ASTM E882-10(2016)e1
(Guide)Standard Guide for Accountability and Quality Control in the Chemical Analysis Laboratory
Standard Guide for Accountability and Quality Control in the Chemical Analysis Laboratory
SIGNIFICANCE AND USE
4.1 An accountability and quality control system is established by laboratory management to improve the quality of its results. It provides documented records which serve to assure users of the laboratory's services that a specified level of precision is achieved in the routine performance of its measurements and that the data reported were obtained from the samples submitted. The system also provides for: early warning to analysts when methods or equipment begin to develop a bias or show deterioration of precision; the protection and retrievability of data (results); traceability and control of samples as they are processed through the laboratory; good communication of sample information between submitters, analysts, and supervision; and information on sample processing history. This guide describes such a system. Other accountability and quality control programs can be developed. Such programs can be equivalent to the program in this guide if they provide all of the benefits mentioned above.
SCOPE
1.1 This guide covers the essential aspects of an accountability and quality control program for a chemical analysis laboratory. The reasons for establishing and operating such a program are discussed.
1.2 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
Relations
Standards Content (Sample)
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.
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Designation: E882 − 10 (Reapproved 2016)
Standard Guide for
Accountability and Quality Control in the Chemical Analysis
Laboratory
This standard is issued under the fixed designation E882; 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—Section 6.5.4 was corrected editorially in October 2017.
1. Scope 4. Significance and Use
1.1 This guide covers the essential aspects of an account-
4.1 An accountability and quality control system is estab-
ability and quality control program for a chemical analysis
lished by laboratory management to improve the quality of its
laboratory. The reasons for establishing and operating such a
results. It provides documented records which serve to assure
program are discussed.
users of the laboratory’s services that a specified level of
1.2 This international standard was developed in accor- precision is achieved in the routine performance of its mea-
surements and that the data reported were obtained from the
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the samples submitted. The system also provides for: early warn-
Development of International Standards, Guides and Recom- ing to analysts when methods or equipment begin to develop a
mendations issued by the World Trade Organization Technical bias or show deterioration of precision; the protection and
retrievability of data (results); traceability and control of
Barriers to Trade (TBT) Committee.
samples as they are processed through the laboratory; good
2. Referenced Documents
communication of sample information between submitters,
analysts, and supervision; and information on sample process-
2.1 ASTM Standards:
ing history.This guide describes such a system. Other account-
E135 Terminology Relating to Analytical Chemistry for
ability and quality control programs can be developed. Such
Metals, Ores, and Related Materials
programs can be equivalent to the program in this guide if they
E1329 Practice for Verification and Use of Control Charts in
provide all of the benefits mentioned above.
Spectrochemical Analysis
2.2 ASTM Manual:
5. Accountability
MNL 7A Manual on Presentation of Data and Control Chart
Analysis
5.1 Accountability means assurance that the results reported
2.3 ASQC Document:
refer directly to the samples submitted.
ASQC Standard A1 Definitions, Symbols, Formulas, and
5.2 Prior to submitting samples to the laboratory, the pro-
Tables for Control Charts
spective user should consult with laboratory personnel con-
cerning his needs and the capability of the laboratory to satisfy
3. Terminology
them. It is the responsibility of the originator of the samples to
3.1 Definitions—For definitions of terms used in this guide,
select and identify proper samples for submission to the
refer to Terminology E135.
laboratory, to decide what information is required, and, after
consulting with laboratory personnel, to submit the samples in
suitable containers, properly labeled, and accompanied by
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
written instructions identifying the samples, their nature, and
Subcommittee E01.22 on Laboratory Quality.
the information sought through chemical analysis. This should
Current edition approved Dec. 1, 2016. Published December 2016. Originally
be done formally, using a well-defined document for informa-
approved in 1982. Last previous edition approved in 2016 as E882 – 10 (2016).
DOI: 10.1520/E0882-10R16E01. tion transfer to initiate work in the laboratory.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.3 Laboratory management establishes a written account-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
ability system to be used throughout the laboratory at all times.
the ASTM website.
