ASTM D5739-06(2020)

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.
Designation:D5739 −06 (Reapproved 2020)
Standard Practice for
Oil Spill Source Identification by Gas Chromatography and
Positive Ion Electron Impact Low Resolution Mass
Spectrometry
This standard is issued under the fixed designation D5739; 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 2. Referenced Documents
1.1 This practice covers the use of gas chromatography and 2.1 ASTM Standards:
mass spectrometry to analyze and compare petroleum oil spills D1129 Terminology Relating to Water
and suspected sources. D3325 Practice for Preservation of Waterborne Oil Samples
D3326 Practice for Preparation of Samples for Identification
1.2 The probable source for a spill can be ascertained by the
of Waterborne Oils
examination of certain unique compound classes that also
D3328 Test Methods for Comparison of Waterborne Petro-
demonstrate the most weathering stability. To a greater or
leum Oils by Gas Chromatography
lesser degree, certain chemical classes can be anticipated to
D3414 Test Method for Comparison of Waterborne Petro-
chemically alter in proportion to the weathering exposure time
leum Oils by Infrared Spectroscopy (Withdrawn 2018)
and severity, and subsequent analytical changes can be pre-
D3415 Practice for Identification of Waterborne Oils
dicted. This practice recommends various classes to be ana-
D3650 Test Method for Comparison of Waterborne Petro-
lyzed and also provides a guide to expected weathering-
leum Oils By Fluorescence Analysis (Withdrawn 2018)
induced analytical changes.
D5037 Test Method for Comparison of Waterborne Petro-
1.3 This practice is applicable for moderately to severely
leum Oils by High Performance Liquid Chromatography
degraded petroleum oils in the distillate range from diesel
(Withdrawn 2002)
through Bunker C; it is also applicable for all crude oils with
E355 Practice for Gas ChromatographyTerms and Relation-
comparable distillation ranges. This practice may have limited
ships
applicability for some kerosenes, but it is not useful for
gasolines.
3. Summary of Practice
1.4 The values stated in SI units are to be regarded as 3.1 The recommended chromatography column is a capil-
standard. No other units of measurement are included in this
lary directly interfaced to the mass spectrometer (either qua-
standard. drupole or magnetic).
1.5 This standard does not purport to address all of the
3.2 The low-resolution mass spectrometer is operated in the
safety concerns, if any, associated with its use. It is the
positive ion electron impact mode, 70 eV nominal.
responsibility of the user of this standard to establish appro-
3.3 Mass spectral data are acquired, stored, and processed
priate safety, health, and environmental practices and deter-
with the aid of commercially available computer-based data
mine the applicability of regulatory limitations prior to use.
systems.
1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard-
4. Significance and Use
ization established in the Decision on Principles for the
4.1 This practice is useful for assessing the source for an oil
Development of International Standards, Guides and Recom-
spill. Other less complex analytical procedures (Test Methods
mendations issued by the World Trade Organization Technical
D3328, D3414, D3650, and D5037) may provide all of the
Barriers to Trade (TBT) Committee.
necessary information for ascertaining an oil spill source;
1 2
This practice is under the jurisdiction ofASTM Committee D19 on Water and For referenced ASTM standards, visit the ASTM website, www.astm.org, or
is the direct responsibility of Subcommittee D19.06 on Methods for Analysis for contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Organic Substances in Water. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Jan. 1, 2020. Published January 2020. Originally the ASTM website.
approved in 1995. Last previous edition approved in 2013 as D5739 – 06 (2013). The last approved version of this historical standard is referenced on
DOI: 10.1520/D5739-06R20. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5739−06 (2020)
however, the use of a more complex analytical strategy may be 6.7 Resolution Mixture—Pristane, phytane, n-heptadecane,
necessaryincertaindifficultcases,particularlyforsignificantly and n-octadecane in equal concentration in cyclohexane (50 to
weathered oils.This practice provides the user with a means to 150 ng/µL).
this end.
