Abstract
A method for sensitive determination of aromatic carboxylic acids in airborne particulates is described. Airborne particulates are collected on silica fiber filters with a high volume air sampler. Aromatic carboxylic acids in the samples are extracted with 0.2mol dm-3 sodium hydroxide by heating at 70°C. The carboxylic acids are derivatized with pentafluorobenzyl bromide, and cleaned up through a Sep-Pak NH2 cartridge. The resulting derivatives are determined sensitively and selectively with a gas chromatograph equipped with an electron capture detector. The detection limit is 0.02μg for o-, m- and p- toluic acids, and 0.03μg for benzoic acid.
