ASTM D2425-04(2009)
(Test Method)Standard Test Method for Hydrocarbon Types in Middle Distillates by Mass Spectrometry
Standard Test Method for Hydrocarbon Types in Middle Distillates by Mass Spectrometry
SIGNIFICANCE AND USE
A knowledge of the hydrocarbon composition of process streams and petroleum products boiling within the range of 400 to 650°F (204 to 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.
SCOPE
1.1 This test method covers an analytical scheme using the mass spectrometer to determine the hydrocarbon types present in virgin middle distillates 204 to 343°C (400 to 650°F) boiling range, 5 to 95 volume % as determined by Test Method D86. Samples with average carbon number value of paraffins between C12 and C16 and containing paraffins from C10 and C18 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 (acenaphthylenes, etc.), and tricyclic aromatics.
Note 1—This 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 for information only.
1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For a specific warning statement, see 10.1.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D2425 − 04 (Reapproved 2009)
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.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Terminology
1.1 This test method covers an analytical scheme using the
3.1 The summation of characteristic mass fragments are
mass spectrometer to determine the hydrocarbon types present
defined as follows:
+
invirginmiddledistillates204to343°C(400to650°F)boiling
∑71 (paraffins)=total peak height of m/e 71 + 85.
range, 5 to 95 volume% as determined by Test Method D86.
∑67 (mono or noncondensed polycycloparaffins, or
+
Samples with average carbon number value of paraffins be-
both) = total peak height of m/e 67+68+69+81
tween C and C and containing paraffins from C and C
12 16 10 18
+82+83+96+97.
can be analyzed. Eleven hydrocarbon types are determined.
∑123 (condensed dicycloparaffins)=total peak height of
+
These include: paraffins, noncondensed cycloparaffins, con-
m/e 123+124+137+138+··· etc. up to 249+250.
densed dicycloparaffins, condensed tricycloparaffins,
∑149 (condensed tricycloparaffins)=total peak height of
alkylbenzenes, indans or tetralins, or both, C H (indenes, +
n 2n-10
m/e 149+150+163+164+··· etc. up to 247+248.
etc.), naphthalenes, C H (acenaphthenes, etc.),
n 2n-14 +
∑91 (alkyl benzenes) = total peak height of m/e
C H (acenaphthylenes, etc.), and tricyclic aromatics.
n 2n-16
91+92+105+106+··· etc. up to 175+176.
NOTE 1—This test method was developed on Consolidated Electrody-
∑103 (indans or tetralins, or both)=total peak height of
+
namics Corporation Type 103 Mass Spectrometers.
m/e 103+104+117+118+··· etc. up to 187+188.
1.2 The values stated in SI units are to be regarded as the
∑115 (indenes or C H , or both)=total peak height of
n 2n-10
+
standard. The inch-pound units given in parentheses are for
m/e 115+116+129+130+··· etc. up to 185+186.
+
information only.
128 (naphthalene)=total peak height of m/e 128.
+
1.3 This standard does not purport to address all of the ∑141 (naphthalenes) = total peak height of m/e
safety problems, if any, associated with its use. It is the
141+142+155+156+··· etc. up to 239+240.
responsibility of the user of this standard to establish appro-
∑153 (acenaphthenes or C H , or both)=total peak
n 2n-14
+
priate safety and health practices and determine the applica-
height of m/e 153 + 154 + 167 + 168 + ··· etc. up to
bility of regulatory limitations prior to use. For a specific
251+252.
warning statement, see 10.1.
∑151 (acenaphthylenes or C H , or both)=total peak
n 2n-16
+
height of m/e 151 + 152 + 165 + 166 + ··· etc. up to
2. Referenced Documents
249+250.
+
2.1 ASTM Standards:
∑177 (tricyclic aromatics) = total peak height of m/e
D86Test Method for Distillation of Petroleum Products at
177+178+191+192+··· etc. up to 247+248.
