Preparation of hollow molecular imprinting polymer for determination of ofloxacin in milk
A porous hollow molecular imprinting polymer (MIPs) with ofloxacin (OFL) as template and SiO2 nanoparticle (250 nm) as sacrifice core was synthesized. Dibutyl isophthalate was used as plasticizer to strengthen the polymer shell in MIP preparation firstly, which was necessary to avoid breaking the shell. Infrared spectra and transmission electron microscopy were used to verify the successful synthesis of the hollow MIPs. The adsorption behavior of MIPs was evaluated by adsorption capacity, imprint factor and adsorption model. The MIPs could obtain the adsorption capacity of 147 mg g−1 to OFL in theory and imprint factor of 2.6 when the initial OFL concentration was 900 μg mL−1. The MIPs could adsorb not only OFL but other fluoroquinolone antibiotics (FQs), which was useful to analyze FQs together. At the same time, it hardly adsorbed other compounds with dissimilar structure. The MIPs were used as adsorbent to enrich the FQs from milk and good selectivity and enrichment ratios were obtained. Coupling with high performance liquid chromatography, the FQs in milk were determined with no more than 30 ng mL−1 of the limit of quantitation.