RESEARCH
INSTRUMENT DEVELOPMENT
PUBLICATIONS |
Continuous-flow isotope ratio mass spectrometry has rapidly become an innovative tool for investigations of isotopic compositions of atmospheric trace gases. An integral part of my research is to develop novel techniques to measure small differences in 13C/12C and D/H isotope ratios, as small as 1 part in a million, in such trace species as methane, molecular hydrogen, methyl chloride, and formaldehyde. Some of these gases exist in the atmosphere at abundances lower than one part per billion which pushes the sensitivity limits of existing technology.
APPLICATIONS TO TRACE GASES
In our laboratory we use these state-of-the-art analytical techniques to analyze air samples collected world wide. Recent work has included the analysis of trace gases in source regions including urban atmospheres, rice paddies, and landfills. In remote atmospheres we have analyzed air collected aboard ocean-going vessels, the NASA ER-2 aircraft, and from stationary sites including Cheeka Peak, WA and Montana de Oro, CA. Current projects are aimed at characterizing the isotopic composition of atmospheric methane, molecular hydrogen, methyl chloride, and formaldehyde from sources and in the remote atmosphere. Our research also examines kinetic isotope effects in atmospheric chemical oxidation reactions (e.g., CH4+OH) in laboratory and field settings which impact observed isotopic compositions of these trace species.