Fig. 3

A) Cyclic voltammograms of 0.5 mM K₃[Fe(CN)₆] obtained with (a) bare SPE and (b) Bi₂O₃/CeO₂/SPE. B) Square Wave Anodic Stripping Voltammetry results for 45 µg/L of Cd(II) and Pb(II) in ABS (0.1 M, pH 4.5) recorded on (a) bare SPE and (b) Bi₂O₃/CeO₂/SPE. Deposition potential: -1.2 V; Deposition time: 160 s.