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[Display omitted] • A SnO 2 QDs-MXene composite was synthesized for electrochemical detection of luteolin. • The expanded d-spacing of MXene providing abundant active sites for detection. • The SnO 2 QDs-MXene/GCE electrode showed an ultra-low LOD of 0.14 nM. • The SnO 2 QDs-MXene/GCE electrode achieve accurate detection in actual samples. 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 SnO 2 QDs-MXene composite is synthesized for selective electrochemical detection of luteolin. Inserting SnO 2 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 SnO 2 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 SnO 2 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. [ABSTRACT FROM AUTHOR]

Conventional methods like chromatography and spectroscopic analysis have limitations in detecting luteolin. However, electrochemical detection shows promise for reliable analysis. In this study, we compared two different morphologies of SnO 2 with the same crystal structure for luteolin detection and found that crystal morphology significantly impacts the catalytic reaction. Compared to SnO 2 quantum dots (SnO 2 QDs), mesoporous SnO 2 (m-SnO 2) exhibited a larger specific surface area, providing more active sites for oxidation and reduction reactions. Moreover, m-SnO 2 had lower impedance, effectively accelerating charge transfer at the electrode surface. Based on these excellent characteristics, m-SnO 2 /GCE modified electrode demonstrated outstanding performance in detecting luteolin, achieving a sensitivity of 8.5 μA μM-1, a low limit of 0.19 nM and a wide linear range from 0.5 nM to 1,400 nM. Besides, the m-SnO 2 /GC electrode displayed excellent consistency, reproducibility, durability, repeatability and specificity. Even three-week exposure to atmospheric conditions, the DPV signal stood at 94.1 % of its original peak current. Those enables its excellent application in practical sample detection. This research enhances our understanding of the influence of material structure and interface on catalytic luteolin detection, providing a theoretical foundation for accurate detection in complex systems. These findings should contribute to the development of more efficient, sensitive, and reliable luteolin sensors. [Display omitted] • A m-SnO 2 material with outstanding surface area was synthesized. • The m-SnO 2 providing sufficient channels for the movement of luteolin molecules. • The m-SnO 2 electrode showed an ultra-low LOD of 0.19 nM. • The m-SnO 2 electrode achieved accurate detection in actual samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • A SnO 2 quantum dots modified glass carbon electrode is developed. • The SnO 2 QDs/GCE possesses an ultra-low LOD of 0.25 nM toward luteolin. • The SnO 2 QDs/GCE electrode achieves accurate detection of luteolin in actual samples. Although most of the composite based electrocatalysts for determination of luteolin has been developed, the unsatisfactory limit of detection (LOD) and narrow linear range originated from the unstable interface among each component limit their further application. Herein, a SnO 2 quantum dots modified glass carbon electrode (SnO 2 QDs/GCE) is developed for selective detection of luteolin. The electrochemical behavior of luteolin on SnO 2 QDs/GCE indicates that the redox process involves participating of two-electrons/double-protons. The big specific surface area of SnO 2 QDs provides sufficient active sites for the redox reaction of luteolin. On this bases, an ultra-low LOD of 0.25 nM as well as a large linear range of 0.1–1200 nM is obtained for detection of luteolin. Besides, the influence of several coexisting compounds and common ions on the detection of luteolin was evaluated, and no obvious interference was found. Finally, the SnO 2 QDs/GCE electrode achieves accurate detection of luteolin in actual samples including orange, lemon and carrot juices. This work provides new strategy for the determination of luteolin in complex systems. [ABSTRACT FROM AUTHOR]