Comparative analysis of feature annotation methods for SESI-HRMS in exhaled breath analysis.

Secondary electrospray ionization coupled to high-resolution mass spectrometry (SESI-HRMS) is a powerful method for the analysis of exhaled breath in real time. However, feature annotation is challenging due to the flow-injection nature of the technique. To evaluate alternative methods for enhancing feature annotation, a study was conducted where the exhaled breath of sixteen subjects was condensed and analyzed using dynamic headspace vacuum in-trap extraction gas chromatography-mass spectrometry (DHS-V-ITEX-GC-MS) and liquid chromatography coupled to mass spectrometry (LC-MS) using polar and reverse-phase conditions along with a data-independent MS-acquisition method based on multiple injections.

Systematic study of polymer gas sampling bags for offline analysis of exhaled breath.

Polymeric bags are a widely applied, simple, and cost-effective method for the storage and offline analysis of gaseous samples. Various materials have been used as sampling bags, all known to contain impurities and differing in their cost, durability, and storage capabilities. Herein, we present a comparative study of several well-known bag materials, Tedlar (PVF), Kynar (PVDF), Teflon (PTFE), and Nalophan (PET), as well as a new material, ethylene vinyl copolymer (EVOH), commonly used for storing food.

Internal Standard Addition System for Online Breath Analysis.

Breath analysis with secondary electrospray ionization (SESI) coupled to mass spectrometry (MS) is a sensitive method for breath metabolomics. To enable quantitative assessments using SESI-MS, a system was developed to introduce controlled amounts of gases into breath samples and carry out standard addition experiments. The system combines gas standard generation through controlled evaporation, humidification, breath dilution, and standard injection with the help of mass-flow controllers.

Alternative electrolyte solutions for untargeted breath metabolomics using secondary-electrospray ionization high-resolution mass spectrometry.

Rationale: Secondary-electrospray ionization (SESI) coupled with high-resolution mass spectrometry is a powerful tool for the discovery of biomarkers in exhaled breath. A primary electrospray consisting of aqueous formic acid (FA) is currently used to charge the volatile organic compounds in breath. To investigate whether alternate electrospray compositions could enable different metabolite coverage and sensitivities, the electrospray dopants NaI and AgNO were tested.

Exhalomics as a noninvasive method for assessing rumen fermentation in dairy cows: Can exhaled-breath metabolomics replace rumen sampling?

Previously, we used secondary electrospray ionization-mass spectrometry (SESI-MS) to investigate the diurnal patterns and signal intensities of exhaled (EX) volatile fatty acids (VFA) of dairy cows. The current study aimed to validate the potential of an exhalomics approach for evaluating rumen fermentation. The experiment was conducted in a switchback design, with 3 periods of 9 d each, including 7 d for adaptation and 2 d for sampling.

Food and lifestyle impact on breath VOCs using portable mass spectrometer-pilot study across European countries.

In the modern world, many people are changing old dietary and lifestyle habits to improve the quality of their living-to treat or just prevent possible diseases. The main goal of this pilot study was to assess the food and lifestyle impact on exhaled breath volatile organic compounds (VOCs) in various population groups. It was done by employing a recently validated portable membrane-inlet mass spectrometer-MIMS.

Exhaled volatile fatty acids, ruminal methane emission, and their diurnal patterns in lactating dairy cows.

To date, the commonly used methods to assess rumen fermentation are invasive. Exhaled breath contains hundreds of volatile organic compounds (VOC) that can reflect animal physiological processes. In the present study, for the first time, we aimed to use a noninvasive metabolomics approach based on high-resolution mass spectrometry to identify rumen fermentation parameters in dairy cows.

Analysis of volatile short-chain fatty acids in the gas phase using secondary electrospray ionization coupled to mass spectrometry.

Quantification of metabolites present within exhaled breath is a major challenge for on-line breath analysis. It is also important for gauging the analytical performance, accuracy, reproducibility, reliability, and stability of the measuring technology. Short-chain fatty acids (SCFAs) are of high interest for nutrition and health.

How Soft Is Secondary Electrospray Ionization?

Secondary electrospray ionization (SESI) mass spectrometry (MS) is a direct infusion technique often used for untargeted metabolomics, e.g., for online breath analysis.

Breath response following a nutritional challenge monitored by secondary electrospray ionization high-resolution mass spectrometry.

On-line breath analysis using secondary electrospray ionization coupled to high-resolution mass spectrometry (SESI-HRMS) is a sensitive method for biomarker discovery. The strengths of this technology have already been demonstrated in the clinical environment. For the first time, this study demonstrates the application of SESI-HRMS in the field of nutritional science using a standardized nutritional intervention, consisting of a high-energy shake (950 kcal, 8% protein, 35% sugar and 57% fat).

Membrane inlet mass spectrometry method for food intake impact assessment on specific volatile organic compounds in exhaled breath.

This research work describes the development of a novel bioanalytical method for the assessment of food impact on selected exhaled breath volatile organic compounds (VOCs) using a fast and portable screening VOC prototype sensor based on membrane inlet mass spectrometry (MIMS). Method and sensor prototype functionality was verified by obtaining good response times, linearity in the examined concentration ranges, and sensitivity and repeatability for several breath VOCs-acetone, ethanol, n-pentane, and isoprene. A new VOC sensor prototype was also proven to be sensitive enough for selected breath VOC quantification with limits of detection at low part per billion (ppb) levels-5 ppb for n-pentane, 10 ppb for acetone and ethanol, and 25 ppb for isoprene.

