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

An experimental study of the dean-up before and after derivatization w ith BuMgCl in the determination of Me(3)Pb+, Et(3)Pb+ and Pb2+ in road dust is described. The analytical procedure consisted of an extractio n at pH 9.0 (buffer) of the diethyldithiocarbamate complex in pentane followed by the evaporation to dryness and derivatization in hexane wi th BuMgCl. Me(3)BuPb, Et(3)BuPb and Bu(4)Pb are separated and quantifi ed by gas chromatography-mass spectrometry in the selected ion monitor ing mode. The adsorbents Florisil, Silicagel, alumina, Amberlite (XAD- 2 and XAD-7) and Chromosorb with 3% and 10% deactivation degree were i nvestigated for the clean-up. Prior to derivatization, Florisil, Silic agel and Alumina retained all the diethyldithiocarbamate complexes. Th e Amberlites (XAD-2 and XAD-7) and Chromosorb did not trap either diet hyldithiocarbamate complexes or other interference compounds. After de rivatization, alumina was to be the most effective adsorbent. Under th ese conditions, a recovery of 86.5% of Me(3)Pb+ was obtained using a r oad dust sample.