Narrowly dispersed molecularly imprinted microspheres prepared by a modified precipitation polymerization method

A modified precipitation polymerization (MPP) method was established to prepare narrowly dispersed molecularly imprinted polymeric microspheres. MPP was stabilizer and surfactant free and needed only small amount of porogen (about 50 wt.%). Only part of alcohols and all the alkanes tested formed particles. Using a mixture of alkane and toluene as porogen, the carbon numbers of alkanes and solubility parameter of porogenic solvents were important factors in controlling particle morphology. Nearly mono-dispersed microspheres with diameter of about 2-3 μm were synthesized by MPP using mineral oil:toluene = 2:3 as porogen. Template did not affect the formation of globe microspheres in MPP. Microspheres prepared under the lowest reaction temperature had the highest binding capability. When used as sorbents of high performance liquid chromatography (HPLC), the microspheres prepared by MPP using bisphenol A, estradiol, and tebuconazole as template had similar binding selectivity and higher binding capability compared to microspheres synthesized by classical precipitation polymerization. Photoinitiation and low reaction temperature were important factors attributed to better binding capability of microspheres prepared by MPP.