Imprinting Sorbents
“Molecularly imprinted polymers (MIPs) have only recently been recognized as rugged, artificial recognition elements. MIPs have been prepared for a variety of small molecules with the affinity and specificity of the MIP for the target molecule approaching that observed for monoclonal antibodies. However, the preparation of MIPs for proteins and other large biomolecules have had limited success.”
“Mosbach and coworkers, as exemplified by U.S. Pat. Nos. 5,110,833 and 5,461,175, have developed what they call "molecular imprinting", which is a method of preparing polymers by polymerizing monomers around "print molecules". Molecular imprinting of synthetic polymers is a process where functional and cross-linking monomers are copolymerized in the presence of the target analyte, which acts as a molecular template. Before polymerization, the functional monomers either form a complex with the template via non-covalent interactions, or are covalently coupled forming a polymerizable derivative of the template. After polymerization, the functional groups of the monomers are held in position by the highly cross-linked polymeric structure. Subsequent removal of the template by solvent extraction or chemical cleavage reveals binding sites that are complementary in size and shape to the analyte. In this way, a molecular memory is introduced in the polymer, which is now capable of rebinding the analyte with very high specificity. “
Recent Journal Articles
Ion-imprinted PHEMA based monolith for the removal of Fe3+ ions from aqueous solutions
(1829–1836)Journal of Applied Polymer Science 120 #3 (2011)
Özkara et al of Hacettepe University and Anadolu University, Turkey prepared a molecular recognition based Fe3+ imprinted monolith for selective removal of Fe3+ ions from aqueous solutions. The precomplexation was achieved by the coordination of Fe3+ ions with N-methacryloyl-(L)-cysteine methyl ester (MAC) to form the complex monomer (MAC-Fe3+). The polymerization step was then carried out in the presence of MAC-Fe3+ complex and hydroxyethyl methacrylate (HEMA) monomer by bulk polymerization to constitude a Fe3+-imprinted polymer (PHEMAC-Fe3+). The PHEMAC-Fe3+ monolith was recovered and reused many times without any significant decrease in its adsorption capacity. (RDC 2/16/2011)
Synthesis of Zn(II) Ion-Imprinted Polymeric Adsorbent for Selective Removal of Zinc from Aqueous Solutions
(216 – 219) Polymer - Plastics Technology and Engineering 50 #2 (2011)
Özkahraman et al of Hitit University and Istanbul University, Turkey prepared the microbeads using methacrylic acid and 1,4-vinyl pyrrolidone as functional monomers, zinc(II)acetate as zinc salt, ethylene glycol dimethacyrlate as a cross-linking agent, azo bisisobutyronitrile as an initiator and hydroxyethyl cellulose as surfactant. According to the adsorption capacity values of the microbeads, Zn(II)-IIP beads show good selectivity for the target ion. (RDC 2/3/2011)
Adsorption properties of Cd(II)-imprinted chitosan resin
(1535-1541) Journal of Materials Science 46 #5 (2011)
Liu et al of the Ocean University of China, China showed the selectivity coefficient of Cd(II) and other metal cations on Cd-imprinted chitosan indicated an overall preference for Cd(II), which was much higher than that of non-imprinted chitosan resin. (RDC 1/12/2011)
Molecularly imprinted polymers synthesized via semi-covalent imprinting with sacrificial spacer for imprinting phenols
(5417-5423) Polymer 51 #23 (2010)
Qi et al of Chinese Academy of Science, China used the carbonyl group as sacrificial spacer to synthesize molecularly imprinted polymer for phenols. 4-chlorophenyl (4-vinyl)phenyl carbonate as template was the best imprinter, with ethylene glycol dimethacrylate (EGDMA) as cross-linker, 2,2-azobisisobutyronitrile(AIBN), and chloroform as initiator and porogen, respectively. The polymer prepared by semi-covalent imprinting displayed superior selectivity to the non-covalently imprinted polymer for phenols. (RDC 12/17/2010)