The simultaneous determination of chloroformates and phosgene at low concentrations in air using a solid sorbent sampling--gas chromatographic procedure

A method was developed for the simultaneous determination of a number of reactive chloroformates and phosgene in air at low concentration levels. The procedure utilized the collection of air containing these contaminants on a di-n-butylamine-coated solid adsorbent. After samples were taken, the carbamate and urea derivatives were desorbed with hexane, washed with 1N HCl and analyzed by gas chromatography with flame ionization detection. The procedure provided an accurate exposure level for each of the desired compounds on a time-weighted average basis. Average recovery efficiencies ranged from 98% to 106%, with an average detection limit of 0.7 micrograms or 0.08 ppm v/v in 1.5 L of air. More recent tests have extended the use of the technique to include carboxylic acid chlorides--specifically, pivalic acid chloride and 3-chloropivalic acid chloride. The average recovery efficiency for these compounds was 69%.