Highly sensitive electrochemical determination of quercetin based on PMo12@UiO-66-NH2@CNTs nanocomposite

Quercetin (Qu), a naturally occurring flavonoid, is critically involved in sustaining human physiological health. Therefore, it is imperative to rationally design a proficient electrochemical sensor capable of sensing Qu. Herein, a ternary nanocomposite composed of Keggin-type polyoxometalate (PMo 12 ), carbon nanotubes (CNTs), and zirconium-based MOF (UiO-66-NH 2 ) was successfully fabricated to develop a sensitive electrochemical sensor for Qu determination. Benefiting from the synergistic integration of diverse components, the high conductivity of CNTs, good electrocatalytic performance of PMo 12 , and favorable adsorption capacity of UiO-66-NH 2 jointly facilitated the adsorption and electron transfer process of Qu at the electrode interface. The constructed sensor showed a broad linear detection range of 10–160 μM, high detection sensitivity reaching 0.226 μA·μM −1 , and a detection limit as low as 0.486 μM (S/N = 3) at the optimized working conditions. Besides, the developed sensor exhibited outstanding selectivity, stability, reproducibility, and repeatability. By determining the Qu content in Flos Sophorae Immaturus samples, we further confirmed the actual application capability of the constructed sensor. Satisfactory recoveries of 97.01%–101.08% were obtained, which strongly validated the reliability and accuracy of the proposed electrode for practical Qu analysis.