Preconcentration of the antibiotic enrofloxacin using a hollow molecularly imprinted polymer, and its quantitation by HPLC

Hollow molecularly imprinted polymers (h-MIPs) consisting of K2Ti4O9 as a sacrifice matrix were synthesized for selective recognition of enrofloxacin (ENR). The h-MIPs possess a characteristic nanostructure and were characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction and transmission electron microscopy. The h-MIPs have a fast adsorption kinetic (similar to 10 min), high adsorption capacity and a good selectivity factor (2.4) for ENR. Following adsorption of ENR, it was eluted from the sorbent with methanol-acetic acid (8:2) and quantified by HPLC. The calibration plot extends from 0.5 to 16.0 ng mLaEuro3/4(1) of ENR with a correlation coefficient of 0.9912, and the limit of detection is 0.24 ng mLaEuro3/4(1) (at an S/N ratio of 3). The method was applied to the determination of ENR in spiked fish samples, and recoveries ranged from 68.88 to 100.29 % with relative standard deviations (for n = 3) between 1.6 and 4.4 %.