What is size exclusion chromatography?

Size exclusion chromatography (SEC), also known as gel permeation chromatography (GPC) or gel filtration chromatography, is a chromatographic method in which molecules in solution are separated by their size, and in some cases molecular weight. It is commonly used to separate biological molecules such as proteins and polymers. Smaller molecules can enter the pores of the stationary phase, retarding their elution, while larger molecules are excluded and elute earlier.