Size+Exclusions+Chromatography+(SEC)

Chromatography is defined as a separation method in which the analyte is contained in a mobile phase and pumped through a stationary phase. Size exclusion chromatography (SEC) is a separation technique based on the molecular size of the components. Size exclusion chromatography is also knows as gel-filtration chromatography and uses porous particles to separate molecules of different sizes. Molecules that are smaller than the pore can enter the particles resulting in a longer path length and a longer elution time than the larger molecules (Tissue, 2003).The stationary phase consists of gel beads containing pores that span a relatively narrow size range. The pore size is determined by the extent of cross linking between the polymers of the gel material (Voet, Voet & Pratt, 2013).
 * Basic Description: **

The purpose of SEC is to separate biological molecules, and to determine molecular weights and molecular weight distributions of polymers (Tissue, 2003). It is also used for the fractionation of proteins and other water-soluble polymers.
 * Purpose of this Technique: **

**Origin and History:** Size exclusion chromatography was invented by Grant Henry Lathe and Colin R Ruthven while working at Queen Charlotte’s Hospital in London ("Size exclusion chromatography,”).

**Recent Research:** Size exclusion chromatography is being used for the purification of human immunoglobulin G (IgG) from a Chinese hamster ovary (CHO) cell supernatant. Partitioning of antibodies is known to be highly dependent on biomolecule properties and system composition, which can be analyzed by SEC (Azevedo, Rosa, Ferreira & Aires-Barros, 2008). Size exclusion chromatography was also used to analyze and purify specific plasmid isoforms. Using the SEC retention data, the plasmid partition coefficients were evaluated.it was found that he partition coefficient decreased with increasing plasmid size (Zydney & Latulippe, 2009). Lastly, SEC was used to determine the following dimensions of membrane proteins: the radius at the midpoint of the membrane, the average radius, the Stokes radius, and the excluded volume. The molecular mass of the protein was determined by two independent measurements that arise from the behavior of the free detergent micelle and protein–detergent micelle during size exclusion chromatography (Kunji, Harding, Butler & Akamine, 2008).


 * References **
 * 1) (n.d.). Size exculsion chromatography. Retrieved from []
 * 2) Azevedo, A. M., Rosa, P. A. J., Ferreira, I. F., & Aires-Barros, M. R. (2008). Integrated process for the purification of antibodies combining aqueous two-phase extraction, hydrophobic interaction chromatography and size-exclusion chromatography. //Journal of Chromatography A//, //1213//(2), 154-161.
 * 3) Kunji, E. R. S., Harding, M., Butler, J. G., & Akamine, P. (2008). Determination of the molecular mass and dimensions of membrane proteins by size exclusion chromatography. //Methods//, //46//, 62-72.
 * 4) Tissue, B. M. (2003, June). //The chemistry hypermedia project//. Retrieved from []
 * 5) Voet, D., Voet, J. G., & Pratt, C. W. (2013). //Fundamentals of biochemistry//. (4th ed., pp. 99-101). Hoboken, NJ: John Wiley & Sons, Inc.
 * 6) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Zydney, A. L., & Latulippe, D. R. (2009). Size exclusion chromatography of plasmid DNA isoforms. //Journal of Chromatography A//, //1216//, 6295-6302.