How Does SEC Work?
Size exclusion chromatography (SEC) is based on the ability of sample components of different sizes to migrate in and out of pores on the stationary phase to different extents. Ideally, there is no intermolecular interaction between the sample and the stationary phase. Larger analytes are not able to travel as far into the pores as smaller analytes, so they spend less time in the pores and elute from the column earlier. Smaller analytes can more effectively enter the pores, so they spend more time there and elute from the column later.