We are extending laser absorption spectroscopy towards the on-line detection of volatile organic compounds (VOCs) in breath. This has great potential for non-invasive point-of-care (PoC) diagnostics and personalized medicine. The custom-build spectrometer leverages on extended-tuning quantum-cascade (QC-XT) laser and our tailored icw-laser driver. An ongoing collaboration with the Children's University Hospital Zurich, in the framework of Zurich Exhalomics, will address potential Asthma biomarkers in exhaled breath.


Figure 1: Selective VOC analysis using a Vernier-type quantum-cascade laser (QCL) as an electrically tunable multi-wavelength ligth source. This emerging class of lasers provides access to several spectral windows by discrete Vernier tuning (“switching”) and continuous coverage within these windows (“scanning”). This enables the rapid acquisition of high-resolution spectra from six individual spectral windows, distributed over a wide range from 1063 to 1102 cm−1.


Within the EU-project VOCORDER our team develops one of the key optical components for the targeted breath analyzer. Further advancing the capability of our iSC-MPC should result in a compact and portable solution that allows for long optical path lengths, which would enhance the sensitivity of the sensor.

Acetone & Ethanol Analytics

Figure 2: Acetone detection in the human breath.

Figure 3: SI-traceable alcohol analyzer, developed for METAS.


  • Brechbühler, R. et al., Rapid Detection of Volatile Organic Compounds by Switch–Scan Tuning of Vernier Quantum-Cascade Lasers, Anal. Chem. 95(5), 2857–2864, 2023.
    Publication Link 

  • Selaković, M. et al., Analysis of Breath-related Volatile Organic Compounds with Laser Absorption Spectroscopy, Chimia, 77, 785, 2023.
    Publication Link

  • Tuzson, B. et al., Highly Selective Volatile Organic Compounds Breath Analysis Using a Broadly-Tunable Vertical-External-Cavity Surface-Emitting Laser, Anal. Chem. 89, 12, 6377–6383, 2017.
     Publication Link

  • Bovey, F. et al., Breath acetone as a marker of energy balance: an exploratory study in healthy humans, Nutr. & Diabetes, 8:50, 2018.
    Publication Link

  • Aseev, O. et al., High-precision ethanol measurement by mid-IR laser absorption spectroscopy for metrological applications, Opt. Express, 27(4), 53145315, 2019.
    Publication Link