Determination of Ferrocene Solubility by Normalized Chronoamperometry: An Evaluation of Experimental Constraints

The determination of ferrocene solubilities in aqueous ethanol mixtures by normalized chronoamperometry is described. Normalized chronoamperometry has been used to determine D without prior knowledge of n or C, although little information is available regarding the experimental limitations of this technique. A comparison of 1,1′-ferrocenedimethanol diffusion coefficients obtained using voltammetry and normalized chronoamperometry indicates that analyte concentrations less than 3 mM may lead to an underestimation of the diffusion coefficient for a single electron transfer process. The use of normalized chronoamperometry to measure diffusion coefficients in aqueous ethanol solutions was validated via the Stokes-Einstein equation.