ASTM E1866-97(2002)

Standard Guide for Establishing Spectrophotometer Performance Tests

SCOPE
1.1 This guide describes basic procedures that can be used to develop spectrophotometer performance tests. The guide is intended to be applicable to spectrophotometers operating in the ultraviolet, visible, near-infrared and mid-infrared regions.
1.2 This guide is not intended as a replacement for specific practices such as Practices E 275, E 925, E 932, E 958, E 1421, or E 1683 that exist for measuring performance of specific types of spectrophotometers. Instead, this guide is intended to provide guidelines in how similar practices should be developed when specific practices do not exist for a particular spectrophotometer type, or when specific practices are not applicable due to sampling or safety concerns. This guide can be used to develop performance tests for on-line process spectrophotometers.
1.3 This guide describes univariate level zero and level one tests, and multivariate level A and level B tests which can be implemented to measure spectrophotometer performance. These tests are designed to be used as rapid, routine checks of spectrophotometer performance. They are designed to uncover malfunctions or other changes in instrument operation, but do not specifically diagnose or quantitatively assess the malfunction or change. The tests are not intended for the comparison of spectrophotometers of different manufacture.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Mar-1997
• ICS: 17.180.30 - Optical measuring instruments
• ICS: 71.040.50 - Physicochemical methods of analysis
• Technical Committee: E13 - Molecular Spectroscopy and Separation Science
• Drafting Committee: E13.03 - Infrared and Near Infrared Spectroscopy

Relations

• Replaces: ASTM E1866-97 - Standard Guide for Establishing Spectrophotometer Performance Tests
• Effective Date: 10-Mar-1997
• Replaced By: ASTM E1866-97(2007) - Standard Guide for Establishing Spectrophotometer Performance Tests
• Effective Date: 01-Dec-2007
• Referred By: ASTM D8438/D8438M-23 - Standard Test Methods for Use of Hyperspectral Sensors for Soil Nutrient Analysis of Ground Based Samples
• Effective Date: 10-Mar-1997
• Referred By: ASTM D8470-22 - Standard Practice for Development and Implementation of Instrument Performance Tests for Use on Multivariate Online, At-Line and Laboratory Spectroscopic Based Analyzer Systems
• Effective Date: 10-Mar-1997
• Referred By: ASTM E2056-04(2016) - Standard Practice for Qualifying Spectrometers and Spectrophotometers for Use in Multivariate Analyses, Calibrated Using Surrogate Mixtures
• Effective Date: 10-Mar-1997
• Referred By: ASTM E1655-17 - Standard Practices for Infrared Multivariate Quantitative Analysis
• Effective Date: 10-Mar-1997
• Referred By: ASTM D8340-22 - Standard Practice for Performance-Based Qualification of Spectroscopic Analyzer Systems
• Effective Date: 10-Mar-1997
• Referred By: ASTM D7418-23 - Standard Practice for Set-Up and Operation of Fourier Transform Infrared (FT-IR) Spectrometers for In-Service Oil Condition Monitoring
• Effective Date: 10-Mar-1997
• Referred By: ASTM E925-09(2022) - Standard Practice for Monitoring the Calibration of Ultraviolet-Visible Spectrophotometers whose Spectral Bandwidth does not Exceed 2 nm
• Effective Date: 10-Mar-1997
• Referred By: ASTM E1421-99(2021) - Standard Practice for Describing and Measuring Performance of Fourier Transform Mid-Infrared (FT-MIR) Spectrometers: Level Zero and Level One Tests
• Effective Date: 10-Mar-1997
• Referred By: ASTM D6122-22 - Standard Practice for Validation of the Performance of Multivariate Online, At-Line, Field and Laboratory Infrared Spectrophotometer, and Raman Spectrometer Based Analyzer Systems
• Effective Date: 10-Mar-1997
• Referred By: ASTM D8321-22 - Standard Practice for Development and Validation of Multivariate Analyses for Use in Predicting Properties of Petroleum Products, Liquid Fuels, and Lubricants based on Spectroscopic Measurements
• Effective Date: 10-Mar-1997

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
Designation:E1866–97 (Reapproved2002)
Standard Guide for
Establishing Spectrophotometer Performance Tests
This standard is issued under the fixed designation E1866; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope E387 Test Method for Estimating Stray Radiant Power
RatioofSpectrophotometersbytheOpaqueFilterMethod
1.1 This guide describes basic procedures that can be used
E925 PracticeforthePeriodicCalibrationofNarrowBand-
to develop spectrophotometer performance tests. The guide is
Pass Spectrophotometers
intended to be applicable to spectrophotometers operating in
E932 Practice for Describing and Measuring Performance
the ultraviolet, visible, near-infrared and mid-infrared regions.
