ASTM D3650-93(2006)
(Test Method)Standard Test Method for Comparison of Waterborne Petroleum Oils By Fluorescence Analysis
Standard Test Method for Comparison of Waterborne Petroleum Oils By Fluorescence Analysis
SIGNIFICANCE AND USE
This test method is useful for rapid identification of waterborne petroleum oil samples as well as oil samples obtained from fuel or storage tanks, or from sand, vegetation, or other substrates. This test method is applicable to weathered and unweathered neat oil samples.
The unknown oil is identified through the comparison of the fluorescence spectrum of the oil with the spectra (obtained at similar instrumental settings on the same instrument) of possible source samples. A match of the entire spectrum between the unknown and possible source sample indicates a common source.
SCOPE
1.1 This test method covers the comparison of waterborne petroleum oils with oils from possible sources by means of fluorescence spectroscopy (). Useful references for this test method include: () and () for fluorescence analysis in general and (), (), and () for oil spill identification including fluorescence.
1.2 This test method is applicable to crude or refined petroleum products, for any sample of neat oil, waterborne oil, or sample of oil-soaked material. Unless the samples are collected soon after the spill occurs, it is not recommended that volatile fuels such as gasoline, kerosine, and No. 1 fuel oils be analyzed by this test method, because their fluorescence signatures change rapidly with weathering. Some No. 2 fuel oils and light crude oils may only be identifiable up to 2 days weathering, or less, depending on the severity of weathering. In general, samples weathered up to 1 week may be identified, although longer periods of weathering may be tolerated for heavy residual oils, oil weathered under Arctic conditions, or oil that has been protected from weathering by collecting in a thick layer.
1.3 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.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D3650 – 93 (Reapproved 2006)
Standard Test Method for
Comparison of Waterborne Petroleum Oils By
Fluorescence Analysis
This standard is issued under the fixed designation D3650; 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* D1193 Specification for Reagent Water
D3325 Practice for Preservation ofWaterborne Oil Samples
1.1 This test method covers the comparison of waterborne
D3326 Practice for Preparation of Samples for Identifica-
petroleum oils with oils from possible sources by means of
2 tion of Waterborne Oils
fluorescence spectroscopy (1). Useful references for this test
D3415 Practice for Identification of Waterborne Oils
methodinclude:(2)and(3)forfluorescenceanalysisingeneral
D4489 Practices for Sampling of Waterborne Oils
and (4), (5), and (6) for oil spill identification including
E131 Terminology Relating to Molecular Spectroscopy
fluorescence.
E275 Practice for Describing and Measuring Performance
1.2 This test method is applicable to crude or refined
of Ultraviolet and Visible Spectrophotometers
petroleum products, for any sample of neat oil, waterborne oil,
E520 Practice for Describing Photomultiplier Detectors in
or sample of oil-soaked material. Unless the samples are
Emission and Absorption Spectrometry
collectedsoonafterthespilloccurs,itisnotrecommendedthat
volatile fuels such as gasoline, kerosine, and No. 1 fuel oils be
3. Terminology
analyzed by this test method, because their fluorescence
3.1 Definitions—For definitions of terms used in this test
signatures change rapidly with weathering. Some No. 2 fuel
method refer to Terminology D1129, Practice D3415, and
oils and light crude oils may only be identifiable up to 2 days
Terminology E131.
weathering,orless,dependingontheseverityofweathering.In
general, samples weathered up to 1 week may be identified,
4. Summary of Test Method
although longer periods of weathering may be tolerated for
4.1 This test method consists of fluorescence analyses of
heavy residual oils, oil weathered under Arctic conditions, or
dilute solutions of oil in spectroquality cyclohexane. In most
oil that has been protected from weathering by collecting in a
cases the emission spectra, with excitation at 254 nm, over the
thick layer.
spectral range from 280 to 500 nm, are adequate for matching.
