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Proceedings Paper

Diode laser based photoacoustic gas measuring instruments intended for medical research
Author(s): Anna Szabó; Árpád Mohácsi; Péter Novák; Daniela Aladzic; Kinga Turzó; Zoltán Rakonczay; Gábor Erős; Mihály Boros; Katalin Nagy; Gábor Szabó
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Paper Abstract

Analysis of breath and gases emanated from skin can be used for early and non-invasive diagnosis of various kinds of diseases. Two portable, compact, photoacoustic spectroscopy based trace gas sensors were developed for the detection of methane emanated from skin and ammonia emanated from oral cavity. The light sources were distributed feedback diode lasers emitting at the absorption lines of ammonia and methane, at 1.53 μm and 1.65 μm, respectively. Photoacoustic method ensures high selectivity, therefore cross-sensitivity was negligible even with large amount of water vapor and carbon dioxide in the gas sample. In case of ammonia a preconcentration unit was used to achieve lower minimum detectable concentration. Gas sample from the oral cavity was drawn through a glass tube to the preconcentration unit that chemically bonded ammonia and released it when heated. The minimum detectable concentration of ammonia was 10 ppb for 15 s gas sampling time (gas sample of 250 cm3). For methane minimum detectable concentration of 0.25 ppm was found with 12 s integration time, and it was proved to be adequate for the detection of methane emanated from human skin and from mice. Instruments measuring methane and ammonia are currently installed at two medical research laboratories at University of Szeged and tested as instruments for non-invasive clinical trials. The aim of the measurements is to determine correlations between diseases or metabolic processes and emanated gases.

Paper Details

Date Published: 8 May 2012
PDF: 7 pages
Proc. SPIE 8427, Biophotonics: Photonic Solutions for Better Health Care III, 84272J (8 May 2012); doi: 10.1117/12.921644
Show Author Affiliations
Anna Szabó, Univ. of Szeged (Hungary)
Árpád Mohácsi, Univ. of Szeged (Hungary)
Péter Novák, Univ. of Szeged (Hungary)
Daniela Aladzic, Univ. of Szeged (Hungary)
Kinga Turzó, Univ. of Szeged (Hungary)
Zoltán Rakonczay, Univ. of Szeged (Hungary)
Gábor Erős, Univ. of Szeged (Hungary)
Mihály Boros, Univ. of Szeged (Hungary)
Katalin Nagy, Univ. of Szeged (Hungary)
Gábor Szabó, Univ. of Szeged (Hungary)

Published in SPIE Proceedings Vol. 8427:
Biophotonics: Photonic Solutions for Better Health Care III
Jürgen Popp; Wolfgang Drexler; Valery V. Tuchin; Dennis L. Matthews, Editor(s)

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