Determination of Trace Antimony (III) by Adsorption Voltammetry at Carbon Paste Electrode

This work presents a sensitive method for the determination of trace antimony based on the antimony-pyrogallol red (PGR) adsorption at a carbon paste electrode (CPE). The optimal conditions were to use an electrode containing 25% paraffin oil and 75% high purity graphite powder as working electrode, a 0.10 mol/L HCl solution containing 3.0×10 mol/L PGR as accumulation medium and a 0.20 mol/L HCl solution as electrolyte with an accumulation time of 150 s and a reduction time of 60 s at -0.50 V followed with a sweep from -0.50 V to 0.20 V. The mechanism of the electrode reaction was discussed. Interferences of other metal ions were studied as well. The detection limit was 1×10 mol/L. The linear range was from 2.0×10 mol/L to 5.0×10 mol/L. Application of the proposed method to the determination of antimony in water and human hair samples gave good results.