For sites describing separation of chemicals, their aggregates and particles on the basis of size, commonly known as filtration.
Size Exclusion generally refers to separations in which analytes are retained in a controlled manner, whilst larger species are removed from the matrix.
This also includes separation of macromolecules, by gel filtration, either in their biologically active state,
after being charged as with detergents such as SDS,
or after ionisation, such as matrix assisted laser desorption, for MALDI-TOF mass spectrometry.