Near-steady-state cyclic voltammetry at microelectrodes

Cyclic voltammetry at hemispherical or disc microelectrodes yields steady-state voltammograms only if the scan rate is sufficiently slow. Because convection interferes if the scan is too slow, this places an upper limit on the size of microelectrodes that can be used for steady-state measurements. This limit has been quantified by deriving the equation that describes near-steady-state cyclic voltammetry at reversible microelectrodes. For larger electrodes, the average of the forward and backward branches of the cyclic voltammogram provides a useful substitute for the true steady-state voltammogram, provided that corrections are made that account for the discrepancies between the heights and widths of the two waves. A more powerful procedure, convolutive forecasting, is then described which exactly converts a non-steady-state voltammogram into a steady-state voltammogram. Convolutive forecasting applies to any experimental method, to reactions of any degree of reversibility, to microelectrodes of any size, and to any scan rate fast enough to inhibit convection.