1、Designation: D3414 98 (Reapproved 2011)1Standard Test Method forComparison of Waterborne Petroleum Oils by InfraredSpectroscopy1This standard is issued under the fixed designation D3414; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisi
2、on, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEThis test method received editorial corrections in 20111. Scope1.1 This test method provides a means for the
3、identificationof waterborne oil samples by the comparison of their infraredspectra with those of potential source oils.1.2 This test method is applicable to weathered or unweath-ered samples, as well as to samples subjected to simulatedweathering.1.3 This test method is written primarily for petrole
4、um oils.1.4 This test method is written for linear transmission, butcould be readily adapted for linear absorbance outputs.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro
5、-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific precau-tionary statements are given in Section 8.2. Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD3325 Practice for
6、 Preservation of Waterborne Oil SamplesD3326 Practice for Preparation of Samples for Identifica-tion of Waterborne OilsD3415 Practice for Identification of Waterborne OilsE131 Terminology Relating to Molecular SpectroscopyE168 Practices for General Techniques of Infrared Quanti-tative AnalysisE275 P
7、ractice for Describing and Measuring Performanceof Ultraviolet and Visible Spectrophotometers3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method referto Terminology E131 and Terminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 weathering of wat
8、erborne oilthe combined effectsof evaporation, solution, emulsification, oxidation, biologicaldecomposition, etc.4. Summary of Test Method4.1 The spill sample and potential source oil(s) are treatedidentically to put them in an appropriate form for analysis byinfrared spectrophotometry. The oils are
9、 transferred to suitableinfrared cells and the spectra are recorded from 4000 to 600cm-1for KBr cells, and to 650 cm-1for HATR cells with ZnSecrystals. All analyses are performed on the same instrumentusing the same sample cell, which is cleaned between samples.The spectra of the sample and the pote
10、ntial source oil(s) arethen compared by superimposing one upon the other, lookingat particular portions of the spectra. A high degree of coinci-dence between the spectra of the sample and a potential sourceoil indicates a common origin. This test method is recom-mended for use by spectroscopists exp
11、erienced in infrared oilidentification or under close supervision of such qualifiedpersons.5. Significance and Use5.1 This test method provides a means for the comparison ofwaterborne oil samples with potential sources. The waterbornesamples may be emulsified in water or obtained from beaches,boats,
12、 oil-soaked debris, and so forth.5.2 The unknown oil is identified by the similarity of itsinfrared spectrum with that of a potential source oil obtainedfrom a known source, selected because of its possible relation-ship to the unknown oil.1This test method is under the jurisdiction of ASTM Committe
13、e D19 on Waterand is the direct responsibility of Subcommittee D19.06 on Methods forAnalysis forOrganic Substances in Water.Current edition approved June 15, 2011. Published July 2011. Originallyapproved in 1975. Last previous edition approved in 2004 as D341498(2004).DOI: 10.1520/D3414-11.2For refe
14、renced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, Wes
15、t Conshohocken, PA 19428-2959, United States.5.3 The analysis is capable of comparing most oils. Diffi-culties may be encountered if a spill occurs in an alreadypolluted area, that is, the spilled-oil mixes with another oil.5.4 In certain cases, there may be interfering substanceswhich require modif
16、ication of the infrared test method or theuse of other test methods (see Practice D3326, Method D.)5.5 It is desirable, whenever possible, to apply other inde-pendent analytical test methods to reinforce the findings of theinfrared test method (see Practice D3415).6. Apparatus6.1 Infrared Spectropho
17、tometerAn instrument3capableof recording in the spectral range from 4000 to 600 cm1andmeeting the specifications is shown in Table 1. Refer also toPractice E275. Fourier transform infrared spectrophotometersmeet these specifications.NOTE 1Although this test method is written for the use of dispersiv
