An ion-exchange monomer including an anion exchange group and a cation exchange group, 2-methacryloyloxyethylphosphoryl choline (MPC) was introduced on the surface of uniformly sized, hydrophilic macro-porous polymer particle. We carefully studied several solvents utilized for the surface modification to elucidate solubility of the monomer as well as its polymer into each solvent. Based on the change in existing form of poly-MPC modified on the surface of stationary phases, ion-exchange properties of poly-MPC were controllable to result in interesting selectivity changes in HPLC.