Depletive stripping chronopotentiometry: A major step forward in electrochemical stripping techniques for metal ion speciation analysis

A comparative evaluation of the utility of the various modes of stripping chronopotentiometry (SCP) for trace metal speciation analysis is presented in the broad context of stripping voltammetric techniques. The remarkable fundamental advantages of depletive SCP at scanned deposition potential (SSCP) are highlighted, and the rigorous underpinning theory is described. The distinctive features of SSCP include: i) an effective getting around part of the Nernstian extension of the reoxidation process, leading to ii) greater resolution than conventional stripping voltammetries; iii) a certain insensitivity to electrochemical irreversibility, especially at a microelectrode; iv) in principle, freedom from induced metal ion adsorption interferences; v) no requirement for excess ligand during stripping; and vi) ability to provide a certain measure of any chemical heterogeneity in the metal speciation that is easily distinguishable from effects of electrochemical irreversibility.