Correlation between retention indices and quantum-chemical descriptors of ketones and aldehydes on stationary phases of different polarity

Abstract

Kováts retention indices determined on four different capillary columns (OV-1, HP-50, DB-210 and HP-Innowax) were correlated with molecular structural parameters calculated by a semiempirical quantum-chemical method PM3. Multivariate techniques: principal component analysis and cluster analysis were applied to extract the data structure. Multiple linear regression was made in forward stepwise manner to select suitable variables in the model. Basic correlations were found between the retention indices on different columns and the molecular surface, energies of highest occupied and lowest unoccupied molecular orbitals { E(HOMO) and E(LUMO)}, polarizability, and dipole moments. These correlations provide insights into the mechanism of chromatographic retention on a molecular level. They support the view: the more polar is the stationary phase, the greater is the effect of the polarity (polarizability and dipole moment) of solute molecules on the retention phenomena.