Narrow sample channel injectors for capillary electrophoresis on microchips

Area of Science:

• Analytical Chemistry
• Microfluidics
• Separation Science

Background:

• Microchip electrophoresis (MCE) commonly uses cross, double-tee, or tee injectors for sample introduction.
• Existing injector designs feature uniform channel dimensions at the injection intersection, potentially limiting performance.

Purpose of the Study:

• To introduce and evaluate novel cross and tee injectors with narrow sample channels for MCE.
• To demonstrate improvements in resolution, efficiency, sensitivity, and operational simplicity.

Main Methods:

• Fabrication of poly(dimethylsiloxane)-glass microchips with integrated narrow-channel cross and tee injectors.
• Implementation of these injectors in parallel microchip electrophoresis systems.
• Performance evaluation based on resolution, column efficiency, sensitivity, and operational requirements.

Main Results:

• Narrow-channel cross injectors significantly improved resolution, column efficiency, and sensitivity.
• Both narrow-channel cross and tee injectors eliminated the need for leakage control during injection and separation.
• Narrow-channel tee injectors achieved good resolution, overcoming limitations of conventional designs.
• Multiplexed systems using narrow-channel tee injectors achieved the theoretical limit of N+2 reservoirs.

Conclusions:

• Narrow sample channel injectors represent a significant advancement in microchip electrophoresis technology.
• These injectors offer enhanced performance, simplified operation, and reduced system complexity.
• The developed injectors are suitable for high-performance, user-friendly microchip CE systems.