Zinc, cadmium, lead and copper: Electrolyte: Acetate buffer, pH = 4.6 with CH3COOH, NH3 and HCl. AE: Pt RE: Ag/AgCl/KCl 3M Parameters: Zn at the SMDE, Ustart = -800 mV, Uend = -1200 mV Cd, Pb and Cu at the HMDE, DPASV (+50 mV) Umeas = -700 mV (90s), Ustart = -700 mV, Uend = +30 mV Ep (Zn) = -960 mV, Ep (Cd) = -600 mV Ep (Pb) = -380 mV, Ep (Cu) = -120 mV