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Published on: October 27, 2020
Separation of basic and acidic compounds by capillary electrochromatography using monolithic silica capillary columns
Jiwei Hu1, Chuanhui Xie, Ruijun Tian
1College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, China.
Journal of Separation Science
|June 1, 2007
Summary
A new zwitterionic silica column offers tunable electroosmotic flow (EOF) for capillary electrochromatography (CEC). This novel stationary phase effectively separates acidic and basic compounds, reducing peak tailing for basic analytes.
Area of Science:
- Analytical Chemistry
- Separation Science
- Chromatography
Background:
- Traditional silica columns in capillary electrochromatography (CEC) often exhibit peak tailing, particularly for basic compounds.
- Controlling electroosmotic flow (EOF) is crucial for optimizing CEC separation efficiency and selectivity.
- Zwitterionic stationary phases offer unique surface charge properties that can be modulated by mobile phase conditions.
Purpose of the Study:
- To develop and characterize a novel monolithic silica column with a zwitterionic stationary phase.
- To investigate the influence of mobile phase pH on the surface charge and EOF in the prepared column.
- To evaluate the performance of the zwitterionic column for the separation of acidic and basic compounds in CEC.
Main Methods:
- Preparation of a monolithic silica column via covalent attachment of phenylalanine to a silane-modified silica monolith.
- Characterization of the zwitterionic stationary phase and its surface charge properties.
- Capillary electrochromatography (CEC) separations of acidic and basic analytes using the developed column under varying pH conditions.
Main Results:
- The zwitterionic stationary phase allowed for pH-dependent manipulation of surface charge density and EOF direction (anodic and cathodic modes).
- Effective separation of various acidic and basic compounds was achieved on the zwitterionic column.
- Peak tailing of basic compounds was significantly reduced compared to conventional silica columns at optimized buffer compositions.
Conclusions:
- The novel zwitterionic monolithic silica column provides a versatile platform for CEC separations.
- The pH-tunable EOF and the involvement of mixed interaction mechanisms (electrophoretic, hydrophobic, ion-exchange) contribute to enhanced separation performance.
- This zwitterionic column represents a promising advancement for the analysis of diverse chemical species in CEC.
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