ASTM E1866-97

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 E275, E925, E932, E958, E1421, or E1683 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
• Technical Committee: E13 - Molecular Spectroscopy and Separation Science
• Drafting Committee: E13.03 - Infrared and Near Infrared Spectroscopy

Relations

• Replaced By: ASTM E1866-97(2002) - Standard Guide for Establishing Spectrophotometer Performance Tests
• 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
• 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

Standards Content (Sample)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 1866 – 97
Standard Guide for
Establishing Spectrophotometer Performance Tests
This standard is issued under the fixed designation E 1866; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope E 932 Practice for Describing and Measuring Performance
of Dispersive Infrared Spectrometers
1.1 This guide describes basic procedures that can be used
E 958 Practice for Measuring Practical Spectral Bandwidth
to develop spectrophotometer performance tests. The guide is
of Ultraviolet-Visible Spectrophotometers
intended to be applicable to spectrophotometers operating in
E 1421 Practice for Describing and Measuring Performance
the ultraviolet, visible, near-infrared and mid-infrared regions.
of Fourier Transform Infrared (FT-IR) Spectrometers:
1.2 This guide is not intended as a replacement for specific
Level Zero and Level One Tests
practices such as Practices E 275, E 925, E 932, E 958, E 1421,
E 1655 Practice for Infrared, Multivariate, Quantitative
or E 1683 that exist for measuring performance of specific
Analysis
types of spectrophotometers. Instead, this guide is intended to
E 1683 Practice for Testing the Performance of Scanning
provide guidelines in how similar practices should be devel-
Raman Spectrometers
oped when specific practices do not exist for a particular
spectrophotometer type, or when specific practices are not
3. Terminology
applicable due to sampling or safety concerns. This guide can
3.1 Definitions—For terminology relating to molecular
be used to develop performance tests for on-line process
spectroscopic methods, refer to Terminology E 131.
spectrophotometers.
3.2 Definitions of Terms Specific to This Standard:
1.3 This guide describes univariate level zero and level one
3.2.1 action limit, n—the limiting value from an instrument
tests, and multivariate level A and level B tests which can be
performance test, beyond which the spectrophotometer is
implemented to measure spectrophotometer performance.
expected to produce potentially invalid results.
These tests are designed to be used as rapid, routine checks of
3.2.2 check sample, n—a single pure compound, or a
spectrophotometer performance. They are designed to uncover
known, reproducible mixture of compounds whose spectrum is
malfunctions or other changes in instrument operation, but do
constant over time such that it can be used in a performance
not specifically diagnose or quantitatively assess the malfunc-
test.
tion or change. The tests are not intended for the comparison of
3.2.3 level A test, n—a pass/fail spectrophotometer perfor-
spectrophotometers of different manufacture.
mance test in which the spectrum of a check or test sample is
1.4 This standard does not purport to address all of the
compared against historical spectra of the same sample via a
safety concerns, if any, associated with its use. It is the
multivariate analysis.
responsibility of the user of this standard to establish appro-
3.2.4 level B 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.
analyzed using a multivariate model, and the results of the
2. Referenced Documents analysis are compared to historical results for prior analyses of
the same sample.
2.1 ASTM Standards:
3.2.5 level one (1) test, n—a simple series of measurements
E 131 Terminology Relating to Molecular Spectroscopy
designed to provide quantitative data on various aspects of
E 275 Practice for Describing and Measuring Performance
spectrophotometer performance and information on which to
of Ultraviolet, Visible, and Near-Infrared Spectrophotom-
base the diagnosis of problems.
eters
3.2.6 level zero (0) test, n—a routine check of spectropho-
E 387 Test Method for Estimating Stray Radiant Power
tometer performance, which can be done in a few minutes,
Ratio of Spectrophotometers by the Opaque Filter Method
designed to visually detect significant changes in instrument
E 925 Practice for the Periodic Calibration of Narrow Band-
performance and provide a database to determine instrument
Pass Spectrophotometers
performance over time.
3.2.7 optical reference filter, n—an optical filter or other
This guide is under the jurisdiction of ASTM Committee E-13 on Molecular
device which can be inserted into the optical path in the
Spectroscopy and is the direct responsibility of Subcommittee E13.11on Chemo-
metrics. spectrophotometer or probe producing an absorption spectrum
Current edition approved March 10, 1997. Published May 1997.
which is known to be constant over time such that it can be
Annual Book of ASTM Standards, Vol 03.06.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E 1866
used in place of a check or test sample in a performance test. provide spectral features which are adequate for the tests being
3.2.8 test sample, n—a process or product sample, or a performed.
mixture of process or product samples which has a constant
6.1.1 The sample used for performance testing should
spectrum for a finite time period and which can be used in a
generally be in the same physical state (gas, liquid, or solid) as
performance test. Test samples and their spectra are generally
the samples to be analyzed during normal operation of the
