1、Designation: D5412 93 (Reapproved 2017)1Standard Test Method forQuantification of Complex Polycyclic Aromatic HydrocarbonMixtures or Petroleum Oils in Water1This standard is issued under the fixed designation D5412; the number immediately following the designation indicates the year oforiginal adopt
2、ion 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.1NOTEWarning statements were editorially corrected throughout in December 2017.1. Sco
3、pe1.1 This test method covers a means for quantifying orcharacterizing total polycyclic aromatic hydrocarbons (PAHs)by fluorescence spectroscopy (Fl) for waterborne samples. Thecharacterization step is for the purpose of finding an appropri-ate calibration standard with similar emission and synchron
4、ousfluorescence spectra.1.2 This test method is applicable to PAHs resulting frompetroleum oils, fuel oils, creosotes, or industrial organicmixtures. Samples can be weathered or unweathered, but eitherthe same material or appropriately characterized site-specificPAH or petroleum oil calibration stan
5、dards with similar fluo-rescence spectra should be chosen. The degree of spectralsimilarity needed will depend on the desired level of quantifi-cation and on the required data quality objectives.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are includ
6、ed 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 standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limit
7、ations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization
8、TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3325 Practice for Preservation of W
9、aterborne Oil SamplesD3326 Practice for Preparation of Samples for Identificationof Waterborne OilsD3415 Practice for Identification of Waterborne OilsD3650 Test Method for Comparison of Waterborne Petro-leum Oils By Fluorescence AnalysisD4489 Practices for Sampling of Waterborne OilsD4657 Test Meth
10、od for PolynuclearAromatic Hydrocarbonsin Water (Withdrawn 2005)3E131 Terminology Relating to Molecular SpectroscopyE169 Practices for General Techniques of Ultraviolet-VisibleQuantitative AnalysisE275 Practice for Describing and Measuring Performance ofUltraviolet and Visible SpectrophotometersE388
11、 Test Method for Wavelength Accuracy and SpectralBandwidth of Fluorescence SpectrometersE578 Test Method for Linearity of Fluorescence MeasuringSystemsE579 Test Method for Limit of Detection of Fluorescence ofQuinine Sulfate in Solution1This test method is under the jurisdiction of ASTM Committee D1
12、9 on Waterand is the direct responsibility of Subcommittee D19.06 on Methods forAnalysis forOrganic Substances in Water.Current edition approved Dec. 15, 2017. Published January 2018. Originallyapproved in 1993. Last previous edition approved in 2011 as D5412 93 (2011)1.DOI: 10.1520/D5412-93R17E01.2
13、For referenced 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.3The last approved version of this historical standard is refe
14、renced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for t
15、heDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard, refer toTerminology D1129, Terminology E131, and Practice D3415
16、.4. Summary of Test Method4.1 This test method consists of fluorescence analysis ofdilute solutions of PAHs or petroleum oils in appropriatesolvents (spectroquality solvents such as cyclohexane or otherappropriate solvents, for example, ethanol, depending onpolarity considerations of the sample). Th
17、e test method re-quires an initial qualitative characterization step involving bothfluorescence emission and synchronous spectroscopy in orderto select appropriate calibration standards with similar fluores-cence spectra as compared to the samples (see Annex A1 forthe definition of spectral similari
18、ty). Intensities of peakmaxima of suitable emission spectra are then used to developcalibration curves for quantification.NOTE 1Although some sections of the characterization part of this testmethod are similar to Test Method D3650, there are also significantdifferences (see Annex A1). Since the pur
19、pose and intent of the two testmethods are different, one should not be substituted for the other.5. Significance and Use5.1 This test method is useful for characterization and rapidquantification of PAH mixtures including petroleum oils, fuels,creosotes, and industrial organic mixtures, either wate
20、rborne orobtained from tanks.5.2 The unknown PAH mixture is first characterized by itsfluorescence emission and synchronous scanning spectra. Thena suitable site-specific calibration standard with similar spectralcharacteristics is selected as described in Annex A1. Thiscalibration standard may also
