Molecular imprinted polymer (MIP) microbeads were prepared by emulsion copolymerization of divinylbenzene (DVB) and methacrylic acid (MAA) in the presence of inosine (INO) template and laurylbenzenesulfonic acid (LBSA) as surfactant. The polymerization was carried out at 55 degrees C under ultrasound exposure. The resulting copolymer microbeads, having 0.1-0.4 mu m diameter, were observed to have a binding behavior of INO and surfactant to the polymer which was strongly dependent of the bulk pH; for example, at pH 3, 6, and 10 values of binding for INO to the imprinted copolymer were 3.7 mu mol/g, 2.1 mu mol/g, and 0 mu mol/g, respectively. It was found that LBSA surfactant bound to the MIP microbeads similarly depending on pHs. At pH 3, 6, and 10, the LBSA values of binding were 23 mu mol/g, 1.3 mu mol/g, and 4.8 mu mol/g. It was also noted that the surfactant binding was enhanced in the presence of the INO template. This demonstrated that a cooperative binding with the surfactant was cooperatively occurred in the presence of INO. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 565-571, 2010