Important definitions in chromatography

Affinity:

 natural attraction or force between things

Mobile Medium:

gas or liquid that carries the components (mobile phase)

Stationary Medium:

 the part of the apparatus that does not move with the sample (stationary phase)

Retention time:
It is the difference in time between the point of injection and appearance of peak maxima.

 Retention volume:
Retention volume is the volume of carrier gas required to elute 50% of the component from the column.
 Retention volume = Retention time × Flow Rate.

Resolution:
Resolution is a measure of the extent of separation of two  component.
 

Rf  value:
Is the ratio of distance travelled by the solute to the distance traveled by the solvent.
It range from 0 to 1.