ASTM D2622-2008 Standard Test Method for Sulfur in Petroleum Products by Wavelength Dispersive X-ray Fluorescence Spectrometry.pdf

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1、Designation: D 2622 08An American National StandardStandard Test Method forSulfur in Petroleum Products by Wavelength DispersiveX-ray Fluorescence Spectrometry1This standard is issued under the fixed designation D 2622; the number immediately following the designation indicates the year oforiginal a

2、doption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense

3、.1. Scope*1.1 This test method covers the determination of total sulfurin petroleum and petroleum products that are single-phase andeither liquid at ambient conditions, liquefiable with moderateheat, or soluble in hydrocarbon solvents. These materials caninclude diesel fuel, jet fuel, kerosene, othe

4、r distillate oil,naphtha, residual oil, lubricating base oil, hydraulic oil, crudeoil, unleaded gasoline, gasohol and biodiesel.1.2 The range of this test method is between the PLOQvalue (calculated by procedures consistent with PracticeD 6259) of 3 mg/kg total sulfur and the highest level sample in

5、the round robin, 4.6 wt. % total sulfur.NOTE 1Instrumentation covered by this test method can vary insensitivity. The applicability of the test method at sulfur concentrationsbelow 3 mg/kg may be determined on an individual basis for WDXRFinstruments capable of measuring lower levels, but precision

6、in this testmethod does not apply.1.2.1 The values of the limit of quantitation (LOQ) andmethod precision for a specific laboratorys instrument dependson instrument source power (low or high power), sample type,and the practices established by the laboratory to perform themethod.1.3 Samples containi

7、ng more than 4.6 mass % sulfur shouldbe diluted to bring the sulfur concentration of the dilutedmaterial within the scope of this test method. Samples that arediluted can have higher errors than indicated in Section 14 thannon-diluted samples.1.4 Volatile samples (such as high vapor pressure gasolin

8、esor light hydrocarbons) may not meet the stated precisionbecause of selective loss of light materials during the analysis.1.5 A fundamental assumption in this test method is that thestandard and sample matrices are well matched, or that thematrix differences are accounted for (see 12.2). Matrix mis

9、-match can be caused by C/H ratio differences between samplesand standards or by the presence of other interfering heteroa-toms or species (see Table 1).1.6 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.7 This standard does

10、 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Stand

11、ards:2D 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD 4294 Test Method for Sulfur in Petroleum and PetroleumProducts by Energy-Dispersive X-ray Fluorescence Spec-trometryD 4927 Test Methods for Elemental

12、 Analysis of Lubricantand Additive ComponentsBarium, Calcium, Phospho-rus, Sulfur, and Zinc by Wavelength-Dispersive X-RayFluorescence SpectroscopyD 6259 Practice for Determination of a Pooled Limit ofQuantitationD 6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniqu

13、es to Evaluate AnalyticalMeasurement System PerformanceD 7343 Practice for Optimization, Sample Handling, Cali-bration, and Validation of X-ray Fluorescence Spectrom-etry Methods for Elemental Analysis of Petroleum Prod-ucts and LubricantsE29 Practice for Using Significant Digits in Test Data toDete

14、rmine Conformance with Specifications3. Summary of Test Method3.1 The sample is placed in the X-ray beam, and the peakintensity of the sulfur Ka line at 0.5373 nm is measured. The1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct r

15、esponsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved March 1, 2008. Published March 2008. Originallyapproved in 1967. Last previous edition approved in 2007 as D 262207.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service

16、 at serviceastm.org. For Annual Book of ASTMStandards volume information, 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 19428-2

17、959, United States.background intensity, measured at a recommended wavelengthof 0.5190 nm (0.5437 nm for a Rh target tube) is subtractedfrom the peak intensity. The resultant net counting rate is thencompared to a previously prepared calibration curve or equa-tion to obtain the concentration of sulf

18、ur in mg/kg or mass %(see Section 12).4. Significance and Use4.1 This test method provides rapid and precise measure-ment of total sulfur in petroleum and petroleum products witha minimum of sample preparation. A typical analysis time is 1to 2 minutes per sample.4.2 The quality of many petroleum pro

19、ducts is related to theamount of sulfur present. Knowledge of sulfur concentration isnecessary for processing purposes. There are also regulationspromulgated in federal, state, and local agencies that restrictthe amount of sulfur present in some fuels.4.3 This test method provides a means of determi

