Enter the distance travelled by the compound and the distance travelled by the solvent into the calculator to determine the Retention Factor (Rf). The Retention Factor is a dimensionless number that represents how far a compound travels in a chromatography experiment relative to the solvent front.
Retention Factor (Rf) Formula
The following formula is used to calculate the Retention Factor (Rf):
Rf = Dc / Ds
Variables:
- Rf is the Retention Factor
- Dc is the distance travelled by the compound (cm)
- Ds is the distance travelled by the solvent (cm)
To calculate the Retention Factor, divide the distance travelled by the compound by the distance travelled by the solvent.
What is a Retention Factor?
The Retention Factor, or Rf, is a measure used in thin-layer chromatography (TLC) to evaluate the progress of a chromatographic separation. It is a ratio of the distance a solute travels on the chromatogram relative to the distance the solvent front travels from the baseline. A lower Rf value indicates that the compound is less mobile in the solvent, while a higher Rf value suggests greater mobility. The Rf value can be used to identify compounds by comparing it to known standards.
How to Calculate Retention Factor?
The following steps outline how to calculate the Retention Factor (Rf).
- First, measure the distance travelled by the compound (Dc) on the chromatogram from the baseline to the center of the spot in centimeters.
- Next, measure the distance travelled by the solvent (Ds) from the baseline to the solvent front in centimeters.
- Use the formula Rf = Dc / Ds to calculate the Retention Factor.
- Finally, enter the measured values into the calculator above to find the Rf value.
Example Problem :
Use the following variables as an example problem to test your knowledge.
Distance travelled by the compound (Dc) = 2.5 cm
Distance travelled by the solvent (Ds) = 5.0 cm
