Development simple and sensitive voltammetric procedure for ultra-trace determination of U(VI)

A simple and sensitive adsorptive stripping voltammetric procedure for the determination of trace concentration of U(VI) in natural water samples was developed. In order to remove surface active compounds from water sample solutions, a TiO₂/Al₂O₃ photocatalysis system was applied. The linear calibration graph of U(VI) in the simultaneous presence of 2mgL^-1 anionic, cationic and nonionic surfactants, in the range from 5×10^-10 to 2×10^-8molL^-1 (180s) was achieved. The detection limit obtained in the solution after the use of UV-irradiation (10min) with TiO₂/Al₂O₃ photocatalyst (0.9g) is equal to 2.3×10^-10mol L^-1. The presented procedure was successfully applied to uranium determination in SLEW-3 certified reference material, and to river water samples. In addition, a very low detection limit (2.9×10^-11molL^-1) for accumulation time of 180s was achieved due to application of a reversible deposited mediator (Zn) in the step of lead film electrode preparation.