ASTM_D_4927_-_15.pdf

Designation:D492715Standard 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 D4927;the number 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.This standard has been approved for use by agencies of the U.S.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 concentrations 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 Sections 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 mass%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 regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System Performance3.Summary of the Test Methods3.1 A sample specimen is placed in the X-ray beam and theintensity of the 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 fluorescence 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 interelement 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 intensitybackground)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 zincconcentrations,or a combination thereof,from calibrationcurves.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 specimen.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 fluorescence lines in order toobtain a background correction.Concentrations of the elementsof interest are determined by comparison of net signals againstappropriate interelement correction factors developed fromresponses of calibration standards.1These test methods are under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and are the direct responsibilityof Subcommittee D02.03 on Elemental Analysis.Current edition approved Dec.1,2015.Published December 2015.Originallyapproved in 1989.Last previous edition approved in 2014 as D4927 14.DOI:10.1520/D4927-15.2For 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 standards Document Summary page onthe ASTM website.*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 States1 3.3.2 The X-ray fluorescence spectrometer is initially cali-brated with a suite of standards in order to determine byregression analysis,interelement correction factors an