Quantitation in chiral capillary electrophoresis: theoretical and practical considerations

Area of Science:

• Analytical Chemistry
• Separation Science

Background:

• Capillary electrophoresis (CE) offers advanced capabilities for stereoselective analysis.
• Traditional resolution factors (Rs) from HPLC are less effective for CE due to differing peak shapes.

Purpose of the Study:

• To address the theoretical and practical aspects of quantitating peak separation in chiral CE.
• To propose and validate new metrics for assessing chiral separations in CE.

Main Methods:

• Evaluation of the resolution factor (Rs) for chiral separations in CE.
• Introduction and application of relative chiral separation (RCS) and percent chiral separation (% CS) factors.
• Method development using maltodextrins as chiral selectors.
• Stereoselective analysis of coumarinic anticoagulant drugs and ibuprofen.

Main Results:

• The resolution factor (Rs) is of limited value for assessing chiral separations in CE.
• Relative chiral separation (RCS) and percent chiral separation (% CS) are advocated as superior metrics.
• Maltodextrin-based chiral selectors enable effective stereoselective analysis.
• Enantiomeric excess determinations down to 1% optical contamination are feasible with CE.
• Precise stereoselective determinations are possible near the detection limit with optimized sample loading.

Conclusions:

• New quantitative metrics (RCS and % CS) enhance chiral separation assessment in CE.
• CE, particularly with maltodextrin selectors, provides a powerful platform for precise stereoselective analysis.
• The study demonstrates CE's capability for sensitive enantiomeric excess determination.