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a gellike material with pore sizes of such ranges as to exclude molecules above certain sizes; used in fractionating or purifying macromolecules.
1 a crystalline chemical separation device with molecular size pores that adsorbs small but not large molecules.
2 a cross-linked polymer that forms a porous sieve used as a supporting medium for chromatographic separation of mixtures of solutes.
molecular sieveA material (e.g., oxides: silicate, aluminate, zeolite crystals with pores) which is capable of separating molecules based on size.
A type of sieve in which the molecular material present in the gel or crystal will adsorb molecules of a certain kind and let others pass.
See also: sieve