Analytical Sciences

Abstract − Analytical Sciences, 25(7), 903 (2009).

Applicability of 2-Hydroxybenzaldehyde Benzoylhydrazone in the Determination of Trace Metals by Adsorptive Cathodic Stripping Voltammetry: Relevancy of Simultaneous Determinations
Department of Analytical Chemistry, Faculty of Sciences, University of Cadiz, P. O. Box 40, Campus Río S. Pedro, Puerto Real, Cádiz 11510, Spain
The applicability of 2-hydroxybenzaldehyde benzoylhydrazone (2-HBBH) for determining Cd(II), Cu(II), Pb(II) and Bi(III) ions by adsorptive cathodic stripping voltammetry was studied. The sensitivity of metal reduction peak currents was highly enhanced with the addition of 2-HBBH to metallic solutions, showing the adsorptive characteristics of the complexes. Variable factors affecting the response (mainly: the influences of pH, supporting electrolyte and deposition potential on selectivity and sensitivity) were investigated. Limits of detection suitable for trace analysis were obtained: 0.28 μg L−1 for Cd(II) at pH 10; 0.026 μg L−1 for Pb(II) at pH 9; 0.285 μg L−1 for Bi(III) at pH 8 and 0.051 μg L−1 for Cu(II) at pH 9.5. Simultaneous determinations of two groups of elements, consisting of Cd(II)-Pb(II)-Cu(II) and Cd(II)-Pb(II)-Bi(III), at pH 9.5 and 9, respectively, were described with good resolution and sensitivities. Metals were quantified at concentrations in the range from 0.5 to 14 μg L−1. The RSD at a concentration level of 5 μg L−1 of metal was 4.28% for Cd(II), 2.99% for Pb(II), 4.82% for Bi(III) and 1.35% for Cu(II). The method was applied to the simultaneous determination of metals in certified reference water (TMDA-62) and in synthetic water samples with satisfactory results.