Cyclic oligomers of several D-(+)-glucopyranose units used in chiral HPLC and CE separations; popular ones are named α-, β-, and γ-cyclodextrins; they have a truncated cone shape, a relatively hydrophobic cavity, and primary and secondary hydroxyl groups at their ends; they separate on the basis of differential inclusion of enantiomers; modified cyclodextrins with derivatized hydroxyl groups also are used for selectivity modification.