A core–shell molecularly imprinted polymer grafted onto a magnetic glassy carbon electrode as a selective sensor for the determination of metronidazole

A sensitive and selective electrochemical sensor for metronidazole (MNZ) was developed. The core–shell metronidazole-magnetic molecularly imprinted polymer (MMIP) was synthesized and then attached to the surface of magnetic glassy carbon electrode (MGCE) with the help of magnetic force in order to prepare MMIP/MGCE sensor. The performance of the obtained imprinted sensor was investigated by cyclic voltammetry and electrochemical impedance spectroscopy. Various factors, known to affect the response behavior of the MMIP/MGCE electrode, were studied and optimized. The imprinted sensor exhibits high recognition ability and affinity for MNZ in comparison with the nonimprinted one. In addition, the MMIP/MGCE also shows good stability and acceptable reproducibility for the determination of MNZ. Under the optimal experimental conditions, the current response of the electrochemical sensor was linear to MNZ concentrations in the range from 5.0 × 10−8 to 1.0 × 10−6 M, with the detection limit of 1.6 × 10−8 M. The method was successfully applied to the analysis of MNZ in milk samples and honey samples with acceptable recoveries of 93.5–102.2%.