Imprinted metal-organic framework for selective extraction and determination of fluoroquinolone antibiotics in food samples

Abstract

Fluoroquinolone (FQ) contamination is a major food safety concern. Therefore, it is imperative to establish an efficient and sensitive method for detecting FQ residues in food. This study describes the synthesis of an imprinted metal-organic framework (MOF) via an in situ template self-assembly method using pipemidic acid as a dummy template for extracting FQs. The imprinted MOF exhibited superior specific recognition ability and a high selectivity towards FQs, making it a suitable adsorbent for molecular imprinted polymer based solid-phase extraction (MIP-SPE). Several extraction parameters, including adsorbent dosage, extraction time, pH, and elution solvent type, were optimised. Under the optimised conditions, a good linearity of the developed MIP–SPE–LC–MS method for the six FQs was obtained, with R² values of >0.9946 at concentrations of 0.5–50 μg L^-1 for milk and 0.5–50 μg kg^-1 for pork. The method had low detection limits (0.02–0.12 μg L^-1 for milk and 0.03–0.12 μg kg^-1 for pork). Moreover, satisfactory recoveries (70.2–113.6%), good repeatability (0.9–5.7%), and high precision (0.3–8.3%) were achieved for all the six FQs in milk and pork samples. This method is reliable and suitable for determining trace FQ residues in food samples, thereby contributing to the safety control of food industry.