Synthesis and binding site characteristics of 2,4,6-trichlorophenol-imprinted polymers.

2,4,6-Trichlorophenol (2,4,6-TCP)-imprinted micro- and submicrospheres prepared by precipitation polymerization were compared with templated materials obtained by conventional bulk polymerization. The influence of the type and amount of functional monomer, the type and amount of cross-linker, polymerization temperature, porogen, and the ratio of template molecule and functional monomer to cross-linker on the size of the obtained particles were investigated. UV-Vis spectrophotometer experiments revealed that the microsphere polymers provided higher affinity to the template in contrast to imprinted polymers prepared by bulk polymerization. The binding properties of the microspheres, including binding isotherms and affinity distribution, were studied via Freundlich isotherm affinity distribution (FIAD) analysis. The obtained results indicated that microspheres prepared by precipitation polymerization provided superior rebinding properties during equilibrium binding in contrast to bulk polymers and submicrosphere polymers. Moreover, release experiments showed that 80% of rebound 2,4,6-TCP was released from the imprinted microspheres within the first 2 h, while more intimately bound 2,4,6-TCP molecules were released in the following 40 h. The morphologies and porosities of the resulting imprinted materials were characterized by scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis, respectively. The microsphere polymers exhibited a regular spherical shape with a high degree of monodispersity to the corresponding bulk polymers. Furthermore, the micro- and submicrospheres were characterized by narrow distribution of pores in contrast to a heterogeneity index of m = 0.6647 for the microsphere imprinted polymer.