1、Designation: D 4927 05An American National StandardStandard Test Methods forElemental Analysis of Lubricant and Additive ComponentsBarium, Calcium, Phosphorus, Sulfur, and Zinc byWavelength-Dispersive X-Ray Fluorescence Spectroscopy1This standard is issued under the fixed designation D 4927; the num
2、ber 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 (e) indicates an editorial change since the last revision or reapproval.This st
3、andard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 These test methods cover the determination of barium,calcium, phosphorus, sulfur, and zinc in unused lubricating oilsat element concentration ranges shown in Table 1. The rangecan be extended to higher concentrati
4、ons by dilution of samplespecimens. Additives can also be determined after dilution.Two different methods are presented in these test methods.1.2 Test Method A (Internal Standard Procedure)Internalstandards are used to compensate for interelement effects ofX-ray excitation and fluorescence (see Sect
5、ions 8 through 13).1.3 Test Method B (Mathematical Correction Procedure)The measured X-ray fluorescence intensity for a given elementis mathematically corrected for potential interference fromother elements present in the sample (see Sections 14 through19).1.4 The preferred concentration units are m
6、ass % barium,calcium, phosphorus, sulfur, or zinc.1.5 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 and health practices and determine the applica-bility of r
7、egulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 6299 Practice for Applying Statistical Quality AssuranceTechniques to Evaluate Analytical Measurement SystemPerformance3. Summary of the Test Methods3.1 A sample specimen is placed in the X-ray beam and theintensity of t
8、he appropriate fluorescence lines of barium,calcium, phosphorus, sulfur, and zinc are measured. Instrumentresponse factors related to the concentration of standardsenable the determination of the concentration of elements inthe tested sample specimens. Enhancement or depression of theX-ray fluoresce
9、nce of a given element by an interferingelement in the sample may occur. Two test methods (A and B)are described for compensating any interference effect.3.2 Test Method A (Internal Standard Procedure)Internalstandards are used with the standards and sample specimens tocompensate for the potential i
10、nterelement effects.3.2.1 Barium, Calcium, Phosphorus, and ZincA samplespecimen that has been blended with a single internal standardsolution (containing tin or titanium for barium and calcium,zirconium for phosphorus, and nickel for zinc) is poured intoan X-ray cell. Total net counts (peak intensit
11、ybackground)for each element and its respective internal standard arecollected at their appropriate wavelengths. The ratios betweenelemental and internal standard counts are calculated andconverted into barium, calcium, phosphorus, or zinc concen-trations, or a combination thereof, from calibration
12、curves.3.2.2 SulfurA sample specimen is mixed with a leadinternal standard solution and analyzed as described in 3.2.1.3.3 Test Method B (Mathematical Correction Procedure)The measured intensity for a given element is mathematicallycorrected for the interference from other elements in thesample spec
13、imen. This requires that intensities from all ele-ments in the specimen be obtained.3.3.1 The sample specimen is placed in the X-ray beam andthe intensities of the fluorescence lines of barium, calcium,phosphorus, sulfur, and zinc are measured. A similar measure-ment is made away from the fluorescen
14、ce lines in order toobtain a background correction. Concentrations of the elements1These test methods are under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and are the direct responsibility of Subcommit-tee D02.03 on Elemental Analysis.Current edition approved April 1,
15、 2005. Published April 2005. Originallyapproved in 1989. Last previous edition approved in 2002 as D 4927 02.2For 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 sta
16、ndards Document Summary page onthe ASTM website.TABLE 1 Range of ApplicabilityElement Range, Mass %Barium 0.04-8.5Calcium 0.01-1.0Phosphorus 0.01-0.5Sulfur 0.1-4.0Zinc 0.01-0.61*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO B
17、ox C700, West Conshohocken, PA 19428-2959, United States.of interest are determined by comparison of net signals againstappropriate interelement correction factors developed fromresponses of calibration standards.3.3.2 The X-ray fluorescence spectrometer is initially cali-brated with a suite of stan
18、dards in order to determine byregression analysis, interelement correction factors and instru-ment response factors.3.3.3 Subsequent calibration is achieved using a smallernumber of standards since only the instrument response factorsneed to be redetermined. One of these standards (or an optionalsyn
19、thetic pellet) can be used to monitor instrumental drift whenperforming a high volume of analyses.3.4 Additives and additive packages can be determined afterdilution with base oil to place the elemental concentrations inthe range described in 1.1.4. Significance and Use4.1 Some oils are formulated w
