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arXiv · 2202.08598

Enhancement of photoacoustic spectroscopy with sorption enrichment for ppt-level benzene detection

Juho Karhu·Tuomas Hieta
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Abstract

A real time trace gas detector for benzene is demonstrated. The measurement system takes an advantage of modest enrichment through short adsorption periods to reach a ppt-level detection limit with a sampling cycle of 90 s, which includes sample adsorption, desorption and a spectroscopic measurement. Benzene is collected on Tenax TA sorbent for 30 s and then detected from the enriched samples with photoacoustic spectroscopy. A high sensitivity is achieved using cantilever-enhanced photoacoustic spectroscopy and a continuous-wave quantum cascade laser emitting at the wavelength 14.8 $\mu$m, which corresponds to the absorption wavelength of the strongest benzene infrared band. We reach a detection limit of 150 ppt of benzene, over one sampling cycle. Interference from humidity and other common petrochemicals is evaluated.

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Juho Karhu, Tuomas Hieta. 2022-02-17. Enhancement of photoacoustic spectroscopy with sorption enrichment for ppt-level benzene detection. https://doi.org/10.1364/ao.450407

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