1、Designation: D7039 15D7039 15aStandard Test Method forSulfur in Gasoline, Diesel Fuel, Jet Fuel, Kerosine,Biodiesel, Biodiesel Blends, and Gasoline-Ethanol Blendsby Monochromatic Wavelength Dispersive X-rayFluorescence Spectrometry1This standard is issued under the fixed designation D7039; the numbe
2、r immediately 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. Scope*1
3、.1 This test method covers the determination of total sulfur by monochromatic wavelength-dispersive X-ray fluorescence(MWDXRF) spectrometry in single-phase gasoline, diesel fuel, refinery process streams used to blend gasoline and diesel, jet fuel,kerosine, biodiesel, biodiesel blends, and gasoline-
4、ethanol blends.NOTE 1Volatile samples such as high-vapor-pressure gasolines or light hydrocarbons might not meet the stated precision because of the evaporationof light components during the analysis.1.2 The range of this test method is between the pooled limit of quantitation (PLOQ) value (calculat
5、ed by procedures consistentwith Practice D6259) of 3.2 mgkg total sulfur and the highest level sample in the round robin, 2822 mgkg total sulfur.1.3 Samples containing oxygenates can be analyzed with this test method provided the matrix of the calibration standards iseither matched to the sample mat
6、rices or the matrix correction described in Section 5 or Annex A1 is applied to the results. Theconditions for matrix matching and matrix correction are provided in the Interferences section (Section 5).1.4 Samples with sulfur content above 2822 mgkg can be analyzed after dilution with appropriate s
7、olvent (see 5.4). Theprecision and bias of sulfur determinations on diluted samples has not been determined and may not be the same as shown for neatsamples (Section 15).1.5 When the elemental composition of the samples differ significantly from the calibration standards used to prepare thecalibrati
8、on curve, the cautions and recommendation in Section 5 should be carefully observed.1.6 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.7 This standard does not purport to address all of the safety concerns, if any, associa
9、ted with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. For specific hazard information, see 3.1.2. Referenced Documents2.1 ASTM Standards:2D4057 Practice for Ma
10、nual Sampling of Petroleum and Petroleum ProductsD4177 Practice for Automatic Sampling of Petroleum and Petroleum ProductsD6259 Practice for Determination of a Pooled Limit of QuantitationD6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical
11、 Measure-ment System PerformanceD6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and LubricantsD7343 Practice for Optimization, Sample Handling, Calibration, and Validation of X-ray Fluorescence Spectrometry Methodsfor Elemental Analysis of P
12、etroleum Products and Lubricants1 This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved April 1, 2015July 1, 2015. Published May 2015Aug
13、ust 2015. Originally approved in 2004. Last previous edition approved in 20132015 asD7039 13.D7039 15. DOI: 10.1520/D7039-15.10.1520/D7039-15A.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvol
14、ume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adeq
15、uately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM
16、International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12.2 EPA Documents:340 CFR 80.584 Code of Federal Regulations; Title 40; Part 80; U.S. Environmental Agency, July 1, 20053. Summary of Test Method3.1 A monochromatic X-ray beam with a wavelength suitabl
17、e to excite the K-shell electrons of sulfur is focused onto a testspecimen contained in a sample cell (see Fig. 1). The fluorescent K radiation at 0.5373 nm (5.373 ) emitted by sulfur is collectedby a fixed monochromator (analyzer). The intensity (counts per second) of the sulfur X rays is measured
18、using a suitable detectorand converted to the concentration of sulfur (mg/kg) in a test specimen using a calibration equation. Excitation by monochromaticX rays reduces background, simplifies matrix correction, and increases the signal/background ratio compared to polychromaticexcitation used in con
19、ventional WDXRF techniques.4 (WarningExposure to excessive quantities of X-ray radiation is injuriousto health. The operator needs to take appropriate actions to avoid exposing any part of his/her body, not only to primary X rays,but also to secondary or scattered radiation that might be present. Th
