ASTM D6568-00(2006)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D6568–00 (Reapproved 2006)
Standard Guide for
Planning, Carrying Out, and Reporting Traceable Chemical
Analyses of Water Samples
This standard is issued under the fixed designation D6568; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope property values are expressed, and for which each certified
value is accompanied by an uncertainty at a stated level of
1.1 This guide sets a protocol for generating and reporting
confidence. (ISO Guide 30:1992) (Note 1).
chemical analyses that are traceable to SI Units or to Certified
Reference Materials in laboratories that serve the water and
NOTE 1—There is significant variation in the overall quality of com-
environmental industry. mercially available Certified Reference Materials and caution should be
used when choosing Certified Reference Materials. Use ASTM D6362 to
1.2 This standard does not purport to address all of the
provide guidance as to what information needs to be included on
safety concerns, if any, associated with its use. It is the
Certificate of a Certified Reference Material.
responsibility of the user of this standard to establish appro-
3.1.2 traceability—property of the result of a measurement
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. or the value of a standard whereby it can be related, with a
stated uncertainty, to stated references, usually national or
2. Referenced Documents
international standards, through an unbroken chain of compari-
2.1 ASTM Standards: sons. (ISO Guide 30:1992).
D1129 Terminology Relating to Water 3.1.3 uncertainty (of measurement)—parameter, associated
D6362 Practice for Certificates of Reference Materials for with the result of a measurement that characterizes the disper-
Water Analysis sion of values that could reasonably be attributed to the
IEEE/ASTM SI 10–1997 Standard for use of the Interna- measured. (International Vocabulary of Basic and General
tional System of Units (SI): the modern metric system Terms in Metrology [VIM] (ISO: 2nd ed., 1993).
2.2 Other Documents: 3.1.4 work plan—a documented procedure intended for use
ISO Guide 17025: General Requirements for the Compe- by a laboratory to meet the measurement traceability require-
tence of Calibration and Testing Laboratories ments of a defined need.
ISO Guide 30: Terms and definitions used in connection 3.1.5 SI units—this is the International System of Units (SI)
with reference materials which is the modernized Metric System as described in
International Vocabulary of Basic and General Terms in IEEE/ASTM SI 10–1997. A SI Quick Reference Guide is
Metrology [VIM]: ISO: 2nd ed., 1993 includedattheback(inthe“graypages”)ofvolumes11.01and
11.02.
3. Terminology
4. Significance and Use
3.1 Definitions—For definitions of terms used in this Guide,
refer to D1129, Terminology Relating to Water. 4.1 This Guide establishes basic requirements which should
3.1.1 certified reference material—reference material, ac- be met by water and environmental laboratories that generate
companied by a certificate, one or more of whose property and report test chemical analyses which the laboratory client
values are certified by a procedure which established its desires to be traceable to SI Units (Note 2) or Certified
traceability to an accurate realization of the unit in which the Reference Materials traceable to SI Units. Traceability of
chemical analyses is important because it provides a uniform
basis for the comparison of results from different measurement
This guide is under the jurisdiction of ASTM Committee D19 on Water and is
systems and because it relates those results to our current
the direct responsibility of Subcommittee D19.02 on General Specifications,
knowledge of physical laws. (Note 3)
Technical Resources, and Statistical Methods.
Current edition approved Feb. 15, 2006. Published February 2006. Originally
NOTE 2—A Certified Reference Material traceable to SI Units is a
approved in 2000. Last previous edition approved in 2000 as D6568 – 00. DOI:
Certified Reference Material whose value can be related with a stated
10.1520/D6568-00R06.
Available from American National Standards Institute, 25 West 43rd St., 4th
Floor, New York, New York, 10036
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D6568–00 (2006)
uncertainty through an unbroken change of comparisons to stated refer-
6. Procedure
ences (usually national or international standards) in SI Units, such as a
6.1 The client shall prepare a request for traceable measure-
primary measurement made in SI Units or a national standard certified in
ments and submit it to an ISO Guide 17025 compliant
SI Units.
laboratory for review and acceptance, as follows.
NOTE 3—Not all chemical analysis results can be traceable to SI Units
6.1.1 The request shall identify the source (i.e. the specific
or to Certified Reference Material’s traceable to SI Units, such as
sampling site, the process generating the sample, etc.), sam-
Turbidity and or Total Suspended Solids.
pling history, configuration, and approximate composition of
4.2 Many waters-related laboratories comply with ISO
the test materials, the traceable measurements to be made with
Guide 17025 and participate in Proficiency Testing Programs.
their required maximum uncertainties. It shall also identify
Laboratories that are connected to the same accreditation
special requirements, such as, the need to certify that the
bodies and ProficiencyTest providers can be expected to report
materialtestedcomplieswithaspecificproductspecificationor
statistically similar results on the same sample. However, some
that traceability must be made to a specific standard or
test methods and some Certified Reference Materials are not
Certified Reference Material. The request shall also specify if
supported with data traceable to SI Units. Therefore, fully
any nontraceable chemical analyses are to be included as part
compliant laboratories that are not connected to the same
of the project.
providers may report statistically different chemical analysis
6.1.2 The client shall select an ISO Guide 17025 compliant
results if they used the same nontraceable test method on the laboratoryandsubmittheirrequesttothelaboratoryforreview.
same sample. This problem could be minimized if they used
6.1.3 The laboratory shall review the request, work with the
test methods, measurement devices, and Certified Reference client to clarify their understanding of the need, and inform the
Materials that are traceable to SI Units, where available. client of its willingness and capability to proceed.
6.2 The laboratory shall prepare a work plan (Note 5)to
4.3 Although some standard test methods and Certified
meet the requirements and obtain concurrence with the client,
Reference Materials provide evidence of traceability to SI
as follows.
Units, many others do not. Therefore, not all laboratories can
be expected to universally meet all requests for traceable
NOTE 5—A Work Plan can be in the form of a laboratory SOP that
analyses until the traceability of mo
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