ASTM D6122-15
(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. The validated analyzer results are expected to be statistically indistinguishable, over diverse samples whose spectra are neither outliers or nearest neighbor inliers, to those produced by the primary test method to within control limits established by control charts for the prespecified statistical confidence level.
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 met. Additional, optional ...
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 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. When there is adequate variation in property level, the statistical methodology of Practice D6708 is used to provide general validation of this equivalence over the complete operating range of the analyzer. For cases where there is inadequate property variation, methodology for level specific validation is 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 analyzer output (spectrum) produces a PPTMR for the treated material. The PPTMRs based on the analyzer outputs are compared to the PTMRs measured on the treated materials to determine the degree of agreement.
1.2 Performance Validation is conducted by calculating the precision and bias of ...
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Designation: D6122 − 15
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 four sequential
activities. (1) Analyzer Calibration—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. (2a) Correlation, where analyzer and Primary Test Method (PTM) measure
the same material—Once the diagnostic testing is completed, process stream samples are analyzed
using both the analyzer system and the corresponding PTM.Amathematical function is derived that
relates the analyzer output to the PTM. The application of this mathematical function to an analyzer
output produces a Predicted Primary Test Method Result (PPTMR) for the same material. (2b)
Correlation, where analyzer measures a material which is subjected to treatment before being
measured by the PTM—Once the diagnostic testing is completed, the process stream samples are
analyzed by the analyzer system. The same samples are subjected to a consistent treatment, and the
treatedsamplesareanalyzedbythePTM.Amathematicalfunctionisderivedthatrelatedtheanalyzer
output for the untreated sample to the Primary Test Method Result (PTMR) for the treated material.
Theapplicationofthemathematicalfunctiontotheanalyzeroutputfortheuntreatedmaterialproduces
a PPTMR for the treated material. (3) Probationary Validation—Once the relationship between the
analyzer output and PTMRs has been established, a probationary validation is performed using an
independentbutlimitedsetofmaterialsthatwerenotpartofthecorrelationactivity.Thisprobationary
validationisintendedtodemonstratethatthePPTMRsagreewiththePTMRstowithinuser-specified
requirements for the analyzer system application. (4) General and Continual Validation—After an
adequate number of PPTMRs and PTMRs have been accrued on materials that were not part of the
correlation activity, a comprehensive statistical assessment is performed to demonstrate that the
PPTMRs agree with the PTMRs to within user-specified requirements. Subsequent to a successful
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 and fourth of these activities.
“Correlation where analyzer measures a material which is subjected to treatment before being
measuredbythePTM”asoutlinedinthispracticeisintendedprimarilytobeappliedtobiofuelswhere
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.
1. Scope* of liquid petroleum products and fuels. The properties are
calculatedfromspectroscopicdatausingmultivariatemodeling
1.1 This practice covers requirements for the validation of
methods. The requirements include verification of adequate
measurementsmadebylaboratoryorprocess(onlineorat-line)
instrument performance, verification of the applicability of the
near-ormid-infraredanalyzers,orboth,usedinthecalculation
calibrationmodeltothespectrumofthesampleundertest,and
ofphysical,chemical,orqualityparameters(thatis,properties)
*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 − 15
verification that the degree of agreement between the results 1.4 This practice is intended as a review for experienced
calculated from the infrared measurements and the results persons.Fornovices,thispracticewillserveasanoverviewof
produced by the PTM used for the development of the techniques used to verify instrument performance, to verify
calibration model meets user-specified requirements. When model
...
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 − 13 D6122 − 15
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 four sequential
activities. (1) Analyzer Calibration—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. (2)(2a) CorrelationCorrelation, where analyzer and Primary Test Method
(PTM) measure the same material—Once the diagnostic testing is completed, process stream
samples are analyzed using both the analyzer system and the corresponding primary test method
(PTM). PTM. A mathematical function is derived that relates the analyzer output to the primary test
method (PTM). PTM. The application of this mathematical function to an analyzer output produces
a predicted primary test method result (PPTMR). Predicted Primary Test Method Result (PPTMR) for
the same material. (2b) Correlation, where analyzer measures a material which is subjected to
treatment before being measured by the PTM—Once the diagnostic testing is completed, the
process stream samples are analyzed by the analyzer system. The same samples are subjected to a
consistent treatment, and the treated samples are analyzed by the PTM. A mathematical function is
derived that related the analyzer output for the untreated sample to the Primary Test Method Result
(PTMR) for the treated material. The application of the mathematical function to the analyzer output
for the untreated material produces a PPTMR for the treated material. (3) Probationary Validation—
Once the relationship between the analyzer output and PTMRs has been established, a probationary
validation is performed using an independent but limited set of materials that were not part of the
correlation activity. This probationary validation is intended to demonstrate that the PPTMRs agree
with the PTMRs to within user-specified requirements for the analyzer system application. (4) Gen-
eral and Continual Validation—After an adequate number of PPTMRs and PTMRs have been
accrued on materials that were not part of the correlation activity, a comprehensive statistical
assessment is performed to demonstrate that the PPTMRs agree with the PTMRs to within
user-specified requirements. Subsequent to a successful 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 and
fourth 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 is intended primarily to 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.
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 May 1, 2013June 1, 2015. Published June 2013February 2016. Originally approved in 1997. Last previous edition approved in 2010 as
D6122 – 10.D6122 – 13. DOI: 10.1520/D6122-13.10.1520/D6122-15.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D6122 − 15
1. Scope*
1.1 This practice covers requirements for
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