ASTM D3414-98(2004)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D3414 – 98 (Reapproved 2004)
Standard Test Method for
Comparison of Waterborne Petroleum Oils by Infrared
Spectroscopy
This standard is issued under the fixed designation D3414; 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 3.1.1 For definitions of terms used in this test method refer
to Terminology E131 and Terminology D1129.
1.1 This test method provides a means for the identification
3.2 Definitions of Terms Specific to This Standard:
of waterborne oil samples by the comparison of their infrared
3.2.1 weathering of waterborne oil—the combined effects
spectra with those of potential source oils.
of evaporation, solution, emulsification, oxidation, biological
1.2 This test method is applicable to weathered or unweath-
decomposition, etc.
ered samples, as well as to samples subjected to simulated
weathering.
4. Summary of Test Method
1.3 This test method is written primarily for petroleum oils.
4.1 The spill sample and potential source oil(s) are treated
1.4 This test method is written for linear transmission, but
identically to put them in an appropriate form for analysis by
could be readily adapted for linear absorbance outputs.
infrared spectrophotometry.The oils are transferred to suitable
1.5 This standard does not purport to address all of the
infrared cells and the spectra are recorded from 4000 to 600
safety concerns, if any, associated with its use. It is the
−1
cm forKBrcells,andto650cm-1forHATRcellswithZnSe
responsibility of the user of this standard to establish appro-
crystals. All analyses are performed on the same instrument
priate safety and health practices and determine the applica-
usingthesamesamplecell,whichiscleanedbetweensamples.
bility of regulatory limitations prior to use. Specific precau-
The spectra of the sample and the potential source oil(s) are
tionary statements are given in Section 8.
then compared by superimposing one upon the other, looking
2. Referenced Documents at particular portions of the spectra. A high degree of coinci-
dencebetweenthespectraofthesampleandapotentialsource
2.1 ASTM Standards:
oil indicates a common origin. This test method is recom-
D1129 Terminology Relating to Water
mended for use by spectroscopists experienced in infrared oil
D1193 Specification for Reagent Water
identification or under close supervision of such qualified
D3325 PracticeforPreservationofWaterborneOilSamples
persons.
D3326 Practice for Preparation of Samples for Identifica-
tion of Waterborne Oils
5. Significance and Use
D3415 Practice for Identification of Waterborne Oils
5.1 Thistestmethodprovidesameansforthecomparisonof
E131 Terminology Relating to Molecular Spectroscopy
waterborne oil samples with potential sources.The waterborne
E168 Practices for General Techniques of Infrared Quanti-
samples may be emulsified in water or obtained from beaches,
tative Analysis
boats, oil-soaked debris, and so forth.
E275 Practice for Describing and Measuring Performance
5.2 The unknown oil is identified by the similarity of its
of Ultraviolet and Visible Spectrophotometers
infrared spectrum with that of a potential source oil obtained
3. Terminology from a known source, selected because of its possible relation-
ship to the unknown oil.
3.1 Definitions:
5.3 The analysis is capable of comparing most oils. Diffi-
culties may be encountered if a spill occurs in an already
This test method is under the jurisdiction ofASTM Committee D19 on Water
polluted area, that is, the spilled-oil mixes with another oil.
andisthedirectresponsibilityofSubcommitteeD19.06onMethodsforAnalysisfor
5.4 In certain cases, there may be interfering substances
Organic Substances in Water.
which require modification of the infrared test method or the
Current edition approved June 1, 2004. Published June 2004. Originally
approved in 1975. Last previous edition approved in 1998 as D3414–98. DOI:
use of other test methods (see Practice D3326, Method D.)
10.1520/D3414-98R04.
5.5 It is desirable, whenever possible, to apply other inde-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
pendent analytical test methods to reinforce the findings of the
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
infrared test method (see Practice D3415).
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D3414 – 98 (2004)
TABLE 1 Specifications for Infrared Spectrophotometers
6.4.6 Hot Plate.
−1
Abscissa accuracy Better than 65cm from 4000 to 2000 6.4.7 Light-Box, for viewing spectra.
−1 −1
cm range; better than 63cm
−1
from 2000 to 600 cm (or below).
−1 −1 7. Reagents
Abscissa repeatability 2.5 cm from 4000 to 2000 cm ;1.5
−1 −1
cm from 2000 to 600 cm (or below).
