Electrochemical quercetin sensor based on a nanocomposite consisting of magnetized reduced graphene oxide, silver nanoparticles and a molecularly imprinted polymer on a screen-printed electrode

An electrochemical quercetin (QR) sensor is described that is based on the use of magnetic reduced graphene oxide (MrGO) incorporated into a molecularly imprinted polymer (MIP) on the surface of a screen-printed electrode (SPE). The MrGO consists of reduced graphene oxide (rGO), magnetite (Fe3O4) and silver nanoparticles (Ag). The analyte (QR) is electrostatically adsorbed on the surface of the MrGO. Finally, the MIP was deposited via in-situ polymerization. The composite was characterized by Xray diffraction, Fourier transform infrared spectroscopy and Vibrating sample magnetometry. The morphologies and electrochemical properties of different electrodes were characterized by Field emission scanning electron microscopy, Electrochemical impedance spectroscopy and differential pulse voltammetry. Under optimal conditions, the modified electrode has a linear response in the 20 nM to 250 mu M QR concentration range. The limit of detection is 13 nM (at an S/N ratio of 3). The electrode is selective, stable, regenerable and reliable. It was applied to the determination of QR in spiked pharmaceutical samples and gave satisfactory results.