What is Rf value in thin layer chromatography?
What is Rf value in thin layer chromatography?
In thin-layer chromatography, the retention factor (Rf) is used to compare and help identify compounds. The Rf value of a compound is equal to the distance traveled by the compound divided by the distance traveled by the solvent front (both measured from the origin).
What is the Rf value in paper chromatography?
The Rf value is defined as the ratio of the distance moved by the solute (i.e. the dye or pigment under test) and the distance moved by the the solvent (known as the Solvent front) along the paper, where both distances are measured from the common Origin or Application Baseline, that is the point where the sample is …
Can a substance have 2 Rf values?
The larger an Rf of a compound, the larger the distance it travels on the TLC plate. If two substances have the same Rf value, they are likely (but not necessarily) the same compound. If they have different Rf values, they are definitely different compounds.
Can an Rf value be greater than 1?
Long Answer: Rf is the “Retardation Factor”, which is the ratio of the distance traveled by a compound in a mobile phase compared with the distance traveled by the front of the mobile phase itself. It is always greater than or equal to zero, and less than or equal to 1.
What are the 2 phases of chromatography?
Chromatography is a physico-chemical method for separation of compound mixtures, based on the distribution of components between two phases, one of which is stationary (sorbent), and the other, mobile, flowing through a layer of the stationary phase.
Can an RF value be greater than 1?
What is the maximum RF value possible?
An RF value will always be in the range 0 to 1; if the substance moves, it can only move in the direction of the solvent flow, and cannot move faster than the solvent. For example, if particular substance in an unknown mixture travels 2.5 cm and the solvent front travels 5.0 cm, the retardation factor would be 0.50.
Why must RF value be less than 1?
By definition, Rf values are always less than 1. An Rf value of 1 or too close to it means that the spot and the solvent front travel close together and is therefore unreliable. This happens when the eluting solvent is too polar for the sample.
Can Rf value be greater than 1?
