1、Designation: D4294 10D4294 16Standard Test Method forSulfur in Petroleum and Petroleum Products by EnergyDispersive X-ray Fluorescence Spectrometry1This standard is issued under the fixed designation D4294; the number immediately following the designation indicates the year oforiginal adoption or, i
2、n 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.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope
3、*1.1 This test method covers the determination of total sulfur in petroleum and petroleum products that are single-phase andeither liquid at ambient conditions, liquefiable with moderate heat, or soluble in hydrocarbon solvents. These materials can includediesel fuel, jet fuel, kerosine, other disti
4、llate oil, naphtha, residual oil, lubricating base oil, hydraulic oil, crude oil, unleadedgasoline, gasohol, gasoline-ethanol blends, biodiesel (see Note 2), and similar petroleum products.NOTE 1Oxygenated fuels with ethanol or methanol contents exceeding the limits given in Table 1 can be dealt wit
5、h using this test method, but theprecision and bias statements do not apply (see Appendix X3).NOTE 2For samples with high oxygen contents (3 wt %) weight %) sample dilution as described in 1.3 or matrix matching must be performed toassure accurate results.1.2 Interlaboratory studies on precision rev
6、ealed the scope to be 1717 mg mg/kg kg to 4.6 mass %. An estimate of this testmethods pooled limit of quantitation (PLOQ) is 16.016.0 mg mg/kg kg as calculated by the procedures in Practice D6259.However, because instrumentation covered by this test method can vary in sensitivity, the applicability
7、of the test method at sulfurconcentrations below approximately 20 mg/kg must be determined on an individual basis. An estimate of the limit of detection isthree times the reproducibility standard deviation, and an estimate of the limit of quantitation2 is ten times the reproducibilitystandard deviat
8、ion.1.3 Samples containing more than 4.6 mass % sulfur can be diluted to bring the sulfur concentration of the diluted materialwithin the scope of this test method. Samples that are diluted can have higher errors than indicated in Section 16 than non-dilutedsamples.1.4 Volatile samples (such as high
9、 vapor pressure gasolines or light hydrocarbons) may not meet the stated precision becauseof selective loss of light materials during the analysis.1 This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
10、 SubcommitteeD02.03 on Elemental Analysis.Current edition approved Feb. 15, 2010Jan. 1, 2016. Published March 2010February 2016. Originally approved in 1983. Last previous edition approved in 20082010 asD4294D4294 10.08a1. DOI: 10.1520/D4294-10.10.1520/D4294-16.2 Analytical Chemistry, Vol 55, 1983,
11、pp. 2210-2218.TABLE 1 Concentrations of Interfering SpeciesAElement Mass % ToleratedPhosphorus 0.3Zinc 0.6Barium 0.8Lead 0.9Calcium 1Chlorine 3Ethanol (Note 11) 8.6Methanol (Note 11) 6Fatty Acid Methyl Ester (FAME) 5A The concentrations of substances in this table were determined by the calcula-tion
12、 of the sum of the mass absorption coefficients times mass fraction of eachelementpresent.Thiscalculationwasmadefordilutionsofrepresentativesamplescontaining approximately 3 % of interfering substances and 0.5 % sulfur.This document is not an ASTM standard and is intended only to provide the user of
13、 an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as pub
14、lished by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States11.5 A fundamental assumption in this test method is that the sta
15、ndard and sample matrices are well matched, or that the matrixdifferences are accounted for (see 5.2). Matrix mismatch can be caused by C/H ratio differences between samples and standards(see Section 5) or by the presence of other heteroatoms.1.6 The values stated in SI units are to be regarded as s
16、tandard. No other units of measurement are included in this standard.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the
17、applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsD4177 Practice for Automatic Sampling of Petroleum and Petroleum ProductsD6259 Practice for Determination of a Pooled Limit of Quantita
18、tion for a Test MethodD6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-ment System PerformanceD7343 Practice for Optimization, Sample Handling, Calibration, and Validation of X-ray Fluorescence Spectrometry Methodsfor Elemental
