ASTM E2857-11(2021)e1

Standard Guide for Validating Analytical Methods

SIGNIFICANCE AND USE
4.1 Method validation is a process of demonstrating that the method meets the required performance capabilities. International standards such as ISO/IEC 17025, certifying bodies, and regulatory agencies require evidence that analytical methods are capable of producing valid results. This applies to laboratories using published standard test methods, modified standard test methods, and in-house test methods.  
4.2 Although a collaborative study is part of this guide, this guide may be used by a single laboratory for method validation when a formal collaboration study is not practical. This guide may also be applied before a full collaboration study to predict the reliability of the method.  
4.3 The use of multiple validation techniques described in this guide increases confidence in the validity or application of the method.  
4.4 It is beyond the scope of this guide to describe fully the fundamental considerations in Section 5. For a more descriptive definition of these concepts, refer to the International Union of Pure and Applied Chemistry (IUPAC) technical report, “Harmonized Guidelines for Single Laboratory Validation of Methods of Analysis,”5 the IUPAC Compendium of Analytical Nomenclature (Orange Book),6 and the Eurachem publication, The Fitness for Purpose of Analytical Methods, A Laboratory Guide to Method Validation and Related Topics.7
SCOPE
1.1 This guide describes procedures for the validation of chemical and spectrochemical analytical test methods that are used by a metals, ores, and related materials analysis laboratory.  
1.2 This guide may be applied to the validation of laboratory developed (in-house) methods, addition of analytes to an existing standard test method, variation or scope expansion of an existing standard method, or the use of new or different laboratory equipment.  
1.3 The suggested approaches in this guide may also be used to validate the implementation of standard test methods used routinely by laboratories of the mining, ore processing, and metals industry.  
1.4 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.

General Information

• Status: Historical
• Publication Date: 31-Jul-2021
• ICS: 71.040.40 - Chemical analysis
• ICS: 71.040.50 - Physicochemical methods of analysis
• Technical Committee: E01 - Analytical Chemistry for Metals, Ores, and Related Materials
• Drafting Committee: E01.22 - Laboratory Quality

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
´1
Designation: E2857 − 11 (Reapproved 2021)
Standard Guide for
Validating Analytical Methods
This standard is issued under the fixed designation E2857; 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.
ε NOTE—Editorial corrections were made throughout in August 2021.
1. Scope 2.2 ISO Standard:
ISO/IEC 17025 General requirements for the competence of
1.1 This guide describes procedures for the validation of
testing and calibration laboratories
chemical and spectrochemical analytical test methods that are
used by a metals, ores, and related materials analysis labora-
3. Terminology
tory.
3.1 Definitions—For definitions of terms used in this guide,
1.2 This guide may be applied to the validation of labora-
refer to Terminology E135.
tory developed (in-house) methods, addition of analytes to an
3.2 Definitions of Terms Specific to This Standard:
existing standard test method, variation or scope expansion of
3.2.1 validation (of an analytical method), n—confirmation,
an existing standard method, or the use of new or different
by the provision of objective evidence and examination, that a
laboratory equipment.
method meets performance requirements and is suitable for its
1.3 The suggested approaches in this guide may also be
intended use.
used to validate the implementation of standard test methods
used routinely by laboratories of the mining, ore processing,
4. Significance and Use
and metals industry.
4.1 Method validation is a process of demonstrating that the
1.4 This international standard was developed in accor-
method meets the required performance capabilities. Interna-
dance with internationally recognized principles on standard-
tional standards such as ISO/IEC 17025, certifying bodies, and
ization established in the Decision on Principles for the
regulatory agencies require evidence that analytical methods
Development of International Standards, Guides and Recom-
are capable of producing valid results. This applies to labora-
mendations issued by the World Trade Organization Technical
toriesusingpublishedstandardtestmethods,modifiedstandard
Barriers to Trade (TBT) Committee.
test methods, and in-house test methods.
2. Referenced Documents 4.2 Although a collaborative study is part of this guide, this
2 guidemaybeusedbyasinglelaboratoryformethodvalidation
2.1 ASTM Standards:
when a formal collaboration study is not practical. This guide
E135 Terminology Relating to Analytical Chemistry for
may also be applied before a full collaboration study to predict
Metals, Ores, and Related Materials
the reliability of the method.
