Glossary Of HPLC-LC Separation Terms – W

The listing should be helpful to those just starting in HPLC but it also can serve as a refresher for long-time users in the field.


Wall effect: The consequence of a looser packing density near the walls of a rigid HPLC column. The mobile phase has a tendency to flow slightly faster near the wall because of the increased local permeability. The solute molecules near the wall are carried along faster than the average of the solute band, and, consequently, band spreading results and the column loses efficiency.

WCX: See weak cation exchanger.WAX: See weak anion exchanger.

w b See peak width.

Weak anion exchanger: Anion-exchange packing with weakly basic ionogenic groups such as amino diethylamino ethyl groups.

Weak cation exchanger: Cation-exchange packing with weakly acidic ionogenic groups such as carboxyl groups.

Weak solvent: In chromatography, refers to the mobile phase constituent that provides a low solvent strength that causes an analyte to elute more slowly from the column; in a water-acetonitrile binary solvent system for reversed-phase LC, water would be considered to be the weak solvent. In a normal phase chromatography binary solvent system of hexane-isopropanol, hexane would be the weaker solvent.

Wilke–Chang equation: A semi-empirical equation used to estimate diffusion coefficients in liquids as a function of solute molecular size and solvent viscosity.


Go up