Hydrophilic interaction liquid chromatography, or HILIC, is a powerful mode of liquid chromatography (LC) for the separation of polar analytes using polar stationary phases and high-organic initial mobile phase conditions.
HILIC-methods provide better retention of water-soluble compounds that have limited or no retention on typical reversed phases like C8 and C18. The solvents used in HILIC methods are similar to those employed in reversed-phase LC (e.g., water, methanol, and acetonitrile) and volatile buffers and modifiers may also be used.
In HILIC mode water is the “strong” or eluting solvent, opposite to reversed-phase LC, where water is the “weak” solvent. In HILIC separations, the initial conditions are highly organic (typically 60% or more) and a water layer is adsorbed on the silica surface.
The polar analytes are soluble in the water layer, can interact with the polar particle surface and are retained in multiple ways (hydrogen bonding, dipole-dipole, and ion exchange). To elute the polar analytes from the polar stationary phase the amount of water is increased. The water layer is formed by diffusion, which can be slow. For reproducible results the water layer must be identical in every run.
Join Restek as they explore HILIC separations for liquid chromatography in this quick-hit video:
Plus, visit the Restek site to learn more about the HILIC method and how to successfully incorporate it into your laboratory’s repertoire.
