ASTM D3975-93(2019)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D3975 − 93 (Reapproved 2019)
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 3. Terminology
1.1 This practice establishes uniform general procedures for
3.1 Definitions:
the development (preparation) and use of samples in the
3.1.1 For definitions of terms used in this standard, refer to
collaborative testing of methods for chemical analysis of
Terminology D1129.
sediments and similar materials.
4. Summary of Practice
1.2 The principles of this practice are applicable to aqueous
samples with suitable technical modifications.
4.1 Test samples of adequately defined composition and
1.3 This standard does not purport to address all of the homogeneity are required for evaluating the precision and bias
safety concerns, if any, associated with its use. It is the of test methods.These samples should be typical in all respects
responsibility of the user of this standard to establish appro- to the sample for which the test method is applicable. Samples
priate safety, health, and environmental practices and deter- with three levels of concentration of the measurand are
mine the applicability of regulatory limitations prior to use. recommended to evaluate the linearity of the test method.
1.4 This international standard was developed in accor- Acceptable test materials, in order of preference are: three
samples of different compositions; mixtures of two samples to
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the obtain the desired concentration levels; samples prepared by
dilution of a single sample.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
4.2 In the absence of samples of known composition, the
Barriers to Trade (TBT) Committee.
use of the spiking technique, in which standard additions of
knownconstituentsaremadebyestablishedtechniques,willbe
2. Referenced Documents
acceptable for evaluating the linearity and the bias of test
2.1 ASTM Standards: methods. In such a case, the bias statement will consist of the
D596 Guide for Reporting Results of Analysis of Water accuracy of recovery of the spike.
D1129 Terminology Relating to Water
4.3 Comparison of a candidate test method with a standard
D2777 Practice for Determination of Precision and Bias of
test method of known precision and bias will constitute an
Applicable Test Methods of Committee D19 on Water
acceptable technique for evaluation of precision and bias. In
D3670 Guide for Determination of Precision and Bias of
such comparative measurements, any convenient test samples
Methods of Committee D22
may be used, provided they are shown to be stable during the
D3976 Practice for Preparation of Sediment Samples for
time required to make the intercomparison, and that the
Chemical Analysis
measurement sequences are chosen to minimize or eliminate
E691 Practice for Conducting an Interlaboratory Study to
errors due to sample instability.
Determine the Precision of a Test Method
5. Significance and Use
5.1 Theobjectiveofthispracticeistoprovideguidelinesfor
This practice is under the jurisdiction of ASTM Committee D19 on Water and
the preparation of samples for use in collaborative tests, to
is the direct responsibility of Subcommittee D19.07 on Sediments, Geomorphology,
and Open-Channel Flow.
evaluate methods during their development, and for the evalu-
Current edition approved Nov. 1, 2019. Published December 2019. Originally
ation of the precision and bias of proposed test methods.
approved in 1980. Last previous edition approved in 2014 as D3975 – 93 (2014).
DOI: 10.1520/D3975-93R19.
5.2 Statements of the precision and bias are a mandatory
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
part ofASTM test methods. Such an evaluation is necessary to
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
provide guidance to the user as to the reliability of measure-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. ments that can be expected by its use. The statements are
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3975 − 93 (2019)
developed on the basis of user experience (ordinarily collab- tive would be the establishment of sample banks for future use
orative tests) with the test method. in: (1) testing refinement of the method and (2) testing other
methodologies.
5.3 The availability of test samples is a key requirement for
collaborative evaluation of test methods. 7.6 The uncertainties in homogeneity or composition, or
both, of test samples should not exceed one third of the
6. Rationale measurement uncertainties they are expected to evaluate.
When this specification is met, sample uncertainties make a
6.1 The use of materials of demonstrated adequate homo-
negligible contribution to the variance of the test results.While
geneity and known composition enable evaluation of the
replicate samples may be used in practical analysis to average
precision and bias of a test method. Materials of known
out sample variations, this is usually not feasible in the case of
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
show that such exist.
8. Preparation of Test Samples
6.2 Materials of adequate homogeneity but uncertain com-
8.1 Authentic test samples may be procured from natural
position may be used to determine the precision of a given test
sources or from suppliers of such materials. The specifications
method. Both single-laboratory precision or between operator-
for such materials must be established on the basis of the
laboratory precision can be evaluated.
requirements for matrix composition, composition levels, and
6.3 Samples at only one compositional level can provide
sample size-homogeneity considerations of the particular test
information for performance statements for only the concen-
method. Ordinarily, such materials will need to be
tration level of the test sample. Accordingly, other evidence is
disaggregated, sieved, and blended to obtain requisite homo-
required to evaluate such factors as linearity and sensitivity.
geneity. Pulverizing samples is not recommended because the
resulting changes in particle size distribution essentially pre-
6.4 A series of samples, spanning the useful concentration
clude the use of the original size distribution or surface area for
rangeofthetestmethod,arerequiredtoevaluatetherelationof
normalizing analytical results. Much of the sample to sample
the precision and bias to the concentration level measured.
concentration variability, commonly observed in natural
sediments, results from differences in the particle size distri-
7. Requirements for Test Samples
bution. Samples may need preliminary drying (preferably
7.1 The collaborative testing of proposed analytical proce-
freeze-drying) and the drying procedure necessary to obtain
dures ideally requires samples identical to, or closely resem-
constant weight should be established. Practice D3976 pro-
bling the materials for which the test method is designed to
vides guidance in this respect.
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.
7.1.3 Simulative—Samples that do not resemble typical
8.3 Spiked samples consist of those in which the substance
samples but that possess some parameter of concern of the test
to be measured is added to an authentic or synthetic test
method.
sample,whichmayormaynotalreadycountmeasurablelevels
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.
7.3 Test samples must have stable compositions during the
The spiking procedure must be developed in accordance with
test period.
the requirements of the specific situation. Matrix consider-
7.4 Test samples must be sufficiently homogeneous to ations are always of concern in that the added material may not
evaluate the test method. The degree of homogeneity is related behave as it would in the case of natural occurrence. Thorough
to the size of sample analyzed. Hence the minimum size of mixing of the spiked sample is very important, although less
sample meeting a specified homogeneity must be stated, and
critical if the entire sample is used in the subsequent m
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