ASTM D3975-93(1999)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 3975 – 93 (Reapproved 1999)
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 D 3975; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope recommended to evaluate the linearity of the test method.
Acceptable test materials, in order of preference are: three
1.1 This practice establishes uniform general procedures for
samples of different compositions; mixtures of two samples to
the development, (preparation) and use of samples in the
obtain the desired concentration levels; samples prepared by
collaborative testing of methods for chemical analysis of
dilution of a single sample.
sediments and similar materials.
4.2 In the absence of samples of known composition, the
1.2 The principles of this practice are applicable to aqueous
use of the spiking technique, in which standard additions of
samples with suitable technical modifications.
known constituents are made by established techniques, will be
1.3 This standard does not purport to address all of the
acceptable for evaluating the linearity and the bias of test
safety concerns, if any, associated with its use. It is the
methods. In such a case, the bias statement will consist of the
responsibility of the user of this standard to establish appro-
accuracy of recovery of the spike.
priate safety and health practices and determine the applica-
4.3 Comparison of a candidate test method with a standard
bility of regulatory limitations prior to use.
test method of known precision and bias will constitute an
2. Referenced Documents acceptable technique for evaluation of precision and bias. In
such comparative measurements, any convenient test samples
2.1 ASTM Standards:
may be used, provided they are shown to be stable during the
D 596 Practice for Reporting Results of Analysis of Water
time required to make the intercomparison, and that the
D 1129 Terminology Relating to Water
measurement sequences are chosen to minimize or eliminate
D 2777 Practice for Determination of Precision and Bias of
errors due to sample instability.
Applicable Methods of Committee D-19 on Water
D 3670 Practice for Determination of Precision and Bias of
5. Significance and Use
Methods of Committee D-22
5.1 The objective of this practice is to provide guidelines for
D 3976 Practice for Preparation of Sediment Samples for
the preparation of samples for use in collaborative tests, to
Chemical Analysis
evaluate methods during their development, and for the evalu-
E 691 Practice for Conducting an Interlaboratory Study to
ation of the precision and bias of proposed test methods.
Determine the Precision of a Test Method
5.2 Statements of the precision and bias are a mandatory
3. Terminology
part of ASTM test methods. Such an evaluation is necessary to
provide guidance to the user as to the reliability of measure-
3.1 Definitions—For definition of terms used in this prac-
ments that can be expected by its use. The statements are
tice, refer to Terminology D 1129.
developed on the basis of user experience (ordinarily collabo-
4. Summary of Practice
rative tests) with the test method.
5.3 The availability of test samples is a key requirement for
4.1 Test samples of adequately defined composition and
collaborative evaluation of test methods.
homogeneity are required for evaluating the precision and bias
of test methods. These samples should be typical in all respects
6. Rationale
to the sample for which the test method is applicable. Samples
6.1 The use of materials of demonstrated adequate homo-
with three levels of concentration of the measurand are
geneity and known composition enable evaluation of the
precision and bias of a test method. Materials of known
This practice is under the jurisdiction of ASTM Committee D-19 on Water and
composition are required to identify biases. Consensus values
is the direct responsibility of Subcommittee D19.07 on SedimentsCurrent edition
obtained as the result of collaborative testing are not adequate
approved Sept. 15, 1993. Published December 1993. Originally published as D 3975
– 80. Last previous edition D 3975 – 88.
to permit quantitative evaluation of biases, although they may
Annual Book of ASTM Standards, Vol 11.01.
show that such exist.
Annual Book of ASTM Standards, Vol 11.03.
4 6.2 Materials of adequate homogeneity but uncertain com-
Annual Book of ASTM Standards, Vol 11.02.
Annual Book of ASTM Standards, Vol 14.02. position may be used to determine the precision of a given test
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 3975
method. Both single-laboratory precision or between operator- method. Ordinarily, such materials will need to be disaggre-
laboratory precision can be evaluated. gated, sieved, and blended to obtain requisite homogeneity.
6.3 Samples at only one compositional level can provide Pulverizing samples is not recommended because the resulting
information for performance statements for only the concen- changes in particle size distribution essentially preclude the use
tration level of the test sample. Accordingly, other evidence is of the original size distribution or surface area for normalizing
required to evaluate such factors as linearity and sensitivity. analytical results. Much of the sample to sample concentration
6.4 A series of samples, spanning the useful concentration variability, commonly observed in natural sediments, results
range of the test method, are required to evaluate the relation of from differences in the particle size distribution. Samples may
the precision and bias to the concentration level measured. need preliminary drying (preferably freeze-drying) and the
drying procedure necessary to obtain constant weight should be
7. Requirements for Test Samples
established. Practice D 3976 provides guidance in this respect.
7.1 The collaborative testing of proposed analytical proce-
8.2 Synthetic test samples are prepared to be equivalent to
dures ideally requires samples identical to, or closely resem-
typical analytical samples as far as practicable. Materials
bling the materials for which the test method is designed to
required to prepare the test samples include those to simulate
analyze. Because this is not always possible, subrogate mate-
the matrix and the parameter(s) of the test method. The extent
rials must often be used. Acceptable kinds of samples may be
to which these simulate a typical sample will determine the
classified as:
reliability of its use as a test material. Homogeneity of mixing
7.1.1 Authentic—Samples identical in all respects to typical
of synthetic samples must always be verified.
test specimens.
8.3 Spiked samples consist of those in which the substance
7.1.2 Synthetic—Samples synthesized to be equivalent to
to be measured is added to an authentic or synthetic test
typical test samples. Spiked samples are a special class of
sample, which may or may not already count measurable levels
synthetic samples.
of the constituent added. The spike may be a pure substance or
7.1.3 Simulative—Samples that do not resemble typical
a mixture or solution containing a known amount of the
samples but that possess some parameter of concern of the test
substance that is added quantitatively to the dried sediment.
method.
The spiking procedure must be developed in accordance with
7.2 As one proceeds down the list, the ability of the material
the requirements of the specific situation. Matrix consider-
to test the analytical method becomes more controversial.
ations are always of concern in that the added material may not
7.3 Test samples must have stable compositions during the
behave as it would in the case of natural occurrence. Thorough
test period.
mixing of the spiked sample is very important, although less
7.4 Test samples must be sufficiently homogeneous to
critical if the entire sample is used in the subsequent measure-
evaluate the test method. The degree of homogeneity is related
ment.
to the size of sample analyzed. Hence the minimum size of
8.4 Samples that only possess some parameter of interest,
sample meeting a specified homogeneity must be stated, and
hence classified as “simulative,” should be used only when it is
this must be equal to or smaller than the size of sample
not feasible to obtain “authentic” or “synthetic” samples. The
specified in the test method.
use of several simulative samples of differing matrices is
7.5 The sample must be available in sufficient quantity both
recommended to minimize dependence of the test results on
for the requirements of the collaborative test and to permit
matrix effects.
further examination to resolve any operational questions.
Preferably, an additional amount should be available for
9. Test Levels
possible examination by other techniques. A desirable objec-
9.1 The test specimens used in a collaborative test should
tive would be the establishment of sample banks for future use
span the concentration range for which the test method is
in: (a) testing refinement of the method and (b) testing other
expected to be valid. Three levels—a high, intermediate, and
methodologies.
low level—are recommended. This requirement can be met by
7.6 The uncertainties in homogeneity or composition, or
the use of several test samples, by a dilution technique
both, of test samples should not exceed one third of the
involving a single
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