Online sample preconcentration techniques in nonaqueous capillary and microchip electrophoresis

Area of Science:

• Analytical Chemistry
• Separation Science

Background:

• Electrophoresis, including capillary and microchip formats, suffers from low detection sensitivity.
• Online sample preconcentration is a key strategy to improve sensitivity in electrophoretic methods.
• Existing reviews primarily focus on aqueous background electrolytes, leaving a gap for nonaqueous systems.

Purpose of the Study:

• To provide a comprehensive overview of online preconcentration techniques for nonaqueous capillary and microchip electrophoresis.
• To consolidate advancements in this specific area over the past two decades.
• To highlight the importance of these techniques for enhancing detection limits.

Main Methods:

• Literature review of online preconcentration techniques in nonaqueous capillary and microchip electrophoresis.
• Focus on sample stacking, isotachophoresis, and micellar-based stacking strategies.
• Inclusion of multi-stacking approaches for nonaqueous electrophoresis.

Main Results:

• Identified and categorized various online preconcentration techniques applicable to nonaqueous electrophoresis.
• Demonstrated the evolution and development of these methods over the last 20 years.
• Highlighted the effectiveness of sample stacking, isotachophoresis, and micellar stacking in nonaqueous environments.

Conclusions:

• Online preconcentration techniques are crucial for overcoming sensitivity limitations in nonaqueous capillary and microchip electrophoresis.
• This review offers the first consolidated overview of these techniques, guiding future research.
• Further development in multi-stacking strategies holds promise for even greater sensitivity enhancements.