ASTM D3975-93(2008)
(Practice)Standard Practice for Development and Use (Preparation) of Samples for Collaborative Testing of Methods for Analysis of Sediments
Standard Practice for Development and Use (Preparation) of Samples for Collaborative Testing of Methods for Analysis of Sediments
SIGNIFICANCE AND USE
The objective of this practice is to provide guidelines for the preparation of samples for use in collaborative tests, to evaluate methods during their development, and for the evaluation of the precision and bias of proposed test methods.
Statements of the precision and bias are a mandatory part of ASTM test methods. Such an evaluation is necessary to provide guidance to the user as to the reliability of measurements that can be expected by its use. The statements are developed on the basis of user experience (ordinarily collaborative tests) with the test method.
The availability of test samples is a key requirement for collaborative evaluation of test methods.
SCOPE
1.1 This practice establishes uniform general procedures for the development, (preparation) and use of samples in the collaborative testing of methods for chemical analysis of sediments and similar materials.
1.2 The principles of this practice are applicable to aqueous samples with suitable technical modifications.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
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Designation: D3975 − 93(Reapproved 2008)
Standard Practice for
Development and Use (Preparation) of Samples for
Collaborative Testing of Methods for Analysis of Sediments
This standard is issued under the fixed designation D3975; 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 of test methods.These samples should be typical in all respects
to the sample for which the test method is applicable. Samples
1.1 This practice establishes uniform general procedures for
with three levels of concentration of the measurand are
the development, (preparation) and use of samples in the
recommended to evaluate the linearity of the test method.
collaborative testing of methods for chemical analysis of
Acceptable test materials, in order of preference are: three
sediments and similar materials.
samples of different compositions; mixtures of two samples to
1.2 The principles of this practice are applicable to aqueous
obtain the desired concentration levels; samples prepared by
samples with suitable technical modifications.
dilution of a single sample.
1.3 This standard does not purport to address all of the
4.2 In the absence of samples of known composition, the
safety concerns, if any, associated with its use. It is the
use of the spiking technique, in which standard additions of
responsibility of the user of this standard to establish appro-
knownconstituentsaremadebyestablishedtechniques,willbe
priate safety and health practices and determine the applica-
acceptable for evaluating the linearity and the bias of test
bility of regulatory limitations prior to use.
methods. In such a case, the bias statement will consist of the
accuracy of recovery of the spike.
2. Referenced Documents
4.3 Comparison of a candidate test method with a standard
2.1 ASTM Standards:
test method of known precision and bias will constitute an
D596 Guide for Reporting Results of Analysis of Water
acceptable technique for evaluation of precision and bias. In
D1129 Terminology Relating to Water
such comparative measurements, any convenient test samples
D2777 Practice for Determination of Precision and Bias of
may be used, provided they are shown to be stable during the
Applicable Test Methods of Committee D19 on Water
time required to make the intercomparison, and that the
D3670 Guide for Determination of Precision and Bias of
measurement sequences are chosen to minimize or eliminate
Methods of Committee D22
errors due to sample instability.
D3976 Practice for Preparation of Sediment Samples for
Chemical Analysis
5. Significance and Use
E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method 5.1 Theobjectiveofthispracticeistoprovideguidelinesfor
the preparation of samples for use in collaborative tests, to
3. Terminology
evaluate methods during their development, and for the evalu-
3.1 Definitions—For definition of terms used in this
ation of the precision and bias of proposed test methods.
practice, refer to Terminology D1129.
5.2 Statements of the precision and bias are a mandatory
part ofASTM test methods. Such an evaluation is necessary to
4. Summary of Practice
provide guidance to the user as to the reliability of measure-
4.1 Test samples of adequately defined composition and
ments that can be expected by its use. The statements are
homogeneity are required for evaluating the precision and bias
developed on the basis of user experience (ordinarily collab-
orative tests) with the test method.
This practice is under the jurisdiction of ASTM Committee D19 on Water and
is the direct responsibility of Subcommittee D19.07 on Sediments, Geomorphology, 5.3 The availability of test samples is a key requirement for
and Open-Channel Flow.
collaborative evaluation of test methods.
Current edition approved Oct. 1, 2008. Published November 2008. Originally
approved in 1980. Last previous edition approved in 2003 as D3975 – 93 (2003).
