Determination of Sb(III) using an ex-situ bismuth screen-printed carbon electrode by adsorptive stripping voltammetry

Abstract

The determination of Sb(III) on an ex-situ bismuth screen-printed carbon electrode (ex-situ BiSPCE) by means of adsorptive stripping voltammetry (AdSV) using quercetin-5′-sulfonic acid as chelating agent was optimized. The effect of different experimental parameters such pH, ligand concentration (CQSA), accumulation potential (Eacc) and accumulation time (tacc) were studied to obtain a wide linear range, the highest sensitivity and the lowest detection limit. Ex-situ BiSPCE was analytically compared with a sputtered bismuth screen-printed electrode (BispSPE) under optimal conditions. The obtained analytical parameters suggest that ex-situ BiSPCE behaves much better than BispSPE and the first was selected for this study. Optimal parameters were pH=4.6; CQSA=10.0 to 20.0×10−6 mol L−1; Eacc=−0.5 V and tacc=60 s. Peak area is proportional to Sb(III) concentration up to 100.0 μg L−1 (tacc 60 s) and 45.0 μg L−1 (tacc 120 s) range, with detection limits of 1.2 μg L−1 (tacc 60 s) and 0.8 μg L−1 (tacc 120 s). The relative standard deviation for a Sb(III) solution (20.0 μg L−1) was 3.9% for ten successive assays. Thus, the effect of various interfering metal ions was studied and the methodology was validated using a spiked groundwater reference material with very satisfactory results.