Studies of Secondary Processes within High Pressure Electron Capture Ion Sources

这个项目是在分析和表面化学的一般领域，在质谱和气相色谱的子领域。在可用于环境或生物医学上重要的有机化合物痕量分析的方法中，基于高压，气相，电子捕获反应与毛细管柱气相色谱相结合的方法已被证明具有优越的潜力。两种这样的方法包括高压电子捕获质谱仪（HPECMS）和电子捕获检测器（ECD）。在这个项目的过程中，Grimsrud教授和他的学生将进一步开发利用HPECMS和ECD的技术，并将详细阐述它们所依赖的基本原理。尽管HPECMS在痕量化学分析方面具有巨大的潜力，但其观察到的“电子捕获光谱”的基本基础往往不能单独用电子捕获过程来解释，因为人们对次级过程知之甚少。该项目的一个目标是通过揭示这些二次过程的存在和性质，并通过确定消除其对分析的有害影响和增强其有益影响的方法，提高HPECMS的分析效用。为此目的，将建造一个专门的脉冲电子束质谱仪，与传统的商业仪器相比，它可以更好地控制和改变实验参数。此外，本研究将通过在该装置内使用光子诱导负离子的电子分离来扩展ECD的能力。

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.