Coaxial carbon fiber/ZnO nanorods as electrodes for the electrochemical determination of dopamine

Abstract

In this paper, coaxial carbon fiber/ZnO nanorod fibers (CF/ZnONR) were synthesized by a plasma-assisted strategy with carbon fiber templates and characterized by scanning electron microscopy, which revealed that ZnO was attached on to the surface of the carbon nanofibers. The as-synthesized fibers were used to fabricate microelectrodes and exhibited a strong electrocatalytic activity towards the oxidation of dopamine (DA). The sensor performed at a sensitivity of 9.84 μA μM⁻¹ with a detection limit of 0.07 μM. Moreover, the mechanism of catalytic oxidation of DA on the ZnONR surface is discussed. This biosensor demonstrates that biomolecules such as DA can be detected by a simple and quick method, without the assistance of specific functional biomolecules such as enzymes. Finally, the method was applied to the selective and precise analysis of DA in commercial injections and serum samples.