Real-time breath volatilomics analysis by soft Ionisation Mass Spectrometry

Abstract

Background: The information contained within breath volatile organic compounds (VOCs) has the potential to identify biomarkers of disease and metabolic dysregulation. Gas chromatography-mass spectrometry (GC-MS) is the gold standard for VOC discovery however, it requires VOCs pre-concentration, long sample processing time and is not suitable for point-of-care use limiting its9 translation into the clinic. Aims: To develop a high throughput Soft Ionisation mass spectrometry (MS) method for ambient VOC analysis for deeper understanding of breath metabolites. Methods: VOCs were analysed in the breath of 3 Asthmatic and 3 healthy volunteers who exhaled directly into a SICRIT® ion source coupled to an MS analyser. MS data acquired at full scan with a mass range 50-600 m/z. and spectra from 3 exhalations of each sample were combined. Results: Some typically seen in breath VOCs were identified (Fig.1). A change in exhaled compounds among rest and exercise was seen. Most ions are in 100-250 m/z mass range. Primary breath metabolites were identified for the first time (pyruvate, urea, lactate) with prototypical secondary and tertiary metabolites described in asthma (aldehydes). Conclusions: Our findings reflect the ability of soft ionisation MS to provide high throughput, in-clinic VOC profiling for non-invasive biomarker analysis of primary, secondary, and tertiary metabolites. We are developing VOC spectral library using this novel system.