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ASTM E958-93(1999)

(Practice)

Standard Practice for Measuring Practical Spectral Bandwidth of Ultraviolet-Visible Spectrophotometers

Standard Practice for Measuring Practical Spectral Bandwidth of Ultraviolet-Visible Spectrophotometers

SCOPE
1.1 This practice describes a procedure for measuring the practical spectral bandwidth of a spectrophotometer in the wavelength region of 185 to 820 nm. Practical spectral bandwidth is the spectral bandwidth of an instrument operated at a given integration period and a given signal-to-noise ratio.  
1.2 This practice is applicable to instruments that utilize servo-operated slits and maintain a constant period and a constant signal-to-noise ratio as the wavelength is automatically scanned. It is also applicable to instruments that utilize fixed slits and maintain a constant servo loop gain by automatically varying gain or dynode voltage. In this latter case, the signal-to-noise ratio varies with wavelength. It can also be used on instruments that utilize some combination of the two designs, as well as on those that vary the period during the scan. For digitized instruments, refer to the manufacturer's manual.  
1.3 This practice does not cover the measurement of limiting spectral bandwidth, defined as the minimum spectral bandwidth achievable under optimum experimental conditions.  
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-Feb-1999
ICS
17.180.30 - Optical measuring instruments
Technical Committee
E13 - Molecular Spectroscopy and Separation Science
Drafting Committee
E13.01 - Ultra-Violet, Visible, and Luminescence Spectroscopy
Current Stage
Ref Project

