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. Thus, the obtained results would also represent the additional confirmation for the employment of the new instrument in the breath analysis. The pilot study involved 151 participants across Europe, including people with overweight, obesity, type 2 diabetes mellitus, cardiovascular disease, people with poor-quality diet and professional athletes. Exhaled breath acetone, ethanol, isoprene, and n-pentane levels were determined in samples before the meal, and 120 min after the meal. Obtained basal ppbvvalues were mainly in accordance with previously reported, which confirms that MIMS instrument can be used in the breath analysis. Combining the quantified levels along with the information about the participants' lifestyle habits collected via questionnaire, an assessment of the food and lifestyle impact was obtained. Notable alteration in examined VOC levels upon meal consumption was detected in more than 70% of all participants, with exception for isoprene, which was affected in about half of participants. Lifestyle parameters impact was examined using statistical analysis of variance (ANOVA) on ranks test. Statistically significant differences in basal breath VOC levels were observed among all examined population groups. Also, n-pentane and ethanol levels significantly differed in people of different ages, as well as acetone levels in people with different physical activity habits. These findings are promising for further, more focused research using MIMS technique in breath analysis.

Users' Perspective on the AI-Based Smartphone PROTEIN App for Personalized Nutrition and Healthy Living: A Modified Technology Acceptance Model (mTAM) Approach.

The ubiquitous nature of smartphone ownership, its broad application and usage, along with its interactive delivery of timely feedback are appealing for health-related behavior change interventions via mobile apps. However, users' perspectives about such apps are vital in better bridging the gap between their design intention and effective practical usage. In this vein, a modified technology acceptance model (mTAM) is proposed here, to explain the relationship between users' perspectives when using an AI-based smartphone app for personalized nutrition and healthy living, namely, PROTEIN, and the mTAM constructs toward behavior change in their nutrition and physical activity habits. In particular, online survey data from 85 users of the PROTEIN app within a period of 2 months were subjected to confirmatory factor analysis (CFA) and regression analysis (RA) to reveal the relationship of the mTAM constructs, i.e., perceived usefulness (PU), perceived ease of use (PEoU), perceived novelty (PN), perceived personalization (PP), usage attitude (UA), and usage intention (UI) with the users' behavior change (BC), as expressed via the acceptance/rejection of six related hypotheses (H1-H6), respectively. The resulted CFA-related parameters, i.e., factor loading (FL) with the related p-value, average variance extracted (AVE), and composite reliability (CR), along with the RA results, have shown that all hypotheses H1-H6 can be accepted (p < 0.001). In particular, it was found that, in all cases, FL > 0.5, CR > 0.7, AVE > 0.5, indicating that the items/constructs within the mTAM framework have good convergent validity. Moreover, the adjusted coefficient of determination (R 2) was found within the range of 0.224-0.732, justifying the positive effect of PU, PEoU, PN, and PP on the UA, that in turn positively affects the UI, leading to the BC. Additionally, using a hierarchical RA, a significant change in the prediction of BC from UA when the UI is used as a mediating variable was identified. The explored mTAM framework provides the means for explaining the role of each construct in the functionality of the PROTEIN app as a supportive tool for the users to improve their healthy living by adopting behavior change in their dietary and physical activity habits. The findings herein offer insights and references for formulating new strategies and policies to improve the collaboration among app designers, developers, behavior scientists, nutritionists, physical activity/exercise physiology experts, and marketing experts for app design/development toward behavior change.

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. Food impact assessment was accomplished by tracking the levels of acetone, ethanol, n-pentane, and isoprene in exhaled breath samples collected from 50 healthy participants before the meal and 60 min and 120 min after the meal. For acetone, isoprene, and n-pentane, a larger impact was noticed 120 min after the meal, while for ethanol, it was after 60 min. Obtained VOC levels were in the expected concentration ranges. Mean values at all time points were ~ 500-900 ppb for acetone and ~ 400-600 ppb for ethanol. Most of the results for n-pentane were below 5 ppb, but the mean value for those which were detected was ~ 30 ppb. Along with samples, data about participants' lifestyle were collected via a short questionnaire, which were compared against obtained VOC levels in order to reveal some significant correlations between habits of participants and their breath VOC levels. Portable MS: monitoring of food impact on the levels of selected VOCs from exhaled breath.