20、ningwhether the sulfur content of petroleum or a petroleum productmeets specification or regulatory limits.4.4 When this test method is applied to petroleum materialswith matrices significantly different from the white oil calibra-tion materials specified in this test method, the cautions andrecomme

21、ndations in Section 5 should be observed wheninterpreting results.NOTE 2The equipment specified for Test Method D 2622 tends to bemore expensive than that required for alternative test methods, such asTest Method D 4294. Consult the Index toASTM Standards for alternativetest methods.5. Interferences

22、5.1 When the elemental composition (excluding sulfur) ofsamples differs significantly from the standards, errors in thesulfur determination can result. For example, differences in thecarbon-hydrogen ratio of sample and calibration standardsintroduce errors in the determination. Some other interferen

23、cesand action levels are listed in Table 1. If a sample is knownfrom its history or another analysis to contain any of thespecies listed in Table 1 at or above the values listed there, thatsample should be diluted with blank sulfur solvent to reducethe interferent concentration below the value to mi

24、tigate theeffect of this interference.NOTE 3The concentrations of the first seven substances in Table 1were determined by the calculation of the sum of the mass absorptioncoefficients times mass fraction of each element present. This calculationwas made for dilutions of representative samples contai

25、ning approxi-mately 3 % of interfering substances and 0.5 % sulfur. Refer to Note 16for additional information regarding FAME, ethanol, and methanol.5.2 Fuels containing large quantities of FAME, ethanol, ormethanol (see Table 1) have a high oxygen content leading tosignificant absorption of sulfur

26、Ka radiation and low sulfurresults. Such fuels can, however, be analyzed using this testmethod provided either that correction factors are applied tothe results (when calibrating with white oils) or that thecalibration standards are prepared to match the matrix of thesample. See 11.5.5.3 In general,

27、 petroleum materials with compositions thatvary from white oils as specified in 9.1 can be analyzed withstandards made from base materials that are of the same orsimilar composition. Thus a gasoline may be simulated bymixing isooctane and toluene in a ratio that approximates theexpected aromatic con

28、tent of the samples to be analyzed.Standards made from this simulated gasoline can produceresults that are more accurate than results obtained using whiteoil standards.5.4 Test Method D 4927 is the recommended test methodfor the determination of sulfur 100 mg/kg in lubricating oilsand lubricating oi

29、l additives because method D 4927 imple-ments inter-element correction factors. Method D 2622 is notsuitable because it does not encompass the measurement of theadditional elements present in lubricating oils and their addi-tives making matrix correction impossible.6. Apparatus6.1 Wavelength Dispers

30、ive X-Ray Fluorescence Spectrom-eter (WDXRF), equipped for X-ray detection in the wavelengthrange from about 0.52 nm to about 0.55 nm (specifically at0.537 nm). For optimum sensitivity to sulfur, the instrumentshould be equipped with the following items:6.1.1 Optical Path, vendor specified, helium p

31、referred, am-bient air or nitrogen are inferior.6.1.2 Pulse-Height Analyzer, or other means of energydiscrimination.6.1.3 Detector, for the detection of X-rays with wavelengthsin the range of interest (from about 0.52 nm to about 0.55 nm).6.1.4 Analyzing Crystal, suitable for the dispersion of sulfu

32、rKa and background X-rays within the angular range of thespectrometer employed. Germanium or pentaerythritol (PET)are generally found to be acceptable. Other crystals may beused, consult with the instrument vendor.6.1.5 X-ray Tube, capable of exciting sulfur Ka radiation.Tubes with anodes of rhodium

33、, chromium, and scandium aremost popular although other anodes can be used.NOTE 4Exposure to excessive quantities of high energy radiationsuch as those produced by X-ray spectrometers is injurious to health. Theoperator needs to take appropriate actions to avoid exposing any part oftheir body, not o

34、nly to primary X-rays, but also to secondary or scatteredradiation that might be present. The X-ray spectrometer should beoperated in accordance with the regulations governing the use of ionizingradiation.6.2 Analytical Balance, capable of weighing to the nearest0.1 mg and up to 100 g.TABLE 1 Concen

35、trations of Interfering SpeciesSpecies Mass % ToleratedPhosphorus 0.3Zinc 0.6Barium 0.8Lead 0.9Calcium 1Chlorine 3Oxygen 2.8FAME (see Note 16)25Ethanol (see Note 16)8.6Methanol (see Note 16)6D26220827. Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise

