Kinetic study of OH radical reaction with n -heptane and n -hexane at 240-340K using the relative rate/discharge flow/mass spectrometry (RR/DF/MS) technique

2011 ◽  
Vol 43 (9) ◽  
pp. 489-497 ◽  
Author(s):  
Mary A. Crawford ◽  
Bao Dang ◽  
John Hoang ◽  
Zhuangjie Li
Keyword(s):  
Mass Spectrometry ◽  
Kinetic Study ◽  
Relative Rate ◽  
Radical Reaction ◽  
Oh Radical ◽  
Discharge Flow ◽  
Rate Discharge

A Kinetic Study of the Reaction of OH with Xylenes Using the Relative Rate/Discharge Flow/Mass Spectrometry Technique

2009 ◽  
Vol 113 (46) ◽  
pp. 12942-12951 ◽  
Author(s):  
Deepali Mehta ◽  
Andrew Nguyen ◽  
Anthony Montenegro ◽  
Zhuangjie Li
Keyword(s):  
Mass Spectrometry ◽  
Kinetic Study ◽  
Relative Rate ◽  
Discharge Flow ◽  
Mass Spectrometry Technique ◽  
Rate Discharge ◽  
Spectrometry Technique

scholarly journals Molecular composition of fresh and aged secondary organic aerosol from a mixture of biogenic volatile compounds: a high-resolution mass spectrometry study

2015 ◽  
Vol 15 (10) ◽  
pp. 5683-5695 ◽  
Author(s):  
I. Kourtchev ◽  
J.-F. Doussin ◽  
C. Giorio ◽  
B. Mahon ◽  
E. M. Wilson ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
High Resolution Mass Spectrometry ◽  
Radical Reaction ◽  
Organic Aerosol ◽  
Molecular Composition ◽  
Oh Radicals ◽  
Oh Radical ◽  
High Resolution Mass ◽  
Resolution Mass

Abstract. Field observations over the past decade indicate that a significant fraction of organic aerosol in remote areas may contain highly oxidized molecules. Aerosol processing or further oxidation (aging) of organic aerosol has been suggested to be responsible for their formation through heterogeneous reaction with oxidants and multigenerational oxidation of vapours by OH radicals. In this study we investigated the influence of several aging processes on the molecular composition of secondary organic aerosols (SOA) using direct infusion and liquid chromatography high-resolution mass spectrometry. SOA was formed in simulation chamber experiments from ozonolysis of a mixture of four biogenic volatile organic compounds (BVOC): α-pinene, β-pinene, Δ3-carene and isoprene. The SOA was subsequently aged under three different sets of conditions: in the dark in the presence of residual ozone, with UV irradiation and OH radicals, and using UV light only. Among all studied conditions, only OH radical-initiated aging was found to influence the molecular composition of the aerosol and showed an increase in carbon oxidation state (OSC) and elemental O / C ratios of the SOA components. None of the aging processes produced an observable effect on the oligomers formed from ozonolysis of the BVOC mixture, which were found to be equally abundant in both "fresh" and "aged" SOA. Additional experiments using α-pinene as the sole precursor demonstrated that oligomers are an important group of compounds in SOA produced from both ozonolysis and OH radical-initiated oxidation processes; however, a completely different set of oligomers is formed under these two oxidation regimes. SOA from the OH-initiated oxidation of α-pinene had a significantly higher overall OSC and O / C compared to that from pure ozonolysis experiments confirming that the OH radical reaction is more likely to be responsible for the occurrence of highly oxidized species in ambient biogenic SOA.

Kinetic study of the gas-phase photolysis and OH radical reaction of E,Z- and E,E-2,4-Hexadienedial

1999 ◽  
Vol 31 (10) ◽  
pp. 689-697 ◽  
Author(s):  
Bj�rn Klotz ◽  
Ian Barnes ◽  
Karl-Heinz Becker
Keyword(s):  
Kinetic Study ◽  
Gas Phase ◽  
Radical Reaction ◽  
Oh Radical

scholarly journals Molecular composition of aged secondary organic aerosol generated from a mixture of biogenic volatile compounds using ultrahigh resolution mass spectrometry

2015 ◽  
Vol 15 (4) ◽  
pp. 5359-5389 ◽  
Author(s):  
I. Kourtchev ◽  
J.-F. Doussin ◽  
C. Giorio ◽  
B. Mahon ◽  
E. M. Wilson ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Uv Light ◽  
Radical Reaction ◽  
Organic Aerosol ◽  
Molecular Composition ◽  
Oh Radicals ◽  
Oh Radical ◽  
Ultrahigh Resolution ◽  
Ageing Processes ◽  
Resolution Mass

Abstract. Field observations over the past decade indicate that a significant fraction of organic aerosol in remote areas may contain highly oxidised molecules. Aerosol processing or further oxidation (ageing) of organic aerosol has been suggested to be responsible for their formation through heterogeneous uptake of oxidants and multigenerational oxidation of vapours by OH radicals. In this study we investigated the influence of several ageing processes on the molecular composition of secondary organic aerosols (SOA) using direct infusion and liquid chromatography ultrahigh resolution mass spectrometry. SOA was formed in simulation chamber experiments from ozonolysis of a mixture of four biogenic volatile organic compounds (BVOC): α-pinene, β-pinene, Δ3-carene and isoprene. The SOA was subsequently aged under three different sets of conditions: in the dark in the presence of residual ozone, with UV irradiation and OH radicals, and using UV light only. Among all studied conditions, only OH radical-initiated ageing was found to influence the molecular composition of the aerosol and showed an increase in carbon oxidation state (OSC) and elemental O/C ratios of the SOA components. None of the ageing processes produced an observable effect on the oligomers formed from ozonolysis of the BVOC mixture, which were found to be equally abundant in both "fresh" and "aged" SOA. Additional experiments using α-pinene as the sole precursor demonstrated that oligomers are an important group of compounds in SOA produced from both ozonolysis and OH radical-initiated oxidation processes; however, a completely different set of oligomers is formed under these two oxidation regimes. SOA from the OH radical-initiated α-pinene oxidation had a significantly higher overall OSC and O/C compared to that from pure ozonolysis experiments confirming that the OH radical reaction is more likely to be responsible for the occurrence of highly oxidised species in ambient biogenic SOA.

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