Restricted access material (RAM) is a kind of bi-functional materials with both properties of macromolecule exclusion and small molecule retention and separation.It can be used for direct HPLC injection in the biological or environmental sample analysis.To facilitate the efficient performance in the biological and environmental analysis, different RAM stationary phases have prepared by using controlled/living radical polymerization.Various formats of materials including inorganic/organic hybrid, spherical polymers and monolithic columns have been employed in the research.Different structures with certain functionalities in the small molecule separation have been created.