Abstract
A rapid and simple method for the determination of small amounts of phosphine in air by detector tubes was investigated. For the rapid determination, several detector reagents showing discoloration when exposed to air containing small amounts of phosphine were studied, among which silica gel added with gold chlo ride was the most suitable. The concentration of phosphine was estimated by measuring the length of discolored zone after drawing definite volumes of air sample (100 ml, 500 ml, and 5 l) through the tube with a constant flow rate (1 ml/sec). The measurable concentration range by this method was 0.03150 ppm of phosphine. The relative error was within ±5%. Effects of water content of the detector reagent, the volume of sample, temperature of the detector tube, feeding time, etc., and influences of the other gases were tested. The method gave results generally agreeable with colorimetric analysis, and was recommended as a field method.
