AbstractA photometric procedure based on the reaction between bromides and sodium gold chloride has been developed as another means of determining the bromide formed in the determination of fumigants, such as methyl bromide, and ethylene dibromide, by catalytic oxidation of the gas and its subsequent absorption in an alkaline solution containing hydrogen peroxide. The method is applicable to solutions containing 0.1–4.0 mg. of inorganic bromide in a volume of 8 ml. Extinctions are measured by means of a Spekker photoelectric absorptiometer. Results obtained in a series of experiments with ethylene dibromide are given, and compared with a similar series in which the bromide formed was determined by potentiometric titration with silver nitrate.