6.8 Mass Discrimination Mixture—Naphthalene,
4.1.1 This practice presumes that a “screening” of possible
fluoranthene, and benzo (g, h, i) perylene in equal concentra-
suspect sources has already occurred using less intensive
tion in cyclohexane (50 to 150 ng/µL).
techniques. As a result, this practice focuses directly on the
6.9 Reference oil, possibly a crude oil, used for generation
generation of data using preselected targeted compound
oftheextractedionchromatograms(EICs)listedinTable1and
classes. These targets are both petrogenic and pyrogenic and
validation of system performance for oil sample comparison
can constitute both major and minor fractions of petroleum
purposes. (See Appendix X1 for representative EICs produced
oils; they were chosen in order to develop a practice that is
using the conditions stated in Section 8.)
universally applicable to petroleum oil identification in general
and is also easy to handle and apply. This practice can
7. Preparation of Instrumentation
accommodate light oils and cracked products (exclusive of
7.1 Set an initial head pressure of between 5 and 20 psi
gasoline) on the one hand, as well as residual oils on the other.
using helium as the carrier at 250°C (for either a 30-m by
4.1.2 This practice provides analytical characterizations of
0.25-mm inside diameter column or a 30-m by 0.32-mm inside
petroleum oils for comparison purposes. Certain classes of
source-specific chemical compounds are targeted in this quali-
tative comparison; these target compounds are both unique
TABLE 1 Extracted Ion Chromatograms (EICs)
descriptors of an oil and chemically resistant to environmental
degradation. Spilled oil can be assessed in this way as being Approximate Time
Compound Type Ion
Interval, min
similar or different from potential source samples by the direct
Naphthalenes C 156 18 to 23
visual comparison of specific extracted ion chromatograms
C 170 20 to 25
(EICs). In addition, other, more weathering-sensitive chemical A
C 184 22 to 27
compound classes can also be examined in order to crudely
A
Dibenzothiophenes C 184 23 to 28
assess the degree of weathering undergone by an oil spill
C 198 27 to 32
sample.
C 212 29 to 34
C 226 31 to 35
4.2 This practice simply provides a means of making
B
qualitative comparisons between petroleum samples; quantita-
Phenanthrenes/ C 178 27 to 28
anthracenes C 192 28 to 33
tion of the various chemical components is not addressed. 1
C 206 30 to 35
C 220 32 to 37
5. Apparatus
Steranes 14a(H) 217 40 to 60
5.1 Gas Chromatograph Interfaced to a Mass Spectrometer,
14b(H) 218 40 to 60
with a 70-eV electron impact ionization source. The system
Triterpanes 191 40 to 60
shall include a computer for the control of data acquisition and
reduction.
Alkanes 85 4 to 60
5.2 Capillary Column, with a high-resolution, 30 m by
Alkanes 113 4 to 60
0.25-mmor0.32-mminsidediameter(0.25-µm d)(suchasJ&
f
W DB-5 or Supelco PTE-5), interfaced directly to the mass Alkanes and Acyclic 183 4to60
isoprenoids
spectrometer.
Benzonaphthothiophene 234 30 to 34
6. Reagents and Materials
Tri-aromatic steranes 231 39 to 45
6.1 Purity of Reagents—Onlypesticidegrade,nanograde,or
Norhopanes 177 33 to 47
distilled in glass grade solvents will be used.
6.2 Purity of Reference Compounds—All must be certified
Methylhopanes 205 41 to 46
to be at least 95 % pure.
Pyrene/fluoranthene 202 24 to 32
6.3 Septa—Only high-temperature, low-bleed (such as
Methylpyrenes 216 30 to 32
Thermogreen ) shall be used.
Fluorenes 166 16 to 21
6.4 Vials, glass, polytetrafluorethylene-lined screw cap,
10-mL capacity.
Bicyclonaphthalenes 208 15 to 22
A
6.5 Syringes, 10 µL.
Anauthenticstandardofdibenzothiophenecanbechromatographedtoascertain
its actual retention time.
6.6 Perfluorotributylamine, used for tuning the mass spec- B
Phenanthrene is both pyrogenic and petrogenic. Consequently, m/e 178 may
trometer. demonstrateanincreaserelativetoitssourceinspillcasesinwhicharsonorother
combustion processes have occurred. This can result in a significant distortion in
the C anthracene/phenanthrene distribution, which is, generally speaking, coun-
ter to expected weathering processes.
A trademark of Sigma-Aldrich Co., LLC, St. Louis, MO.
