Ion Sampling and Transport in Plasma Source Mass Spectrometers

该项目得到了分析和表面化学计划的支持，旨在确定那些限制大气压等离子体质谱灵敏度和准确性的因素。在这项为期三年的标准补助金任期内，杨百翰大学的Paul Farnsworth教授和他的学生将研究从电感耦合等离子体源提取离子束并将其导入质谱仪进行分析的过程。将使用两种技术来描述这一过程。第一种方法是在离子束的路径上放置一个镍网，持续一段固定的时间，然后取出进行扫描电子显微镜分析。第二种方法是基于离子羽流中选定离子物种的激光诱导荧光。这些研究将使离子束提取过程有更准确的图像，并将使设计高效的电感耦合等离子体质谱仪成为可能。电感耦合等离子体质谱正迅速成为从环境到生物技术等领域中各种样品的低水平元素组成测定的首选方法。目前，离子在这些器件中的传输效率是其性能的限制因素。杨百翰大学的保罗·法恩斯沃斯和他的学生正在描述离子提取过程。这些研究的结果可能会使人们能够设计出精度更高、灵敏度更高的新一代光谱仪。

This project, supported in the Analytical and Surface Chemistry Program, is directed towards identifying those factors which limit the sensitivity and accuracy of atmospheric pressure plasma based mass spectrometry. During the tenure of this three-year standard grant, Professor Paul Farnsworth and his students at Brigham Young University will investigate the processes under which an ion beam is extracted from an inductively coupled plasma source, and directed into a mass spectrometer for analysis. Two techniques will be used to characterize this process. The first involves placing a nickel mesh in the path of the ion beam for a fixed time period prior to removal for analysis by scanning electron microscopy. The second approach is based on laser induced fluorescence of selected ionic species within the ion plume. These studies will allow a much more accurate picture of the ion beam extraction process, and should permit the design of highly efficient inductively coupled plasma mass spectrometers. Inductively coupled plasma mass spectrometry is rapidly becoming the method of choice for low level determinations of elemental composition for a wide range of samples in areas ranging from the environment to biotechnology. At present, the efficiency of ion transport in these devices is the limiting factor in their performance. Paul Farnsworth and his students at Brigham Young University are characterizing the ion extraction processes. The results from these studies could allow a new generation of spectrometers with improved accuracy and higher sensitivities to be designed.