Is HILIC Permanently Changing the Scene for HPLC Separations?
The separation of polar and hydrophilic compounds can be a challenge. Hydrophilic interaction liquid chromatography has proven to be a solid alternative for such applications.
Hydrophilic interaction liquid chromatography (HILIC) is a powerful technique for the separation of polar and hydrophilic compounds. In HILIC one uses a column with a hydrophilic stationary phase and an eluent with water, buffer and a high ratio of water-miscible organic solvent. Today it is generally settled that the retention mechanism is mainly based on partitioning between a water enriched layer, formed on a polar stationary phase under semi-aqueous conditions and a less polar mobile phase. A typical HILIC application uses 50–95% acetonitrile in an aqueous buffer such as ammonium formate, ammonium acetate and/or their corresponding acids or bases, which all have good solubility in organic solvents. HILIC can be used with many detection techniques, but when combined with evaporative detection techniques, such as electrospray ionization mass spectrometry, evaporative light scattering or charged aerosol detection, it will also enable higher sensitivities. A typical chromatogram and conditions are presented.
