Electrochemical and Electrocatalytic Properties of Ferrocene Incorporated in L‐Cysteine Self‐Assembled Monolayers on a Gold Electrode

Abstract

The preparation of a gold electrode modified by aminylferrocene (FcAI) covalently bound to L‐cysteine self‐assembled monolayer (L‐Cys/Au SAM) was described, and characterized by cyclic voltammogram (CV) and electrochemical impedance spectroscopy (EIS). In pH 7.4 buffers, FcAI incorporated in L‐Cys/Au SAM gave a pair of well‐defined and quasi‐reversible cyclic voltammetric peaks at 0.109 vs. saturated calomel eletrode (SCE), characteristic of Fe(II)/Fe(III) redox couples of the Fc. The apparent surface electron transfer rate constant is 6.86 s⁻¹ at the modified electrode. The immobilized Fc gave an excellent electrocatalytic activity for the oxidation of epinephrine (EP). The catalytic current of EP vs. its concentration has a good linear relation in the range of 1.7×10⁻⁷–1.0×10⁻⁴ mol/L, with the correlation coefficient of 0.9975 and detection limit of 1.8×10⁻⁸ mol/L. The modified electrode can be used for the determination of EP in practical injection. The method is simple, quick, sensitive, and accurate.

Keywords:

• Electrocatalysis
• ferrocene
• L‐cysteine
• self‐assembled monolayer
• epinephrine

The Project was financially supported by the Nature Science Foundation of Anhui Province (No. 050460301).