Hydroxylation of aromatic hydrocarbons in mass spectrometer ion sources under atmospheric pressure ionization and chemical ionization conditions

Mahle, Nels H.; Cooks, R. Graham; Korzeniowski, R. W.

doi:10.1021/ac00264a017

Cited by 16 publications

(12 citation statements)

References 40 publications

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“…Compounds such as 1,4‐cyclohexadiene, 4‐methyl‐1,3‐dioxolane, and pyridine were also subjected to LTP, and the corresponding spectra are shown in Figure 2 D–F. The major ionic species are the molecular ions ( M .+ , [ M −H] + , [ M +H] + ), similar to what has been reported for glow‐discharge ionization10 and atmospheric pressure chemical ionization (APCI) 11…”

Section: Methodssupporting

confidence: 71%

Birch Reduction of Benzene in a Low‐Temperature Plasma

Xia

Zhu

et al. 2009

Angewandte Chemie

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Selektive und spezifische Dihydrierungen von Benzol und anderen Arenen wurden in einem Tieftemperatur‐Heliumplasma beobachtet. Im vorgeschlagenen Mechanismus werden die Benzolmoleküle an der Entladungsoberfläche adsorbiert. Dort fangen sie in einer Birch‐Reduktion zunächst adsorbierte niederenergetische Elektronen ein und werden anschließend protoniert (siehe Bild). Die Reduktionsreaktion wird von Oxidationsprozessen in der Gasphase begleitet.

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Section: Methodssupporting

confidence: 71%

Birch Reduction of Benzene in a Low‐Temperature Plasma

Xia

Zhu

et al. 2009

Angewandte Chemie

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“…Although the presence of oxygenated aromatic hydrocarbons in API is known since 1983, when Mahle et al observed hydroxylated benzene upon APCI of benzene [49], no evidence for neutral radical chemistry was discussed until 2005, when Frey et al investigated oxidized proteins observed upon APCI. They tentatively explained their observations in analogy to the atmospheric degradation of organic compounds with OH radicals [50].…”

Section: Discussionmentioning

confidence: 99%

Evidence of neutral radical induced analyte ion transformations in APPI and Near-VUV APLI

Kersten

Funcke

Lorenz

et al. 2009

J. Am. Soc. Mass Spectrom.

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We report on the reactions of neutral radical species [OH, Cl, O(3P), H], generated in a typical atmospheric pressure ionization (API) source upon irradiation of the sample gases with either 193 nm laser radiation or 124 nm VUV light, the latter commonly used in atmospheric pressure photoionization (APPI). The present investigations focus on the polycyclic aromatic hydrocarbon pyrene as representative of the aromatic compound class. Experimental results are supported by computational methods: simple kinetic models are used to estimate the temporal evolution of the concentrations of reactants, intermediates, and final products, whereas density functional theory (DFT) energy calculations are carried out to further elucidate the proposed reaction pathways. The neutral radicals are generated upon photolysis of background water and oxygen always present in appreciable mixing ratios in typical API sources. Substantial amounts of oxygenated analyte product ions are observed using both techniques. In contrast, upon atmospheric pressure laser ionization (APLI) with 248 nm radiation, oxygenated products are virtually absent. In addition, kinetic data evaluation yielded a bimolecular rate constant of k = (1.9 +/- 0.9) x 10(-9) cm3 molecule(-1) s(-1) for the reaction of the pyrene radical cation with OH radicals.

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“…The major products include tion [10] and atmospheric pressure chemical ionization (APCI). [11] A certain degree of oxidation is also observed for these compounds, but no signal corresponding to a reduced species is detected. Molecules with a variety of functional types were also subjected to LTP and their product ions were analyzed by mass spectrometry (Table S1 in the Supporting Information).…”

mentioning

confidence: 96%