Towards a standard operating procedure for revealing hidden volatile organic compounds in breath: the Fourier-transform IR spectroscopy case.

ABSTRACT

Human breath contains a large amount of small volatile organic compounds (VOCs) and could therefore be used as a carrier of metabolic information for medical diagnostics. Still, in spite of several promising techniques that have been applied during the last decades to study breath content, there is a lack of breath-based diagnostic tools available for physicians. Among several promising techniques, infrared (IR) spectroscopy has already proved its potential for reliable detection of VOCs in the breath. However, due to the large dynamic range of molecular concentrations and overlapping absorption spectra of different VOCs, many low-absorption molecules stay hidden in spectroscopic measurements. To overcome this obstacle, we propose the Matryoshka method for removing masking effects and revealing the buried spectral structures in any bio-fluid in the gas phase. By exploiting both physical and digital removal steps, we demonstrate how the method reveals methane, acetone, aldehyde, and methyl butyrate in a real breath.