TY - JOUR A1 - Escher, Lukas A1 - Rück, Thomas A1 - Jobst, Simon A1 - Pangerl, Jonas A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - Photodissociation-Driven Photoacoustic Spectroscopy with UV-LEDs for Ozone Detection JF - Photoacoustics N2 - This study presents the development and evaluation of a UV-LED based photoacoustic (PA) measurement system for ozone (O3) detection to demonstrate its potential for low-cost and accurate sensing while for the first time addressing the importance of photodissociation for PA signal generation for O3 in the UV range. With a detection limit of 7.9 ppbV, the system exhibits a significant advancement over state-of-the-art UV-PA O3 detection and is on par with laser-based setups. Following a novel discussion of the PA signal arising from photodissociation and its products, cross-sensitivity effects due to environmental factors such as temperature and gas composition were systematically analyzed. A digital twin driven compensation for these influences was implemented and evaluated. Despite the challenges associated with modeling the effects of H2O and CO2, the PA system shows considerable potential, though further studies in real world applications must be conducted. KW - Photoacoustic spectroscopy KW - UV-LED KW - Ozone KW - Photodissociation KW - Cross-sensitivity Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-80076 SN - 2213-5979 N1 - Corresponding author der OTH Regensburg: Lukas Escher VL - 43 PB - Elsevier BV ER - TY - INPR A1 - Pangerl, Jonas A1 - Sukul, Pritam A1 - Rück, Thomas A1 - Escher, Lukas A1 - Miekisch, Wolfram A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - Photoacoustic Trace-Analysis of Breath Isoprene and Acetone Via Interband- and Quantum Cascade Lasers N2 - This research presents two laser-based photoacoustic approaches for analyzing exhaled breath isoprene and acetone. The integration of a PTR-ToF-MS as a reference device ensured the reliability and accuracy of the PAS systems that is based on an ICL for isoprene and a QCL for acetone detection. The calibration yielded limits of detection of 26.9 ppbV and 1.7 ppbV, respectively, and corresponding normalized noise equivalent absorption coefficients (NNEAs) of 5.0E-9 Wcm-1Hz-0.5 and 4.9E-9 Wcm-1Hz-0.5. Laboratory as well as real breath sample measurements from alveolar breath revealed a robust system performance, with only one outlier within the static isoprene measurements. However, discrepancies emerged under dynamic breath sampling conditions, emphasizing the need for further optimization. Especially by knowing the dynamic nature and endogenous origin of exhaled isoprene our findings highlight the potential of breath analysis for non-invasive physio-metabolic and pathophysiological monitoring towards point-of-care devices. KW - photoacoustic spectroscopy KW - breath analysis/profiling KW - real-time mass spectroscopy KW - isoprene KW - acetone Y1 - 2024 U6 - https://doi.org/10.2139/ssrn.4834735 PB - Elsevier / SSRN ER - TY - JOUR A1 - Pangerl, Jonas A1 - Sukul, Pritam A1 - Rück, Thomas A1 - Escher, Lukas A1 - Miekisch, Wolfram A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - Photoacoustic trace-analysis of breath isoprene and acetone via interband- and Quantum Cascade Lasers JF - Sensors and Actuators: B. Chemical N2 - This research presents two laser-based photoacoustic approaches for analyzing exhaled breath isoprene and acetone. The integration of a PTR-ToF-MS as a reference device ensured the reliability and accuracy of the photoacoustic systems that is based on an ICL for isoprene and a QCL for acetone detection. The calibration yielded limits of detection of 26.9 ppbV and 1.7 ppbV, respectively, and corresponding normalized noise equivalent absorption coefficients (NNEAs) of 5.0E-9 Wcm 1Hz 0.5 and 4.9E-9 Wcm 1Hz 0.5. Laboratory as well as real breath sample measurements from alveolar breath revealed a robust system performance, with only one outlier within the static isoprene measurements. However, discrepancies emerged under dynamic breath sampling conditions, emphasizing the need for further optimization. Especially by knowing the dynamic nature and endogenous origin of exhaled isoprene our findings highlight the potential of breath analysis for non-invasive physio-metabolic and pathophysiological monitoring towards point-of-care devices KW - Photoacoustic spectroscopy KW - Breath analysis/profiling KW - Real-time mass spectrometry KW - Isoprene KW - Acetone Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-77024 N1 - Corresponding author der OTH Regensburg: Jonas Pangerl VL - 424 PB - Elsevier ER - TY - JOUR A1 - Rück, Thomas A1 - Pangerl, Jonas A1 - Escher, Lukas A1 - Jobst, Simon A1 - Müller, Max A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - Kinetic cooling in mid-infrared methane photoacoustic spectroscopy: A quantitative analysis via digital twin verification JF - Photoacoustics N2 - This study presents a detailed quantitative analysis of kinetic cooling in methane photoacoustic spectroscopy, leveraging the capabilities of a digital twin model. Using a quantum cascade laser tuned to 1210.01 cm⁻¹, we investigated the effects of varying nitrogen-oxygen matrix compositions on the photoacoustic signals of 15 ppmV methane. Notably, the photoacoustic signal amplitude decreased with increasing oxygen concentration, even falling below the background signal at oxygen levels higher than approximately 6 %V. This phenomenon was attributed to kinetic cooling, where thermal energy is extracted from the surrounding gas molecules rather than added, as validated by complex vector analysis using a previously published digital twin model. The model accurately reproduced complex signal patterns through simulations, providing insights into the underlying molecular mechanisms by quantifying individual collision contributions. These findings underscore the importance of digital twins in understanding the fundamentals of photoacoustic signal generation at the molecular level. Y1 - 2024 U6 - https://doi.org/10.1016/j.pacs.2024.100652 VL - 40 PB - Elsevier ER -