Book Description

This research deals with radiochromatographic separations in neutron activation analysis of trace elements in serum. Understanding the metabolic roles of trace elements as well as their toxicological effects in biological systems has been limited by the sensitivity and selectivity of existing analytical techniques. The lack of human serum concentration data for many trace elements prevents optimum clinical utilization of this extremely powerful diagnostic tool. Neutron activation analysis has extremely low limits of detection for a large number of elements. However, interference from those elements present in human serum at relatively high levels must be eliminated before even a high-resolution solid state detector can be effective. The utilization of high sensitivity sodium iodide detectors requires still more separation. Chromatographic separations of metal chelates were developed for both pre- and post-irradiation separations. Quantitative elution from the gas chromatographic column for fluorine substituted beta-diketonate complexes of Cr, Cu, Mn, Fe, Be, Lu, and Gd was studied; recoveries between 52 and 92% were found. Extensive studies of decomposition and adsorption losses in the system are reported. Construction and evaluation of various sampling systems, transfer lines, and counting geometries are included. A completely reversible counting geometry for radioactive metal chelates using wide-range temperature and carrier gas control to trap and subsequently release eluate fractions is described. Also included is an apparatus for carrying out chelate separations from solutions whose large volumes preclude gas chromatographic injection. The successful use of a chelating ion exchange resin in human serum neutron activation analysis is reported. Operating conditions which optimize sodium removal with respect to sample loss are described.