Molecular-imprinted poly(methacrylic acid) was synthesized with a template of retinoic acid to separate retinoid derivatives. The suspension polymerization technique was used to prepare round microparticles for high-performance liquid chromatography (HPLC) packing column materials. The effects of the types and amounts of the dispersing agents and surfactants on the structure and size of the prepared molecular-imprinted-polymer particles were investigated. The separation of retinoic acid from its derivatives was more efficient when the perfluorocarbon dispersing agent was used instead of water, as the latter reduced the binding force between the objective molecules and monomers. HPLC separation features were also affected by the size and distribution of particles loaded in the column. A higher retention volume was obtained for smaller particles with a broader size distribution. (C) 2005 Wiley Periodicals, Inc.