SUBSTITUTIONAL STRIPPING VOLTAMMETRY OF REVERSIBLE REDOX SPECIES BY SELF INDUCED REDOX CYCLING - ELECTROCHEMICAL SUBSTITUTED PRECONCENTRATION USING MICRO-MACRO TWIN ELECTRODE

A new type of stripping voltammetry utilizing the self induced redox cycling effect has been developed in order to detect trace amounts of electrochemically reversible redox species. This was achieved by combining an interdigitated array (IDA) electrode in a sample solution containing reversible redox species in one cell compartment with a macro electrode in another cell compartment containing a different redox species which deposits reversibly on the electrode. The preelectrolysis of the reversible species at one finger set of the IDA induced a reverse reaction at the other set. The charge produced by this reverse reaction was transmitted to the macroelectrode in the other cell through a lead, and the electroactive species is deposited on the macroelectrode. When the potential of the macroelectrode is swept, the deposited material generates a highly amplified stripping current which is in proportion to the redox species concentration. Dissolved redox species either in an oxidized and reduced state could be detected quantitatively using heavy metal ions and halides, respectively. The magnitude of the signal could be controlled by changing the preelectrolysis time and the concentration of the depositing material. The value of the redox potential could be obtained by changing the preelectrolysis potential.