An alternative technique to reversed-phase HPLC for the separation of highly polar analytes that may be only slightly retained by reversed-phase chromatography, HILIC requires a high percentage of a nonpolar mobile phase and a polar stationary phase, similar to the requirements in normal phase chromatography. However, unlike normal-phase chromatography, which uses nonpolar solvents such as hexane and methylene chloride and tries to exclude water from the mobile phase, HILIC requires some water in the mobile phase to maintain a stagnant enriched water layer on the surface into which analytes may selectively partition. In addition, water-miscible organic solvents are used instead of the water-immiscible solvents used in normal-phase chromatography. With HILIC, sorbents such as bare silica, bonded diol, and polyhdroxyethylaspartamide are used. Polar analytes are well retained and are eluted in order of increasing hydrophilicity, just the inverse of reversed-phase LC.