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Breathomics and its Application for Disease Diagnosis: A Review of Analytical Techniques and Approaches
Published in Raquel Cumeras, Xavier Correig, Volatile organic compound analysis in biomedical diagnosis applications, 2018
David J. Beale, Oliver A. H. Jones, Avinash V. Karpe, Ding Y. Oh, Iain R. White, Konstantinos A. Kouremenos, Enzo A. Palombo
SESI-MS is not widely used but both PTR-MS and SIFT-MS are popular methods of analysis in a range of areas including environmental, food and health sciences (Kumar et al., 2013; Zhan et al., 2013). In PTR-MS, a hollow cathode ion source produces H3O+ ions from high purity (> 99%) distilled water. The reagent ions enter a drift tube where the trace compounds are ionized via proton transfer before analysis with either a quadrupole or a high-resolution time-of-flight mass analyzer. A disadvantage of PTR-MS is that is can only work for target molecules with a proton affinity higher than that of water. SIFT-MS is similar to PTR-MS but uses a greater number of precursor ions for chemical ionization (H3O+, NO+, or O2+) and thus works with a wider range of exhaled metabolites. Both systems allow real-time, quantitative analysis and eliminate the need for sample preparation, pre-concentration and chromatography or other forms of separation. They do not, however, detect as many compounds as other forms of analysis such as GC and LC.
Sources and Characterization Approaches of Odour and Odour-Causing Bodily Compounds in Worn Clothing
Published in G. Thilagavathi, R. Rathinamoorthy, Odour in Textiles, 2022
Mourad Krifa, Mathilda Savocchia
McQueen et al. (2008) used headspace analysis of axillary volatile compounds released from cotton, wool, and polyester fabrics. The analytical method used in this research was proton transfer reaction-mass spectrometry (PTR-MS). The VOCs were conveyed from the sample headspace to the PTR-MS inlet through direct drawing using a heated capillary. The authors compared polyester, cotton, and wool and found results that are concordant with sensory analysis showing a higher odour intensity in polyester (McQueen et al. 2008).
V-shaped ion funnel proton transfer reaction mass spectrometry
Published in Instrumentation Science & Technology, 2019
Yujie Wang, Kexiu Dong, Yannan Chu
Proton transfer reaction mass spectrometry (PTR-MS) is a well-developed and commercially available technique for monitoring trace volatile organic compounds (VOCs). With the advantages of rapid response, high sensitivity, and soft ionization, PTR-MS is becoming an important tool applied in the environmental field, food control, medical applications, water detection, and security.[1–5] To improve the identification of VOCs, several approaches have been experimentally attempted since its inception including changes in the reduced-field E/N[1] where E is the electric field and N is the buffer gas number density, new reagent ions,[6] other mass analyzers,[7–9] and novel sampling methods.[3,10,11]
Indoor air quality and wildfire smoke impacts in the Pacific Northwest
Published in Science and Technology for the Built Environment, 2018
W. Max Kirk, Madeline Fuchs, Yibo Huangfu, Nathan Lima, Patrick O'Keeffe, Beiyu Lin, Tom Jobson, Shelley Pressley, Von Walden, Diane Cook, Brian K. Lamb
Prior to these measurements, H2 and H3 were equipped with occupancy sensors on the exterior doors and windows to indicate when each was opened or closed, as well as indoor motion and temperature sensors for assessing occupant activities. Blower door tests at 5–50 Pa were performed on H2 and H3 to determine air exchange per hour (ACH50) using standard industry practices. The so-called air exchange per hour natural (ACH50, natural), estimated via logarithmic extrapolation at 0 Pa pressure difference, can be used to characterize house tightness (see Table 1). Both outdoor and indoor trace gases and PM were monitored at each site, along with outdoor meteorological conditions. Additionally, carbon dioxide (CO2) tracer tests were conducted throughout each measurement period to determine air exchange rates. Table 2 summarizes the variables monitored and the instrumentation used for each house. Volatile organic compounds (VOCs) were measured with a Proton Transfer Reaction Mass Spectrometer (PTR-MS, Ionicon Analytik GmbH) that allows for high time resolution monitoring (∼1 min) of a range of compounds including known air toxics (Jobson and McCoskey 2010). Compounds monitored included acetonitrile (a wood smoke tracer), formaldehyde, acetaldehyde, methanol, acetone, benzene, toluene, and C2-alkylbenzenes (i.e., sum of xylenes and ethylbenzene), C3-alkylbenzenes (i.e., sum of trimethylbenzene, ethyltoluene, and propylbenzene isomers), and C4-alkylbenzenes (i.e., sum of tetramethylbenzene and its isomers).
Regenerative one-stage catalytic absorption process with cupric ions for removal of reduced sulfur compounds in polluted air
Published in Environmental Technology, 2022
Pernille Lund Kasper, Anders Feilberg
Measurements of sulfur compounds were achieved with high-sensitivity Proton-Transfer-Reaction Mass Spectrometry, PTR-MS (Ionicon Analytic, Innsbruck, Austria). The PTR-MS method is based on chemical ionization of gaseous compounds by protonated water (H3O+) in a drift tube and subsequent detection of ionized compounds in a quadropole mass spectrometer, detecting ions based on their mass-to-charge ratio (m/z). In this study, the drift tube was set to standard conditions applying a drift tube voltage of 600 V and pressure of 2.1-2.2 mbar. The temperature of the drift tube was controlled at 60. Due to humidity dependence of the hydrogen sulfide signal, this was corrected as previously described by Feilberg et al. 2010 [34] (R2> 0.99). m/z 35, m/z 49 and m/z 63 were assigned to hydrogen sulfide, methanethiol and DMS, respectively. DMDS and DMTS fragment to a higher extent. These were assigned m/z signals corresponding to the ones determined by Perraud et al. 2015 [38]. Concentrations were determined based on compound-specific rate constants as recommended by Cappellin et al. [39] and mass discrimination factors [40]. All compounds were determined with a dwell time of 200 ms. PTR-MS concentration data is presented as an average of > 10 measuring points. The detection limit of the PTR-MS was determined as 3 times the standard deviation of a blank sample using an activated charcoal filter (Supelpure HC, Sigma-Aldrich). For determination of removal efficiencies the system was monitored for >30 min for each FeEDTA and CuCl2 concentration tested. All standard deviations of measured removal efficiencies were below 3.5%. Due to low error compared to data values, error bars are omitted in the graphics.