The Ultraviolet Method of Continuous Gas Analysis

Abstract

Ultraviolet radiation absorption measurement has been used for some time for the determination of the concentrations of absorbing gases. Instruments have been constructed for spot reading or continuous recording of the concentration of one component of a mixture. Only a few instruments are commercially available for continuous analysis of atmospheric contamination in order to control noxious or explosive vapors, and for analysis and control of chemical process streams. Widespread use of continuous ultraviolet gas analyzers will not come until certain difficult problems are solved. These problems are: (a) high sensitivity to small absorptions must be achieved as well as long‐ and short‐time stability of a high degree; (b) the interference due to sample gas components that absorb ultraviolet radiation, in addition to the component, whose concentration it is desired to determine, introduces inaccuracies; and (c) the presence of dust, condensables, and corrosive materials in the sample gas and in the ambient air reduces the accuracy and mechanical reliability of the analyzer.

Ultraviolet Absorption Spectroscopy

“…Barer, Holiday, and Jope (5) used a combination of the Burch reflecting microscope and a quartz spectrograph to study the variation of ultraviolet absorption with location in a single living cell at a series of wave lengths. A review of gas analyzers utilizing ultraviolet absorption is given by Glasser (21). Caster (13) discusses in some detail the instrumental factors which limit the accuracy and precision of data obtained with the Beckman spectrophotometer.…”