21、 be well-characterized by otherindependent methods such as gas chromatography (GC), GC-mass spectrometry (GC-MS), or high performance liquidchromatography (HPLC). Some suggested independent ana-lytical methods are included in References (1-7)4and TestMethod D4657. Other analytical methods can be sub
22、stituted byan experienced analyst depending on the intended data qualityobjectives. Peak maxima intensities of appropriate fluores-cence emission spectra are then used to set up suitablecalibration curves as a function of concentration. Furtherdiscussion of fluorescence techniques as applied to the
23、char-acterization and quantification of PAHs and petroleum oils canbe found in References (8-18).5.3 For the purpose of the present test method polynucleararomatic hydrocarbons are defined to include substituted poly-cyclic aromatic hydrocarbons with functional groups such ascarboxyl acid, hydroxy,
24、carbonyl and amino groups, andheterocycles giving similar fluorescence responses to PAHs ofsimilar molecular weight ranges. If PAHs in the more classicdefinition, that is, unsubstituted PAHs, are desired, chemicalreactions, extractions, or chromatographic procedures may berequired to eliminate these
25、 other components. Fortunately, forthe most commonly expected PAH mixtures, such substitutedPAHs and heterocycles are not major components of themixtures and do not cause serious errors.6. Interferences6.1 The fluorescence spectra may be distorted or quantifi-cation may be affected if the sample is
26、contaminated with anappreciable amount of other fluorescent chemicals that areexcited and which fluoresce in the same spectral regions withrelatively high fluorescence yields. Usually the fluorescencespectra would be distorted at levels greater than 1 to 2 % ofsuch impurities before the quantificati
27、on would be seriouslyaffected. (WarningStorage of samples in improper contain-ers (for example, plastics other than TFE-fluorocarbon) mayresult in contamination.)NOTE 2Spectroquality solvents may not have low enough fluores-cence background to be used as solvent blanks. Solvent lots vary in theconte
28、nt of fluorescent impurities that may increase with storage time evenfor unopened bottles.NOTE 3This test method is normally used without a matrix spike dueto possible fluorescence interference by the spike. If a spike is to be used,it must fluoresce in a spectral region where it will not interfere
29、with thequantification process. Compounds that could be used are dyes thatfluoresce at longer wavelengths than the emission of the PAH mixture.6.2 If the PAH mixture to be analyzed is a complex mixturesuch as an oil or creosote, it is assumed that a well-characterized sample of the same or similar m
30、aterial is avail-able as a calibration standard so the fluorescent fraction of themixture can be ratioed against the total mixture. Otherwise,since the samples and standards are weighed, the nonfluores-cent portion of the mixture would bias the quantificationalthough the characterization portion of
31、the test method forPAHs given in Annex A1 would be unaffected.7. Apparatus7.1 Fluorescence SpectrometerAn instrument recordingin the spectral range of 250 nm to at least 600 nm for bothexcitation and emission responses and capable of scanningboth monochromators simultaneously at a constant speed wit
32、ha constant wavelength offset between them for synchronousscanning. The instrument should meet the specifications inTable 1. (Also known as spectrofluorometer or fluorescencespectrophotometer.) Consult manufacturers instrument manu-als for specific operating instructions.NOTE 4Although the character
33、ization section of this test method4The boldface numbers in parentheses refer to a list of references at the end ofthis standard.TABLE 1 Specifications for Fluorescence SpectrometersWavelength ReproducibilityExcitation monochromator 2 nm or betterEmission monochromator 2 nm or betterGratings (Typica
34、l Values)Excitation monochromator minimum of 600 lines/mm blazed at300 nmEmission monochromator minimum of 600 lines/mm blazed at300 nm or 500 nmPhotomultiplier TubeS-20 or S-5 response or equivalentSpectral ResolutionsExcitation monochromator spectral bandpass of 2.5 nm or lessEmission monochromato
35、r spectral bandpass 2.5 nm or lessMaximum bandpasses for both monochromators at least 10 nmD5412 93 (2017)12(given in Annex A1) is similar to Test Method D3650 in many respects,there are differences in the purpose and intents of the two test methods.The purpose of the characterization step of this t
