Chromatography is a technique used to separate mixtures into individual components. In 1906, Mikhail Tswett used calcium carbonate (chalk) to separate plant pigments by passing them through a chalk-filled glass tube with petroleum ether, resulting in distinct colored zones. This technique, known as column chromatography, can be performed in classrooms using chalk to separate mixtures based on how strongly components adsorb to the chalk and dissolve in the solvent.
Chromatography is a technique used to separate mixtures into individual components. In 1906, Mikhail Tswett used calcium carbonate (chalk) to separate plant pigments by passing them through a chalk-filled glass tube with petroleum ether, resulting in distinct colored zones. This technique, known as column chromatography, can be performed in classrooms using chalk to separate mixtures based on how strongly components adsorb to the chalk and dissolve in the solvent.
Chromatography is a technique used to separate mixtures into individual components. In 1906, Mikhail Tswett used calcium carbonate (chalk) to separate plant pigments by passing them through a chalk-filled glass tube with petroleum ether, resulting in distinct colored zones. This technique, known as column chromatography, can be performed in classrooms using chalk to separate mixtures based on how strongly components adsorb to the chalk and dissolve in the solvent.
Chromatography is a technique used to separate mixtures into individual components. In 1906, Mikhail Tswett used calcium carbonate (chalk) to separate plant pigments by passing them through a chalk-filled glass tube with petroleum ether, resulting in distinct colored zones. This technique, known as column chromatography, can be performed in classrooms using chalk to separate mixtures based on how strongly components adsorb to the chalk and dissolve in the solvent.
Chromatography is a technique used to separate components of a mixture.
In 1906, Mikhail Tswett, a Russian botanist, published a paper in which he described the separation of pigments, extracted from green leaves, by washing the mixture with petroleum ether (similar to lighter fluid) through a glass tube packed with powdered calcium carbonate (chalk). As the mixture of pigments passed down the CaCO3-filled tube, they separated into distinctly colored zones. Tswett gave the name chromatography (the graphing of colors) to this separation technique. The method that Tswett used is known today as column chromatography. The method of column chromatography can be carried out in the classroom using calcium carbonate in the form of sticks of chalk. A mixture containing two or more components is deposited on a stick of chalk, a solid adsorbing substance. The components are adsorbed (i.e., held on the surface of the solid substance) to varying degrees which depend on the nature of the component, the nature of the adsorbent, and the temperature. Then the wash solvent (liquid) is added to the adsorbent and allowed to flow through it by capillary effect. As the solvent passes the deposited mixture, the components tend to be dissolved to varying extents and are swept along the solid adsorbent. The rate at which a component will move along the solid depends on its relative tendency to be dissolved in the solvent and its tendency to be adsorbed on the solid. The net effect is that, as the solvent passes slowly through the solid adsorbent, the components of the mixture -separate from each other and move along with the solvent forming rather diffuse zones or spots. With the proper choice of solvent and adsorbent, it is possible to resolve many complex mixtures into their components.