A microfluidic device for open loop stripping of volatile organic compounds.

Area of Science:

• Analytical Chemistry
• Environmental Science
• Chemical Engineering

Background:

• Assessing water quality necessitates the detection of volatile organic compounds (VOCs).
• Existing methods for VOC detection in water can be time-consuming and complex.
• There is a need for rapid, online monitoring systems for organic solvents in aqueous environments.

Purpose of the Study:

• To develop and demonstrate a miniaturized stripping device for fast online detection of organic solvents in water.
• To enable efficient transfer of volatile compounds from water to gas phase at room temperature.
• To integrate the device with a semiconductor gas sensor for quantitative analysis.

Main Methods:

• A microfluidic chip was designed to create an annular flow of water and nitrogen gas.
• Volatile organic compounds were transferred from the water to the gas phase within 5 seconds.
• Liquid-gas separation was achieved using side capillaries, and the gas phase was collected for analysis.
• A semiconductor gas sensor was used to quantify the concentration of VOCs.

Main Results:

• The device demonstrated efficient transfer of volatile organic compounds from water to gas phase.
• Successful detection of various organic solvents including THF, 1-propanol, toluene, ethylbenzene, benzaldehyde, and methanol was achieved.
• The system operates continuously at room temperature with low liquid flow rates (microliters per minute).

Conclusions:

• The developed miniaturized stripping device offers a fast, mobile, and inexpensive solution for online VOC detection in water.
• The system is suitable for real-time water quality assessment and can be integrated into process control systems.
• This technology facilitates efficient monitoring of organic solvents in various applications, including chemical production.