19、Analysis of Petroleum Products and LubricantsE29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications3. Summary of Test Method3.1 The sample is placed in the beam emitted from an X-ray tube. The resultant excited characteristic X radiation is measured,and t
20、he accumulated count is compared with counts from previously prepared calibration samples to obtain the sulfur concentrationin mass % and/or mg/kg. mass percent or mg/kg, or both. A minimum of three groups of calibration samples are required to spanthe concentration range: 0.0 0.0 mass % to 0.1 mass
21、 %, 0.1 0.1 mass % to 1.0 mass %, and 1.0 1.0 mass % to 5.0 mass % sulfur.(See Practice D7343.)4. Significance and Use4.1 This test method provides rapid and precise measurement of total sulfur in petroleum and petroleum products with aminimum of sample preparation. A typical analysis time is 11 min
22、 to 5 min 5 min per sample.4.2 The quality of many petroleum products is related to the amount of sulfur present. Knowledge of sulfur concentration isnecessary for processing purposes. There are also regulations promulgated in federal, state, and local agencies that restrict theamount of sulfur pres
23、ent in some fuels.4.3 This test method provides a means of determining whether the sulfur content of petroleum or a petroleum product meetsspecification or regulatory limits.4.4 When this test method is applied to petroleum materials with matrices significantly different from the calibration materia
24、lsspecified in 9.1, the cautions and recommendations in Section 5 should be observed when interpreting results.5. Interferences5.1 Spectral interferences are caused by the closeness of the X-ray characteristic lines of the elements present in a sample andthe limited detector ability to completely re
25、solve them. As a result, the lines produce spectral peaks that overlap with each other.Spectral interferences may arise from samples containing lead alkyls, silicon, phosphorus, calcium, potassium, halides, and catalystparticles if present at concentrations greater than one tenth of the measured con
26、centration of sulfur, or more than a few hundredmilligrams/kilogram (parts per millionmass ppm). Follow the manufacturers operating-guide to compensate for theinterferences.5.2 Matrix effects are caused by concentration variations of the elements in a sample. These variations directly influence X-ra
27、yabsorption and change the measured intensity of each element. For example, performance enhancing additives, such as oxygenatesin gasoline, may affect the apparent sulfur reading. Other matrix related interferences may arise from heavy metal additives, leadalkyls, and elements such as silicon, phosp
28、horus, calcium, potassium, and the halides, especially if present at concentrations greaterthan one tenth of the measured concentration of sulfur, or more than a few hundred milligrams/kilogram (parts per millionppm).These types of interferences are always present in X-ray fluorescence analysis and
29、are completely unrelated to spectralinterferences.5.3 The interferences mentioned in 5.1 and 5.2 may be compensated for in contemporary instruments with the use of built-insoftware for spectra deconvolution or overlap correction and inter-element correction by multiple regression or by othermathemat
30、ical methods.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.D4294 1625.4 In general, petroleum materials wit
31、h compositions that vary from oils as specified in 9.1 may be analyzed with standardsmade from base materials that are of the same, or similar, composition. Thus, a gasoline may be simulated by mixing isooctaneand toluene in a ratio that approximates the true aromatic content of the samples to be an
32、alyzed. Standards made from thissimulated gasoline will produce results that are more accurate than results obtained using white oils. Suggestions are given in Table2.NOTE 3In the case of petroleum materials that contain suspended water, it is recommended that the water be removed before testing or
33、that the samplebe thoroughly homogenized and immediately tested. The interference is greatest if the water creates a layer over the transparent film as it will attenuatethe X-ray intensity for sulfur. One such method to accomplish the removal of water is to centrifuge the sample first under ambient
34、sealed conditions, takingcare that the sample integrity is not compromised.6. Apparatus6.1 Energy-dispersive X-ray Fluorescence AnalyzerEnergy dispersive X-ray fluorescence analyzer may be used if its designincorporates, as a minimum, the following features and if test results from it are shown to b
