Size-exclusion chromatography
Size-exclusion chromatography, also known as molecular sieve chromatography, is a chromatographic method in which molecules in solution are separated by their size, and in some cases molecular weight. It is usually applied to large molecules or macromolecular complexes such as proteins and industrial polymers. Typically, when an aqueous solution is used to transport the sample through the column, the technique is known as gel-filtration chromatography, versus the name gel permeation chromatography, which is used when an organic solvent is used as a mobile phase. The chromatography column is packed with fine, porous beads which are commonly composed of dextran, agarose, or polyacrylamide polymers. The pore sizes of these beads are used to estimate the dimensions of macromolecules. SEC is a widely used polymer characterization method because of its ability to provide good molar mass distribution (Mw) results for polymers.
Equipment for running size-exclusion chromatography. The buffer is pumped through the column (right) by a computer-controlled device. | |
| Acronym | SEC |
|---|---|
| Classification | Chromatography |
| Analytes | macromolecules synthetic polymers biomolecules |
| Manufacturers | Cytiva, Bio-Rad, Bio-Works, emp Biotech, Knauer, Phenomenex. |
| Other techniques | |
| Related | High-performance liquid chromatography Aqueous normal-phase chromatography Ion exchange chromatography Micellar liquid chromatography |
Size exclusion chromatography (SEC) is fundamentally different from all other chromatographic techniques in that separation is based on a simple procedure of classifying molecule sizes rather than any type of interaction.