Relations

Replaced By
ASTM E958-93(2005) - Standard Practice for Measuring Practical Spectral Bandwidth of Ultraviolet-Visible Spectrophotometers
Effective Date
01-Apr-2005
Referred By
ASTM E2153-01(2023) - Standard Practice for Obtaining Bispectral Photometric Data for Evaluation of Fluorescent Color
Effective Date
10-Feb-1999
Referred By
ASTM D5463-18 - Standard Guide for Use of Test Kits to Measure Inorganic Constituents in Water
Effective Date
10-Feb-1999
Referred By
ASTM E275-08(2022) - Standard Practice for Describing and Measuring Performance of Ultraviolet and Visible Spectrophotometers
Effective Date
10-Feb-1999
Referred By
ASTM ISO/ASTM51205-17 - Standard Practice for Use of a Ceric-Cerous Sulfate Dosimetry System
Effective Date
10-Feb-1999
Referred By
ASTM E1164-12(2023)e1 - Standard Practice for Obtaining Spectrometric Data for Object-Color Evaluation
Effective Date
10-Feb-1999
Referred By
ASTM ISO/ASTM51538-17 - Standard Practice for Use of the Ethanol-Chlorobenzene Dosimetry System
Effective Date
10-Feb-1999
Referred By
ASTM E1866-97(2021) - Standard Guide for Establishing Spectrophotometer Performance Tests
Effective Date
10-Feb-1999
Referred By
ASTM ISO/ASTM51401-13 - Standard Practice for Use of a Dichromate Dosimetry System
Effective Date
10-Feb-1999
Referred By
ASTM E1341-16(2020) - Standard Practice for Obtaining Spectroradiometric Data from Radiant Sources for Colorimetry
Effective Date
10-Feb-1999
Referred By
ASTM ISO/ASTM51310-22 - Standard Practice for Use of a Radiochromic Optical Waveguide Dosimetry System
Effective Date
10-Feb-1999
Referred By
ASTM E169-16(2022) - Standard Practices for General Techniques of Ultraviolet-Visible Quantitative Analysis
Effective Date
10-Feb-1999
Referred By
ASTM ISO/ASTM51026-15 - Standard Practice for Using the Fricke Dosimetry System
Effective Date
10-Feb-1999
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-Feb-1999
Referred By
ASTM E2056-04(2016) - Standard Practice for Qualifying Spectrometers and Spectrophotometers for Use in Multivariate Analyses, Calibrated Using Surrogate Mixtures
Effective Date
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ASTM E958-93(1999) - Standard Practice for Measuring Practical Spectral Bandwidth of Ultraviolet-Visible SpectrophotometersASTM E958-93(1999) - Standard Practice for Measuring Practical Spectral Bandwidth of Ultraviolet-Visible Spectrophotometers
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ASTM E958-93(1999) - Standard Practice for Measuring Practical Spectral Bandwidth of Ultraviolet-Visible Spectrophotometers
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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:E958–93 (Reapproved 1999)
Standard Practice for
Measuring Practical Spectral Bandwidth of Ultraviolet-
Visible Spectrophotometers
This standard is issued under the fixed designation E 958; 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 3. Terminology
1.1 This practice describes a procedure for measuring the 3.1 Definitions:
practical spectral bandwidth of a spectrophotometer in the 3.1.1 integration period—the time, in seconds, required for
wavelength region of 185 to 820 nm. Practical spectral the pen or other indicator to move 98.6 % of its maximum
bandwidth is the spectral bandwidth of an instrument operated travel in response to a step function.
at a given integration period and a given signal-to-noise ratio. 3.1.2 practical spectral bandwidth, designated by the sym-
1.2 This practice is applicable to instruments that utilize bol:
servo-operated slits and maintain a constant period and a
p
~Dl! (1)
S/N
constant signal-to-noise ratio as the wavelength is automati-
cally scanned. It is also applicable to instruments that utilize
where:
fixed slits and maintain a constant servo loop gain by auto- Dl = spectral bandwidth,
maticallyvaryinggainordynodevoltage.Inthislattercase,the p = integration period, and
S/N = signal-to-noise ratio measured at or near 100 % T.
signal-to-noiseratiovarieswithwavelength.Itcanalsobeused
3.1.3 signal-to-noise ratio—the ratio of the signal, S,tothe
on instruments that utilize some combination of the two
noise, N, as indicated by the readout indicator. The recom-
designs, as well as on those that vary the period during the
mended measure of noise is the maximum peak-to-peak
scan. For digitized instruments, refer to the manufacturer’s
excursion of the indicator averaged over a series of five
manual.
successive intervals, each of duration ten times the integration
1.3 This practice does not cover the measurement of limit-
period. (This measure of noise is about five times the root-
ing spectral bandwidth, defined as the minimum spectral
mean-square noise.)
bandwidthachievableunderoptimumexperimentalconditions.
3.1.4 spectral bandwidth—the wavelength interval of radia-
1.4 This standard does not purport to address all of the
tion leaving the exit slit of a monochromator measured at half
safety concerns, if any, associated with its use. It is the
the peak detected radiant power. It is not synonymous with
responsibility of the user of this standard to establish appro-
spectral slit width, which is the product of the mechanical slit
priate safety and health practices and determine the applica-
width and the reciprocal linear dispersion of the spectropho-
bility of regulatory limitations prior to use.
tometer.
2. Referenced Documents
4. Summary of Practice
2.1 ASTM Standards:
4.1 The pen period and signal-to-noise ratio are set at the
E 131 Terminology Relating to Molecular Spectroscopy
desired values when the instrument is operated with its normal
E 275 Practice for Describing and Measuring Performance