E1601 Practice for Conducting an Interlaboratory Study to
4.3 The use of multiple validation techniques described in
Evaluate the Performance of an Analytical Method
E1763 Guide for Interpretation and Use of Results from this guide increases confidence in the validity or application of
the method.
Interlaboratory Testing of Chemical Analysis Methods
(Withdrawn 2015)
4.4 It is beyond the scope of this guide to describe fully the
fundamental considerations in Section 5. For a more descrip-
tive definition of these concepts, refer to the International
This guide is under the jurisdiction of ASTM Committee E01 on Analytical
Chemistry for Metals, Ores, and Related Materials and is the direct responsibility of Union of Pure and Applied Chemistry (IUPAC) technical
Subcommittee E01.22 on Laboratory Quality.
report, “Harmonized Guidelines for Single Laboratory Valida-
Current edition approved Aug. 1, 2021. Published August 2021. Originally
tion of Methods of Analysis,” the IUPAC Compendium of
approved in 2011. Last previous edition approved in 2016 as E2857 – 11(2016).
DOI: 10.1520/E2857-11R21E01.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
Standards volume information, refer to the standard’s Document Summary page on 4th Floor, New York, NY 10036, http://www.ansi.org.
the ASTM website. M. Thompson, S. Ellison, and R. Wood, “Harmonized Guidelines for Single-
The last approved version of this historical standard is referenced on Laboratory Validation of Methods of Analysis,” Pure Appl. Chem., Vol 71, No. 2,
www.astm.org. 2002, pp. 835-855. http://iupac.org/publications/pac
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
E2857 − 11 (2021)
Analytical Nomenclature (Orange Book), and the Eurachem 5.1.1.1 The most common estimators of precision are stan-
publication, The Fitness for Purpose of Analytical Methods, A darddeviation,relativestandarddeviation,andvariance.Equa-
Laboratory Guide to Method Validation and Related Topics. tions and examples are available in many texts on statistics.
5.1.1.2 Theconceptofmaintenanceoftherepeatabilityover
5. Fundamental Considerations
a period of time is known as statistical control. The laboratory
5.1 During the process of method validation, the user of an
can implement tools such as control charts to demonstrate
analyticalmethodshouldapplyanumberoffundamentaltenets
statistical control.
of analytical chemistry as they relate to the development and
5.1.2 Limit of Detection (L )—The limit of detection is
D
implementation of test methods. It is important to make the
defined as the lowest amount of analyte that can be distin-
distinction between the validation of a test method by a
guished from background by an analytical method. It is
standards-developing organization and the implementation of
important to demonstrate that the measurement process has the
that test method by a laboratory. Whether the test method was
capabilitytodetectasignificantlyloweramount(concentration
developed by a committee of experts or by one chemist in a
or mass fraction) of the analyte than the laboratory must
company laboratory, the laboratory shall implement the
quantify. For additional information, consult the IUPAC Or-
methodinthelaboratoryandshalldemonstratethatthemethod
ange Book and the Currie paper.
is being performed sufficiently well and that the results meet
5.1.3 Limit of Quantification (L )—The limit of quantifica-
Q
the goals for data quality.That is, they should ascertain that the
tion is defined as the amount of analyte above which the
measurement process provides sufficient levels of performance
estimated relative standard deviation (RSD) is ≤10 %. It is
fit for the purpose of testing the materials at hand. It is
important to demonstrate and document that the measurement
advisable to determine and document performance character-
process has the capability to quantify amounts less than or
istics of the method including repeatability precision, limit of
equal to those found in materials to which the test method is
detection,limitofquantification,andperhapsotherparameters.
applied.Foradditionalinformation,consulttheIUPACOrange
The laboratory is advised to evaluate the method for bias and
Book and the Currie paper.
for susceptibility to introduction of bias (namely, ruggedness).
