DETERMINATION OF TRACE AMOUNTS OF ANTIMONY(III) BY DIFFERENTIAL-PULSEANODIC-STRIPPING VOLTAMMETRY AT A PHENYLFLUORONE-MODIFIED CARBON-PASTE ELECTRODE

Antimony(III) was selectively accumulated, at open circuit, on a carbo n paste electrode incorporating phenylfluorone. The ensuing measuremen t was carried out by differential-pulse anodic stripping voltammetry a fter reducing the Sb-III to Sb-0. Factors affecting the accumulation, reduction and stripping steps were investigated and an optimized proce dure was developed, Under optimized conditions, the calibration curve was linear in the range 2.00 X 10(-8)-1.00 X 10(-6) mol l(-1). A detec tion limit of 8.9 X 10(-9) mol l(-1) (S/N = 3) was found for 10 min ac cumulation. For eight successive determinations of 3.00 X 10(-8) and 1 .00 X 10(-7) mol l(-1) Sb-III, RSDs of 9.63 and 4.03%, respectively, w ere obtained. Interferences from selected metals and other inorganic i ons and organic substances were examined. The developed method was app lied to Sb determinations in a human hair and a soil sample.