Electrokinetic chromatography employing an anionic and a cationic beta-cyclodextrin derivative

Area of Science:

• Analytical Chemistry
• Separation Science
• Chiral Chemistry

Background:

• Beta-cyclodextrin (1) is a chiral selector in capillary zone electrophoresis (CZE).
• Ionic compounds can form diastereomeric complexes with beta-cyclodextrin.
• Charged beta-cyclodextrin derivatives enhance separation capabilities.

Purpose of the Study:

• To synthesize novel charged beta-cyclodextrin derivatives.
• To evaluate their efficacy in enantiomer separation using cyclodextrin electrokinetic chromatography (CD-EKC).
• To investigate enantiomerization phenomena during separation.

Main Methods:

• Synthesis of 6-O-(2-hydroxy-3-trimethylammoniopropyl)-beta-cyclodextrin (2) and 6-O-(sulfo-n-propyl)-beta-cyclodextrin (SPE-beta-CD, 3).
• Characterization of derivatives using 1H NMR and electrospray ionization mass spectrometry (ESI-MS).
• Enantiomer separation of neutral barbiturates, chlorthalidone, terbutaline, warfarin, salbutamol, and brompheniramine via CD-EKC.

Main Results:

• Synthesized charged beta-cyclodextrin derivatives (2 and 3) with varying degrees of substitution.
• Successfully achieved enantiomer separation for a range of neutral and ionic compounds.
• Observed reversible enantiomerization of chlorthalidone below 20°C during SPE-beta-CD mediated separation.

Conclusions:

• Charged beta-cyclodextrin derivatives are effective chiral selectors in CD-EKC.
• The developed method allows for the separation of diverse chiral compounds.
• The study highlights the potential for observing enantiomerization under specific separation conditions.