Characterization and Optimization of Atomic Spectrometric Processes and Techniques

在分析和表面化学计划的支持下， 加里博士M. Hieftje将继续进行旨在提高 灵敏度、精密度、准确度和实用程度 原子光谱分析在一组调查中， 将采用专门开发的技术来阐明 溶质粒子蒸发和原子形成机制 用于多元素分析的火焰和等离子体。 对这些事件的澄清预计将减少 不完全汽化引起的元件间干扰。 在研究的第二个领域，稀有气体等离子体将是 研究以确定他们如何负责 激发原子和离子。将特别强调 放在了解电子的特性， 这种放电和电子在转移过程中的作用 等离子体能量到分析物原子和离子。 在第三个领域， 等离子体源质谱中的干扰源 将进行调查。一个典型的等离子体源， 光谱仪本身，以及分离这些光谱仪的接口， 将被研究，以了解大众 光谱采样过程影响等离子体， 大气压气体通过 中压接口到质谱仪，以及如何 质谱仪中的空间电荷效应可以影响 精度、精度和动态范围 测量.最后，限制使用 辉光放电灯作为一个来源将探讨，与特殊的 注意稀有气体溅射的性质和速率， 源 原子光谱法是一种灵敏度高、操作简便的方法 用于金属的鉴别和定量测量 在生物和环境样本中。的结果 预计这些项目将有助于大幅度改善 这种方法的实用性和准确性。

With support from the Analytical and Surface Chemistry Program Dr. Gary M. Hieftje will continue studies intended to enhance the sensitivity, precision, accuracy and degree of utility of atomic spectrometric analysis. In one group of investigations, specially developed techniques will be employed to eluciate the mechanism of solute particle vaporization and atom formation in flames and plasmas of the kind used for multielement analysis. Clarification of these events is expected to reduce interelement interferences caused by incomplete vaporization. In a second area of investigation, rare-gas plasmas will be studied in an effort to determine how they are responsible for excitation of atoms and ions. Particular emphasis will be placed on understanding the characteristics of electrons in such discharges and the role electrons play in transferring plasma energy to analyte atoms and ions. In the third area, the sources of interferences in plasma source-mass spectrometry will be investigated. A typical plasma source, the mass spectrometer itself, and the interface that separates these will be examined in an effort to understand how the mass spectrometric sampling process influences a plasma, how the atmospheric-pressure gases are extracted through a medium-pressure interface into the mass spectrometer, and how space-charge effects in the mass spectrometer can influence accuracy, precision, and dynamic range in the resulting measurement. Finally, the factors that limit the utility of the glow-discharge lamp as a source will be explored, with special attention to the nature and rate of rare-gas sputtering in such sources. Atomic spectroscopy is a highly sensitive and convenient method for the identification and quantitative measurement of metals in biological and environmental samples. The results of this project are expected to contribute to substantial improvements in the utility and accuracy of this method.