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ASTM E958-13

(Practice)

Standard Practice for Estimation of the Spectral Bandwidth of Ultraviolet-Visible Spectrophotometers

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 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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

Status
Historical
Publication Date
31-Dec-2012
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
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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 − 13
Standard Practice for
Estimation of the Spectral Bandwidth of Ultraviolet-Visible
1
Spectrophotometers
This standard is issued under the fixed designation E958; 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.
1. Scope 3. Summary of Practice
1.1 This practice describes procedures for estimating the
3.1 The following test procedures are written for all spec-
spectral bandwidth of a spectrophotometer in the wavelength
trophotometer designs that have provision for recording (that
region of 185 to 820 nm.
is, collecting and storing) spectral data digitally. Processing
may be by built-in programs or in a separate computer. Data
1.2 These practices are applicable to all modern spectropho-
may be collected in either the transmittance or the absorbance
tometer designs utilizing computer control and data handling.
mode, although for the Liquid Ratio procedure, the peak and
Thisincludesconventionalopticaldesigns,wherethesampleis
trough values must be measured in absorbance.
irradiated by monochromatic light, and ‘reverse’optic designs
coupled to photodiode arrays, where the light is separated by a
3.2 Line Emission Source Procedure—The continuum
polychromator after passing through the sample. For spectro-
source is replaced with a line emission source, such as a
photometers that utilize servo-operated slits and maintain a
mercury lamp, and the apparent half-intensity bandwidth of an
constant period and a constant signal-to-noise ratio as the
emission line occurring in the wavelength region of interest is
wavelength is automatically scanned, and/or utilize fixed slits
measured using the slit width, or indicated spectral bandwidth
and maintain a constant servo loop gain by automatically
required to be estimated. This procedure can be used for
varying gain or dynode voltage, refer to the procedure de-
instrumentation having spectral bandwidths in the range 0.1 to
scribed in Annex A1. This procedure is identical to that
10 nm.
described in earlier versions of this practice.
NOTE 1—In photodiode array instrumentation, the array spacing be-
1.3 This practice does not cover the measurement of limit-
tween the diode elements may invalidate this procedure.
ing spectral bandwidth, defined as the minimum spectral
3.3 Liquid Ratio Procedure—The calculated spectral peak
bandwidth achievable under optimum experimental conditions.
to trough ratio of a defined small percentage of toluene in
1.4 The values stated in SI units are to be regarded as
hexane will vary with the spectral bandwidth of the spectro-
standard. No other units of measurement are included in this photometer when scanned in the UV region. This procedure
standard.
can be used for all instrumentation having spectral bandwidths
in the range 0.5 to 3.0 nm.
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.4 Benzene Vapor Procedure—The characteristics of a
responsibility of the user of this standard to establish appro-
spectrum of benzene vapor in the UV region will vary
priate safety and health practices and determine the applica-
significantlywiththespectralbandwidthofthespectrophotom-
bility of regulatory limitations prior to use.
eter. This procedure can be used for instrumentation having
spectral bandwidths in the range 0.1 to 0.5 nm.
2. Terminology
2.1 Definitions: 4. Significance and Use
2.1.1 spectral bandwidth, n—the wavelength interval of
4.1 These practices should be used by a person who
radiation leaving the exit slit of a monochromator measured at
develops an analytical method to ensure that the spectral
half the peak detected radiant power.
bandwidths cited in the practice are actually the ones used.
NOTE 2—The method developer should establish the spectral band-
widths that can be used to obtain satisfactory results.
1
This practice is under the jurisdiction of ASTM Committee E13 on Molecular
Spectroscopy and Separation Science and is the direct responsibility of Subcom-
4.2 These practices should be used to determine whether a
mittee E13.01 on Ultra-Violet, Visible, and Luminescence Spectroscopy.
spectral bandwidth specified in a method can be realized with
Current edition approved Jan. 1, 2013. Published February 2013. Originally
a given spectrophotometer and thus whether the instrument is
approved in 1983. Last previous edition approved in 2005 as E958 – 93 (2005).
DOI: 10.1520/E0958-13. suitable for use in this application. If accurate absorbance
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
...

