CYCLODEXTRIN DERIVATIVES IN THE GAS-CHROMATOGRAPHIC SEPARATION OF RACEMIC MIXTURES OF VOLATILE COMPOUNDS .7. THE USE OF 2,6-DI-O-METHYL-3-O-PENTYL-BETA-CYCLODEXTRIN DILUTED IN PHASES WITH DIFFERENT POLARITY INTHE SEPARATION OF RACEMATES IN COMPLEX-MIXTURES

In the GC separation of volatile racemates, cyclodextrin (CD) derivati ves may be used either as such or diluted in polysiloxane. If diluting phases with different polarity are used, different interactions and a s a consequence a different retention of each component in a complex m ixture are produced. The combination of the retention indices from col umns coated with a CD derivative diluted in different polysiloxane pha ses makes it possible to locate and to identify unambigously the enant iomers of an optically active compound in a complex mixture and hence from their areas to determine directly the enantiomeric excess (e.e.). Some examples in the fields of essential oils and aromas illustrate t he abilities of 2,6-di-O-methyl-3-O-pentyl-beta-CD diluted with differ ent phases (PS-347.5, PS-086, OV-1701 and OV-1701-OH) to evaluate the e.e. of one or more optically active compounds in a complex mixture.