ASTM D6122-19a
(Practice)Standard Practice for Validation of the Performance of Multivariate Online, At-Line, and Laboratory Infrared Spectrophotometer Based Analyzer Systems
Standard Practice for Validation of the Performance of Multivariate Online, At-Line, and Laboratory Infrared Spectrophotometer Based Analyzer Systems
SIGNIFICANCE AND USE
5.1 The primary purpose of this practice is to permit the user to validate numerical values produced by a multivariate, infrared or near-infrared laboratory or process (online or at-line) analyzer calibrated to measure a specific chemical concentration, chemical property, or physical property. If the analyzer results agree with the primary test method to within limits based on the multivariate model for the user-prespecified statistical confidence level, these results can be considered ’validated’ to the user pre-specified confidence limit for a specific application, and hence can be considered useful for that specific application.
5.2 Procedures are described for verifying that the instrument, the model, and the analyzer system are stable and properly operating.
5.3 A multivariate analyzer system inherently utilizes a multivariate calibration model. In practice, the model both implicitly and explicitly spans some subset of the population of all possible samples that could be in the complete multivariate sample space. The model is applicable only to samples that fall within the subset population used in the model construction. A sample measurement cannot be validated unless applicability is established. Applicability cannot be assumed.
5.3.1 Outlier detection methods are used to demonstrate applicability of the calibration model for the analysis of the process sample spectrum. The outlier detection limits are based on historical as well as theoretical criteria. The outlier detection methods are used to establish whether the results obtained by an analyzer are potentially valid. The validation procedures are based on mathematical test criteria that indicate whether the process sample spectrum is within the range spanned by the analyzer system calibration model. If the sample spectrum is an outlier, the analyzer result is invalid. If the sample spectrum is not an outlier, then the analyzer result is valid providing that all other requirements for validity are...
SCOPE
1.1 This practice covers requirements for the validation of measurements made by laboratory or process (online or at-line) near- or mid-infrared analyzers, or both, used in the calculation of physical, chemical, or quality parameters (that is, properties) of liquid petroleum products and fuels. The properties are calculated from spectroscopic data using multivariate modeling methods. The requirements include verification of adequate instrument performance, verification of the applicability of the calibration model to the spectrum of the sample under test, and verification that the uncertainties associated with the degree of agreement between the results calculated from the infrared measurements and the results produced by the PTM used for the development of the calibration model meets user-specified requirements. Initially, a limited number of validation samples representative of current production are used to do a local validation. When there is an adequate number of validation samples with sufficient variation in both property level and sample composition to span the model calibration space, the statistical methodology of Practice D6708 can be used to provide general validation of this equivalence over the complete operating range of the analyzer. For cases where adequate property and composition variation is not achieved, local validation shall continue to be used.
1.1.1 For some applications, the analyzer and PTM are applied to the same material. The application of the multivariate model to the analyzer output (spectrum) directly produces a PPTMR for the same material for which the spectrum was measured. The PPTMRs are compared to the PTMRs measured on the same materials to determine the degree of agreement.
1.1.2 For other applications, the material measured by the analyzer system is subjected to a consistent treatment prior to being analyzed by the PTM. The application of the multivariate model to the analyze...
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Designation: D6122 − 19a
Standard Practice for
Validation of the Performance of Multivariate Online, At-
Line, and Laboratory Infrared Spectrophotometer Based
1
Analyzer Systems
This standard is issued under the fixed designation D6122; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Operation of a laboratory or process stream analyzer system typically involves five sequential
activities. (1) Correlation—Prior to the initiation of the procedures described in this practice, a
multivariatemodelisderivedwhichrelatesthespectrumproducedbytheanalyzertothePrimaryTest
Method Result (PTMR). (1a) If the analyzer and Primary Test Method (PTM) measure the same
material, then the multivariate model directly relates the spectra to PTMR collected on the same
samples.Alternatively (1b) if the analyzer measures the spectra of a material that is subjected to
treatment prior to being measured by the PTM, then the multivariate model relates the spectra of
theuntreatedsampletothePTMRforthesamesampleaftertreatment. (2) Analyzer Qualification—
When an analyzer is initially installed, or after major maintenance has been performed, diagnostic
testing is performed to demonstrate that the analyzer meets the manufacturer’s specifications and
historical performance standards. These diagnostic tests may require that the analyzer be adjusted so
as to provide predetermined output levels for certain reference materials (3) Local Validation—A
local validation is performed using an independent but limited set of materials that were not part of
thecorrelationactivity.Thislocalvalidationisintendedtodemonstratethattheagreementbetweenthe
Predicted Primary Method Test Results (PPTMRs) and the PTMRs are consistent with expectations
basedonthemultivariatemodel. (4) General Validation—AfteranadequatenumberofPPTMRsand
PTMRs have been accrued on materials that were not part of the correlation activity and which
adequately span the multivariate model compositional space, a comprehensive statistical assessment
can be performed to demonstrate that the PPTMRs agree with the PTMRs to within user-specified
requirements. (5) Continual Validation—Subsequent to a successful local or general validation,
qualityassurancecontrolchartmonitoringofthedifferencesbetweenPPTMRandPTMRisconducted
duringnormaloperationoftheprocessanalyzersystemtodemonstratethattheagreementbetweenthe
PPTMRs and the PTMRs established during the GeneralValidation is maintained.This practice deals
with the third, fourth, and fifth of these activities.
