Three-dimensional voltammetry assisted by parametric signal fitting: A new perspective for the electrochemical evaluation of metal binding in the presence of electrodic adsorption

• 3D-voltammograms are obtained by integration of multiple chronoamperograms.
• A new chemometric method is proposed for the analysis of 3D-voltammograms.
• It fits time-dependent parametric waves and peaks to the signals along the matrix.
• It allows the separation of adsorptive and diffusive contributions to the current.
• Augmented matrices allow the analysis of 3D-voltammetric titrations.

A new perspective of three-dimensional voltammetry is given for the study of metal complexation in the presence of adsorption phenomena and, eventually, when the electrochemical reversibility of the processes decreases. For this purpose, 3D-voltammograms are obtained as usual, i.e., by combination of chronoamperograms measured at different potential steps, but they are analysed by the new methodology of parametric signal fitting (PSF), which uses the full data matrix to fit a five-parameter equation to every component. The parametric signals can be time-dependent peaks or waves and the optimised parameters inform about the concentrations in both dissolved and adsorbed phases. The analysis can be carried out on both individual and augmented matrices. The preliminary tests on the well-known Cd(II)-glutathione system yield promising results and encourage the combination of 3D-voltammetry and PSF as a complementary tool for the study of metal complexation in complicated systems.

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