Molecularly imprinted polymers for the selective recognition of l‐phenylalanine based on 1‐buty‐3‐methylimidazolium ionic liquid

Abstract

To enhance the affinity of 4-vinyl pyridine to L-phenylalanine (L-Phe) and convert the imprinting process from the aqueous phase to the organic phase, an oil-soluble amino acid ionic liquid was introduced as a template. In this study, 1-butyl-3-methylimidazolium a-aminohydrocinnamic acid salt was first applied to prepared surface molecularly imprinted polymers (MIPs) in acetonitrile for the selective recognition of L-Phe. Fluorescence quenching analysis of the functional monomer on the template was investigated under different conditions to study the imprinting mechanism. Several binding studies, such as the sorption kinetics, sorption thermodynamics, and solid-phase extraction application, and the chiral resolution of racemic phenylalanine were investigated. The binding isotherms were fitted by nonlinear regression to the Freundlich model to investigate the recognition mechanism. The affinity distribution analysis revealed that polymers imprinted by ionic liquid showed higher homogeneous binding sites than those imprinted by L-Phe. The competition tests were conducted by a molecularly imprinting solid-phase extraction procedure to estimate the selective separation properties of the MIPs for L-Phe. The target MIP was shown to be successfully for the separation of L-Phe from an amino acid mixture.

Highly selective recognition of L‐phenylalanine with molecularly imprinted polymers based on imidazolyl amino acid chiral ionic liquid

“…In previous research, the adsorption amount obtained for the L‐Phe‐imprinted polymers prepared with ILs was about 11 and 33 mg, respectively, while the adsorption amount of L‐Phe@MIPs prepared in this experiment was about 62 mg/g. Therefore, we can conclude that the L‐Phe@MIPs exhibited certain advantages in terms of adsorption amount.…”

“…Sergey et al found that the imprinted polymers prepared with 2‐(trifluoromethyl acrylic acid) as the copolymer and D‐phenylalanine as the template molecule exhibited an enantio‐separation factor of 1.19. And MIPs have been tried for the separation of D‐Phe and L‐Phe in recent years . However, these imprinted polymers exhibited relatively low adsorption capacity or poor selectivity to target molecules.…”

“…Compared with reversible covalent imprinting, the noncovalent imprinting is more widely applied in the presence of porogens . Additionally, the use of ionic liquids (ILs) as functional monomers was reported to enhance the selectivity and adsorption performance of imprinted polymers . For example, L‐Phe‐imprinted polymers were prepared with [VCIM]Cl as functional monomer, and the maximum adsorption capacity to L‐Phe was 33.08 mg/g.…”

“…Moreover, they have excellent compatibility with some compounds because of the good solubility in various organic solvents. Due to the hydrogen‐bonding interactions between the template and monomer, the use of amino acid ionic liquids as functional monomers may increase the adsorption capacity of MIPs to L‐Phe . Besides, the presence of metal ions may enhance the interaction between molecules.…”

Chiral Ionic Liquids: Structural Diversity, Properties and Applications in Selected Separation Techniques

“…Yang et al [174] presented a very promising feature of ionic liquids as solvents in molecular imprinting technology (MIT), which is useful in the isolation or purification of analytes on large scale. MIT uses the interactions based mainly on hydrogen bonding between the template and the monomer.…”