Simultaneous determination of exhaled breath vapor and exhaled breath aerosol using filter-incorporated needle-trap devices: A comparison of gas-phase and droplet-bound components

Breath-composition analysis is a well-established, non-invasive method for early disease diagnosis and investigating exposure history. However, this analytical approach is hampered by the aerosol nature of breath samples and/or low concentrations of volatile organic compounds. Conventionally, two separate methods have been applied to study gas phase and breath droplets, although these approaches are expensive and time-consuming. To address this issue, for the first time a needle-trap device packed with Carboxen, which served as a sorbent for the extraction of volatile analytes from the gas-phase, and electrospun polyacrylonitrile filter, which used to capture breath aerosol was applied to breath characterization. The performance of the developed device was subsequently compared to that of Carboxen-loaded thin-film microextraction, which was employed for the first time to extract free gas-phase components. Both methods were optimized, validated, and applied for the screening of breath samples obtained from volunteers. Obtained figures of merits are as follows: limits of detection (0.01-0.2 ng mL-1), recovery (81-108%) and repeatability (<13%). To investigate the effect of droplets, breath samples acquired with and without a face mask were compared. While both methods yielded similar results for the breath samples obtained with the mask, the needle-trap device was able to provide higher concentrations of volatile organic compounds for the samples acquired without a mask due to its enhanced ability to trap droplets. Additionally, tests were also conducted to investigate breath composition after accidental exposure to chemicals. The results of these tests revealed that polar compounds tended to partition to breath droplets and were eliminated from the body more quickly, while non-polar compounds tended to remain in the gas phase and were eliminated at a slower rate.