Question

Chromatography has many applications. Research one application of chromatography and explain how it is used and what characteristic is used for the separation of the analyte

Answer 1

Chromatography is an analytical procedure used to separate mixture of chemicals present in the mobile phase by passing it through a stationary phase. chemicals present in the mixture travel at different speed along the stationary phase, and thus, they will get separated. Based on mechanism of separation, there are several types of chromatography, some of the important are

1. Thin layer chromatography (TLC).

2. Gas chromatography (GS).

3. High performance liquid chromatography (HPLC).

4. Paper chromatograpy.

Separaion of amino acids in a mixture is one of the important application of thin layer chromatograpy. Here I am explaining that.

Separation of amino acids by TLC: In TLC, stationary phase is any inert material like silica gel, aumina or cellulose. Stationary phase is prepared like a slurry and is poured uniformely as a thin layer over flat surface (preferably glass slides). Now the mixture to be separated is placed as a spot at one end of the plate and allow to dry. Place the plate in a solvent system (sample spot should not be immersed in solvent). The amino acids present in the mixture have different solubilities in the mobile phase. As the mobile phase moves, the amino acids also move along the plate (according to their partition equilibrium), we can identify this as a coloured spot.

Rf value = Distance travelled by the substance from origin/Distance travelled by the solvent from origin.

Rf value is characteristic of amino acid, thus we can separate and identify amino acids by TLC.