LACCASE BIOSENSOR BASED ON GRAPHENE-CHITOSAN COMPOSITE FILM FOR DETERMINATION OF HYDROQUINONE

摘要

A novel laccase biosensor was fabricated by entrapping laccase in graphene-chitosan composite materials and applied to determine hydroquinone. The graphene-chitosan composite had good conductivity, high stability, and good biocompatibility. Laccase was firmly embedded into the composite without other cross-linking reagents. The morphology and electrical conductivity of graphene-chitosan film were measured by scanning electron microscopy and electrochemical impedance spectroscopy. This biosensor catalyzed the oxidation of hydroquinone to p-quinone and the reduction back to hydroquinone. The cathodic peak current of hydroquinone increased significantly with concentration in the range of 2.0×10~(-6) to 1.0×10~(-4) mol ?L~(-1) (r=0.9975) with a limit of detection of 2.6×10~(-7)mol?L~(-1). The response time of the biosensor to reach 95% of its steady-state current was less than 10 s. Moreover, the biosensor exhibited good stability, reproducibility, and selectivity.