Performance of an exhaled nitric oxide and carbon dioxide sensor using quantum cascade laser-based integrated cavity output spectroscopy

Abstract

Exhaled nitric oxide (NO) is an important biomarker in asthma and other respiratory disorders. The optical performance of a NOCO(2) sensor employing integrated cavity output spectroscopy (ICOS) with a quantum cascade laser operating at 5.22 microm capable of real-time NO and CO(2) measurements in a single breath cycle is reported. A NO noise-equivalent concentration of 0.4 ppb within a 1-sec integration time is achieved. The off-axis ICOS sensor performance is compared to a chemiluminescent NO analyzer and a nondispersive infrared (NDIR) CO(2) absorption capnograph. Differences between the gas analyzers are assessed by the Bland-Altman method to estimate the expected variability between the gas sensors. The off-axis ICOS sensor measurements are in good agreement with the data acquired with the two commercial gas analyzers. This work demonstrates the performance characteristics and merits of mid-infrared spectroscopy for exhaled breath analysis.

Micro gas analyzers for environmental and medical applications

“…Laser light (5.47 m) was introduced into the cell and the integrated cavity output was measured by thermoelectrically cooled IR detector. The LOD of this system was 3.6 ppbv with 4 s data acquisition, but later this was improved to 0.4 ppbv with 1 s integration [121]. The results obtained for samples of breath air using the ICOS method agreed well with data provided by NIOX.…”

Detection of disease markers in human breath with laser absorption spectroscopy

“…Using this spectral range nitric oxide has been already detected with sensitivity up to the ppb levels. The techniques as MUPASS -WMS [46][47][48], ICOS [49,50], and CALOS [51] were demonstrated. Our experiment with nitric oxide detection in the N 2 was performed using CEAS technique.…”

Spectroscopic monitoring of NO traces in plants and human breath: applications and perspectives

“…The NO x gases are best known as a by-product of vehicle pollution, but should also be considered as a feature of the rural environment, particularly following the addition of nitrate fertilizers to soils. The presence of NO x is essential for O 3 formation, so NO removal by plants could play a key role in reducing tropospheric O 3 .…”

“…However, they are bulky and expensive, have high running costs and require technical expertise in calibration, therefore limiting their use in routine patient care. A convenient alternative is offered by the electrochemical sensors, but despite their lower cost and possibility for development of portable or hand-held devices, they suffer from a lack of sensitivity (detection limit > 5 ppbv) and efficiency in NO multiple flow analysis [2][3][4].…”