STRUCTURAL FACTORS AFFECTING THE ENANTIOMERIC SEPARATION OF BARBITURATES AND THIOBARBITURATES WITH A CHIRAL SIDE-CHAIN BY VARIOUS BETA-CYCLODEXTRIN SUPPORTS - EFFECTS OF THE PRESENCE OF HYDROXYPROPYL SUBSTITUENTS ON THE CHIRAL SELECTOR

The chromatographic separation of barbiturate and thiobarbiturate enan tiomers on beta-cyclodextrin (beta-CD) HPLC columns was studied. The e ffect of the nature of the side-chain bearing the chiral centre was ex amined. The stationary phases used were of two types, commercial with native beta-CD or hydroxypropyl-beta-CD residues linked to silica and laboratory-made with beta-CD polymers adsorbed on silica. The chiral r ecognition of the studied compounds is mainly dependent on the presenc e of hydroxypropyl substituents in the beta-CD cavity.