5.1.4 Bias—Bias is the difference between the obtained
A number of important considerations are discussed in
result for a measurand and the true value of the measurand.An
5.1.1-5.1.7, but specific procedures for determination and
analytical method may be subject to a known amount of bias
calculation are beyond the scope of this guide.
that was estimated when the standard test method was devel-
oped and validated by a committee. In an analogous manner, a
NOTE 1—In the following discussion, the term measurement process
means the entire process by which a laboratory performs a test including
laboratory developing a new test method or implementing a
sample preparation, measurements, and calculation of results.
published standard test method shall perform tests to estimate
5.1.1 Precision—The first step in development and imple-
biasanddemonstratethemethod’sresistancetointroductionof
mentation of an analytical method is demonstration that
additional bias, that is, ruggedness. Documentation of this
measurements can be made with sufficient repeatability for the
performance enables the laboratory to elucidate the scope of
purpose of quantitative analysis. Precision is defined as the
the method and defend the results obtained using the method.
degree of agreement among a set of values. Precision under
NOTE 2—Accuracy is a concept related to both bias and precision. It is
repeatability conditions is measured by having a single analyst
the combination of knowledge of both the precision obtainable under
in a single laboratory use a single set of equipment to prepare
various conditions and the amount of bias inherent in a given result. The
and analyze portions of a homogeneous material. Precision concept of accuracy is often used in discussions of the fitness for purpose
and the reliability of results from a test method. In a published standard
under reproducibility conditions is measured by having a
test method, the statements of precision and bias taken together provide
number of different analysts at different laboratories prepare
the basis for judgments of the accuracy of the test method.
and analyze portions of a homogeneous material.Any number
5.1.5 Selectivity—Theselectivityofamethodisitsabilityto
of conditions intermediate between repeatability conditions
produce a result that is not subject to change in the presence of
and reproducibility conditions may be used if the data serves a
interfering constituents. The selectivity of a method can be
useful purpose.Agood example is having multiple analysts in
investigated by introducing or varying amounts of substances
a single laboratory perform the analyses, perhaps on multiple
and evaluating the results for changes. By understanding the
days.IntheterminologyofCommitteeE01,repeatabilityisthe
principal of measurement, the analyst may be able to define a
same as within-laboratory standard deviation, S , which is
r
short list of suspected interferences and, thereby, limit the
defined as the standard deviation of results collected on the
amount of effort needed to establish the significant interference
same material in the same laboratory on different days. In
effects.
contrast, reproducibility is synonymous with between-
5.1.6 Calibration Model—Relative methods require calibra-
laboratory standard deviation, S , which is defined as the
R
tion using measurements of suitable reference materials and
standard deviation of results obtained on the same material in
mathematicalfittingofthemeasuredresponsestoanalgorithm,
different laboratories.
that is, an equation thought to describe adequately the relation-
6 shipbetweentheamountofanalyteandthemeasuredresponse.
International Union of Pure and Applied Chemistry Compendium of Analytical
Nomenclature: Definitive Rules 1997, http://old.iupac.org/publications/analytical_
compendium/
7 8
EURACHEM Guide, The Fitness for Purpose of Analytical Methods, A L. A. Currie, “Nomenclature in Evaluation of Analytical Methods Including
Laboratory Guide to Method Validation and Related Topics, LGC, Teddington, DetectionandQuantificationCapabilities,” PureAppl. Chem.,Vol67,No.10,1995,
Middlesex, United Kingdom, 1998. www.eurachem.org pp. 1699-1723. http://iupac.org/publications/pac
´1
E2857 − 11 (2021)
Algorithms are almost always an approximation of the real 6.2 Analysis of Reference Materials:
world,andassuch,theirabilitytofitthedatahaslimitsthatcan
6.2.1 Select a number of reference materials such that the
be tested by a variety of means including, but not limited to,
analyte amount encompasses the intended scope of the analyti-
analyses of certified or other reference materials and statistical
cal method.
evaluation of confidence intervals bracketing the calibration
6.2.2 Analyze each reference material to determine the
curve and extrapolating performance predictions beyond the
analyteamountpresent.Replicatedeterminationsmaybemade
range of the calibrants.
if these data are to be used to estimate typical method
5.1.6.1 Working Range—The term working range is a name
precision. If possible, analyze reference materials that are
given to the concept of a portion of a calibration curve that
independent from the calibration. Record all results.
provides valid results as opposed to portions that are not fit for
6.2.3 Compare the reference material results to the values
purpose. The range in which the method is considered to be
assigned for the material by the developing organization.
valid can be characterized using a number of approaches. The
Assess the acceptability of the test method for generating data
preferred methods are those that use objective data for the
in accordance with the laboratory’s measurement quality ob-
purpose of illustrating under which circumstances a calibration
jectives.
model is fit for purpose.
