Component separation within the column:

The procedure of separation could be considered as a series of partitions whereas the vaporized solutes from the injection port go into solution along with the liquid stationary phase and are then revaporized. The affinity of the liquid phase for sample elements determines the length of time for that every individual component will remain in solution. After a number of partitions, several solutes will separate within discrete bands and travel at different velocities by the column. The most volatile solute commonly passes by the column first and the least volatile or highest boiling solute emerges last. Figure demonstrates these stages of separation.

Figure:  Component separation within the column