This implies traceability and documentation of all reported
ASTM Manual Series, ASTM, 7th Edition, 2002.
results through the laboratory back to the submitted sample.
Available from American Society for Quality (ASQ), 600 N. Plankinton Ave.,
Milwaukee, WI 53203, http://www.asq.org. This system should have the following general characteristics:
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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E882 − 10 (2016)
5.3.1 Each testing request submitted by a user of the customer specifications may dictate the records that must be
laboratory’s services is assigned an internal laboratory identi- retained and the retention times for both analytical records and
laboratory samples.
fication number (ID), which is used to correlate all samples,
work, time, and cost accounting, consultation, and reports and
6. Quality Control
other paperwork associated with that request. The final report
that is returned to the originator will always bear the number
6.1 Quality control of analytical methods provides the
(ID) for future reference. Moreover, it is convenient for
information needed to ensure that procedures, equipment, and
laboratory data to be filed according to sequential ID numbers.
personnel are performing at the levels of precision and accu-
For example, “86/0428” might identify the associated work as
racy required by the intended use of the data.
the 428th request submitted in the year 1986.The Data Record
6.2 General Characteristics—The following factors have
shouldprovidealldatageneratedduringtheanalyses,namesof
been found helpful in maximizing the effectiveness and mini-
persons performing the analyses, dates the analyses were
mizing the cost of quality control procedures:
performed, and any unusual occurrences that happened during
6.2.1 Involvetheoperatorsoranalystswhoactuallyperform
the analyses. Accountability for production control samples is
the work to the greatest possible extent.
normally maintained separately from the other testing records
6.2.2 Use the simplest, most direct statistical procedures
because results from production control samples are usually
that will provide the necessary degree of control. This means
reported on routine report forms, the samples being identified
thatgraphicalorsimplifiedarithmeticproceduresarepreferred.
with the day, shift, run, or lot from which they were taken. 6.2.3 Perform the quality control measurements as early in
the measurement process as possible. This prevents waste of
5.3.2 Each sample, specimen, sample site, or other unique
analytical effort if the method is not initially in control.
pieceofmaterialorcontaineridentifiedasaseparatesampleby
However, when a prolonged series of measurements is made, it
the originator should be assigned a sequential item number
is also necessary to verify that the method remains in control
(NN) for internal laboratory use. As soon as the samples are
throughout the run.
accepted by the laboratory, laboratory personnel will mark
6.2.4 Provide specific action limits and describe exactly
each sample or sample container with its own laboratory
what must be done when these limits are exceeded.
sample number (ID-NN) in such manner that the label is not
6.2.5 For each method (for each sample type), choose a
likely to become separated from its sample or rendered
control material that is known to be stable, homogeneous and
unreadable during its residence in the laboratory. For example,
has measured values within the range of interest.Any inhomo-
the fifth sample on the above-mentioned request might be
geneity in the control sample will add to the variance of the
identified as “86/0428-05.”
results. Any increase in variability that is not related to the
5.3.3 All laboratory work records, intermediate sample
measurement process will reduce the sensitivity of the quality
containers, data, and reports for a specific sample will be
control procedure to detect changes in the measurement
identified by the same laboratory identification and item
process. Where possible, the control material should be similar
number to avoid any opportunity for samples or data to be lost
to the samples to be analyzed. Obtain as large an amount of
or intermixed within or between requests.
control material as can be prepared in a homogeneous state
because considerable effort is required to prepare a new
5.3.4 The first and last steps in the accountability procedure
control.Alwaysprepareanewcontrolmaterialwellinadvance
are functions of technical supervision. Before any work is
of exhausting the old one so that the new supply is ready when
performed, the compatibility of the work requested with the
needed.Insituationswheresatisfactorycontrolmaterialcannot
physical condition of the samples and the capabilities of the
be obtained, alternative techniques (such as, retest by a senior
laboratory must be verified.When the analysts have completed
analyst) may be substituted for the control material approach.
their work, the results must be reviewed to be certain that all
6.2.6 Give analysts specific instructions concerning their
information requested has been determined and that the work
response to an out-of-control condition. Supervision may
has been performed with the required care and precision. In
decide that, if the analyst can correct the problem so that the
this latter regard, quality control procedures prove invaluable
control sample results are again within limits, the process may
both to the analysts performing the work and the reviewing
continue without immediate contact with the supervisor. In
supervisor. The supervisor also verifies that the results are
other situations, the supervisor may need to become involved
calculated in units that are most meaningful to the submitter
witheachout-of-controlincident.Ineithercase,adjustmentsto
and that the units and basis on which the results are calculated
the process should be recorded to explain each shift in the
are clearly stated.
control measurements.
