1、Designation: E2143 01 (Reapproved 2013)Standard Test Method forUsing Field-Portable Fiber Optics SynchronousFluorescence Spectrometer for Quantification of FieldSamples for Aromatic and Polycyclic AromaticHydrocarbons1This standard is issued under the fixed designation E2143; the number immediately
2、following the designation indicates the year oforiginal adoption or, in the case of revision, 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. Scope1.1 This test me
3、thod covers a rapid method for the screeningof environmental samples for aromatic hydrocarbons (AHs)and polycyclic aromatic hydrocarbons (PAHs). The screeningtakes place in the field and provides immediate feedback onlimits of contamination by substances containing AHs andPAHs. Quantification is obt
4、ained by the use of appropriatelycharacterized, site-specific calibration curves. Remote sensingby use of optical fibers is useful for accessing difficult to reachareas or potentially dangerous materials or situations. Whencontamination of field personnel by dangerous materials is apossibility, use
5、of remote sensors may minimize or eliminatethe likelihood of such contamination taking place.1.2 This test method is applicable to AHs and PAHs presentin samples extracted from soils or in water. This test method isapplicable for field screening or, with an appropriatecalibration, quantification of
6、total AHs and PAHs.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, if any, associated with its use. It is theresponsibility of the user of this standar
7、d 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:2D1129 Terminology Relating to WaterD4489 Practices for Sampling of Waterborne OilsD5412 Test Method for Quantification of Complex
8、 Polycy-clic Aromatic Hydrocarbon Mixtures or Petroleum Oils inWaterE131 Terminology Relating to Molecular SpectroscopyE388 Test Method for Wavelength Accuracy and SpectralBandwidth of Fluorescence SpectrometersE578 Test Method for Linearity of Fluorescence MeasuringSystemsE579 Test Method for Limit
9、 of Detection of Fluorescence ofQuinine Sulfate in Solution3. Terminology3.1 For definitions of terms used in this test method refer toTerminology D1129 and E131.4. Summary of Test Method4.1 This test method consists of extracting the AHs andPAHs from soil samples or preparation of water samplesfoll
10、owed by synchronous fluorescence analysis with a field-portable instrument. The samples require serial dilutions ofsamples to establish a linear response. These measurements aremade using standard fluorescence cuvettes. While some opti-mization of selectivity can be accomplished by varying thewavele
11、ngth difference between excitation and emissionmonochromators, generally spectra generated from petroleumcontaminants with a wavelength difference such as 6 or 18 nmprovide good results and no preliminary spectra are required(see Test Method D5412).4.2 Different soils have varying partition coeffici
12、ents.Therefore, representative samples of a subset of the extracts orthe water samples should be analyzed by gas chromatography(GC) or other appropriate methods. The purpose is to establisha site-specific calibration curve to be used for quantification oftotal AHs and PAHs in the environmental sampl
13、es of interest.4.3 When desirable, determination of AHs and PAHs maybe made remotely using an optical fiber.1This test method is under the jurisdiction of ASTM Committee E13 onMolecular Spectroscopy and Separation Science and is the direct responsibility ofSubcommittee E13.09 on Fiber Optics, Wavegu
14、ides, and Optical Sensors.Current edition approved Jan. 1, 2013. Published January 2013. Originallyapproved in 2001. Last previous edition approved in 2006 as E2143 01 (2006)1.DOI: 10.1520/E2143-01R13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Servi
15、ce at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Significance and Use5.1 This technique is d
16、esigned for on-site rapid screeningand characterization of environmental soil and water samplesresulting in significant cost savings for environmental reme-diation projects. Remote analysis can be made with opticalfibers when situations warrant or demand use of this option.5.2 Quantification of tota
17、l AHs and PAHs in these environ-mental samples is accomplished by having a subset of thesamples analyzed by an alternate technique and generating asite-specific calibration curve.5.3 Synchronous fluorescence provides sufficient spectralinformation to characterize the AHs and PAHs present asbenzene,
18、toluene, ethylbenzene and xylene(s) (BTEX), thearomatic portion of total petroleum hydrocarbons (TPH), orlarge aromatic ring systems up to at least seven fused rings,such as might be found in creosote.6. Interferences6.1 The synchronous fluorescence spectrum can be distortedor quantification may be
