METHOD FOR MEASURING HUMAN EXHALED AIR

A method for measuring human exhaled air by means of gas chromatography and ion mobility spectrometry, wherein an exhaled air sample enters a sample loop via a sample inlet and a multi-port valve and is subsequently conveyed by means of a carrier gas from the sample loop, via the multi-port valve through a gas chromatographic column, into an ion mobility spectrometer, and measured, which method is to provide reliable and accurate measurement results. This object is achieved in that the following steps are carried out before an exhaled air sample is introduced into the sample loop: (a) first flushing at least the gas chromatographic column, the ion mobility spectrometer and the sample loop with a flushing gas and then switching the multi-port valve in such a way that the flushing gas enters the ion mobility spectrometer and is measured; (b) then stopping the supply of flushing gas and switching the multi-port valve in such a way that ambient air flows through the gas chromatographic column into the ion mobility spectrometer and is measured; (c) then flushing at least the gas chromatographic column, the ion mobility spectrometer and the sample loop with humidified flushing gas and switching the multi-port valve in such a way that the humidified flushing gas enters the ion mobility spectrometer and is measured; and (d) subsequently stopping the supply of humidified flushing gas, conducting an exhaled air sample into the sample loop, conveying the sample, by means of the carrier gas, through the gas chromatographic column into the ion mobility spectrometer, and measuring the sample.