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Parts of The Column and Its Procedure of Open Column Chromatography


This is a glass column with two open ends. Usually in small laboratories a burette is used instead of a glass column. The upper end should be wider than the bottom end. Also at the bottom there should be a stopcock to control the solvent flow. The bottom end is packed with glass wool or cotton wool. It is to prevent the occurring of any damages to the stopcock from the solvent flow and to support the stationary phase. A solid packing material is filled as the stationary phase. The solid material can vary depending on the mode of separation such as adsorption, partition etc.

The mode of separation of this technique is adsorption and the separation is based on the polarity of the substances. The stationary phase used in this is a finely divided polar material. It is finely divided in order to increase the surface area and it should be polar than the mobile phase that is used. Most common packing materials are silica gel (SiO2), Alumina (Al2O3) and also cellulose MgO and BaSO4 are also been used. The mobile phase is a solvent or a solvent mixture. Solid adsorbent should be in uniform size and should have a large surface area. Also the solvent (mobile phase) should be relatively less polar than the compounds to be separated.


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