Electrothermal Vaporization Introduction for ICP-MS

该项目由德克萨斯大学奥斯汀分校的化学教授詹姆斯·A·霍尔科姆指导，由化学系的分析和表面化学项目支持。本研究将固体样品和微量样品引入电感耦合等离子体质谱(ICPMS)。电热汽化(ETV)将作为进样方法。将进行一系列基础性研究，以了解材料是如何运输到国际比较方案的，以及影响这一过程的参数。这项工作包括对载体颗粒大小对分析物传输效率的影响以及分析物与载体结合类型对传输的影响的研究。样品运输调查的第二个方面将涉及开发外部生成的载体。为此要探索的两种方法是苯的热解形成碳颗粒，以及气态四氯化钛与水蒸气反应形成二氧化钛颗粒。一种完全不同的方法将涉及使用去溶解的雾化器产生的气雾剂，这些气雾剂是通过吸入选定的盐而产生的。另一种产生碳颗粒的方法是在钯存在的情况下进行氧气灰化。最后，为了校正空间电荷对分析物传输的影响，将探索自动透镜校正程序，以提供对ETV-ICP-MS产生的瞬时信号的动态校正技术。化学分析仪器必须具有将待分析样品引入仪器的手段。在某些情况下，这需要改变感兴趣物种的物理状态，例如，从液体到气体。通常，并不是所有的样品都进入仪器的测量区域，因此样品的运输效率非常重要。本课题就是针对电感耦合等离子体质谱仪所遇到的这个问题而展开的。

This project under the direction of Chemistry Professor James A. Holcombe of the University of Texas, Austin, is supported by the Analytical and Surface Chemistry Program in the Division of Chemistry. The research concerns the introduction of solid samples and microsamples into the inductively coupled plasma-mass spectrometer (ICP-MS). Electrothermal vaporization (ETV) will be developed as the method of sample introduction. A set of fundamental studies will be done to provide an understanding of how material is transported to the ICP and the parameters influencing the process. Included in the work are studies of the influence of carrier particle size on the efficiency of analyte transport and the impact on transport of the nature of the type of association of analyte with carrier. A second aspect of the sample transportation investigations will be concerned with development of externally generated carriers. Two of the methods to be explored for this purpose are the pyrolysis of benzene to form carbon particles, and the reaction of gaseous titanium tetrachloride with water vapor to form titanium dioxide particles. An entirely different approach will involve the use of desolvated nebulizer-generated aerosols produced from aspiration of selected salts. Another method to generate carbon particles will involve oxygen ashing in the presence of palladium. Finally, to correct for space charge effects on analyte transport, automatic lens correction procedures will be explored to provide a dynamic correction technique for the transient signal produced by ETV-ICP-MS. Instruments for chemical analysis necessarily must have a means of introducing the sample to be analyzed into the instrument. In some cases, this requires a change in the physical state of the species of interest, for example, from a liquid to a gas. Often, not all of the sample enters the measurement zone of the instrument and therefore the efficiency of transport of sample is of great interest. This project is concerned with this problem as it is encountered with the inductively coupled plasma-mass spectrometer.