18、einfrared spectroscopy, Fourier transform infrared spectroscopy can also beused for oil comparison.6.2 Sample Cells:6.2.1 Demountable CellsThe cell generally used is ademountable liquid cell using a 0.05-mm spacer. This cell isusable for all oil types, the heavy oils being analyzed assmears. For lig
19、ht oils, a sealed cell can be used, provided thatthe sample is known to be dry. Another type used is alow-capacity demountable cell using a silver halide windowwith a 0.025-mm depression.4Satisfactory oil spectra can beobtained with this cell with as little as 10 L of oil, comparedto the nearly 100
20、L required for the standard cells. This cellcan also be used to screen for the presence of water in oilsamples.6.2.2 Horizontal Attentuated Reflectance Apparatus(HATR), may be used instead of demountable cells. If so, allanalyses must be performed with the same HATR apparatus.6.3 Cell Windows:6.3.1
21、Potassium or silver bromide should be used fordemountable cells. Silver chloride may be substituted for thebromide.NOTE 2Sodium chloride should not be used; results obtained usingthis window material, although consistent with each other, are not directlycomparable to those from the other window mate
22、rials. Sodium chloridewas shown by Brown, et al5to give results significantly different fromthose obtained with potassium bromide or silver chloride, based onquantitative comparisons.6.3.2 Zinc selenide is the material of choice for the HATRapparatus.6.4 Accessories:6.4.1 Reference Beam Attenuator,
23、for setting baseline withthe low-capacity silver halide cell.6.4.2 Disposable Pasteur Pipets and Hypodermic Syringes.6.4.3 Window-Polishing Kit.6.4.4 Centrifuge.6.4.5 Vortex Mixer.6.4.6 Hot Plate.6.4.7 Light-Box, for viewing spectra.7. Reagents7.1 Purity of ReagentsReagent grade chemicals shall beus
24、ed in all tests unless otherwise indicated. It is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.6For sample treatmentand for cleaning cells, special spectroquality reagen
25、ts arerequired. Other grades may be used, provided it is firstestablished that the reagent is of sufficiently high purity topermit its use without decreasing the accuracy of the determi-nation.7.2 Purity of Water Unless otherwise indicated referencesto water shall be understood to mean reagent water
26、 conformingto Specification D1193, Type II.7.3 Magnesium Sulfateanhydrous, reagent grade, for dry-ing samples.7.4 SolventsSpectroquality solvents for sample treatmentand cleaning cells include cyclohexane, pentane, hexane,methylene chloride, and methanol.8. Precautions8.1 Take normal safety precauti
27、ons when handling organicsolvents.Take precautions to ensure that wet oil samples do notcome in contact with water-soluble cell window materials.Most spectrophotometers require humidity control (to about45 %), particularly if they have humidity-sensitive detectorssuch as those with cesium iodide opt
28、ics. The primary precau-tion which must be taken to provide the best possible results isthat all samples analyzed should be treated in an identicalfashion, run in the same cell, on the same instrument andpreferably on the same day by the same operator.NOTE 3If the samples cannot be analyzed the same
29、 day, one of thefirst samples must be repeated to ensure that the spectra are notsignificantly different.9. Sampling9.1 On-SceneA representative sample of the waterborneoil is collected in a glass jar (precleaned with cyclohexane anddried) having a TFE-fluorocarbon-lined cap. In the same time3Consul
30、t the manufacturers operating manual for specific instructions on usingthis apparatus.4The Mini-cell made by Wilks Scientific Corp., S. Norwalk, CT, has been foundto be satisfactory for this purpose.5Brown, C. W., Lynch, P. F., and Ahmadjian, M. “Identification of Oil Slicks byInfrared Spectroscopy,
31、” NTIS Accession No. ADA 040975, 1976.6“Reagent Chemicals, American Chemical Society Specifications,” AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Rosin, J.,“ Reagent Chemicals andStandards,” D. Van Nostrand Co.,
32、 New York, NY, and the “United StatesPharmacopeia”.TABLE 1 Specifications for Infrared SpectrophotometersAbscissa accuracy Better than 6 5cm1from 4000 to 2000cm1range; better than 6 3cm1from 2000 to 600 cm1(or below).Abscissa repeatability 2.5 cm1from 4000 to 2000 cm1;1.5cm1from 2000 to 600 cm1(or b
33、elow).Ordinate accuracy 6 1 % of full scale.Ordinate repeatability within 1 % of full scale.D3414 98 (2011)12frame, samples are collected of potential source samples thatare to be compared to the waterborne sample.9.2 LaboratorySee Annex A1.10. Preservation of Sample10.1 Refer to Practice D3325.11.
