Specific extraction of ciprofloxacin from milk by magnetic molecularly imprinted polymers

In this study, core-shell magnetic molecularly imprinted polymers (MMIPs) were rationally designed using Fe 3 O 4 @SiO 2 nanoparticles as carriers for selective recognition and extraction of ciprofloxacin (CIP) in milk matrices. Compared with the reported molecularly imprinted polymers, The synthesized MMIPs demonstrated exceptional magnetic responsiveness enabling rapid solid-liquid separation. Static and dynamic adsorption studies revealed a maximum CIP adsorption capacity of 11.64 mg/g, Scatchard model analysis identified two distinct binding sites: high-affinity and low-affinity sites. Pseudo-second-order kinetics indicating chemisorption-dominated binding. Moreover, selective adsorption experiments confirmed high specificity toward CIP adsorption, with no significant interference from structural analogs. Coupled with HPLC-DAD, the method achieved sensitive detection of CIP with limits of detection (LOD) and limits of quantification (LOQ) values of 0.86 g/L and 2.6 g/L, respectively. In the practical application of commercial samples, the recovery rate was 84.11–99.11 %, and the precision (RSD)was 0.5–1.21 %, demonstrating robustness for CIP enrichment in complex milk products.