Square wave anodic stripping voltammetry (SWASV) was applied to the simultaneous determination of trace amounts of toxic metals Pb(II), Cd(II) and Cu(II) in white poplar (populus) leaves, used as bio indicator and gathered in a chosen area of the city of Lisbon with very high traffic intensity. The leaves were dried and subsequently exposed to an acid digestion microwave process. Square wave parameters were optimized for the voltammetric analysis of the samples. The working electrode consisted of a thin mercury film (TMFE) deposited on the surface of vitreous carbon. The pair Ag/AgCl was used as the reference electrode and a Pt wire as the auxiliary electrode. Average concentrations (in mg of metal/kg of dry matter-leaves) of 2.6, 0.18, and 5.0 were obtained for Pb(II), Cd(II) and Cu(II), respectively. The value for lead coincides with the one obtained by the reference method based on Graphite Furnace Atomic Absorption Spectrophotometry (GFAAS).
SWASV; environmental samples; toxic metals; microwave digestion; bio indicator
