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

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 pregraft 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-p 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.