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Perkin-Elmer Model 21 Infrared Spectrophotometer

  • After 1950
  • Manufactured by Perkin-Elmer Corporation
    Made in Norwalk, CT
  • 21.375 in. H x 39.5 in. W x 16 in. D
    Coated metal, aluminum, plastic, paper, rubber, glass
  • On display in Making Modernity
  • Gift of Mr. Vincent J. Coates
  • 2003.031A-D


The Perkin-Elmer Model 21 was designed as the first linear wave-number versus transmittance recording spectrophotometer. This particular instrument was built in 1952 at the original Perkin-Elmer factory in Glenbrook, Connecticut, and was purchased by the American Cyanamid Company in Stamford, Connecticut, in 1952.

Spectrophotometers determine the composition of a solution (or the concentration of certain substances within a solution) by measuring how the solution absorbs a particular wavelength of light. By varying the wavelengths in each measurement, one can take a spectrum of a solution and ascertain the composition. More advanced spectrophotometers can measure beyond the visible spectrum, providing readings for ultraviolet and infrared wavelengths.

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Of Related Interest

Arnold O. Beckman

CHF’s Beckman Center for the History of Chemistry was started with a generous grant from the Arnold and Mabel Beckman Foundation in 1987.



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