Analysis of volatile emissions from grape berries infected with Aspergillus carbonarius using hyphenated and portable mass spectrometry.

Mycotoxins represent a serious risk for human and animal health. Οchratoxin A (OTA) is a carcinogenic mycotoxin produced by A. carbonarius that constitutes a severe problem for viticulture.

Real-Time Detection of Aerosol Metals Using Online Extractive Electrospray Ionization Mass Spectrometry.

Metal emissions are of major environmental and practical concern because of their highly toxic effects on human health and ecosystems. Current technologies available in the market for their detection are typically limited by a time resolution of 1 h or longer (e.g.

Analysis of Essential Fragrant Oils Using a Portable Mass Spectrometer.

A portable mass spectrometer was coupled to a direct inlet membrane (DIM) probe and applied to the direct analysis of active fragrant compounds (3-methylbutyl acetate, 2-methyl-3-furanthiol, methyl butanoate, and ethyl methyl sulfide) in real time. These fragrant active compounds are commonly used in the formulation of flavours and fragrances. Results obtained show that the portable mass spectrometer with a direct membrane inlet can be used to detect traces of the active fragrant compounds in complex mixtures such as essential fragrant oils and this represents a novel in-situ analysis methodology.

Volatolomics: A broad area of experimentation.

Chemical analysis (detection and monitoring) of compounds associated with the metabolic activities of an organism is at the cutting edge of science. Volatile metabolomics (volatolomics) are applied in a broad range of applications including: biomedical research (e.g.

An optimised quadrupole mass spectrometer with a dual filter analyser for in-field chemical sniffing of volatile organic compounds.

We report a novel portable 17 kg system based on a quadrupole mass spectrometer (QMS) with an electronic power consumption of 24 W. The system can be used for the in-field identification of gases and volatile/semivolatile organic compounds (VOCs/SVOCs). The mass analyser is a custom-made quadrupole mass filter with a Brubaker pre-filter that gives a mass range of m/z 1-500.

A Chemical Alphabet for Macromolecular Communications.

Molecular communications in macroscale environments is an emerging field of study driven by the intriguing prospect of sending coded information over olfactory networks. For the first time, this article reports two signal modulation techniques (on-off keying-OOK, and concentration shift keying-CSK) which have been used to encode and transmit digital information using odors over distances of 1-4 m. Molecular transmission of digital data was experimentally investigated for the letter "r" with a binary value of 01110010 (ASCII) for a gas stream network channel (up to 4 m) using mass spectrometry (MS) as the main detection-decoding system.

Advances in chemical sensing technologies for VOCs in breath for security/threat assessment, illicit drug detection, and human trafficking activity.

On-site chemical sensing of compounds associated with security and terrorist attacks is of worldwide interest. Other related bio-monitoring topics include identification of individuals posing a threat from illicit drugs, explosive manufacturing, as well as searching for victims of human trafficking and collapsed buildings. The current status of field analytical technologies is directed towards the detection and identification of vapours and volatile organic compounds (VOCs).

Molecular Communication over Gas Stream Channels using Portable Mass Spectrometry.

The synthetic generation/coding and transmission of olfactory information over a gas stream or an odor network is a new and unexplored field. Application areas vary from the entertainment or advertisement industry to security and telemedicine. However, current technological limitations frustrate the accurate reproduction of decoded and transmitted olfactory data.

Chemical Sniffing Instrumentation for Security Applications.

Border control for homeland security faces major challenges worldwide due to chemical threats from national and/or international terrorism as well as organized crime. A wide range of technologies and systems with threat detection and monitoring capabilities has emerged to identify the chemical footprint associated with these illegal activities. This review paper investigates artificial sniffing technologies used as chemical sensors for point-of-use chemical analysis, especially during border security applications.

Membrane inlet mass spectrometry for homeland security and forensic applications.

A man-portable membrane inlet mass spectrometer has been built and tested to detect and monitor characteristic odors emitted from the human body and also from threat substances. In each case, a heated membrane sampling probe was used. During human scent monitoring experiments, data were obtained for inorganic gases and volatile organic compounds emitted from human breath and sweat in a confined space.

Dynamic vapor generator that simulates transient odor emissions of victims entrapped in the voids of collapsed buildings.

The design, development, and validation of a dynamic vapor generator are presented. The generator simulates human scent (odor) emissions from trapped victims in the voids of collapsed buildings. The validation of the device was carried out using a reference detector: a quadrupole mass spectrometer equipped with a pulsed sampling (PS-MS) system.

Monitoring of human chemical signatures using membrane inlet mass spectrometry.

This work is an attempt to assist border security crackdown on illegal human immigration, by providing essential results on human chemical signatures. Data was obtained using a portable quadrupole mass spectrometer coupled with a membrane probe for volunteers of both genders and under different conditions in a container simulator. During experiments, participants were asked to follow various protocols while volatile organic compounds emitted from their breath, sweat, skin, and other biological excretes were continuously being monitored.