high performance liquid chromatography, broad peaks

Factors affecting Rf value in TLC chromatography

During the thin layer chromatography, the retention factor of a chemical is the calculation of how distant the plate is taken in response to the movement of the solvent. Because the movement of chemical relies on how far the solvent travel is, we determine the retention factor values relative to the degree of solvent travels. The Rf for a particular chemical is the vertical distance traveled by a chemical from the place where it was originally spotted on the TLC plate, divided by the length traveled.
Retention factor or RF value is the difference in the movement rate of analytes in chromatography is due to various factors, some of them are mentioned here.

Thin Layer Chromatography Plate (TLC Plate):
TLC the plate can affect the Rf value of the component mixtures, it can be layered with different kinds of absorbent solids; Most often silica or alumina is used. Because the Rf value depends on the relative affinity of analytes for the absorbent, modifying the absorbent can change the retention factor significantly. Also, the thickness of the absorbents layer and uniformity may vary from plate to plate. These factors also cause to change retention factor values for components.

The polarity of the mobile phase:
Solvent polarity is related to Rf values in various solvents in the linear form of various nitro compounds. The differences in the solvent polarity can be affecting the Rf value.

Solvent impact on retention factors:
Since the solvent carries the analyte up the TLC plate, the solvent used also will affect the value of the component retention factor. A solvent which has a strong interaction for a specific analyte will more easily remove and carry that component forward in a certain period. The solvent mixture also has effects on the Rf value which is depending on the proportion of each solvent.

There may be slight changes in the temperature of the solvent and the plate can affect Rf value in chromatography, although the working temperature needs to monitor.

The technique of sample applying:
The technique of sample applying can also change the retention factor, the more amount of the sample may result in a large and diffuse band of component moving up the plate, makes it obscure to calculate the distance correctly. In some cases, several other factors can affect the retention factor in chromatography.


Go up