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204.1 - Molecular Absorption (film, filter, solid, and solution forms)

204.1 - Molecular Absorption (film, filter, solid, and solution forms) The optical SRMs for spectrophotometry are certified transfer standards that fall into three general categories: transmittance, wavelength, and stray radiant energy; each of which addresses a specific instrumental parameter of an absorption spectrometer that must be in control for accurate optical transmittance measurements. To obtain optimum verification results, each SRM must be used within the specified range of conditions for which it is intended.

SRM 2009a Didymium Wavelength: SRM 2009a is now being supported by Calibration Service (Service No. 38061S). Click here for the NIST Calibrations web site: http://www.nist.gov/calibrations. SRM 2035a is an alternative.

SRM 2065 has been replaced by SRM 2035b.

For further information on filters are available:

SP 260-54 - Certification and Use of Acidic Potassium Dichromate Solutions as an Ultraviolet Absorbance Standard SRM 935 (August 1977).

SP 260-68 - Metal-On- Quartz Filters as a Standard Reference Material for Spectrophotometry SRM 2031 (April 1980).

Also see: Table 204.2 - Optical Properties

PLEASE NOTE: The tables are presented to facilitate comparisons among a family of materials to help customers select the best SRM for their needs. For specific values and uncertainties, the certificate is the only official source.


- Certified values are normal font
- Reference values are italicized
- Values in parentheses are for information only


Detail - Detail    Certificate - Certificate    Report of Investigation - Report of Investigation    MSDS - MSDS    Data Files - Data Files    Questionaire - Questionnaire


  SRM Description Unit Size     Parameter
Detail Certificate MSDS 931h
Now Selling
Liquid Absorbance Standard for Ultraviolet and Visible Spectrophotometry set (12)   absorbance standard
Detail Certificate MSDS 935a
Out of Stock
Potassium Dichromate (Ultraviolet Absorbance Standard)
15 g   235 to 350
Detail Certificate MSDS 1921b
Now Selling
Infrared Transmission Wavelength/Wavenumber Standard
1 card   3 µm to 18 µm
Detail Certificate MSDS Data Files 1928
Now Selling
Infrared Specular High Reflectance Standard (Nominal Diameter 51 mm) disk   gold plated copper disk, 9.0 mm thick and 50.8 mm in diameter
Detail Certificate MSDS Data Files 1929
Now Selling
Infrared Specular High Reflectance Standard (Nominal Diameter 25 mm) disk   gold plated copper disk, 3.0 mm thick and 25.3 mm in diameter
Detail Certificate MSDS Data Files 2031c
Now Selling
Metal-on-Fused-Silica Neutral Density Filters (250 nm to 635 nm) set (3)   250 nm to 635 nm
Detail Certificate MSDS Data Files 2034
Now Selling
Holmium Oxide Solution Wavelength Standard (240 nm to 650 nm) Cuvette   250 nm to 650 nm
Detail Certificate MSDS 2035b
Now Selling
Ultraviolet-Visible-Near-Infrared Wavelength/Wavenumber Transmission Standard each   UV-Vis peak locations between 334 nm and 804 nm
NIR band locations between 975 nm and 1945 nm
Detail Certificate MSDS 2036
Now Selling
Near Infrared Wavelength/Wavenumber Reflection Standard
each   975 nm to 1946 nm
Detail Certificate MSDS Data Files 2082
Out of Stock
Pathlength Absorbance Standards for Microliter Volume Spectrophotometers set of 3 vials   pathlength absorbance