In World War II, the United States wanted its soldiers to be well-nourished, but scientists had no idea what vitamins were in foods, much less in what quantities. The government needed an inexpensive method for quickly and efficiently determining what vitamins were in foods. The new technique of UV spectroscopy offered promise, but instruments were expensive and had to be constructed by hand.
In 1941 the Beckman DU ultraviolet and visible (UV-vis) spectrophotometer was introduced, and determining the presence of
vitamins in food went from being an arduous ordeal to a quick, easy scan on the DU. The world of chemical instruments has
never been the same.
Introduction to UV-vis Spectroscopy
UV-vis spectroscopy probes the electronic transitions of molecules as they absorb light in the UV and visible regions of the electromagnetic spectrum. Any species with an extended system of alternating double and single bonds will absorb UV light, and anything with color absorbs visible light, making UV-vis spectroscopy applicable to a wide range of samples.
Sample
Spectrum: Benzene
A UV-vis spectrum of benzene is shown at left. The boom in ultraviolet spectroscopy began with vitamin A, but benzene is one of the most common chemicals that can be analyzed with UV-vis spectroscopy. In fact, a spectrum of benzene was included in the first article written about commercial UV-vis instruments. (Cary and Beckman, 1941)
Today, UV-vis spectroscopy is one of the truly routine techniques in modern biochemistry, biology, and pharmaceutical research.
Landmark Instrument: Beckman DU
With the introduction of the Beckman DU, optical instruments went from being specialized equipment to cheap and routinely used, changing the face of chemistry in the process.
Click here or the picture for more information about the history of the Beckman DU.
The Beckman DU was revolutionary because it took a very useful technique, UV-vis spectroscopy, and made it available in an instrument that was rugged, well-built, and self-contained.
Click here to learn how the Beckman DU works.
UV-vis spectroscopy is used every day in thousands of labs around the world. Modern UV-vis instruments are quite different than when the DU was introduced in 1941, but they all operate on the same basic principles.