Roughly speaking, compounds with low boiling points tend to elute at short retention times. The distribution coefficient determines the order of elution from column. When you put liquid sample in a vial, the analyte evaporates from liquid phase (solvent) into gas phase, some of it returning to liquid phase. After a while, equilibrium will be achieved. Under this condition, the ratio K=CL/CG is constant without relation to analyte concentration. This ratio is called distribution coefficient. K depends on temperature. This notion can also be applied to column separation. There is a liquid phase (stationary phase) layer inside a column. Carrier gas corresponds to gas phase. A compound with larger K remains in the liquid phase for longer.

Distribution Coefficient