Packed colume
The separation column is the heart of the chromatograph. It provides versatility in the types of analyses that can be performed. This versatility, due to the wide choice of materials for the stationary and mobile phases, makes it possible to separate molecules that differ only slightly in their physical and chemical properties. Broadly speaking, the distribution of a solute between two phases results from the balance of forces between solute molecules and the molecules of each phase.
It reflects the relative attraction or repulsion that molecules or ions of the competing phases show for the solute and for themselves. These forces can be polar in nature, arising from permanent or induced dipole moments, or they can be due to dispersion forces. In ion-exchange chromatography, the forces on the solute molecules are substantially ionic in nature but include polar and nonpolar forces as well. The relative polarity of solvents is manifested in their dielectric constant.