Amperometric Determination of Quercetin in Some Foods by Magnetic Core/Shell Fe3O4@ZnO Nanoparticles Modified Glassy Carbon Electrode

In this paper, Fe3O4@ZnO core/shell magnetic nanoparticles (MNPs) have been synthesized by a simple method, to modify carbon paste/glassy carbon electrode and improve its efficiency for determination of quercetin. The synthesized MNPs were characterized by X-ray powder diffraction (XRD), transmission electronic microscope (TEM), and scanning electronic microscope (SEM). SEM and TEM results show that the prepared Fe3O4@ZnO MNPs are made of the spherical shape particles with an average size of about 15 nm. The electrochemical behavior of quercetin at the surface of modified electrode was investigated. Under the optimal conditions, a linearity range of quercetin was 7.9 x 10(-7) to 6.1 x 10(-5) mol/L (0.24-18.44 mg/L) with detection limit (S/N = 3) and sensitivity of 0.16 mu mol/L (0.048 mg/L) and 0.04 mu A/mu M, respectively. The validated method was applied successfully for determination of quercetin in some foods and human breast milk.