Atmospheric Pressure
D2549Test Method for Separation of Representative Aro-
4. Summary of Test Method
matics and Nonaromatics Fractions of High-Boiling Oils
4.1 Samples are separated into saturate and aromatic frac-
by Elution Chromatography
tions by Test Method D2549, and each fraction is analyzed by
mass spectrometry. The analysis is based on the summation of
This test method is under the jurisdiction of ASTM Committee D02 on
characteristicmassfragmentstodeterminetheconcentrationof
Petroleum Products and Lubricantsand is the direct responsibility of Subcommittee
hydrocarbon types. The average carbon numbers of the hydro-
D02.04.0M on Mass Spectroscopy.
carbon types are estimated from spectral data. Calculations are
Current edition approved Oct. 1, 2009. Published November 2009. Originally
madefromcalibrationdatadependentupontheaveragecarbon
approved in 1965. Last previous edition approved in 2004 as D2425–04. DOI:
10.1520/D2425-04R09.
number of the hydrocarbon types. The results of each fraction
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
are mathematically combined according to their mass fractions
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
as determined by the separation procedure. Results are ex-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. pressed in mass percent.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2425 − 04 (2009)
+
NOTE 2—Test Method D2549 is presently applicable only to samples
groundpeaksfromasaturatefractionat m/e 69and71should
having 5% points of 232°C (450°F) or greater.
bereducedtolessthan0.1%ofthecorrespondingpeaksinthe
mixture spectrum after a normal pump out time of 2 to 5 min.
5. Significance and Use
5.1 Aknowledgeofthehydrocarboncompositionofprocess 10. Mass Spectrometric Procedure
streamsandpetroleumproductsboilingwithintherangeof400
10.1 Obtaining the Mass Spectrum for Each Chromato-
to 650°F (204 to 343°C) is useful in following the effect of
graphic Fraction—Using a microburet or constant-volume
changes in process variables, diagnosing the source of plant
pipet, introduce sufficient sample through the inlet sample to
upsets, and in evaluating the effect of changes in composition
give a pressure of 2 to 4 Pa (15 to 30 mtorr) in the inlet
on product performance properties.
reservoir. (Warning—Hydrocarbon samples of this boiling
range are combustible.) Record the mass spectrum of the
6. Interferences
+
sample from m/e 40 to 292 using the instrument conditions
6.1 Nonhydrocarbon types, such as sulfur and nitrogen-
outlined in 8.1.1-8.1.3.
containingcompounds,arenotincludedinthematricesforthis
11. Calculations
test method. If these nonhydrocarbon types are present to any
largeextent,(forexample,masspercentsulfur>0.25)theywill
11.1 Aromatic Fraction—Readpeakheightsfromtherecord
+
interfere with the spectral peaks used for the hydrocarbon-type
mass spectrum corresponding to m/e ratios of 67 to 69, 71, 81
calculation.
to 83, 85, 91, 92, 96, 97, 103 to 106, 115 to 120, 128 to 134,
141to148,151to162,165to198,203to212,217to226,231
7. Apparatus
to 240, 245, 246, 247 to 252.
7.1 Mass Spectrometer—The suitability of the mass spec-
Find:
trometer to be used with this method of analysis shall be
71 5 71185 (1)
(
proven by performance tests described herein.
67 5 67168169181182183196197 (2)
(
7.2 Sample Inlet System—Any inlet system permitting the
N56
introduction of the sample without loss, contamination, or
91 5 91114N 1 92114N (3)
@~ ! ~ !#
( ( N50
change in composition. To fulfill these requirements it will be
N56
103 5 @ 103114N 1 104114N # (4)
~ ! ~ !
( ( N50
necessary to maintain the system at an elevated temperature in
N55
the range of 125 to 325°C and to provide an appropriate
115 5 @~115114N!1~116114N!# (5)
( ( N50
sampling device.
N57
141 5 141114N 1 142114N (6)
@~ ! ~ !#
( ( N50
7.3 Microburet or Constant-Volume Pipet.
N57
153 5 153114N 1 154114N (7)
@~ ! ~ !#
( ( N50
8. Calibration
N57
151 5 @~151114N!1~152114N!# (8)
( ( N50
8.1 Calibration coefficients are attached which can be used
N55
177 5 177114N 1 178114N (9)
@~ ! ~ !#
directly provided: ( ( N50
+
8.1.1 Repeller settings are adjusted to maximize the m/e
11.2 Calculate the mole fraction at each carbon number of
226 ion of n-hexadecane.
the alkylbenzenes for n=10to n=18 as follows:
8.1.2 Amagneticfieldisusedthatwillpermitscanningfrom
µ 5 P 2 P K /K (10)
+ ~ !
