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

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.

8 pages, 7 figures

References in corpus (1)

• Broadband photoacoustic spectroscopy of ${}^{14}{\text{CH}}_4$ with a high-power mid-infrared optical frequency comb