HILIC is a variation of normal phase chromatography. The major differences between HILIC and NP are the composite of the mobile phase and the mechanism of separation. Common NP chromatography uses 100 % organic mobile phases while HILIC uses organic mobile phases that are water miscible. The HILIC separation mechanism is caused by an aqueous layer built on the stationary phase and partitioning of the analytes between the very polar stationary phase and the less polar mobile phase.