Aptamer-functionalized magnetic graphene oxide for high-efficiency magnetic solid phase extraction of six aflatoxins from food matrices.

This study reports the synthesis of a novel aptamer-functionalized magnetic graphene oxide adsorbent (AP/MGO) via a facile method for the efficient enrichment of six aflatoxins (AFs), which are highly toxic contaminants posing a significant threat to food safety and public health. This composite material synergistically integrates the high specific surface area and mass transfer properties of MGO with the molecular specificity of aptamers, enabling rapid magnetic solid-phase extraction (MSPE) for the selective isolation of target analytes from food matrices. This design seamlessly facilitates subsequent analysis via Ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis. Characterization confirmed the successful fabrication of AP/MGO, which exhibited a high adsorption capacity for AFs (45.03-58.12 mg/g), driven predominantly by π-π stacking, hydrogen bonding, and specific aptamer-target interactions. In validation studies, the adsorbent demonstrated excellent performance with high selectivity for AFs, validated against a panel of four other mycotoxins. The developed UPLC-MS/MS method exhibited excellent linearity for all six target aflatoxins over the concentration range of 0.01-100 μg/kg, with coefficients of determination (R2) consistently exceeding 0.9980. Furthermore, the method achieved low limits of detection (LODs) for the AFs, ranging from 0.0029 to 0.0077 μg/kg and satisfactory recoveries (67.25%-92.17%), indicating high sensitivity and accuracy. Collectively, this novel aptamer-functionalized adsorbent provides a robust and versatile platform for the trace-level analysis of hazardous substances in complex matrices and demonstrates significant potential for its application in routine monitoring and risk assessment of hazardous mycotoxins in complex food matrices. ENVIRONMENTAL IMPLICATION STATEMENT: Aflatoxins are highly toxic carcinogens that pose a significant threat to global food safety and public health. This study presents a novel AP/MGO adsorbent for the efficient removal and ultrasensitive detection of six major aflatoxins from complex matrices like milk. The material's high adsorption capacity, rapid kinetics, and excellent selectivity offer a powerful tool for mitigating the risks associated with these hazardous contaminants. The developed MSPE-UPLC-MS/MS method provides a robust and reliable strategy for routine monitoring, supporting food safety surveillance and helping to protect public health from the adverse effects of mycotoxin exposure.