Abstract: Areversed phase stationary phase of HPLCmade by covering a porous copolymer of ethyl-styrene with divinylbenzene on the surface of silica gel is reported.The encapsulated polymer packing material maintains the main advantages of both polymer and silica based material.it is not only chemically stable, ion-free, and not soluble in solvents, but also of high rigidity, and has compatibility for solvent changing from organic to aqueous and reverse.Such packing is easy to pack and has a high column efficiency.Its application to the separation of aniline derivatives is documented.

Key words: Polymer encapsulated stationary phase, Preparation and evaluation, Separation of aniline derivatives