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Aqueous Phase Photo-oxidation of Water Soluble Organic Compounds (WSOC): Kinetics, Mechanisms and Method CharacterizationAljawhary, Dana 11 July 2013 (has links)
The aqueous phase photo-oxidation of water soluble organic compounds (WSOC) extracted from α-pinene ozonolysis secondary organic aerosol (SOA) was investigated using high resolution time-of-flight chemical ionization mass spectrometry (CI-ToFMS). The results have shown that WSOC get more functionalized and fragmented as the reaction proceeds. The capabilities of three reagent ions, were assessed; specifically, (H2O)nH+ ionizes organic compounds with carbon oxidation state (OSC) ≤ 1.3, whereas CH3C(O)O- and I(H2O)n- ionize highly oxygenated organics with OSC up to 4, with I(H2O)n- showing more selectivity.
The aqueous phase OH oxidation of cis-pinonic acid and tricarballylic acid (a surrogate for 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA), recognized as a tracer of α-pinene SOA) were also studied. The respective rate constants at 301 K were measured to be 3.4(±0.5)×10^9 M^-1s^-1 at pH=2 and 3.1(±0.3)×10^8 M^-1s^-1 at pH=4.6. This work also illustrates possible aqueous phase mechanism for MBTCA formation from cis-pinonic oxidation.
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Aqueous Phase Photo-oxidation of Water Soluble Organic Compounds (WSOC): Kinetics, Mechanisms and Method CharacterizationAljawhary, Dana 11 July 2013 (has links)
The aqueous phase photo-oxidation of water soluble organic compounds (WSOC) extracted from α-pinene ozonolysis secondary organic aerosol (SOA) was investigated using high resolution time-of-flight chemical ionization mass spectrometry (CI-ToFMS). The results have shown that WSOC get more functionalized and fragmented as the reaction proceeds. The capabilities of three reagent ions, were assessed; specifically, (H2O)nH+ ionizes organic compounds with carbon oxidation state (OSC) ≤ 1.3, whereas CH3C(O)O- and I(H2O)n- ionize highly oxygenated organics with OSC up to 4, with I(H2O)n- showing more selectivity.
The aqueous phase OH oxidation of cis-pinonic acid and tricarballylic acid (a surrogate for 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA), recognized as a tracer of α-pinene SOA) were also studied. The respective rate constants at 301 K were measured to be 3.4(±0.5)×10^9 M^-1s^-1 at pH=2 and 3.1(±0.3)×10^8 M^-1s^-1 at pH=4.6. This work also illustrates possible aqueous phase mechanism for MBTCA formation from cis-pinonic oxidation.
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