ASTM D3975-93(2014)
(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
5.1 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.
5.2 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.
5.3 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 2014)
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 Jan. 1, 2014. Published February 2014. Originally
approved in 1980. Last previous edition approved in 2008 as D3975 – 93 (2008).
6. Rationale
DOI: 10.1520/D3975-93R14.
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 (2014)
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
information for performance statements for only the concen-
disaggregated, sieved, and blended to obtain requisite homo-
tration level of the test sample. Accordingly, other evidence is
geneity. Pulverizing samples is not recommended because the
required to evaluate such factors as linearity and sensitivity.
resulting changes in particle size distribution essentially pre-
clude the use of the original size distribution or surface area for
6.4 A series of samples, spanning the useful concentration
normalizing analytical results. Much of the sample to sample
rangeofthetestmethod,arerequiredtoevaluatetherelationof
concentration variability, commonly observed in natural
the precision and bias to the concentration level measured.
sediments, results from differences in the particle size distri-
7. Requirements for Test Samples bution. Samples may need preliminary drying (preferably
freeze-drying) and the drying procedure necessary to obtain
7.1 The collaborative testing of proposed analytical proce-
constant weight should be established. Practice D3976 pro-
dures ideally requires samples identical to, or closely resem-
vides guidance in this respect.
bling the materials for which the test method is designed to
analyze. Because this is not always possible, subrogate mate- 8.2 Synthetic test samples are prepared to be equivalent to
rials must often be used. Acceptable kinds of samples may be typical analytical samples as far as practicable. Materials
classified as:
required to prepare the test samples include those to simulate
7.1.1 Authentic—Samples identical in all respects to typical the matrix and the parameter(s) of the test method. The extent
test specimens.
to which these simulate a typical sample will determine the
7.1.2 Synthetic—Samples synthesized to be equivalent to reliability of its use as a test material. Homogeneity of mixing
typical test samples. Spiked samples are a special class of
of synthetic samples must always be verified.
synthetic samples.
8.3 Spiked samples consist of those in which the substance
7.1.3 Simulative—Samples that do not resemble typical
to be measured is added to an authentic or synthetic test
samples but that possess some parameter of concern of the test
sample,whichmayormaynotalreadycountmeasurablelevels
method.
of the constituent added. The spike may be a pure substance or
7.2 As one proceeds down the list, the ability of the material a mixture or solution containing a known amount of the
to test the analytical method becomes more controversial. substance that is added quantitatively to the dried sediment.
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
7.4 Test samples must be sufficiently homogeneous to
behave as it would in the case of natural occurrence. Thorough
evaluate the test method. The degree of homogeneity is related
mixing of the spiked sample is very important, although less
to the size of sample analyzed. Hence the minimum size of
critical if the entire sample is used in the subsequent measure-
sample meeting a specified homogeneity must be stated, and
ment.
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
7.5 The sample must be available in sufficient quantity both
not feasible to obtain “authentic” or “synthetic” samples. The
for the requirements of the collaborative test and to permit
use of several simulative samples of differing matrices is
further examination to resolve any operational questions.
recommended to minimize dependence of the test results on
Preferably, an additional amount should be available for
matrix effects.
possible examination by other techniques. A desirable objec-
9. Test Levels
tive would be the establishment of sample banks for future use
in: (1) testing refinement of
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