A sub-ppbv-level Acetone and Ethanol Quantum Cascade Laser Based Photoacoustic Sensor - Characterization and Multi-Component Spectra Recording in Synthetic Breath

Jonas Pangerl; Elisabeth Moser; Max Müller; Stefan Weigl; Simon Jobst; Thomas Rück; Rudolf Bierl; Frank-Michael Matysik

doi:10.1016/j.pacs.2023.100473

A sub-ppbv-level Acetone and Ethanol Quantum Cascade Laser Based Photoacoustic Sensor - Characterization and Multi-Component Spectra Recording in Synthetic Breath

Photoacoustics. 2023 Mar 16:30:100473. doi: 10.1016/j.pacs.2023.100473. eCollection 2023 Apr.

Authors

Jonas Pangerl^{1

2}, Elisabeth Moser^{1

3}, Max Müller^{1

2}, Stefan Weigl¹, Simon Jobst^{1

2}, Thomas Rück¹, Rudolf Bierl¹, Frank-Michael Matysik²

Affiliations

¹ Sensorik-ApplikationsZentrum (SappZ), Regensburg University of Applied Sciences, 93053 Regensburg, Germany.
² Institute of Analytical Chemistry, Chemo, and Biosensors, University of Regensburg, 93053 Regensburg, Germany.
³ Faculty of Informatics, Technical University of Munich, 85748 Garching, Germany.

Abstract

Trace gas analysis in breath is challenging due to the vast number of different components. We present a highly sensitive quantum cascade laser based photoacoustic setup for breath analysis. Scanning the range between 8263 and 8270 nm with a spectral resolution of 48 pm, we are able to quantify acetone and ethanol within a typical breath matrix containing water and CO₂. We photoacoustically acquired spectra within this region of mid-infra-red light and prove that those spectra do not suffer from non-spectral interferences. The purely additive behavior of a breath sample spectrum was verified by comparing it with the independently acquired single component spectra using Pearson and Spearman correlation coefficients. A previously presented simulation approach is improved and an error attribution study is presented. With a 3σ detection limit of 6.5 ppbv in terms of ethanol and 250 pptv regarding acetone, our system is among the best performing presented so far.

Keywords: Acetone; Breath analysis; Photoacoustic spectroscopy; Quantum cascade laser; Spectral simulation.