~ !#
( ( N50
N57
149 5 149114N 1 150114N (17)
@~ ! ~ !#
( ( N50
N56
91 5 @~91114N!1~92114N!# (18)
( ( N50
15.8 Selection of the pattern and sensitivity data for matrix calculation is dependent upon the average carbon number of the types
present. The average carbon number of the paraffins and cycloparaffin types (∑’s 71, 69, 123, and 149), are related to the calculated
TABLE 2 Relationship Between Average Carbon Numbers of
Alkylbenzenes, Paraffins, and Cycloparaffins
Alkylbenzenes Paraffin and Cycloparaffin
Average Carbon No. Average Carbon No.
10 11
11 12
12 13
13 15 (14.5)
14 16 (15.5)
D2425 − 23
TABLE 3 Patterns and Sensitivities for Middle Distillates
Hydrocarbon
Paraffins Noncondensed Cycloparaffins Condensed Dicycloparaffins Condensed Tricycloparaffins
Type
Carbon No. 12 13 14.5 15.5 12 13 14.5 15.5 13 14.5 15.5 13 14.5 15.5
Peaks read:
^71 100 100 100 100 4 4 6 6 2 1.1 1.5 1 1 2
^67 19 21 23 26 100 100 100 100 160 130 150 175 170 150
^123 . . 0.1 0.2 1 1 1 3 100 100 100 26 10 20
^149 . . . . . . . . 0.2 5 8 100 100 100
^91 to 176 0.4 0.4 0.4 0.4 . . 0.2 3 4 4 5 15 15 20
^103 to 188 . . . . . . . . . . . 1 . 3
^115 to 186 0.5 . . . 1 1 1 1 0.5 . . . . .
^128 pk . . . . . . . . . . . . . .
^141 9 9 10 12 . . 2 0.3 0.2 . . 0.1 0.1 0.4
^153 . . . . 1 2 2 2 . . . . . .
^151 . . . . 1 5 7 10 . . . . . .
^177 . . . . . . 2 2 . . . . . .
...
Sensitivity:
Mole 148 170 192 238 302 347 416 439 220 268 298 220 268 298
Volume 66 70 74 81 145 153 165 170 107 137 117 118 150 127
Mass 87 92 97 104 180 191 204 209 122 156 134 124 158 135
Hydrocarbon Alkylbenzenes Indans or Tetralins, or Both Indenes or C H , Naphthalenes
n 2n-10
Type or Both
Carbon No. 11 12 13 14 10 11 12 13 10 13 10 11 12 13
Peaks read:
^71 0.3 0.3 0.4 0.5 0.2 0.4 0.4 1 0.3 1.7 0.5 5.2 1.5 2
^67 0.7 0.7 2 3 0.6 1 1 2 0.3 6.0 0.8 1.2 1.5 2
^123 0.1 0.1 0.2 0.3 . 0.1 1 2 0.4 4.8 0.2 0.5 7.8 4
^149 1.3 1 1.5 2 . 0.1 0.2 0.3 . 0.9 . 0.1 0.7 0.5
^91 to 176 100 100 100 100 15 to 18 17 15 0.6 6.2 0.1 0.9 1 1
A,B
^103 to 188 9 10 10 9 100 100 100 100 1.5 20.3 0.6 0.1 0.1 0.1
^115 to 186 4.4 4.5 5 5 20 to 28 25 25 100 100 11.4 23 19 18
A,B
^128 pk 0.7 1 1 1 3 5.4 7 . 15 13 100 0.7 5.6 5.6
^141 . . . . . 1.0 2.5 . . 28 . 100 100 100
^153 . . . . . . . . . 6.1 . . 8 10
^151 . . . . . . . . . 4.5 . . 7 7
^177 . . . . . . . . . 0.6 . . . .
Sensitivity:
Mole 450 450 450 450 380 420 420 420 410 372 236 360 380 380
Volume 265 242 222 206 280 276 250 227 307 198 211 259 248 226
Mass 304 278 256 237 288 288 263 241 315 200 184 254 244 224
Acenaph-
Acenaph-
Hydrocarbon thenes or Tricyclic
thylenes or Characteristic Mass Groupings
Type C H -14, Aromatics
n 2n
C H -16
n 2n
or Both
Carbon No. 12 13 12 13 14 Peaks Read Hydrocarbon Types
Peaks read:
^71 1 1 1 1 0.6
^67 0.3 2 1 5 0.7 ^71 = 71, 85 paraffins
^91 to 176 0.1 5 1 3 18 ^67 = 67, 68, 69, 81, 82, 83, 96, 97 cycloparaffins, mono or noncondensed
^103 to 188 . 3 0.2 3 1.5 cycloparaffins
^115 to 186 0.8 0.8 0.3 2.7 1.0 ^123 = 123, 134, 137, 138 up to 249, 250 condensed dicycloparaffins
^128 pk 1 0.7 0.2 0.1 0.8 ^149 = 149, 150, 163, 164 up to 247, 248 condensed tricycloparaffins
^141 8 10 1 . 0.3 ^91 = 91, 92, 105, 106 up to 175, 176 alkylbenzenes
^153 100 100 17 15 3.5 ^103 = 103, 104, 117, 118, up to 187, 188 indan or tetrains, or both
^151 27 20 100 100 30 ^115 = 115, 116, 129, 130 up to 185, 186 C H (indenes, etc.)
