Personal air sampling for vapors of aniline compounds

A method has been developed for air sampling and laboratory analysis of vapors of seven aniline compounds: aniline, N,N-dimethylaniline, o-toluidine, 2,4-xylidine, panisidine, o-anisidine, and p-nitroaniline. Air is drawn by a personal sampling pump from a worker's breathing zone through a tube containing silica gel to collect any anilines present. In the laboratory each silica gel section is transferred to a glass-stoppered tube and desorbed with ethanol. An aliquot of this is analyzed by gas chromatography to determine the amount of each aniline compound present. The sampling tube can be used for short-term sampling at 1000 cm3/min or for sampling up to eight hours at 200 cm3/min. Maximum interference effects of water vapor have been considered. Results of retention, desorption, storage, accuracy, and precision studies are presented.