Extraction, clean-up and determination of ionic alkyllead compounds in road dust by gas chromatography–mass spectrometry

Abstract

An experimental study of the clean-up before and after derivatization with BuMgCl in the determination of Me₃Pb⁺, Et₃Pb⁺ and Pb²⁺ in road dust is described. The analytical procedure consisted of an extraction at pH 9.0 (buffer) of the diethyldithiocarbamate complex in pentane followed by the evaporation to dryness and derivatization in hexane with BuMgCl. Me₃BuPb, Et₃BuPb and Bu₄Pb are separated and quantified by gas chromatography–mass spectrometry in the selected ion monitoring mode. The adsorbents Florisil, Silicagel, alumina, Amberlite (XAD-2 and XAD-7) and Chromosorb with 3% and 10% deactivation degree were investigated for the clean-up. Prior to derivatization, Florisil, Silicagel and Alumina retained all the diethyldithiocarbamate complexes. The Amberlites (XAD-2 and XAD-7) and Chromosorb did not trap either diethyldithiocarbamate complexes or other interference compounds. After derivatization, alumina was to be the most effective adsorbent. Under these conditions, a recovery of 86.5% of Me₃Pb⁺ was obtained using a road dust sample.