5.3.5 Except for the most routine work, the original ana-
6.2.7 Provide for a periodic in-depth review by supervision
lyst’s data book, a serial listing of laboratory identification
and management of the overall effectiveness of the laboratory
numbers and descriptions, and a copy of each job report are
quality control system. Operating experience may indicate that
retained in the laboratory’s records for the periods of time
methodsshouldbeaddedto,ordroppedfromtheprogram,that
established by laboratory policy. Intermediate calculations and
the frequency of specific control samples should be increased
samples are normally discarded after the submitter has had a
or decreased, or that a different strategy might be more
reasonable opportunity to submit questions concerning the
appropriate for control of a specific method. The interval for
results and request return of his samples. In some cases, such reviews should be determined by the uniformity of the
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E882 − 10 (2016)
processes that generate the samples. Any anticipated or ob- made during a period that samples are being analyzed (such
served change in the character of the samples being analyzed period could, for example, be a shift or a day in a continuous
should initiate at least a cursory review of the control proce-
analysis process). Each individual value is plotted on the
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dures for the methods that apply to those samples.
X-chart as the measurement is completed. Their average value
¯
and range are plotted on the X- and R-charts. The additional
6.3 Laboratory Quality Control Strategies—Control chart
effort to prepare and maintain both types of control charts may
methods are suitable for laboratory quality control programs.
be justified in situations where erroneous assays would cause
The choice of which control strategy to use depends on
large economic losses. Other control chart techniques that may
circumstances: the type of instrument or laboratory procedure,
be appropriate for special circumstances may be found in the
the number of samples and frequency of the analyses, and the
ASQC Standard A1 document.
closeness of control required. The following are appropriate:
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6.3.1 The X- and R-chart method is most frequently used.
6.3.4 Comparisonwithcertifiedreferencematerials(CRMs)
The control sample is run two or more times during the run,
is frequently the only strategy that can be employed for
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batch, or shift. The average is plotted on the X-chart and the
infrequently used analytical methods or for non-routine sample
absolute value of the difference between the high and low
types. If a CRM (from the National Institute of Standards and
values, the range, is plotted on the R-chart. If the average falls
Technology or other CRM producer) similar to the samples in
between the upper and lower control limits and the range falls
composition is tested with the samples, comparison of the
belowtheuppercontrollimit,theprocessisconsideredtobein
measured value to the assigned value of the CRM provides a
control. Fig. 1 shows the essential features of charts for
measure of confidence in the sample assays. Lacking a CRM,
averages and ranges.
any previously analyzed material may be used. In all cases, it
¯
6.3.2 The X-chart method (often called the control chart for
is important to retain as large a portion of such a material as
individuals) is useful for measurements that are made on a
possible and to tabulate the results, the method used, the date,
frequent or continual basis. It is appropriate for methods or
and the analyst. Materials and data thus obtained may have
instruments for which the usual mode of failure produces
important future statistical or control chart use.
relatively large shifts in results and the cost of a determination
6.4 Definitions:
precludes performing replicate analyses of control samples. Its
main characteristic is that it responds rapidly to sudden
6.4.1 mean:
relatively large changes in the analytical process, but it is not
H
X 5 X 1X 1…. X /n (1)
~ !
¯
1 2 n
as sensitive to small changes as the X- and R-chart method.
Each time the control material is analyzed, its value is plotted
where:
on the -chart. If the point plots between the upper and lower
n = the number of analytical values.
control limits, the analytical process is considered to be in
6.4.2 grand mea
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