A Highly Sensitive Adsorptive Stripping Voltammetric Method for Simultaneous Determination of Lead and Vanadium in Foodstuffs

This work describes a procedure for the simultaneous determination of vanadium and lead in some food and water samples using adsorptive stripping voltammetric method. The method is based on the adsorptive accumulation of cupferron complexes of these elements onto hanging mercury drop electrode, followed by reduction of adsorbed species by voltammetric scan using differential pulse modulation. Optimal analytical conditions were found to be cupferron concentration of 8.00 × 10⁻⁵ M, pH of 4.8 (phosphate buffer), an accumulation potential at −100 mV, and a scan rate of 80 mV s⁻¹. With an accumulation time of 50 s, the peak currents proportional to the concentration of lead and vanadium over the 0.05–80.00 and 0.10–105.00 ng mL⁻¹ ranges with detection limit of 0.02 and 0.01 ng mL⁻¹, respectively. The procedure was applied to simultaneous determination of vanadium and lead in some food and water samples with satisfactory results.