19、affected if there is a contaminantpresent that produces a synchronous peak in the same vicinityas the material of interest. Often spectroquality solventscontain impurities that produce background signals. Solventblanks should be used to verify a low fluorescence backgroundso the background can be su
20、btracted from the samplesspectrum.6.2 There are naturally occurring compounds that fluoresce,which may interfere with the detection of petroleumcompounds, present in the sample. Humic acid from leaf moldis an example of such a compound. Its strongest emissionoccurs in the near ultraviolet range.6.3
21、Absorption of the exciting light by the sample itself(self-filtering effect) produces erroneous results. Analysis ofserial dilutions of the sample detects this effect and ensures anaccurate analysis is made. Once linearity is established, thenintegration of the spectrum produces accurate results.6.4
22、 Certain solvents used for extraction of the soil samplescould quench or absorb the fluorescence and raise the limit ofdetection. Care should be taken to avoid halogenated solventsor solvents containing other quenchers. The user of this testmethod should bear this in mind when selecting an appropria
23、tesolvent.NOTE 1Storage of samples in improper containers, such as plasticsother than polytetrafluoroethylene (or TFE-fluorocarbon), may result incontamination.NOTE 2This test method is normally used without an internal standarddue to possible interference by the internal standard.6.5 Certain optica
24、l fibers may generate a fluorescence back-ground. These should be avoided whenever possible. If theymust be used, a background spectrum should be generated andsubtracted from any samples measured.7. Apparatus7.1 Fluorescence SpectrometerAn instrument recordingin the spectral range of at least 250 to
25、 650 nm is required forboth excitation and emission spectrum measurements andcapable of scanning both monochromators at a constant speedwith a constant wavelength offset between them for synchro-nous scanning. The bandwidth of the monochromators shouldbe less than one half the wavelength offset betw
26、een themonochromators or smaller. The spectrometer should be ca-pable of remote sensing via optic fiber. The detector should bea photomultiplier tube or a device with similar sensitivity andresponse time. Occasionally field work requires the spectrom-eter to be battery powered. The instrument should
27、 meet thespecifications in Table 1.7.2 Excitation SourceA pulsed (9.9 W) Xenon lamp orother source having sufficient intensity throughout the ultra-violet and visible regions can be used.7.3 Cuvette Sample HolderSample holders should befabricated to hold commercially available, fluorescence-free,fus
28、ed silica cuvettes.7.4 Optical Fiber HolderA stage that allows correctpositioning of the optical fiber with respect to the emission andexcitation monochromators. The device may also be used tooptically match each fiber and the respective monochromator.7.5 Computer SystemThe instrument should be inte
29、rfacedto a computer system that is compatible with the instrumentand has suitable software for spectral data manipulation.7.6 CuvetteA standard 12 by 12 by 31 mm fluorescence-free fused silica cuvette. Four sides of the cuvette should bepolished.7.7 Optical FiberFused silica fiber (preferably a high
30、hydroxide) is required for transmission of the ultravioletwavelengths required for accurate spectroscopic analysis. Ingeneral, this material has good thermal characteristics, can beobtained with low fluorescence background, and is readilyavailable commercially.7.8 GlasswareA 10 mL and 2 mL disposabl
31、e pipet, bothmarked with 0.1 mL gradations. A glass disposable test tube,capable of holding volumes of liquid greater than 15 mL. Thetest tube caps should be polytetrafluoroethylene lined to reducepotential contamination.7.9 ScaleAportable scale capable of measuring 2 g of soilto the nearest 0.1 g.7
32、.10 CentrifugeA portable centrifuge, capable of holdingthe test tubes described in 7.8.TABLE 1 Desirable Performance Standards of a Field PortableFluorescence SpectrometerCharacteristic Desirable Range TypicalMonochromatorBandwidth 15 nm 3 nmWavelength accuracy 0.52 nm 1.0 nmReproducibility 0.1 1 %
33、0.2 %InterfaceData collection computerized laptop PCInstrument control control and dataSourceBroad band 2001000 nm Xenon lampLow-power consumption 575 W 10 WE2143 01 (Reapproved 2013)27.11 ShakerA portable shaker, capable of mixing the soiland solvent in the test tubes described in 7.8.7.12 Filter A
34、pparatusA syringe with disposable 100-mglass detachable filters.8. Reagents and Materials8.1 Purity of ReagentsSpectroquality grade reagentsshould be used in all instances unless otherwise stated.8.2 Purity of WaterASTM Grade 3 or Grade 4 watershould be used.8.3 SolventsHigh purity solvents should b
