Designing and preparation of ferulic acid surface-imprinted material and its molecular recognition characteristics

Abstract

Ferulic acid (FA) is a phenolic acid with a styrene-type structure, which has many important bioactive and pharmacological functions. In this study, due to the presence of a polymerizable double bond in FA, FA surface-imprinting was realized successfully by adopting a new surface imprinting technology of “pre-graft polymerization and post-cross-linking/imprinting”. Dimethylaminoethylmethacrylate (DMAEMA) was first graft-polymerized onto the surface of micron-sized silica gel particles via surface initiated graft-polymerization to obtain the grafted PDMAEMA/SiO₂ particles, and then FA surface-imprinting was successfully carried out using dibromohexane as a crosslinker to obtain the FA surface-imprinted MIP-PDMAEMA/SiO₂ material. This imprinting process completely avoided the problem that the polymerizable double bond in FA takes part in the polymerization reaction. The binding and recognition characteristics of the MIP-PDMAEMA/SiO₂ particles towards FA were investigated using a batch method, column method and competitive adsorption method. The experimental results show that in an acidic solution, there are strong interactions between the PDMAEMA/SiO₂ particles and FA, and they involve electrostatic interaction as the main driving force and cation–π interactions as well as hydrogen bonding, constituting a supermolecular system. On this basis, FA surface-imprinting was smoothly performed. The surface-imprinted MIP-PDMAEMA/SiO₂ particles have special recognition selectivity and excellent binding affinity for FA. The selectivity coefficients of the MIP-PDMAEMA/SiO₂ particles for FA relative to chlorogenic acid and caffeic acid, which were used as two contrast phenolic acid compounds, were 6.47 and 2.75, respectively. The binding capacity of the MIP-PDMAEMA/SiO₂ particles for FA reaches up to 142 mg g⁻¹. The MIP-PDMAEMA/SiO₂ particles still have excellent elution property, which is convenient for their reuse.