A tunable diode laser absorption spectroscopy (TDLAS) system equipped with a IV–VI mid-IR laser operating near 5.2>mu;m was used to measure exhaled nitric oxide (eNO) and carbon dioxide (CO<sub>2</sub>) simultaneously in human breath over a single exhalation. Breath was sampled in real time, and eNO levels were measured from seven volunteers, two steroid-naive asthmatics and five nonasthmatics. Measured CO<sub>2</sub> levels were used as an internal standard to verify correct breath collection and calculate eNO values. Calculated eNO concentrations agreed well with reported values for asthmatic and nonasthmatic individuals.
© 2002 Optical Society of America
C. Roller, K. Namjou, J. Jeffers, W. Potter, P. J. McCann, and J. Grego, "Simultaneous NO and CO2 measurement in human breath with a single IV-VI mid-infrared laser," Opt. Lett. 27, 107-109 (2002)