▎ 摘　　要

In the present work, a nickel-ferrite/reduced-graphene-oxide composite was synthesized by a hydrothermal co-precipitation approach. The obtained materials were characterized by using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray microscopy (mapping energy dispersive X-Ray), adsorption/desorption isotherms of nitrogen, vibrating sample magnetometer, X-ray photoelectron microscopy, and Raman spectroscopy. The obtained composite with a large surface area consists of highly dispersed nickel-ferrite nanoparticles (7-10 nm) over reduced-graphene-oxide layers. In addition, this composite possesses high magnetization saturation with a soft magnetic property. A sensitive electrochemical sensor for the determination of clenbuterol was manufactured by modifying a glassy-carbon electrode with nickel ferrite/reduced graphene oxide composite film. The peak current measured with differential pulse voltammetry for clenbuterol solutions is linearly proportional to its concentration ranging from 0.99 to 18.03 mu M with a limit of detection of 0.17 mu M and a limit of quantification of 0.52 mu M. Furthermore, the reproducibility, precision, and accuracy of the proposed method were also investigated. This proposed method was applied to detect clenbuterol in pig urine samples with satisfactory results.