Adsorptive Square-Wave Voltammetry for the Analysis and Speciation of Complexes of Cd(II)-Ferron

FERNANDO GARAY; VELIA M. SOLIS

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2004 vol. 16 p. 450 - 450

he theory of adsorptive stripping square-wave voltammetry (SWV) for relatively low ligand concentrations is employed to determine the reduction mechanism of Cd(II)-ferron complexes accumulated on a static mercury drop electrode at different pH values. The electrochemical behavior of ferron molecules indicated that the adsorptive concentration of Cd(II) is possible in solutions with 3.5 < pH < 11, providing a wide pH range where the interference of other ligands present in real samples would be not so critical. Cyclic voltammetry experiments were also performed for the purpose of comparison. Fitting between experimental and theoretical square-wave voltammograms shows that the prevailing species at the reaction layer coincide with the equilibrium bulk distribution. The simulation procedure indicated that the electrochemical rate constants of Cd(II)-ferron complexes varied from (6 ± 1) s-1 to (0.17 ± 0.01) s-1 for solutions analyzed at pH 3.9 and 10.8, respectively. Changes at the surfac