36、est method is to find anoil with similar fluorescence properties as the sample in order to serve asan appropriate calibration standard for quantification. Other differencesbetween the test methods are instrumentation requirements and the use ofsynchronous spectra as well as emission spectra for this
37、 test method.7.2 Excitation SourceA high-pressure xenon lamp (a150-W continuous xenon lamp or a 10-W pulsed xenon lamphas been proven acceptable). Other continuum sources (eithercontinuous or pulsed) having sufficient intensity throughout theultraviolet and visible regions may also be used.7.3 Fluor
38、escence CellsStandard cells made fromfluorescence-free fused silica with a path length of 10 mm anda height of at least 45 mm. Stoppered cells may be preferred toprevent sample evaporation and contamination.7.4 Data Recording SystemPreferably the instrumentshould be interfaced to a suitable computer
39、 system compatiblewith the instrument and with suitable software for spectral datamanipulation. Use of a strip chart or X-Y recorder with aresponse time of less than 1 s for full-scale deflection isacceptable.7.5 Micropipet, glass, 10 to 50-L capacity.7.6 Weighing Pans, 5 to 7-mm diameter, 18-mm thi
40、ck, madeof aluminum or equivalent. Check pans for contamination.8. Reagents and Materials8.1 Purity of ReagentsUse spectroquality grade reagentsin all instances unless otherwise stated. Since the goal is tohave as low a fluorescence blank as possible, and sincedifferent brands and lots of spectroqua
41、lity solvent may vary,check reagents frequently.8.2 Purity of WaterReferences to water mean Type IVwater conforming to Specification D1193. Since fluorescentorganic impurities in the water may introduce an interference,check the purity of the water by analyzing a water blank usingthe same instrument
42、al conditions as for the solvent blank.8.3 Acetone, spectroquality, (CH3COCH3).8.4 Cyclohexane, spectroquality or HPLC grade. The fluo-rescence solvent blank must be as low as possible and less than5 % of the intensity of the maximum emission peak for thelowest concentration of PAHs analyzed. Dispen
43、se cyclohexaneduring the procedure from either a TFE-fluorocarbon or glasswash bottle, but, for prolonged storage, store cyclohexane onlyin glass.8.5 Nitric Acid (1+1)Carefully add one volume of con-centrated HNO3(sp gr 1.42) to one volume of water8.6 TFE-Fluorocarbon Strips, 25 mm by 75 mm, 0.25-mm
44、thickness. Use TFE strips when sampling neat PAH films onwater as described in Practices D4489.9. Sampling and Sample Preparation9.1 Collect a representative sample (see Practices D4489 forwater samples).9.2 Preserve samples in containers as specified in PracticeD3325. Do not cool samples below 5C t
45、o avoid dewaxing ofoil or creosote samples.9.3 Neat PAH samples (including surface films or layers onwater) require only dilution in spectroquality cyclohexane.Prepare initial concentration for the unknown at 100 g/mL fora check of the fluorescence signal. Further dilutions down to 1/mL may be neede
46、d to bring the fluorescence signal into thelinear range and to avoid self-absorption effects in the solution.Most PAH mixtures and oils have been found to be soluble incyclohexane at the concentrations listed. Alternative solventscan be substituted with appropriate tests.9.4 If any unknown PAH mixtu
47、re is dissolved in water, testthe mixture with appropriate dilutions or preconcentrations asrequired. The assumption is that no naturally-occurring fluo-rescent materials such as humic or fulvic acids are present atlevels interfering with the determination (refer to Fig.A2.5 andFig. A2.6 to show tha
48、t humic acid does not interfere with thetest method even at high (g/L) levels). This usually becomesa problem only at PAH levels in the low g/L range. Extractionmethods (or separation by column chromatography) are listedin Practice D3326.9.4.1 An extraction method that proved satisfactory for thecol
49、laborative test is as follows:9.4.1.1 Pour 50.0 mL of the sample into a separatory funnel,add 5.0 mL of cyclohexane and shake for 2 min. Vent theseparatory funnel occasionally. Withdraw the aqueous layer(keep this for a second extraction). Collect the cyclohexaneextract in a 10-mL volumetric flask. Add 5.0 mL of cyclo-hexane to the aqueous layer and perform a second extraction.Combine the two extracts and dilute to 10.0 mL with cyclo-hexane.9.4.1.2 For field use, it has proven satisfactory to use areagent bottle instead of a separatory funnel. Pour 50.0 mL
