Isothermal Gas Chromatographic Partion Coefficients of n-Alkanes, Benzene, Methylbenzenes and Chlobenzenes on Two Opposite Polarity Stationary Phases

Partition coefficients of benzene, its twelve methylbenzenes and its twelve chlorobenzenes have been estimated on two fused silica capillary columns coated with the stationary phases HP-5 and ZB-WAX at 100-180_C range. These retention data are compared to evaluate the column temperature effect, the dependence of the substituent number and the influence of the stationary phase polarity. The partition coefficient decreases with increasing column temperature in all cases, but, on the contrary, it increases with the number of methyl radicals and chlorine atoms at each stationary phase at each temperature, and it increases for the polar stationary phase. The partition coefficients of the isomers (1,2-), (1,2,3-) and (1,2,3,4-) are larger than those of the other diisomers (1,3-) and (1,4-), triisomers (1,2,4-) and (1,3,5-), and tetraisomers (1,2,3,5-) and (1,2,4,5-). Discussion in terms of physicochemical properties of these isomers is forwarded.