1、Designation: D6568 00 (Reapproved 2018)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, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.3 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of
5、International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:D1129 Terminology Relating to WaterD6362 Practice for Certificates of Reference Materials forWater AnalysisIEEE/ASTM SI 101
6、997 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 Connectionwith Reference Materials2VIM International
7、Vocabulary of Basic and General Termsin Metrology, ISO: 2nd ed., 199323. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard, refer toTerminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 certified reference material, nreference material,accompanied b
8、y 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
9、 Guide 303.2.1.1 DiscussionThere is significant variation in theoverall quality of commercially available certified referencematerials and caution should be used when choosing certifiedreference materials. Use Practice D6362 to provide guidance asto what information needs to be included on Certifica
10、te of acertified reference material.3.2.2 SI units, nthis 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 in ASTM BOS Volumes 11.01 and 11.02.3.2.3 traceability, nproperty of the result of a meas
11、ure-ment or the value of a standard whereby it can be related, witha stated uncertainty, to stated references, usually national orinternational standards, through an unbroken chain ofcomparisons. ISO Guide 303.2.4 uncertainty (of measurement), nparameter, associ-ated with the result of a measurement
12、 that characterizes thedispersion of values that could reasonably be attributed to themeasured. VIM3.2.5 work plan, na documented procedure intended foruse by a laboratory to meet the measurement traceabilityrequirements of a defined need.4. Significance and Use4.1 This guide establishes basic requi
13、rements 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 1) or certified reference1This guide is under the jurisdiction of ASTM Committee D19 on Water and isthe direct respon
14、sibility of Subcommittee D19.02 on Quality Systems, Specification,and Statistics.Current edition approved Aug. 1, 2018. Published September 2018. Originallyapproved in 2000. Last previous edition approved in 2011 as D6568 00 (2011).DOI: 10.1520/D6568-00R18.2Available from American National Standards
15、 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 StatesThis international standard was developed in accordance with internationally recognized principles on s
16、tandardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1materials traceable to SI units. Traceability of chemical analy-ses is important beca
17、use 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 2).NOTE 1Acertified reference material traceable to SI units is a certifiedreference material whose value can be related
18、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.NOTE 2Not all chemical analysis results can be traceable to SI
19、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 Proficien
20、cy Test providers can be 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 repor
21、t statistically different 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 stand
22、ard test methods and certifiedreference 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 rec
23、ognized through appropriate 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 th
24、e internationally accepted 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 th
25、e time the measurements were 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 chemica
26、lanalyses and submit it to an ISO Guide 17025 compliantlaboratory for review and acceptance (Note 3).NOTE 3By 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
27、suchas the requirements document 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
28、 the chemical analyses andissue 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 (that is, thespecific sampling site, the p
29、rocess generating the sample, etc.),sampling history, configuration, and approximate compositionof the test materials, the traceable measurements to be madewith their required maximum uncertainties. It shall also iden-tify special requirements, such as, the need to certify that thematerial tested co
30、mplies with a specific product specification orthat traceability must be made to a specific standard or certifiedreference material. The request shall also specify if anynontraceable chemical analyses are to be included as part of theproject.6.1.2 The client shall select an ISO Guide 17025 compliant
31、laboratory and submit their request 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 4)tomee
32、t the requirements and obtain concurrence with the client,as follows.NOTE 4A work plan can be in the form of a laboratory standardoperating procedure (SOP) that includes the requirements detailed insections 6.2.1 6.2.6. This will allow a laboratory to have a “generic”work plan, which will reduce cos
33、ts and increase efficiency.6.2.1 The work plan shall identify 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 complet
34、e traceability to SI units,where applicable. Traceability can 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
35、methods are not available, thelaboratory may propose to validate 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 en
36、sure that the estimateduncertainties in the final report values do not exceed the clientsspecified requirements. The statistical basis for the estimateduncertainty measurements described in the work plan should beidentified, that is, from in-house quality control data, from theprecision and bias sta
37、tement in the standard test method, etc.6.2.3 The work plan shall 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 me
38、asurements. It shall also specify themaximum estimated uncertainties to be permitted in makingD6568 00 (2018)2these measurements. The laboratory staff shall make sure thatthe maximum estimated uncertainties, either determined underthe work plan or published with a certified reference materialwith si
39、milar matrix and analyte concentration (when available),are attainable and are small enough to permit the attainment ofthe expected values (Note 5).NOTE 5The laboratorys ability to meet these anticipated uncertaintieswill indicate that the measurement uncertainties in the measuring labora-tory were
40、reasonable while the traceable measurements were being carriedout.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 schedul
41、es, asneeded, to meet local business needs.6.2.6 The work plan shall 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 pl
42、an shall be accepted by the client, afterwhich the laboratory can 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 G
43、uide 17025. If, in the course of making themeasurements, it becomes 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
44、When the work is complete, staff shall prepare andissue a written 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 also
45、comply with the reporting requirements of ISO Guide 17025(Note 6). It shall clearly differentiate between traceable andnontraceable measurements, if both were specified.NOTE 6It is recommended, but not required, that all copies of theoriginal work plan be destroyed. Since the original work plan cove
46、redwhat was expected to occur and the final report describes what 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 ce
47、rtified reference materials; measurement traceabilityASTM International 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 ri
48、ghts, and the riskof infringement of such rights, are entirely their 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 fo
49、r revision of this standard or for additional standardsand should 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 Standards, 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 mu
