ASTM E1621-2005 Standard Guide for X-Ray Emission Spectrometric Analysis《X射线发散光谱分析标准指南》.pdf
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1、Designation: E 1621 05Standard Guide forX-Ray Emission Spectrometric Analysis1This standard is issued under the fixed designation E 1621; 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 parent
2、heses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers guidelines for developing and de-scribing analytical procedures using a wavelength-dispersiveX-ray spectrometer.1.2 The values state
3、d in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 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
4、health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E 135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE 305 Practice for Establishing and Controlling Spectro-chemical Analytical Cur
5、ves3E 1257 Guide for Evaluating Grinding Materials Used forSurface Preparation in Spectrochemical AnalysisE 1329 Practice for Verification and the Use of ControlCharts in Spectrochemical AnalysisE 1361 Guide for Correction of Interelement Effects inX-ray Spectrometric AnalysisE 1601 Practice for Con
6、ducting an Interlaboratory Study toEvaluate the Performance of an Analytical Method3. Terminology3.1 DefinitionsFor definitions of terms used in this guide,refer to Terminologies E 135 and the terminology section ofE 1361.4. Summary of Guide4.1 The test specimen is prepared with a clean, uniform, fl
7、atsurface. It may be prepared by grinding, polishing, or lathing ametal surface or by fusing or briquetting a powder.This surfaceis irradiated with a primary source of X rays. The secondary Xrays produced in the specimen are dispersed according to theirwavelength by means of crystals or synthetic mu
8、ltilayers.Theirintensities are measured by suitable detectors at selectedwavelengths and converted to counts by the detector. Concen-trations of the elements are determined from the measuredintensities of analyte X-ray lines using analytical curvesprepared with suitable reference materials. Either a
9、 fixedmulti-channel simultaneous system or a sequential monochro-mator system may be used to provide determinations of theelements.5. Significance and Use5.1 X-ray fluorescence spectrometry can provide an accu-rate and precise determination of metallic and many non-metallic elements. This guide cove
10、rs the information thatshould be included in an X-ray spectrometric analytical methodand provides direction to the analyst for determining theoptimum conditions needed to achieve acceptable accuracy.5.2 The accuracy of an analysis is a function of thecalibration scheme, the sample preparation, and t
11、he samplehomogeneity. Close attention to all aspects of these areas isnecessary to achieve the best results.6. Interferences6.1 Line overlaps, either total or partial, may occur for someelements. Fundamental parameter equations require that the netintensities be free from line overlap effects. Some
12、empiricalschemes incorporate line overlap corrections in their equations.See Appendix X1 for correction of line overlap effects.6.2 Interelement effects or matrix effects may exist for someelements. An empirical way to compensate for these effects isto prepare a series of calibration curves that cov
13、er the desig-nated concentration ranges to be analyzed. A large suite ofcarefully designed reference materials is necessary for thisprocedure. A series of samples in which all elements arerelatively constant, except for the analyte, is necessary for eachanalyte that can be affected by other elements
14、 in the matrix. In1This guide is under the jurisdiction of ASTM Committee E01 on AnalyticalChemistry for Metals, Ores, and Related Materials and is the direct responsibility ofSubcommittee E01.20 on Fundamental Practices.Current edition approved July 15, 2005. Published August 2005. Originallyapprov
15、ed in 1994. Last previous edition approved in 1999 as E 1621 94 (1999).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 AST
16、M website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.addition, several series for the same analyte may be necessary,if the analyte is subject to large effects from some otherelement in the matrix. The composition of t
17、he specimen beinganalyzed must match closely the composition of the referencematerials used to prepare the particular calibration curves.6.2.1 Alternatively, mathematical methods may be used tocompensate for interelement or matrix effects. Various math-ematical correction procedures are commonly uti
18、lized. SeeGuide E 1361. Any of these that will achieve the necessaryanalytical accuracy is acceptable.NOTE 1Interelement effects are not interferences in the spectrometricsense, but will contribute to errors in the analysis if not properlyaddressed. Caution must be used with empirical mathematical m
19、odels tobe sure that sufficient data is provided to adequately compensate for theseeffects. Reference materials that were not used in the calibration should beanalyzed as unknowns to verify the calibration.6.3 Additionally, interferences may occur from Comptonlines or characteristic lines generated
20、by the target material ofthe X-ray tube. These may be reduced or eliminated by the useof primary beam filters, but this will cause some loss of analyteline intensity.6.4 Errors From Metallurgical StructureBecause the ana-lyte intensity is affected by the mass absorption of the sampleand mathematical
21、 models assume a homogeneous sample, anerror may result if the analyte exists in a separate phase, suchas an inclusion. For example, in a steel that contains carbon andcarbide formers such as titanium and niobium, the titaniummay exist in a titanium-niobium carbide that has a lower massabsorption co
22、efficient than iron for the titanium K-a line. Theintensity for titanium is higher in this sample than it would beif the titanium were in solid solution.7. Apparatus7.1 Specimen Preparation Equipment for Metals:7.1.1 Surface Grinder or Sander With Abrasive Belts orDisks, or Lathe, capable of providi
23、ng a flat, uniform surface onboth the reference materials and test specimens.7.1.1.1 Abrasive disks are preferred over belts because theplaten on a belt sander tends to wear and produce a convexsurface on the specimen. If belt sanders are used, care must beexercised to be sure the platen is maintain
24、ed flat.7.1.1.2 The grinding material should be selected so that nosignificant contamination occurs for the elements of interestduring the sample preparation. (Refer to Guide E 1257.)7.1.1.3 Grinding belts or disks shall be changed at regular,specified intervals in order that changes in abrasive gri
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