CHROMATOGRAPHY is a very important technique widely used in analytical chemistry, biochemical and biotechnology industries.
The term CHROMO means color and GRAPHY means script. Through chromatography we can find various components in a mixture in a color picture form.
In chromatography technique the components of a mixture are separated based on the differences in the rates at which the components carried through a fixed or stationary phase by a gaseous or liquid mobile phase.


Chromatography was discovered by Poland botanist M.S. Tswette in 1906.Tswette-chromatography He used chromatography technique for separation of plant pigments. Later many advances takes place in chromatography various types of chromatography techniques are evolved.


For example when "Spinach" leaves are used for this type of separation using A1203 , CaC03 and sugar as adsorbing substance different components are resolved into different colored zone as shown in the side diagram.
The banded column of adsorbent is termed as chromatogram. The organic liquid (petroleum + Base) is the mobile phase and adsorbent material is the stationary phase. The above operation of separating the colored zones is called "development of chromatogram. chromatography-paper
The most startling results have been obtained in the field of plant pigments. Chromatography has also many applications in the laboratories. The separating substance need not be highly colored to give a visible adsorption band. chromatography-chrmatogram
Certain colorless substances exhibit a bright fluorescence in U.V.light Source of U.V. radiations is quarts mercury vapor lamp.


Methods have been developed for processing colorless and non-fluorescent compounds such as
(1) Conversion of the compounds into colored derivative
(2) Use of indicator or making substance
(3) Substances to be separated give a color test with suitable reagent.
Chromatography is plays a very important role in biotechnology, biochemistry, analytical chemistry, and pharmacy industry the main use of chromatography is
· Separating a mixture into their components with precision.
· Purification of substances accurately.
· Determination of homogeneity of chemical substances.
· Comparison of substances of identical properties.
· increasing the concentration of dilute solutions
· Quantitative separation of one or more constituents from a complex mixture.
· Identification and control of technical products.