Electrochemical behaviour of the ubiquinone-Q₁₀ film coated onto a glassy carbon electrode by the spinner method

The charge transfer mechanism of ubiquinone-Q₁₀ (UQ₁₀, coenzyme-Q₁₀) coated onto a glassy carbon electrode (UQ-GCE) by the spin coating method was investigated in aqueous electrolyte solution. Two different charge transfer processes controlling the redox reaction of UQ₁₀ at different sites of the UQ₁₀ film are proposed. One process is assigned to the inter- and/or intra-molecular proton transfer process occurring at monolayer sites of the UQ₁₀ film. The other process is assigned to the electron transfer process between adjacent UQ₁₀ molecules taking place at the inner layer of multilayer sites of the film. The apparent diffusion coefficients of these charge transport species in monolayer and multilayer film are calculated to be 9.7×10^-14 and 2.7×10^-11 cm²/s, respectively.