Application of a solid lead microelectrode as a new voltammetric sensor for adsorptive stripping voltammetry of U(VI)

For the first time solid lead microelectrode was utilized for analytical purposes: the article reports on its application for adsorptive stripping voltammetric determination of U(VI) ions. The proposed solid metal microelectrode of a diameter of 25 μm contains about 30 μg of metallic lead that significantly restricts amount of toxic lead introduced into the environment in comparison to lead film equivalents. The potential window of the proposed sensor was checked by means of cyclic voltammetry. The optimization of the analytical procedure of determination of U(VI) ions complexed with cupferron was performed. The experimental parameters (potential of microelectrode activation, pH of supporting electrolyte, complexing agent concentration, potential and time of accumulation and effects of possible interferences) were studied. A linear calibration graph for U(VI) determination was linear in the range from 2 × 10^-9 to 1 × 10^-7 mol L^-1 (accumulation time of 120 s). The obtained detection limit for uranium ions determination following accumulation time of 120 s was 5.5 × 10^-10 mol L^-1. Repeatability of the method calculated as RSD % for U(VI) concentration of 2 × 10^-8 mol L^-1 was 4.7% (n = 5). The proposed procedure was successfully applied for U(VI) ions determination in lake water certified reference material that confirms analytical application.