Project Summary (1995-2000)

The primary goal of this project is to improve risk assessment by emphasizing elemental speciation studies for samples with environmental health significance at ultra-trace levels. This significant new approach is simultaneously generating both quantitative analyses and structural identification data at sub-nanogram to sub-picogram levels. These studies are utilizing low-pressure (LP) and alternate gas source glow discharges (GD) for elemental species detection. Because of their nature and the high information level available from such sources, special attention must be given to sample introduction methods. This project has already shown that gaseous sample introduction methods are readily viable. However, liquid sample introduction is the next challenge since solvent loading compromises the ability of these plasmas for analytical use. Therefore, to complement these potentially powerful new sources, low-flow, low-volume sample introduction methods are being investigated to minimize solvent loading. It is fortunate that the liquid sample introduction methods required for these plasmas are also excellent methods for separation of the chemical species of interest to our elemental speciation studies. These are capillary electrophoresis (CE) and microbore liquid chromatography (LC). With appropriate combinations of these separation techniques and dry aerosol production methods, it will be possible to have high resolution separations of highly important elemental species, such as bioselenium compounds with ultra-trace levels of detection.