ASTM D6568-00(2011)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D6568 − 00 (Reapproved 2011)
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) (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
commercially available certified reference materials and caution should be
environmental industry.
used when choosing certified reference materials. Use Practice 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-
3.1.3 traceability—property of the result of a measurement
priate safety and health practices and determine the applica-
or the value of a standard whereby it can be related, with a
bility of regulatory limitations prior to use.
stated uncertainty, to stated references, usually national or
international standards, through an unbroken chain of compari-
2. Referenced Documents
sons. (ISO Guide 30).
2.1 ASTM Standards:
3.1.4 uncertainty (of measurement)—parameter, associated
D1129 Terminology Relating to Water
with the result of a measurement that characterizes the disper-
D6362 Practice for Certificates of Reference Materials for
sion of values that could reasonably be attributed to the
Water Analysis
measured. (International Vocabulary of Basic and General
IEEE/ASTM SI 10–1997 Standard for use of the Interna-
Terms in Metrology [VIM] (ISO: 2nd ed., 1993).
tional System of units (SI): the modern metric system
3.1.5 work plan—a documented procedure intended for use
2.2 Other Documents:
by a laboratory to meet the measurement traceability require-
ISOGuide17025 GeneralRequirementsfortheCompetence
ments of a defined need.
of Calibration and Testing Laboratories
ISO Guide 30 Terms and definitions used in connection with 3.1.6 SI units—this is the International System of Units (SI)
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:
3.1.1 For definitions of terms used in this Guide, refer to
4.1 This guide establishes basic requirements which should
D1129.
be met by water and environmental laboratories that generate
3.1.2 certified reference material—reference material, ac-
and report test chemical analyses which the laboratory client
companied by a certificate, one or more of whose property
desirestobetraceabletoSIunits(Note2)orcertifiedreference
values are certified by a procedure which established its
materials traceable to SI units. Traceability of chemical analy-
traceability to an accurate realization of the unit in which the
ses is important because it provides a uniform basis for the
comparison of results from different measurement systems and
because it relates those results to our current knowledge of
This guide is under the jurisdiction of ASTM Committee D19 on Water and is
thedirectresponsibilityofSubcommitteeD19.02onQualitySystems,Specification, physical laws. (Note 3)
and Statistics.
NOTE2—AcertifiedreferencematerialtraceabletoSIunitsisacertified
Current edition approved May 1, 2011. Published June 2011. Originally
reference material whose value can be related with a stated uncertainty
approved in 2000. Last previous edition approved in 2006 as D6568 – 00 (2006).
through an unbroken change of comparisons to stated references (usually
DOI: 10.1520/D6568-00R11.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., national or international standards) in SI units, such as a primary
4th Floor, New York, NY 10036, http://www.ansi.org. measurement made in SI units or a national standard certified in SI units.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6568 − 00 (2011)
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 turbidity
sampling site, the process generating the sample, etc.), sam-
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.
4.3 Although some standard test methods and certified
6.2 The laboratory shall prepare a work plan (Note 5)to
reference materials provide evidence of traceability to SI units,
meet the requirements and obtain concurrence with the client,
many others do not. Therefore, not all laboratories can be
as follows.
expected to universally meet all requests for traceable analyses
NOTE 5—A work plan can be in the form of a laboratory SOP that
until the traceability of more test methods and certified
includestherequirementsdetailedinsections6.2.1–6.2.6.Thiswillallow
reference materials is recognized through appropriate docu-
a laboratory to have a “generic” work plan, which will reduce costs and
mentation.
incr
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