1、Designation: D3650 93 (Reapproved 2011)Standard Test Method forComparison of Waterborne Petroleum Oils ByFluorescence Analysis1This standard is issued under the fixed designation D3650; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, 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.1. Scope*1.1 This test method covers the comparison of waterbornepetroleum oils with oils from possible sources by
3、means offluorescence spectroscopy (1).2Useful references for this testmethod include: (2) and (3) for fluorescence analysis in generaland (4), (5), and (6) for oil spill identification includingfluorescence.1.2 This test method is applicable to crude or refinedpetroleum products, for any sample of n
4、eat oil, waterborne oil,or sample of oil-soaked material. Unless the samples arecollected soon after the spill occurs, it is not recommended thatvolatile fuels such as gasoline, kerosine, and No. 1 fuel oils beanalyzed by this test method, because their fluorescencesignatures change rapidly with wea
5、thering. Some No. 2 fueloils and light crude oils may only be identifiable up to 2 daysweathering, or less, depending on the severity of weathering. Ingeneral, samples weathered up to 1 week may be identified,although longer periods of weathering may be tolerated forheavy residual oils, oil weathere
6、d under Arctic conditions, oroil that has been protected from weathering by collecting in athick layer.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns,
7、if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D1129 Terminology Relating to WaterD1193 Spec
8、ification for Reagent WaterD3325 Practice for Preservation of Waterborne Oil SamplesD3326 Practice for Preparation of Samples for Identifica-tion of Waterborne OilsD3415 Practice for Identification of Waterborne OilsD4489 Practices for Sampling of Waterborne OilsE131 Terminology Relating to Molecula
9、r SpectroscopyE275 Practice for Describing and Measuring Performanceof Ultraviolet and Visible SpectrophotometersE520 Practice for Describing Photomultiplier Detectors inEmission and Absorption Spectrometry3. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod refer to Termino
10、logy D1129, Practice D3415, andTerminology E131.4. Summary of Test Method4.1 This test method consists of fluorescence analyses ofdilute solutions of oil in spectroquality cyclohexane. In mostcases the emission spectra, with excitation at 254 nm, over thespectral range from 280 to 500 nm, are adequa
11、te for matching.4.2 Identification of the sample is made by direct visualcomparison of the samples spectrum with the spectra frompossible source samples.NOTE 1When weathering has occurred, it may be necessary toconsider known weathering trends when matching spectra (Fig. 1 and Fig.2).1This test meth
12、od is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.06 on Methods forAnalysis forOrganic Substances in Water.Current edition approved May 1, 2011. Published June 2011. Originallyapproved in 1978. Last previous edition approved in 2006 as D3
13、650 93 (2006).DOI: 10.1520/D3650-93R11.2The boldface numbers in parentheses refer to the references at the end of thistest method.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informat
14、ion, refer to the standards Document Summary page onthe ASTM website.1*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.5. Significance and Use5.1 This test method is use
15、ful for rapid identification ofwaterborne petroleum oil samples as well as oil samplesobtained from fuel or storage tanks, or from sand, vegetation,or other substrates. This test method is applicable to weatheredand unweathered neat oil samples.5.2 The unknown oil is identified through the compariso
16、n ofthe fluorescence spectrum of the oil with the spectra (obtainedat similar instrumental settings on the same instrument) ofpossible source samples. A match of the entire spectrumbetween the unknown and possible source sample indicates acommon source.6. Interferences6.1 The fluorescence spectrum w
17、ill be distorted if an oilsample has been contaminated by an appreciable amount, forexample, 1 % of common chemical impurities such as otheroils that are fluorescent on excitation at 254 nm.NOTE 2Storage of samples in improper containers (for example,plastics) may result in contamination. This inter
18、ference can be eliminatedby observing proper procedures for collection and preservation ofsamples. Refer to Practice D3325.NOTE 3“Spectroquality” cyclohexane may not have a low enoughfluorescence solvent blank. Lots vary in the content of fluorescentimpurities, which may increase with storage time e
19、ven if the bottle isunopened.6.2 Oil residues may build up in fluorescence cells particu-larly after prolonged usage with heavy oils. In such a case,follow the procedure using nitric acid for cleaning glassware(10.1.3).6.3 Possible interferences from Raman or RayleighTyndallscattering are not observ
20、ed in the emission scan rangesselected.7. Apparatus7.1 Fluorescence Spectrophotometer (or Spectro-fluorometer)An instrument recording in the spectral range of220 nm to at least 600 nm for both excitation and emissionresponses and capable of meeting the specifications stated inTable 1.7.2 Excitation
21、SourceA high-pressure xenon lamp (a150-W xenon lamp has proven acceptable). Other continuumsources, such as deuterium or high-pressure xenon-mercury,which have sufficient intensity in the ultraviolet region, couldbe used as excitation sources.NOTE 4Line sources such as a low-pressure mercury lamp ma
22、y alsobe used for excitation at 254 nm, if the flexibility of using arbitraryexcitation wavelengths or excitation spectra is not desired and if sourceintensity is adequate.7.3 Fluorescence CellsStandard cells, made fromfluorescence-free fused silica with a pathlength of 10 mm anda height of 45 mm.7.
