▎ 摘　　要

A simple, sensitive and selective electrochemical method was developed for the determination of morphine using a graphite screen printed electrode (SPE) modified with the magnetic core-shell graphene oxide (GO)/Fe3O4@SiO2 nanocomposite using cyclic voltammetry, differential pulse voltammetry (DPV) and chronoamperometry techniques. The magnetic core-shell GO/Fe3O4@SiO2 nanocomposite was prepared via a facile and simple process. The prepared nanocomposite modified SPE showed enhanced peak currents for the oxidation of morphine compared to the bare SPE. Under optimum conditions the sensor provided linear DPV responses in the range of 1.0-100 mu M for morphine with a detection limit of 7.5 x 10(-7) M. The proposed sensor was successfully applied to morphine monitoring in biological fluids and satisfactory results were obtained.