Liquid chromatography of macromolecules at the point of exclusion–adsorption transition |
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Authors: | D Berek |
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Affiliation: | (1) Polymer Institute of the Slovak Academy of Sciences, 842 36 Bratislava, Slovakia e-mail: upolber @savba.sk, SK |
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Abstract: | Liquid chromatography of macromolecules at the point of exclusion–adsorption transition (LC PEAT) is based on a controlled
balance between entropic (exclusion) and enthalpic (adsorption) effects within LC system that results in the loss of separation
according to the molar mass. Consequently, polymer species exhibiting the same adsorptivity but different sizes are eluted
in one single retention volume that roughly corresponds to the total volume of liquid within column. At the same time, other
kinds of polymer chains with different adsorptivities are eluted according to either exclusion or adsorption mechanism. This
may allow discrimination and independent characterization of chemically different species such as functionalized macromolecules,
block- and graft- copolymers and polymer blends. Differences in the physical structure of macromolecules, for example in their
stereoregularity represent an alternative separation parameter.
Four approaches to the exclusion–adsorption transition in liquid chromatography of macromolecules were so far proposed, viz.
liquid chromatography at the critical adsorption point (LC CAP), liquid chromatography at the theta exclusion-adsorption conditions
(LC TEA), liquid chromatography under limiting conditions of adsorption (LC LCA) and liquid chromatography under limiting
conditions of desorption (LC LCD).
The principles of LC CAP, LC TEA, LC LCA and LC LCD and their applicability are elucidated and the advantages and problems
of particular methods are discussed in the present review.
Received: 9 October 2000 / Reviewed and accepted: 10 October 2000 |
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Keywords: | Liquid chromatography Exclusion– adsorption transition |
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