High-precision terahertz spectroscopy for noninvasive medicine diagnostics

AbstractIn recent years methods for exhaled breath analysis have been developing all around the world. The exhaled breath analysis could result in a powerful tool for noninvasive medicine. The work presented in this paper is concerned with gas analyzers for exhaled breath diagnostics. The analyzers are based on high-precision spectrometers of the THz frequency range, which provide high resolution, high sensitivity and detect a wide range of detectable substances. The spectrometers work on non-stationary effects (phase-switching and fast sweep of frequency). The analyzers have been successfully applied for the detection of various biomarkers (nitric oxide, acetone, ammonia, methanol, ethanol) in the breath of conditionally healthy volunteers and patients with various cancerous and noncancerous diseases.

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

Sensors ◽

10.3390/s19122653 ◽

2019 ◽

Vol 19 (12) ◽

pp. 2653

Author(s):

L. Tamina Hagemann ◽

Stefan Repp ◽

Boris Mizaikoff

Keyword(s):

Ion Mobility Spectrometry ◽

Ion Mobility ◽

Small Animal ◽

Breath Analysis ◽

Prototype System ◽

Exhaled Breath ◽

Analytical Technique ◽

Exhaled Breath Analysis ◽

Wide Range ◽

Online Measurements

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.

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Simultaneous measurement of inhaled air and exhaled breath by “Double-MCC/IMS”. A new method for breath analysis. Results of a feasibility study

ERJ Open Research ◽

10.1183/23120541.00493-2021 ◽

2021 ◽

pp. 00493-2021

Author(s):

M. Westhoff ◽

M. Friedrich ◽

J. I. Baumbach

Keyword(s):

Simultaneous Measurement ◽

High Sensitivity ◽

Breath Analysis ◽

Exhaled Breath ◽

Healthy Individuals ◽

Endogenous Production ◽

Exhaled Breath Analysis ◽

Simultaneous Registration ◽

Sampling Procedures ◽

First Time

The high sensitivity of methods, which are applied in breath analysis, entails a high risk of detecting analytes which do not derive from endogenous production. Consequentially, it appears useful to have knowledge about the composition of inhaled air and to include alveolar gradients into interpretation.The current study aimed to standardise sampling procedures in breath analysis, especially with multicapillary column ion-mobility spectrometry (MCC-IMS), by applying a simultaneous registration of inhaled air and exhaled breath.A “Double MCC-IMS” device, which for the first time allows simultaneous analysis of inhaled air and exhaled breath, was developed and tested in 18 healthy individuals. For this two BreathDiscoverys® (BDs) were coupled with each other.Measurements of inhaled air and exhaled breath in 18 healthy individuals (mean age 46±10.9 years; 9 men, 9 women) identified 35 different volatile organic compounds (VOCs) for further analysis. Not all out of these had positive alveolar gradients and could be regarded as endogenous VOCs; 16 VOCs had a positive alveolar gradient in mean, 19 VOCs a negative one. 12 VOCs were positive in more than 12 of the healthy subjects.For the first time in our understanding a method is described, which enables simultaneous measurement of inhaled air and exhaled breath. This facilitates the calculation of alveolar gradients and selection of endogenous VOCs for exhaled breath analysis. Only a part of VOCs in exhaled breath are truly endogenous VOCs. The observation of different and varying polarities of the alveolar gradients needs further analysis.

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Exhaled Breath Analysis to Predict Risk of Symptomatic Pneumonitis

Case Medical Research ◽

10.31525/ct1-nct04040244 ◽

2019 ◽

Author(s):

Keyword(s):

Breath Analysis ◽

Exhaled Breath ◽

Exhaled Breath Analysis

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A comparative study on the VOCs gas sensing properties of Zn2SnO4 nanoparticles, hollow cubes, and hollow octahedra towards exhaled breath analysis

Sensors and Actuators B Chemical ◽

10.1016/j.snb.2021.130147 ◽

2021 ◽

pp. 130147

Author(s):

Nguyen Hong Hanh ◽

Trinh Minh Ngoc ◽

Lai Van Duy ◽

Chu Manh Hung ◽

Nguyen Van Duy ◽

...

Keyword(s):

Comparative Study ◽

Gas Sensing ◽

Breath Analysis ◽

Exhaled Breath ◽

Sensing Properties ◽

Exhaled Breath Analysis ◽

Gas Sensing Properties

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Modular Breath Analyzer (MBA): Introduction of a Breath Analyzer Platform Based on an Innovative and Unique, Modular eNose Concept for Breath Diagnostics and Utilization of Calibration Transfer Methods in Breath Analysis Studies

Molecules ◽

10.3390/molecules26123776 ◽

2021 ◽

Vol 26 (12) ◽

pp. 3776

Author(s):

Carsten Jaeschke ◽

Marta Padilla ◽

Johannes Glöckler ◽

Inese Polaka ◽

Martins Leja ◽

...

Keyword(s):

Real Life ◽

Sensor Arrays ◽

Breath Analysis ◽

Exhaled Breath ◽

Calibration Transfer ◽

Early Disease Detection ◽

Exhaled Breath Analysis ◽

Breath Analyzer ◽

Analysis Experiment ◽

Before And After

Exhaled breath analysis for early disease detection may provide a convenient method for painless and non-invasive diagnosis. In this work, a novel, compact and easy-to-use breath analyzer platform with a modular sensing chamber and direct breath sampling unit is presented. The developed analyzer system comprises a compact, low volume, temperature-controlled sensing chamber in three modules that can host any type of resistive gas sensor arrays. Furthermore, in this study three modular breath analyzers are explicitly tested for reproducibility in a real-life breath analysis experiment with several calibration transfer (CT) techniques using transfer samples from the experiment. The experiment consists of classifying breath samples from 15 subjects before and after eating a specific meal using three instruments. We investigate the possibility to transfer calibration models across instruments using transfer samples from the experiment under study, since representative samples of human breath at some conditions are difficult to simulate in a laboratory. For example, exhaled breath from subjects suffering from a disease for which the biomarkers are mostly unknown. Results show that many transfer samples of all the classes under study (in our case meal/no meal) are needed, although some CT methods present reasonably good results with only one class.

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