The use of molecularly imprinted polymer for selective extraction of (+)-catechin

Molecularly imprinted polymer (MIP) was prepared using acrylamide and ethylene glycol dimethacrylate (EDMA) as functional and cross-linking monomers, respectively. (+)-Catechin (C) was chosen as the template molecule and solvent acetonitrile as porogen. The polymer was investigated as solid-phase extraction (SPE) sorbent for the clean-up of organic extracts of green tea. Specific binding capacity of prepared MIP was evaluated by comparison of specifically and nonspecifically [on blank polymer (BP)] bound amounts of C. Different media were tested for this purpose: acetonitrile, methanol, and water and the results were compared. The best specific capacity (3.84 mug/100 mg of MIP) was obtained in acetonitrile, which was used as porogen. This solvent was chosen for the next evaluation of the binding capacity of polymer for the other six catechins that occur in green tea. The MIP showed good selectivity towards C in the presence of structurally related compounds. Next, several washing solvents were applied to the developed SPE procedure with the aim to obtain maximum recovery for C. Acetonitrile, water, and methanol, with different additions of acetic acid, were used for this purpose. It was observed that water and acetonitrile are suitable for washing out of interferences, and the best elution solvent was methanol without any presence of acid. Very good recovery (95%) for C was obtained using the developed molecularly imprinted SPE (MISPE) procedure. The results of the presented work show that prepared MIP can be used as SPE sorbent for the clean-up of methanol extract of green tea.