▎ 摘　　要

A comparison of the analytical characteristics of two tyramine biosensors, based on graphene oxide (GRO) and polyvinylferrocene (PVF) modified screen-printed carbon electrodes (SPCE), is reported. Diamine oxidase (DAOx) or monoamine oxidase (MAOx) was immobilized onto the PVF/GRO modified SPCE to fabricate the biosensors. Surface characteristics and electrochemical behaviour of the modified SPCEs were investigated by atomic force microscopy (AFM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and cyclic voltammetry (CV). Electrode surface composition and experimental variables such as pH and working potential were optimized in order to ensure a high performance. Under optimum experimental conditions, both DAOx/PVF/GRO/SPCE and MAOx/PVF/GRO/SPCE biosensors exhibited wide linear dynamic ranges for tyramine from 9.9x10(-7) to 1.2x10(-4) M and from 9.9x10(-7) to 1.1x10(-4) M, respectively. MAOx/PVF/GRO/SPCE biosensor showed higher sensitivity (11.98 mu A mM(-1)) for tyramine determination than the DAOx/PVF/GRO/SPCE biosensor (7.99 mu A mM(-1)). The substrate specifity of the biosensors to other biogenic amines namely histamine, putrescine, spermine, spermidine, tryptamine, beta-phenylethylamine and cadaverine was also investigated. The developed biosensors were successfully used for tyramine determination in cheese sample.