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Instrument

Spectrophotometer

Physical Sciences

A spectrophotometer measures the intensity of light a sample transmits or reflects as a function of wavelength, comparing it against a reference to reveal how strongly the sample absorbs light at each wavelength, which in turn reveals what the sample contains and in what concentration. The chemist and instrument maker Arnold O. Beckman introduced the Beckman DU spectrophotometer in 1941, the first commercially viable instrument of its kind, and it became a standard fixture of analytical chemistry and biochemistry laboratories for decades.

Facts
Invented YearSourced to the subject's own account
1941 2
Measures
The amount of ultraviolet or visible light at discrete wavelengths that a sample absorbs or transmits, compared against a reference blank. 3
Operating Principle
Light from a source passes through a wavelength selector and then through the sample; a detector converts the transmitted light into an electronic signal that is processed into absorbance values revealing the sample's composition and concentration. 3
Operating Range
Roughly 100 to 780 nanometers overall, spanning the ultraviolet region (about 190 to 400 nanometers) and the visible region (about 380 to 780 nanometers). 3
Open Questions
Resolution
Not stated as a numeric figure in the cited source. 3
No resolution or precision value given.
Classification
Instrument Class
Spectroscopic Instrument 1
Connections

Anticipated By

Spectroscope, Instruments

Visual spectroscopy with the spectroscope preceded the added photometric measurement of the spectrophotometer.

Source Spectrophotometer (Britannica)

Invented By

Arnold Beckman, Scientists

The Beckman DU spectrophotometer, introduced in 1941, set the standard design for the instrument class.

Source Arnold Beckman (Wikipedia)

Used In

Chemistry, Disciplines
Source Spectrophotometer (Britannica)
Sources
1. Spectrophotometer (Britannica)
Encyclopaedia Britannica
  • Lede, instrument class
    A spectrophotometer measures the intensity of light a sample transmits or reflects as a function of wavelength, comparing it against a reference to reveal how strongly the sample absorbs light at each wavelength, which in turn reveals what the sample contains and in what concentration.
  • Used In: Chemistry
  • Anticipated By: Spectroscope
View the Source
2. Arnold Beckman (Wikipedia)
Wikipedia
  • Career section
    With Beckman's model D, later known as the DU spectrophotometer, National Technical Laboratories successfully provided the first easy-to-use single instrument containing both the optical and electronic components needed for ultraviolet-absorption spectrophotometry.
  • Invented By: Arnold Beckman
View the Source
3. UV-Vis Spectroscopy: Principles, Strengths and Applications (Technology Networks)
Technology NetworksArticle introduction (UV-Vis wavelength range discussion)
Quote, Article introduction (UV-Vis wavelength range discussion)
From approximately 100 nm...780 nm
View the Source

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