DETERMINATION OF DIFFUSION-COEFFICIENTS BY MEANS OF NORMAL PULSE VOLTAMMETRY WITH A STATIONARY DISK ELECTRODE

Normal pulse voltammetry with a stationary unshielded disk electrode can be used for determining the diffusion coefficients of electroactive species in an electrolyte solution if the pulse interval is sufficiently long to eliminate the effects of the preceding pulse. Two experimental examples are presented: (1) hexacyanoferrate(III) ions in 1 mol dm-3 KCl solution and (2) thallium(I) ions in 0.5 mol dm-3 KNO3 solution. In the former example, the determined diffusion coefficient agreed with the reference value within 1%. In the latter, the agreement was less satisfactory, presumably due to the fact that the reduced form was deposited on the electrode surface.