20、ith organo-metallic additiveswhich act as detergents, antioxidants, antiwear agents, and soforth. Some of these additives contain one or more of theseelements: barium, calcium, phosphorus, sulfur, and zinc. Thesetest methods provide a means of determining the concentrationof these elements which in
21、turn provides an indication of theadditive content of these oils.5. Interferences5.1 The additive elements found in lubricating oils willaffect the measured intensities from the elements of interest toa varying degree. In general for lubricating oils, the X-radiationemitted by the element of interes
22、t is absorbed by the otherelements in the sample matrix. Also, the X-radiation emittedfrom one element can further excite another element. Theseeffects are significant at concentrations varying from 0.03mass % due to the heavier elements to 1 mass % for the lighterelements. The measured intensity fo
23、r a given element can bemathematically corrected for the absorption of the emittedradiation by the other elements present in the sample specimen.Suitable internal standards can also compensate for X-rayinter-element effects. If an element is present at significantconcentrations and an interelement c
24、orrection for that elementis not employed, the results can be low due to absorption orhigh due to enhancement.6. Apparatus6.1 X-Ray Spectrometer, equipped for soft X-ray detectionof radiation in the range from 1 to 10 A. For optimumsensitivity, the spectrometer is equipped with the following:6.1.1 X
25、-Ray Generating Tube, with chromium, rhodium, orscandium target. Other targets can also be employed.6.1.2 Helium, purgeable optical path.6.1.3 Interchangeable Crystals, germanium, lithium fluo-ride (LiF200), graphite, or polyethylene terephthalate (PET), ora combination thereof. Other crystals can a
26、lso be used.6.1.4 Pulse-Height Analyzer, or other means of energydiscrimination.6.1.5 Detector, flow proportional, or scintillation, or flowproportional and scintillation counter.6.2 Shaker, Mechanical Stirrer, or Ultrasonic Bath, capableof handling from 30-mL to 1-L bottles.6.3 X-Ray Disposable Pla
27、stic Cells, with suitable filmwindow. Suitable films include Mylar,3polypropylene, orpolyimid with film thicknesses between 0.25 to 0.35 mil (6.3 to8.8 m).NOTE 1Some films contain contamination of the elements of interest(Mylar in particular). The magnitude of the contamination is assessed andthe sa
28、me film batch used throughout the entire analysis.7. Purity of Reagents7.1 Reagent grade chemicals shall be used in all tests.Unless otherwise indicated, it is intended that all reagents shallconform to the specifications of the Committee on AnalyticalReagents of the American Chemical Society, where
29、 suchspecifications are available.4Other grades may be used, pro-vided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.TEST METHOD A (INTERNAL STANDARDPROCEDURE)8. Reagents and Materials8.1 Helium, for optica
30、l path of spectrometer.8.2 P-10 Ionization Gas, 90 volume % argon and 10 volume% methane for the flow proportional counter.8.3 Diluent Solvent, a suitable solvent free of metals, sulfur,and phosphorus (for example, kerosine, white oil, or xylenes).8.4 Internal Standard Materials:8.4.1 Nickel Octoate
31、, preferably containing 5.0 6 0.1mass % nickel. If the nickel concentration is higher or lower(minimum concentration that can be used is 2.5 6 0.1 mass %nickel), the laboratory needs to adjust the amount of sampletaken in 9.1 to yield an equivalent nickel concentration level inthe internal standard.
32、 Other nickel-containing organic matrices(free of other metals, sulfur, and phosphorus) may be substi-tuted provided the nickel is stable in solution, the concentrationis known ($2.5 6 0.1 mass % nickel), and the laboratory canadjust the amount of sample taken in 9.1 to yield an equivalentnickel con
33、centration level in the internal standard if the nickelconcentration does not initially contain 5.0 6 0.1 mass %nickel.NOTE 2Many X-ray tubes emit copper X rays which increase inintensity with age. This does not present a problem when using copper asan internal standard for zinc providing that frequ
34、ent calibrations areperformed. No problem exists when using nickel as internal for zinc andnickel is the preferred internal standard material.8.4.2 Titanium 2-Ethylhexoide or Tin Octoate, preferablycontaining 8.0 6 0.1 mass % titanium or tin. If the titanium ortin concentration is higher or lower (m
35、inimum concentrationthat can be used is 4.0 6 0.1 mass % titanium or tin), thelaboratory needs to adjust the amount of sample taken in 9.1 to3A registered trademark of E. I. du Pont de Nemours and Co.4Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington,
36、 DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D4927052yield an
37、 equivalent titanium or tin concentration level in theinternal standard. Other titanium or tin containing organicmatrices (free of other metals, sulfur, and phosphorus) may besubstituted, provided the titanium or tin is stable in solution,the concentration is known ($4.0 6 0.1 mass % titanium ortin)
38、, and the laboratory can adjust the amount of sample takenin 9.1 to yield an equivalent titanium or tin concentration levelin the internal standard if the titanium or tin concentration doesnot initially contain 8.0 6 0.1 mass % titanium or tin.8.4.3 Zirconium Octoate, preferably containing 12.0 6 0.
