Full-wave analysis of stripping chronopotentiograms at scanned deposition potential (SSCP) as a tool for heavy metal speciation: Theoretical development and application to Cd(II)-phthalate and Cd(II)-iodide systems

A new mathematical treatment has been developed and implemented in an EXCEL spreadsheet in order to determine average equilibrium functions from the full set of data measured by scanning stripping chronopotentiometry (SSCP) in solutions containing different proportions of heavy metal ions and small-sized ligands. It has been applied to the experimental systems Cd(II)-phthalate and Cd(II)-iodide as models of complexation in the absence and in the presence of electrodic adsorption, respectively. The good agreement between the complexation parameters determined in this way, those predicted from literature data and those obtained using a cadmium ion selective electrode (ISE) confirms the validity of the proposed methodology and encourages its further refining for the analysis of macromolecular and heterogeneous systems.