Size exclusion chromatography does not require pores
| Autor: | Werner E. G. Müller, Doina Hritcu, Bradley M. Steels, Charles A. Haynes, Donald E. Brooks |
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| Jazyk: | angličtina |
| Rok vydání: | 2000 |
| Předmět: |
chemistry.chemical_classification
Quantitative Biology::Biomolecules Chromatography Multidisciplinary Chemistry Polymers Size-exclusion chromatography Polymer Entropy of mixing Microspheres Partition coefficient Condensed Matter::Soft Condensed Matter Mean field theory Chemical physics Physical Sciences Partition (number theory) Particle size Particle Size Porosity |
| Popis: | Separation of macromolecules on the basis of their molecular weight by size exclusion chromatography has long been considered to be caused by the geometry-dependent partition of macromolecules between a continuous phase and the porous interior of a gel or cross-linked bead. The volume of a pore accessible to a solute is limited by its relative dimensions, so larger molecules will have access to a smaller volume and will remain in a bead for a shorter time than smaller solutes. Our recent alternate picture proposes that the partition coefficient can be calculated from a thermodynamic model for the free energy of mixing of the solute with the gel phase. Size-dependent exclusion caused by the unfavorable entropy of mixing associated with the partition is predicted; the magnitude of the effect is modified by enthalpic interactions between the solute and the gel phase. This concept is extended here to describe the partition of macromolecules into a layer of terminally attached polymer chains grafted onto a solid bead. Both simple mean field and self-consistent field theory calculations predict size-dependent entropic exclusion. Experimental results obtained with neutral polymer chains grafted onto solid polystyrene latex beads confirm the predictions. |
| Databáze: | OpenAIRE |
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