Determination of Fluoroquinolones in Milk by High-Performance Liquid Chromatography Using Mixed-Templates Imprinted Polymer Extraction

Abstract

A high-performance liquid chromatography-diode array detection method (HPLC-DAD) for the determination of fluoroquinolone antibiotics in milk has been developed using molecularly imprinted polymer solid phase extraction (MISPE). The molecularly imprinted polymer (MIP) has been prepared using levofloxacin and ciprofloxacin as the templates. The imprinted polymer has been characterized by equilibrium binding experiment to investigate the binding ability to template molecule. Various parameters affecting the extraction efficiency of the polymer in the MISPE procedure have been evaluated to achieve optimal preconcentration. The fluoroquinolones are extracted from milk with 2 % acetic acid in acetonitrile, purified on the MISPE cartridge and then analyzed using HPLC-DAD set at 281 nm. The method has been validated by analyzing spiked milk samples at two levels (100 and 200 μg kg^-1), the mean recoveries of the method range from 84.1 to 104.7 % with relative standard deviation no more than 4.3 % (n = 3) for fleroxacin, enoxacin, pefloxacin, norfloxacin, ciprofloxacin, levofloxacin, lomefloxacin, enrofloxacin, gatifloxacin and sparfloxacin. The method detection limits range between 1.34 and 7.35 μg kg^-1. The method was demonstrated to be suitable for the sensitive and accurate quantification and confirmation analysis of fluoroquinolones.