Determination of trace amounts of uranium by stripping voltammetry using a boron-doped diamond electrode

Stripping voltammetry using a boron-doped diamond (BDD)-electrode is described for the determination of uranium. A uranium solution adjusted to pH 3 was supplied to the surface of an electrode continuously by a carrier solution at 0.10 mL min^-1, and uranium in the solution was accumulated. An accumulation potential of - 2.5 V (vs. Ag/AgCl) was applied to the BDD-electrode. After the accumulation step, the flow of the carrier solution was stopped and the stripping voltammogram, ranging from - 2.5 V to 1.0 V (vs. Ag/AgCl), was recorded. A linear relationship between the stripping peak current and the uranium concentration existed in the range from 0 to 1270 ng mL^-1, and the relative standard deviation of five repeated analyses was approximately 5% for 0.50 mL of an uranium standard solution of 127 ng mL^-1. The method was applied to the determination of uranium in low active liquid wastes from a spent nuclear-fuel reprocessing plant.