PANI-functionalized MXene/SnOx porous heterostructures as a novel electrochemical sensing platform for detecting luteolin in food

Luteolin is a natural flavonoid compound widely found in fruits, vegetables, and herbs. Reasonable intake is beneficial for the treatment of cough, inflammation, cardiovascular disease and other diseases. In this study, MXene/SnO_x composites were first prepared hydrothermally and then functionalized by in situ chemical polymerization to form MXene/ SnO_x/PANI composites with three-dimensional heterogeneous conductive structures. The composites were characterized via SEM, XRD, and XPS. Compared with MXene, the addition of SnO_x results in composites with a larger specific surface area and more exposed active sites. In addition, the in situ polymerization and functionalization of PANI on the surface of MXene/SnO_x promotes an increase in the number of electronic conduction paths in the composite structure and effectively accelerates charge transfer at the electrode interface. The formation of a three-dimensional heterogeneous conductive structure promotes the electrochemical redox process of Lut at the sensing interface. On the basis of these excellent properties, the MXene/SnO_x/PANI modified electrode has outstanding performance in Lut detection, with a detection range of 0.2–6.5 μM and a detection limit of 0.12 μM. In addition, it has excellent repeatability, stability, and anti-interference ability and can be used to accurately determine the Lut content in real Perilla and Chrysanthemum samples, and the results are consistent with those of UV–Vis.