Hydrophobic interaction chromatography (HIC) is based on non-polar interactions that are induced by high salt mobile phases. Stationary phases are similar to reversed phase chromatography (RPC) but the density of functional groups is lower. A weakly non-polar stationary phase is used with an aqueous mobile phase containing a high concentration of a chaotropic salt.
The technique is mainly applied to the separation of proteins, which are eluted by decreasing the salt concentration or by adding a low percentage of organic solvent. Although also based on hydrophobic interactions, selectivity in HIC separations is distinctly different from that in reversed phase chromatography. Despite the lower peak capacity in HIC compared to RPC, HIC has the advantage that the mobile phase conditions (primarily aqueous) do not usually disrupt higher-order protein structures.
