Hybrid Analytical Platform Based on Field-Asymmetric Ion Mobility Spectrometry, Infrared Sensing, and Luminescence-Based Oxygen Sensing for Exhaled Breath Analysis

Abstract

The reliable online analysis of volatile compounds in exhaled breath remains a challenge, as a plethora of molecules occur in different concentration ranges (i.e., ppt to %) and need to be detected against an extremely complex background matrix. Although this complexity is commonly addressed by hyphenating a specific analytical technique with appropriate preconcentration and/or preseparation strategies prior to detection, we herein propose the combination of three different detector types based on truly orthogonal measurement principles as an alternative solution: Field-asymmetric ion mobility spectrometry (FAIMS), Fourier-transform infrared (FTIR) spectroscopy-based sensors utilizing substrate-integrated hollow waveguides (iHWG), and luminescence sensing (LS). By carefully aligning the experimental needs and measurement protocols of all three methods, they were successfully integrated into a single compact analytical platform suitable for online measurements. The analytical performance of this prototype system was tested via artificial breath samples containing nitrogen (N2), oxygen (O2), carbon dioxide (CO2), and acetone as a model volatile organic compound (VOC) commonly present in breath. All three target analytes could be detected within their respectively breath-relevant concentration range, i.e., CO2 and O2 at 3-5 % and at ~19.6 %, respectively, while acetone could be detected with LOQs as low as 165-405 ppt. Orthogonality of the three methods operating in concert was clearly proven, which is essential to cover a possibly wide range of detectable analytes. Finally, the remaining challenges toward the implementation of the developed hybrid FAIMS-FTIR-LS system for exhaled breath analysis for metabolic studies in small animal intensive care units are discussed.

Optimization of a breath analysis methodology to potentially diagnose transplanted kidney rejection

“…Hippocrates (460-370 BCE) rst described it in his "treatise on respiratory aromas and diseases". Over the past thirty years, scientists have identi ed thousands of different breath organic compounds, employing emerging analytical techniques, including proton transfer reaction mass spectrometry (PTR-MS) [11][12][13][14], proton reaction transfer time-of-ight mass spectrometry [15][16][17][18], selected ion stream tube mass spectrometry (SIFT-MS) [19][20][21][22][23], laser spectroscopy [24,25], ion mobility spectrometry [26][27][28] sensor array [29], and electronic nose technology [30][31][32][33], even if the gold standard for detecting respiratory biomarkers is a combination of gas chromatography and mass spectrometry (GC-MS) [3,[34][35][36]. However, independently from the diagnostic technique employed, several studies have demonstrated that breath analysis may be a promising strategy for detection and follow-up of kidney disease.…”

Quantitative Analysis and Discrimination of Partially Fermented Teas from Different Origins Using Visible/Near-Infrared Spectroscopy Coupled with Chemometrics

“…Therefore, a rapid, efficient, repeatable, objective, and economical nondestructive inspection method is needed for origin discrimination of tea. For example, gas-phase infrared spectroscopy, one of the artificial olfaction sensing systems, has the potential to be helpful as a screening method for the quality control of tea because of its increased sensitivity, resolution, high signal-to-noise ratio, multiple-component analysis, and rapid measurement capabilities [ 13 , 14 ].…”