Analysis of Trace Enrofloxacin in Environmental Waters by a Surface Molecular Imprinting Technique

Surface-imprinted polymers (ZIF-67@MIPs) supported by ZIF-67 were prepared by precipitation polymerization using enrofloxacin (ENR) as the template molecule, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as the cross-linker. ZIF-67@MIPs were characterized by Fourier transform infrared spectrometry, X-ray diffraction, scanning electron microscopy, and particle size distribution. The adsorption performance of the polymer was studied. The adsorption equilibrium was reached within 30 min. The maximum adsorption was 9.02 μg·mg^-1. The imprinting factor was 2.58. The polymer was then used as a sorbent of a solid-phase extraction column for the separation and purification of ENR in real water samples. The extraction conditions were optimized. The method was established by high-performance liquid chromatography, and the linearity was verified by UPLC-MSMS. The correlation coefficient and limits of detection and quantification were 0.9999, 0.23 ng·mL^-1, and 0.76 ng·mL^-1, respectively. The recoveries were in the range of 83.79-100.68%; the relative standard deviation was 4.46-7.35%. The above data indicated that the method could be used for the separation and enrichment of ENR in real samples.