Detector for phosphine at permissible levels in air

Abstract

A paper-strip detector has been developed for detecting maximum acceptable concentrations (0.05-0.3 p.p.m.) of phosphine in air. The strips are prepared by dipping them in a 1% solution of mercuric chloride in methyl yellow, and phosphine turns them red. Ammonia interferes with the proper development of the colour. The strips are useful for personal protection against phosphine in fumigation and degassing operations and also to detect traces of phosphine in fumigated commodities.