DQFA-Artículos
URI permanente para esta colecciónhttps://hdl.handle.net/10953/276
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Examinando DQFA-Artículos por Materia "Atmospheric chemistry"
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Ítem Conformational Flexibility of Limonene Oxide Studied By Microwave Spectroscopy(Wiley, 2017) Loru, Donatella; Quesada-Moreno, María Mar; Avilés-Moreno, Juan Ramón; Jarman, Natasha; Huet, Thérèse R.; López-González, Juan Jesús; Sanz, María EugeniaMonoterpenoids are biogenic volatile organic compounds (BVOCs) that play a major role in atmospheric chemistry, participating in the formation of aerosols. In this work, the monoterpenoid R-(+)-limonene oxide (C10H16O) has been characterized in the gas phase by Fourier transform microwave spectroscopy in a supersonic jet. Five conformers of limonene oxide, four equatorial and one axial considering the configuration of the isopropenyl group, have been unambiguously identified from the analysis of the rotational spectrum. The observed conformers include cis and trans forms, and are stabilised by a subtle balance of hydrogen bonds, dispersive interactions and steric effects. Estimated conformational relative abundances surprisingly reveal that the axial conformer has an abundance similar to some equatorial conformers. In addition, the potential energy surface was extensively explored using density functional theory and ab initio methods.Ítem Study of Controlled Atmosphere Flexible Microtube Plasma Soft Ionization Mass Spectrometry for Detection of Volatile Organic Compounds as Potential Biomarkers in Saliva for CancerVogel, Pascal; Lazarou, Constantinos; Gazeli, Odhisea; Brandt, Sebastian; Franzke, Joachim; Moreno-González, DavidA new soft ionization device for mass spectrometry is presented using the flexible microtube plasma under controlled atmospheric conditions. The controlled atmosphere flexible microtube plasma consists of the plasma source itself connected to a gas chromatograph and a mass spectrometer using a borosilicate glass cross piece. Controlled atmosphere, for example, nitrogen and/or an oxygen mixture, is introduced to the system to create a clean ionization environment. Reproducibility issues are discussed, and solutions are presented manipulating the gas flow in the cross piece. A proof of concept is shown using a ketone mixture introduced to the mass spectrometer to optimize atmospheric conditions. Furthermore, application of the presented device for the sensitive and nonfragmenting ionization of volatile organic biomarkers relevant for cancer is carried out. Sample treatment for human saliva is described, and relevant candidate biomarkers are measured in the saliva matrix, showing a very good ionization efficiency and neglectable matrix effects with limits of detection below 80 ppt.