ASTM E2911-23
(Guide)Standard Guide for Relative Intensity Correction of Raman Spectrometers
Standard Guide for Relative Intensity Correction of Raman Spectrometers
SIGNIFICANCE AND USE
4.1 Generally, Raman spectra measured using grating-based dispersive or Fourier transform Raman spectrometers have not been corrected for the instrumental response (spectral responsivity of the detection system). Raman spectra obtained with different instruments may show significant variations in the measured relative peak intensities of a sample compound. This is mainly as a result of differences in their wavelength-dependent optical transmission and detector efficiencies. These variations can be particularly large when widely different laser excitation wavelengths are used, but can occur when the same laser excitation is used and spectra of the same compound are compared between instruments. This is illustrated in Fig. 1, which shows the uncorrected luminescence spectrum of SRM 2241, acquired upon four different commercially available Raman spectrometers operating with 785 nm laser excitation. Instrumental response variations can also occur on the same instrument after a component change or service work has been performed. Each spectrometer, due to its unique combination of filters, grating, collection optics and detector response, has a very unique spectral response. The spectrometer dependent spectral response will of course also affect the shape of Raman spectra acquired upon these systems. The shape of this response is not to be construed as either “good or bad” but is the result of design considerations by the spectrometer manufacturer. For instance, as shown in Fig. 1, spectral coverage can vary considerably between spectrometer systems. This is typically a deliberate tradeoff in spectrometer design, where spectral coverage is sacrificed for enhanced spectral resolution.
FIG. 1 SRM 2241 Measured on Four Commercial Raman Spectrometers Utilizing 785 nm Excitation
4.2 Variations in spectral peak intensities can be mostly corrected through calibration of the Raman intensity (y) axis. The conventional method of calibration of the spectral response of a Raman...
SCOPE
1.1 This guide is designed to enable the user to correct a Raman spectrometer for its relative spectral-intensity response function using NIST Standard Reference Materials2 in the 224X series (currently SRMs 2241, 2242, 2243, 2244, 2245, 2246), or a calibrated irradiance source. This relative intensity correction procedure will enable the intercomparison of Raman spectra acquired from differing instruments, excitation wavelengths, and laboratories.
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 Because of the significant dangers associated with the use of lasers, ANSI Z136.1 or suitable regional standards should be followed in conjunction with this practice.
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.
General Information
Standards Content (Sample)
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.
Designation: E2911 − 23
Standard Guide for
1
Relative Intensity Correction of Raman Spectrometers
This standard is issued under the fixed designation E2911; 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 E2529 Guide for Testing the Resolution of a Raman Spec-
trometer
1.1 This guide is designed to enable the user to correct a
4
2.2 ANSI Standard:
Raman spectrometer for its relative spectral-intensity response
2
Z136.1 Safe Use of Lasers
function using NIST Standard Reference Materials in the
224X series (currently SRMs 2241, 2242, 2243, 2244, 2245,
3. Terminology
2246), or a calibrated irradiance source. This relative intensity
3.1 Definitions—Terminology used in this practice con-
correction procedure will enable the intercomparison of Raman
spectra acquired from differing instruments, excitation forms to the definitions in Terminology E131.
wavelengths, and laboratories.
4. Significance and Use
1.2 The values stated in SI units are to be regarded as
4.1 Generally, Raman spectra measured using grating-based
standard. No other units of measurement are included in this
dispersive or Fourier transform Raman spectrometers have not
standard.
been corrected for the instrumental response (spectral respon-
1.3 Because of the significant dangers associated with the
sivity of the detection system). Raman spectra obtained with
use of lasers, ANSI Z136.1 or suitable regional standards
different instruments may show significant variations in the
should be followed in conjunction with this practice.
measured relative peak intensities of a sample compound. This
1.4 This standard does not purport to address all of the
is mainly as a result of differences in their wavelength-
safety concerns, if any, associated with its use. It is the
dependent optical transmission and detector efficiencies. These
responsibility of the user of this standard to establish appro-
variations can be particularly large when widely different laser
priate safety, health, and environmental practices and deter-
excitation wavelengths are used, but can occur when the same
mine the applicability of regulatory limitations prior to use.
laser excitation is used and spectra of the same compound are
1.5 This international standard was developed in accor-
compared between instruments. This is illustrated in Fig. 1,
dance with internationally recognized principles on standard-
which shows the uncorrected luminescence spectrum of SRM
ization established in the Decision on Principles for the
2241, acquired upon four different commercially available
Development of International Standards, Guides and Recom-
Raman spectrometers operating with 785 nm laser excitation.
mendations issued by the World Trade Organization Technical
Instrumental response variations can also occur on the same
Barriers to Trade (TBT) Committee.
instrument after a component change or service work has been
performed. Each spectrometer, due to its unique combination
2. Referenced Documents
of filters, grating, collection optics and detector response, has a
3
2.1 ASTM Standards:
very unique spectral response. The spectrometer dependent
E131 Terminology Relating to Molecular Spectroscopy
spectral response will of course also affect the shape of Raman
E1840 Guide for Raman Shift Standards for Spectrometer
spectra acquired upon these systems. The shape of this re-
Calibration
sponse is not to be construed as either “good or bad” but is the
result of design considerations by the spectrometer manufac-
turer. For instance, as shown in Fig. 1, spectral coverage can
1
This guide is under the jurisdiction of ASTM Committee E13 on Molecular
Spectroscopy and Separation Science and is the direct responsibility of Subcom- vary considerably between spectrometer systems. This is
mittee E13.08 on Raman Spectroscopy.
typically a deliberate tradeoff in spectrometer design, where
Current edition approved April 1, 2023. Published May 2023. Originally
spectral coverage is sacrificed for enhanced spectral resolution.
approved in 2013. Last previous edition approved in 2013 as E2911 – 13 which was
withdrawn July 2022 and reinstated in April 2023. DOI: 10.1520/E2911–23.
4.2 Variations in spectral peak intensities can be mostly
2
Trademark of and available from NIST Office of Reference Materials, 100
corrected through calibration of the Raman intensity (y) axis.
Bureau Drive, Stop 2300, Gaithersburg, MD 20899-2300. http://www.nist.gov/srm.
3
For refe
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