Measuring and correlating the concentration levels of biomarkers in exhaled breath

Abstract

In this research, a sensor system was developed to quantify and correlate the concentration levels of biomarkers present in exhaled breath. To achieve this purpose, exhaled air samples were collected from a cohort of 300 individuals, and datasets comprising concentrations of oxygen (O${}_2$), carbon dioxide (CO${}_2$), nitrous oxide (N${}_2$O), carbon monoxide (CO), and water vapor (H${}_2$O) molecules were established. The analyses of CO${}_2$ and N${}_2$O molecules were conducted utilizing our custom-built multiple-pass absorption spectroscopy (MuPAS) sensor, whereas the detection of CO and H${}_2$O molecules was carried out using our custom-built quartz-enhanced photoacoustic absorption spectroscopy (QEPAS) sensor. The oxygen molecule was examined utilizing a commercially available sensor. A novel methodology was established to correlate the concentration values of molecules and to derive the conversion equations between them. To the best of our knowledge, this study is the first to establish significant correlations between the breath molecules. Thus, it was demonstrated that the concentration values of other molecules can be determined based on the concentration value of a reference molecule. Consequently, breath analysis can be conducted in a more efficient, rapid, simple, and cost-effective manner.