Retain tertiary structure and biological activity.

• Columns are silica-based materials that operate through hydrophobic interactions (HIC)

HIC materials separate proteins on the basis of hydrophobic character, as does RPC. However, HIC uses totally aqueous buffers, retaining tertiary structure and biological activity. Selectivity is generally superior to that of RPC for proteins and polypeptides large enough to have significant secondary or tertiary structure. Typically, a sample is eluted with a decreasing gradient of a salt such as a sulfate or phosphate. Proteins elute in order of increasing surface hydrophobicity.