What is chromatography?

paper chromatography is made of two words “chroma” meaning “color” and “graphein” meaning “to write”. So chromatography means “color writing.” Chromatography is used to separate closely related chemical substances and it is based on difference in the migration velocity of the substances between a stationary phase and a mobile phase.

Thin Layer Chromatography

Chromatography one of the modern separation technique was first discovered by a Russian scientist Tswett. In this technique, separation of a mixture of substances is brought about by differential movement of individual components through a porous medium under the influence of a solvent. Since the discovery of this technique, it has undergone many changes and is now a very sophisticated technique.

The principle of this process depends upon “the different components of mixture are absorbed to different extends ad move down the column at different rates.” Selective adsorption of various components of a mixture between two phase one fixed phase and the other moving phase. The mixture to be separated is taken in the moving phase and passed over the fixed phase. Different components are adsorbed to different extents by the fixed phase. This results in separation of the mixture.

The various techniques of chromatography are paper chromatography, gas chromatography, column chromatography, thin layer chromatography, adsorption chromatography and gas liquid partition chromatography. Chromatography is used to separate amino acid in patients with inborn errors of metabolism, identification of reducing sugars in serum, separation of drug metabolites and for detection of poisons.