Dual function AgNPs@UiO-66 based ratiometric electrochemical sensor for rapid and sensitive determination of luteolin in plants

Luteolin is a variety of bioactive flavonoids, it is of great significance to quickly and accurately determine the content of luteolin. This paper established a simple and rapid ratiometric electrochemical sensor for the sensitive determination of luteolin. Nano-flowering zirconium-based metal-organic frameworks (UiO-66) were synthesized and silver nanoparticles (AgNPs) were directly grown on the surface of UiO-66 to prepare AgNPs@UiO-66 composites. Then, AgNPs@UiO-66 was drop-coated on the electrode surface to prepare the ratiometric electrochemical sensor. AgNPs@UiO-66 has the dual function of providing a stable internal reference signal and enhancing the electrochemical signal. Under optimal conditions, the peak current of luteolin (ILuteolin) increased with increasing luteolin concentration, while the peak current of AgNPs@UiO-66 (IAgNPs@UiO-66), which is used as an internal reference signal, remained relatively stable. ILuteolin/IAgNPs@UiO-66 showed a good linear relationship in the range of 0.07 - 0.9 mu M and 0.9 - 40 mu M, and the limit of detection (LOD) was 0.017 mu M (S/N = 3). The sensor detected luteolin in peanut shells with recoveries ranging from 96.7 % to 107 %, which agreed with ultraviolet-visible spectroscopy. These results demonstrate the possibility of this ratiometric electrochemical sensor for detecting luteolin in real life.