A Novel Eco-Friendly and Highly Sensitive Solid Lead-Tin Microelectrode for Trace U(VI) Determination in Natural Water Samples.

For the first time a solid state lead-tin microelectrode (diameter ϕ 25 µm) was utilized for U(VI) ion determination by adsorptive stripping voltammetry. The described sensor is characterized by high durability, reusability and eco-friendly features, as the need for using lead and tin ions for metal film preplating has been eliminated, and consequently, the amount of toxic waste has been limited. The advantages of the developed procedure resulted also from the utilization of a microelectrode as a working electrode, because a restricted amount of metals is needed for its construction. Moreover, field analysis is possible to perform thanks to the fact that measurements can be carried out from unmixed solutions. The analytical procedure was optimized. The proposed procedure is characterized by two orders of magnitude linear dynamic range of U(VI) determination from 1 × 10 to 1 × 10 mol L (120 s of accumulation). The detection limit was calculated to be 3.9 × 10 mol L (accumulation time of 120 s). RSD% calculated from seven subsequent U(VI) determinations at a concentration of 2 × 10 mol L was 3.5%. The correctness of the analytical procedure was confirmed by analyzing a natural certified reference material.