D5739−06 (2020)
diameter column). Adjust a final head pressure (for either PracticeD3326forpreparationoftheneatoilsample.(Practice
column) such that the linear velocity is in the range from 30 to D3326 includes Procedure F for recovering oil from thin films
40 cm/s. on water and Procedure G for recovering oil from sand and
debris.) It is the responsibility of the user to validate this
7.2 Mass Spectrometric Tuning:
method for use with these types of matrices since oil recovered
7.2.1 Tune the mass spectrometer to the following perfluo-
from them may contain contamination derived from the sub-
rotributylamine (PFTBA) specification, addressing both mass
strate material.
scale calibration and peak-to-peak ratios:
8.2 Sample Preparation—Weigh 100 to 200 mg of oil into a
(m/e 69 at 100 % of base peak)
A B
(m/e 219 at 35 to 40 % of base peak)
screw-cap glass vial, and add 10 mL cyclohexane. Sonication
C
(m/e 502 at 1 to 2 % of base peak)
may be necessary, as well as centrifugation, to remove particu-
lates if the sample does not dissolve completely.
A
The sensitivity for almost all of the ions monitored (Table 1) can be improved
somewhat by adjusting this percentage to between 60 and 65; however, the
8.3 Instrumental Parameters:
resulting mass spectra may be distorted significantly so that MS computer search
8.3.1 Gas Chromatograph—Use the following parameters:
routines for the identification of unknowns by comparison to conventionally
1-µL splitless injection for 45 s; an initial column temperature
acquired mass spectral libraries may be impaired significantly.
B
Adjust the entrance lens voltage.
of 55°C for 2 min; a temperature ramp at 6°C/min to 270°C; a
C
Adjust the ion focus voltage.
temperature ramp of 3°C/min to 300°C; a final column
7.2.2 Retune every 12 h of mass spectrometer operation.
temperature of 300°C for 17 min; an injection temperature of
290°C; and a mass spectrometer (MS) interface temperature of
7.3 Resolution Check—Under the instrumental conditions
300°C. A total run time of approximately 65 min will be
listed (7.1), pristane and phytane usually display 80 % or
achieved using these parameters.
greater resolution from C and C , respectively. If the
17 18
8.3.2 Mass Spectrometer Data Acquisition Parameters—
resolution is less than 50 %, take corrective action such as
Operate the mass spectrometer in selected ion monitoring
replacement of the injector liner and seals and removal of the
(SIM)forthe24ionslistedinTable2.Sincealloftheionswill
front of the analytical column. Report the degree of resolution
be scanned every second, the dwell time for each is 70 ms.
in Section 10. Refer to Practice E355 for calculation of
Allow a solvent delay time of 4 min before the start of MS
resolution values.
scanning.
7.4 Mass Discrimination Check:
NOTE1—Itisrecognizedthatthedifferentmonitoredclassesofanalytes
7.4.1 Use the gas chromatographic instrumental parameters
elute only in certain regions of the chromatogram; consequently, not all
enumerated in 8.3.1; operate the mass spectrometer, but in the
ions need be monitored continuously. However, no effort has been made
linear scan mode from m/e 45 to 360 in 1 s.
to segment the chromatogram by using different SIM masses at different
7.4.2 Inject a 1-µL solution of naphthalene, fluoranthene,
times for the sake of maintaining simplicity. It is also recognized that the
signal-to-noise ratio is improved by an increase in the dwell time;
andbenzo(g,h,i)peryleneinequalconcentrations(from50to
however, this improvement is directly proportional to the square root of
150 ng/µL) in cyclohexane.
the proportional dwell time increase. A signal-to-noise ratio increase of
7.4.3 Integrate the total ion chromatogram (TIC).
only two would thus result from a four-fold increase in the dwell (from 70
7.4.4 Calculate the following ratios:
to 280 ms). This increased dwell time would permit only 3 ions/s to be
(1) Area of naphthalene to area of fluoranthene, and monitored. Nevertheless, the experienced analyst who is working with a
(2) Area of benzo (g, h, i) perylene to area of fluoranthene.
7.4.5 Theratioof(1)mustbelessthanorequalto2,andthe
TABLE 2 SIM Acquisition
ratio of (2) must be greater than or equal to 0.2. Report this
m/e Dwell/ms Elution Range/min
value in Section 10.
85 70 4 to 60
7.4.6 A high molecular weight response can sometimes be
113 70 4 to 60
improved by changing the penetration of the chromatographic
156 70 4 to 60
166 70 4 to 60
column into the injector body or using silanized glass wool or
170 70 4 to 60
quartz as injector packing material, or both. Electronic flow
177 70 4 to 60
control (instead of constant column head pressure) has recently
178 70 4 to 60
183 70 4 to 60
become available for Capillary GC. It can be used to provide a
184 70 4 to 60
high molecular weight response by increased flow during
191 70 4 to 60
splitless injection. 192 70 4 to 60
198 70 4 to 60
7.5 Retention Time Check—The absolute retention times for
202 70 4 to 60
the mass discrimination check compounds (7.4.2) must be 205 70 4 to 60
206 70 4 to 60
recorded.The batch-to-batch retention time reproducibility can
208 70 4 to 60
be documented in this way. Report these retention times in
212 70 4 to 60
216 70 4 to 60
Section 10.
