ASTM_D_6568_-_00_2011.pdf

Designation:D656800(Reapproved 2011)Standard Guide forPlanning,Carrying Out,and Reporting Traceable ChemicalAnalyses of Water Samples1This standard is issued under the fixed designation D6568;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.1.Scope1.1 This guide sets a protocol for generating and reportingchemical analyses that are traceable to SI units or to certifiedreference materials in laboratories that serve the water andenvironmental industry.1.2 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:D1129 Terminology Relating to WaterD6362 Practice for Certificates of Reference Materials forWater AnalysisIEEE/ASTM SI 101997 Standard for use of the Interna-tional System of units(SI):the modern metric system2.2 Other Documents:ISO Guide 17025 General Requirements for the Competenceof Calibration and Testing Laboratories2ISO Guide 30 Terms and definitions used in connection withreference materials2International Vocabulary of Basic and General Terms inMetrology VIM:ISO:2nd ed.,199323.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this Guide,refer toD1129.3.1.2 certified reference materialreference material,ac-companied by a certificate,one or more of whose propertyvalues are certified by a procedure which established itstraceability to an accurate realization of the unit in which theproperty values are expressed,and for which each certifiedvalue is accompanied by an uncertainty at a stated level ofconfidence.(ISO Guide 30)(Note 1).NOTE1There is significant variation in the overall quality ofcommercially available certified reference materials and caution should beused when choosing certified reference materials.Use Practice D6362 toprovide guidance as to what information needs to be included onCertificate of a certified reference material.3.1.3 traceabilityproperty of the result of a measurementor the value of a standard whereby it can be related,with astated uncertainty,to stated references,usually national orinternational standards,through an unbroken chain of compari-sons.(ISO Guide 30).3.1.4 uncertainty(of measurement)parameter,associatedwith the result of a measurement that characterizes the disper-sion of values that could reasonably be attributed to themeasured.(International Vocabulary of Basic and GeneralTerms in Metrology VIM(ISO:2nd ed.,1993).3.1.5 work plana documented procedure intended for useby a laboratory to meet the measurement traceability require-ments of a defined need.3.1.6 SI unitsthis is the International System of Units(SI)which is the modernized Metric System as described inIEEE/ASTM SI 101997.A SI Quick Reference Guide isincluded at the back(in the“gray pages”)of volumes 11.01 and11.02.4.Significance and Use4.1 This guide establishes basic requirements which shouldbe met by water and environmental laboratories that generateand report test chemical analyses which the laboratory clientdesires to be traceable to SI units(Note 2)or certified referencematerials traceable to SI units.Traceability of chemical analy-ses is important because it provides a uniform basis for thecomparison of results from different measurement systems andbecause it relates those results to our current knowledge ofphysical laws.(Note 3)NOTE2Acertified reference material traceable to SI units is a certifiedreference material whose value can be related with a stated uncertaintythrough an unbroken change of comparisons to stated references(usuallynational or international standards)in SI units,such as a primarymeasurement made in SI units or a national standard certified in SI units.1This guide is under the jurisdiction of ASTM Committee D19 on Water and isthe direct responsibility of Subcommittee D19.02 on Quality Systems,Specification,and Statistics.Current edition approved May 1,2011.Published June 2011.Originallyapproved in 2000.Last previous edition approved in 2006 as D6568 00(2006).DOI:10.1520/D6568-00R11.2Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 NOTE3Not all chemical analysis results can be traceable to SI unitsor to certified reference materials traceable to SI units,such as turbidityand or total suspended solids.4.2 Many waters-related laboratories comply with ISOGuide 17025 and participate in Proficiency Testing Programs.Laboratories that are connected to the same accreditationbodies and Proficie