What does Rf, (or relative to front) mean?


What does Rf, (or relative to front) mean?

Relative to Front

Relative to front (Rf) is a measure of how far the mobile phase in a thin-layer chromatograph will move up the stationary phase. Generally, in TLC, the less polar molecule will move further on the plate as usually plates with a polar coating are used.

Answer and Explanation: 1

Rf can help determine the polarity of a certain molecule, or, if the relative polarities of certain components of a mixture are known, it can help determine the identity of certain spots on a chromatograph. The Rf is defined as the spot's distance from the baseline divided by the distance from the baseline to the solvent front. Depending on the solvent and coating of the plate, the Rf will vary between different solutions, as particles which are heavier or more/less polar will not move as far on the plate. The person performing the TLC can use the Rf to reveal different things about the solutions dependent on the aforementioned variables.

Learn more about this topic:

Retention Factor in Chromatography: Definition & Formula


Chapter 1 / Lesson 9

Understand what the retention factor in chromatography is by learning its definition. Learn how to calculate retention factor using the retention factor equation.

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