Developing rapid and efficient analytical methods is of great importance for food safety Herein, we present a novel homogeneous electrochemical aptasensor for ultrasensitive quantitative determination of zearalenone (ZEN) based on a nanocomposite probe and silica nanochannel film. X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and UV-Vis characterization techniques confirm that graphene oxide (GO) bears an aromatic conjugated structure, along with hydroxyl and carboxyl groups, facilitating the subsequent adsorption of cationic redox hexa-ammine-ruthenium (III) (Ru(NH3)63+) and anionic ZEN aptamer, to form a Ru(NH3)63+-ZEN aptamer-GO nanocomposite probe in a homogeneous solution. Vertically-ordered mesoporous silica films (VMSF) bearing silanol groups can be simply grown on the solid indium tin oxide (ITO) electrode surface and enable the selective preconcentration of Ru(NH3)63+, eventually leading to signal amplification. Since the detachment of Ru(NH3)63+ from the GO surface by the recognized ZEN aptamer in the presence of ZEN, more free Ru(NH3)63+ is released in solution and produces enhanced redox signals at the VMSF modified ITO electrode, allowing quantitative detection of ZEN. On the basis of the above sensing strategy, the proposed homogeneity, due to the assistance of graphene, as well as of the signal amplification and anti-fouling effects of VMSF, accurate analysis of ZEN can be realized in maize and Chinese chestnut samples.
Keywords: graphene oxide; homogeneous aptasensor; vertically-ordered mesoporous silica films; zearalenone.