6.2.4 The following protocol is one approach that has been
5.1.6.2 Calibration Performance—There are statistical
found to be an acceptable means of assessing the acceptability
methods for measuring how well the chosen calibration
of data obtained using this validation methodology.
algorithm, often a line, fits the data consisting of known
amountsofanalyteandmeasuredresponsesfromtheanalytical 6.2.4.1 Analyze each of the reference materials, for a
instrument for the calibrants. For every calibrant, one may minimum of triplicate determinations, in random order of
calculate the difference between known and calculated analyte amount. Record all results.
amounts. This information can be used to describe the perfor-
6.2.4.2 It is recommended that this determination be re-
manceofallorpartofthecalibration.Manythingscanbedone
peated over a specified number of days, under different
with the information, including calculating the standard devia-
calibration/setup conditions, unless thorough ruggedness test-
tion of the differences described in the previous section,
ing was performed during method development.
constructingconfidenceintervalsaroundallofpartoftherange
6.2.4.3 For each reference material used, calculate the mean
of amounts, plotting the difference as a function of the amount
of analyzed results, the standard deviation of the set of
to look for trends, and spotting any individual calibrant that
measured results, and an interval around the mean for a given
clearly performs more poorly than the rest. Documenting
confidence level.The confidence level should be chosen by the
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: E2857 − 11 (Reapproved 2016) E2857 − 11 (Reapproved 2021)
Standard Guide for
Validating Analytical Methods
This standard is issued under the fixed designation E2857; 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.
ε NOTE—Editorial corrections were made throughout in August 2021.
1. Scope
1.1 This guide describes procedures for the validation of chemical and spectrochemical analytical test methods of analysis that are
used by a metals, ores, and related materials analysis laboratory.
1.2 This guide may be applied to the validation of laboratory developed (in-house) methods, addition of analytes to an existing
standard test method, variation or scope expansion of an existing standard method, or the use of new or different laboratory
equipment.
1.3 This The suggested approaches in this guide may also be used to validate the implementation of standard test methods used
routinely by laboratories of the mining, ore processing, and metals industry.
1.4 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.
2. Referenced Documents
2.1 ASTM Standards:
E135 Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
E1601 Practice for Conducting an Interlaboratory Study to Evaluate the Performance of an Analytical Method
E1763 Guide for Interpretation and Use of Results from Interlaboratory Testing of Chemical Analysis Methods (Withdrawn
2015)
2.2 ISO Standard:
ISO/IEC 17025 General requirements for the competence of testing and calibration laboratories
3. Terminology
3.1 Definitions—For definitions of terms used in this guide, refer to Terminology E135.
3.2 Definitions of Terms Specific to This Standard:
This guide is under the jurisdiction of ASTM Committee E01 on Analytical Chemistry for Metals, Ores, and Related Materials and is the direct responsibility of
Subcommittee E01.22 on Laboratory Quality.
Current edition approved Oct. 1, 2016Aug. 1, 2021. Published October 2016August 2021. Originally approved in 2011. Last previous edition approved in 20112016 as
E2857E2857 – 11–11.(2016). DOI: 10.1520/E2857–11R16.10.1520/E2857-11R21E01.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
E2857 − 11 (2021)
3.2.1 validation (of an analytical method), n—confirmation, by the provision of objective evidence and examination, that a method
meets performance requirements and is suitable for its intended use.
4. Significance and Use
4.1 Method validation is a process of demonstrating that the method meets the required performance capabilities. International
standards such as ISO/IEC 17025, certifying bodies, and regulatory agencies require evidence that analytical methods are capable
of producing valid results. This applies to laboratories using published standard test methods, modified standard test methods, and
in-house test methods.
