Simultaneous adsorptive stripping voltammetric determination of molybdenum(VI), uranium(VI), vanadium(V), and antimony(III)

The simultaneous adsorptive stripping voltammetric (AdSV) determination of the four elements molybdenum, antimony, vanadium, and uranium as their chloranilic acid (2,5-dichloro-4,6-dihydroxy-1,3-benzoquinone) complexes is described, the parameters of the procedure were varied to produce the best peak resolution with regard to the sensitivity. A pH of 2.3-3 (for sweet or sea water, respectively), a chloranilic acid concentration of 1 x 10(-4) mol l(-1) and an accumulation potential of +50 mV were chosen for the analysis. Furthermore, the parameters for the differential pulse mode used were taken into consideration. A set of calibration curves was recorded. The 3 sigma-detection limits were calculated: 0.18 mu g l(-1) for uranium, 0.14 mu g l(-1) for vanadium, 0.27 mu g l(-1) for antimony (III) and 0.07 mu g l(-1) for molybdenum. The method was applied to standardized NASS 4 sea water, sea water from the North Fiji Basin, local potable water, and a sewage sample from a suspended uranium slag heap. The batch-procedure was transferred to an automatic flow-through voltammetric device under parameter optimization. (C) 1999 Elsevier Science B.V. All rights reserved.