Determination of reaction rate between cathodically formed FeII-triethanolamine-complex and FeIII-hepta-d-gluconate complex by cyclic voltammetry

Electron transfer reactions between ironII/III-complexes are of general interest for corrosion processes, biological processes and technical applications. The cathodic reduction of FeIII-triethanolamine (TEA) complex to form the FeIITEA-form of the complex has been examined by cyclic voltammetry. In the presence of FeIII-d-heptagluconate (HDGL), complex catalytic currents are observed due to homogenous chemical reaction between FeIITEA and FeIII(HDGL)2 which regenerates FeIIITEA. This method can be used to determine the rate constant of the redox reaction between FeIITEA and FeIII(HDGL)2 with k f ′ = 88 ± 12 dm 3 mol - 1 s - 1 .