- GPC (Gel Permeation Chromatography),
- GFC (Gel Filtration Chromatography) and
- SEC (Size Exclusion Chromatography)
are names used to describe the same liquid column chromatographic technique required to determine important properties of macromolecules, also known as polymers, biopolymers, polysaccharides or proteins. Independent of the abbreviation used, the separation mechanism behind these names is the same. SEC is the name that describes the chromatographic process best, as molecules are sorted by their size.
The size separation step occurs in a column filled with porous particles (stationary phase) and is an entropic driven process. First, the sample is dissolved in a solvent, which is also used as a mobile phase. The sample solution is injected onto the column. Here larger sizes are excluded from penetrating the pores in the stationary phase particles while smaller sizes can enter them and thus are retarded on their way through the column.
The analysis goals in modern SEC applications are very diverse and range from purification to quality control and determination of structure-property relationships where molar masses, composition, branching or end groups are determined. The wide applicability and the fact that SEC can be easily automated has made SEC one of the most important techniques for measuring properties of synthetic and natural macromolecules.