Microchip capillary electrophoresis using on-line chemiluminescence detection

Area of Science:

• Analytical Chemistry
• Biochemistry
• Microfluidics

Background:

• Capillary electrophoresis (CE) is a powerful separation technique.
• Chemiluminescence (CL) detection offers high sensitivity.
• Microchip-based systems offer miniaturization and rapid analysis.

Purpose of the Study:

• To develop and evaluate a microchip-integrated capillary electrophoresis system with peroxyoxalate chemiluminescence detection.
• To separate and detect dansyl-labeled amino acids (dansyl-lysine and dansyl-glycine).
• To assess the performance characteristics, including detection limits and reproducibility.

Main Methods:

• Utilized quartz microchips with two channels and four reservoirs.
• Separated dansyl amino acids using capillary electrophoresis on the microchip.
• Employed bis[(2-(3,6,9-trioxadecanyloxycarbony)-4-nitrophenyl]oxalate as the peroxyoxalate chemiluminescent reagent.
• Detected light emission at the interface of the separation channel and reagent reservoir.

Main Results:

• Achieved a detection limit of 1 x 10(-5) M for dansyl-lysine, corresponding to a mass detection limit of approximately 0.4 fmol.
• Observed a concentration sensitivity two orders of magnitude lower than conventional CE-CL systems.
• Reported relative standard deviations of 4.2% for migration time and 4.5% for peak height for dansyl-lysine.
• Demonstrated rapid separation times within 40 seconds.

Conclusions:

• The microchip CE-CL system enables rapid separation and detection of dansyl amino acids.
• The system offers advantages in miniaturization, sample injection accuracy, and speed.
• Reproducibility requires channel conditioning and precise voltage control.
• Further optimization is needed to improve concentration sensitivity compared to conventional methods.