Courtesy of Supelco

The a-DEXª capillary column was 30 m long, 0.25 mm I.D. and carried a film of stationary phase 0.25 mm thick. The operating temperature was 90ûC, helium was used as the mobile phase at a flow velocity of 30 cm/s.

Figure 28. Chromatogram of a Test Mixture on a Permethylated a-Cyclodextrin Stationary Phase

The retention of the different solutes illustrate the fundamental selective character of the stationary phase. The relative elution times of the normal paraffins (which are solely retained by dispersive interactions with the stationary phase) indicate a moderate dispersive character, but it is interesting to note that the propane diols are eluted between the C10 and C11 hydrocarbons.