Standard Practice for Oil Spill Source Identification by Gas Chromatography and Positive Ion Electron Impact Low Resolution Mass Spectrometry

SIGNIFICANCE AND USE
4.1 This practice is useful for assessing the source for an oil spill. Other less complex analytical procedures (Test Methods D3328, D3414, D3650, and D5037) may provide all of the necessary information for ascertaining an oil spill source; however, the use of a more complex analytical strategy may be necessary in certain difficult cases, particularly for significantly weathered oils. This practice provides the user with a means to this end.  
4.1.1 This practice presumes that a “screening” of possible suspect sources has already occurred using less intensive techniques. As a result, this practice focuses directly on the generation of data using preselected targeted compound classes. These targets are both petrogenic and pyrogenic and can constitute both major and minor fractions of petroleum oils; they were chosen in order to develop a practice that is universally applicable to petroleum oil identification in general and is also easy to handle and apply. This practice can accommodate light oils and cracked products (exclusive of gasoline) on the one hand, as well as residual oils on the other.  
4.1.2 This practice provides analytical characterizations of petroleum oils for comparison purposes. Certain classes of source-specific chemical compounds are targeted in this qualitative comparison; these target compounds are both unique descriptors of an oil and chemically resistant to environmental degradation. Spilled oil can be assessed in this way as being similar or different from potential source samples by the direct visual comparison of specific extracted ion chromatograms (EICs). In addition, other, more weathering-sensitive chemical compound classes can also be examined in order to crudely assess the degree of weathering undergone by an oil spill sample.  
4.2 This practice simply provides a means of making qualitative comparisons between petroleum samples; quantitation of the various chemical components is not addressed.
SCOPE
1.1 This practice covers the use of gas chromatography and mass spectrometry to analyze and compare petroleum oil spills and suspected sources.  
1.2 The probable source for a spill can be ascertained by the examination of certain unique compound classes that also demonstrate the most weathering stability. To a greater or lesser degree, certain chemical classes can be anticipated to chemically alter in proportion to the weathering exposure time and severity, and subsequent analytical changes can be predicted. This practice recommends various classes to be analyzed and also provides a guide to expected weathering—induced analytical changes.  
1.3 This practice is applicable for moderately to severely degraded petroleum oils in the distillate range from diesel through Bunker C; it is also applicable for all crude oils with comparable distillation ranges. This practice may have limited applicability for some kerosenes, but it is not useful for gasolines.  
1.4 The values stated in SI units are to be regarded as the standard.  
1.5 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 and health practices and determine the applicability of regulatory limitations prior to use.

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ASTM D5739-06(2013) - Standard Practice for Oil Spill Source Identification by Gas Chromatography and Positive Ion Electron Impact Low Resolution Mass Spectrometry
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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:D5739 −06 (Reapproved 2013)
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 D3325 Practice for Preservation of Waterborne Oil Samples
D3326 Practice for Preparation of Samples for Identification
1.1 This practice covers the use of gas chromatography and
of Waterborne Oils
mass spectrometry to analyze and compare petroleum oil spills
D3328 Test Methods for Comparison of Waterborne Petro-
and suspected sources.
leum Oils by Gas Chromatography
1.2 The probable source for a spill can be ascertained by the
D3414 Test Method for Comparison of Waterborne Petro-
examination of certain unique compound classes that also
leum Oils by Infrared Spectroscopy
demonstrate the most weathering stability. To a greater or
D3415 Practice for Identification of Waterborne Oils
lesser degree, certain chemical classes can be anticipated to
D3650 Test Method for Comparison of Waterborne Petro-
chemically alter in proportion to the weathering exposure time
leum Oils By Fluorescence Analysis
and severity, and subsequent analytical changes can be pre-
D5037 Test Method for Comparison of Waterborne Petro-
dicted. This practice recommends various classes to be ana-
leum Oils by High Performance Liquid Chromatography
lyzed and also provides a guide to expected weathering—
(Withdrawn 2002)
induced analytical changes.
E355 Practice for Gas ChromatographyTerms and Relation-
1.3 This practice is applicable for moderately to severely ships
degraded petroleum oils in the distillate range from diesel
3. Summary of Practice
through Bunker C; it is also applicable for all crude oils with
comparable distillation ranges. This practice may have limited
3.1 The recommended chromatography column is a capil-
applicability for some kerosenes, but it is not useful for
lary directly interfaced to the mass spectrometer (either qua-
gasolines.
drupole or magnetic).
