A highly sensitive electrochemical biosensor for phenol derivatives using a graphene oxide-modified tyrosinase electrode.

The fabrication, characterization and analytical performance were investigated for a phenol biosensor based on the covalent bonding of tyrosinase (TYR) onto a graphene oxide (GO)-modified glassy carbon electrode (GCE) via glutaraldehyde (GA). The surface morphology of the modified electrode was studied by atomic force microscope (AFM) and field-emission scanning electron microscopy (FE-SEM). The fabricated TYR/GA/GO/GCE biosensor showed very good stability, reproducibility, sensitivity and practical usage. The catechol biosensor exhibited a wide sensing linear range from 5×10-8 M to 5×10-5 M, a lower detection limit of 3×10-8 M, a current maximum (Imax ) of 65.8μA and an apparent Michaelis constant (Km app ) of 169.9μM.