of Dispersive Infrared Spectrometers
1.2 This guide is not intended as a replacement for specific
E958 Practice for Measuring Practical Spectral Bandwidth
practicessuchasPracticesE275,E925,E932,E958,E1421,
of Ultraviolet-Visible Spectrophotometers
or E1683 that exist for measuring performance of specific
E1421 PracticeforDescribingandMeasuringPerformance
types of spectrophotometers. Instead, this guide is intended to
of Fourier Transform Infrared (FT-IR) Spectrometers:
provide guidelines in how similar practices should be devel-
Level Zero and Level One Tests
oped when specific practices do not exist for a particular
E1655 Practice for Infrared, Multivariate, Quantitative
spectrophotometer type, or when specific practices are not
Analysis
applicable due to sampling or safety concerns. This guide can
E1683 Practice for Testing the Performance of Scanning
be used to develop performance tests for on-line process
Raman Spectrometers
spectrophotometers.
1.3 This guide describes univariate level zero and level one
3. Terminology
tests, and multivariate level A and level B tests which can be
3.1 Definitions—For terminology relating to molecular
implemented to measure spectrophotometer performance.
spectroscopic methods, refer to Terminology E131.
These tests are designed to be used as rapid, routine checks of
3.2 Definitions of Terms Specific to This Standard:
spectrophotometer performance.They are designed to uncover
3.2.1 action limit, n—the limiting value from an instrument
malfunctions or other changes in instrument operation, but do
performance test, beyond which the spectrophotometer is
not specifically diagnose or quantitatively assess the malfunc-
expected to produce potentially invalid results.
tionorchange.Thetestsarenotintendedforthecomparisonof
3.2.2 check sample, n—a single pure compound, or a
spectrophotometers of different manufacture.
known,reproduciblemixtureofcompoundswhosespectrumis
1.4 This standard does not purport to address all of the
constant over time such that it can be used in a performance
safety concerns, if any, associated with its use. It is the
test.
responsibility of the user of this standard to establish appro-
3.2.3 level A test, n—a pass/fail spectrophotometer perfor-
priate safety and health practices and determine the applica-
mance test in which the spectrum of a check or test sample is
bility of regulatory limitations prior to use.
compared against historical spectra of the same sample via a
2. Referenced Documents multivariate analysis.
3.2.4 level B test, n—a pass/fail spectrophotometer perfor-
2.1 ASTM Standards:
mance test in which the spectrum of a check or test sample is
E131 Terminology Relating to Molecular Spectroscopy
analyzed using a multivariate model, and the results of the
E275 Practice for Describing and Measuring Performance
analysis are compared to historical results for prior analyses of
of Ultraviolet, Visible, and Near-Infrared Spectrophotom-
the same sample.
eters
3.2.5 level one (1) test, n—a simple series of measurements
designed to provide quantitative data on various aspects of
spectrophotometer performance and information on which to
This guide is under the jurisdiction of ASTM Committee E13 on Molecular
base the diagnosis of problems.
Spectroscopy and Separation Science and is the direct responsibility of Subcom-
3.2.6 level zero (0) test, n—a routine check of spectropho-
mittee E13.03 on Infrared and Near Infrared Spectroscopy.
tometer performance, which can be done in a few minutes,
Current edition approved Sept. 10, 2002. Published September 2002.
Annual Book of ASTM Standards, Vol 03.06. designed to visually detect significant changes in instrument
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E1866–97 (2002)
performance and provide a database to determine instrument Spectraldatausedinperformancetestsshouldbedateandtime
performance over time. stamped, and the results of the tests should be stored in a
historical database.
