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

Abstract

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 Sb^III 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 Sb^III, 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.