UTILIZATION OF TOTAL SOLUBILITY PARAMETER FOR CALCULATING RETENTION INDEXES OF ALKYLBENZENES

A new three-parameter equation is obtained that relates gas liquid chromatographic retention indices for nonpolar and weakly polar substances such as hydrocarbons to their total solubility parameters, molar volume and the number of carbon atoms by applying the expanded solubility parameters model to gas-liquid chromatography (GLC). Regression analysis is performed according to the three-parameter equation for a number of C6-C-11 alkylbenzenes on stationary phases of different polarity and at various temperatures. The regression coefficient is always higher than 0.9995 and the standard deviation lower than 3.3 i.u. For isomers, the equation is simplified to a two-parameter equation and the correlations between retention indices, total solubility parameters and molar volume are excellent. Regression analysis shows that the approach successfully predicts the retention indices of alkylbenzenes on polar and non-polar stationary phases.