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: E958 − 93 (Reapproved 2005) E958 − 13
Standard Practice for
Measuring Practical Estimation of the Spectral Bandwidth of
1
Ultraviolet-Visible Spectrophotometers
This standard is issued under the fixed designation E958; 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.
1. Scope
1.1 This practice describes a procedure procedures for measuringestimating the practical spectral bandwidth of a spectropho-
tometer 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 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. It is also applicable to instruments that scanned, and/or utilize
fixed slits and maintain a constant servo loop gain by automatically varying gain or dynode voltage. In this latter case, the
signal-to-noisevoltage, refer to the procedure described in Annex A1ratio 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. 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 and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
E131 Terminology Relating to Molecular Spectroscopy
E275 Practice for Describing and Measuring Performance of Ultraviolet and Visible Spectrophotometers
2. Terminology
2.1 Definitions:
3.1.1 integration period, n—the time, in seconds, required for the pen or other indicator to move 98.6 % of its maximum travel
in response to a step function.
3.1.2 practical spectral bandwidth, designated by the symbol:
π
Δλ (1)
~ !
S/N
where:
Δλ = spectral bandwidth,
π = integration period, and
S/N = signal-to-noise ratio measured at or near 100 % T.
1
This practice is under the jurisdiction of ASTM Committee E13 on Molecular Spectroscopy and Separation Science and is the direct responsibility of Subcommittee
E13.01 on Ultra-Violet, Visible, and Luminescence Spectroscopy.
Current edition approved April 1, 2005Jan. 1, 2013. Published April 2005February 2013. Originally approved in 1983. Last previous edition approved in 19992005 as
E958 – 93 (1999).(2005). DOI: 10.1520/E0958-93R05.10.1520/E0958-13.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E958 − 13
3.1.3 signal-to-noise ratio, n—the ratio of the signal, S, to the noise, N, as indicated by the readout indicator. The recommended
measure of noise is the maximum peak-to-peak excursion of the indicator averaged over a series of five successive intervals, each
of duration ten times the integration period. (This measure of noise is about five times the root-mean-square noise.)
2.1.1 spectral bandwidth, n—the wavelength interval of radiation leaving the exit slit of a monochromator measured at half the
peak detected radiant power. It is not synonymous with spectral slit width, which is the product of the mechanical slit width and
the reciprocal linear dispersion of the spectrophotometer.
3. Summary of Practice
3.1 The follo
...

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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
ASTM E1982-98(2021)(Practice)
Standard Practice for Open-Path Fourier Transform Infrared (OP/FT-IR) Monitoring of Gases and Vapors in Air

SIGNIFICANCE AND USE
4.1 An OP/FT-IR monitor can, in principle, measure the concentrations of all IR-active gases and vapors in the atmosphere. Detailed descriptions of OP/FT-IR systems and the fundamental aspects of their operation are given in Practice E1685 and the FT-IR Open-Path Monitoring Guidance Document. A method for processing OP/FT-IR data to obtain the concentrations of gases over a long, open path is given in Compendium Method TO-16. Applications of OP/FT-IR systems include monitoring for gases and vapors in ambient air, along the perimeter of an industrial facility, at hazardous waste sites and landfills, in response to accidental chemical spills or releases, and in workplace environments.
SCOPE
1.1 This practice covers procedures for using active open-path Fourier transform infrared (OP/FT-IR) monitors to measure the concentrations of gases and vapors in air. Procedures for choosing the instrumental parameters, initially operating the instrument, addressing logistical concerns, making ancillary measurements, selecting the monitoring path, acquiring data, analyzing the data, and performing quality control on the data are given. Because the logistics and data quality objectives of each OP/FT-IR monitoring program will be unique, standardized procedures for measuring the concentrations of specific gases are not explicitly set forth in this practice. Instead, general procedures that are applicable to all IR-active gases and vapors are described. These procedures can be used to develop standard operating procedures for specific OP/FT-IR monitoring applications.  
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 practice 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 practice 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
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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