not reproducible in the long term.
spectrophotometer.
6.1.2 The sample used for performance testing should be
4. Significance and Use
physically and chemically compatible with the samples ana-
4.1 If ASTM Committee E-13 has not specified an appro-
lyzed during normal operation.
priate test procedure for a specific type of spectrophotometer,
6.1.3 The sample used for performance is chosen such that
or if the sample specified by a Committee E-13 procedure is
its spectrum is similar to the spectra which will be collected
incompatible with the intended spectrophotometer operation,
during normal operation.
then this guide can be used to develop practical performance
6.1.4 The sample used for performance testing should have
tests.
several significant absorbances (0.3 < absorbance < 1.0) across
4.1.1 For spectrophotometers which are equipped with per-
the spectral range used for normal operation of the spectropho-
manent or semi-permanent sampling accessories, the test
tometer.
sample specified in a Committee E-13 practice may not be
6.1.5 In order to adequately determine the photometric
compatible with the spectrophotometer configuration. For ex-
linearity of the instrument, the peak absorbance for at least one
ample, for FT-MIR instruments equipped with transmittance or
absorption band of the sample should be similar to and
IRS flow cells, tests based on polystyrene films are impractical.
preferably slightly greater than the largest absorbance expected
In such cases, these guidelines suggest means by which the
for samples measured during normal operation.
recommended test procedures can be modified so as to be
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
compounds or mixtures of compounds of definite composition.
process contamination and safety considerations. These guide-
6.2.1 If mixtures are utilized as check samples, they must be
lines suggest means of developing performance tests based on
prepared in a repeatable manner and, if stored, stored such that
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
tometer on any given day with prior performance. The tests are
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 When conducting the performance tests, the spectropho-
used in performance testing. The test sample must be stored in
tometer should be operated under the same conditions as will
bulk quantities in controlled conditions such that the material is
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 If possible, the optical configuration used for measure-
performance testing for limited time periods. If test samples are
ments of test and check samples should be identical to that used
used for this purpose, collection of historical data on a new test
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. It is recommended that new test samples be analyzed
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.
Spectral data used in performance tests should be date and time
6.4 Optical Filters—An optical reference filter is an optical
stamped, and the results of the tests should be stored in a
filter or other optical device located in the spectrophotometer
historical database.
or in a fiber optic sample probe which produces an absorption
6. Samples Used for Performance Testing
spectrum which is known to be constant over time. This filter
6.1 The sample used for performance testing is chosen to be may be automatically inserted into the optical path to allow
compatible with the spectrophotometer configuration, and to instrument performance tests to be performed.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E 1866
6.4.1 Optical filters are used principally with on-line pro- successive background measurements to obtain a transmittance
cess spectrophotometers equipped with fiber optic probes when spectrum. If, during normal operation of the spectrophotom-
removal of the probe is inconvenient, precluding the use of eter, backgrounds are collected with a reference material in the
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-
the spectral data collection or computation, then the same filter tively, the transmittance spectrum may be converted to an
is preferably not used for instrument performance testing. If the 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
wavelength stability testing should be different from those used
data points, preferably contains 101 data points, and should not
for standardizing the wavelength scale.
exceed 2 % of the spectral range. The line is subtracted from
the spectral data, and the RMS noise is calculated as the square
7. Univariate Measures of Spectrophotometer
root of the mean square residual.
Performance
7.2.3.1 If T is the transmittance at the frequency v , then the
i i
7.1 Energy Level Tests—Energy level tests are intended to
slope, m, and intercept, b, of a line through the n data points
detect changes in the radiant power in the spectrophotometer
centered at test frequency v are given by the following:
beam. Decreases in energy levels may be associated with
n(iT 2 (T (i
i i
deterioration of the spectrophotometer source, with contami-
m 5 (1)
2 2
n(i 2 ~(i!
nation or misalignment of optical surfaces in the light path, or
with malfunctions of the detector.
(i (T 2 (i(iT
i i
b 5 (2)
2 2
7.1.1 For single beam spectrophotometers where back-
n(i 2 ~(i!
ground and sample spectra are measured separately at different
The photometric noise is calculated as follows:
times, energy level tests are generally conducted on a back-
ground spectrum. For double beam spectrophotometers where
( T 2 mi 1 b!!
~ ~
i
Noise 5 (3)
˛
RMS
the ratio of background and sample beam intensities is mea-
n 2 2
sured directly, energy levels can be measured if it is possible to
The index i in Eq 1-3 runs from − (n − 1)/2
...