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

Description: 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.
Date: June 1, 1999
Creator: Caton, John E.; Bostick, Debra, T.; Carr, Peter W. & Mabbott, Gary
Partner: UNT Libraries Government Documents Department

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

Description: The overall objective is to develop and enhance our understanding of chemical equilibria for major organic complexant species (chelators, chelator fragments, small organic acids and their products) in multi-component aqueous matrices such as the mixtures of DOE stored wastes. To progress toward this objective, organic complexants must be separated and speciated in mixtures of high ionic strength. HPLC employing zirconia-based stationary phases is being studied in order to understand the separation requirements for organic complexants and the products formed by complexants with metals in complex aqueous mixtures. Separated complexant species will then be characterized using positive and negative ion thermospray mass spectrometry (TSMS). The final goal is to develop the analytical capability needed to define chemical concentration and equilibria for complexant species in DOE waste streams.
Date: June 1, 1999
Creator: Caton, John E.; Bostick, Debra T.; Carr, Peter W. & Mabbott, Gary
Partner: UNT Libraries Government Documents Department

Fast Gradient Elution Reversed-Phase HPLC with Diode-Array Detection as a High Throughput Screening Method for Drugs of Abuse

Description: A new approach has been developed by modifying a conventional gradient elution liquid chromatograph for the high throughput screening of biological samples to detect the presence of regulated intoxicants. The goal of this work was to improve the speed of a gradient elution screening method over current approaches by optimizing the operational parameters of both the column and the instrument without compromising the reproducibility of the retention times, which are the basis for the identification. Most importantly, the novel instrument configuration substantially reduces the time needed to re-equilibrate the column between gradient runs, thereby reducing the total time for each analysis. The total analysis time for each gradient elution run is only 2.8 minutes, including 0.3 minutes for column reequilibration between analyses. Retention times standard calibration solutes are reproducible to better than 0.002 minutes in consecutive runs. A corrected retention index was adopted to account for day-to-day and column-to-column variations in retention time. The discriminating power and mean list length were calculated for a library of 47 intoxicants and compared with previous work from other laboratories to evaluate fast gradient elution HPLC as a screening tool.
Date: December 30, 2005
Creator: Carr, Peter W.; Fuller, K.M.; Stoll, D.R.; Steinkraus, L.D.; Pasha, M.S. & Hardin, Glenn G.
Partner: UNT Libraries Government Documents Department