Britannica
Sources used in this answer
Why do polar stationary phases retain polar solutes more strongly?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
chromatography
Overview of the chemical technique of chromatography.
In chromatography, the principle that polar stationary phases retain polar solutes more strongly is rooted in the fundamental chemical rule that "like dissolves like".1
Retention occurs because solutes are attracted to the stationary phase through various intermolecular forces. When a stationary phase is polar, it exerts stronger attractive forces on polar solutesâwhich possess an asymmetrical distribution of electronsâcompared to nonpolar solutes. These forces include:2
- Orientation effects: The mutual attraction between polar molecules resulting from the alignment of dipoles.2
- Hydrogen bonding: Interactions between dipolar molecules that bear electron-pair-accepting hydrogen atoms.2
- Induction effects: The ability of polar molecules to induce charge asymmetry in other molecules.2
- Acid-base interactions: The affinity between Lewis acids and Lewis bases.2
Because polar solutes are more strongly attracted to the polar stationary phase through these interactions, they migrate more slowly through the system, while nonpolar solutes are passed more readily.21