3.2.7 optical reference filter, n—an optical filter or other
device which can be inserted into the optical path in the
spectrophotometer or probe producing an absorption spectrum 6. Samples Used for Performance Testing
which is known to be constant over time such that it can be
6.1 Thesampleusedforperformancetestingischosentobe
used in place of a check or test sample in a performance test.
compatible with the spectrophotometer configuration, and to
3.2.8 test sample, n—a process or product sample, or a
providespectralfeatureswhichareadequateforthetestsbeing
mixture of process or product samples which has a constant
performed.
spectrum for a finite time period and which can be used in a
6.1.1 The sample used for performance testing should
performance test. Test samples and their spectra are generally
generallybeinthesamephysicalstate(gas,liquid,orsolid)as
not reproducible in the long term.
the samples to be analyzed during normal operation of the
spectrophotometer.
4. Significance and Use
6.1.2 The sample used for performance testing should be
4.1 If ASTM Committee E-13 has not specified an appro-
physically and chemically compatible with the samples ana-
priate test procedure for a specific type of spectrophotometer, lyzed during normal operation.
or if the sample specified by a Committee E-13 procedure is
6.1.3 The sample used for performance is chosen such that
incompatible with the intended spectrophotometer operation,
its spectrum is similar to the spectra which will be collected
then this guide can be used to develop practical performance
during normal operation.
tests.
6.1.4 The sample used for performance testing should have
4.1.1 For spectrophotometers which are equipped with per-
severalsignificantabsorbances(0.3 manent or semi-permanent sampling accessories, the test
thespectralrangeusedfornormaloperationofthespectropho-
sample specified in a Committee E-13 practice may not be
tometer.
compatible with the spectrophotometer configuration. For ex-
6.1.5 In order to adequately determine the photometric
ample,forFT-MIRinstrumentsequippedwithtransmittanceor
linearityoftheinstrument,thepeakabsorbanceforatleastone
IRSflowcells,testsbasedonpolystyrenefilmsareimpractical.
absorption band of the sample should be similar to and
In such cases, these guidelines suggest means by which the
preferablyslightlygreaterthanthelargestabsorbanceexpected
recommended test procedures can be modified so as to be
for samples measured during normal operation.
performed on a compatible test material.
6.2 Check Samples—Check samples are generally used for
4.1.2 For spectrophotometers used in process measure-
conducting performance tests. Check samples are single pure
ments, the choice of test materials may be limited due to
compoundsormixturesofcompoundsofdefinitecomposition.
process contamination and safety considerations. These guide-
6.2.1 Ifmixturesareutilizedaschecksamples,theymustbe
lines suggest means of developing performance tests based on
preparedinarepeatablemannerand,ifstored,storedsuchthat
materials which are compatible with the intended use of the
the mixture is stable over long periods of time. In preparing
spectrophotometer.
mixtures, components should be accurately pipetted or
4.2 Tests developed using these guidelines are intended to
weighed at ambient temperature. It is recommended that
allow the user to compare the performance of a spectropho-
mixtures be independently verified for composition prior to
tometeronanygivendaywithpriorperformance.Thetestsare
use.
intended to uncover malfunctions or other changes in instru-
6.2.2 While mixtures can be used as check samples, their
ment operation, but they are not designed to diagnose or
spectra may be adversely affected by temperature sensitive
quantitatively assess the malfunction or change. The tests are
interactions that may manifest themselves by wavelength
not intended for the comparison of spectrophotometers of
(frequency) and absorbance changes.
different manufacture.
6.3 Test Samples—A test sample is a process or product
sample or a mixture of process or product samples whose
5. Test Conditions
spectrum is expected to be constant for the time period it is
5.1 Whenconductingtheperformancetests,thespectropho- used in performance testing.The test sample must be stored in
tometer should be operated under the same conditions as will bulkquantitiesincontrolledconditionssuchthatthematerialis
be in effect during its intended use. Sufficient warm-up time stable over time.
should be allowed before the commencement of any measure-
6.3.1 Since test samples are often complex mixtures which
ments. cannot be synthetically reproduced, they can only be used for
5.1.1 Ifpossible,theopticalconfigurationusedformeasure-
performancetestingforlimitedtimeperiods.Iftestsamplesare
mentsoftestandchecksamplesshouldbeidenticaltothatused usedforthispurpose,collectionofhistoricaldataonanewtest
for normal operations. If identical optical configurations are
sample should be initiated before previous test samples are
not possible, the user should recognize that the performance depleted.Itisrecommendedthatnewtestsamplesbeanalyzed
tests may not measure the performance of the entire instru-
sequentially with old test samples at least 15 times before they
ment. are used to replace the old test sample. The 15 analyses must
5.1.2 Data collection and computation conditions should be performed over a time period that does not exceed one
generally be identical to those used in normal operation. month in duration.
