Roger Adams: Scientist and Statesman by D. Stanley Tarbell and Ann Tracy Tarbell
Examines the life of Roger Adams — a man unparalleled in his contribution to the development of organic chemistry. A comprehensive biographical sketch of Roger Adams, whose work was important in the development of American chemistry and chemical education. Adams's early years, education, and career achievements in academia, industry, research, and government are described. His contributions to Illinois chemistry in particular and the education of chemists are expounded. His service to the American Chemical Society and other professional organizations are also discussed. CONTENTS
Science
Lasers used to analyze rare-earth elements Researchers at Los Alamos National Laboratory, New Mexico, are applying laser spectroscopy techniques to solve some of the practical problems of analyzing rare-earth elements. The research team, which includes staff members Alexander J. Gancarz Jr. and Nicholas S. Nogar, postdoctoral fellow Charles M. Miller, and laboratory consultant William R. Shields, uses gas-phase laser ionization to distinguish between isotopes of two rare-earth elements—lutetium and ytterbium—that have the same mass and very similar chemical properties. The researchers couple this laser separation with conventional mass spectroscopic analysis. The effect is to increase the selectivity of their analysis for lutetium over ytterbium by 50,000 without the corresponding decrease in sensitivity that ordinarily would accompany such a selectivity gain. "We have put together bits and pieces of other people's techniques and used them on real analytical samples," says Nogar. Other researchers have worked principally with carefully prepared samples, such as pure metals, and not what Nogar calls the "real-life, dirty samples" encountered in ordinary analytical chemistry. The Los Alamos project draws particularly on earlier work in laser spectroscopy by G. Sam Hurst and associates at Oak Ridge National Laboratory, Nogar says. The Los Alamos project is directed toward a specific analytical problem—separating the low levels of lutetium-174 produced when a nuclear
weapon is tested from a roughly equal amount of ytterbium-174 that occurs naturally in earth samples. Lutetium, in its naturally occurring isotopes 175 and 176, often is added to a nuclear weapon as a detector element during weapons testing, Gancarz explains. In the course of a thermonuclear reaction a small amount (one atom in 106) of the lutetium-175 is converted to lutetium-174. Having an accurate measure of how much lutetium-174 is formed helps to evaluate the performance of the nuclear weapon. However, when a weapon is detonated underground, the lutetium produced becomes mixed with the other elements in the ground at the test site. Particularly difficult, from the viewpoint of analysis, is its mixture with ytterbium-174, which is almost always present in low amounts in the ground. In the new technique, the earth sample undergoes preliminary chemical purification which produces a mixture of rare-earth elements in very acidic, aqueous solution. This solution is placed on the metal filament of a mass spectrometer and the water removed, leaving a film on the filament that contains the rare-earth elements from the sample. The filament is heated to vaporize these elements and a laser beam in the blue visible region that selectively will ionize only the lutetium is passed through the vapor. The lutetium ions thus produced are swept through the mass spectrometer in a conventional manner and measured in the instrument's detector. D
Introduction · Early Years and College · Germany and Harvard, 1912-16 · Illinois, 1916-26 · Academic Progress · Service and Research to 1942 · Government Service, 1940-48 · Illinois and Research, 1943-67 · Broader Horizons · Career Achievements of Roger Adams's Ph.D.s, 1918-58 · Career Achievements of Roger Adams's Postdoctorates, 1936-59 240 pages (1981) Clothbound US & Canada $13.95 Export $16.95 LC 81-17625 ISBN 0-8412-0598-1 Order from: SIS Dept. 16 American Chemical Society 1155 Sixteenth St., N.W. Washington, D.C. 20036 or CALL TOLL FREE 800-424-6747 and use your credit card.
Miller checks laser beam entering mass spectrometer sample chamber on right 30
C&EN March 15, 1982
