Fast quantitative analysis of natural gas by mass spectrometry using a new calibration procedure

Novel calibration method for mass spectrometers for on-line gas analysis. Set-up for the monitoring of a bacterial fermentation

“…Variations of carbon dioxide concentration in the air feed to the fermenter as supplied by a compressor, according to calibration method 4 (days 2, 3, 9 and 10 were weekends and day 7 was a national holiday) gases and one calibration mixture), instead of the one measurement in method 2. It was claimed that this method would decrease the absolute error of the calculated molar percentages from a range between 0 and 2 %M, obtained with method 1, to a range between 0 and 0.2 %M for the main components [13]. Again, we insist on the danger of a method validation based on absolute errors: a 0.2 %M absolute error on the CO 2 molar percentage, which is also what we have obtained with method 3, means a relative error of 22%, which is unacceptable when the CO 2 concentration is to be used in the calculation of fermentation parameters.…”