35、e used. Solventsshould be of sufficient purity so as to not generate a back-ground fluorescence spectrum when analyzed as a blank.Solvents such as hexane, cyclohexane and methylcyclohexane,ethanol, methanol, etc. must not absorb in the spectral region ofinterest.9. Sampling and Sample Preparation9.1
36、 Water SamplesCollect water samples in accordancewith Practice D4489, as applicable.9.1.1 If the water samples contain visible particles, then thesamples may be either centrifuged or filtered depending on thenature of the particles. Large, dense particles can usually becentrifuged to the bottom of t
37、he sample container, while finerparticles must be filtered. The water samples should becentrifuged in the containers in which they are sampled, inorder to avoid volatilization of the organic hydrocarbons. Thewater samples should be filtered into the cuvette for analysis.9.1.2 Add approximately 2.5 m
38、L of the water sample intothe cuvette using a disposable pipet and place the cuvette intothe instrument sample holder. The sample is ready for analysis.9.2 Soil SamplesCollect the sample using accepted proce-dures already established by ASTM Committee D18.9.2.1 Obtain a representative 2-g soil sampl
39、e from thesample container. The sample should be weighed directly in thetest tube.9.2.2 Add 10 mL of the appropriate solvent to the soilsample in the test tube using a disposable pipet.9.2.3 Shake the sample until greater than 90 % of thesample is suspended in the solvent. Follow this shaking proces
40、sby centrifuging the sample in order to separate the solvent fromthe soil.9.2.4 Pour the extract into a second test tube. At this pointsome particles may be present in the extract, thus filtration willbe required to remove them.9.2.5 If the quality check in 13.6 indicates a need foradditional extrac
41、tion, then the additional extraction will beperformed at this time.10. Preparation of Apparatus10.1 Prior to mobilization for field use, set up and calibratethe fluorescence spectrometer according to the manufacturersinstructions and Test Methods E388, E578, and E579. Once inthe field, include in th
42、e calibration procedures, a check of thewavelength accuracy of the instrument using an appropriateline-source such as a mercury lamp or xenon lamp. In addition,check the baseline of the instrument by analyzing a solventblank. Other options for calibration may include the use ofplastic standards, sea
43、led solutions of anthracene or othercommercially available standards.11. Procedure11.1 Water SamplesAnalyze the water sample over anappropriate wavelength region using a synchronous scan witha wavelength offset between the monochromators of 18 nm.Other wavelength offset between the monochromators va
44、luesmay be used when appropriate.11.1.1 Subtract the spectrum of a distilled water blank fromthe spectrum of the water sample.11.1.2 Integrate the area under the spectrum of the sampleover the appropriate wavelength region to determine therelative value.11.1.3 Determine if the sample is in the linea
45、r range. Thedetermination of linear range is done by performing a 1:1dilution. Subtract the spectrum of a distilled water blank fromthe spectrum of the 1:1 dilution. Integrate the area under thespectrum of the sample over the appropriate wavelengthregion. If the integrated value is half of the origi
46、nal value, thenthe sample is in the linear range; otherwise, perform subse-quent dilutions until the linear range is established.11.2 Soil SamplesAnalyze the soil sample extract over theappropriate wavelength region using a synchronous scan witha wavelength offset between the monochromators of 18 nm
47、.11.2.1 Subtract the spectrum of a solvent blank from thespectrum of the soil sample.11.2.2 Integrate the area under the spectrum of the sampleover the appropriate wavelength region to determine therelative value.11.2.3 Determine whether the sample is in the linear rangeaccording to 11.1.3.11.3 Quan
48、titative AnalysisAfter several soil or watersamples have been analyzed by the instrument, pick severalsamples representing a range of concentrations (at least three:high, medium, and low) and include solvent blanks andsamples of known composition. These samples should beanalyzed by the laboratory us
49、ing the appropriate method, suchas total petroleum hydrocarbons using the EnvironmentalProtection Agency (EPA), gasoline range organics (GRO), anddiesel range organics (DRO) methods or total polycyclicaromatic hydrocarbons. Many of the approved EPA methodsalso include aliphatic hydrocarbons in the analysis. If therelative proportion of aromatic hydrocarbons to aliphatichydrocarbons remains constant then the correlation graphsdescribed in 11.3.1 can be developed.11.3.1 For each sample analyzed by the laboratory, plot thelaboratory concentration
