Simultaneous determination of trace uranium(VI) and zinc(II) by adsorptivecathodic stripping voltammetry with aluminon ligand

Uranium(VI) complexed with aluminon (3-[bis(3-carboxy-4-hydroxy-phenyl)meth ylene]-6-oxo-1,4-cyclohexadiene-1-carboxylic acid triammonium salt) was det ermined by adsorptive cathodic stripping voltammetry (ACSV) using a hanging mercury drop electrode. Trace uranium(VI) and zinc(II) can be simultaneous ly determined in a single scan in the presence of aluminon and urea. Optima l conditions were found to be: accumulation time; 180-200 s, accumulation p otential; 50 mV versus Ag/AgCl, scan rate; 40 mV s(-1), supporting electrol yte; 0.1 M sodium acetate buffer at pH 6.5-7.0, and concentration of alumin on; 1 x 10(-6) M. The linear range of uranium(VI) and zinc(II) were observe d over the concentration range 2-33 and 30-120 ng ml(-1), respectively. The detection limit (S/N = 3) are 0.2 ng ml(-1) (uranium) and 30 ng ml(-1) (zi nc). A good reproducibility shows RSDs of 2.5-4.0% (n = 10). The procedure offers high selectivity, with the presence of urea masking some metal ions. (C) 2000 Elsevier Science B.V. All rights reserved.