Method for processing mass spectrometry data obtained from breath gas

A computer-implemented method for processing mass spectrometry data obtained from a breath gas, the method comprising:

• receiving a time-dependent ion profile originating from a spectrometer data sample, the spectrometer data sample having been recorded during at least one exhalation from a human or animal subject;
• the time-dependent ion profile being associated with one mass-to-charge ratio value and comprising a signal strength for said one mass-to-charge ratio value measured over a time duration;
• receiving a time-dependent breath profile, the time-dependent breath profile having been recorded during said at least one exhalation over said time duration;
• wherein the method comprises a temporal correlation step, the temporal correlation step comprising:
• determining a degree of temporal correlation between the time-dependent ion profile and the time-dependent breath profile, and
• classifying the time-dependent ion profile based on the degree of temporal correlation as either a signal of interest originating from the exhalation of the subject or a signal not correlated with the exhalation of the subject.