Size Exclusion Chromatography
Definition and meaning of Size Exclusion Chromatography in chemistry.
Size exclusion chromatography is a highly versatile chromatographic method in which complex molecules in a liquid solution are separated strictly by their physical size, and in some cases molecular weight, rather than their chemical properties. It is predominantly applied to fractionate large molecules or macromolecular complexes.
In more detail
The stationary phase in the chromatography column consists of microscopic, porous polymer beads. Smaller molecules can easily enter the tiny pores within the beads, taking a longer, more winding and tortuous path through the column, which significantly delays their eventual elution. In contrast, larger molecules cannot physically enter the pores and are completely excluded, causing them to travel directly through the interstitial spaces faster and elute first from the column. This gentle technique is widely used in analytical biochemistry to purify folded proteins, remove small salt molecules, and accurately determine polymer molecular weight distributions.
Key facts
| Field | Analytical Chemistry |
|---|---|
| Separation basis | Molecular size or hydrodynamic volume |
| Elution order | Large molecules elute first |
Separating a large target protein from much smaller peptide fragments and buffer salts using a glass column densely packed with porous agarose gel beads.
Frequently asked questions
Does size exclusion chromatography denature fragile proteins?
No, it is explicitly a non-denaturing technique because it relies strictly on physical size sieving rather than harsh chemical interactions or binding affinities.