SECONDARY EMISSION MASS SPECTROMETER

二次发射质谱仪

• 批准号: 4705590
• 负责人: L KELNER
• 金额: --
• 依托单位: DIVISION OF RESEARCH SERVICES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/4705590
• 关键词: alkaloids; analytical chemistry; cations; chemical structure; computers; emission spectrometry; ions; mass spectrometry; molecular weight; particle

We have initiated a systematic study of the energetics of various organic ions in relation to the different experimental conditions ion SIMS and FAB analysis. Knowledge of the energy distribution (ED) of secondary organic ions helps us to understand the mechanism of organic sputtering and provides information for the optimization of liquid SIMS. Based on our previous data, we proposed that the primary mechanism responsible for the emission of secondary organic ions is linear cascade sputtering, as this process results in the production of ions with lower kinetic energy. A major accomplishment in this FY was development - in collaboration with Teknivent. Inc. - of a data system based on an IBM PC-XT (256K), which was designed to control the quadrupole mass spectrometer of the SEMS system, and to scan the energy of secondary ions to produce energy distributions N(E)= f(E). The computer system was used to scan the main cylinder voltage (Vm) of the electrostatic energy analyzer (Bessel Box) as well as to control the tandem quadrupole mass spectrometer. The target bias (Vt) remained fixed during the energy scan, and the energy distribution was determined as a function of ion intensity versus (Vm-Vt). Complete spectra were stored for each step of the energy scan. We have studied the energy distribution of secondary organic ions of arginine as well as effects of various liquid matrices on this parameter. Matrices employed included glycerol, triethanolamine, triethylglycol, and polyethyleneglycols, as well as protonating systems such as trifluoromethanesulfonic acid (TFMSA) and tartaric acid (TA).

我们已经开始对各种有机物的能量学进行系统研究 离子与不同实验条件的关系离子 SIMS 和 FAB 分析。 了解二次有机物的能量分布 (ED) 离子有助于我们了解有机溅射的机理 为液体 SIMS 的优化提供信息。 基于我们的 之前的数据，我们提出负责的主要机制 二次有机离子的发射是线性级联溅射，因为这 该过程导致产生具有较低动能的离子。 本财年的一项重大成就是与以下机构合作进行开发： 特克尼文特。 Inc. - 基于 IBM PC-XT (256K) 的数据系统，该系统是 设计用于控制SEMS系统的四极杆质谱仪， 并扫描二次离子的能量以产生能量分布 N(E)=f(E)。 利用计算机系统扫描主缸电压 静电能量分析仪（贝塞尔盒）的 (Vm) 以及 控制串联四极杆质谱仪。 目标偏置 (Vt) 能量扫描期间保持固定，能量分布为 确定为离子强度与 (Vm-Vt) 的函数。 完整的光谱 存储能量扫描的每一步。 我们研究了二次有机离子的能量分布 精氨酸以及各种液体基质对该参数的影响。 使用的基质包括甘油、三乙醇胺、三乙基乙二醇和 聚乙二醇，以及质子化系统，例如 三氟甲磺酸（TFMSA）和酒石酸（TA）。