Column Chromatography - Learning about how a column is constructed (Meritnation.com) скачать в хорошем качестве

Column Chromatography - Learning about how a column is constructed (Meritnation.com)

Visit http://www.meritnation.com for more videos for your class! This video deals with the column chromatography. But before you see the animation starts we would like to tell you what chromatography is? Well, chromatography is a set of techniques used for the separation of mixtures. Chromatography deals with the interactions between two different phases, the 'mobile phase' and the 'stationary phase'. The separation is based on the speed at which the various components of the mixture move through the stationary phase. Column chromatography is a type of cinematographic technique, wherein the stationary phase is present inside a column and the mobile phase containing the mixture to be separated is introduced into the column. In this video, we will be learning about how a column is constructed and how separation of the mixture is achieved. The column for chromatographic separation is constructed by first placing cotton at the bottom of a clean, dry column. On this, a thin layer of acid washed sand is placed to support the column. The stationary phase used in a column can be alumina, silica gel or cellulose. This stationary phase is mixed with a non-polar solvent such as hexane and is placed on top of the sand layer. The stationary phase is then topped again with a layer of acid washed sand. The mixture to be separated is then mixed with a highly polar solvent such as alcohol and is poured over the column. The individual components of the mixture are retained by the stationary phase differently and separate from each other while they are running at different speeds through the column.