A METHOD FOR THE DETERMINATION OF LOW CONCENTRATIONS OF ORGANIC VAPOURS IN AIR AND EXHALED BREATH

Abstract

A method is described for the determination of low concentrations of organic vapours in air and in exhaled breath. A measured volume is sampled through a tube containing silica gel, then the vapour is desorbed with water in a closed tube and a sample of the head space air is taken for analysis by gas-liquid chromatography. The sensitivity and application of the method depends mainly on the efficiency of adsorption on silica gel, the air-water partition coefficient and the detector response. The limit of sensitivity and maximal loading on the silica gel have been determined for benzene, n-butanol, acetone, hexane and trichloroethylene. Examples are given of the determination of benzene, acetone and trichloroethylene in street air and in the breath of non-occupationally exposed individuals.