Selective adsorption of D- and L-phenylalanine on molecularly-imprinted polymerized organogels formed using polymerizable gelator N-octadecyl maleamic acid

The polymerizable gelator N-octadecyl maleamic acid (ODMA) can self-assemble in selected polymerizable organic solvents, such as 2-hydroxyethyl methacrylate (HEMA) and methylacrylic acid (MAA) to form thermally stable polymerizable organogels. A mixture consisting of HEMA and MAA as the monomer and functional monomer, PEG dimethacrylates (PEG200DMA) as the crosslinker, BOC-L-phenylalanine (BPA) or L-phenylalanine ethyl ester (PEE) as the chiral templates, was gelatinized by ODMA firstly and subsequently polymerized by in situ UV irradiation or thermal initiation. The molecularly imprinted polymerized organogels were obtained after the removal of the templates through ethanol extraction. Selective adsorption of D- and L-phenylalanine was performed on the polymerized organogels. The results indicate rather high adsorption efficiency obtained for L-phenylalanine compared with that for D-phenylalanine, which was found to be dependent on the concentrations of ODMA, content of template, and the method of polymerization. Herein, the concentration of ODMA in the organogels played an important role for the adsorption efficiency of D- and L-phenylalanine.