- Detection of nitrated and oxygenated polycyclic aromatic hydrocarbons using atmospheric pressure chemical ionization high resolution mass spectrometry
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Polycyclic aromatic hydrocarbons (PAHs) are common pollutants in the atmosphere and have long been recognized to be toxic to humans. These PAHs can be oxidized into more toxic products in both the gas and condensed (on the surface of suspended particulate matter) phases. In this work, we report fragmentation patterns observed using atmospheric pressure chemical ionization with high resolution mass spectrometry (APCI-HRMS) of PAH oxidation products. A representative group of 18 PAH derivatives containing carbonyl (oxo-PAHs), hydroxyl (hydroxy-PAHs), carboxyl (carboxy-PAHs), and/or nitro (nitro-PAHs) groups were studied. Ionization of carboxy-PAHs in negative mode yielded common fragments of [M-H]-, [M-H-CO]-, and [M-H-CO2]-. Oxo-PAHs provided common fragments of [M+H]+, [M+H-CO]+ and [M+H-2CO]+ in positive mode and [M+e-]- in negative mode. Mass spectra of aldehydes exhibited common fragments of [M+H]+, [M+H-CO]+, and [M+H-O]+ in positive mode and [M+e-]- and [M-H+O]- in negative mode. For all nitro-PAHs, [M+H]+, [M+H-O]+ and [M+3H-O2]+ ions were observed in positive mode. On the basis of the APCI-HRMS analysis of standards, eight reaction products of pyrene oxidation under heterogeneous conditions were characterized. HRMS data, specific fragments and common ions such as that of 205 m/z, characteristic for carbonyl phenanthrene, enabled the identification of the oxidation products.
- Cochran, Richard E.,Smoliakova, Irina P.,Kubátová, Alena
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- The epigenetic toxicity of pyrene and related ozonation byproducts containing an aldehyde functional group
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Gap junction intercellular communication (GJIC) was used to assess the epigenetic toxicity of pyrene, pure byproducts of pyrene ozonation, and other compounds similar in chemical structure. Byproduct mixtures collected from HPLC were also evaluated using GJIC. Of the 11 pure compounds studied, five inhibited GJIC completely. Two inhibiting compounds contained four rings and were the only compounds studied with greater than three rings. The remaining three compounds contained either two or three rings, and all three contained an aldehyde group. Toxicological evaluation and GC/MS of impure byproduct mixtures showed that two common compounds were found in inhibiting fractions. These common compounds contained both a bay region and at least one aldehyde group.
- Herner, Holly A.,Trosko, James E.,Masten, Susan J.
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p. 3576 - 3583
(2007/10/03)
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- Ring-chain tautomerism. Part 10 +. The reaction of oxocarboxylic acids with diazodiphenylmethane
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The rate coefficients for the esterification of a series of oxocarboxylic acids with diazodiphenylmethane have been determined in ethanol or 2-methoxyethanol at 30.0°C. These and the rates of reaction with model compounds have been used to estimate the equilibrium constants for ring-chain tautomerism for the oxocarboxylic acids.
- Bowden, Keith,Misic-Vukovic, Milica M.,Ranson, Richard J.
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p. 1601 - 1606
(2007/10/03)
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- Chiral Recognition in Aqueous Solution. Search for Water-Soluble Chiral Hosts with Apolar Binding Sites
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Macrocycles 1a/1b with terasubstituted biphenyl units as chiral barriers are designed as potential hosts for the optical resolution of racemic aromatic guests with anionic residues.Synthetic attempts to prepare from a planar arene, pyrene, a chiral biphen
- Rubin, Yves,Dick, Klaus,Diederich, Francois,Georgiadis, Taxiarchis M.
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p. 3270 - 3278
(2007/10/02)
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