Surface plasmon resonance detection for capillary electrophoresis separations.

Area of Science:

• Analytical Chemistry
• Biomedical Engineering
• Sensor Technology

Background:

• Capillary electrophoresis (CE) is a powerful separation technique.
• On-line detection methods for CE are crucial for real-time analysis.
• Miniaturized sensors offer advantages in sensitivity and integration.

Purpose of the Study:

• To develop a miniaturized surface plasmon resonance (SPR) sensor for on-line detection in capillary electrophoresis.
• To demonstrate the sensor's capability for detecting high refractive index materials and proteins.
• To optimize the system for enhanced sensitivity, reproducibility, and dynamic range.

Main Methods:

• Integration of a miniaturized SPR sensor as an on-line detector for CE.
• Modification of the capillary to shield sensor electronics from high voltages.
• Utilizing an untreated gold-sensing surface for initial material detection.
• Employing a protein immobilization procedure for selective protein detection.
• Development of a hybrid buffer system for optimized protein layer deposition and analyte delivery.

Main Results:

• Successful separation and millimolar level detection of a three-component mixture using an untreated gold surface.
• Selective protein detection achieved after surface functionalization.
• Optimized hybrid buffer system facilitated efficient protein deposition and electrophoretic delivery.
• The detection system exhibited 15% reproducibility and a dynamic range of 3 orders of magnitude.
• Achieved a detection limit of 2 femtomoles for immunoglobulin G (IgG).

Conclusions:

• The miniaturized SPR sensor serves as an effective on-line detector for capillary electrophoresis.
• The system demonstrates versatility, enabling detection of both small molecules and proteins.
• The developed method offers high sensitivity, good reproducibility, and a wide dynamic range for protein analysis.