23、4 Recorder or ComputerStrip chart or X-Y recorder,with a response time less than 1 s for full-scale deflection, or acomputer capable of digitizing the data at a rate of 1 data pointper nanometre.7.5 Cell-Filling DeviceDisposable Pasteur capillary pi-pet.7.6 Volumetric FlasksLow-actinic glass, ground
24、-glassstoppered volumetric flasks (100-mL).7.7 Micropipet, 10 to 50-L capacity.7.8 Analytical Balance, with a precision of at least 60.1 mg.FIG. 1 Fluorescence Spectra for a Typical No. 2 Fuel Oil(Unweathered and Weathered One Day)FIG. 2 Fluorescence Spectra for a Typical No. 6 Fuel Oil(Unweathered
25、and Weathered One Day)TABLE 1 Specifications for Fluorescence SpectrophotometersWavelength ReproducibilityExcitation monochromator better than6 2nmEmission monochromator better than 62nmGratings (Typical Values)Excitation monochromator minimum of 600 lines/mm blazed at300 nmAEmission monochromator m
26、inimum of 600 lines/mm blazed at300 nm or 500 nmAPhotomultiplier TubeBEither S-20Cor S-5DResponseEResolutionExcitation monochromator better than 2 nmEmission monchromator better than 2 nmTime Constantnot to exceed one secondAOr designed to have a good efficiency in this spectral region.BSee Practice
27、 E520.CPhotomultiplier tubes such as Hamamatsu R-446-UR.DPhotomultiplier tubes such as RCA 1P28 or Hamamatsu R-106.EOr equivalent having a good spectral response in the spectral region from 280to 600 nm.D3650 93 (2011)27.9 Weighing Pans, 5 to 7-mm diameter, 18 mm deep, madeof aluminum or equivalent.
28、7.10 Test Tubes, disposable 15-mL glass test tubes.7.11 Micropipet, or microsyringe, 9-L capacity; with anaccuracy of 1 % and reproducibility of 0.1 % of pipet capacity.7.12 Micropipet, 200-L capacity with disposable tips; withan accuracy of 1 % and reproducibility of 0.1 % of pipettorcapacity.7.13
29、Solvent Dispenser, adjustable to deliver 10 mL.7.14 Vortex Mixer.8. Reagents and Materials8.1 Purity of ReagentsSpectroquality grade reagentsshould be used in all instances unless otherwise stated. It isintended that all reagents shall conform to the specifications ofthe Committee onAnalytical Reage
30、nts of theAmerican Chemi-cal Society, where such specifications are available.48.2 Purity of Water References to water shall be under-stood to mean Type IV reagent water conforming to Specifi-cation D1193. However, since fluorescent organic impurities inthe water may constitute an interference, the
31、purity of the watershould be checked by running a water blank using the sameinstrument conditions as for the solvent blank.8.3 Acetone (CH3COCH3).8.4 Nitric Acid (sp gr 1.42)Concentrated nitric acid(HNO3).8.5 Cyclohexane, spectroquality grade, with a fluorescencesolvent blank less than 2 % of the in
32、tensity of the major peakof the sample fluorescence generated with the same instrumen-tal settings over the emission range used. Cyclohexane isdispensed throughout the procedure from a 500-mL TFE-fluorocarbon wash bottle. For prolonged storage, cyclohexaneshould be stored only in glass. Check the su
33、itability of thesolvent by running a solvent blank. The solvent blank can alsobe used to check for scatter.NOTE 5Cyclohexane can be reused, if necessary, after one or moredistillations in an all-glass still. The distilled cyclohexane must have nodetectable fluorescence (2 %) in the 280 to 500-nm reg
34、ion of thespectrum when excited at 254 nm.NOTE 6Methylcyclohexane can also be used as a solvent, instead ofcyclohexane. This is useful, particularly if the solution is needed forlow-temperature luminescence measurements as well.8.6 Aluminum Foil.9. Sampling and Sample Preparation9.1 Collect a repres
35、entative sample as directed in PracticeD4489.9.2 Preserve samples in containers as specified in PracticeD3325. However, to avoid dewaxing, do not cool samplesbelow 5C.9.3 Preparation of Oil Samples, as described in PracticesD3326. Avoid the use of deasphalting procedures, if possible.Spectroquality
36、cyclohexane is the preferred solvent for samplepreparation for fluorescence.9.4 Preparation of Solutions for Fluorescence AnalysisEither of the following techniques for diluting the prepared oilsample with cyclohexane may be used:9.4.1 Weighing TechniqueTo prepare oil solutions at aconcentration of
37、approximately 20 g/mL, weigh out 0.0016 60.0001 g of oil (equivalent weight for each sample) onto aclean aluminum weighing pan using a micropipet. Transferweighed oil sample into a clean 100 mL, low-actinic glassvolumetric flask by creasing the aluminum pan and washingthe oil directly into the volum
38、etric flask using spectroqualitycyclohexane dispensed from a TFE-fluorocarbon wash bottle.Dilute the solution up to volume (100 mL) and shake vigor-ously several times and allow the prepared solution to stand for30 min and shake again prior to performing the analysis toensure that all oil dissolves.
