IMPROVED METHOD FOR PREDICTION OF GAS-CHROMATOGRAPHIC RETENTION INDEXES OF C9-C-12 ALKYLBENZENES

The positive identification of higher alkylbenzene isomers is a difficult task even with a mass spectral detector. A preliminary calculative identification could serve for a better orientation in the obtained mass spectra as well as acting as a complementary and independent identification tool. An accurate equation for the prediction of retention indices of C9-C12 alkylbenzenes and their temperature coefficients, dI/dT, on OV-101 is given. The basic parameter is the molecular mass, while tuning parameters include the kind of substitution and the carbon chain of the substituents. The correlation coefficient obtained for 94 alkylbenzenes is 0.9995 and the mean standard deviation is 2.7 units. The predictive possibilities of the equation are demonstrated by inter- and extrapolative calculations of the retention indices of certain isomers with experimentally measured retention data, but without the mass spectral assignment of the positions of substituents.