ASTM D6259-98(2004)

Standard Practice for Determination of a Pooled Limit of Quantitation

SIGNIFICANCE AND USE
In a single laboratory, the limit of quantitation, LOQ, equal to ten standard deviations has been recommended.4 A test result at this LOQ has an uncertainty of ±30 % at the 99 % confidence level. Similarly here, as a general estimate, the PLOQ, equal to ten repeatability standard deviations is recommended. A test result at this PLOQ has an uncertainty of ±30 % at the 99 % confidence level.
Values below the PLOQ are deemed to be too uncertain for meaningful use in commerce, or in regulatory activities.
Many test methods never find application outside their PLOQ. However, in the quest for ever more sensitive procedures, it can become difficult to distinguish an analytical response from background noise with the technology at hand. Test methods defective in design or poorly executed may also function outside their PLOQ.
SCOPE
1.1 This practice covers the determination of a lower quantitative limit for a test method for an analyte. The determined lower limit is hereinafter referred to as the pooled limit of quantitation.
1.2 Applicable test methods will produce test results greater than zero. Examples are those test methods that measure sample composition.

General Information

• Status: Historical
• Publication Date: 30-Apr-2004
• ICS: 19.020 - Test conditions and procedures in general
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.94 - Coordinating Subcommittee on Quality Assurance and Statistics

Relations

• Replaces: ASTM D6259-98 - Standard Practice for Determination of a Pooled Limit of Quantitation
• Effective Date: 01-May-2004
• Replaced By: ASTM D6259-98(2010) - Standard Practice for Determination of a Pooled Limit of Quantitation
• Effective Date: 01-Jul-2010
• Referred By: ASTM D4294-21 - Standard Test Method for Sulfur in Petroleum and Petroleum Products by Energy Dispersive X-ray Fluorescence Spectrometry
• Effective Date: 01-May-2004
• Referred By: ASTM D8146-22 - Standard Guide for Evaluating Test Method Capability and Fitness for Use
• Effective Date: 01-May-2004
• Referred By: ASTM D7039-15a(2020) - Standard Test Method for Sulfur in Gasoline, Diesel Fuel, Jet Fuel, Kerosine, Biodiesel, Biodiesel Blends, and Gasoline-Ethanol Blends by Monochromatic Wavelength Dispersive X-ray Fluorescence Spectrometry
• Effective Date: 01-May-2004
• Referred By: ASTM D2622-21 - Standard Test Method for Sulfur in Petroleum Products by Wavelength Dispersive X-ray Fluorescence Spectrometry
• Effective Date: 01-May-2004
• Referred By: ASTM D8056-18 - Standard Guide for Elemental Analysis of Crude Oil
• Effective Date: 01-May-2004
• Referred By: ASTM D7372-21 - Standard Guide for Analysis and Interpretation of Proficiency Test Program Results
• Effective Date: 01-May-2004
• Referred By: ASTM D8252-19e1 - Standard Test Method for Vanadium and Nickel in Crude and Residual Oil by X-ray Spectrometry
• Effective Date: 01-May-2004