39、 Occasionally, depending onfluorescence yield of the oil tested and instrumentation used, itmay be necessary to use 100 ppm concentration to get adequatefluorescence intensity. In these cases, weigh out 0.0078 60.0001 g of oil and proceed as above.NOTE 7It is preferable that the prepared solution be
40、 used the sameday. Do not use solutions that have been standing for periods in excess of6 h unless they have been refrigerated. In no case use solutions more than2 days old.9.4.2 Volume TechniqueAllow the prepared oil sample tocome to room temperature and shake until they are homoge-neous. Transfer
41、9 L of the oil to a 15-mL disposable glass testtube with a micropipet or microsyringe and add 10 mL ofspectroquality cyclohexane with a solvent dispenser. Place acap of aluminum foil over the top of the test tube and vortex forapproximately 30 s. With a micropipet, transfer 200 L of thissolution to
42、a second 15-mL test tube and then add 10 mL ofcyclohexane. Place a cap of aluminum foil over the top of thesecond test tube and vortex for approximately 30 s. Prepare allsamples in this manner.NOTE 8If a micropipet with disposable plunger and tips is used,potential cross contamination is avoided. Ot
43、herwise, careful cleaningfollowing the procedures specified in 10.1 is required.10. Preparation of Apparatus10.1 Cleaning Glassware:10.1.1 Clean all glassware used in this procedure in thefollowing manner: first rinse volumetric flasks and cells threetimes with spectroquality cyclohexane. Prior to t
44、he use ofglassware and cells throughout this procedure, rinse again withspectroquality cyclohexane.10.1.2 If there is water present, rinse the glassware threetimes with spectroquality acetone, and then three times withcyclohexane as in 10.1.1. Use detergents only if they have beenchecked for low flu
45、orescence. If laboratory detergent solutionsare used, repeated rinsing with Type IV reagent (see 8.3) waterwill be required.10.1.3 When working with heavy oils, a cleaning procedureusing organic solvents may not be sufficient. Heavy oils buildup a residue on cells that solvent cleaning will not remo
46、ve. Ifthe solvent blank shows significant impurities, a residual filmon the cell, rather than an impure solvent, may be the cause.Soak the cells in undiluted nitric acid for 1 h. Observe proper4“Reagent Chemicals, American Chemical Society Specifications,” Am. Chemi-cal Soc., Washington, DC. For sug
47、gestions on the testing of reagents not listed bythe American Chemical Society, see “Analar Standards for Laboratory Chemicals,”BDH Ltd., Poole, Dorset, U.K., and the “United States Pharmacopeia.”D3650 93 (2011)3safety precautions by using adequate eye and hand protection.Rinse the cells repeatedly
48、with Type IV reagent water, and thenproceed as in 10.1.2.10.2 Calibration of Spectrophotometer:10.2.1 Adjust and calibrate the spectrophotometer (that is,the emission and excitation monochromators) using a low-pressure mercury lamp (or similar line source). Refer toPractice E275 for the approved cal
49、ibration method.11. Procedure for Recording Fluorescence EmissionSpectrum11.1 Fill a clean fluorescence cell with oil solution using aPasteur pipet or similar techniques, taking care not to contami-nate the outside of the cell. Gently wipe the outside of the cellwith lens paper (nonsilicone-treated) and place the cell in thesample compartment.11.2 Set the excitation monochromator at 254 nm.11.3 Set the slit width of the excitation monochromatorbetween 5 and 35 nm depending on the intensity required.E131-nm slit width is recommended. Set the emission sl
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