Low-volume PEEK gas cell for BTEX detection using portable deep-UV absorption spectrophotometry

Area of Science:

• Analytical Chemistry
• Environmental Science
• Spectroscopy

Background:

• Indoor air quality (IAQ) monitoring is crucial for health.
• UV absorption spectrophotometry and gas chromatography are established techniques for gas molecule detection.
• Existing methods may lack portability or cost-effectiveness for widespread IAQ monitoring.

Purpose of the Study:

• To develop and evaluate a deep-ultraviolet (deep-UV) absorption spectrophotometer integrated with micro gas chromatography (μGC).
• To detect specific volatile organic compounds, namely benzene, toluene, ethylbenzene, and xylenes (BTEX).
• To assess the performance and potential applications of the developed system for IAQ analysis.

Main Methods:

• A low-volume gas cell spectrophotometer was constructed using a PolyEther Ether Ketone (PEEK) polymer tube, a portable deep-UV LED, and a photomultiplier tube.
• The detector's performance was assessed using varying concentrations of toluene in nitrogen.
• The spectrophotometer was integrated into a μGC system for analyzing BTEX mixtures.

Main Results:

• The detection unit achieved a sensitivity of 107.1 μAU/ppm and a limit of detection of 1.41 ppm for toluene.
• High-quality, well-separated chromatograms with good repeatability were obtained for BTEX molecules.
• The developed deep-UV absorption spectrophotometer demonstrated low-volume, low-cost characteristics, and ease of integration.

Conclusions:

• The integrated deep-UV absorption spectrophotometer and μGC system provides a viable tool for sensitive BTEX detection.
• The system's portability, cost-effectiveness, and performance make it suitable for indoor air quality monitoring.
• The technology holds potential for analyzing various analytes in both gas and liquid media beyond BTEX.