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
An American National Standard
Designation:D6259–98 (Reapproved 2004)
Standard Practice for
Determination of a Pooled Limit of Quantitation
This standard is issued under the fixed designation D6259; 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.
may prepare the test specimens, a second measure the dimensions, and a
1. Scope
third measure the mass in a test method for measuring density.
1.1 This practice covers the determination of a lower
NOTE 2—By in the shortest practical period of time is meant that the
quantitative limit for a test method for an analyte. The
test results, at least for one material, are obtained in a time period not less
determined lower limit is hereinafter referred to as the pooled
than in normal testing and not so long as to permit significant change in
limit of quantitation. test material, equipment, or environment. See Terminology E456.
1.2 Applicable test methods will produce test results greater
3.2 Acronyms:
than zero. Examples are those test methods that measure
3.2.1 PLOQ, n—pooled limit of quantitation.
sample composition.
4. Summary of Practice
2. Referenced Documents
4.1 Determine the standard deviation of a test result, under
2.1 ASTM Standards:
repeatability conditions, at progressively higher levels of the
E456 Terminology Relating to Quality and Statistics
analyte until the ratio of measured level to standard deviation
E691 Practice for Conducting an Interlaboratory Study to
becomes greater than ten and remains so.
Determine the Precision of a Test Method
2.2 ASTM Adjuncts: 5. Significance and Use
D2PP, Determination of Precision and Bias Data for Use in
5.1 In a single laboratory, the limit of quantitation, LOQ,
Test Methods for Petroleum Products
equaltotenstandarddeviationshasbeenrecommended. Atest
result at this LOQ has an uncertainty of 630 % at the 99 %
3. Terminology
confidence level. Similarly here, as a general estimate, the
3.1 Definitions:
PLOQ, equal to ten repeatability standard deviations is recom-
3.1.1 pooled limit of quantitation, n—level of property or
mended. A test result at this PLOQ has an uncertainty of
concentration of analyte above which quantitative test results
630 % at the 99 % confidence level.
can be obtained with a specified degree of confidence. See
5.2 Values below the PLOQ are deemed to be too uncertain
3.2.1 for acronym.
for meaningful use in commerce, or in regulatory activities.
3.1.2 repeatability conditions, n—conditions under which
5.3 Many test methods never find application outside their
test results are obtained with the same test method in the same
PLOQ. However, in the quest for ever more sensitive proce-
laboratorybythesameoperatorwiththesameequipmentinthe
dures, it can become difficult to distinguish an analytical
shortest practical period of time using test units or test
response from background noise with the technology at hand.
specimens taken at random from a single quantity of material
Test methods defective in design or poorly executed may also
that is as nearly homogeneous as possible (see 10.3 of Practice
function outside their PLOQ.
E691.)
6. Procedure
NOTE 1—The same operator, same equipment requirement means that
6.1 Makethepreparationsoutlinedin6.2,thencarryoutone
for a particular step in the measurement process the same combination of
operator and equipment is used for every test result. Thus, one operator
of the procedures described in 6.3.
6.2 Preparations:
6.2.1 Select Test Levels—Decide the objective of the test
This practice is under the jurisdiction of CommitteeD02 on Petroleum Products
method, the range of typical samples it is expected to cover.
and Lubricants and is the direct responsibility of Subcommittee D02.94 on
Name a set of test levels covering this range and spaced to
Coordinating Subcommittee on Quality Assurance and Statistics.
Current edition approved May 1, 2004. Published June 2004. Originally bracket the PLOQ. In some cases, the PLOQ will be well
approved in 1998. Last previous edition approved in 1998 as D5259–98. DOI:
below the useful range. Then, it is only necessary to determine
10.1520/D6259-98R04.
a less than value.
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. Keith, L. H., et al, “Principles of Environmental Analysis,” Analytical Chem-
Withdrawn and no longer available from ASTM International. istry, American Chemical Society, Vol 55, 1983, p. 227.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D6259–98 (2004)
TABLE 1 Interlaboratory Study Examples
6.3 Continue with 6.3.1. However, since the PLOQ depends
Within Laboratories on the attainable precision, there can be cases where a
Ratio Mean/Standard
Sample Mean laboratory-specific precision and LOQ are needed by an
Standard Degrees of
Deviation
Deviation Freedom
individual laboratory for a special purpose. If the decision is
A
S8 110.0 44.72 10 2.5 made to determine the LOQ in a single laboratory, proceed to
A
S1 640.0 100.0 10 6.4
6.3.2.
A
S3 870.0 89.44 10 9.7
6.3.1 Interlaboratory—Conduct the interlaboratory study to
S6 1180 94.87 10 12.4
S2 1272 78.17 9 16.3 determine precision in a normal fashion making sure that
S7 2505 136.0 10 18.4
appropriate samples are included. Proceed to the calcu
...