Molecularly imprinted cryogel for L-glutamic acid separation

Abstract A molecular recognition based L ‐glutamic acid ( L ‐GLU) imprinted cryogel was prepared for L ‐GLU separation via chromatographic applications. The novel functional monomer N ‐methacryloyl‐( L )‐glutamic acid‐Fe 3+ (MAGA‐Fe 3+ ) was synthesized to be complex with L ‐GLU. The L ‐GLU imprinted cryogel was prepared by free radical polymerization under semifrozen conditions in the presence of a monomer‐template complex MAGA‐Fe 3+ ‐ L ‐GLU. The binding mechanism of MAGA‐Fe 3+ and L ‐GLU was characterized by Fourier transform infrared (FTIR) spectroscopy in detail. FTIR analyses on the synthesized MAGA‐Fe 3+ ‐GLU complex reveals bridging bidentate and monodentate binding modes of Fe 3+ in complex with the carboxylate groups of the glutamate residues. The template L ‐GLU could be reversibly detached from the cryogel to form the template cavities using a 100 mM solution of HNO 3 . The amount of adsorbed L ‐GLU was detected using the phenyl isothiocyanate method. The L ‐GLU adsorption capacity of the cryogel decreased drastically from 11.3 to 6.4 μmol g −1 as the flow rate increased from 0.5 to 4.0 mL min −1 . The adsorption onto the L ‐GLU imprinted cryogel was highly pH dependent due to electrostatic interaction between the L ‐GLU and MAGA‐Fe 3+ . The PHEMAGA‐Fe 3+ ‐GLU cryogel exhibited high selectivity to the corresponding guest amino acids (i.e., D ‐GLU, L ‐ASN, L ‐GLN, L ‐, and D ‐ASP). Finally, the L ‐GLU imprinted cryogel was recovered and reused many times, with no significant decrease in their adsorption capacities. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012