Determination of Fluoroquinolone Residues in Aquatic Products by Dispersive Solid Phase Extraction with Metal-Organic Framework-Based Molecularly Imprinted Polymer and Liquid Chromatography-Tandem Mass Spectrometry

A novel adsorption material for dispersive solid phase extraction (DSPE) was prepared using amino-functionalized zirconium-based metal-organic framework (UiO-66-NH₂) as the core and molecularly imprinted polymer as the shell. Subsequently, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the material. Key experiential parameters such as solvent, adsorbent concentration, adsorption time, desorption solvent and time were systematically investigated. Furthermore, a highly sensitive method for the determination of fluoroquinolone residues in aquatic products was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with DSPE. The extract was blown to near dryness under nitrogen and re-dissolved with 10% methanol-ammonia solution (pH 8.0). Subsequently, 30 mg of the adsorbent was added for adsorption for 8 minutes. Next, the fluoroquinolones sorbed were ultrasonically desorbed with 10% acetic acid-methanol solution for 4 minutes, blown to near dryness under nitrogen and re-dissolved before analysis by LC-MS/MS. Good linearity was observed all 10 fluoroquinolones in the concentration range of 0.1–200 μg/L, with recovery rates of 84.5%–105.9%. Compared with the national standard method, the established method had higher accuracy, lower limit of detection (LOD) and limit of quantification (LOQ), simpler and more efficient operation. The new material had good selectivity and reusability, effectively reducing the cost of detection. This study helps expand the application scope of metal-organic framework-based molecularly imprinted polymers in food safety detection.