Adsorptive Stripping Voltammetric Determination of Lead and Cadmium in Natural Waters in the Presence of Rutin Using a Nafion–Mercury Coated Film Electrode

摘要

A sensitive method for the simultaneous determination of Pb(II) and Cd(II) based on the formation oftheir complexes with rutin (RUT) and subsequent adsorptive deposition on a Nafion–mercury coatedglassy carbon electrode (GC-NHgFE) is presented. The effects of various operational parameters suchas pH, ligand concentration, accumulation potential, and time were optimized. The best experimentalconditions found were: pH 3.5; CRUT: 0.10 mmol L–1; tads: 100 s, and Eads: 0.15 V. Under theseconditions, the reductions signals of Pb–RUT and Cd–RUT complexes are found at –0.29 V and –0.46V, respectively, while no signal of free RUT was seen. The relationship between peak current andPb(II), Cd(II) concentrations are linear in the 1.0–62.0 μg L–1 range. The detection limits (DLs) werefound to be 0.16 and 0.06 μg L?1 for Pb(II) and Cd(II), respectively. Finally, the method was applied tothe determination of Pb(II) and Cd(II) in water from the Ambala river (Colombia) and in commercialmineral water with satisfactory results.