STRIPPING VOLTAMMETRY OF URANIUM BASED ON ADSORPTIVE ACCUMULATION OF ITS 4-(2-PYRIDYLAZO) RESORCINOL COMPLEX AT THE STATIC MERCURY DROP ELECTRODE

A highly sensitive electrochemical stripping procedure for uranium is reported. Accumulation is achieved by controlled adsorption of the uranium/4-(2-pyridylazo) resorcinol complex on the static mercury drop electrode. The effect of various operational parameters on the stripping response is discussed. The detection limit is 0.2 nM with 10 min preconcentration. The response is linear over a 9.3 x 10(-9)-3.0 x 10(-6) M concentration range, and the relative standard deviation (at the 24-mu-g.l-1 level) is 3%. Most cations and anions do not interfere in the determination of uranium; some interferences are eliminated by the addition of CDTA and EDTA. The applicability of the method to fresh water and seawater is demonstrated (the results obtained for uranium in reference seawater samples, NASS-2, were 2.95-mu-g.l-1 with standard deviations of 0.20-mu-g.l-1 (n = 5).