4.2 Although a collaborative study is part of this guide, this guide may be used by a single laboratory for method validation when
a formal collaboration study is not practical. This guide may also be applied before a full collaboration study to predict the
reliability of the method.
4.3 The use of multiple validation techniques described in this guide increases confidence in the validity or application of the
method.
4.4 It is beyond the scope of this guide to describe fully the fundamental considerations in Section 5. For a more descriptive
definition of these concepts, refer to the International Union of Pure and Applied Chemistry (IUPAC) technical report,
“Harmonized Guidelines for Single Laboratory Validation of Methods of Analysis,” the IUPAC Compendium of Analytical
Nomenclature (Orange Book), and the Eurachem publication, The Fitness for Purpose of Analytical Methods, A Laboratory Guide
to Method Validation and Related Topics.
5. Fundamental Considerations
5.1 During the process of method validation, the user of an analytical method should apply a number of fundamental tenets of
analytical chemistry as they relate to the development and implementation of test methods. It is important to make the distinction
between the validation of a test method by a standards-developing organization and the implementation of that test method by a
laboratory. Whether the test method was developed by a committee of experts or by one chemist in a company laboratory, the
laboratory shall implement the method in the laboratory and shall demonstrate that the method is being performed sufficiently well
and that the results meet the goals for data quality. That is, they should ascertain that the measurement process provides sufficient
levels of performance fit for the purpose of testing the materials at hand. It is advisable to determine and document performance
characteristics of the method including repeatability precision, limit of detection, limit of quantification, and perhaps other
parameters. The laboratory is advised to evaluate the method for bias and for susceptibility to introduction of bias (namely,
ruggedness). A number of important considerations are discussed in 5.1.1-5.1.7, but specific procedures for determination and
calculation are beyond the scope of this guide.
NOTE 1—In the following discussion, the term measurement process is taken to mean means the entire process by which a laboratory performs a test
including sample preparation, measurements, and calculation of results.
5.1.1 Precision—The first step in development and implementation of an analytical method is demonstration that measurements
can be made with sufficient repeatability for the purpose of quantitative analysis. Precision is defined as the degree of agreement
among a set of values. Precision under repeatability conditions is measured by having a single analyst in a single laboratory use
a single set of equipment to prepare and analyze portions of a homogeneous material. Precision under reproducibility conditions
is measured by having a number of different analysts at different laboratories prepare and analyze portions of a homogeneous
material. Any number of conditions intermediate between repeatability conditions and reproducibility conditions may be used if
the data serves a useful purpose. A good example is having multiple analysts in a single laboratory perform the analyses, perhaps
on multiple days. In the terminology of Committee E01, repeatability is synonymous with the same as within-laboratory standard
deviation, S , which is defined as the standard deviation of results collected on the same material in the same laboratory on different
r
M. Thompson, S. Ellison, and R. Wood, “Harmonized Guidelines for Single-Laboratory Validation of Methods of Analysis,” Pure Appl. Chem., Vol 71, No. 2, 2002, pp.
835-855. http://iupac.org/publications/pac
International Union of Pure and Applied Chemistry Compendium of Analytical Nomenclature: Definitive Rules 1997, http://old.iupac.org/publications/analytical_
compendium/
EURACHEM Guide, The Fitness for Purpose of Analytical Methods, A Laboratory Guide to Method Validation and Related Topics, LGC, Teddington, Middlesex, United
Kingdom, 1998. www.eurachem.org
´1
E2857 − 11 (2021)
days. In contrast, reproducibility is synonymous with between-laboratory standard deviation, S , which is defined as the standard
R
deviation of results obtained on the same material in different laboratories.
5.1.1.1 The most common estimators of precision are standard deviation, relative standard deviation, and variance. Equations and
examples are available in many texts on statistics.
5.1.1.2 The concept of maintenance of the repeatability over a period of time is known as statistical control. The laboratory can
implement tools such as control charts to demonstrate statistical control.
