Construction of multi-component CuO/ZIF-8@CNTs modified electrode for sensitive electrochemical detection of neohesperidin dihydrochalcone in liquor samples

A sensitive electrochemical sensor was proposed for neohesperidin dihydrochalcone (NHDC) detection using copper oxide/ zinc imidazole framework 8@ carbon nanotubes modified glassy carbon electrode (CuO/ZIF-8@CNTs GCE). The multi-component CuO/ZIF-8@CNTs GCE was prepared by two-step drop-casting method and characterized by Field-emission scanning electron microscopy (FE-SEM). The effective combination of CuO and ZIF-8@CNTs enhanced the electron transfer and catalytic activity of the electrode and greatly strengthened the oxidation current of NHDC, which was about 5.6-fold that of the CuO GCE and 2.3-fold that of the ZIF-8@CNTs GCE. Inspired by this, the CuO/ZIF-8@CNTs GCE was used for NHDC detection and some crucial parameters were optimized. The reaction mechanism at CuO/ZIF-8@CNTs GCE was confirmed to involve two-step two-electron process by cyclic voltammetry (CV) measurements. Finally, the sensor achieved NHDC detection ranging from 0.03 to 10 μM using differential pulse voltammetry (DPV) technique, with a detection limit of 16.0 nM. The satisfactory recoveries of 92.9% to 107.8% in liquor samples also demonstrated its practicability in actual samples, matching well with that of high-performance liquid chromatography (HPLC). This work not only designs a simple detection method for NHDC but also opens up a paradigm for leveraging multi-component MOF composite electrode materials for food safety monitoring.