A novel electrochemical sensor based on MnOOH nanorod/expanded graphite for sensitive monitoring of metronidazole

Strict quantification of metronidazole (MNZ, one kind of nitroimidazole antibiotic) plays extraordinary roles for human health due to the serious toxicity arose from overuse of MNZ. In this research, a novel electrochemical sensor is proposed for sensitive quantitation of MNZ. This sensor is constructed using a composite of MnOOH nanorods and expanded graphite (MnOOH/EG), synthesized by a hydrothermal method. The morphological analyses and electrochemical capability tests through various analytical techniques (e.g., microscopic and electrochemical methods) exposit that MnOOH/EG composite displays prominent electrocatalytic activity and sensing capability for quantification of MNZ. A synergistic effect between EG and MnOOH is revealed, where EG offers a high electrode active area and a strong electron-transport ability, while MnOOH features outstanding electrocatalytic behavior. This novel electrochemical sensor displays high sensitivity toward voltammetric quantification of MNZ with detection limit of 17 nM. Moreover, this developed MnOOH/EG electrochemical sensor also demonstrates prominent reproducibility and repeatability as well as high selectivity in the quanti-tative analysis of MNZ. Beyond that, the constructed sensor has been also successfully applied in quantitative analysis of MNZ in commercial drugs and environmental water samples. Consequently, the MnOOH/EG com-posite presented here has strong potential to be employed as a sensing material for constructing electrochemical sensor in widespread fields.