1.4 The values stated in SI units are to be regarded as the
3.2 The low-resolution mass spectrometer is operated in the
standard.
positive ion electron impact mode, 70 eV nominal.
1.5 This standard does not purport to address all of the
3.3 Mass spectral data are acquired, stored, and processed
safety concerns, if any, associated with its use. It is the
with the aid of commercially available computer-based data
responsibility of the user of this standard to establish appro-
systems.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. 4. Significance and Use
4.1 This practice is useful for assessing the source for an oil
2. Referenced Documents
spill. Other less complex analytical procedures (Test Methods
2.1 ASTM Standards:
D3328, D3414, D3650, and D5037) may provide all of the
D1129 Terminology Relating to Water
necessary information for ascertaining an oil spill source;
however, the use of a more complex analytical strategy may be
necessaryincertaindifficultcases,particularlyforsignificantly
This practice is under the jurisdiction ofASTM Committee D19 on Water and
weathered oils.This practice provides the user with a means to
is the direct responsibility of Subcommittee D19.06 on Methods for Analysis for
Organic Substances in Water. this end.
Current edition approved Feb. 15, 2013. Published March 2013. Originally
4.1.1 This practice presumes that a “screening” of possible
approved in 1995. Last previous edition approved in 2006 as D5739 – 06. DOI:
suspect sources has already occurred using less intensive
10.1520/D5739-06R13.
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 last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5739−06 (2013)
TABLE 1 Extracted Ion Chromatograms (EICs)
techniques. As a result, this practice focuses directly on the
generation of data using preselected targeted compound Approximate Time
Compound Type Ion
Interval, min
classes. These targets are both petrogenic and pyrogenic and
Naphthalenes C 156 18 to 23
can constitute both major and minor fractions of petroleum
C 170 20 to 25
oils; they were chosen in order to develop a practice that is A
C 184 22 to 27
universally applicable to petroleum oil identification in general
A
Dibenzothiophenes C 184 23 to 28
and is also easy to handle and apply. This practice can
C 198 27 to 32
accommodate light oils and cracked products (exclusive of
C 212 29 to 34
gasoline) on the one hand, as well as residual oils on the other. C 226 31 to 35
4.1.2 This practice provides analytical characterizations of
B
Phenanthrenes/ C 178 27 to 28
petroleum oils for comparison purposes. Certain classes of
anthracenes C 192 28 to 33
C 206 30 to 35
source-specific chemical compounds are targeted in this quali-
C 220 32 to 37
tative comparison; these target compounds are both unique
descriptors of an oil and chemically resistant to environmental
Steranes 14a(H) 217 40 to 60
14b(H) 218 40 to 60
degradation. Spilled oil can be assessed in this way as being
similar or different from potential source samples by the direct
Triterpanes 191 40 to 60
visual comparison of specific extracted ion chromatograms
(EICs). In addition, other, more weathering-sensitive chemical Alkanes 85 4 to 60
compound classes can also be examined in order to crudely
Alkanes 113 4 to 60
assess the degree of weathering undergone by an oil spill
Alkanes and Acyclic 183 4to60
sample.
isoprenoids
4.2 This practice simply provides a means of making
Benzonaphthothiophene 234 30 to 34
qualitative comparisons between petroleum samples; quantita-
tion of the various chemical components is not addressed.
Tri-aromatic steranes 231 39 to 45
5. Apparatus Norhopanes 177 33 to 47
5.1 Gas Chromatograph Interfaced to a Mass Spectrometer,
Methylhopanes 205 41 to 46
with a 70-eV electron impact ionization source. The system
Pyrene/fluoranthene 202 24 to 32
shall include a computer for the control of data acquisition and
reduction.
Methylpyrenes 216 30 to 32
5.2 Capillary Column, with a high-resolution, 30 m by
Fluorenes 166 16 to 21
0.25-mmor0.32-mminsidediameter(0.25-µm d)(suchasJ&
f
Bicyclonaphthalenes 208 15 to 22
W DB-5 or Supelco PTE-5), interfaced directly to the mass
A
Anauthenticstandardofdibenzothiophenecanbechromatographedtoascertain
spectrometer.
its actual retention time.
B
Phenanthrene is both pyrogenic and petrogenic. Consequently, m/e 178 may
6. Reagents and Materials
demonstrateanincreaserelativetoitssourceinspillcasesinwhicharsonorother
combustion processes have occurred. This can result in a significant distortion in
6.1 Purity of Reagents—Onlypesticidegrade,nanograde,or
the C anthracene/phenanthrene distribution, which is, generally speaking, coun-
distilled in glass grade solvents will be used.
ter to expected weathering processes.