35、e equivalent on the samples of interest.Required design features include:6.1.1 Source of X-ray Excitation , X-ray tube with excitation energy above 2.5 keV.6.1.2 Removable Sample Cup, equipped with replaceable X-ray transparent plastic film windows and providing a sample depthof at least 4 mm and a
36、diameter of at least 10 mm.6.1.3 X-ray Detector, with high sensitivity and a resolution value (Full Width at Half Maximum, FWHM) not to exceed 800 eVat 2.3 keV.6.1.4 Filters or other means of discriminating between sulfur K radiation and other X-rays of higher energy.6.1.5 Signal conditioning and da
37、ta handling electronics that include the functions of X-ray intensity counting, a minimum oftwo energy regions, spectral overlap corrections, and conversion of sulfur X-ray intensity into mass percent sulfur concentration.6.1.6 The analyzer shall have the sensitivity under optimized measurement cond
38、itions to measure the concentration of sulfurat the 0.05 % level with a demonstrated error due to counting statistics with one standard deviation not greater than 0.5 percent%relative at the 500500 mg mg/kg kg level. This requirement pertains to sample measurements of less than 1000 mg/kg.6.1.7 Disp
39、lay or Printer that reads out in mass %mass percent sulfur and/or mg/kg sulfur.or mg/kg sulfur, or both.6.2 Analytical Balance, with an accuracy and resolution of 0.1 mg 0.1 mg and capable of weighing up to 100 g.100 g.NOTE 4Operation of analyzers using X-ray tube sources is to be conducted in accor
40、dance with the manufacturers safety instructions.7. Reagents7.1 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 Chemical Society (AC
41、S) wheresuch specifications are available.4 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently highpurity to permit its use without lessening the accuracy of the determination.7.2 Di-n-Butyl Sulfide (DBS), a high-purity standard with a certified analysis f
42、or sulfur content. Use the certified sulfur contentand the material purity when calculating the exact concentrations of the calibration standards (see 9.1). (WarningDi-n-butylsulfide is flammable and toxic.)NOTE 5It is essential to know the concentration of sulfur in the di-n-butyl sulfide, not only
43、 the purity, since impurities may also be sulfur containingcompounds.7.3 Drift Correction Monitor(s) (Optional)Several different materials have been found to be suitable for use as drift correctionmonitors. Appropriate drift monitor samples should be permanent materials that are stable with respect
44、to repeated exposure toX-rays. Stable liquids like polysulfide oils, glass, or metallic specimens are recommended. Liquids, pressed powders, and solid4 Reagent Chemicals, American Chemical Society Specifications , American Chemical Society, Washington, DC. For suggestions on the testing of reagents
45、not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.TABLE 2 Matrix DiluentsMatrix Matrix Diluent Alternate Diluent
46、#2 Diesel #2 Diesel KerosineNaphtha Kerosine Kerosine Kerosine #2 DieselResiduals Lube Oil MOWHALubricating Base Oils Lube Oil MOWLBHydraulic Oils Lube Oil MOWLBCrude Oil Lube Oil MOWHAJet Fuels Kerosine Gasoline Gasoline A MOWH = mineral oil white heavyB MOWL = mineral oil white lightD4294 163mater
47、ials that degrade with repeated exposure to X-rays should not be used. Examples of sulfur containing materials that have beenfound to be suitable include a renewable liquid petroleum material, a metal alloy, or a fused glass disk. The monitors countingrate, in combination with count time, shall be s
48、ufficient to give a relative counting error of less than 1 %. The counting rate forthe monitor sample is determined during calibration (see 9.2.1) and again at the time of analysis (see 12.2). These counting ratesare used to calculate a drift correction factor (see 15.6).7.3.1 Drift correction is us
49、ually implemented automatically in software, although the calculation can readily be done manually.For X-ray instruments that are highly stable, the magnitude of the drift correction factor may not differ significantly from unity.7.4 Polysulfide Oil, generally nonyl polysulfides containing a known percentage of sulfur diluted in a hydrocarbon matrix.(WarningMay cause allergic skin reactions.)NOTE 6Polysulfide oils are high molecular weight oils that contain high concentrations of sulfur, as high as 50 weight percent.%. They exhibitexcellent physical pro