@ #
n m m21 1 2
m/e 40 to 292.
8.1.3 An ionization voltage of 70 eV and ionizing currents
in the range 10 to 70 µA are used.
TABLE 1 Parent Ion Isotope Factors and Mole Sensitivities
NOTE 3—The calibration coefficients were obtained for ion source Isotope Mole
Carbon No. m/e
Factor, K Sensitivity, K
conditions such that the∑67/∑71 ratio for n-hexadecane was 0.26/1. The
1 2
Alkylbenzenes
cooperativestudyofthistestmethodindicatedanacceptablerangeforthis
10 134 0.1101 85
∑ ratio between 0.2/1 to 0.30/1.
11 148 0.1212 63
NOTE 4—Users of instruments other than Consolidated Electrodynam-
12 162 0.1323 60
ics Corporation Type 103 Mass Spectrometers may have to develop their
13 176 0.1434 57
own operating parameters and calibration data.
14 190 0.1545 54
15 204 0.1656 51
9. Performance Test 16 218 0.1767 48
17 232 0.1878 45
9.1 Generally, mass spectrometers are in continuous opera-
18 246 0.1989 42
L L
tion and should require no additional preparation before 1 2
Naphthalenes
analyzingsamples.Ifthespectrometerhasbeenturnedononly
11 142 0.1201 194
recently, it will be necessary to check its operation in accor-
12 156 0.1314 166
13 170 0.1425 150
dance with this method and instructions of the manufacturer to
14 184 0.1536 150
ensure stability before proceeding.
15 198 0.1647 150
16 212 0.1758 150
9.2 Mass Spectral Background—Samples in the carbon
17 226 0.1871 150
number range C to C should pump out so that less than
10 18 18 240 0.1982 150
0.1% of the two largest peaks remain. For example, back-
D2425 − 04 (2009)
where: represented by ∑’s 103, 115, 153, and 151, are usually
relatively low in concentration so that their parent ions are
µ = mole fraction of each alkylbenzene as represented
n
affectedbyothertypespresent.Thecalculationoftheiraverage
by n which indicates the number of carbons in each
carbonnumberisnotstraightforward.Therefore,theiraverage
molecular species.
m = molecular weight of the alkylbenzene being calcu- carbon numbers are estimated by inspection of the aromatic
spectrum. Generally, their average carbon numbers may be
lated,
m−1 = molecular weight minus 1, taken to be equivalent to that of the naphthalenes, or to the
P = polyisotopic mixture peak at m, m−1,
closest whole number thereof, as calculated in 11.5. The
K = isotopic correction factor (see Table 1), and
1 averagecarbonnumberoftricyclicaromatics∑177hastobeat
K = mole sensitivity for n (see Table 1).
leastC andinfullboilingrangemiddledistillatesC maybe
14 14
NOTE 5—This step of calculation assumes no mass spectral pattern
used to represent the ∑177 types carbon number. From the
contributions from other hydrocarbon types to the parent and parent-1
calculated and estimated average carbon numbers of the
peaks of the alkylbenzenes. Selection of the lowest carbon number 10 is
hydrocarbon types, a matrix for the aromatic fraction is set up
based upon the fact that C alkylbenzenes boil below 204°C (400°F) and
their concentration can be considered negligible. usingthecalibrationdatagiveninTable3.Asamplematrixfor
the aromatic fraction is shown in Table 4. The matrix calcula-
11.3 Find the average carbon number of the alkylbenzenes,
tions consist in solving a set of simultaneous linear equations.
