Aqueous Phase Branching Ratios of Light Alkyl Nitrates

Allyson Wright is a fourth year graduate student in Dr. Shepson lab. Her research project focuses on the investigation of the aqueous phase yield of light alkyl nitrates via the oxidation of volatile organic compounds (VOCs).

The oxidation of VOCs has two pathways in the presence of excess NO; the first converts NO to NO2 (Reaction 3a); the second produces an organic nitrate (Reaction 3b).

OH  +  VOCs  →     H2O  +  RO2        (1)
RO2  + NO      →     ROONO*             (2)
     ROONO*     →     RO  +  NO2        (3a)
     ROONO*     →     RONO2               (3b)

These two pathways have been studied extensively in the gas phase because their respective products play a significant role in the earths atmospheric cleansing. However, to date the aqueous phase studies of this reaction pathway have been limited. Therefore, this research will help to advance the understanding of why significantly higher branching ratios of alkyl nitrates have been reported in aqueous solution compared to the gas phase.

To date Allyson has spent much of her time establishing her experimental setup which includes a reaction chamber, solar simulator, purge and trap, gas chromatograph (GC) and electron capture detector (ECD). She is currently collecting laboratory data in preparation of testing field samples including cloud water from ALAR and snowpack samples from OASIS 2009.