Abstract: A novel packing material is provided for liquid chromatographic columns, having a maximum pore size around 80 angstroms, a hydrophobic coating on the inner surfaces adapted to absorb hydrophobic analytes, and a hydrophilic coating on the outer surfaces adapted to reject proteins in the analyte sample. A novel method is provided for making the packing material, wherein the packing base is coated, inside and out, with a hydrophilic substance, a hydrophobic substance is bonded to the hydrophilic substance, and the hydrophobic substance is selectively removed from the external surfaces by treatment with an enzyme of a size too large to penetrate into the pores.