39、1mass % zirconium. If the laboratory uses zirconium octoatewith a lower mass % zirconium concentration level, the labo-ratory needs to evaporate away the petroleum solvent to yielda solution that contains 12.0 6 0.1 mass % zirconium. Otherzirconium containing organic matrices (free of other metals,s
40、ulfur, and phosphorus) may be substituted, provided thezirconium is stable in solution and the concentration is knownand does not exceed 12.0 6 0.1 mass % zirconium. If thezirconium concentration is 12.0 6 0.1 mass %, the laboratoryneeds to evaporate away the petroleum solvent to yield asolution tha
41、t contains 12.0 6 0.1 mass % zirconium.8.4.4 Lead Naphthenate, containing 24.0 6 0.1 mass %lead.8.5 Calibration Standard Materials:NOTE 3In addition to calibration standards identified in 8.5.1-8.5.5,single-element or multielement calibration standards may also be preparedfrom materials similar to t
42、he samples being analyzed, provided thecalibration standards to be used have previously been characterized byindependent primary (for example, gravimetric or volumetric) analyticaltechniques to establish the elemental concentration mass % levels.8.5.1 Barium 2-Ethylhexoide or Sulfonate, with concent
43、ra-tions $4 mass % barium and certified to better than 60.1 %absolute (95 % confidence limit), so that calibration standardscan be prepared as stated in 10.1.1 and 10.1.2.8.5.2 Calcium Octoate or Sulfonate, with concentrations $4 mass % calcium and certified to better than 60.1 % absolute(95 % confi
44、dence limit), so that calibration standards can beprepared as stated in 10.1.1 and 10.1.2.8.5.3 Bis(2-Ethylhexyl)Hydrogen Phosphate, 97 % purity(9.62 mass % phosphorus). Other phosphorus containing or-ganic matrices (free of other metals) may be substitutedprovided the phosphorus is stable in soluti
45、on and the concen-tration is $4 mass % phosphorus and certified to better than60.1 % absolute (95 % confidence limit), so that calibrationstandards can be prepared as stated in 10.1.1 and 10.1.2.8.5.4 Zinc Sulfonate or Octoate, with concentration $4mass % zinc and certified to better than 60.1 % abs
46、olute (95 %confidence limit), so that calibration standards can be preparedas stated in 10.1.1 and 10.1.2.8.5.5 Di-n-Butyl Sulfide, 97 % purity, (21.9 mass % sulfur).Other sulfur containing organic matrices (free of metals) maybe substituted, provided the sulfur is stable in solution and theconcentr
47、ation is $2 mass % sulfur and certified to better than60.1% absolute (95 % confidence limit), so that calibrationstandards can be prepared as stated in 10.1.2.8.6 Quality Control (QC) Samples, preferably are portionsof one or more lubricating oils or additives that are stable andrepresentative of th
48、e samples of interest. These QC samplescan be used to check the validity of the testing process andperformance of the instrument as described in Section 12.9. Preparation of Internal Standards9.1 Barium, Calcium, Phosphorus, and ZincDispense 2406 0.5 g of nickel octoate (5.0 6 0.1 mass % nickel), 30
49、 6 0.1g of titanium 2-ethylhexoide (8.0 6 0.1 mass % titanium) or 306 0.1 g of tin octoate (8.0 6 0.1 mass % tin), and 450 6 1gof diluent solvent into a 1-L bottle. Shake or stir the bottle fora minimum of 10 min. If the laboratory uses internal materialsthat have different elemental concentrations than those explic-itly stated in 8.4.1 and 8.4.2, it will be necessary for thelaboratory to adjust the amount of sample taken in order toobtain an equivalent elemental concentration in the internalstandard blend that is prepared according to the followingequations:A 5 240 3 5
