| abstract |
The measuring device described is based on the NDIR method. Pulsed infrared light passes through in parallel in two beam paths (3,4), first one with ¹³CO₂ and one with ¹²CO₂ (6,7) and subsequently also in parallel two cuvettes (8,9), which are filled with the gas sample to be analyzed. The two latter cuvettes (8, 9 together with a condenser microphone (15) serving as a pressure transducer form an optopneumatic receiver (17). By regulating the pressure in one of the two first cuvettes (6), the minimum of the pressure transducer signal is sought and obtained with one The easy-to-implement device allows an inexpensive ¹³CO₂ breath test to be carried out |