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- Henderson, Ben, et al.
(author)
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Laser spectroscopy for breath analysis : towards clinical implementation
- 2018
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In: Applied physics. B, Lasers and optics (Print). - : Springer Berlin/Heidelberg. - 0946-2171 .- 1432-0649. ; 124:8
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Journal article (peer-reviewed)abstract
- Detection and analysis of volatile compounds in exhaled breath represents an attractive tool for monitoring the metabolic status of a patient and disease diagnosis, since it is non-invasive and fast. Numerous studies have already demonstrated the benefit of breath analysis in clinical settings/applications and encouraged multidisciplinary research to reveal new insights regarding the origins, pathways, and pathophysiological roles of breath components. Many breath analysis methods are currently available to help explore these directions, ranging from mass spectrometry to laser-based spectroscopy and sensor arrays. This review presents an update of the current status of optical methods, using near and mid-infrared sources, for clinical breath gas analysis over the last decade and describes recent technological developments and their applications. The review includes: tunable diode laser absorption spectroscopy, cavity ring-down spectroscopy, integrated cavity output spectroscopy, cavity-enhanced absorption spectroscopy, photoacoustic spectroscopy, quartz-enhanced photoacoustic spectroscopy, and optical frequency comb spectroscopy. A SWOT analysis (strengths, weaknesses, opportunities, and threats) is presented that describes the laser-based techniques within the clinical framework of breath research and their appealing features for clinical use.
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| 2. |
- Mandon, Julien, et al.
(author)
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Exhaled nitric oxide monitoring by quantum cascade laser : comparison with chemiluminescent and electrochemical sensors
- 2012
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In: Journal of Biomedical Optics. - 1083-3668 .- 1560-2281. ; 17:1, s. 017003-
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Journal article (peer-reviewed)abstract
- Fractional exhaled nitric oxide (FENO ) is considered an indicator in the diagnostics and management of asthma. In this study we present a laser-based sensor for measuring FENO . It consists of a quantum cascade laser (QCL) combined with a multi-pass cell and wavelength modulation spectroscopy for the detection of NO at the sub-part-per-billion by volume (ppbv, 1∶10-9) level. The characteristics and diagnostic performance of the sensor were assessed. A detection limit of 0.5 ppbv was demonstrated with a relatively simple design. The QCL-based sensor was compared with two market sensors, a chemiluminescent analyzer (NOA 280, Sievers) and a portable hand-held electrochemical analyzer (MINO®, Aerocrine AB, Sweden). FENO from 20 children diagnosed with asthma and treated with inhaled corticosteroids were measured. Data were found to be clinically acceptable within 1.1 ppbv between the QCL-based sensor and chemiluminescent sensor and within 1.7 ppbv when compared to the electrochemical sensor. The QCL-based sensor was tested on healthy subjects at various expiratory flow rates for both online and offline sampling procedures. The extended NO parameters, i.e. the alveolar region, airway wall, diffusing capacity, and flux were calculated and showed a good agreement with the previously reported values.
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| 3. |
- Schmidt, Florian M., et al.
(author)
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Optical spectroscopy
- 2020. - 2
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In: Breathborne biomarkers and the human volatilome. - : Elsevier. - 9780128199671 - 9780128223970 ; , s. 221-238
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Book chapter (other academic/artistic)abstract
- Optical spectroscopy is widely used for quantitative detection of small molecules in complex gas matrices. Employing a laser as a light source enables highly sensitive, selective, and accurate trace gas analysis in exhaled breath without the need for frequent calibration. Many volatile species with direct physiological relevance, especially small molecules such as CO2, CO, NO, CH4, NH3, HCN, C2H4, and their isotopoloques, can be measured with high time resolution using compact optical analyzers. Thus, laser-based sensors are an important complement to other analytical platforms and contribute to establishing breath gas analysis in the clinical practice. This chapter introduces the basics of optical spectroscopy and describes the most relevant techniques currently used in the field, such as nondispersive, laser absorption, and photoacoustic spectroscopy. Successful applications of optical methods are presented, and the future prospects are discussed. Owing to the advent of novel light sources, such as quantum cascade lasers and optical frequency combs, spectroscopy will continue to play a significant role in breath gas analysis.
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