Mid-IR evanescent-field fiber sensor with enhanced sensitivity for volatile organic compounds

Area of Science:

• Analytical Chemistry
• Environmental Science
• Materials Science

Background:

• Growing concerns about air pollution's health and environmental impacts drive demand for effective volatile organic compounds (VOCs) sensor technologies.
• Current VOC monitoring methods are often limited by size, cost, or the inability to selectively detect individual compounds in the gas phase.
• Selective gas-phase VOC detection remains a significant challenge in environmental monitoring.

Purpose of the Study:

• To propose a novel method and device for enhanced detection of volatile organic compounds (VOCs).
• To overcome the limitations of existing VOC sensors by enabling selective and sensitive detection.
• To improve the performance of fiber-optic spectroscopy for VOC analysis.

Main Methods:

• Development of a mid-IR evanescent-wave fiber-optic spectroscopy sensor.
• Coating the fiber surface with nano-porous microparticles to enhance analyte molecule concentration via capillary condensation.
• Utilizing the nano-porous structure for rapid diffusion and concentration of VOC analytes at the fiber surface.
• Measuring different VOCs and analyzing enhanced sensitivity using a custom-built gas cell.

Main Results:

• The proposed sensor design significantly increases the concentration of VOC analytes near the evanescent field.
• Demonstrated enhanced sensitivity of the fiber-optic sensor compared to an uncoated fiber.
• Successful measurement of different VOCs, validating the sensor's performance.

Conclusions:

• The novel mid-IR evanescent-wave fiber-optic spectroscopy method with nano-porous microparticle coating effectively enhances VOC detection.
• This technology offers a promising solution for selective and sensitive monitoring of volatile organic compounds.
• The developed sensor represents a significant advancement in air quality monitoring and health risk assessment.