Determination of trace amounts of antimony(III) by differential-pulse anodic stripping voltammetry at a phenylfluorone-modified carbon paste electrode

Antimony(III) was selectively accumulated, at open circuit, on a carbon paste electrode incorporating phenylfluorone. The ensuing measurement was carried out by differential-pulse anodic stripping voltammetry after reducing the SbIII to Sb0. Factors affecting the accumulation, reduction and stripping steps were investigated and an optimized procedure was developed. Under optimized conditions, the calibration curve was linear in the range 2.00 × 10–8–1.00 × 10–6 mol l–1. A detection limit of 8.9 × 10–9 mol l–1(S/N = 3) was found for 10 min accumulation. For eight successive determination of 3.00 × 10–8 and 1.00 × 10–7 mol l–1 SbIII, RSDs of 9.63 and 4.03%, respectively, were obtained. Interferences from selected metals and other inorganic ions and organic substances were examined. The developed method was applied to Sb determinations in a human hair and a soil sample.