1.3 This standard does not purport to address all of the
4.2 Identification of the sample is made by direct visual
safety concerns, if any, associated with its use. It is the
comparison of the sample’s spectrum with the spectra from
responsibility of the user of this standard to establish appro-
possible source samples.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
NOTE 1—When weathering has occurred, it may be necessary to
consider known weathering trends when matching spectra (Fig. 1 and Fig.
2. Referenced Documents
2).
2.1 ASTM Standards:
5. Significance and Use
D1129 Terminology Relating to Water
5.1 This test method is useful for rapid identification of
waterborne petroleum oil samples as well as oil samples
This test method is under the jurisdiction of ASTM Committee D19 on Water
obtained from fuel or storage tanks, or from sand, vegetation,
andisthedirectresponsibilityofSubcommitteeD19.06onMethodsforAnalysisfor
or other substrates.This test method is applicable to weathered
Organic Substances in Water.
Current edition approved Feb. 15, 2006. Published February 2006. Originally
and unweathered neat oil samples.
approved in 1978. Last previous edition approved in 1999 as D3650 – 93 (1999).
5.2 Theunknownoilisidentifiedthroughthecomparisonof
DOI: 10.1520/D3650-93R06.
2 the fluorescence spectrum of the oil with the spectra (obtained
The boldface numbers in parentheses refer to the references at the end of this
test method. at similar instrumental settings on the same instrument) of
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
possible source samples. A match of the entire spectrum
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
between the unknown and possible source sample indicates a
Standards volume information, refer to the standard’s Document Summary page on
common source.
the ASTM website.
*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.
D3650 – 93 (2006)
TABLE 1 Specifications for Fluorescence Spectrophotometers
Wavelength Reproducibility
Excitation monochromator better than62nm
Emission monochromator better than 62nm
Gratings (Typical Values)
Excitation monochromator minimum of 600 lines/mm blazed at
A
300 nm
Emission monochromator minimum of 600 lines/mm blazed at
A
300 nm or 500 nm
B
Photomultiplier Tube
C D E
Either S-20 or S-5 Response
Resolution
Excitation monochromator better than 2 nm
Emission monchromator better than 2 nm
FIG. 1 Fluorescence Spectra for a Typical No. 2 Fuel Oil
Time Constant
(Unweathered and Weathered One Day)
not to exceed one second
A
Or designed to have a good efficiency in this spectral region.
B
See Practice E520.
C
Photomultiplier tubes such as Hamamatsu R-446-UR.
D
Photomultiplier tubes such as RCA 1P28 or Hamamatsu R-106.
E
Or equivalent having a good spectral response in the spectral region from 280
to 600 nm.
7.2 Excitation Source—A high-pressure xenon lamp (a
150-W xenon lamp has proven acceptable). Other continuum
sources, such as deuterium or high-pressure xenon-mercury,
which have sufficient intensity in the ultraviolet region, could
be used as excitation sources.
NOTE 4—Line sources such as a low-pressure mercury lamp may also
be used for excitation at 254 nm, if the flexibility of using arbitrary
FIG. 2 Fluorescence Spectra for a Typical No. 6 Fuel Oil
excitation wavelengths or excitation spectra is not desired and if source
(Unweathered and Weathered One Day)
intensity is adequate.
7.3 Fluorescence Cells—Standard cells, made from
6. Interferences
fluorescence-free fused silica with a pathlength of 10 mm and
6.1 The fluorescence spectrum will be distorted if an oil
a height of 45 mm.
sample has been contaminated by an appreciable amount, for
7.4 Recorder or Computer—Strip chart or X-Y recorder,
example, 1 % of common chemical impurities such as other
with a response time less than 1 s for full-scale deflection, or a
oils that are fluorescent on excitation at 254 nm.
computer capable of digitizing the data at a rate of 1 data point
NOTE 2—Storage of samples in improper containers (for example,
per nanometre.
plastics) may result in contamination. This interference can be eliminated
7.5 Cell-Filling Device—Disposable Pasteur capillary pi-
by observing proper procedures for collection and preservation of
pet.
samples. Refer to Practice D3325.
