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

Abstract

This work presents a sensitive method for the determination of trace antimonybased 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 containing3.0×10-5 mol/L PGR as accumulation medium and a 0.20 mol/L HCl solution aselectrolyte with an accumulation time of 150 s and a reduction time of 60 s at -0.50 Vfollowed with a sweep from -0.50 V to 0.20 V. The mechanism of the electrode reactionwas discussed. Interferences of other metal ions were studied as well. The detection limitwas 1×10-9 mol/L. The linear range was from 2.0×10-9 mol/L to 5.0×10-7 mol/L.Application of the proposed method to the determination of antimony in water andhuman hair samples gave good results.

Keywords

• antimony
• pyrogallol red
• carbon paste electrode
• adsorptive voltammetry.