light source and adjusted to read close to 100 % T. The
of Ultraviolet, Visible, and Near Infrared Spectrophotom-
mechanical slit width, or the indicated spectral bandwidth,
eters
required to give the desired signal-to-noise ratio is recorded.
The continuum source is replaced with a line emission source,
such as a mercury lamp, and the apparent half-intensity
This practice is under the jurisdiction ofASTM Committee E-13 on Molecular
Spectroscopy and is the direct responsibility of Subcommittee E13.01on Ultraviolet
bandwidth of an emission line occurring in the wavelength
and Visible Spectroscopy.
region of interest is measured using the same slit width, or
Current edition approved Dec. 15, 1993. Published February 1994. Originally
indicated spectral bandwidth, as was used to establish the
published as E 958 – 83. Last previous edition E 958 – 83 (1989).
Annual Book of ASTM Standards, Vol 03.06. signal-to-noise ratio with the continuum source.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E958
5. Significance and Use for measuring the spectral bandwidth of ultraviolet/visible
instruments at the levels of resolution encountered in most
5.1 This practice should be used by a person who develops
commercial instruments.All of the lines listed have widths less
an analytical method to ensure that the spectral bandwidths
than 0.02 nm, suitable for measuring spectral bandwidths of
cited in the practice are actually the ones used.
greater than 0.2 nm. The wavelengths of these lines in
NOTE 1—The method developer should establish the spectral band-
nanometres are listed in the first column. Values refer to
widths that can be used to obtain satisfactory results.
measurements in standard air (760 nm, 15°C) except for the
5.2 This practice should be used to determine whether a
two lines below 200 nm. The wavelength for these lines refer
spectral bandwidth specified in a method can be realized with
to a nitrogen atmosphere at 760 nm and 15°C.
a given spectrophotometer and thus whether the instrument is
6.1.1 The second column in Table 1 lists the emitter gas of
suitable for use in this application.
six sources. Only sources operating at low pressure should be
5.3 This practice allows the user of a spectrophotometer to
used, as line broadening can introduce errors. The hydrogen,
determine the actual spectral bandwidth of the instrument
deuterium, and mercury lamps used to obtain these data were
under a given set of conditions and to compare the result to the
Beckman lamps operated on Beckman spectrophotometer
spectral bandwidth calculated from data given in the manufac-
power supplies. The other lamps are all of the “pencil-lamp”
3 4
turer’s literature or indicated by the instrument.
type. A mercury vapor Pen-Ray lamp was used to obtain the
5.4 Instrument manufacturers can use this practice to mea-
data shown in Fig. 1. In many applications the mercury and
sure and describe the practical spectral bandwidth of an
hydrogen (or deuterium) lines suffice.
instrument over its entire wavelength operating range. This
practice is highly prefered to the general practice of stating the
Suitable lamps are available from laboratory supply houses as well as
limiting or the theoretical spectral bandwidth at a single
manufacturers, which include UVP, Inc., 5100 Walnut Grove Ave., P.O. Box 1501,
wavelength.
San Gabriel, CA 91778-1501; Spectronics Corp., 956 Brush Hollow Rd., P.O. Box
483, Westbury, NY 11590-0483; Jelight Co., Inc., 23052Alcalde, Unit E, P.O. Box
2632, Laguna Hills, CA 92653-2632; and BHK, Inc., 2885 Metropolitan Place,
6. Test Materials and Apparatus
Pomona, CA 91767.
6.1 Table 1 lists reference emission lines that may be used Available from UVP, Inc.
TABLE 1 Emission Lines Useful for Measuring Spectral Bandwidth
Reference Line,
Emitter Intensity Nearest Neighbor, nm Separation, nm I /I Weak Neighbor, nm
Neighbor Reference
nm
184.91 Hg 8 194.17 9.26 0.13
194.17 Hg 8 184.91 9.26 0.13 197.33
205.29 Hg 4 202.70 2.59 0.08
226.22 Hg 5 237.83 11.61 0.06 226.03
253.65 Hg 10 . . . 253.48
275.28 Hg 5 280.35 5.07 0.08
289.36 Hg 6 296.73 7.37 0.42
296.73 Hg 8 302.15 5.42 0.04
318.77 He 5 294.51 24.26 0.06
334.15 Hg 7 313.18 20.97 0.70
341.79 Ne 5 344.77 2.98 0.20
359.35 Ne 5 352.05 7.30 0.14 360.02
388.87 He 7 447.15 58.28 0.04
404.66 Hg 8 407.78 3.12 0.04
427.40 Kr 5 431.96 4.56 0.28 428.30
435.95 Hg 9 407.78 28.17 0.02 435.75
447.15 He 5 471.31 24.16 0.04
471.31 He 4 492.19 20.88 0.25
486.0 D . . . .
486.13 H 6 492.87 6.74 0.03 485.66
501.57 He 5 492.19 9.38 0.06
546.07 Hg 8 577.12 31.05 0.04
557.03 Kr 3 587.09 30.06 0.30 556.22
587.56 He 7 706.52 118.96 0.03 667.82
603.00 Ne 5 607.43 4.43 0.54
614.31 Ne 7 616.36 2.05 0.04
626.65 Ne 6 630.48 3.83 0.07
640.23 Ne 7 638.30 1.93 0.11
656.1 D . . . .
656.28 H 7 . . . 656.99
667.82 He 5 706.52 38.70 0.50
692.95 Ne 6 703.24 10.29 0.45
703.24 Ne 7 692.95 10.29 0.06 702.41
724.52 Ne 5 703.24 21.28 0.02 717.39
743.89 Ne 4 724.52 19.37 1.4 748.89
785.48 Kr 3 769.45 16.03 0.7
819.01 Kr 2 811.29 7.72 3.1
E958
signal-to-noise at a given integration period. This is best
accomplished by first establishing the desired period. Next
determine the slit widths required to yield a given signal-to-
noise ratio throughout the region of interest using the standard
continuum source of the instrument. Then use appropriate line
sources to illuminate the monochromator, and record the
spectral bandwidths obtained at the appropriate mechanical slit
widths for the wavelengths in question.
7.1.1 Although the integration period may be indicated on
the instrument or in the manufacturer’s literature, check the
value as follows:
