Hydophilic Interaction Chromatography (HILIC) is used for the separation of polar and hydrophilic compounds. Stationary phases are polar, similar to normal phase chromatography (NPC).
Typical HILIC phases are silica or polymer particles carrying polar functional groups. Mobile phases are aqueous buffers with organic modifiers applied in isocratic or gradient mode.
The aqueous content of the mobile phase in HILIC creates a water rich layer on the surface of the stationary phase.
This allows partitioning of solutes between the more organic mobile phase and the aqueous layer.
The number of polar groups and the conformation and solubility of the sample in the mobile phase determine the elution order. Compared to reverse phase chromatography (RPC) the elution order in HILIC is inversed for most compounds.
HILIC is ideally suited for mass spectrometric analysis of water soluble polar compounds, because the high organic content in the mobile phase increases MS detection sensitivity.