7.1 Purity of Reagents—Reagent grade chemicals shall be
Ordinate accuracy 6 1 % of full scale.
used in all tests unless otherwise indicated. It is intended that
Ordinate repeatability within 1 % of full scale.
all reagents shall conform to the specifications of the Commit-
tee onAnalytical Reagents of theAmerican Chemical Society,
where such specifications are available. For sample treatment
6. Apparatus
and for cleaning cells, special spectroquality reagents are
6.1 Infrared Spectrophotometer—An instrument capable
required. Other grades may be used, provided it is first
−1
of recording in the spectral range from 4000 to 600 cm and
established that the reagent is of sufficiently high purity to
meeting the specifications is shown in Table 1. Refer also to
permit its use without decreasing the accuracy of the determi-
Practice E275. Fourier transform infrared spectrophotometers
nation.
meet these specifications.
7.2 Purity of Water—Unlessotherwiseindicatedreferences
NOTE 1—Although this test method is written for the use of dispersive
towatershallbeunderstoodtomeanreagentwaterconforming
infraredspectroscopy,Fouriertransforminfraredspectroscopycanalsobe
to Specification D1193, Type II.
used for oil comparison.
7.3 Magnesium Sulfate—anhydrous, reagent grade, for dry-
6.2 Sample Cells:
ing samples.
6.2.1 Demountable Cells—The cell generally used is a
7.4 Solvents—Spectroquality solvents for sample treatment
demountable liquid cell using a 0.05-mm spacer. This cell is
and cleaning cells include cyclohexane, pentane, hexane,
usable for all oil types, the heavy oils being analyzed as methylene chloride, and methanol.
smears. For light oils, a sealed cell can be used, provided that
the sample is known to be dry. Another type used is a
8. Precautions
low-capacity demountable cell using a silver halide window
8.1 Take normal safety precautions when handling organic
with a 0.025-mm depression. Satisfactory oil spectra can be
solvents.Takeprecautionstoensurethatwetoilsamplesdonot
obtained with this cell with as little as 10 µL of oil, compared
come in contact with water-soluble cell window materials.
to the nearly 100 µL required for the standard cells. This cell
Most spectrophotometers require humidity control (to about
can also be used to screen for the presence of water in oil
45%), particularly if they have humidity-sensitive detectors
samples.
such as those with cesium iodide optics. The primary precau-
6.2.2 Horizontal Attentuated Reflectance Apparatus
tion which must be taken to provide the best possible results is
(HATR), may be used instead of demountable cells. If so, all
that all samples analyzed should be treated in an identical
analyses must be performed with the same HATR apparatus.
fashion, run in the same cell, on the same instrument and
6.3 Cell Windows:
preferably on the same day by the same operator.
6.3.1 Potassium or silver bromide should be used for
NOTE 3—If the samples cannot be analyzed the same day, one of the
demountable cells. Silver chloride may be substituted for the
first samples must be repeated to ensure that the spectra are not
bromide.
significantly different.
NOTE 2—Sodium chloride should not be used; results obtained using
9. Sampling
thiswindowmaterial,althoughconsistentwitheachother,arenotdirectly
comparable to those from the other window materials. Sodium chloride
9.1 On-Scene—A representative sample of the waterborne
was shown by Brown, et al to give results significantly different from
oil is collected in a glass jar (precleaned with cyclohexane and
those obtained with potassium bromide or silver chloride, based on
dried) having a TFE-fluorocarbon-lined cap. In the same time
quantitative comparisons.
frame, samples are collected of potential source samples that
6.3.2 Zinc selenide is the material of choice for the HATR
are to be compared to the waterborne sample.
apparatus.
9.2 Laboratory—See Annex A1.
6.4 Accessories:
6.4.1 Reference Beam Attenuator, for setting baseline with
10. Preservation of Sample
the low-capacity silver halide cell.
10.1 Refer to Practice D3325.
6.4.2 Disposable Pasteur Pipets and Hypodermic Syringes.
6.4.3 Window-Polishing Kit.
11. Analytical Procedures
6.4.4 Centrifuge.
11.1 Recording Spectra for Dispersive Instruments:
6.4.5 Vortex Mixer.
Consult the manufacturer’s operating manual for specific instructions on using
this apparatus. “Reagent Chemicals, American Chemical Society Specifications,” American
TheMini-cellmadebyWilksScientificCorp.,S.Norwalk,CT,hasbeenfound Chemical Society, Washington, DC. For suggestions on the testing of reagents not
to be satisfactory for this purpose. listed by the American Chemical Society, see Rosin, J.,“ Reagent Chemicals and
Brown, C.W., Lynch, P. F., andAhmadjian, M. “Identification of Oil Slicks by Standards,” D. Van Nostrand Co., New York, NY, and the “United States
Infrared Spectroscopy,” NTIS Accession No. ADA 040975, 1976. Pharmacopeia”.
