Adsorptive stripping voltammetric determination of trace uranium with a bismuth-film electrode based on the U(VI) -> U(V) reduction step of the uranium-cupferron complex

摘要

This work reports the use of adsorptive stripping voltammetry (AdSV) for the determination of uranium on a preplated rotating-disk bismuth-film electrode (BiFE). ne principle of the method relied on the complexation of U(VI) ions with cupferron and the subsequent adsorptive accumulation of the complex on the surface of the BiFE. The uranium in the accumulated complex was then reduced by means of a cathodic voltammetric scan while the analytically useful U(VI) -> U(V) reduction signal was monitored. The experimental variables as well as potential interferences were investigated and the figures of merit of the method were established. Using the selected conditions, the 3 sigma limit of detection for uranium was 0.1 mu g L-1 at a preconcentration time of 480 s and the relative standard deviation was 4.7% at the 5 mu g L-1 level for a preconcentration time of 120 s (n = 8). The accuracy of the method was established by analyzing a reference sea water sample.