A Microfluidic, Flow-Through, Liquid Reagent Fluorescence Sensor Applied to Oxygen Concentration Measurement

Area of Science:

• Analytical Chemistry
• Chemical Sensing
• Microfluidics

Background:

• Accurate dissolved oxygen measurement is crucial for environmental monitoring.
• Traditional methods can be cumbersome and have limitations in continuous monitoring.
• Microfluidic systems offer miniaturization and reduced reagent consumption.

Purpose of the Study:

• To present and demonstrate a microfluidic fluorescent chemical sensing system.
• To develop a sensor for the measurement of dissolved oxygen in water.
• To showcase a system with low reagent and sample consumption for continuous monitoring.

Main Methods:

• Utilized on-line mixing of a fluorescent reagent with the analyzed sample.
• Measured the fluorescence decay time of the mixture.
• Constructed the system using silica capillaries and optical fibers.

Main Results:

• Demonstrated a microfluidic sensor for dissolved oxygen measurement.
• Achieved very low consumption of reagent (mL/month) and sample (L/month).
• Enabled continuous on-line measurements with a variety of fluorescent reagents.

Conclusions:

• The proposed microfluidic system is suitable for continuous on-line dissolved oxygen monitoring.
• The flow-through design minimizes issues like bleaching and heating.
• High signal amplitudes allow for low-noise detection and use of reagents with nanosecond lifetimes.