This project will develop a prototype Field-deployable Isotope-ratio Mass Spectrometer (FIMS) that will enable rapid, in situ determinations of the isotopic composition of CO2 and N2O. The FIMS instrument consists of a Trace Gas Sample Introduction System (TGSIS) interfaced to a Cycloidal-Focusing Mass Spectrometer (CFMS) that enables precise isotope measures within a portable instrument package powered by 24 volt batteries. The project will fabricate a micro-faraday array detector for the CFMS at the Space Science and Engineering Division at Southwest Research Institute and will train a new generation of biogeochemist through their participation in the development of the TGSIS. The project is targeting determinations of the isotopic composition of CO2 and N2O. However, the Faraday collector array enables measurement of other environmentally-important compounds, such as CH4 and H2O. Inherently, FIMS will compliment and exceed the abilities of laser-based systems by offering a wide range of isotope analyses as well as the capability of scanning for the abundances of volatile organic compounds.
Stable isotope analyses have become an integral component of a wide range of biogeochemical studies of the natural environment including animal migration, food resources, ecosystem metabolism, microbial dynamics and biosphere-atmospheric coupling. While the need for stable isotope data has become nearly ubiquitous in biogeochemistry, we have yet to realize an instrument that can be deployed in situ in remote environments to effect near real time measures of isotopic abundances of a wide range of materials. The biospheric-atmospheric exchange of trace gases is an example of one such area that would benefit from rapid and continuous isotope determinations of trace gases. Such measures would enable partitioning of net ecosystem exchange into photosynthetic and respiratory fluxes, determination of the origins of respired CO2, and quantification of the proportion of soil derived N2O from nitrification and denitrification.
In developing the FIMS system, the PI?s are anticipating the infrastructure needs of NEON and other large-scale monitoring networks by providing isotope analyses for a wide range of compounds at a scale not yet realized. The project will involve a team of 7 senior undergraduate students from the Electrical and Mechanical Engineering Departments to design and construct the electronics control system for the TGSIS. Thus, the instrumental design needs of the project will be met while enhancing the educational experiences of undergraduate students.
