CONSIDERATIONS ON THE DEPENDENCE OF GAS-LIQUID-CHROMATOGRAPHIC RETENTION OF N-ALKANES WITH THE CARBON NUMBER

The contributions to the free energy change involved in the chromatogr aphic retention of n-alkanes, which are functions of the solute chain length, are discussed with the aid of recent advances in chain statist ics. In the context of a simplified theoretical analysis, a discussion is promoted on the molecular nature of the observed slight deviations from linearity of ln t(R)' vs. n. A non-linear function ln t(R)'(n) i s derived from the application of the generalized Van der Waals fluid partition function to the liquid stationary phase. The excluded volume , particularly its dependence on n, is analyzed through the theory of Flory for dilute solutions of chain molecules. (C) 1998 Elsevier Scien ce B.V. All rights reserved.