Extraction of Catechin as a Flavonoid Compound via Molecularly Imprinted Polymers

The aim of this study is synthesis of molecularly imprinted polymers (MIPs) and evaluation for extraction of catechin. Catechin is a bioactive compound which is found abundantly in green tea. In this paper, MIPs was synthesized by precipitation polymerization technique for catechin, acrylic acid and trimethylolpropane trimethacrylate as a template, functional monomer and cross-linker in a molecular ratio of (۱:۱۲:۱۲), respectively. Surface morphology in the MIPs by scanning electron microscopy (SEM) demonstrated spheres with nanometric scale. Fourier transform infrared spectroscopy (FTIR) of the polymers showed that catechin molecule was captured in the network copolymers. Porosity of the polymers were analyzed using Brouneur Emmet Teller (BET) technique. Based on BET analysis, specific surface area of the MIPs was ۴۵.۵ m۲.g-۱ while it was ۴۲.۲ m۲.g-۱ for non-imprinted polymers (NIPs). It means that the imprinting process was carried out successfully. Adsorption properties of the polymers were characterized too.  The best binding capacity of the MIPs was reported equal to ۴۴۰ mg. g-۱ in ۷۵۰ ppm of the feed concentration whereas it was ۸۴mg.g-۱ for quercetin (similar structure of catechin). It confirms that the MIPs technology can be introduced as a good candidate for separation process with a satisfactory result in selectivity. The binding capacity of the MIPs was evaluated for natural extract of green tea using a high-performance liquid chromatography (HPLC) device which similar results were obtained. According to above mentioned results, separation and pre-concentration of the bioactive compounds from the extract of medicinal plants can be suggested via MIPs technique.

Keywords:

catechin , Molecularly imprinted polymers , Selectivity , Green tea , Separation , Bioactive