Abstract
Exhaled nitric oxide (NO) is one of the most promising breath markers for respiratory diseases. Its profile for exhalation and the respiratory NO production sites can provide useful information for medical disease diagnosis and therapeutic procedures. However, the high-level moisture in exhaled gas always leads to the poor selectivity and sensitivity for ion spectrometric techniques. Herein, a method based on fast non-equilibrium dilution ion mobility spectrometry (NED-IMS) was firstly proposed to directly monitor the exhaled NO profile on line. The moisture interference was eliminated by turbulently diluting the original moisture to 21% of the original with the drift gas and dilution gas. Weak enhancement was observed for humid NO response and its limit of detection at 100% relative humidity was down to 0.58 ppb. The NO concentrations at multiple exhalation flow rates were measured, while its respiratory production sites were determined by using two-compartment model (2CM) and Högman and Meriläinen algorithm (HMA). Last but not the least, the NO production sites were analyzed hourly to tentatively investigate the daily physiological process of NO. The results demonstrated the capacity of NED-IMS in the real-time analysis of exhaled NO and its production sites for clinical diagnosis and assessment.
Highlights
Many techniques including chemiluminescence analyzers, electrochemical sensors and laser-based techniques have been developed to detect exhaled NO15–17
Even though electrochemical sensors are in favor of development of portable or even hand-held devices such as the amperometric sensors developed by Aerocrine (NIOX-MINO), the device sensor needs to be replaced after 100–300 actuations resulting in the performances change over time[19]
A novel method based on fast non-equilibrium dilution ion mobility spectrometry (NED-Ion mobility spectrometry (IMS)) was proposed to capture the exhaled nitric oxide (NO) profile in real time
Summary
Many techniques including chemiluminescence analyzers, electrochemical sensors and laser-based techniques have been developed to detect exhaled NO15–17. Even though electrochemical sensors are in favor of development of portable or even hand-held devices such as the amperometric sensors developed by Aerocrine (NIOX-MINO), the device sensor needs to be replaced after 100–300 actuations resulting in the performances change over time[19] It is not suitable for multiple flow analysis, and the relatively long response time even makes them to only obtain the average FENO value for an exhalation[20,21]. We developed a method based on the dopant titrating (DT) IMS to measure exhaled NO31. A faster method based on IMS should be developed for online measurement of NO within single-breath profile. A novel method based on fast non-equilibrium dilution ion mobility spectrometry (NED-IMS) was proposed to capture the exhaled NO profile in real time. Based on 2CM and HMA, the NO production sites in respiratory system were determined, while its change during a day was studied as well
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