▎ 摘　　要

A fast and simple immobilization of glucose oxidase (GOx) used for fabrication of highly sensitive, quick response (< 2 s) and low cost glucose biosensor. GOx enzyme was immobilized covalently on graphene oxide (GO) modified pencil graphite electrode (PGE) and simultaneously GO was reduced by chronoamperometric and cyclic voltammetric methods. The fabricated biosensor by chronoamperometry showed sharper redox peaks current for GOx in comparison with cyclic voltammetry. Attenuated transmission reflectance (ATR) spectroscopy was used for characterization of covalent immobilization of GOx. The immobilization time of GOx on GO was shortened to 30 s, the minimum immobilization time in other works was 20 minutes, after drying of GO-GOx paste on the PGE. The electrochemical properties of the fabricated biosensor were studied by cyclic voltammetry (CV) and chronoamperometry. The cyclic voltammetric behavior of the fabricated electrode shows a pair of well-defined peaks with a formal potential of -0.521 V and peak to peak separation of 35 mV, indicating direct electron transfer between GOx and electrode. The fabricated biosensor shows a fast electron transfer of k(s)=5.84 s(-1), a high affinity for glucose with Michaelis-Menten constant K-m = 0.215 mM, a high sensitivity of 278.4 mu A mM(-1) cm(-2), a low detection limit of 0.61 mu M, and a linear range of 40 to 600 mu M. The fast and simple immobilization and GO reduction method can be used in fabrication of other electrochemical biosensors and biofuel cells with low costs.