A, in the aromatic fraction as follows:
The pattern coefficients are listed in Table 3.The constants are
n518 n518
A 5 n 3 µ / µ (11)
~ ! ~ !
n n
(n510 (n510
the ∑ values determined from the mass spectrum. Second
approximation solutions are of sufficient accuracy. If many
11.4 Calculate the mole fraction at each carbon number of
analyses are performed using the same type of a matrix, the
the naphthalenes for n=11to n=18 as follows:
matrix may be inverted for simpler, more rapid desk calcula-
x 5 P 2 P L /L (12)
~ !
n @ m m21 1 # 2
tion. Matrices may also be programmed for automatic com-
where: puter operations. The results of matrix calculations are con-
verted to mass fractions by dividing by mass sensitivity. The
x = molefractionofeachnaphthaleneasrepresentedby
n
mass fractions are normalized to the mass percent of the
n which indicates the number of carbons in each
aromatic fraction, as determined by the separation procedure.
molecular species,
m = molecular weight of the naphthalenes being calcu-
11.7 Saturate Fraction—Read peak at heights from the
lated,
+
recordofthemassspectrumcorrespondingto m/e ratiosof67
m−1 = molecular weight minus 1,
to 69, 71, 81 to 83, 85, 91, 92, 96, 97, 105, 106, 119, 120, 123,
P = polyisotopic mixture peak at m, m−1,
124, 133, 134, 137, 138, 147 to 152, 161 to 166, 175 to 180,
L = isotopic correction factor (see Table 1), and
191 to 194, 205 to 208, 219 to 222, 233 to 236, 247 to 250.
L = mole sensitivity for n (see Table 1).
Find:
NOTE 6—This step of calculation assumes no mass spectral pattern
contributions to the parent and parent-1 peaks of the naphthalenes. The
71 5 71185 (14)
(
concentration of naphthalene itself at a molecular weight of 128 shall be
+
determined separately from the polyisotopic peak at m/e 128 in the
67 5 67168169181182183196197 (15)
(
matrix calculation. The average carbon number for the naphthalenes shall
N59
be calculated from carbon number 11 (molecular weight 142) to 18
123 5 123114N 1 124114N (16)
@~ ! ~ !#
( ( N50
(molecular weight 240).
N57
149 5 149114N 1 150114N (17)
@~ ! ~ !#
( ( N50
11.5 Find the average carbon number of the naphthalenes,
N56
B, in the aromatic fraction as follows:
91 5 @~91114N!1~92114N!# (18)
( ( N50
n518 n518
B 5 nx / x (13)
~ ! ~ !
n n
(n511 (n511 11.8 Selection of the pattern and sensitivity data for matrix
calculation is dependent upon the average carbon number of
11.6 Selection of pattern and sensitivity data for matrix
the types present. The average carbon number of the paraffins
carbon number of the types present. The average carbon
and cycloparaffin types (∑’s 71, 69, 123, and 149), are related
number of the paraffins and cycloparaffins (∑71 and ∑67,
to the calculated average carbon number of the alkylbenzenes
respectively)arerelatedtothecalculatedaveragecarbonofthe
of the aromatic fraction (11.3), as shown in Table 2. The ∑91
alkylbenzenes (11.3), as shown in Table 2. Both∑71 and∑67
is included in the saturate fraction as a check on the efficiency
are included in the aromatic fraction matrix to check on
oftheseparationprocedure.Thepatternandsensitivitydatafor
possible overlap in the separation. The other types present,
the ∑91 are based on the calculated or estimated average
carbon number from the mass spectra of the aromatic fraction
TABLE 2 Relationship Between Average Carbon Numbers of
(see11.3).Fromthedeterminedaveragecarbonnumbersofthe
Alkylbenzenes, Paraffins, and Cycloparaffins
hydrocarbon types, a matrix for the saturate fraction is set up
Alkylbenzenes Paraffin and Cycloparaffin
usingthecalibrationdatagiveninTable3.Asamplematrixfor
Average Carbon No. Average Carbon No.
the saturate fraction is shown in Table 5. The matrix calcula-
10 11
11 12 tions of the saturate fraction consists in solving a set of
12 13
simultaneous linear equations. The results of the matrix calcu-
13 15 (14.5)
lations
...
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