Expanded interlayer spacing of SnO₂ QDs-Decorated MXene for highly selective luteolin detection with Ultra-Low limit...

Although there have been advancements in electrochemical catalysts for luteolin detection, their practical use is constrained by low sensitivity, inadequate selectivity, and unsatisfactory limit of detection. MXene, a class of 2D materials, possesses exceptional physical-chemical properties that make it highly suitable for electrochemical detection. Nevertheless, the self-stacking and limited interlayer spacing of MXene impede its extensive application in electrochemical detection. Herein, a SnO₂ QDs-MXene composite is synthesized for selective electrochemical detection of luteolin. Inserting SnO₂ QDs between tightly stacked MXene layers expands the d-spacing of MXene, enhancing the specific surface area and enabling abundant active sites for redox reactions. The inclusion of MXene in the modified SnO₂ QDs-MXene/GCE electrode significantly enhances electron transfer. As a result, the electrode demonstrates exceptional luteolin detection capabilities, including a wide linear range (0.1-1200 nM), high sensitivity (12.4 μA μM^-1), and an ultra-low limit of detection (0.14 nM). Additionally, the SnO₂ QDs-MXene/GCE electrode exhibits good repeatability, excellent reproducibility, remarkable stability, and high selectivity, making it suitable for practical sample analysis. This research contributes to advancing ultra-low limit of detection sensors for accurate luteolin detection.