Development of a Magnetic Solid-Phase Extraction-Liquid Chromatography Targeted to Five Fluoroquinolones in Food Based on Aptamer Recognition

Fluoroquinolones (FQs) are present in trace amounts in the environment, from where they enter animal- and plant-derived food products. Long-term exposure to low-dose drugs poses a risk to human health and increases the pressure on antibiotic selection. Based on previous aptamer screening with high FQs specificity, this study combined a new aptamer recognition probe with a metal-organic framework (MOF) to obtain a sample pretreatment composite material with strong FQs specificity for multi-target analysis. Residual FQs were extracted from the complex food matrix via magnetic dispersive solid-phase extraction and examined using high-performance liquid chromatography. The method showed good linearity in a range of 0.39 to 200 µg/kg for five FQs in milk and fish samples, with a detection limit of 0.04-0.10 µg/kg and a quantitative limit of 0.13-0.33 µg/kg. This study successfully developed an effective sample pretreatment material and methodology for trace FQs identification in complex animal-derived food matrices.