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. It is an upgrade of the previous m/z 1-200 range triple filter analyser system. Analyser design was optimized using 3D numerical simulations as a performance trade-off between single and triple filter designs while maintaining high sensitivity and ease of integration. This also required enhanced design of the electronic control unit (ECU) compared to the previous triple filter ECU designs with lower power consumption, size, weight and cost of the overall system. Another major ECU improvement includes high stability of DC voltage control and ultra-low RF drift, which is important for in-field applications that require stable mass peaks for reliable quantitative analysis and continuous monitoring. Experimental results are presented for the perfluorotributylamine (PFTBA) calibrant and acetone to assess the functionality of the instrument. Performance comparison between the dual and triple filter quadrupole analysers has also been done. Mass spectra are given for methyl benzoate (cocaine simulant), piperidine (phencyclidine simulant), cyclohexanone (C4 simulant) and 2-nitrotoluene (TNT simulant) to assess potential capability for the identification of threat compounds. All spectral results show good correlation with the NIST library mass spectra with unit resolution obtained for spectral peaks within a m/z 1-400 mass range.

Performance assessment of a portable mass spectrometer using a linear ion trap operated in non-scanning mode.

RATIONALE: The desire for mass spectrometer portability provides the motivation for simpler, lighter electronics to deliver switched potentials applied to the electrodes of the linear ion trap operated in non-scanning mode. Using a novel method of modelling and theoretical analysis, we simulate the mass analyser performance under these unfavourable operating conditions. METHODS: The electrical fields are simulated using the Charge Particle Optics software which employs the boundary element method. The ion trajectories are computed from the ion cage of the EI source to the interior of the trap where the ions are confined. The spatial/temporal ion distributions during injection are calculated from the individual ion trajectories computed with constant time-steps. Due to geometric non-linearities, ßy = 0 lines close to the apex of the stability diagram have been computed for different initial positions with zero initial velocities in order to define the acceptable maximum axial extension. RESULTS: The DC potential well depth has been estimated at about 15 eV from the axial velocity distribution, and the minimum time of ion injection at 120 µs from the temporal ion distribution. To ensure a mass separation of one unit and the confinement of the whole of the injected ions, buffer gas cooling is necessary to reduce the trajectory excursion amplitudes to 0.1 and 15 mm in the radial and axial directions, respectively. CONCLUSIONS: The portable mass spectrometer is predicted to achieve a mass resolution of better than one mass unit providing that helium buffer gas is used. An additional cooling sequence has to be added prior to moving the operating point toward the apex. Copyright © 2016 John Wiley & Sons, Ltd.

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. This article presents an overview of (a) the existing available technologies reported in the scientific literature for threat screening, (b) commercially available, portable (hand-held and stand-off) chemical detection systems, and (c) their underlying functional and operational principles. Emphasis is given to technologies that have been developed for in-field security operations, but laboratory developed techniques are also summarized as emerging technologies. The chemical analytes of interest in this review are (a) volatile organic compounds (VOCs) associated with security applications (e.g., illegal, hazardous, and terrorist events), (b) chemical "signatures" associated with human presence, and

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. Volatile emissions were detected from the human body at low ppb concentrations. Experiments with compounds associated with narcotics, explosives, and chemical warfare agents were conducted for a range of membrane types. Test compounds included methyl benzoate (odor signature of cocaine), piperidine (precursor in clandestine phencyclidine manufacturing processes), 2-nitrotoluene (breakdown product of TNT), cyclohexanone (volatile signature of plastic explosives), dimethyl methylphosphonate (used in sarin and soman nerve agent production), and 2-chloroethyl ethyl sulfide (simulant compound for sulfur mustard gas). Gas phase calibration experiments were performed allowing sub-ppb LOD to be established. The results showed excellent linearity versus concentration and rapid membrane response times.

