Problems with reproducibility of retention data on capillary columns with hydrocarbon C87 as the stationary phase

The reproducibility of retention data on hydrocarbon C87 stationary phase coated on soda lime glass capillary columns was systematically studied For mixtures of n-alkanes and of alkylbenzenes it was found that the selectivity of the stationary phase is higher and the retention indices of alkylbenzenes and their temperature coefficients are higher compared to those obtained on OV-101. The reproducibility of the column preparation was good, the differences in retention indices measured on several columns being of the order of several decimals of index units. The columns were stable at lower temperatures (100, 120°C) within a certain time interval (14 days). In the course of longer measurements, the stationary phase slowly increases in polarity; a rapid change in polarity was observed at elevated temperatures (180 °C)