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6. Effects of high relative humidity and dry purging on VOCs obtained during breath sampling on common sorbent tubesMaxim Wilkinson, Iain R White, Roy Goodacre, Tamara Nijsen, Stephen Fowler, 2020, izvirni znanstveni članek Opis: Offline breath analysis by thermal desorption gas chromatography mass spectrometry (TD-GC-MS) requires the use of sorbent traps to concentrate and store volatile compounds. The selection of which sorbent to use and best practices for managing high relative humidity are important considerations to allow for reproducible, untargeted, biomarker discovery in water saturated breath samples. This work aims to assess three commonly used sorbent materials for their use in breath volatile sampling and determine how the high relative humidity inherent in such samples effects the capture of volatile compounds of interest. TenaxGR, TenaxTA/Carbograph1TD and TenaxTA/Carbograph5TD tubes were selected as they are the most commonly used sorbents in the breath sampling literature. The recovery of 29 compounds in a standard mix loaded using high humidity gas was tested for each sorbent and compared to loading in dry gas. Water retention and dry purge rates were determined for each sorbent for 500 ml and 1000 ml breath collections. Finally, breath samples were collected simultaneously on to each sorbent type using the ReCIVA and analysed by TD-GC-MS. All three sorbents exhibited acceptable reproducibility when loaded with the standard mix in dry gas (RSD < 10%). Loading the standard mix in humid gas led to reduced recovery of compounds based on their chemical properties. Dry purging performance for each sorbent material was assessed and was shown to be 1.14, 1.13 and 0.89 mg H2O min−1 for TenaxGR, TenaxTA/Carbograph1TD and TenaxTA/Carbograph5TD respectively when flushed with 50 ml min−1 of N2. A comparison of breath profiles on different sorbents showed differences in background artefacts (sulfur dioxide, cyclopenten-1-one and 3-nonene) and endogenous breath compounds (2-methyl-furan and furfural). This work demonstrates that high relative humidity during sampling reduces the ability of sorbent tubes to capture volatile compounds and could impact method detection limits during breath sampling. Sufficient water to impair accurate analysis was retained on all tubes. Minimal differences were observed between sorbent materials when used to sample breath, however, suggestions are provided for sorbent selection for future studies.
Ključne besede: VOCs, Breath sampling, ReCIVA
Objavljeno: 27.07.2020; Ogledov: 110; Prenosov: 5
 Polno besedilo (1,18 MB) |
7. Large-scale anisotropies above 0.03 EeV measured by the Pierre Auger ObservatoryLukas Zehrer, Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Marta Trini, Samo Stanič, Gašper Kukec Mezek, Andrej Filipčič, Esteban Roulet, 2019, objavljeni znanstveni prispevek na konferenci Ključne besede: ultra-high energy cosmic rays (UHECRs), Pierre Auger Observatory, UHECR arrival directions, large-scale anisotropies
Objavljeno: 24.07.2020; Ogledov: 69; Prenosov: 3
Polno besedilo (894,55 KB) |
8. A Large Radio Detector at the Pierre Auger Observatory – Measuring the Properties of Cosmic Rays up to the Highest EnergiesLukas Zehrer, Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Marta Trini, Samo Stanič, Gašper Kukec Mezek, Andrej Filipčič, Bjarni Pont, 2019, objavljeni znanstveni prispevek na konferenci Ključne besede: ultra-high energy cosmic rays (UHECRs), Pierre Auger Observatory, UHECR Radio Detection, Auger Engineering Radio Array (AERA), AugerPrime Upgrade Radio Detectors
Objavljeno: 24.07.2020; Ogledov: 72; Prenosov: 2
Polno besedilo (1,94 MB) |
9. Measurement of the fluctuations in the number of muons in inclined air showers with the Pierre Auger ObservatoryLukas Zehrer, Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Marta Trini, Samo Stanič, Gašper Kukec Mezek, Andrej Filipčič, Felix Riehn, 2019, objavljeni znanstveni prispevek na konferenci Ključne besede: ultra-high energy cosmic rays, Pierre Auger Observatory, inclined air showers, muon number fluctuations
Objavljeno: 24.07.2020; Ogledov: 60; Prenosov: 2
Polno besedilo (630,96 KB) |
10. Measurement of the spectrum of cosmic rays above 10^16.5 eV with Cherenkov–dominated events at the Pierre Auger ObservatoryLukas Zehrer, Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Marta Trini, Samo Stanič, Gašper Kukec Mezek, Andrej Filipčič, Vladimír Novotný, 2019, objavljeni znanstveni prispevek na konferenci Ključne besede: ultra-high energy cosmic rays (UHECRs), Pierre Auger Observatory, UHECR energy spectrum, Cherenkov–dominated UHECR events
Objavljeno: 24.07.2020; Ogledov: 59; Prenosov: 2
Polno besedilo (377,09 KB) |
