Applicability of 2-Hydroxybenzaldehyde Benzoylhydrazone in the Determination of Trace metals by Adsorptive Cathodic Stripping Voltammetry: Relevancy of Simultaneous Determinations

Abstract

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.