A Sensitive Isotope Selective Nondispersive Infrared Spectrometer for 13CO2 and 12CO2 Concentration Measurements in Breath Samples |
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| Authors: | M Haisch P Hering W Fuss W Fabinski |
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| Institution: | 1. Institut für Lasermedizin der Universit?t , Düsseldorf;2. Max-Planck-Institut für Quantenoptik , Garching;3. Max-Planck-Institut für Quantenoptik , Garching;4. Hartmann &5. Braun AG , Frankfurt |
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| Abstract: | We present a nondispersive infrared spectrometer (NDIRS) for the measurement of the 13CO2/12CO2-ratio in breath samples. A commercial NDIR spectrometer for CO2 concentration measurements in industrial process control was modified using two separate optical channels for the 13CO2 and 12CO2 detection. Cross interference due to overlapping absorption lines of both isotopic gases was successfully eliminated. The sensitivity of this device is ± 0.4‰ of the 13CO2/12CO2-ratio in a range of 2.5 to 5% of total CO2. This is sufficient for biomedical applications. Our spectrometer is small in size, cheap and simple to operate and thus a true alternative to isotope ratio mass spectrometers (IRMS). Several biomedical applications with breath samples were demonstrated and were compared in very good agreement with IRMS. |
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| Keywords: | Breath test carbon 13 13CO2 12CO2 isotope selective nondispersive infrared spectroscopy |
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