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Large-volume sample stacking in nonaqueous capillary electrophoresis using alcoholic run buffers
Jaeho Jang1, Yoon-Mo Koo, Doo Soo Chung
1School of Chemistry, Seoul National University, Seoul, Korea.
Journal of Capillary Electrophoresis and Microchip Technology
|May 22, 2003
Summary
A new method enables large-volume sample stacking for organic compounds using alcohol buffers to suppress electroosmotic flow. This technique achieves low nanomolar detection limits for anions in capillary electrophoresis.
Area of Science:
- Analytical Chemistry
- Separation Science
- Capillary Electrophoresis
Background:
- Traditional capillary electrophoresis (CE) methods face challenges in achieving low detection limits for weakly acidic organic compounds due to limited sample volumes.
- Large-volume sample stacking is crucial for enhancing sensitivity in the analysis of trace analytes.
- Suppressing electroosmotic flow (EOF) is a key strategy for enabling effective sample stacking, particularly for anionic analytes.
Purpose of the Study:
- To develop a straightforward method for stacking extremely large volumes of sample solutions containing weakly acidic organic compounds.
- To enable the analysis of anionic analytes against the electroosmotic flow using a simple capillary electrophoresis setup.
- To achieve low nanomolar detection limits for organic anions.
Main Methods:
- Utilized alcohols (methanol, ethanol, 1-propanol) as run buffer solvents to suppress electroosmotic flow (EOF) in a bare fused-silica capillary.
- Employed a reverse voltage to allow analyte anions to migrate towards the outlet vial against the suppressed EOF.
- Performed analysis using conventional UV absorbance detection.
Main Results:
- Successfully demonstrated large-volume sample stacking for anionic analytes without the need for polarity switching.
- Achieved detection limits in the low nanomolar range for the targeted organic compounds.
- Confirmed the applicability of the developed technique with various organic solvents.
Conclusions:
- The developed method provides an effective and simple approach for large-volume sample stacking of weakly acidic organic compounds in capillary electrophoresis.
- The use of alcohol buffers to suppress EOF is a viable strategy for enhancing the sensitivity of CE analysis for anions.
- This technique offers a valuable tool for trace analysis of organic compounds, achieving high sensitivity with conventional detection methods.