FIG. 1 Comparison of Measured and Calculated Spectral
7.1.1.1 For recording instruments, set the wavelength at any
Bandwidths
convenient position and adjust the 0 and 100 % T controls for
normal recorder presentation. Using 100 % T as the base line,
block the sample beam and measure the time required for the
6.1.2 Relativeintensitydataforthereferencelinesaregiven
pen to reach the 2 % T level (Note 2).
in the third column of Table 1. The data refer to measurements
NOTE 2—The time may be measured with a stopwatch or from the
made with a double prism-grating spectrophotometer equipped
distance the chart moves, if a fast chart speed recorder is being used.
with a silica window S-20 photomultiplier (RCA-C70109E).
Integrationperiodsof1sorlesscanonlybeestimatedbyeithertechnique,
These intensities will be different when using detectors of
but generally this estimate is adequate to determine if the indicated period
different spectral sensitivity. They may also vary somewhat
is approximately correct.
amongsources.Allofthelinesareintenseones,butallmaynot
7.1.1.2 For instruments that can be operated only in the
alwaysbesufficientlyintensetoallowthespectrophotometerto
absorbance mode, follow the same procedure, with the excep-
be operated with very narrow slit widths.
tion that 0 A replaces 100 % T and 1.7 A replaces 2 % T.
6.1.3 Informationonnearestneighborsofappreciableinten-
sity is needed in order to set an upper limit on the measurable 7.1.2 The signal-to-noise ratio is measured as follows:
spectral bandwidth. If the resolution of the instrument in 7.1.2.1 Set the instrument at a convenient wavelength and
question is so poor that two lines or bands of the test source or adjust the pen to read either 100 % T or 0 A. For low-noise
sample overlap, the measured half bandwidth will not indicate levels use an expanded scale, if available.
the spectral bandwidth of the instrument. Very few of the lines
7.1.2.2 Adjust the slit width either to its normal value or to
listed in Table 1 are so well isolated from other lines of a value that gives the desired signal-to-noise ratio.
appreciable intensity that they could always be used without
7.1.2.3 Disengage the wavelength drive, start the chart
interference or overlap. The atomic hydrogen (deuterium) line
drive, and allow the pen to record for at least 2 min or 50
at 656 nm and the very intense mercury resonance line at 253
integration periods, whichever is longer.
nm fall in a category of “isolation,” but in all other cases
7.1.2.4 Divide the recording into five approximately equal
interfering lines are nearby. The nearest neighboring lines
segments and determine the maximum peak-to-peak excursion
having an intensity more than 15 % of the reference lines are
in each segment (Note 3).
given in the fourth column of Table 1. The separation in
NOTE 3—Care should be taken that the noise level is not partially
nanometers between the reference and nearest neighbor lines is
obscured by a detectable recorder dead zone.
listed in the fifth column. In general, lines cannot be used for
a spectral bandwidth test when the spectral bandwidth exceeds
7.1.2.5 Average the five readings to obtain the noise, N.
one half the separation between reference and nearest neighbor
7.1.2.6 If a % T recording is being used, divide 100 by N to
lines.
obtain the signal-to-noise ratio, S/N. If an absorbance record-
6.1.4 To some extent this rule can be modified by the
ing is being used, divide 0.43 by N to determine S/N.
relative intensities of neighbor to reference lines. This ratio,
7.1.2.7 The signal-to-noise ratio should be independent of
I /I , is listed in column 6. Neighboring lines
neighbor reference wavelength for a given source and detector combination, but it
having an intensity less than 15 % of the reference lines will
is advisable to check this point experimentally. For example,
not seriously distort bandwidth measurements. However, to
many instruments are operated with different slit programs in
accommodate the possible situation of sources with intensity
the ultraviolet and visible regions and thus exhibit different
relationships different from that encountered in this study,
signal-to-noise ratios in the two regions.
neighboring lines weaker than 15 % are tabulated in the
7.1.3 Set the period and signal-to-noise ratio to the values
seventh column under the heading “weak neighbor.”
used in 7.1.1 and 7.1.2, scan to the wavelength of interest (see
Table 1), and record the resulting mechanical slit widths or
7. Procedure
spectral bandwidth (Note 4).
7.1 Instruments with Servo-Operated Slits—These instru-
NOTE 4—It may be desirable to scan the entire wavelength range of the
ments maintain a constant period and signal-to-noise ratio as
instrument and record the slit width at suitable intervals so that a curve of
wavelength is automatically scanned. The determination of
slit width versus wavelength may be constructed (usually 25- and 50-nm
practical spectral bandwidth requires a preliminary determina-
intervals are satisfactory for the ultraviolet and visible regions, respec-
tion of the mechanical slit width necessary to yield a given tively).
E958
emitted by this lamp in this region. As slits are widened the continuum
7.1.4 Measure the spectral bandwidth of the instrument as
signalincreaseswiththesquareoftheslitwidth,whilethepeaklinesignal
follows:
increases linearly with slit width.
7.1.4.1 Position the appropriate line source so that it illumi-
The neighboring 302-nm line is clearly evident. It introduces a small
nates the entrance slit of the monochromator (Note 5). The
error into the measured spectral bandwidth when the spectral slit width
positioning
...

