Retention Factor
The ratio of the distance travelled by a component to the distance travelled by the solvent front.
Formula / equation
Rf = d_spot / d_solvent
Unit
Dimensionless
In depth
Always between zero and one, the retention factor is characteristic of a compound in a given solvent system and is used to identify substances by comparison with standards run alongside. It is reproducible only if temperature, plate and solvent are all kept constant.
Examples in the real world
A pigment travelling 3.6 cm while the solvent front travels 8.0 cm gives Rf = 0.45.