Comparison of the Selectivity and Retention of β-Cyclodextrin vs. Heptakis-2,3-O-dimethyl-β-cyclodextrin LC Stationary Phases for Structural and Geometric Isomers

Both β-cyclodextrin and 2,3-methylated-β-cyclodextrin bonded stationary phases effectively separate a variety of structural and geometrical isomeric compounds in the reversed phase mode. The retention of neutral structural isomeric compounds, as well as substituted phenols and anilines, was usually longer on the methylated cyclodextrin stationary phase. Conversely, the retention of all substituted carboxylic acids was greater on the native β-cyclodextrin stationary phase. The selectivity differences between the native β-cyclodextrin and its 2,3-methylated analogue were not as great as expected for the structural isomers. In general, the structural isomer that was retained longest on the native β-cyclodextrin stationary phase also was retained longest on the 2,3-methylated cyclodextrin stationary phase. Current address: Advanced Separation Technologies, Inc., Whippany, NJ.