7.6 Volumetric Flasks—Low-actinic glass, ground-glass
NOTE 3—“Spectroquality” cyclohexane may not have a low enough
stoppered volumetric flasks (100-mL).
fluorescence solvent blank. Lots vary in the content of fluorescent
7.7 Micropipet, 10 to 50-µL capacity.
impurities, which may increase with storage time even if the bottle is
unopened.
7.8 AnalyticalBalance,withaprecisionofatleast 60.1mg.
7.9 Weighing Pans, 5 to 7-mm diameter, 18 mm deep, made
6.2 Oil residues may build up in fluorescence cells particu-
of aluminum or equivalent.
larly after prolonged usage with heavy oils. In such a case,
7.10 Test Tubes, disposable 15-mL glass test tubes.
follow the procedure using nitric acid for cleaning glassware
7.11 Micropipet, or microsyringe, 9-µL capacity; with an
(10.1.3).
accuracy of 1 % and reproducibility of 0.1 % of pipet capacity.
6.3 Possible interferences from Raman or RayleighTyndall
7.12 Micropipet, 200-µLcapacity with disposable tips; with
scattering are not observed in the emission scan ranges
an accuracy of 1 % and reproducibility of 0.1 % of pipettor
selected.
capacity.
7. Apparatus
7.13 Solvent Dispenser, adjustable to deliver 10 mL.
7.1 Fluorescence Spectrophotometer (or Spectro- 7.14 Vortex Mixer.
fluorometer)—An instrument recording in the spectral range of
8. Reagents and Materials
220 nm to at least 600 nm for both excitation and emission
responses and capable of meeting the specifications stated in 8.1 Purity of Reagents—Spectroquality grade reagents
Table 1. should be used in all instances unless otherwise stated. It is
D3650 – 93 (2006)
intended that all reagents shall conform to the specifications of ensure that all oil dissolves. Occasionally, depending on
theCommitteeonAnalyticalReagentsoftheAmericanChemi- fluorescence yield of the oil tested and instrumentation used, it
cal Society, where such specifications are available. maybenecessarytouse100ppmconcentrationtogetadequate
8.2 Purity of Water— References to water shall be under- fluorescence intensity. In these cases, weigh out 0.0078 6
stood to mean Type IV reagent water conforming to Specifi- 0.0001 g of oil and proceed as above.
cationD1193. However,sincefluorescentorganicimpurities in
NOTE 7—It is preferable that the prepared solution be used the same
thewatermayconstituteaninterference,thepurityofthewater
day. Do not use solutions that have been standing for periods in excess of
should be checked by running a water blank using the same
6 h unless they have been refrigerated. In no case use solutions more than
instrument conditions as for the solvent blank. 2 days old.
8.3 Acetone (CH COCH ).
3 3 9.4.2 Volume Technique—Allow the prepared oil sample to
8.4 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
come to room temperature and shake until they are homoge-
(HNO ).
3 neous.Transfer 9 µLof the oil to a 15-mLdisposable glass test
8.5 Cyclohexane, spectroquality grade, with a fluorescence
tube with a micropipet or microsyringe and add 10 mL of
solvent blank less than 2 % of the intensity of the major peak
spectroquality cyclohexane with a solvent dispenser. Place a
of the sample fluorescence generated with the same instrumen-
capofaluminumfoiloverthetopofthetesttubeandvortexfor
tal settings over the emission range used. Cyclohexane is
approximately 30 s. With a micropipet, transfer 200 µL of this
dispensed throughout the procedure from a 500-mL TFE-
solution to a second 15-mL test tube and then add 10 mL of
fluorocarbon wash bottle. For prolonged storage, cyclohexane
cyclohexane. Place a cap of aluminum foil over the top of the
should be stored only in glass. Check the suitability of the
second test tube and vortex for approximately 30 s. Prepare all
solvent by running a solvent blank. The solvent blank can also
samples in this manner.
be used to check for scatter.
