Hydrophilic Interaction Liquid Chromatography (HILIC): A Review

Hydrophilic Interaction Liquid Chromatography (HILIC) is a type of normal phase chromatography that performs with a very polar stationary phase and a mostly organic mobile phase. Hydrophilic interaction is prominent once the mobile phase includes at least 60% organic solvent. The mechanism of HILIC involves partitioning between a water-enriched layer that is partially immobilized on the hydrophilic stationary phase and the less polar mobile phase. Instrumentally speaking, a chromatographic system for HILIC chromatography is virtually equivalent to an RPLC (Reversed Phase Liquid Chromatography) system. The stationary phase in HILIC columns is hydrophilic and frequently also charged, at least in some pH ranges. Compounds separated on the column interact with the stationary phase and are generally more strongly retained the more hydrophilic the compound. It is used to determine the concentrations of dimethindene maleate in topical gel, zanamivir in rat and monkey plasma, and tromethamine as the counterion in an investigational pharmaceutical salt.