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Theoretical evaluation of K p in size‐exclusion chromatography from a thermodynamic viewpoint
Author(s) -
Gómez Clara M.,
García Rosa,
Figueruelo Juan E.,
Campos Agustín
Publication year - 2000
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20001101)201:17<2354::aid-macp2354>3.0.co;2-8
Subject(s) - ternary operation , size exclusion chromatography , chemistry , polymer , flory–huggins solution theory , ternary numeral system , thermodynamics , solvent , chromatography , phase (matter) , organic chemistry , physics , enzyme , computer science , programming language
The Flory‐Huggins formalism developed for a ternary solvent(1)‐polymer(2)‐polymer(3) system has been used to evaluate the binary and ternary interaction functions. The raw data are the two‐phase equilibrium compositions of the three components determined by liquid chromatography. These interaction functions have been used to evaluate theoretically the distribution coefficient of solute‐gel interactions in size exclusion chromatography (SEC), K p . For a system solvent(1)‐polymer(2)‐gel matrix(3), a new expression for K p has been obtained from a thermodynamic point of view. The proposed equation is a function of the fraction of gel matrix in the ternary phase, of the molar volumes of solvent and polymer and of the binary and ternary interaction functions. For the systems studied, values of K p higher and lower than unity have been obtained at different hydrodynamic volumes which evidences the existence of secondary mechanisms. These calculations lead to a better understanding of the separation mechanism in chromatographic experiments.