Differential cyclic voltammetry for selective and amplified detection

We propose to combine two existing electrochemical techniques, cyclic voltammetry (CV) and redox cycling (RC), in order to obtain amplified and selective detection of redox active species. This combination is achieved by applying CV waveforms to two electrodes spaced 1.20 mu m apart, with one of the electrodes at a constant potential offset compared to the other. Due to this potential offset we have named this technique differential cyclic voltammetry (DCV). Analytical expressions for the DCV voltammogram are derived and an optimal potential offset is calculated. The optimal voltage difference for the trade-off between peak height and width is 0.1 V for redox couples with n = 1. Experimental voltammograms show good agreement with the analytical expressions. The voltammogram for ferrocenedimethanol has been fitted (R-2 = 0.9985) using only the distance between the electrodes as fitting parameter. Therefore, this technique shows promise as a tool for amplified and selective detection of redox active species.