1、Designation: D6568 00 (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 cas
2、e 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
3、 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 safe
4、ty 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-tio
5、nal System of units (SI): the modern metric system2.2 Other Documents:ISO Guide 17025 General Requirements for the Compe-tence of Calibration and Testing Laboratories2ISO Guide 30 Terms and definitions used in connection withreference materials2International Vocabulary of Basic and General Terms inM
6、etrology VIM: ISO: 2nd ed., 199323. Terminology3.1 DefinitionsFor definitions of terms used in this Guide,refer to D1129.3.1.1 certified reference materialreference material, ac-companied by a certificate, one or more of whose propertyvalues are certified by a procedure which established itstraceabi
7、lity 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).NOTE 1There is significant variation in the overall quality of com-mercially available cert
8、ified 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.3.1.2 traceabilityproperty of the result of a measurementor the value of
9、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).3.1.3 uncertainty (of measurement)parameter, associatedwith the result of a measurement that characterizes the d
10、isper-sion of values that could reasonably be attributed to themeasured. (International Vocabulary of Basic and GeneralTerms in Metrology VIM (ISO: 2nd ed., 1993).3.1.4 work plana documented procedure intended for useby a laboratory to meet the measurement traceability require-ments of a defined nee
11、d.3.1.5 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 requiremen
12、ts 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 provi
13、des a uniform basis for thecomparison of results from different measurement systems andbecause it relates those results to our current knowledge ofphysical laws. (Note 3)NOTE 2A certified reference material traceable to SI units is acertified reference material whose value can be related with a stat
14、ed1This 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
15、 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.uncertainty t
16、hrough an unbroken change of comparisons to stated refer-ences (usually national or international standards) in SI units, such as aprimary measurement made in SI units or a national standard certified inSI units.NOTE 3Not all chemical analysis results can be traceable to SI unitsor to certified refe
17、rence 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 Proficiency Test providers can be
18、expected to reportstatistically similar results on the same sample. However, sometest methods and some certified reference materials are notsupported with data traceable to SI units. Therefore, fullycompliant laboratories that are not connected to the sameproviders may report statistically different
19、 chemical analysisresults if they used the same nontraceable test method on thesame sample. This problem could be minimized if they usedtest methods, measurement devices, and certified referencematerials that are traceable to SI units, where available.4.3 Although some standard test methods and cert
20、ifiedreference materials provide evidence of traceability to SI units,many others do not. Therefore, not all laboratories can beexpected to universally meet all requests for traceable analysesuntil the traceability of more test methods and certifiedreference materials is recognized through appropria
21、te docu-mentation.4.4 The primary significance of this guide is that it estab-lishes a consensus that, in order for a laboratory to generatetraceable measurements, it must (1) have a clear understandingof the needs of the user of the traceable measurements, (2)comply with the internationally accepte
22、d quality-system re-quirements included in ISO Guide 17025,(3) use test methods,measurement devices, and certified reference materials whichhave been shown to be traceable to SI units, and (4) be able todemonstrate that the measurement system was in statisticalcontrol at the time the measurements we
23、re made.4.5 It is expected that this guide will be used by CommitteeD19 in setting policies for the technical content of its standardsthat are designated to be usable to generate traceable chemicalanalyses.5. Summary5.1 A client shall prepare a request for traceable chemicalanalyses and submit it to
24、 an ISO Guide 17025 compliantlaboratory for review and acceptance. (Note 4)NOTE 4By reference, this guide incorporates the laboratory qualitysystem requirements of ISO Guide 17025. A laboratory that does notcomply with ISO Guide 17025 (or an equivalent quality system guide suchas the requirements do
25、cument being produced by the National Environ-mental Laboratory Accreditation Council NELAC) is considered non-compliant with this guide.5.2 The laboratory shall prepare a work plan to meet therequirements and obtain concurrence with the client.5.3 The laboratory shall make the chemical analyses and
26、issue a report.6. Procedure6.1 The client shall prepare a request for traceable measure-ments and submit it to an ISO Guide 17025 compliantlaboratory for review and acceptance, as follows.6.1.1 The request shall identify the source (i.e. the specificsampling site, the process generating the sample,
27、etc.), sam-pling history, configuration, and approximate composition ofthe test materials, the traceable measurements to be made withtheir required maximum uncertainties. It shall also identifyspecial requirements, such as, the need to certify that thematerial tested complies with a specific product
