Fluorescence detection in capillary zone electrophoresis using a charge-coupled device with time-delayed integration.

Area of Science:

• Analytical Chemistry
• Biophysical Chemistry
• Spectroscopy

Background:

• Capillary zone electrophoresis (CZE) is a powerful separation technique.
• Sensitive detection methods are crucial for analyzing low concentrations of analytes.
• Fluorescence detection offers high sensitivity but requires optimized instrumentation.

Purpose of the Study:

• To develop and evaluate a novel fluorescence detection system for CZE.
• To enhance detection sensitivity and specificity using a charge-coupled device (CCD).
• To demonstrate the system's capability in differentiating analytes based on fluorescence and migration time.

Main Methods:

• A capillary electrophoresis system coupled with a CCD-based fluorescence detector was employed.
• Axial illumination of a 2-cm capillary column section was utilized.
• Two CCD readout modes were investigated: snapshot and time-delayed integration (TDI).

Main Results:

• The TDI mode enabled long exposure times for moving analyte zones.
• Differentiation of fluorescein and sulforhodamine 101 based on fluorescence emission and migration rate was achieved.
• Ultra-low detection limits were obtained: 1.2 x 10(-20) mol for FITC and (2-8) x 10(-20) mol for FITC-amino acids.

Conclusions:

• The developed CCD-based fluorescence detection system significantly enhances sensitivity in CZE.
• The TDI mode is effective for differentiating analytes by combining spectral and temporal information.
• This system offers a promising tool for high-sensitivity analysis of biomolecules and other analytes.