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5.2 This test method provides a means of determining the stray radiant power ratio of a spectrophotometer at selected wavelengths in a spectral range, as determined by the SRP filter used, thereby revealing those wavelength regions where significant photometric errors might occur. It does not provide a means of calculating corrections to indicated absorbance (or transmittance) values. The test method must be used with care and understanding, as erroneous results can occur, especially with respect to some modern grating instruments that incorporate moderately narrow bandpass SRP-blocking filters. This test method does not provide a basis for comparing the performance of different spectrophotometers.
Note 8: Kaye (3) discusses correction methods of measured transmittances (absorbances) that sometimes can be used if sufficient information on the properties and performance of the instrument can be acquired. See also A1.2.5.  
5.3 This test method describes the performance of a spectrophotometer in terms of the specific test parameters used. When an analytical sample is measured, absorption by the sample of radiation outside of the nominal bandpass at the analytical wavelength can cause a photometric error, underestimating the transmittance or overestimating the absorbance, and correspondingly underestimating the SRPR.  
5.4 The SRPR indicated by this test method using SRP filters is almost always an underestimation of the true value (see 1.3). A value cited in a manufacturer’s li...
SCOPE
1.1 Stray radiant power (SRP) can be a significant source of error in spectrophotometric measurements, and the danger that such error exists is enhanced because its presence often is not suspected (1-4).2 This test method affords an estimate of the relative radiant power, that is, the Stray Radiant Power Ratio (SRPR), at wavelengths remote from those of the nominal bandpass transmitted through the monochromator of an absorption spectrophotometer. Test-filter materials are described that discriminate between the desired wavelengths and those that contribute most to SRP for conventional commercial spectrophotometers used in the ultraviolet, the visible, the near infrared, and the mid-infrared ranges. These procedures apply to instruments of conventional design, with usual sources, detectors, including array detectors, and optical arrangements. The vacuum ultraviolet and the far infrared present special problems that are not discussed herein.
Note 1: Research (3) has shown that particular care must be exercised in testing grating spectrophotometers that use moderately narrow bandpass SRP-blocking filters. Accurate calibration of the wavelength scale is critical when testing such instruments. Refer to Practice E275.  
1.2 These procedures are neither all-inclusive nor infallible. Because of the nature of readily available filter materials, with a few exceptions, the procedures are insensitive to SRP of very short wavelengths in the ultraviolet, or of lower frequencies in the infrared. Sharp cutoff longpass filters are available for testing for shorter wavelength SRP in the visible and the near infrared, and sharp cutoff shortpass filters are available for testing at longer visible wavelengths. The procedures are not necessarily valid for “spike” SRP nor for “nearby SRP.” (See Annexes for general discussion and definitions of these terms.) However, they are adequate in most cases and for typical applications. They do cover...

