ASTM D3975-93(2003)
(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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Designation:D 3975–93 (Reapproved 2003)
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 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
2. Referenced Documents accuracy of recovery of the spike.
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
D 596 Practice for Reporting Results of Analysis of Water
acceptable technique for evaluation of precision and bias. In
D 1129 Terminology Relating to Water
such comparative measurements, any convenient test samples
D 2777 Practice for Determination of Precision and Bias of
may be used, provided they are shown to be stable during the
Applicable Methods of Committee D19 on Water
time required to make the intercomparison, and that the
D 3670 Practice for Determination of Precision and Bias of
measurement sequences are chosen to minimize or eliminate
Methods of Committee D22
errors due to sample instability.
D 3976 Practice for Preparation of Sediment Samples for
Chemical Analysis
5. Significance and Use
E 691 Practice for Conducting an Interlaboratory Study to
5.1 Theobjectiveofthispracticeistoprovideguidelinesfor
Determine the Precision of a Test Method
the preparation of samples for use in collaborative tests, to
3. Terminology
evaluate methods during their development, and for the evalu-
ation of the precision and bias of proposed test methods.
3.1 Definitions—For definition of terms used in this prac-
5.2 Statements of the precision and bias are a mandatory
tice, refer to Terminology D 1129.
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-
ments that can be expected by its use. The statements are
4.1 Test samples of adequately defined composition and
developed on the basis of user experience (ordinarily collabo-
homogeneity are required for evaluating the precision and bias
rative tests) with the test method.
5.3 The availability of test samples is a key requirement for
This practice is under the jurisdiction of ASTM Committee D19 on Water and
collaborative evaluation of test methods.
is the direct responsibility of Subcommittee D19.07 on Sediments, Geomorphology,
and Open-Channel Flow.
6. Rationale
Current edition approved June 10, 2003. Published August 2003. Originally
approved in 1980. Last previous edition approved in 1999 as D 3975 – 93(1999).
6.1 The use of materials of demonstrated adequate homo-
Annual Book of ASTM Standards, Vol 11.01.
geneity and known composition enable evaluation of the
Annual Book of ASTM Standards, Vol 11.03.
precision and bias of a test method. Materials of known
Annual Book of ASTM Standards, Vol 11.02.
Annual Book of ASTM Standards, Vol 14.02. composition are required to identify biases. Consensus values
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 3975–93 (2003)
obtained as the result of collaborative testing are not adequate 8. Preparation of Test Samples
to permit quantitative evaluation of biases, although they may
8.1 Authentic test samples may be procured from natural
show that such exist.
sources or from suppliers of such materials. The specifications
6.2 Materials of adequate homogeneity but uncertain com-
for such materials must be established on the basis of the
position may be used to determine the precision of a given test
requirements for matrix composition, composition levels, and
method. Both single-laboratory precision or between operator-
sample size-homogeneity considerations of the particular test
laboratory precision can be evaluated.
method. Ordinarily, such materials will need to be disaggre-
6.3 Samples at only one compositional level can provide
gated, sieved, and blended to obtain requisite homogeneity.
information for performance statements for only the concen-
Pulverizing samples is not recommended because the resulting
tration level of the test sample. Accordingly, other evidence is
changesinparticlesizedistributionessentiallyprecludetheuse
required to evaluate such factors as linearity and sensitivity.
of the original size distribution or surface area for normalizing
6.4 A series of samples, spanning the useful concentration
analytical results. Much of the sample to sample concentration
rangeofthetestmethod,arerequiredtoevaluatetherelationof
variability, commonly observed in natural sediments, results
the precision and bias to the concentration level measured.
from differences in the particle size distribution. Samples may
need preliminary drying (preferably freeze-drying) and the
7. Requirements for Test Samples
dryingprocedurenecessarytoobtainconstantweightshouldbe
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-
bling the materials for which the test method is designed to typical analytical samples as far as practicable. Materials
required to prepare the test samples include those to simulate
analyze. Because this is not always possible, subrogate mate-
rials must often be used. Acceptable kinds of samples may be the matrix and the parameter(s) of the test method. The extent
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
typical test samples. Spiked samples are a special class of to be measured is added to an authentic or synthetic test
sample,whichmayormaynotalreadycountmeasurablelevels
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-
tive would be the establishment of sample banks for future use 9.1 The test specimens used in a collaborative test should
span the concentratio
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