Depletive Stripping Chronopotentiometry: A Major Step Forward in Electrochemical Stripping Techniques for Metal Ion Speciation Analysis

Abstract

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.

Electrochemical Methods for Speciation of Trace Elements in Marine Waters. Dynamic Aspects

“…The potentialities/limitations of SSCP were reviewed by the same authors and compared with other stripping techniques. 79 The SSCP curve is constructed from a series of individual depletive SCP curves measured at different deposition potentials (E d ), varying from values in the limiting current to the potential range where no further metal reduction occurs. Representing τ vs E d a sigmoidal-shape curve is obtained ( Figure 5).…”

Electrochemical Sensors

“…Zen and Kumar reviewed clay mineral electrodes for chemical sensor applications (43 references Town and van Leeuwen comparatively evaluated various modes of stripping chronopotentiometry for trace level speciation analysis (66 references). 57 The authors stress the advantages of depletive stripping potentiometry at scanned deposition potential, which including greater resolution and, in some cases, improved selectivity, and include some theory. Samec et al reviewed progress of realizing amperometric ion sensors on the basis of ion amperometry at the interface between two immiscible electrolyte solutions (105 references).…”

Fractionation and Speciation of Trace Elements in Soil Solution

“…This technique has broadened the application range of voltammetry to a large number of elements; however, more work is still needed to evaluate its reliability for routine and multielement analysis [111]. Other promising stripping techniques for speciation analyses are anodic stripping chronopotentiometry (SCP) and SCP at scanning deposition potential, SSCP [116,117] and the 'absence of gradients and Nernstian equilibrium stripping' (AGNES) technique. Anodic stripping chronopotentiometry is somewhat less sensitive than SWASV, but also less sensitive to redox reversibility, and much less prone to artefacts due to adsorption, compared with ASV techniques [111].…”