217 70 4 to 60
218 70 4 to 60
8. Procedure
220 70 4 to 60
226 70 4 to 60
8.1 Refer to Terminology D1129 for terms relating to water
231 70 4 to 60
and Practice D3415 for identification of waterborne oils. Refer
234 70 4 to 60
to Practice D3325 for the preservation of oil samples and
D5739−06 (2020)
well-characterized oil source, such as monitoring degradation over time,
9.1.3 Weathering Stability:
maychoosetomonitorfewerionsinordertomaximizethesignal-to-noise
9.1.3.1 The more highly alkylated homologs are preferred
ratios and consequently improve the sensitivity for a subset of the ions
for characterization purposes over the unsubstituted parent
listed in the table. Similarly, users of certain older model mass spectrom-
compound, or even its monomethylated forms, since both
etersmayalsochoosetomodifySIMacquisitionbymonitoringfewerions
simultaneously in order to offset lowered MS sensitivity. solubility in water and biodegradation are related inversely to
the degree of alkylation.
8.4 Sample Analysis Batching Requirements—Every time
9.1.3.2 In similar fashion, biodegradation and water solu-
the mass spectrometer is used, bracket all samples by a
bility are also related inversely to the number of fused rings.
duplicate analysis, and specifically prepare an oil sample in
Dibenzothiophene and anthracene/phenanthrene are therefore
duplicate (8.2). Also, the first and last samples to be analyzed
inherently more resistant than naphthalenes.
must be these duplicates. Generate the resulting EICs in
accordance with 9.1.1, and compare them visually in accor- 9.1.3.3 Steranes and triterpanes are relatively water in-
dance with 9.1.2; any variations observed will serve to define soluble and are extraordinarily resistant to biodegradation.
the analytical error for the entire batch.
9.1.3.4 The most stable EICs should be examined first,
progressing toward the less stable ones. This order from more
9. Interpretation
weathering stable to less weathering stable is shown in Fig. 1.
9.1 Evaluation of EICs:
9.1.4 Susceptibility of the Various Compound Classes to
9.1.1 Data Presentation—EICs will be generated for each
Weathering Exposure—It may be best to first examine the
oil sample. These EICs are as follows: (1)C through C
highest molecular weight homologous series with the greatest
2 4
homologs of naphthalene, (2) dibenzothiophene and its C –C
1 3 degree of substitution, since weathering results in progressive
homologs, (3) anthracene and phenanthrene and their C –C
losses greatest for the lowest molecular weight homologous
1 3
homologs, (4) triterpanes, (5) steranes, and (6) alkanes, (7)
series with the least degree of substitution, progressing toward
benzonaphthothiophene, (8) tri-aromatic steranes, (9) hopanes,
the highest molecular weight series with the greatest degree of
(10) pyrene/fluoranthene, (11) fluorene and (12) bicyclonaph-
substitution. In those cases in which weathering has not
thalenes. The EICs and their approximate time intervals are
progressed sufficiently to eradicate an entire substituted series
summarizedinTable1.Themethodcanbeextendedtoinclude
completely, the remnants will continue to reflect the original
other suitable ions, if necessary. (With this in mind, the user
ratios of the unweathered oil. The EICs for a weathered oil
may desire to include naphthalene and C naphthalene ho-
1 versusitsunweatheredsourcewillthusremainqualitativelythe
mologs for light, minimally weathered spills or chrysene and
same, that is, the EICs will not change.
its C to C homologous series for heavily weathered residual
1 2
NOTE 2—Asignal-to-noise ratio of 3:1 is used to ascertain the remnant
oils, or both.)
presence of a peak for those weathered oil EICs displaying drastic loss. It
9.1.2 Direct Visual Comparison of EICs—TheEICsforeach
may be helpful to auto-range sections of such an EIC in order to examine
suspect source oil will be compared to the appropriate EICs of
suchalow-levelsignalingreaterdetail.Thissameproceduremaybeused
the spilled oil; evaluation of the patterns (EICs) will be to step around a dominant peak in an EIC in order to auto-range on other,
less dominant peaks and consequently examine them in greater detail.
performed as a peak-to-peak comparison simply by pl
...