6. Rationale
DOI: 10.1520/D3975-93R08.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
6.1 The use of materials of demonstrated adequate homo-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
geneity and known composition enable evaluation of the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. precision and bias of a test method. Materials of known
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3975 − 93 (2008)
composition are required to identify biases. Consensus values collaborative test samples, hence homogeneity should be
obtained as the result of collaborative testing are not adequate attained, as far as possible.
to permit quantitative evaluation of biases, although they may
8. Preparation of Test Samples
show that such exist.
8.1 Authentic test samples may be procured from natural
6.2 Materials of adequate homogeneity but uncertain com-
sources or from suppliers of such materials. The specifications
position may be used to determine the precision of a given test
for such materials must be established on the basis of the
method. Both single-laboratory precision or between operator-
requirements for matrix composition, composition levels, and
laboratory precision can be evaluated.
sample size-homogeneity considerations of the particular test
6.3 Samples at only one compositional level can provide
method. Ordinarily, such materials will need to be disaggre-
information for performance statements for only the concen-
gated, sieved, and blended to obtain requisite homogeneity.
tration level of the test sample. Accordingly, other evidence is
Pulverizing samples is not recommended because the resulting
required to evaluate such factors as linearity and sensitivity.
changesinparticlesizedistributionessentiallyprecludetheuse
6.4 A series of samples, spanning the useful concentration
of the original size distribution or surface area for normalizing
rangeofthetestmethod,arerequiredtoevaluatetherelationof
analytical results. Much of the sample to sample concentration
the precision and bias to the concentration level measured.
variability, commonly observed in natural sediments, results
from differences in the particle size distribution. Samples may
7. Requirements for Test Samples
need preliminary drying (preferably freeze-drying) and the
7.1 The collaborative testing of proposed analytical proce-
dryingprocedurenecessarytoobtainconstantweightshouldbe
dures ideally requires samples identical to, or closely resem-
established. Practice D3976 provides guidance in this respect.
bling the materials for which the test method is designed to
8.2 Synthetic test samples are prepared to be equivalent to
analyze. Because this is not always possible, subrogate mate-
typical analytical samples as far as practicable. Materials
rials must often be used. Acceptable kinds of samples may be
required to prepare the test samples include those to simulate
classified as:
the matrix and the parameter(s) of the test method. The extent
7.1.1 Authentic—Samples identical in all respects to typical
to which these simulate a typical sample will determine the
test specimens.
reliability of its use as a test material. Homogeneity of mixing
7.1.2 Synthetic—Samples synthesized to be equivalent to
of synthetic samples must always be verified.
typical test samples. Spiked samples are a special class of
8.3 Spiked samples consist of those in which the substance
synthetic samples.
to be measured is added to an authentic or synthetic test
7.1.3 Simulative—Samples that do not resemble typical
sample,whichmayormaynotalreadycountmeasurablelevels
samples but that possess some parameter of concern of the test
of the constituent added. The spike may be a pure substance or
method.
a mixture or solution containing a known amount of the
7.2 As one proceeds down the list, the ability of the material
substance that is added quantitatively to the dried sediment.
to test the analytical method becomes more controversial.
The spiking procedure must be developed in accordance with
7.3 Test samples must have stable compositions during the
the requirements of the specific situation. Matrix consider-
test period.
ations are always of concern in that the added material may not
behave as it would in the case of natural occurrence. Thorough
7.4 Test samples must be sufficiently homogeneous to
mixing of the spiked sample is very important, although less
evaluate the test method. The degree of homogeneity is related
critical if the entire sample is used in the subsequent measure-
to the size of sample analyzed. Hence the minimum size of
ment.
sample meeting a specified homogeneity must be stated, and
this must be equal to or smaller than the size of sample
8.4 Samples that only possess some parameter of interest,
specified in the test method.
hence classified as “simulative,” should be used only when it is
not feasible to obtain “authentic” or “synthetic” samples. The
7.5 The sample must be available in sufficient quantity both
use of several simulative samples of differing matrices is
for the requirements of the collaborative test and to permit
recommended to minimize dependence of the test results on
further examination to resolve any operational questions.
matrix effects.
Preferably, an additional amount should be available for
possible examination by other techniques. A desirable objec-
9. Test Levels
tive would be the establishment of sample banks for future use
in: (a) testing r
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