What is the difference between HILIC columns and common HPLC columns?

What is the HILIC column?

HILIC is short for Hydrophilic interaction liquid chromatography, sometimes referred to as "aqueous normal phase chromatography". HILIC column is similar to the normal phase HPLC column. But its water resistance is better.

Common HILIC columns include silica columns, NH2 columns, diol columns, amide columns. The stationary phase of pure silica columns is not easily lost. Amino columns, commonly used language carbohydrate (sugar) separation. Diol-based columns have good hydrophilicity and can provide different selectivity.

What is the difference between HILIC columns and common HPLC columns?

Compared with normal phase columns, HILIC columns can be used in aqueous/organic mobile phases. HILIC requires higher water-resistance of the stationary phase. Otherwise, problems such as high baseline noise and short column life will occur due to hydrolysis of the stationary phase.

In short, normal phase columns may not be used in HILIC chromatography. But HILIC columns can be used in normal phase chromatography.

The requests for the mobile phase with HILIC columns?

In most HILIC testings, the mobile phase used is a mixture containing a small amount of water/buffer with the organic phase (typically acetonitrile). The proportion of water is ranged from 3% to 40%.

It is generally believed that the water in the mobile phase of HILIC chromatography will be adsorbed to the surface of the polar stationary phase to form a water film. The analytes will be partitioned between the water film and the mobile phase. Together with the hydrogen bonding force between the polar functional groups and the stationary phase, and the electrostatic force between the ionic functional groups, the HILIC column can achieve the retention of the analytes. The role of aqueous membranes is very important, and the mobile phase contains at least 3% water. When the percentage of water is greater than 40%, the retention is generally very weak (k ≈ 0).