DETERMINATION OF ANTIMONY IN IMPURE ZINC-SULFATE SOLUTION BY COPRECIPITATION FOLLOWED BY DIFFERENTIAL-PULSE ANODIC-STRIPPING VOLTAMMETRY

A simple coprecipitation technique for the quantitative separation of the antimony present in impure zinc sulphate electrolyte followed by i ts voltammetric determination is described. Antimony in microgram leve ls is separated from the matrix zinc sulphate solution, which contains higher levels of copper, lead and cadmium, and is subsequently determ ined by differential pulse anodic stripping voltammetry (DPASV) in 3 M hydrochloric acid. Hydrous manganese dioxide is employed as the colle ctor. This procedure, which effects considerable saving in time, is of comparable accuracy to the conventional spectrophotometric method usi ng the antimony-rhodamine B complex. A series of synthetic zinc sulpha te solutions spiked with known amounts of antimony as well as plant so lutions gave near theoretical values.