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ASTM E275-08(2022)(Practice)
Standard Practice for Describing and Measuring Performance of Ultraviolet and Visible Spectrophotometers

SIGNIFICANCE AND USE
4.1 This practice permits an analyst to compare the general performance of an instrument, as it is being used in a specific spectrophotometric method, with the performance of instruments used in developing the method.
SCOPE
1.1 This practice covers the description of requirements of spectrophotometric performance, especially for test methods, and the testing of the adequacy of available equipment for a specific method (for example, qualification for a given application). The tests give a measurement of some of the important parameters controlling results obtained in spectrophotometric methods, but it is specifically not to be concluded that all the factors in instrument performance are measured, or in fact may be required for a given application.  
1.1.1 This practice is primarily directed to dispersive spectrophotometers used for transmittance measurements rather than instruments designed for diffuse transmission and diffuse reflection.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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ASTM E1421-99(2021)(Practice)
Standard Practice for Describing and Measuring Performance of Fourier Transform Mid-Infrared (FT-MIR) Spectrometers: Level Zero and Level One Tests

SIGNIFICANCE AND USE
4.1 This practice permits an analyst to compare the general performance of an instrument on any given day with the prior performance of an instrument. This practice is not necessarily meant for comparison of different instruments with each other even if the instruments are of the same type and model. This practice is not meant for comparison of the performance of one instrument operated under differing conditions.
SCOPE
1.1 This practice describes two levels of tests to measure the performance of laboratory Fourier transform mid-infrared (FT-MIR) spectrometers equipped with a standard sample holder used for transmission measurements.  
1.2 This practice is not directly applicable to Fourier transform infrared (FT-IR) spectrometers equipped with various specialized sampling accessories such as flow cells or reflectance optics, nor to Fourier transform near-infrared (FT-NIR) spectrometers, nor to FT-IR spectrometers run in step scan mode.  
1.2.1 If the specialized sampling accessory can be removed and replaced with a standard transmission sample holder, then this practice can be used. However, the user should recognize that the performance measured may not reflect that which is achieved when the specialized accessory is in use.  
1.2.2 If the specialized sampling accessory cannot be removed, then it may be possible to employ a modified version of this practice to measure spectrometer performance. The user is referred to Guide E1866 for a discussion of how these tests may be modified.  
1.2.3 Spectrometer performance tests for FT-NIR spectrometers are described in Practice E1944.  
1.2.4 Performance tests for dispersive MIR instruments are described in Practice E932.  
1.2.5 For FT-IR spectrometers run in a step scan mode, variations on this practice and information provided by the instrument vendor should be used.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3.1 Exception—Informational inch-pound units are provided in 5.4.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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ASTM E958-13(2021)(Practice)
Standard Practice for Estimation of the Spectral Bandwidth of Ultraviolet-Visible Spectrophotometers

SIGNIFICANCE AND USE
4.1 These practices should be used by a person who develops an analytical method to ensure that the spectral bandwidths cited in the practice are actually the ones used.
Note 2: The method developer should establish the spectral bandwidths that can be used to obtain satisfactory results.  
4.2 These practices should be used to determine whether a spectral bandwidth specified in a method can be realized with a given spectrophotometer and thus whether the instrument is suitable for use in this application. If accurate absorbance measurements are to be made on compounds with sharp absorption bands (natural half band widths of less than 15 nm) the spectral bandwidth of the spectrometer used should be better than 1/8th of the natural half band width of the compound’s absorption.  
4.3 These practices allow the user of a spectrophotometer to estimate the actual spectral bandwidth of the instrument under a given set of conditions and to compare the result to the spectral bandwidth calculated from data given in the manufacturer's literature or indicated by the instrument.
SCOPE
1.1 This practice describes procedures for estimating the spectral bandwidth of a spectrophotometer in the wavelength region of 185 nm to 820 nm.  
1.2 These practices are applicable to all modern spectrophotometer designs utilizing computer control and data handling. This includes conventional optical designs, where the sample is irradiated by monochromatic light, and ‘reverse’ optic designs coupled to photodiode arrays, where the light is separated by a polychromator after passing through the sample. For spectrophotometers that utilize servo-operated slits and maintain a constant period and a constant signal-to-noise ratio as the wavelength is automatically scanned, and/or utilize fixed slits and maintain a constant servo loop gain by automatically varying gain or dynode voltage, refer to the procedure described in Annex A1. This procedure is identical to that described in earlier versions of this practice.  
1.3 This practice does not cover the measurement of limiting spectral bandwidth, defined as the minimum spectral bandwidth achievable under optimum experimental conditions.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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ASTM E578-07(2021)(Test Method)
Standard Test Method for Linearity of Fluorescence Measuring Systems

