In the world of analytical chemistry, few topics cause as much confusion as the difference between the terms GPC, SEC, and GFC. You’ve likely seen them used interchangeably, leading to the question: are they the same thing? The short answer is yes, but the full answer is more nuanced. Understanding the differences between GPC, SEC, and GFC is key to communicating effectively and choosing the right term for your work.
Gel Permeation Chromatography (GPC), Size Exclusion Chromatography (SEC), and Gel Filtration Chromatography (GFC) all refer to a powerful analytical technique used to separate the molecules of a polymer sample based on their size. This method is a type of liquid chromatography where the separation occurs in a column packed with porous beads (the stationary phase).
The fundamental principle is the same: larger molecules can only enter the largest pores and therefore travel through a more direct flow path, eluting first. Smaller molecules, in contrast, can enter a greater number of pores and follow a more tortuous internal pathway, increasing their residence time within the column and eluting later. By measuring the elution volume, we can determine the molar mass distribution of a material, a critical parameter for quality control and research.
To understand why three names exist for the same analytical process, we have to look at the scientific developments as they happened:
The principles of size exclusion chromatography were first demonstrated by British biochemists Gordon Lathe and Colin Ruthven in 1955[1]. Their initial work focused on starch gels for separating biomolecules in aqueous solvents. In their paper “The separation of substances and estimation of their relative molecular sizes by the use of colums of starch in water”, they described a molecular-sieve-based partition system.
2. Development of Gel Filtration (Porath & Flodin)A few years later, in 1959, a new term – Gel Filtration – was coined by Swedish biochemists Jerker Porath and Per Flodin[2]. Their work demonstrated size separation of peptides and oligosaccharides using a series of cross-linked dextran packings with different pore sizes.
3. Birth of Gel Permeation Chromatography (Moore)In 1964, J.C. Moore of the Dow Chemical Company successfully developed a method that allowed for the separation of synthetic polymers based on size using polystyrene resins as stationary phase, coining this new method Gel Permeation Chromatography[3].
Due to their scientific origins, Gel Filtration Chromatography stuck as the term employed when separating biopolymers in an aqueous mobile phase, while Gel Permeation Chromatography became the term used by the synthetic polymer industry.
Over the years, the name Size Exclusion Chromatography emerged as the more general and descriptive term for this type of separation technique. SEC implies that molecules are sorted by their size, independent of the solvent used, the stationary phase, or the polymer nature. Therefore, SEC encompasses both GPC and GFC.
Yes, scientifically speaking, SEC, GPC, and GFC describe the same technique – a separation based on molecular size.
The constituting parts – column, stationary phase, solvent, pump, and detector – are common in all three nomenclatures. And the physics of how they separate a sample based on the size of its molecules does not change.
So, while the technique is the same, the term you use can signal the type of material you are analyzing:
| Size Exclusion Chromatography (SEC) | Gel Permeation Chromatography (GPC) | Gel Filtration Chromatography (GFC) | |
|---|---|---|---|
| Core Principle | Separation by size (hydrodynamic volume) | Separation by size (hydrodynamic volume) | Separation by size (hydrodynamic volume) |
| Typical Material | General term used for all polymers | Synthetic Polymers | Biopolymers |
| Common Solvent | Aqueous or Organic | Organic | Aqueous |
Choosing the right term depends on your audience and your material.
Ultimately, the SEC-GPC-GFC difference is not about the technique, instead it lies purely in the terminology and historical context. SEC is the scientific umbrella term, while GFC is the preferred term in fields like biochemistry, and GPC is the specific application of SEC for synthetic polymers.
Whichever term you use, the most important thing is to be consistent within your own work.
References
Frequently Asked Questions
Yes, they all refer to the same separation mechanism: molecules are separated based on their hydrodynamic size using porous particles in a chromatography column.
There is no technical difference in the underlying technique.
SEC is the umbrella term, describing size-based separation in any solvent system.
GPC is a subset of SEC, used specifically for synthetic polymers analyzed in organic phase systems.
GFC is also a subset of SEC, used specifically for biopolymers analyzed in aqueous phase systems.
The terminology evolved independently in different scientific communities:
- GFC arose in biochemistry (1950s) using dextran gels and aqueous solvents.
- GPC emerged in polymer science (1960s) using polystyrene gels and organic solvents.
- SEC was later adopted as a universal, solvent-independent description of the technique.
These historical paths created multiple names for the same size-based mechanism.
Many scientists consider SEC the most precise term because it directly describes the mechanism (size exclusion) without implying a type of stationary phase (“gel”) or solvent.
But all three terms are correct when used in the proper context.
“Gel” is a historical reference to early stationary phases (dextran, agarose, or polystyrene gels).
Modern SEC/GPC/GFC columns use highly engineered porous particles, not literal gels, but the terminology persisted.
Use SEC, as it is universal, solvent-independent, and instantly communicates that the technique is based on size exclusion.
