Saturday, May 2, 2020

Principle and applications of paper chromatography

Paper chromatography is a separation technique in chemistry that is used to separate molecules or substances, particularly colored substances. It is mainly used as a teaching tool, replaced by other chromatography methods, for example, thin-layer chromatography (TLC). It is also used to testing the purity and identifying of molecules. The major advantage of paper chromatography is that it is relatively quick, simple, and requires a small amount of sample.
The principle of paper chromatography:
The basic principle involved in paper chromatography is partition chromatography in which the compounds are partitioned. The water that is held in the pores of the filter paper used is one phase and another is the mobile phase that passes over the stationary phase. Under the capillary action, the mobile phase is run over the stationary phase, the analytes are isolated due to differences in their affinity towards the stationary phase. The analytes with a low affinity toward the stationary phase are rapid travels than the analytes of higher affinity.
The principle may also be adsorption chromatography of solid and liquid phases, in which the stationary phase is the solid paper surface and the mobile phase is the solvent or mixture of solvents. However, the principle of partition chromatography is the most used in paper chromatography. Once the molecules get separated, the Rf value can be calculated, which is used to determine the characteristic of the molecules and to identify the compounds.
Various essential components involved in a paper chromatography process.
Specialized cellulose paper, chromatographic chamber, solvent, and detecting or visualizing agents, etc.
Major steps involved in the process of paper chromatography are.
1. Choose the appropriate type of development
2. Choose the appropriate filter paper
3. Sample Preparation
4. Sample spotting on the paper
5. Development of chromatogram
6. Drying of paper and detection of components

The applications of paper chromatography are as follows.
  • To analyze the processes of fermentation and ripening it can be used.
  • Forensic and pathology science are also used in this technique, mainly in DNA and RNA fingerprinting.
  • The presence of chemicals or alcohol in the blood can be determined by paper chromatography
  • It is one of the techniques used to isolate amino acids.
  • It is used to detect the presence of impurities beverages and foodstuffs.
  • This technique is mainly useful in separating colored pigments from a complex mixture.
  • Paper chromatography is also used by manufacturers of cosmetics.
  • The reaction mixture can be determined using paper chromatography.
Commonly asked questions on paper chromatography are as follows.  

What are the different types of paper chromatography?
Paper chromatography has 5 types such as ascending chromatography, descending chromatography, ascending-descending chromatography, radial or circular chromatography, and two-dimensional chromatography.

What is the basic principle of paper chromatography?

The basic principle of paper chromatography is partition chromatography.

What does a high RF value mean in paper chromatography?
A high Rf value in paper chromatography means that the component is very non-polar.

Why do amino acids travel different distances in chromatography?

Due to the variations in R groups of amino acids, the different amino acids travel at different rates on the paper.


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