“Correlation where analyzer measures a material which is subjected to treatment before being
measured by the PTM” as outlined in this practice can be applied to biofuels where the biofuel
materialisaddedataterminalorotherfacilityandnotincludedintheprocessstreammaterialsampled
bytheanalyzeratthebasestockmanufacturingfacility.The“treatment”shallbeaconstantpercentage
addition of the biofuels material to the basestock material. The correlation is deemed valid only for
the specific percentage addition and type of biofuel material used in its development.
1. Scope*
1 1.1 This practice covers requirements for the validation of
This practice is under the jurisdiction ofASTM Committee D02 on Petroleum
measurementsmadebylaboratoryorprocess(onlineorat-line)
Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcom-
mittee D02.25 on Performance Assessment and Validation of Process Stream
near-ormid-infraredanalyzers,orboth,usedinthecalculation
Analyzer Systems.
ofphysical,chemical,orqualityparameters(thatis,properties)
Current edition approved May 1, 2019. Published May 2019. Originally
of liquid petroleum products and fuels. The properties are
approved in 1997. Last previous edition approved in 2019 as D6122–19. DOI:
10.1520/D6122-19A. calculatedfromspectroscopicdatausingmultivariatemodeling
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D6122 − 19a
methods. The requirements include verification of adequate Error of Calibration (SEC) is a measure of how well the
instrument performance, verification of the applicability of the PTMRs and PPTMRs agree for this set of calibration samples.
calibrationmodeltothespectrumofthesampleundertest,and SEC includes contributions from spectrum measurement error,
verification that the uncertainties associated with the degree of PTM measurement error, and model error. Sample (type)
agreement between
...
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.
Designation: D6122 − 19 D6122 − 19a
Standard Practice for
Validation of the Performance of Multivariate Online, At-
Line, and Laboratory Infrared Spectrophotometer Based
1
Analyzer Systems
This standard is issued under the fixed designation D6122; 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.
INTRODUCTION
Operation of a laboratory or process stream analyzer system typically involves five sequential
activities. (1) Correlation—Prior to the initiation of the procedures described in this practice, a
multivariate model is derived which relates the spectrum produced by the analyzer to the Primary Test
Method Result (PTMR). (1a) If the analyzer and Primary Test Method (PTM) measure the same
material, then the multivariate model directly relates the spectra to PTMR collected on the same
samples. Alternatively (1b) if the analyzer measures the spectra of a material that is subjected to
treatment prior to being measured by the PTM, then the multivariate model relates the spectra of
the untreated sample to the PTMR for the same sample after treatment. (2) Analyzer Qualification—
When an analyzer is initially installed, or after major maintenance has been performed, diagnostic
testing is performed to demonstrate that the analyzer meets the manufacturer’s specifications and
historical performance standards. These diagnostic tests may require that the analyzer be adjusted so
as to provide predetermined output levels for certain reference materials (3) Local Validation—A
local validation is performed using an independent but limited set of materials that were not part of
the correlation activity. This local validation is intended to demonstrate that the agreement between the
Predicted Primary Method Test Results (PPTMRs) and the PTMRs are consistent with expectations
based on the multivariate model. (4) General Validation—After an adequate number of PPTMRs and
PTMRs have been accrued on materials that were not part of the correlation activity and which
adequately span the multivariate model compositional space, a comprehensive statistical assessment
can be performed to demonstrate that the PPTMRs agree with the PTMRs to within user-specified
requirements. (5) Continual Validation—Subsequent to a successful local or general validation,
quality assurance control chart monitoring of the differences between PPTMR and PTMR is conducted
during normal operation of the process analyzer system to demonstrate that the agreement between the
PPTMRs and the PTMRs established during the General Validation is maintained. This practice deals
with the third, fourth, and fifth of these activities.
“Correlation where analyzer measures a material which is subjected to treatment before being
measured by the PTM” as outlined in this practice can be applied to biofuels where the biofuel
material is added at a terminal or other facility and not included in the process stream material sampled
by the analyzer at the basestock manufacturing facility. The “treatment” shall be a constant percentage
addition of the biofuels material to the basestock material. The correlation is deemed valid only for
the specific percentage addition and type of biofuel material used in its development.
1. Scope*
1.1 This practice covers requirements for the validation of measurements made by laboratory or process (online or at-line) near-
or mid-infrared analyzers, or both, used in the calculation of physical, chemical, or quality parameters (that is, properties) of liquid
petroleum products and fuels. The properties are calculated from spectroscopic data using multivariate modeling methods. The
1
This practice is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.25 on Performance Assessment and Validation of Process Stream Analyzer Systems.
Current edition approved Jan. 1, 2019May 1, 2019. Published February 2019May 2019. Originally approved in 1997. Last previous edition approved in 20182019 as
D6122 – 18.D6122 – 19. DOI: 10.1520/D6122-19.10.1520/D6122-19A.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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