Basic equation for size exclusion chromatography:

The basic equation for size exclusion chromatography is

V_R = V₀ + KV_L

where, V_R is retention volume, V₀ is the interstitial volume, K is some form of distribution coefficient and V_L is the volume of water within the gel particles.

Normally, the K value greater than 1 is not encountered. If it is encountered, it implies the occurrence of phenomena like adsorption, hydrogen bonding and ion exchange between the gel matrix and the solute.