Comparative study of cyclic voltammetry with potentiometric analysis for determining formation constants for polyaminocarboxylate-metal ion complexes

Cyclic voltammetry offers a convenient route towards the determination of l igand protonation/deprotonation constants and also for metal-ligand complex stability constants in aqueous media. The utility of voltammetry is exempl ified by a comparison of the metal-ligand stability constants of complexes of ethylenediamine (ED), ethylenediamine-N,N,N',N'-tetra-acetic acid (H(4)E DTA) and diethylenetriamine-N,N,N',N",N"-penta-acetic acid (H(5)DTPA) with transition metals, with these stability constants being in good agreement w ith those obtained using potentiometric analysis. Further support for the u sefulness of voltammetry as an analytical tool is the good correlation of t he protonation constants for (S,S)-ethylenediamine-N,N'-disuccinic acid wit h those determined potentiometrically. (C) 2001 Published by Elsevier Scien ce B.V.