Chiral HPLC Separation on Derivatized Cyclofructan Versus Cyclodextrin Stationary Phases

Abstract

Cyclodextrins (CDs) and cyclofructans (CFs) are chiral cyclic oligosaccharides. While β-CD is composed of seven glucopyranose units forming rigid cavity, hydrophobic inside, CF6 and CF7, contain six and seven fructofuranose units, respectively, creating a polar crown ether core. These basic structures can be easily derivatized to form even more potential chiral selectors that enable enantioselective separation of various chiral compounds. Chiral stationary phases (CSPs) based on CFs and CDs that were derivatized with the same derivatization group, either dimethylphenyl or R-naphthylethyl, were compared. A set of analytes with different interaction possibilities was used for characterization of retention and enantioseparation abilities of these CSPs in normal separation mode of HPLC. The results showed that both cyclic oligosaccharide structure and derivatization group influenced the retention/separation behavior of analytes. Complementary enantioseparations were obtained for some analytes.

Keywords:

• Chiral separation
• Cyclodextrin
• Cyclofructan
• HPLC

Acknowledgments

The Ministry of Education, Youth and Sports of the Czech Republic, Project Kontakt AM 2010 LH11018; the Grant Agency of the Charles University in Prague, Project No. 356411; and the long-term project MSM0021620857 are gratefully acknowledged for the financial support.

Notes

Note. k ₁, retention factor of the first eluted atropoisomer; α, selectivity; R, resolution.

Note. k ₁, retention factor of the first eluted enantiomer; α, enantioselectivity; R, enantioresolution; n.e., no elution within three hours.

Note. k ₁, retention factor of the first eluted atropoisomer; α, selectivity; R, resolution.

^a Slight indication of chiral separation.

Note. k ₁, retention factor of the first eluted enantiomer; α, enantioselectivity; R, enantioresolution.