Thesis
Measurements of a volatile organic compounds in diesel and gasoline exhaust using proton-transfer reaction mass spectrometry
Washington State University
Master of Science (MS), Washington State University
2012
Handle:
https://hdl.handle.net/2376/101264
Abstract
A Proton Transfer Reaction Mass Spectrometer (PTR-MS) was used to measure the abundance of organics in diesel and gasoline engine exhaust mixtures as part of a health effects study conducted at the Lovelace Respiratory Research Institute. To aid in the interpretation of PTR-MS mass spectra of exhaust mixtures, laboratory experiments were conducted to better understand the sensitivity and fragmentation patterns for a series of alkyl substituted monoaromatics and polyaromatic hydrocarbons found in exhaust. Monoaromatic compound fragmentation was examined for drift tube conditions of 80, 100, 120, and 150 Td. It was observed that compounds with ethyl or isopropyl groups attached to a benzene ring are susceptible to fragmentation and can therefore produce positive inferences in the measurement of benzene and toluene. The sensitivity of the PTR-MS to the PAH compounds acenaphthylene, acenaphthene, and biphenyl was determined by preparing standards in dichloromethane and using a syringe pump to dynamically dilute evaporated standard solutions into a flow of hot dry nitrogen gas. The sensitivity was found to be 3.1 ±0.3, 3.2 ±0.3, and 3.2 ±0.6 Hz per MHz H3O+ iv per ppbV respectively at the 80 Td drift tube condition. The PAH compounds did not fragment and therefore can be monitored at their M+1 ion. The mass spectrums of diesel and gasoline exhaust were quite similar with a few exceptions. While the gasoline exhaust had much higher concentrations of volatile organic compounds (VOCs), the abundance of compounds relative to benzene was similar. Low engine loads had the highest concentrations for both engines. The data show some evidence that in diesel and gasoline exhaust mixtures with high particle mass concentrations, PAH compounds partition from the gas phase to the particle phase and may offer an explanation as to why gasoline and diesel exhaust mixtures are more toxic than either alone.
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Details
- Title
- Measurements of a volatile organic compounds in diesel and gasoline exhaust using proton-transfer reaction mass spectrometry
- Creators
- Mylene Gueneron
- Contributors
- Tom Jobson (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Civil and Environmental Engineering, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525015901842
- Language
- English
- Resource Type
- Thesis