Theory
Calculating the Rf value in chromatography
In chromatography, substances move across paper or a plate along with the solvent.
The Rf value compares how far the substance travelled with how far the solvent front travelled.
Measure both distances from the same starting line and use Rf = substance distance / solvent front distance.
- Read both distancesMeasure both distances from the same starting line.
- Divide the substance distance by the solvent front distanceThe Rf value is the distance of the substance divided by the distance of the solvent front.
Calculate the Rf value with a substance distance of 3,2 cm and a solvent front distance of 8 cm.
- Read both distancesSubstance distance = 3,2 cm and solvent front distance = 8 cm.
- Divide the substance distance by the solvent front distance3,2 ÷ 8 = 0,4.