6.2 Purity of Reference Compounds—All must be certified
to be at least 95 % pure.
validation of system performance for oil sample comparison
6.3 Septa—Only high-temperature, low-bleed (such as
purposes. (See Appendix X1 for representative EICs produced
TM
Thermogreen ) shall be used.
using the conditions stated in section 8.)
6.4 Vials, glass, polytetrafluorethylene-lined screw cap,
7. Preparation of Instrumentation
10-mL capacity.
7.1 Set an initial head pressure of between 5 and 20 psi
6.5 Syringes, 10 µL.
using helium as the carrier at 250°C (for either a 30-m by
6.6 Perfluorotributylamine, used for tuning the mass spec-
0.25-mm inside diameter column or a 30-m by 0.32-mm inside
trometer.
diameter column). Adjust a final head pressure (for either
column) such that the linear velocity is in the range from 30 to
6.7 Resolution Mixture—Pristane, phytane, n-heptadecane,
40 cm/s.
and n-octadecane in equal concentration in cyclohexane (50 to
150 ng/µL).
7.2 Mass Spectrometric Tuning:
7.2.1 Tune the mass spectrometer to the following perfluo-
6.8 Mass Discrimination Mixture—Naphthalene,
rotributylamine (PFTBA) specification, addressing both mass
fluoranthene, and benzo (g, h, i) perylene in equal concentra-
scale calibration and peak-to-peak ratios:
tion in cyclohexane (50 to 150 ng/µL).
6.9 Reference oil, possibly a crude oil, used for generation
oftheextractedionchromatograms(EICs)listedinTable1and
D5739−06 (2013)
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
acquired mass spectral libraries may be impaired significantly. 1-µL splitless injection for 45 s; an initial column temperature
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;
and benzo (g,h,i) perylene in equal concentrations (from 50 to
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
well-characterized oil source, such as monitoring degradation over time,
(2) Area of benzo (g,h,i) perylene to area of fluoranthene.
maychoosetomonitorfewerionsinordertomaximizethesignal-to-noise
7.4.5 Theratioof(1)mustbelessthanorequalto2,andthe
ratios and consequently improve the sensitivity for a subset of the ions
ratio of (2) must be greater than or equal to 0.2. Report this
listed in the table. Similarly, users of certain older model mass spectrom-
value in Section 10.
etersmayalsochoosetomodifySIMacquisitionbymonitoringfewerions
simultaneously in order to offset lowered MS sensitivity.
7.4.6 A high molecular weight response can sometimes be
improved by changing the penetration of the chromatographic
8.4 Sample Analysis Batching Requirements—Every time
column into the injector body or using silanized glass wool or
the mass spectrometer is used, bracket all samples by a
quartz as injector packing material, or both. Electronic flow
control (instead of constant column head pressure) has recently
TABLE 2 SIM Acquisition
become available for Capillary GC. It can be used to provide a
m/e Dwell/ms Elution range/min
high molecular weight response by increased flow during
85 70 4 to 60
splitless injection.
113 70 4 to 60
7.5 Retention Time Check—The absolute retention times for 156 70 4 to 60
166 70 4 to 60
the mass discrimination check compounds (7.4.2) must be
170 70 4 to 60
recorded.The batch-to-batch retention time reproducibility can
177 70 4 to 60
be documented in this way. Report these retention times in 178 70 4 to 60
183 70 4 to 60
Section 10.
184 70 4 to 60
191 70 4 to 60
192 70 4 to 60
8. Procedure
198 70 4 to 60
8.1 Refer to Terminology D1129 for terms relating to water 202 70 4 to 60
205 70 4 to 60
and Practice D3415 for identification of waterborne oils. Refer
206 70 4 to 60
to Practice D3325 for the preservation of oil samples and
208 70 4 to 60
PracticeD3326forpreparationoftheneatoilsample.(Practice 212 70 4 to 60
216 70 4 to 60
D3326 includes Procedure F for recovering oil from thin films
217 70 4 to 60
on water and Procedure G for recovering oil from sand and
218 70 4 to 60
debris.) It is the responsibility of the user to validate this 220 70 4 to 60
226 70 4 to 60
method for use with these types of matrices since oil recovered
231 70 4 to 60
from them may contain contamination derived from the sub-
234 70 4 to 60
strate material.
D5739−06 (2013)
duplicate analysis, and specificall
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