Chiral stationary phases cydodextrins

Cyclodextrins. As indicated previously, the native cydodextrins, which are thermally stable, have been used extensively in liquid chromatographic chiral separations, but their utility in gc applications was hampered because their highly crystallinity and insolubility in most organic solvents made them difficult to formulate into age stationary phase. However, some functionalized cyclodextrins form viscous oils suitable forge stationary-phase coatings and have been used either neat or diluted in a polysiloxane polymer as chiral stationary phases for gc (119). Some of the derivatized cyclodextrins which have been adapted to gc phases are 3-O-acetyl-2,6-di-O-pentyl, 3-0-butyryl-2,6-di-O-pentyl,... 

Limitations with the chiral selectivity of the native cydodextrins fostered the development of various functionalized cydodextrin-based chiral stationary phases, including acetylated (82,83), sulfated (84), 2-hydroxypropyl (85), 3,5-dimethylphenylcarbamoylated (86) and... 

The majority of the chiral stationary phases are silica based. The most commonly used phases have cyclodextrins linked to the silica. Cydodextrins are oligosaccharides with D-glucopyranoside units hnked to construct cavities of different sizes (Figure 3.20). 

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