DETECTION OF SMALL QUANTITIES OF PHOTOCHEMICALLY PRODUCED OXYGEN BY REACTION WITH ALKALINE PYROGALLOL

A procedure is described for quantitative estimation of small amounts of oxygen produced by photochemical reaction. The procedure involves continuous removal of evolved oxygen In a stream of carrier gas to avoid inhibitory side reactions and subsequent chemical trapping of the oxygen with alkaline pyrogallol. The concentration of oxygen can be measured Indirectly by absorption spectrometry of the highly colored oxidation product of pyrogallol. The reagent solution is stable over the experimental time scale and the change in absorbance at 450 nm gives a good measure of the concentration of oxygen present In the solution. Under the experimental conditions, the minimum amount of oxygen that can be detected Is 3.5 X 10-7 mol which corresponds to a minimum quantum yield for oxygen production of 1X10-3. © 1979, American Chemical Society. All rights reserved.