E1866–97 (2002)
6.4 Optical Filters—An optical reference filter is an optical ricnoisetestsmaybeconductedonthespectrumofacheckor
filter or other optical device located in the spectrophotometer test sample at regions where the spectrum is relatively flat and
or in a fiber optic sample probe which produces an absorption the sample absorbance is minimal (<0.1).
spectrum which is known to be constant over time. This filter
7.2.1 For single beam spectrophotometers where back-
may be automatically inserted into the optical path to allow
groundandsamplespectraaremeasuredseparatelyatdifferent
instrument performance tests to be performed.
times, a 100% line spectrum is obtained by ratioing two
6.4.1 Optical filters are used principally with on-line pro-
successivebackgroundmeasurementstoobtainatransmittance
cessspectrophotometersequippedwithfiberopticprobeswhen
spectrum. If, during normal operation of the spectrophotom-
removal of the probe is inconvenient, precluding the use of
eter,backgroundsarecollectedwithareferencematerialinthe
check or test samples for routine instrument performance
optical path, then this same configuration should be used for
testing.
performance testing. Photometric noise calculations are pref-
6.4.2 If an optical filter is used routinely to check or correct
erably done directly on the transmittance spectrum. Alterna-
thespectraldatacollectionorcomputation,thenthesamefilter
tively, the transmittance spectrum may be converted to an
ispreferablynotusedforinstrumentperformancetesting.Ifthe
absorption spectrum by taking the negative log before the
same filter is used, then the part of the filter spectrum used in
photometric noise calculations.
the performance testing should preferably differ from that part
7.2.2 For double beam spectrophotometers, a 100% line
used to check or correct the instrument. For example, polysty-
spectrum is measured when the two beams are both empty,
rene filters are used to standardize (continuously check and
both contain empty matched cells, or both contain reference
correct) the wavelength scale of some dispersive NIR spectro-
samples in matched cells.
photometers. For such systems, polystyrene filters are prefer-
7.2.3 Photometric noise is measured by fitting a line to the
ably not to be employed for wavelength stability performance
spectrum over a short spectral region centered on the test
testing. If polystyrene filters are used, then the peaks used for
frequency (wavelength). The region should contain at least 11
wavelengthstabilitytestingshouldbedifferentfromthoseused
datapoints,preferablycontains101datapoints,andshouldnot
for standardizing the wavelength scale.
exceed 2% of the spectral range. The line is subtracted from
7. Univariate Measures of Spectrophotometer
thespectraldata,andtheRMSnoiseiscalculatedasthesquare
Performance
root of the mean square residual.
7.1 Energy Level Tests—Energy level tests are intended to
7.2.3.1 If T isthetransmittanceatthefrequency v,thenthe
i i
detect changes in the radiant power in the spectrophotometer
slope, m, and intercept, b, of a line through the n data points
beam. Decreases in energy levels may be associated with
centered at test frequency v are given by the following:
deterioration of the spectrophotometer source, with contami-
n(iT 2 (T (i
i i
m 5 (1)
nation or misalignment of optical surfaces in the light path, or
2 2
n(i 2 ~(i!
with malfunctions of the detector.
(i (T 2 (i(iT
7.1.1 For single beam spectrophotometers where back-
i i
b 5 (2)
2 2
n(i 2 ~(i!
groundandsamplespectraaremeasuredseparatelyatdifferent
times, energy level tests are generally conducted on a back-
The photometric noise is calculated as follows:
ground spectrum. For double beam spectrophotometers where
the ratio of background and sample beam intensities is mea- (~T 2 ~mi 1 b!!
i
Noise 5Π(3)
RMS
n 22
sureddirectly,energylevelscanbemeasuredifitispossibleto
block the sample beam.
The index i in Eq 1-3 runs from−(n − 1)/2 to (n − 1)/2 (n
7.1.2 Energy levels should be measured at at least three
must be odd).The intercept represents the transmittance at test
fixed frequencies (wavelengths), one each in the upper, middle
frequency v .
and lower third of the spec
...