Molecularly imprinted polymer-based solid phase extraction combined high performance liquid chromatography for determination of fluoroquinolones in milk

Abstract

In this study, a method combining molecularly imprinted polymer-solid phase extraction (MIP-SPE) and high performance liquid chromatography was developed to determine the residues of fluoroquinolone drugs in milk. During the experiments, different templates, functional monomers, porogens and template/monomer ratios were evaluated. The norfloxacin based MIP capable of recognizing four fluoroquinolones (ciprofloxacin, norfloxacin, enrofloxacin and lomefloxacin) was used to prepare the SPE cartridge. The MIP-SPE cartridge showed high adsorption capacities (≥4520 ng) and high recoveries (≥96%) to the four drugs, and could be reused for at least fifty times. Then the four drugs were fortified into blank milk samples respectively to be analyzed. The limits of detection were in the range of 10–20 ng mL⁻¹ and the recoveries were in the range of 76.8–97.7% with coefficients of variation lower than 8.3%. Furthermore, the MIP-SPE cartridge showed a better purification effect than three commercial SPE cartridges. This is the first study reporting the use of norfloxacin based MIP-SPE for determination of fluoroquinolones in milk.