Size Exclusion Chromatography
Size Exclusion Chromatography (SEC) separates molecules based on their size, or more precisely, their hydrodynamic volume. It is based on the discrimination of individual sample components by the pores of the packing material. Large sample molecules cannot or can only partially penetrate the pores and elute from the column first, whereas smaller molecules can access all or a larger number of pores and elute later. SEC is the only mode of chromatography that does not involve interaction with a stationary phase by means of adsorption or partitioning of the solutes.
The terms SEC, GFC (gel filtration chromatography) and GPC (gel permeation chromatography) all refer to the same chromatographic technique. In GFC an aqueous mobile phase is used, while an organic mobile phase is employed in GPC. The general term SEC covers both uses.
SEC is the dominant mode of separation for natural and synthetic polymers:
GFC is the term used for the size-based separation of water-soluble polymers, for example biopolymers or natural polymers.
GPC is the term used for the size-based separation of polymers soluble in organic solvents.
TSKgel SEC Columns
Size exclusion chromatography columns are traditionally packed with porous polystyrene divinylbenzene (PS-DVB) or silica particles. PS-DVB columns are commonly used for the analysis of synthetic polymers in organic solvents, while silica-based columns are used for the separation of biopolymers.