Chromatography Theory

Retention Theory:

The retention is a measure of the speed at which a substance moves in a chromatographic system. In interrupted development systems like the retention is measured as the retention factor R_f, the run length of the compound divided by the run length of the solvent front:

Rf Value:

The distance moved by a particular spot from the origin line is measured and related to the position of the solvent front. The ratio of those distances is called the Rf value. This value is used to identify the substance.
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Rf value