This project is in the general area of analytical and surface chemistry and in the subfields of mass spectrometery and gas chromatography. Of the methods available for the trace analysis of environmentally or biomedically important organic compounds, those based on high pressure, gas phase, electron capture reactions in combination with capillary column gas chromatography have been shown to possess superior potential. Two such methods incorporate the High Pressure Electron Capture Mass Spectrometer (HPECMS) and the Electron Capture Detector (ECD). During the course of this project, Professor Grimsrud and his students will further develop techniques which utilize the HPECMS and the ECD and will elaborate the underlying principles on which they depend. In spite of its great potential for trace chemical analysis, the fundamental basis of "Electron Capture Spectra" observed by HPECMS is often not explicable in terms of electron capture processes, alone, because of poorly understood secondary processes. One goal of this project is to improve the analytical utility of HPECMS by revealing the existence and nature of such secondary processes and by determining the means by which their detrimental effects on analysis can be eliminated and their beneficial effects enhanced. To this end, a specialized pulsed electron beam mass spectrometer will be constructed which will allow greater control and variation of experimental parameters than is possible with conventional, commercial instruments. Also, this research will extend the capability of the ECD through the use of photon-induced electron detachments of negative ions within this device.