D3414 – 98 (2004)
FIG. 1 Complete Spectrum of a No. 2 Fuel Oil, Analyzed in Triplicate
11.1.1 Operatetheinstrumentinaccordancewiththemanu- 12. Interpretation of Spectra
facturer’s instructions. Refer to Practices E168 for more
12.1 Ultimately, oil identification is based on a peak-by-
information on handling cells.
peakcomparisonofthespillspectrumwiththoseofthevarious
11.1.2 Check the calibration daily by scanning a 0.05-mm
potential sources.Alight-box is convenient for superimposing
polystyrene film in accordance with Practice E275. Observe
these spectra. When the results are to be used for forensic
whether the test spectra are within the limits of the instrument
purposes, comparisons must be made on spectra obtained by
specifications. This calibration check should be performed
using the same sample preparation, sample cell, and the same
beforeeveryoilspillsetandthespectrumretainedwithspectra
instrumental conditions, preferably with the same operator on
from the spill and suspects as part of the case record.
the same day.
11.1.3 Test the resolution by observing the sidebands in the
12.2 Sample Spectra
−1
polystyrenespectrumat2850.7and1583.1cm whichshould
12.2.1 Fig.1showstheinfraredspectrumofaNo.2fueloil
be distinct and well defined. This is also true for the sideband
to illustrate the general spectral characteristics of an oil
−1
at 3100 cm which should have a clear inflection with a
analyzed by infrared transmission through KBr windows. This
displacement of at least 1 to 3% T where T=transmittance.
particular illustration is actually a superposition of three
11.1.4 Place the sample in a liquid cell (see Annex A2 or
independent spectra which graphically show how reproducible
Annex A3) and insert cell into the infrared beam. Set the
−1 the triplicates are, even with a demountable cell, if proper
absorbance to read 0.02 A (95% T) at 1975 620 cm .
techniques are used. The “oil fingerprint” region between 900
−1
NOTE 4—The absorbance is set at a fixed value so that the resultant
to 700 cm can be seen to have a large amount of fine detail
spectra can be compared from a common baseline.
characteristic of a light oil.
−1 −1
11.1.5 Scan the spectrum from 4000 to 600 cm using 12.2.2 Figs. 2-5 show spectra from 2000 to 600 cm for
normal operating conditions and slit settings. four oils weathered over 4 days.They show the general effects
−1
11.2 FTIR Instruments: of weathering on baselines between 1300 and 900 cm and
11.2.1 Collectdatafromabackgroundscan(aironly)under relativechangesofindividualpeaksinthe“fingerprint”region.
conditions identical to those under which the sample will be The figures are, respectively: No. 2, No. 4, No. 6 fuel oils, and
run, that is, with the cell in the instrument and all instrument
a Louisiana crude with curves at 0, 1, 2, 3, and 4 days outdoor
parameters the same. weathering.
11.2.2 Normalize the absorbance before comparing the
12.2.3 Fig. 6 and Fig. 7 show details of weathering of
spectra.
various oil types as described in 12.3.7.
11.2.3 Collect data from 650 cm-1 for HATR cells with
12.3 Overlay Method:
ZnSe, due to the sprectral absorbance cutoff for ZnSe.
12.3.1 The overlay method consists of a visual comparison
11.3 Preparation of Sample—Refer toAnnexA1 and Prac-
of the spectrum of a spill with that of a potential source in the
tice D3326 for sample preparation.
sequence as follows and outlined in Fig. 8. This may be
accomplished using a light-box or even recording two spectra
NOTE 5—Theprimaryobjectiveinsamplepreparationistheremovalof
water to protect the sample cells and get a “clean” spectrum of the oil. If on the same chart.
at all possible, the use of solvent should be avoided. It is sometimes
12.3.1.1 First ensure that the spectra have comparable
necessary to use solvent in order to break refractory emulsions or to −1
baselines at 1975 cm , that is, that they were set at an
extract the oil from solid substrates. It must be remembered that for valid
absorbance of 0.02 (95% T).
comparisons of spectra, both oils being compared must have been
−1
12.3.1.2 Next, examine the absorbance at 1377 cm to
prepared the same way, that is, if one is deasphalted with pentane, the
othermustbealso(seePracticesD3326forthedeasphaltingprocedure.It obtain qualitative assurance that the samples were analyzed at
should be noted that 15 parts of solvent (versus 40) is all that is necessary
the same thickness, that is, same cell path length (see 12.3.2).
for quantitative precipitation of the asphaltene fraction.)
12.3.1.3 Then examine the curve for overall similarities in
−1
shape from 4000 to 600 cm . For petroleum oils, the baseline
will tend to move downward with weathering (to higher
Tables of Wavenumbers Fo
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