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. Experimental setups using different membrane materials (both hydrophilic and hydrophobic) including heating of the sampling probe and sampling flow rates were examined. From our measurements, significant information was obtained for NH3, CO2, water, and volatile organic compounds levels, illustrating a human chemical profile and indicating human presence in a confined space.

Oil-in-water monitoring using membrane inlet mass spectrometry.

A membrane inlet mass spectrometry (MIMS) system has been used for detection and analysis of two types of North Sea crude oil. The system was installed on-field on the Flotta Oil Terminal (Orkney, UK). It consisted of a quadrupole mass spectrometer (QMS) connected to the capillary probe with a silicone-based membrane. The produced mass spectra and calibration plots from the MIMS instrument showed the capability to measure levels of individual hydrocarbons within crude oil in seawater. The generated mass spectra from the field tests also showed the ability to distinguish between different types of oil and to determine concentrations of toxic hydrocarbons in oil (e.g., benzene, toluene, and xylene (BTX)). The performance of the instrument at different temperatures of seawater and oil droplet sizes was also investigated. The results showed that the QMS-based MIMS system has a potential to complement existing oil-in-water (OiW) monitors by being able to detect different oil types and specific hydrocarbon concentrations with high accuracy, which are currently not supported in commercially available OiW monitors.

Effect of an axial magnetic field on the performance of a quadrupole mass spectrometer.

We consider the case of a quadrupole mass spectrometer (QMS) in which a static magnetic field is applied axially in the z-direction along the length of the mass filter. The theoretical approach assumed in the model is that the QMS contains hyperbolic rods as electrodes and that the magnetic field acts over the full length of the mass filter assembly. Initial experimental results with argon and helium for a low-resolution instrument confirm the predicted theoretical trends. The analysis also predicts for which values of operating parameters an enhancement of the instrument resolution is achieved when an axial magnetic field is applied. The model predicts instrument resolution R >3000 for a QMS with a 200 mm long mass filter via application of an axial magnetic field.

Linear ion trap fabricated using rapid manufacturing technology.

This article presents the design, construction, and test results of a linear ion trap, fabricated using digital light processing (DLP), which is a low-cost 3D layer-based manufacturing technique. The ion trap was incorporated into a portable mass spectrometer system and experimental mass spectrum was obtained for methamphetamine (m/z 182), cocaine (m/z 304), and rhodamine B (m/z 443), with a maximum observed resolution (FWHM) of 260. For rhodamine B, tandem MS capability is also demonstrated. The mass range (and resolution at higher m/z) of the instrument is also demonstrated by spectrum obtained from Ultramark (m/z 1621). The spectra obtained for the DLP trap occur at a considerably lower rf voltage than a rectilinear ion trap of similar size, which is a consequence of the hyperbolic electrode geometry and, hence, smaller r(0) in the DLP case. High mass range with low voltage operation is especially important with regard to 'in the field' applications requiring low power consumption for extended periods of operation.

Development of quadrupole mass spectrometers using rapid prototyping technology.

In this report, we present a prototype design of a quadrupole mass filter (QMF) with hyperbolic electrodes, fabricated at the University of Liverpool using digital light processing (DLP), a low-cost and lightweight 3D rapid prototyping (RP) technique. Experimental mass spectra are shown for H(2)(+), D(2)(+), and He(+) ions to provide proof of principle that the DLP mass filter is working as a mass analyzer in the low-mass range (1 to 10 amu). The performance of the DLP QMF has also been investigated for individual spectral peaks. Numerical simulations of the instrument were performed by coupling CPO and Liverpool QMS-2 programs to model both the ion source and mass filter, respectively, and the instrument is shown to perform as predicted by theory. DLP thus allows miniaturization of mass spectrometers at low cost, using hyperbolic (or other) geometries of mass analyzer electrodes that provide optimal ion manipulation and resolution for a given application. The potential of using RP fabrication techniques for developing miniature and microscale mass analyzers is also discussed.