Electrochemical Sensor Based on CeO ₂ Nanozyme-Mediated UiO-66-NH ₂ Adsorption-Catalysis Synergistic Nanosystem for Rutin Detection in Chinese Medicinal Materials

Rutin (Rut) is a bioactive flavonoid widely found in buckwheat, sophora flowers, ginkgo leaves and various traditional Chinese medicinal herbs. It exhibits antioxidant, anti-inflammatory, hypolipidemic and cardiovascular protective effects, showing great application potential in nutrition and pharmacology. In this work, a highly sensitive electrochemical sensor was constructed for Rut detection by modifying a glassy carbon electrode (GCE) with a nanocomposite consisting of multiwalled carbon nanotubes (MWCNTs), amino-modified zirconium-based MOF (UiO-66-NH 2 ), gold nanoparticles (AuNPs) and cerium dioxide (CeO 2 ).The reversible Ce 3+ /Ce 4+ redox pair in CeO 2 endows the material with peroxidase-like catalytic activity. Combined with the porous structure of UiO-66-NH 2 and the conductive network of MWCNTs/AuNPs, a synergistic adsorption-catalysis interface is formed, which significantly accelerates the electrocatalytic oxidation of Rut. Systematic characterizations by SEM, TEM, XRD, XPS, CV, EIS and SWV show that the sensor has a linear range of 0.04–9 μM, a detection limit of 5.6 nM, and excellent stability, anti-interference ability and selectivity. It can accurately determine Rut content in real samples such as white chrysanthemum, wolfberry and mint, and the results are consistent with those of high-performance liquid chromatography (HPLC). This CeO 2 -based nanozyme sensor offers a reliable strategy for rapid and sensitive Rut analysis in complex food and pharmaceutical samples.