Abstract:

Molecularly imprinted polymeric microspheres (MIPMs) had been prepared by a one-step swelling polymerization method in aqueous system using micron-polystyrene microspheres which was gained by emulsifer-free polymerization as seeds and using Chlorpyrifos as template molecules. The selective binding characteristics of MIPMs were evaluated by ultraviolet spectrometry. The infrared spectrometry(IR) of the polymer further indicated that there were some functional groups in the moleculary imprinted polymer which could interact on the template. Subsequent morphological characterizations of the MIPMs by scanning electron microscope (SEM), show that they diameters were between 0.5～3μm(as opposed to 2～3μm for the UMIPMs), surface rugosity and high porosities with pore, it was facility related to the template and binding sites , so to obtain a high load, affinity and selectivity to template molecules. Scatchard analysis suggested the MIPMs recognizing Chlorpyrifos with two classes of binding sites. The calculated dissociation constant KD1 and apparent maximumnumber Bmax1 of binding siteswith high affinity were 0.526 mmol/L and 35.91 μmol/g respectively, while KD2 and Bmax2 of binding siteswith low affinity were 2.19 mmol/L and 83.87 μmol/g.

Key words: Molecularly imprinted polymeric microspheres, Single-step swelling polymerization, Chlorpyrifos, Binding sites