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CHEMISTRY
AND MASS SPECTROMETRY
Oak Ridge chemists pioneered methods of separating plutonium and other fission products from the spent uranium fuel at the Graphite Reactor, achieving the Laboratory's mission in the effort to end World War II. In the 1940s ORNL chemists were the first to conduct reactor-based neutron activation analyses. A famous use of these capabilities was the 1991 analysis of hair and nail samples from President Zachary Taylor's grave that refuted a historian's theory that he died from arsenic poisoning. In 1947 ORNL chemists measured ion-exchange properties of almost all the elements, producing a body of information invaluable for developing both analytical and industrial separations of numerous metals. In 1954 Sheldon Datz and Ellison Taylor pioneered molecular beam chemistry in which two beams of molecules are crossed, avoiding the complications of accounting for collisions with atoms in container walls and enabling better understanding of the dynamic interchange of atoms during chemical reactions. This crossed-beam scattering technique was further developed by two recipients of the 1986 Nobel Prize for chemistry. Carroll Johnson and Mike Burnett developed a revolutionary computer program for the visualization of molecular structure data determined by X-ray crystallography. The program, released in 1965, facilitated the generation of stereoscopic images of molecules for presentations and publications. In the 1980s ORNL groups led by Bob Mesmer and Mike Simonson obtained detailed data and developed predictive models for high-temperature aqueous solutions. These have been incorporated into process models widely used in the steam generator and geothermal energy industries. In the 1990s Bruce Moyer's group extended early ORNL-developed solvent extraction methods to the invention of a new process for separating cesium from nuclear wastes. The technology is being adopted for processing high-level waste at the Department of Energy's Savannah River Site. Starting in the late 1950s, ORNL's Gus Cameron, Joel Carter, Warner Christie, David Smith, and Ray Walker pioneered thermal ionization mass spectrometry methods for the precise isotopic quantification of very small amounts of nuclear materials. These techniques of sorting particles of uranium, plutonium, and other elements according to their mass-to-charge ratios have been further developed at ORNL and other laboratories for applications ranging from nuclear safeguards to life sciences. During the 1980s and 1990s, ORNL researchers Scott McLuckey, Gary Glish, Doug Goeringer, Gary Van Berkel, Kevin Hart, and Marc Wise made a number of fundamental discoveries in quadrupole ion-trap mass spectrometry. This instrument stores ions within an oscillating electric field that are ejected from the trap into a detector according to their mass-to-charge ratios. The work led to the development of the direct-sampling ion trap mass spectrometer, accepted in 2002 by the Environmental Protection Agency for on-site characterization of waste sites. This instrument also is the heart of the chemical biological mass spectrometer, developed by a team led by Wayne Griest for the U.S. Army for real-time detection of chemical and biological threat agents. In 1985 ORNL was the first DOE lab to use Fourier transform ion cyclotron resonance, another mass spectrometer that combines electrostatic and magnetic fields to trap ions. Bob Hettich and Michelle Buchanan developed techniques for applying this instrument's mass-resolving power to analysis of DNA and proteins, linking these analytical tools to the life sciences. During the 1990s, by improving secondary ion mass spectrometers, Peter Todd imaged and analyzed target molecules in whole tissues, including neurotransmitters in brain tissue. McLuckey, Van Berkel, and Glish were the first to couple the electrospray ionization technique with the ion trap mass spectrometer, enabling the identification of proteins. Bill Partridge and others developed the spatially resolved capillary inlet mass spectrometer measurement strategy to characterize reactions within after-treatment devices used to remove pollutants from diesel engine exhaust gases. This technology is being adopted by government, academic, and industrial research labs, including those of Cummins, Ford, and Engelhard. ORNL's chemistry activities continue to support DOE's missions of promoting energy production and efficiency and protecting people and the environment in and around energy production units. |
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Web site provided by Oak Ridge National Laboratory's Communications and External Relations |
