Friday, October 19, 2018

What is the principle of paper chromatography

The principle of paper chromatography involves "partition" in which compounds are distributed or partitioned between liquid phases.

The paper chromatography technique is parallel to the thin-layer chromatography. Paper chromatography has to be a very successful technique of separation, especially in the analysis of lipid samples and chemical compounds. In paper chromatography, a special type of chromatography paper or a piece of filter paper used as a stationary phase, which is made up with cellulose, sample mixture applied in this paper and paper edge is immersed in a solvent and by capillary action, solvents move up hence the separation of analytes happens.
The principle of paper chromatography involved is the partition in which the components are partitioned or distributed among the liquid phases. The two phases contain water in the pores of the paper and the other phase is a solvent system that travels through the paper. The molecules are separated into the mixture due to the differences in their respective affinity to water and mobile phase throughout the moving of the mobile phase. It also as adsorption chromatography among liquid and solid phases, in which the stationary phase is the solid surface and the mobile phase is the liquid. Although the most commonly used paper chromatography works on the principle of partition chromatography.
There are four different types of paper chromatography such as.
Ascending chromatography: in which the solvent flows by capillary action.
Descending chromatography: in which the mobile phase travels by gravitational force.
Ascending-descending chromatography: in which the solvent moves both upward and downward of the stationary phase,
Horizontal or circular chromatography: in which the sample is applied in the center of a round paper.
Two-dimensional chromatography: this applies to components that have the same Rf values.


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