Evaluation of non-targeted compound discovery capability of dehumidified alveolar exhaled breath collection by using stirbar sorptive extraction and multidimensional gas chromatography - mass spectrometry method.

In this paper, the non-targeted volatile organic compound (VOC) collection performance of a custom 75 % dehumidified alveolar breath sample collection system is evaluated. VOCs were captured using stir bar sorptive extraction (SBSE) and analysed with a thermal desorption unit paired with a multidimensional gas chromatography and mass spectrometry (TD-GC × GC-MS) instrument. A data-cleaning framework and software were developed to process the raw chromatographic data through mass spectra similarity thresholding and retention index matching. The VOC profile of the dehumidified alveolar breath was assessed by checking for 635 compounds identified in previous breath VOC analyses and 8 compounds from the peppermint initiative. The results showed the presence of 7 peppermint compounds across the volunteers' breath samples, with menthone, beta-pinene, and eucalyptol being the most consistently detected. From the screening, the database of 635 breath compounds revealed approximately 50-70 compounds with a high alveolar gradient in the volunteer's breath, predominantly consisting of hydrocarbons, ketones, alcohols, aldehydes, carboxylic acids, and nitrogen-containing compounds. Across all volunteers, monoterpenes, aromatic, and saturated hydrocarbons are consistently observed, which might be correlated with the collection process and the type of SBSE used.