NOTE 8—If a micropipet with disposable plunger and tips is used,
NOTE 5—Cyclohexane can be reused, if necessary, after one or more
potential cross contamination is avoided. Otherwise, careful cleaning
distillations in an all-glass still. The distilled cyclohexane must have no
following the procedures specified in 10.1 is required.
detectable fluorescence (<2 %) in the 280 to 500-nm region of the
10. Preparation of Apparatus
spectrum when excited at 254 nm.
NOTE 6—Methylcyclohexane can also be used as a solvent, instead of
10.1 Cleaning Glassware:
cyclohexane. This is useful, particularly if the solution is needed for
10.1.1 Clean all glassware used in this procedure in the
low-temperature luminescence measurements as well.
following manner: first rinse volumetric flasks and cells three
8.6 Aluminum Foil.
times with spectroquality cyclohexane. Prior to the use of
glassware and cells throughout this procedure, rinse again with
9. Sampling and Sample Preparation
spectroquality cyclohexane.
9.1 Collect a representative sample as directed in Practice
10.1.2 If there is water present, rinse the glassware three
D4489.
times with spectroquality acetone, and then three times with
9.2 Preserve samples in containers as specified in Practice
cyclohexaneasin10.1.1.Usedetergentsonlyiftheyhavebeen
D3325. However, to avoid dewaxing, do not cool samples
checked for low fluorescence. If laboratory detergent solutions
below 5°C.
are used, repeated rinsing with Type IVreagent (see 8.3) water
9.3 Preparation of Oil Samples, as described in Practices
will be required.
D3326. Avoid the use of deasphalting procedures, if possible.
10.1.3 When working with heavy oils, a cleaning procedure
Spectroquality cyclohexane is the preferred solvent for sample
using organic solvents may not be sufficient. Heavy oils build
preparation for fluorescence.
up a residue on cells that solvent cleaning will not remove. If
9.4 Preparation of Solutions for Fluorescence Analysis—
the solvent blank shows significant impurities, a residual film
Either of the following techniques for diluting the prepared oil
on the cell, rather than an impure solvent, may be the cause.
sample with cyclohexane may be used:
Soak the cells in undiluted nitric acid for 1 h. Observe proper
9.4.1 Weighing Technique—To prepare oil solutions at a
safety precautions by using adequate eye and hand protection.
concentrationofapproximately20µg/mL,weighout0.0016 6
RinsethecellsrepeatedlywithTypeIVreagentwater,andthen
0.0001 g of oil (equivalent weight for each sample) onto a
proceed as in 10.1.2.
clean aluminum weighing pan using a micropipet. Transfer
10.2 Calibration of Spectrophotometer:
weighed oil sample into a clean 100 mL, low-actinic glass
10.2.1 Adjust and calibrate the spectrophotometer (that is,
volumetric flask by creasing the aluminum pan and washing
the emission and excitation monochromators) using a low-
the oil directly into the volumetric flask using spectroquality
pressure mercury lamp (or similar line source). Refer to
cyclohexane dispensed from a TFE-fluorocarbon wash bottle.
Practice E275 for the approved calibration method.
Dilute the solution up to volume (100 mL) and shake vigor-
11. Procedure for Recording Fluorescence Emission
ouslyseveraltimesandallowthepreparedsolutiontostandfor
Spectrum
30 min and shake again prior to performing the analysis to
11.1 Fill a clean fluorescence cell with oil solution using a
Pasteur pipet or similar techniques, taking care not to contami-
“Reagent Chemicals,American Chemical Society Specifications,”Am. Chemi-
nate the outside of the cell. Gently wipe the outside of the cell
cal Soc., Washington, DC. For suggestions on the testing of reagents not listed by
with lens paper (nonsilicone-treated) and place the cell in the
theAmerican Chemical Society, see “Analar Standards for Laboratory Chemicals,”
BDH Ltd., Poole, Dorse
...
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