36、indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.3Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit

37、its use without lessening the accuracy ofthe determination.7.2 Di-n-Butyl Sulfide (DBS), a high-purity material with acertified analysis for sulfur content. Use the certified sulfurcontent and the material purity when calculating the exactconcentrations of the calibration standards (see 9.1).(Warnin

38、gDi-n-butyl sulfide is flammable and toxic. Pre-pared solutions may not be stable several months after prepa-ration.)NOTE 5It is essential to know the concentration of sulfur in thedi-n-butyl sulfide, not only the purity, since impurities may also be sulfurcontaining compounds. The sulfur content ma

39、y be determined via massdilution in sulfur-free white oil followed by a direct comparison analysisagainst NIST (or other primary standards body) reference materials.7.3 Drift Correction Monitor(s) (Optional), Several differ-ent materials have been found to be suitable for use as driftcorrection moni

40、tors. Appropriate drift monitor samples shouldbe permanent materials that are stable with respect to repeatedexposure to X-rays. Stable liquids like polysulfide oils, glass ormetallic specimens are recommended. Liquids, pressed pow-ders, and solid materials that degrade with repeated exposure toX-ra

41、ys should not be used. Examples of sulfur containingmaterials that have been found to be suitable include arenewable liquid petroleum material, a metal alloy, or a fusedglass disk. The monitors counting rate, in combination withcount time, shall be sufficient to give a relative counting errorof less

42、 than 1 %. The counting rate for the monitor sample isdetermined during calibration (see 9.4) and again at the time ofanalysis (see 10.1). These counting rates are used to calculatea drift correction factor (see 11.1).7.3.1 Drift correction is usually implemented automaticallyin software, although t

43、he calculation can readily be donemanually. For X-ray instruments that are highly stable, themagnitude of the drift correction factor may not differ signifi-cantly from unity.7.4 Polysulfide Oil, generally nonyl polysulfides containinga known percentage of sulfur diluted in a hydrocarbon matrix.(War

44、ningMay cause allergic skin reactions.)NOTE 6Polysulfide oils are high molecular weight oils that containhigh concentrations of sulfur, as high as 50 weight percent. They exhibitexcellent physical properties such as low viscosity, low volatility, anddurable shelf life while being completely miscible

45、 in white oil. Polysulfideoils are readily available commercially. The sulfur content of the polysul-fide oil concentrate is determined via mass dilution in sulfur-free white oilfollowed by a direct comparison analysis against NIST (or other primarystandards body) reference materials.7.5 Mineral Oil

46、, White (MOW), ACS Reagent Grade con-taining less than 2 mg/kg sulfur or other suitable base materialcontaining less than 2 mg/kg sulfur. When low level (1KW source) instruments are also included.14.2 BiasThe interlaboratory study6included ten NISTstandard reference materials (SRMs). The certified s

47、ulfurvalue, interlaboratory round robin (RR) value, measured C/H,apparent bias, and relative bias are given in Table 5. Table 6compares NIST value with sulfur concentrations corrected forC/H ratio. The white oil was assumed to have a C/H mass ratioof 5.698 (C22H46).14.2.1 The variation in relative s

48、ulfur sensitivity as afunction of C/H mass ratio is shown graphically in Fig. 1.14.2.2 Based on the analysis of 10 NIST Standard Refer-ence Materials (SRMs), there was no significant bias betweenthe certified values and the results obtained in this interlabo-ratory study for any SRM or sample type w

49、ithin measured6Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D02-1622.TABLE 5 Comparison of NIST SRM Data and ASTM Interlaboratory Study (RR) Measured ResultsNISTSRMNumberSulfur,mg/kg,NISTRRSampleNumberMatrixAverage Measuredmg/kg SulfurASTM RRMeasured Reproducibilitymg/kg SulfurASTM RRMeasured Biasmg/kg SulfurRelative MeasuredBias, %2298 4.7 1 Gasoline 6.0 2.9 1.3 27.72723a 11.0 5 Diesel 10.1 3.6 -0.9 -8.182299 13.6 3 Gasoline 14.2 3.8 0.6 4.412296 40.0 2 Gasoline 40.2 6.6 0.2 0.52770 41.6 7 Diesel