Recent progress of on-line sample preconcentration techniques in microchip electrophoresis

Area of Science:

• Analytical Chemistry
• Separation Science
• Microfluidics

Background:

• Microchip electrophoresis (MCE) offers miniaturized separation capabilities.
• Enhancing detection sensitivity in MCE is crucial for trace analysis.
• On-line sample preconcentration is key to improving MCE sensitivity.

Purpose of the Study:

• To review recent developments in on-line sample preconcentration for MCE.
• To categorize preconcentration techniques based on their underlying principles.
• To highlight methods offering improved sensitivity, ease of use, and speed.

Main Methods:

• Focus on preconcentration techniques utilizing discontinuous buffer systems.
• Categorization based on field strength-induced or chemically induced migration velocity changes.
• Review of techniques including field-amplified sample stacking, isotachophoresis, transient-isotachophoresis, sweeping, transient-trapping, and dynamic pH junction.

Main Results:

• On-line preconcentration significantly enhances MCE detection sensitivity.
• Discontinuous buffer systems offer effective preconcentration with simple procedures.
• Field strength- and chemically induced methods provide diverse strategies for analyte enrichment.

Conclusions:

• On-line sample preconcentration is vital for advancing MCE applications.
• Techniques based on migration velocity changes are particularly effective.
• Recent advancements offer practical solutions for sensitive and efficient MCE analysis.