Temperature dependence of the Kováts retention index. The entropy index

M. Görgényi, Jo Dewulf, Herman Van Langenhove

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

According to a novel equation, the temperature dependence of the Kováts retention index, dI/dT is proportional to the difference of the Kováts retention index, I, and the new entropy index, I(S), defined similarly as the retention index, but based on solvation entropy instead of the free energy of solvations. The new relationship was tested with the experimental retention and thermodynamic data published by Kováts and coworkers for 32 compounds on 6 different stationary phases. Very good correlations (r > 0.99) were observed for dI/dT versus (I - I(S)) and dI/dT versus δΔCp, the molar heat capacity difference of the solute and the hypothetical n-alkane, which has the same retention index as the solute. Deviations in the dI/dT versus δΔCp relationship were observed only for alcohols, suggesting a different solvation mechanism for alcohols as compared with other compounds.

Original languageEnglish
Pages (from-to)84-90
Number of pages7
JournalJournal of Chromatography A
Volume1137
Issue number1
DOIs
Publication statusPublished - Dec 22 2006

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Solvation
Entropy
Alcohols
Temperature
Alkanes
Thermodynamics
Hot Temperature
Free energy
Specific heat

Keywords

  • Entropy index
  • Entropy of solvation
  • Kováts retention index
  • Molar heat capacity of solvation
  • Temperature dependence of retention index

ASJC Scopus subject areas

  • Analytical Chemistry

Cite this

Temperature dependence of the Kováts retention index. The entropy index. / Görgényi, M.; Dewulf, Jo; Van Langenhove, Herman.

In: Journal of Chromatography A, Vol. 1137, No. 1, 22.12.2006, p. 84-90.

Research output: Contribution to journalArticle

Görgényi, M. ; Dewulf, Jo ; Van Langenhove, Herman. / Temperature dependence of the Kováts retention index. The entropy index. In: Journal of Chromatography A. 2006 ; Vol. 1137, No. 1. pp. 84-90.
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