An analytical solution to linear scan ac voltammetry of a reversible couple

Linear scan ac voltammetry of a reversible couple has been reexamined and an analytical solution has been found without invoking the slow scan approximation. This solution is complete in the sense that it gives explicit formulae for the concentration of both oxidized and reduced species at any time and distance from the electrode. A new term appears in the current expression which mixes the ramp and ac responses. The slow scan approximation, in which the ramp or dc response is assumed to have a negligible effect on the ac response, has been tested and found to be valid at all except the lowest frequencies. For example, the error is less than 5% for a scan rate less than 20nFω/RT. © 1980 Elsevier Sequoia S.A.