Abstract:

A series of molecularly imprinting polymers (MIPs) at different ratios of template and functional monomer were prepared using phenolphthalein as template and 4-vinylpyridine as functional monomer. The surface features of the polymers were analyzed by scan electron micrographs. The static equilibrium binding experiments were performed to investigate the adsorption property and selective recognition of the MIPs for phenolphthalein and its analogues. It was shown that saturated adsorption was achieved in 3 hours. The best imprinting effect was observed when the molar ratio of the template molecules, functional monomer and crosslinker is 1∶6∶20. Scatchard analysis showed that two classes of binding sites were formed in the imprinted polymers in the concentrations range studied. The calculated dissociation constant Kd1 and apparent maximum binding capacities Qmax1for the high affinity sites are 0.63 mmol/L and 25.4 μmol/g, while Kd2 and Qmax2 for the low affinity sites are 3.5 mmol/L and 61.9 umol/g, respectively. The molecularly imprinting polymers displayed higher selectivity for phenolphthalein compared with the analogues of phenolphthalein.

Key words: phenolphthaleinf, molecularly imprinting polymers, preparation, specific adsorption