Fluorescence correlation spectroscopy excited with a stationary interference pattern for capillary electrophoresis

Area of Science:

• Analytical Chemistry
• Biophysical Chemistry
• Spectroscopy

Background:

• Conventional capillary electrophoresis (CE) relies on precise control of injected analyte plug dimensions for optimal separation.
• Fluorescence correlation spectroscopy (FCS) provides information about molecular dynamics and concentrations.

Purpose of the Study:

• To develop and validate a new technique, CE/patterned FCS, for electrophoretic analysis.
• To overcome the limitations of initial analyte plug length in CE.
• To enhance separation efficiency and resolution in capillary electrophoresis.

Main Methods:

• Combines capillary electrophoresis (CE) with patterned fluorescence correlation spectroscopy (patterned FCS).
• Utilizes a stationary interference pattern created by intersecting laser beams within the capillary.
• Analyzes fluctuations in fluorescence intensity to generate virtual electropherograms.

Main Results:

• Theoretically demonstrated that the power spectrum of fluorescence intensity fluctuations yields a virtual electropherogram.
• Numerical simulations predict CE/patterned FCS superiority over conventional CE for effective lengths < 1 cm.
• Experimental validation using TOTO-1-stained DNA achieved 7400 plates and 1.0 resolution with a 740 µm effective length.

Conclusions:

• CE/patterned FCS offers a robust alternative to conventional CE, independent of injection plug size.
• The technique shows significant potential for high-resolution separation of DNA fragments.
• Demonstrated experimental feasibility and performance advantages for specific applications.