Which chromatography method involves the separation of molecules based on their hydrophobicity?

Hydrophobic Interaction Chromatography is distinguished by its specific mechanism of separating molecules based on their hydrophobic properties. In this method, proteins or other biomolecules are typically applied to a column that contains hydrophobic ligands. As the mobile phase (often a buffer solution) gradually changes in salt concentration, hydrophobic interactions become more pronounced, promoting the binding of hydrophobic regions of the molecules to the hydrophobic stationary phase. This allows for effective separation, as molecules with varying degrees of hydrophobicity will elute at different times based on their interactions with the stationary phase.

This method is particularly useful in protein purification and is employed to isolate proteins in a way that preserves their biological activity, which is crucial in bioscience applications. As a result, it represents a key technique in biochemistry and related fields where the properties of molecules dictate their behavior in chromatography.