EXTRACTION, CLEANUP AND DETERMINATION OF IONIC ALKYLLEAD COMPOUNDS IN ROAD DUST BY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

An experimental study of the dean-up before and after derivatization with BuMgCl in the determination of Me(3)Pb+, Et(3)Pb+ 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. Me(3)BuPb, Et(3)BuPb and Bu(4)Pb 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 Me(3)Pb+ was obtained using a road dust sample.