Theoretical design and selectivity researches on the enrofloxacin imprinted polymer

Abstract

In this paper, enrofloxacin (ENRO) was chosen as the template molecule, 4-vinylpyridine (4-Vpy), acrylamide (AM), trifluoromethacrylic acid (TFMAA), and 2-hydroxyethyl methacrylate (HEMA) were selected as the functional monomers, with the following cross-linking agents, ethylene glycol dimethacrylate (EDMA), pentaerythritol triacrylate (PETA), and trimethylolpropane trimethacrylate (TRIM). The stable complex configurations formed by ENRO and four monomers at the molar ratio of 1:1 were calculated using the density functional theory at the B3LYP/6-31G(d,p) level. Their natural bond orbital charges and the action sites were discussed to screen the appropriate functional monomer. The optimal molar ratio of template–monomer complex and the effects of cross-linking agent were investigated. The nature of the imprinting interaction was also researched via the infrared spectrum. The results reveal that the complex formed from ENRO and TFMAA has the strongest hydrogen bond interaction. When the molar ratio is 1:7, the complex has the most stable configuration. Owning to the weakest interaction between EDMA and ENRO, and the strongest interaction between EDMA and TFMAA, EDMA is considered as the suitable cross-linking agent, in comparison with PETA and TRIM for ENRO-MIPs. After the removal of ENRO molecule, the most stable ENRO-TFMAA complex owing to the better binding capacity to ENRO is compared with its structural analogues (ciprofloxacin, sparfloxacin, pefloxacin, ofloxacin, and sarafloxacin). This study provides a reliable theoretical guidance for the preparation of new ENRO-MIPs.