Comparisoin between mass spectrometry and Haldane technique in analysing O2 and CO2 concentrations in air gas...

We have evaluated a mass spectrometer for use as a gas analyser in air gas mixtures. Simultaneous determinations of O2 and CO2 concentrations with both the mass spectrometer and the Haldane technique were done in ninety-nine different samples of expired air from ordinary laboratory experiments. The mean differences (+/- SD) between the two techniques for O2 and CO2 concentrations were 0.003% (+/- 0.049%), and 0.001% (+/- 0.045%) absolute values, respectively, (P greater than 0.05 for both), r values being 0.996 for O2 and 0.994 for CO2. There was a drift in the apparatus, which decreased with operating time. Proper calibration is necessary for accurate readings. A cost-benefit balance is made.