Thermospray Mass Spectrometry Ionization Processes Fundamental Mechanisms for Speciation, Separation and Characterization of Organic Complexants in DOE Wastes

The overall objective of this research is to develop and enhance our understanding of the chemical equilibria for major organic complexant species and their products with metals in aqueous mixtures such as those found in DOE radioactive tank wastes. Our approach to achieving this objective is a series of incremental studies involving cooperative efforts at Oak Ridge National Laboratory (ORNL) and at the University of Minnesota. Investigations at ORNL are characterizing soft ionization mass spectrometry processes for the complexant species by developing and interpreting positive and negative ion thermospray mass spectrometry (TMS) of some organic complexants and their decomposition products and relating the spectral distributions to gas phase chemistry. Subsequently this knowledge of the gas phase chemistry will be related to known solution chemistry behavior. At the University of Minnesota liquid chromatography separations on zirconia-based chromatographic supports are being studied in order to understand the separation of organic complexants and the products formed by complexants with metals in complex aqueous mixtures; and thereby define the conditions needed to introduce a simplified chemical stream into the mass spectrometer. Ultimately the knowledge gained from these parallel efforts will be combined at ORNL to characterize the complexant species in a multi-component aqueous mixture with the final objective being to develop the analytical capability needed to define chemical equilibria for complexant species in DOE waste streams