An adsorptive stripping voltammetry procedure for ultra-trace determination of U(VI) using double accumulation step on two lead-film working electrodes

We report a very sensitive stripping voltammetric procedure for determination of ultra-trace quantity of U(VI) in water samples. A very low detection limit was achieved owing to the application of a new construction of the voltammetric electrode cell with two built-in working electrodes that differed significantly in their surface area. The procedure was based on the double adsorptive accumulation of the U(VI)-cupferron complex onto two lead film working electrodes. Under optimal conditions the detection limit for accumulation time of 120 s for the big electrode and 120 s for the small electrode was about 3.1×10–11 mol L−1, whereas for accumulation time of 480 s for the big electrode and 240 s for the small electrode it was about 1.1×10–11 mol L−1. The proposed method was successfully validated using certified reference material seawater NASS-5.