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On-line sample preconcentration techniques in micellar electrokinetic chromatography.
1Graduate School of Science, Himeji Institute of Technology, 3-chome 2-1, Kouto, Kamigori, Hyogo 678-1297, Japan.
Journal of Pharmaceutical and Biomedical Analysis
|December 18, 2002
Summary
This review details on-line sample concentration techniques for micellar electrokinetic chromatography (MEKC). Sample stacking and sweeping effectively enhance sensitivity by focusing analytes, overcoming limitations in capillary electrophoresis.
Area of Science:
- Analytical Chemistry
- Separation Science
Background:
- Micellar electrokinetic chromatography (MEKC) faces challenges with low concentration sensitivity due to small sample volumes and limited optical path lengths.
- This limitation hinders effective on-capillary photometric detection.
Purpose of the Study:
- To provide a comprehensive overview and practical understanding of on-line sample concentration techniques in MEKC.
- To highlight methods that enhance concentration sensitivity in capillary electrophoresis.
Main Methods:
- Focuses on two primary on-line preconcentration techniques: sample stacking and sweeping.
- Explains the mechanisms of sample stacking (ion focusing across electric field boundaries) and sweeping (analyte accumulation by pseudostationary phases).
Main Results:
- Sample stacking achieves analyte focusing by exploiting differences in migration velocities across electric field gradients.
- Sweeping effectively concentrates analytes by their accumulation within the pseudostationary phase.
Conclusions:
- Sample stacking and sweeping are effective strategies for improving concentration sensitivity in MEKC.
- The review presents various examples and applications of these techniques under diverse experimental conditions.