Recent progress of online sample preconcentration techniques in microchip electrophoresis

Area of Science:

• Analytical Chemistry
• Separation Science
• Microfluidics

Background:

• Microchip electrophoresis (MCE) offers high-speed, high-resolution separations with low reagent consumption.
• A major limitation of MCE is its low-concentration sensitivity, hindering the detection of trace analytes.
• Online sample preconcentration techniques are crucial for overcoming sensitivity limitations in MCE.

Purpose of the Study:

• To review recent advancements in online sample preconcentration techniques for Microchip Electrophoresis (MCE).
• To categorize these techniques into dynamic and static methods.
• To summarize their applications and sensitivity enhancement factors in MCE.

Main Methods:

• Categorization of online preconcentration techniques into dynamic (field amplified stacking, ITP, sweeping, focusing) and static (SPE, filtration) methods.
• Review of the integration of these techniques with MCE on a single planar substrate.
• Compilation of comprehensive tables detailing applications and sensitivity enhancement factors.

Main Results:

• Dynamic techniques like field amplified stacking, ITP, sweeping, and focusing are readily applicable to MCE, providing effective analyte enrichment.
• Static techniques, including solid-phase extraction (SPE) and filtration, can be combined with MCE.
• Static preconcentration methods offer extremely high preconcentration efficiency compared to dynamic methods.

Conclusions:

• Online sample preconcentration is vital for enhancing detection sensitivity in MCE.
• Both dynamic and static preconcentration strategies offer distinct advantages for MCE applications.
• The reviewed techniques provide significant improvements for trace analyte detection in MCE.