Question

What do you understand by chromatography and explain the different types of chromatography

Answer 1

Chromatography is a separation process of components of molecular mixtures. the separation depends upon the powers of component's distribution between two phases,namely stationary phase and the mobile phase. The stationary phase can be a solid or liquid; while the mobile phase is a liquid or gas. The mobile phase is a substance which moves in a definite direction. Whereas the stationary phase is the substance which is fixed in place for the chromatographic procedure.

The main types of chromatography include thin layer chromatography, paper chromatography,  gas chromatography and high-performance liquid chromatography.

Thin layer cgromatography :It is a chromatography technique in which the adsorbent layer is obtained on glass plate and elution is carried out as in the case of paper chromatography. It is separated in non-volatile mixtures.

paper chromatography : It is a technique where separation of a mixture of substances is mainely done by the flow of solvents on a specially designed chromatographic filter paper. The stationary phase is the water present in the cellulose of the filter paper and the mobile phase is an organic solvent which is immiscible with the stationary phase.

Gas chromatography : This is the latest technique for separation and identification of components of a mixture. In this technique the mobile phase is a gas like nitrogen,helium,argon etc.

High-performance liquid chromatography is a form of column chromatography and is a separation technique. a solvent (known as the mobile phase) are moved down the packed tube with a liquid through the column by high pressure delivered by a pump.