Chromatography is a technique used for the separation of a mixture by passing it through a medium in which the components of the mixture move at different rates.
The wordchromatographycomes from the Greek wordschroma,这意味着color, andgraphos,这意味着to draw. This name was chosen by the Russian botanist, Mikhail Tswett, in 1906. He separated different pigments from a plant extract by loading a sample mixture onto a calcium carbonate column.
Figure 1.Tswett's method of separating a mixture of pigments from a plant extract.
By passing a solvent (mobile phase) through the column (stationary phase) the different components of the sample moved at different rates down the column due to their chemical and physical properties. As a result, Tswett separated and collected each of the three dye molecules that make up chlorophyll, and developed a now widely used and versatile technique. Today, chromatography is used for the separation, purification, and identification of compounds.