Abstract: Aptamer-functionalized Fe3O4 nanoparticles/graphene oxide (Apt/Fe3O4/GO) was synthesized by the chemical co-precipitation method for use as a sorbent for magnetic solid-phase extraction (MSPE). The prepared material was characterized using various techniques such as Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and X-ray photoelectron spectroscopy (XPS) to demonstrate the successful preparation of Apt/Fe3O4/GO. Subsequently, an ultra-high performance liquid chromatography with fluorescence detection (UPLC-FLD) method was established for the detection of zearalenone (ZEN) in corn and wheat samples after MSPE using Apt/Fe3O4/GO. Important operating parameters including sample pH, extraction time, and desorption conditions were optimized. The results indicated that under optimized conditions, the pretreatment procedure was achieved within 11 minutes. The established MSPE-UPLC-FLD method showed a good linear relationship in the concentration range of 8.0–1 000.0 ng/mL, with a detection limit (LOD) of 2.64 ng/mL. The recoveries for actual samples ranged from 88.2% to 101.8%. After 8th repeated use, the recovery remained at around 80.5%. In conclusion, Apt/Fe3O4/GO combines the magnetic advantages of Fe3O4/GO and the recognition ability of aptamers, significantly improving the detection efficiency, sensitivity, and selectivity of ZEN. This composite holds great application value in food analysis.

Key words: aptamer; Fe3O4; graphene oxide; zearalenone; ultra-high performance liquid chromatography; magnetic solid phase extraction