ASTM_E_2165_-_01.pdf

Designation:E 2165 01Standard Practice forEstablishing an Uncertainty Budget for the ChemicalAnalysis of Metals,Ores,and Related Materials1This standard is issued under the fixed designation E 2165;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice describes a model for establishing ISO17025-compliant uncertainty budgets for the chemical analysisof metals,ores,and related materials.It is based on applyingthe Horwitz2function to widely accepted,diverse interlabora-tory test programs,such as interlaboratory testing of standardtest methods and proficiency testing programs.This functionexpresses the interlaboratory standard deviations that can beexpected for any concentration level as competent laboratoriesuse optimized test procedures to analyze any matrix for anyanalyte.It may be used to set aim uncertainties against whichto plan new standard test methods and to assess the perfor-mance of existing test methods.1.2 An optimized test procedure is one in which the finaltest results are at least equivalent to alternative,state-of-the-artprocedures.In the analytical chemistry community,this meansthat calibrations are carried out,verified,and controlled suchthat the final test results have no systematic,detectable bias.The elimination of sources of bias is a key responsibility of anyperson who designs analytical test methods.Hence,an analyti-cal test method that contains systematic,measurable sources ofbias would probably not be accepted as an ASTM test methodand its performance data would probably not be in compliancewith the procedures described in this practice.1.3 The uncertainty budget model described in this practiceis based on the assumption that,in a normally distributed,bias-free environment,measurement uncertainty will improveby the square root of two with each removal of a significantsource of variation.Conversely,it is assumed that measure-ment uncertainty will worsen by the same amount with eachaddition of a significant source of variation.Furthermore,thismodel assumes that the hierarchy of increasing variation in anycomposition-based measurement system begins with calibra-tion and progresses through control to intralaboratory standarddeviation to interlaboratory standard deviation to productsampling for conformity assessment.Therefore,aim values forthe expected uncertainties at any process step can be predictedusing this model.1.4 When using this model,the aim values generated usingthis model must then be validated,verified,and documented aspart of the development and interlaboratory testing of any newtest method,sampling practice,and product specification,asappropriate.It is also expected that each laboratory that electsto use that standard test method will generate data to show thatthe standard test method complies with the published uncer-tainties developed during interlaboratory testing of the standardtest method.The principles in this practice can also be appliedto the development of test methods used to determine thecomposition of other materials.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:E 135 Terminology Relating to Analytical Chemistry forMetals,Ores and Related Materials3E 1282 Guide for Specifying the Chemical Compositionsand Selecting Sampling Practices and Quantitative Analy-sis Methods for Metals,Ores,and Related Materials3E 1329 Practice for Verification and Use of Control Chartsin Spectrochemical Analysis3E 1601 Practice for Conducting an Interlaboratory Study toEvaluate the Performance of an Analytical Method3E 2027 Practice for Conducting Proficiency Tests in theChemicalAnalysis of Metals,Ores,and Related Materials4E 2053 Guide for Planning,Carrying Out,and ReportingTraceable Chemical Analyses of Metals,Ores,and RelatedMaterials4E 2093 Guide for Optimizing,Controlling and ReportingTest Method Uncertainties from Multiple Workstations inthe Same Laboratory Organization42.2ISO Standards:1This practice is under the jurisdiction of ASTM Committee E01 on AnalyticalChemistry for Metals,Ores,and Related Materials and is the direct responsibility ofSubcommittee E01.22 on Statistics and Quality Control.Current edition approved November 10,2001.Published January 2002.2Horwitz,W.,Analytical Chemistry,Vol 54,pp.67A-76A,1982.3Annual Book of ASTM Standards,Vol 03.05.4Annual Book of ASTM Standards,Vol 03.06.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.ISO 17025(1999)General Requirements for the Com