20、e X-ray spectrometer should be operated in accordance withthe regulations governing the use of ionizing radiation.)4. Significance and Use4.1 This test method provides for the precise measurement of the total sulfur content of samples within the scope of this testmethod with minimal sample preparati
21、on and analyst involvement. The typical time for each analysis is five minutes.4.2 Knowledge of the sulfur content of diesel fuels, gasolines, and refinery process streams used to blend gasolines is importantfor process control as well as the prediction and control of operational problems such as un
22、it corrosion and catalyst poisoning, andin the blending of products to commodity specifications.4.3 Various federal, state, and local agencies regulate the sulfur content of some petroleum products, including gasoline anddiesel fuel. Unbiased and precise determination of sulfur in these products is
23、critical to compliance with regulatory standards.5. Interferences5.1 Differences between the elemental composition of test samples and the calibration standards can result in biased sulfurdeterminations. For samples within the scope of this test method, elements contributing to bias resulting from d
24、ifferences in thematrices of calibrants and test samples are hydrogen, carbon, and oxygen. A matrix-correction factor (C) can be used to correctthis bias; the calculation is described in AnnexA1. For general analytical purposes, the matrices of test samples and the calibrantsare considered to be mat
25、ched when the calculated correction factor C is within 0.98 to 1.04. No matrix correction is required withinthis range. A matrix correction is required when the value of C is outside the range of 0.98 to 1.04. For most testing, matrixcorrection can be avoided with a proper choice of calibrants. For
26、example, based on the example graph in Annex A1 (Fig. 2), acalibrant with 86 mass % carbon and 14 mass % hydrogen can cover non-oxygen containing samples with C/H ratios from 5.4to 8.5. For gasolines with oxygenates, up to 2.3 mass % oxygen (12 mass % MTBE) can be tolerated for test samples with the
27、same C/H ratio as the calibrants.5.2 Fuels containing large quantities of oxygenates, such as biodiesel, biodiesel blends, and gasoline-ethanol blends, can havea high oxygen content leading to significant absorption of sulfur K radiation and low sulfur results.3 Available from U.S. Government Printi
28、ng Office, 732 N. Capitol Street, NW, Washington, DC 20401.4 Bertin, E. P., Principles and Practices of X-ray Spectrometric Analysis , Plenum Press, New York, 1975, pp. 115118.FIG. 1 Schematic of the MWDXRF AnalyzerD7039 15a25.2.1 Biodiesel and biodiesel blends may be analyzed using this test method
29、 by applying correction factors to the results or usingcalibration standards that are matrix-matched to the test sample (see Table 1). Correction factors may be calculated (see AnnexA1), or obtained from Table 2 if the sample has been measured on a mineral oil calibration curve.5.2.2 Gasoline-ethano
30、l blends may be analyzed using this test method by applying correction factors to the results or usingcalibration standards that are matrix matched to the test sample (see Table 1). Correction factors may be calculated (see AnnexA1), or obtained from the correction tables. Use Table 3 if the sample
31、has been measured on a mineral oil calibration curve, oruse Table 4 if the sample has been measured on an ethanol calibration curve. Ethanol-based calibrants can be used forgasoline-ethanol blends. Ethanol-based calibrants are recommended for gasoline-ethanol blends containing more than 50 % (byvolu
32、me) ethanol.5.3 Other samples having interferences as described in 5.1 may be analyzed using this test method by applying correctionfactors to the results or by using calibration standards that are matrix matched to the test sample (see Table 1). Correction factorsmay be calculated as described in A
33、nnex A1.5.4 To minimize any bias in the results, use calibration standards prepared from sulfur-free base materials of the same or similarelemental composition as the test samples. When diluting samples, use a diluent with an elemental composition the same or similarto the base material used for pre
34、paring the calibration standards.5.4.1 Abase material for gasoline can be approximately simulated by mixing 2,2,4-trimethylpentane (isooctane) and toluene ina ratio that approximates the expected aromatic content of the samples to be analyzed.6. Apparatus6.1 Monochromatic Wavelength Dispersive X-ray
