Development of a new capillary electrophoresis-based fibre optic sensor

Area of Science:

• Analytical Chemistry
• Optical Sensing
• Separation Science

Background:

• Conventional capillary electrophoresis (CE) systems typically use a two-reservoir configuration.
• Developing miniaturized, in situ CE sensors presents challenges in managing fluid dynamics and electrode phenomena.
• Laser-induced fluorescence (LIF) offers high sensitivity but requires integration with selective separation techniques.

Purpose of the Study:

• To develop and demonstrate a novel fluorescence-based fiber optic sensor system.
• To combine the sensitivity of LIF with the selectivity of CE in a compact, single-reservoir design.
• To overcome design challenges for in situ application of CE sensors.

Main Methods:

• Fabrication of a single-reservoir capillary electrophoresis (CE) sensor with integrated fiber optic detection.
• Implementation of design features to mitigate hydrostatic flow and gas evolution at electrodes.
• Optimization of the sensor for a balance between detection sensitivity and separation performance.
• Characterization of separation efficiency using a three-component laser dye mixture.

Main Results:

• Successful development of a compact, single-fiber optic CE sensor.
• Demonstrated feasibility of a single-reservoir design for in situ sensing.
• Achieved high separation efficiency, up to 8000 theoretical plates for a 5 cm capillary.
• Successfully separated a mixture of Rhodamine 6G, fluorescein isothiocyanate, and sodium fluorescein.

Conclusions:

• The developed CE-based sensor is feasible for in situ applications, offering selectivity, high sensitivity, and a small footprint.
• The sensor design addresses key challenges for miniaturized, remote analytical systems.
• This technology enables rapid, reusable, and remotely controlled analyses.