The columns used by Frank et al. were 20 m long, 300 m I.D. and were pretreated with colloidal silicic acid to stabilize the film of stationary phase. The columns were coated with 0.15% solution of the stationary phase in chloroform using the static method of coating (the different methods of coating capillary columns will be described later). Prior to use, each column was conditioned at 175 C in a stream of hydrogen. The separation of 17 N-penatfluoropropionyl d,l-amino acids on N-propionyl-l-valine t-butylamide polysiloxane is shown in figure 39. It is seen that the separation is complete in about 30 minutes, a much faster analysis than that obtained by Gil-Av. It was also found that although the minimal column operating temperature was 90 C, the column could be programmed up to 175 C without column deterioration.

Courtesy of Supelco Inc.

Figure 39. The Separation of 17 N-Penatfluoropropionyl D,L-Amino Acids on the Stationary Phase N-Propionyl-L-Valine t-Butylamide

As a result of the introduction of the thermally stable polysiloxane chiral stationary phases by Frank et al., the development of chiral GC gained momentum. As will be seen in due course many other thermally stable chiral stationary phases have since been introduced.