A calibration-free ammonia breath sensor using a quantum cascade laser with WMS 2f/1f

Abstract
The amount of ammonia in exhaled breath has been linked to a variety of adverse medical conditions, including chronic kidney disease (CKD). The development of accurate, reliable breath sensors has the potential to improve medical care. Wavelength modulation spectroscopy with second harmonic normalized by the first harmonic (WMS 2f/1f) is a sensitive technique used in the development of calibration-free sensors. An ammonia gas sensor is designed and developed that uses a quantum cascade laser operating near 1,103.44 cm -1 and a multi-pass cell with an effective path length of 76.45 m. The sensor has a 7 ppbv detection limit and 5 % total uncertainty for breath measurements. The sensor was successfully used to detect ammonia in exhaled breath and compare healthy patients to patients diagnosed with CKD. © 2013 Springer-Verlag Berlin Heidelberg.

Citation
Owen, K., & Farooq, A. (2013). A calibration-free ammonia breath sensor using a quantum cascade laser with WMS 2f/1f. Applied Physics B, 116(2), 371–383. doi:10.1007/s00340-013-5701-1

Acknowledgements
We would like to acknowledge the funding provided by King Abdullah University of Science and Technology (KAUST). We would also like to thank Dr. Mohammed Ayran, Dr. Mahmoud Saleh, and the staff of the Dialysis Center at the International Medical Center in Jeddah, Saudi Arabia for their medical consultation and assistance in collecting breath samples.

Publisher
Springer Nature

Journal
Applied Physics B

DOI
10.1007/s00340-013-5701-1

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