The use of shape - selective stationary phases in GC . Part 1 : Cyclodextrin phases

Cyclodextrin phases are one of the most interesting geometry selective stationary phase in GC. 'beyare outstanding in their ability to separate isomeric and enantiomeric compounds. Two examples of the separation of cyclic compounds on cyclodextrins are given. The combination of chiral and achiral phases in series coupled columns is a useful tool for complicate separation and identification problems. INTRODUCTION During the last few years the interest in analysis of isomeric compounds of complex mixtures (flavours, fragrances, foods, biological and environmental samples) has been steadily growing. But the use of GC stationary phases on the basis of classical interaction forces offers only limited possibilities for the separation of isomeric compounds with similar properties, even if capillary columns with a high efficiency are used. This requires the study of the separation properties and the potential of so-called shape-selective stationary phases. It is not easy to give a proper definition of shape-selective stationary phases. In this paper in a simplified way we assume that by using this type of stationary phases the geometry of the molecules which have to be separated .is the predominant factor f o r the retention and the separation, too. TABLE 1. Shape-selective stationary phases in GC