Quercetin (3,5,7,3′,4′-pentahydroxyflavone), which belongs to theclass of bioflavonoids, is an important flavonoid, which is also an indispensable component of the human diet, with fruits, leafy and dried vegetables [1,2]. Ability ofquercetin for scavenging free radicals and binding transition metal ionsallow it to inhibit reducing oxidative stress and associated damages.Therefore, quercetin is often suggested as a main flavonol for antioxidant therapy [3]. Many different analytical methods have been described for the extraction and determination of quercetin. Herein, mesoporous silica–Fe3O4–graphene oxide (Fe3O4/GO@mSiO2) adsorbent was synthesized. More importantly, the adsorption ability of Fe3O4/GO@mSiO2 magnetic nanoparticles to extract quercetin from aqueous solutions was investigated. Initially, graphene oxide nanoparticles were synthesized via Hammer method. After that the GO magnetized by FeCl3.6H2O and FeCl2.4H2O. Furthermore, Modified by mesoporous silica. The magnetic nanoparticles Fe3O4/GO@mSiO2 was used to measure quercetin in four real samples (spinach, green pepper, dill and red onion). Fe3O4/GO@mSiO2 nanoparticles was characterized by Fourier transform infrared (FT_IR), scanning electron microscopy (SEM), X-ray diffraction (EDAX), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and X-ray photoelectron spectroscopy (XPS). The Fe3O4/GO@mSiO2 strategy revealed a great stability and a superb sensitivity for quercetin measurements, with a suitable linear range 0.8-0.02 ppm and a detection limit 5.24 micrograms per milliliter. The data indicate that Fe3O4/GO@mSiO2 has a specific surface and the maximum adsorption capacity for measuring quercetin.