5.1.2 Limit of Detection (L )—The detection limit of detection is defined as the lowest amount of analyte that can be distinguished
D
from background by an analytical method. It is important to demonstrate that the measurement process has the capability to detect
a significantly lower amount (concentration or mass fraction) of the analyte than the laboratory must quantify. For additional
information, consult the IUPAC Orange Book and the Currie paper.
5.1.3 Limit of Quantification (L )—The limit of quantification is defined as the amount of analyte above which the estimated
Q
relative standard deviation (RSD) is ≤10 %. It is important to demonstrate and document that the measurement process has the
capability to quantify amounts less than or equal to those found in materials to which the test method is applied. For additional
information, consult the IUPAC Orange Book and the Currie paper.
5.1.4 Bias—Bias is the difference between the obtained result for a measurand and the true value of the measurand. An analytical
method may be subject to a known amount of bias that was estimated when the standard test method was developed and validated
by a committee. In an analogous manner, a laboratory developing a new test method or implementing a published standard test
method shall perform tests to estimate bias and demonstrate the method’s resistance to introduction of additional bias, that is,
ruggedness. Documentation of this performance enables the laboratory to elucidate the scope of the method and defend the results
obtained using the method.
NOTE 2—Accuracy is a concept related to both bias and precision. It is the combination of knowledge of both the precision obtainable under various
conditions and the amount of bias inherent in a given result. The concept of accuracy is often used in discussions of the fitness for purpose and the
reliability of results from a test method. In a published standard test method, the statements of precision and bias taken together provide the basis for
judgments of the accuracy of the test method.
5.1.5 Selectivity—The selectivity of a method is its ability to produce a result that is not subject to change in the presence of
interfering constituents. The selectivity of a method can be investigated by introducing or varying amounts of substances and
evaluating the results for changes. By understanding the principal of measurement, the analyst may be able to define a short list
of suspected interferences and, thereby, limit the amount of effort needed to establish the significant interference effects.
5.1.6 Calibration Model—Relative methods require calibration using measurements of suitable reference materials and
mathematical fitting of the measured responses to an algorithm, that is, an equation thought to describe adequately the relationship
between the amount of analyte and the measured response. Algorithms are almost always an approximation of the real world, and
as such, their ability to fit the data has limits that can be tested by a variety of means including, but not limited to, analyses of
certified or other reference materials and statistical evaluation of confidence intervals bracketing the calibration curve and
extrapolating performance predictions beyond the range of the calibrants.
5.1.6.1 Working Range—The term working range is a name given to the concept of a portion of a calibration curve that provides
valid results as opposed to portions that are not fit for purpose. The range in which the method is considered to be valid can be
characterized using a number of approaches. The preferred methods are those that use objective data for the purpose of illustrating
under which circumstances a calibration model is fit for purpose.
5.1.6.2 Calibration Performance—There are statistical methods for measuring how well the chosen calibration algorithm, often
a line, fits the data consisting of known amounts of analyte and measured responses from the analytical instrument for the
calibrants. For every calibrant, one may calculate the difference between known and calculated amounts. This information can be
used to describe the performance of all or part of the calibration. One can do any of a number of things Many things can be done
with the information, including calculating the standard deviation of the differences described above, in the previous section,
constructing confidence intervals around all of part of the range of amounts, plotting the difference as a function of the amount
to look for trends, and spotting any individual calibrant that clearly performs more poorly than the rest. Documenting behaviors
like these, seeking the causes, and taking corrective actions are suggested means to validate a test method.
L. A. Currie, “Nomenclature in Evaluation of Analytical Methods Including Detection and Quantification Capabilities,” Pure Appl. Chem., Vol 67, No. 10, 1995, pp.
1699-1723. http://iupac.org/publications/pac
´1
E2857 − 11 (2021)
NOTE 3—The applications of statistical tools, for example, confidence intervals around a calibration, need not be restricted to the region bounded by the
lowest and highest calibrants or the lowest and highest validation reference materials measured using the method and a particular calibration. These tools
can be extrapolated and still provide valid estimates of method performance.
5.1.7 Ruggedness—Considered in its classical sense, ruggedness of an analytical method is the resistance of the results to change
caused by variations in the operational aspects of a test method. Operations characteristics may include substitution of machines
used to prepare a specimen, substitution of s
...