28、 specification orthat traceability must be made to a specific standard orCertified Reference Material. The request shall also specify ifany nontraceable chemical analyses are to be included as partof the project.6.1.2 The client shall select an ISO Guide 17025 compliantlaboratory and submit their re
29、quest to the laboratory for review.6.1.3 The laboratory shall review the request, work with theclient to clarify their understanding of the need, and inform theclient of its willingness and capability to proceed.6.2 The laboratory shall prepare a work plan (Note 5)tomeet the requirements and obtain
30、concurrence with the client,as follows.NOTE 5A work plan can be in the form of a laboratory SOP thatincludes the requirements detailed in sections 6.2.1-6.2.6. This will allowa laboratory to have a “generic” work plan, which will reduce costs andincrease efficiency.6.2.1 The work plan shall identify
31、 protocols: for example,sample receipt, chain of custody, and sample preparation. Itshall also identify all test methods to be used. All test methodsused for traceable measurements shall have associated docu-mentation showing their complete traceability to SI units,where applicable. Traceability can
32、 be demonstrated either bydirect measurement, use of pure materials which were assayedusing methods traceable to SI units, or use of CertifiedReference Materials which were certified in a manner traceableto SI units. If traceable standard methods are not available, theLaboratory may propose to valid
33、ate new analytical methods forthis work. The work plan shall also document how nontrace-able measurements, if required, are to be carried out.6.2.2 The work plan shall describe the anticipated measure-ment uncertainty for the project to ensure that the estimateduncertainties in the final report valu
34、es do not exceed theclients specified requirements. The statistical basis for theestimated uncertainty measurements described in the work planshould be identified, i.e. from in-house quality control data,from the precision and bias statement in the Standard TestMethod, etc.6.2.3 The work plan shall
35、identify matrix-matched certifiedreference materials that contain the relevant analyte at aconcentration representative of the expected sample concen-tration (where available) or pure chemicals to be carried alongwith the traceable measurements. It shall also specify themaximum estimated uncertainti
36、es to be permitted in makingthese measurements. The laboratory staff shall make sure thatthe maximum estimated uncertainties, either determined underthe work plan or published with a Certified Reference Materialwith similar matrix and analyte concentration (when available),D6568 00 (2011)2are attain
37、able and are small enough to permit the attainment ofthe expected values. (Note 6)NOTE 6The laboratorys ability to meet these anticipated uncertain-ties will indicate that the measurement uncertainties in the measuringlaboratory were reasonable while the traceable measurements were beingcarried out.
38、6.2.4 The work plan shall define the contents of the finalreport.6.2.5 The work plan shall be reviewed and approved forpresentation to the client by the laboratorys management. Thatreview should include projected time and cost schedules, asneeded, to meet local business needs.6.2.6 The work plan sha
39、ll be presented to the client forreview. If the client decides that revisions are needed, thoserevisions shall be reviewed and approved by the laboratorysmanagement before being presented to the client for finalacceptance. The work plan shall be accepted by the client, afterwhich the laboratory can
40、begin to carry out the work.6.3 The laboratory shall make the chemical analyses andissue a report, as follows.6.3.1 The laboratory shall make the agreed-upon chemicalanalyses and document them in accordance with the work planand ISO Guide 17025. If, in the course of making themeasurements, it become
41、s necessary to deviate from the workplan in any way that will affect the client or the clients use ofthe data, the laboratory shall inform the client. If necessary, thework plan shall be updated and approved as described in 6.2.6.3.2 When the work is complete, Staff shall prepare andissue a written
42、report that shall include all of the material andmeasurement traceability documentation described in the workplan. In the event that the work included any method validation(6.1.1) those results shall be included. The report shall alsocomply with the reporting requirements of ISO Guide 17025.(Note 7)
43、. It shall clearly differentiate between traceable andnontraceable measurements, if both were specified.NOTE 7It is recommended, but not required, that all copies of theoriginal work plan be destroyed. Since the original work plan coveredwhat was expected to occur and the final report describes what
44、 actuallyoccurred, retaining the planning document may precipitate post-completion confusion about the integrity of the final report. If desired thework plan can be marked obsolete (or similar notation) and maintained.7. Keywords7.1 certified reference materials; measurement traceabilityASTM Interna
45、tional takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely th
46、eir own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should
47、 be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standa
48、rds, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D6568 00 (2011)3