SIGNIFICANCE AND USE
3.1 The range of concentration of a fluorescing substance in solution over which the fluorescence varies linearly with the concentration is the range most useful for quantitative analysis. This range is affected by properties of the solution under analysis and by features of the measuring system. This test method provides a means of testing the performance of a fluorescence measuring system and of determining the concentration range over which the system is suitable for making a given quantitative analysis.  
3.2 This test method is not meant for comparing the performance of different fluorescence measuring instruments.
SCOPE
1.1 This test method covers a procedure for evaluating the limits of the linearity of response with fluorescence intensity of fluorescence-measuring systems under operating conditions. Particular attention is given to slit widths, filters, and sample containers. This test method can be used to test the overall linearity under a wide variety of instrumental and sampling conditions. The results obtained apply only to the tested combination of slit width and filters, and the size, type and illumination of the sample cuvette, all of which must be stated in the report. The sources of nonlinearity may be the measuring electronics, excessive absorption of either the exciting or emitted radiation, or both, and the sample handling technique, particularly at low concentrations.  
1.2 This test method has been applied to fluorescence-measuring systems utilizing continuous and low-energy excitation sources (for example, an excitation source of 450 W electrical input or less). There is no assurance that extremely intense illumination will not cause photodecomposition of the compounds suggested in this test method.2 For this reason it is recommended that this test method not be indiscriminately employed with high-intensity light sources. It is not a test method to determine the linearity of response of other materials. If this test method is extended to employ other chemical substances, the principles within can be applied, but new material parameters, such as the concentration range of linearity, must be established. The user should be aware of the possibility that these other substances may undergo decomposition, or adsorption onto containers.  
1.3 This test method has been applied to fluorescence-measuring systems utilizing a single detector, that is, a photomultiplier tube or a single photodiode. It has not been demonstrated if this method is effective for photo-array instruments such as those using a CCD or a diode array detector.  
1.4 This test method is applicable to 10 mm pathlength cuvette formats and instruments covering a wavelength range within 190 nm to 900 nm. The use of other sample formats has not been established with this test method.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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ASTM E685-93(2021)(Practice)
Standard Practice for Testing Fixed-Wavelength Photometric Detectors Used in Liquid Chromatography

SIGNIFICANCE AND USE
4.1 Although it is possible to observe and measure each of the several characteristics of a detector under different and unique conditions, it is the intent of this practice that a complete set of detector specifications should be obtained under the same operating conditions. It should also be noted that to completely specify a detector’s capability, its performance should be measured at several sets of conditions within the useful range of the detector. The terms and tests described in this practice are sufficiently general that they may be used regardless of the ultimate operating parameters.  
4.2 Linearity and response time of the recorder or other readout device used should be such that they do not distort or otherwise interfere with the performance of the detector. This requires adjusting the gain, damping, and calibration in accordance with the manufacturer's directions. If additional electronic filters or amplifiers are used between the detector and the final readout device, their characteristics should also first be established.
SCOPE
1.1 This practice is intended to serve as a guide for the testing of the performance of a photometric detector (PD) used as the detection component of a liquid-chromatographic (LC) system operating at one or more fixed wavelengths in the range 210 nm to 800 nm. Measurements are made at 254 nm, if possible, and are optional at other wavelengths.  
1.2 This practice is intended to describe the performance of the detector both independently of the chromatographic system (static conditions) and with flowing solvent (dynamic conditions).  
1.3 For general liquid chromatographic procedures, consult Refs (1-9).2  
1.4 For general information concerning the principles, construction, operation, and evaluation of liquid-chromatography detectors, see Refs (10 and 11) in addition to the sections devoted to detectors in Refs (1-7).  
1.5 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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