34、Analytical Procedures11.1 Recording Spectra for Dispersive Instruments:11.1.1 Operate the instrument in accordance with the manu-facturers instructions. Refer to Practices E168 for moreinformation on handling cells.11.1.2 Check the calibration daily by scanning a 0.05-mmpolystyrene film in accordanc
35、e with Practice E275. Observewhether the test spectra are within the limits of the instrumentspecifications. This calibration check should be performedbefore every oil spill set and the spectrum retained with spectrafrom the spill and suspects as part of the case record.11.1.3 Test the resolution by
36、 observing the sidebands in thepolystyrene spectrum at 2850.7 and 1583.1 cm1which shouldbe distinct and well defined.7This is also true for the sidebandat 3100 cm1which should have a clear inflection with adisplacement of at least 1 to 3 % T where T = transmittance.11.1.4 Place the sample in a liqui
37、d cell (see Annex A2 orAnnex A3) and insert cell into the infrared beam. Set theabsorbance to read 0.02 A (95 % T) at 1975 6 20 cm1.NOTE 4The absorbance is set at a fixed value so that the resultantspectra can be compared from a common baseline.11.1.5 Scan the spectrum from 4000 to 600 cm1usingnorma
38、l operating conditions and slit settings.11.2 FTIR Instruments:11.2.1 Collect data from a background scan (air only) underconditions identical to those under which the sample will berun, that is, with the cell in the instrument and all instrumentparameters the same.11.2.2 Normalize the absorbance be
39、fore comparing thespectra.11.2.3 Collect data from 650 cm-1for HATR cells withZnSe, due to the sprectral absorbance cutoff for ZnSe.11.3 Preparation of SampleRefer to Annex A1 and Prac-tice D3326 for sample preparation.NOTE 5The primary objective in sample preparation is the removal ofwater to prote
40、ct the sample cells and get a “clean” spectrum of the oil. Ifat all possible, the use of solvent should be avoided. It is sometimesnecessary to use solvent in order to break refractory emulsions or toextract the oil from solid substrates. It must be remembered that for validcomparisons of spectra, b
41、oth oils being compared must have beenprepared the same way, that is, if one is deasphalted with pentane, theother must be also (see Practices D3326 for the deasphalting procedure. Itshould be noted that 15 parts of solvent (versus 40) is all that is necessaryfor quantitative precipitation of the as
42、phaltene fraction.)12. Interpretation of Spectra12.1 Ultimately, oil identification is based on a peak-by-peak comparison of the spill spectrum with those of the variouspotential sources. A light-box is convenient for superimposingthese spectra. When the results are to be used for forensicpurposes,
43、comparisons must be made on spectra obtained byusing the same sample preparation, sample cell, and the sameinstrumental conditions, preferably with the same operator onthe same day.12.2 Sample Spectra12.2.1 Fig. 1 shows the infrared spectrum of a No. 2 fuel oilto illustrate the general spectral char
44、acteristics of an oilanalyzed by infrared transmission through KBr windows. Thisparticular illustration is actually a superposition of threeindependent spectra which graphically show how reproduciblethe triplicates are, even with a demountable cell, if propertechniques are used. The “oil fingerprint
45、” region between 900to 700 cm1can be seen to have a large amount of fine detailcharacteristic of a light oil.12.2.2 Figs. 2-5 show spectra from 2000 to 600 cm1forfour oils weathered over 4 days. They show the general effectsof weathering on baselines between 1300 and 900 cm1andrelative changes of in
46、dividual peaks in the“ fingerprint” region.The figures are, respectively: No. 2, No. 4, No. 6 fuel oils, anda Louisiana crude with curves at 0, 1, 2, 3, and 4 days outdoorweathering.12.2.3 Fig. 6 and Fig. 7 show details of weathering ofvarious oil types as described in 12.3.7.12.3 Overlay Method:12.
47、3.1 The overlay method consists of a visual comparisonof the spectrum of a spill with that of a potential source in thesequence as follows and outlined in Fig. 8. This may beaccomplished using a light-box or even recording two spectraon the same chart.7Tables of Wavenumbers For The Calibration of In
48、frared Spectrometers,IUPAC, Commission on Molecular Structure and Spectroscopy, Butterworth andCo., Toronto, Canada, 1961.FIG. 1 Complete Spectrum of a No. 2 Fuel Oil, Analyzed in TriplicateD3414 98 (2011)1312.3.1.1 First ensure that the spectra have comparablebaselines at 1975 cm1, that is, that th
49、ey were set at anabsorbance of 0.02 (95 % T).12.3.1.2 Next, examine the absorbance at 1377 cm1toobtain qualitative assurance that the samples were analyzed atthe same thickness, that is, same cell path length (see 12.3.2).12.3.1.3 Then examine the curve for overall similarities inshape from 4000 to 600 cm1. For petroleum oils, the baselinewill tend to move downward with weathering (to higherabsorbance between 1350 to 900 cm1) but with little relativechange of the peaks in that range.12.3.1.4 Examine the 1770 to 1685 cm1region to deter-mi
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