3,3′-Diindolylmethane imprinted polymers: synthesis, characterization and analytical procedure for template isolation from biological matrix

Abstract

A novel sorbent for the separation of 3,3′-diindolylmethane (DIM) has been developed. DIM was used as a template molecule to prepare twelve imprinted polymers from seven different functional monomers in six various porogens in the presence of ethylene glycol dimethacrylate as a crosslinker. The binding capacity showed that the highest binding specificity was achieved when allylamine as the monomer and carbon tetrachloride as the porogen were used to form bulk polymers. Binding capacities were 130.4 ± 2.8 µg g−1 for imprinted MIP7a polymer versus 49.03 ± 0.44 µg g−1 for non-imprinted NIP7a polymer. An imprinting factor of 3.12 reflected the high specificity of MIP7a. A solid-phase extraction protocol was fully optimized. Two methanol–water systems were selected as the most effective for loading and washing steps, while acetonitrile was chosen as the most efficient eluent suitable for recovery of 91.7 ± 3.8% of DIM. Optimal concentration of DIM and volume of loaded sample were also examined. A loaded volume of 2.5 mL was the most appropriate for 0.625 and 1.25 mg L−1. The use of MIP7a for the separations of DIM from spiked bovine serum albumin was evaluated, showing a total recovery of 87.7 ± 3.5%. The commercial sorbent C18 was not suitable for such an application. © 2013 Society of Chemical Industry