Simultaneous determination of copper, zinc and lead by adsorptive stripping voltammetry in the presence of Morin

A sensitive and selective method for the simultaneous determination of copper, zinc and lead is presented. The method is based on the adsorptive accumulation of 2ʹ,3,4ʹ,5,7-pentahydroxyflavone (Morin) complexes of these elements onto a hanging mercury drop electrode, followed by reduction of adsorbed species by voltammetric scan using differential pulse modulation. Optimal analytical conditions were found to be Morin concentration of 2.0 (mu)M, pH of 4.0, and an adsorption potential at -500 mV versus Ag/AgCl. With an accumulation time of 60 s, the peak currents are proportional to the concentration of copper, lead and zinc over the 1 to 60, 0.3–80 and 1–70 ng ml^-1 range with detection limits of 0.06, 0.08 and 0.06 ng ml^-1, respectively. The procedure was applied to the simultaneous determination of copper, lead and zinc in some real and synthetic artificial real samples with satisfactory results.