n 2n-10
^177 . 4 . 15 100 ^128 = poly 128 pk naphthalene
Sensitivity: ^141 = 141, 142, 155, 156 up to 239, 240 naphthalenes
Mole 330 330 340 340 365 ^153 = 153, 154, 167, 168 up to 251, 252 C H (acenaphthenes, etc.)
n 2n-14
Volume 218 198 199 187 211 ^151 = 151, 152, 165, 166 up to 249, 250 C H (acenaphthylenes, etc.)
n 2n-16
Mass 214 196 224 205 205 ^177 = 177, 178, 191, 192 up to 247, 248 tricyclic aromatics
A
= methyl indans.
B
tetralins.
D2425 − 23
TABLE 4 Aromatic Concentration Matrix
Indans Acenaph- Acenaph-
Hydrocarbon Alkylben- Tricyclic
Paraffins Cycloparaffins and Indenes Naphthalene Naphthalenes thenes thylenes
Type zenes Aromatics
Tetralins C H C H
n 2n-14 n 2n-16
Carbon No. 15.5 15.5 14 13 13 10 13 13 13 14
Peaks read:
^71 100 6 0.5 1 1.7 0.5 2 1 1 0.6
^67 26 100 3 2 6 0.8 2 2 5 0.7
^91 0.4 3 100 15 6.2 0.1 1 5 3 18
^103 . 2 9 100 20.3 0.6 0.1 3 3 1.5
^115 . 1 5 25 100 11.4 18 0.8 2.7 1
^128 pk . . 1 3 13 100 5.6 0.7 0.1 0.8
^141 12 0.3 . . 28 . 100 10 . 0.3
^153 . 2 . . 6.1 . 10 100 15 3.5
^151 . 10 . . 4.5 . 7 20 100 30
^177 . 2 . . 0.6 . . 4 15 100
Sensitivity:
Mole 238 439 450 420 372 236 380 330 340 365
Volume 81 170 206 227 198 211 226 198 187 211
Weight 105 209 237 241 200 184 224 196 205 205
average carbon number of the alkylbenzenes of the aromatic fraction (15.3), as shown in Table 2. The ∑91 is included in the
saturate fraction as a check on the efficiency of the separation procedure. The pattern and sensitivity data for the ∑91 are based
on the calculated or estimated average carbon number from the mass spectra of the aromatic fraction (see 15.3). From the
determined average carbon numbers of the hydrocarbon types, a matrix for the saturate fraction is set up using the calibration data
given in Table 3. A sample matrix for the saturate fraction is shown in Table 5. The matrix calculations of the saturate fraction
consists in solving a set of simultaneous linear equations. The results of the matrix calculations (second approximation solutions
are sufficient) are converted to mass fractions by dividing by mass sensitivity. The mass fractions are normalized to the mass
percent of the saturate fraction as determined by the separation procedure.
15.9 Report the mass percent of each hydrocarbon type to the nearest 0.1 % and reference this test method and procedure used.
16. Precision and Bias
16.1 Procedure A—The precision of this test method as obtained by statistical examination of interlaboratory test results on
samples having the composition given in Table 6 is as follows:
16.1.1 Repeatability—The difference between successive test results obtained by the same operator with the same apparatus under
constant operating conditions on identical test material, would be in the long run, in the normal and correct operation of the test
method, exceed the values shown in Table 7 only in one case in twenty.
16.1.2 Reproducibility—The difference between two single and independent results, obtained by different operators working in
different laboratories on identical test material, would in the long run, in the normal and correct operation of the test method,
exceed the values shown in Table 7 only in one case in twenty.
NOTE 9—If samples are analyzed that differ appreciably in composition from those used for the interlaboratory study, this precision statement may not
apply.
NOTE 10—The precision for this test method was not obtained in accordance with
...