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Published on: August 14, 2019
Analysis of flavonoids by CE using capacitively coupled contactless conductivity detection
Stefan Bachmann1, Christian W Huck, Rania Bakry
1Institute of Analytical Chemistry and Radiochemistry, Leopold-Franzens University, Innsbruck, Austria.
Electrophoresis
|February 1, 2007
Summary
A new capacitively coupled contactless conductivity (C(4)D) method offers a more sensitive and accurate way to analyze flavonoids compared to UV-detection. This technique enhances the determination of these important phytochemicals.
Area of Science:
- Analytical Chemistry
- Separation Science
- Phytochemistry
Background:
- Flavonoids are crucial phytochemicals with significant biological activities.
- Existing methods for flavonoid analysis, such as indirect UV-detection in capillary electrophoresis (CE), often lack sufficient sensitivity and accuracy.
- Capacitively coupled contactless conductivity detection (C(4)D) presents a promising alternative for sensitive analyte detection.
Purpose of the Study:
- To develop and validate a sensitive CE method using C(4)D for the analysis of key flavonoids.
- To compare the performance of C(4)D with indirect UV-detection and direct UV-detection in CE for flavonoid analysis.
- To investigate the influence of glycosylation on flavonoid conductivity and apply the method for real-world sample analysis.
Main Methods:
- Development of a capillary electrophoresis (CE) method utilizing capacitively coupled contactless conductivity detection (C(4)D).
- Optimization of background electrolyte (BGE) pH and concentration for both co- and counter-electroosmotic flow (EOF) modes.
- Validation of the CE-C(4)D method, including sensitivity, linearity, and limit of detection (LOD) assessment.
- Comparative analysis against indirect UV-detection and previously published CE methods.
- Study of the effect of the sugar moiety on flavonoid conductivity using hesperetin and hesperidin.
- Application of the optimized method for the quantification of naringenin in a herbal preparation (Sinupret).
Main Results:
- The optimized CE-C(4)D method achieved approximately seven times higher sensitivity than indirect UV-detection and two times higher sensitivity than direct UV-detection.
- Lower limits of detection (LOD) were observed with C(4)D (0.12–0.21 µg/mL) compared to indirect UV-detection (0.77–1.20 µg/mL).
- C(4)D demonstrated excellent linearity (regression coefficient >0.99) due to lower baseline noise, outperforming indirect UV-detection (0.93).
- The sugar moiety in flavonoids was found to increase conductivity, as evidenced by the analysis of hesperidin versus hesperetin.
- The method successfully quantified naringenin in Sinupret, demonstrating its practical applicability.
Conclusions:
- CE with C(4)D is a highly sensitive and accurate technique for the analysis of flavonoids.
- C(4)D offers significant advantages over UV-based detection methods in CE for flavonoid quantification.
- The developed method is suitable for the determination of flavonoids in complex matrices like herbal medicines.
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