The semi-empirical topological
index,
IET, was developed and optimized to describe the
chromatographic retention of alkylbenzenes on the squalane stationary phase. The simple linear regression between the
chromatographic retention and the proposed
index, for 122 alkylbenzenes studied, is of good quality (determination coefficient,
r2 = 0.9996, standard deviation, S.D. = 5.5, and leave-one-out cross-validation correlation coefficient,
). The predictive ability of
IET was also verified for stationary phases with two different polarities (SE-30 and Carbowax 20 M), and good results were obtained, especially for the stationary phase with low polarity, showing that the specific molecular interactions occur on highly polar phases. The
IET was applied to construct quantitative structure–property relationship (QSPR) models for representative properties such as boiling point, Bp(°C), octanol/water partition coefficient, log
P, van der Waals volume (
VW) and molar refractivity (
RM). Satisfactory quality QSPR models were obtained with Bp,
VW and
RM showing that the molecular size and dispersive forces are dominating factors with respect to the
chromatographic retention.