Abstract: An osmium bipyridine-containing redox polymer (POs-EA) film-modified gold electrode based on an electrochemical reduction method was developed. The POs-EA film-modified gold electrode exhibited classical features of a kinetically fast redox couple bound to the electrode surface and excellent electrocatalytic activity towards the oxidation of epinephrine. In contrast to a bare gold electrode, the oxidation current of epinephrine increased greatly and the oxidation peak potential shifted negatively to about 0.29 V (vs SCE) over the redox polymer film-modified electrode. Furthermore, the possible catalytical mechanism of epinephrine oxidation was proposed. Amperometric measurements were performed at an applied potential of 0.29 V and a linear response of epinephrine was obtained in the range of 5×10-8～1×10-5 mol/L with a detection limit of 1.5×10-8 mol/L. The proposed procedure was successfully applied to the determination of epinephrine in epinephrine hydrochloride injections.

Key words: osmium bipyridine, redox polymer, modified electrode, epinephrine, electrocatalysis, amperometric determination