Stacking by electroinjection with discontinuous buffers in capillary zone electrophoresis

Area of Science:

• Analytical Chemistry
• Separation Science

Background:

• Capillary electrophoresis (CE) relies on efficient sample introduction for optimal separation.
• Traditional sample introduction methods like hydrodynamic injection and electromigration have limitations in sample stacking and salt tolerance.

Purpose of the Study:

• To investigate the efficacy of electroinjection using discontinuous buffers for enhanced sample stacking in CE.
• To compare electroinjection with discontinuous buffers to hydrodynamic injection for sample stacking and separation performance.
• To explore methods for introducing buffer discontinuity for electroinjection.

Main Methods:

• Electrospray injection using discontinuous buffer systems.
• Hydrodynamic injection for comparative analysis.
• Capillary electrophoresis for separation and analysis of stacked samples.

Main Results:

• Electoinjection with discontinuous buffers achieved superior sample stacking compared to hydrodynamic injection.
• This technique concentrated samples at the capillary tip, maximizing separation length.
• Advantages included improved sample concentration, higher plate numbers, and reduced stacking times.
• Electromigration is best for low-salt samples; high-salt samples are better suited for hydrodynamic injection with discontinuous buffers.

Conclusions:

• Electoinjection with discontinuous buffers is a powerful technique for enhancing sample stacking and separation in CE.
• The choice between electroinjection and hydrodynamic injection depends on sample salt content for optimal stacking.
• Simple methods for creating buffer discontinuities are feasible for practical application.