Screen-printed carbon electrodes (SPCEs) and carbon paste electrodes (CPEs) were prepared as “mercury-free” electrochemical sensors for the determination of trace metal ions in aqueous solutions. SPCEs were coated with conducting polymer layers of either polyaniline (PANI), or polyaniline-poly(2,2′–dithiodianiline) (PANI-PDTDA). Furthermore, CPEs containing electroactive compounds with reactivity towards metal ions were employed to obtain enhanced selectivity. Optimised experimental conditions for Hg 2+ , Pb 2+ , Ni 2+ and Cd 2+ determination included the supporting electrolyte concentration, deposition potential (E d ) and accumulation time (t acc ). Initial results showed linearity in the examined concentration range between 1 × 10 -9 M and 1 × 10 -6 M for laboratory prepared solutions