Real-time monitoring of exhaled volatiles using atmospheric pressure chemical ionization on a compact mass spectrometer

AIM: Breath analyses have potential to detect early signs of disease onset. Ambient ionization allows direct combination of breath gases with MS for fast, on-line analysis. Portable MS systems would facilitate field/clinic-based breath analyses. Results & methodology: Volunteers ingested peppermint oil capsules and exhaled volatile compounds were monitored over 10 h using a compact mass spectrometer. A rise and fall in exhaled menthone was observed, peaking at 60-120 min. Real-time analysis showed a gradual rise in exhaled menthone postingestion. Sensitivity was comparable to established methods, with detection in the parts per trillion range. CONCLUSION: Breath volatiles were readily analyzed on a portable mass spectrometer through a simple inlet modification. Induced changes in exhaled profiles were detectable with high sensitivity and measurable in real-time.