Utilization of theoretical studies of the imprinting ratio to guide experimental research into the molecular imprinted polymers formed using enrofloxacin and methacrylic acid.

Abstract

Computational approaches have been suggested as rational and fast methods for optimizing imprinting ratios. The B3LYP/6-31 g(d,p) level was applied to simulate the self-assembled system of molecularly imprinted polymers (MIPs) formed by enrofloxacin (ENRO) and methacrylic acid (MAA). Geometry optimization, the bonding situation, and the binding energies involved were studied to determine the impact of varying the imprinting ratio on the recognition characteristics. These theoretical results showed that the compound with an ENRO:MAA ratio of 1:7 had the lowest binding energy and the most stable structure. MIPs with different imprinting ratios of ENRO to MAA were then prepared in order to study the binding capacities of the polymers experimentally. The experimental and theoretically calculated results for these polymers were found to be consistent with each other. In dynamic adsorption experiments on the MIPs, the adsorption reaction was observed to reach a balanced state after 120 min. Analysis of the Scatchard plot revealed that the dissociation constant (K d) and the apparent maximum binding capacity (Q max) of MIPs with high-affinity sites were 451.67 mg/L and 42.23 mg/g, respectively, whereas the dissociation constant and apparent maximum binding capacity of MIPs with low-affinity sites were 883.39 mg/L and 73.15 mg/g, respectively. The quantity of ENRO adsorbed onto the MIPs was considerably higher than the quantities of ciprofloxacin (CIP) and ofloxacin (OFL) adsorbed, indicating that these MIPs have a much higher specific absorption capacity than the corresponding non-imprinted polymers.