In chromatography, the retardation factor (R) is the fraction of an analyte in the mobile phase of a chromatographic system.
[1] In planar chromatography in particular, the retardation factor RF is defined as the ratio of the distance traveled by the center of a spot to the distance traveled by the solvent front.
In chromatography, the retardation factor, R, is the fraction of the sample in the mobile phase at equilibrium, defined as:[1] The retardation factor, RF, is commonly used in paper chromatography and thin layer chromatography (TLC) for analyzing and comparing different substances.
One can choose a mobile phase with different characteristics (particularly polarity) in order to control how far the substance being investigated migrates.
An RF value is characteristic for any given compound (provided that the same stationary and mobile phases are used).