Toward the quantification of the 13CO2/12CO2 ratio in exhaled mouse breath with mid-infrared hollow waveguide gas sensors

Mouse sepsis models are used to gain insight into the complex processes involved with patients suffering from glucose metabolism disorders. Measuring the expiratory release of (CO2)-C-13 after administering stable labeled C-13(6)-glucose enables assessment of the in vivo integrity and functionality of key metabolic processes. In the present study, we demonstrate that Fourier transform infrared spectroscopy operating in the mid-infrared spectral regime (2-20 mu m) combined with hollow waveguide gas sensing modules simultaneously serving as a miniaturized gas cell and as a waveguide are capable of quantitatively monitoring (CO2)-C-13 enrichment levels in low volume mouse breath samples.