Uranium determination in industrial effluents by voltammetric method using triazene 1-oxide as an alternative binder

This study reports for the first time the uranium (U) determination in industrial effluents by differential pulse adsorptive stripping voltammetry using triazene compound as a binder. Analyses were performed in 0.01 mol L-1 acetate buffer (pH 4.4), and the binder used was 1-methyl-3-(p-carboxyphenyl)triazene 1-oxide with the complex reduction peak at - 0.38 V. A detection limit of 0.06 and a quantification limit of 0.20 mu g L-1 were achieved. The recovery values of spiked samples were between 80 and 100% (RSD less than 10.4%), and the concentration range from 0.35 to 7 mu g L-1 was linear (r(2) = 0.99). The values of U quantified in the samples INB-01, INB-02, INB-03 and INB-04 were 10.74, 30.58, 58.21 and 956.56 mu g L-1, respectively. The complex formed is irreversibly reduced on the electrode surface, with the transfer of two electrons, and the process is controlled by diffusion. Additionally, it is suggested that the U(VI) center coordinates itself to the N and O atoms of six triazene groups forming stable five-membered rings with coordination number equal to twelve and icosahedral geometry.