Purification+through+Column+Chromatography

__**Purification through Column Chromatography **__


 * Basic Description: **

The technique of column chromatography is done by passing a solution through a column matrix to then extract out the desired molecules. More specifically, a sample is applied to the top of a cylindrical glass or plastic column. This is often filled with a permeable or porous solid matrix. The bottom of the column is filled, usually with cotton to prevent the stationary phase from being washed out. The column is then loaded with silica gel or alumina. A large solvent is then slowly pumped through the column and collected in separate tubes as it emerges from the bottom. The components are then fractioned into different tubes (due to the different rates as they pass through the column) from the sample [2]. The proteins elute from the column at different speeds depending on their size and how they interact with the matrix. Different components elute at different times and therefore can be collected individually and analyzed [2]. Proteins are most often isolated and extracted using this method, but other molecules can be extracted by size, charge, hydrophobicity, isoelectric point, and so on.


 * Purpose of Technique: **

The purpose of an extraction is so one can separate and purify the substance they are observing. Through this purification, they can then understand how the components within the cell function. In doing this, it provides one with the information on cellular functioning within a tissue. From this biologists have developed ways to analyze and purify cells according to type.


 * Origin and History: **

The general technique of chromatography was first demonstrated by Russian scientist Mikhail Tsvet in 1906. He continued to work with chromatography in the first decade of the 20th century, primarily for the separation of plant pigments [1]. More modern types of chromatography, such as column chromatography, were developed during the early to mid 1900s. This well known technique is still found useful today in many purification processes.


 * Recent Research: **

There are many other types of chromatography; however column chromatography is the cheapest because most of the supplies are disposable, which eliminates most cross contamination. The downside is that column chromatography only produces small quantities of product and cannot be used for large scale projects.


 * References: **

[1] Abraham MH (2004) 100 years of chromatography—or is it 171? Journal of Chromatography A 1061: 113–114 [2] Alberts B, Johnson A, Lewis J, Raff M, Roberts K, Walter P (2008) Manipulating Proteins, DNA, and RNA. Molecular Biology of the Cell, Ed 5. Garland Science, New York, pp 500-578