Poly Phenyl is made of 80% cross-linking PS/DVB spherical particles bonded with phenyl functional group for hydrophobic interaction. The Poly-Phenyl comes with both non-porous and porous structures with the particle size from 1.7, 3, 5, to 10 µm and pore size from 100, 300, 500, to 1000 Å. Compared with silica based reversed phases, Poly-Phenyl phase bring wide pH stability from 1 to 14 for hydrophobic interaction separation of small molecules, peptides, oligonucleotides, and proteins.