Document Detail


Solute-solvent interaction parameters by gas chromatography.
MedLine Citation:
PMID:  15387188     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Gas-liquid distribution coefficients at ideal dilution in non-volatile solvents can be measured by gas chromatography. The numerical value of a coefficient depends on the choice of the concentration unit in the solvent and in the gas phase. The relationships between different coefficients characterizing gas-liquid equilibria are discussed and summarized. Coefficients determined at several temperatures permit calculation of the standard chemical potential difference of the solute with the ideal gas phase as reference as a function of temperature, the g-SPOT. Following the proposal of Kirchhoff the latter can be formulated as an equation with three constants. As in the gas phase the molecules of the solute have no interacting partners, the three constants, deltaH, deltaS and deltaC, characterize the interaction between solvent and solute molecules. They will be called the "solute-solvent interaction parameters". In the same system the values of these parameters depend on the choice of the distribution coefficient. Five different distribution coefficients result five sets of interaction parameters. It is shown that conversion of a parameter set to another implies additive corrections independent of the nature of the solute. If g-SPOT-s are measured in a series of solvents, the data may be used to calculate the corresponding liquid-liquid partition coefficients by electing one of the solvents as reference (l-SPOT). The corresponding "relative interaction parameters" can be calculated by simple substraction. In a second chapter the precautions are summarized, necessary for gas chromatographic determination of distribution coefficients and examples are given for interaction parameters in different systems. It is concluded that there are significant differences between g-SPOT-s related to different distribution coefficients. On the other hand, differences between l-SPOT-s are negligible.
Authors:
Ervin sz Kováts; György Fóti; András Dallos
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of chromatography. A     Volume:  1046     ISSN:  0021-9673     ISO Abbreviation:  J Chromatogr A     Publication Date:  2004 Aug 
Date Detail:
Created Date:  2004-09-24     Completed Date:  2005-03-24     Revised Date:  2009-01-15    
Medline Journal Info:
Nlm Unique ID:  9318488     Medline TA:  J Chromatogr A     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  185-202     Citation Subset:  IM    
Affiliation:
Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland. ervin.kovats@epfl.ch
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MeSH Terms
Descriptor/Qualifier:
Chromatography, Gas / methods*
Solvents / chemistry*
Thermodynamics
Chemical
Reg. No./Substance:
0/Solvents

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