35、 Fluorescence (MWDXRF) Spectrometer5,equipped for X-ray detection at0.5373 nm (5.373). Any spectrometer of this type can be used if it includes the following features, and the precision and biasof test results are in accordance with the values described in Section 15.6.1.1 X-ray Source, capable of p
36、roducing X rays to excite sulfur. X-ray tubes with a power 25W capable of producing Rh L,Pd L, Ag L, Ti K, Sc K, and Cr K radiation are recommended for this purpose.6.1.2 Incident-beam Monochromator, capable of focusing and selecting a single wavelength of characteristic X rays from thesource onto t
37、he specimen.5 The sole source of this apparatus known to the committee at this time is X-ray Optical Systems, Inc., 15 Tech Valley Drive, East Greenbush, NY 12061. If you are awareof alternative suppliers, please provide this information toASTM International Headquarters.Your comments will receive c
38、areful consideration at a meeting of the responsibletechnical committee, which you may attend.FIG. 2 Matrix Correction for a Test Sample vs. C/H and Total Oxygen Content Using Chromium K for the Excitation BeamD7039 15a36.1.3 Optical Path, designed to minimize the absorption along the path of the ex
39、citation and fluorescent beams using a vacuumor a helium atmosphere. A vacuum of 2.7 kPa (20 Torr) is recommended. The calibration and test measurements must be donewith identical optical paths, including vacuum or helium pressure.6.1.4 Fixed-channel Monochromator, suitable for dispersing sulfur K X
40、 rays.6.1.5 Detector, designed for efficient detection of sulfur K X rays.6.1.6 Single-Channel Analyzer, an energy discriminator to monitor only sulfur radiation.6.1.7 Removable Sample Cell, an open-ended specimen holder compatible with the geometry of the MWDXRF spectrometerand designed to use repl
41、aceable X-ray transparent film (see 6.1.8) to hold a liquid specimen with a minimum depth of 5 mm. Thesample cell must not leak when fitted with X-ray transparent film. A disposable cell is recommended.6.1.8 X-Ray Transparent Film, for containing and supporting the test specimen in the sample cell (
42、see 6.1.7) while providinga low-absorption window for X rays to pass to and from the sample. Any film resistant to chemical attack by the sample, free ofsulfur, and X-ray transparent can be used, for example, polyester, polypropylene, polycarbonate, and polyimide. However, samplesof high aromatic co
43、ntent can dissolve polyester and polycarbonate films.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents conform to the specifications of the Committee on Analytical Reagents of the American Ch
44、emical Society where suchspecifications are available.6 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purityto permit its use without lessening the accuracy of the determination.7.2 Calibration-Check Samples, for verifying the accuracy of a calib
45、ration. The check samples shall have known sulfur contentand not be used in determining the calibration curve. A standard from the same reliable and consistent source of calibrationstandards used to determine the calibration curve is convenient to check the calibration.7.3 Di-n-butyl Sulfide, a high
46、-purity liquid with a certified sulfur concentration. Use the certified sulfur concentration whencalculating the exact concentrations of sulfur in calibration standards. (WarningDi-n-butyl sulfide is flammable and toxic.Prepared solutions may not be stable several months after preparation.)NOTE 2It
47、is essential to know the concentration of sulfur in the di-n-butyl sulfide, not only the purity, since impurities can also be sulfur-containingcompounds. The sulfur content may be determined via mass dilution in sulfur-free white oil followed by a direct comparison analysis against NIST (orother pri
48、mary standards body) reference materials.7.4 Drift-Monitor Sample (Optional), to determine and correct instrument drift over time (see 10.4, 11.1, and 12.1). Variousforms of stable sulfur-containing materials are suitable drift-correction samples, for example, liquid petroleum, solid, pressedpowder,
49、 metal alloy, and fused glass. The count rate displayed by the monitor sample, in combination with a convenient count time(T), shall be sufficient to give a relative standard deviation (RSD) of 1 % (see Appendix X1).NOTE 3Calibration standards may be used as drift-monitor samples. Because it is desirable to discard test specimens after each determination, a lowercost material is suggested for daily use. Any stable material can be used for daily monitoring of drift.NOTE 4The effect of drift correction on the precision and bias of this test method has not
