Secondary Ion Mass Spectrometry with Massive Projectiles

使用大型射弹进行二次离子质谱分析

• 批准号: 0449312
• 负责人: Emile Schweikert
• 金额: --
• 依托单位: Texas A&M Research Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-01 至 2009-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0449312&HistoricalAwards=false
• 关键词: Secondary; Ion; Mass; Spectrometry; Massive

Professors Emile Schweikert and Stanislav Verkhotrov of Texas A&M University are supported by the Analytical and Surface Chemistry program to investigate the use of gold clusters as projectiles for the detection of attomol amounts of analyte and for identifying molecules colocated on surfaces within submicron distances. The experimental procedure is secondary ion mass spectrometry (SIMS), with two key differences: the nature of the projectile and the mode of bombardment with individual projectiles resolved in time and space. In previous NSF-supported work, this lab worked with a liquid metal ion source which produces a wide range of gold clusters, e.g. 200 gold atoms with a +4 charge. This work will investigate the fundamental issues related to the efficiency of massive gold projectiles to generate secondary ions. The PI's will also develop negative ion mass spectrometry using the gold particles to assess spatial resolution. A sequence of individual projectiles spaced one millisecond apart is focused on a small surface area. The impacts which occur are each recorded individually via the emitted electrons and correlated with the time-of-flight data of the secondary ions detected from the same event. These data should allow compilation of a chemical map giving a 2D or 3D distribution of molecules with an anticipated spatial resolution of 25 nm. The development of mass spectrometry as a chemical microscopy is very important for achieving the goal of chemically mapping biological structures such as the single cell. These images will lead to a greater understanding of how the cell works and interacts with other cells. Chemical imaging with nanoscale resolution will also be very useful in characterizing nanoparticles.

Emile Schweikert和Stanislav Verkhotrov教授在分析和表面化学项目的支持下，研究了使用金簇作为抛射体来检测阿托摩尔量的分析物，并识别亚微米距离内表面上共存的分子。实验程序是二次离子质谱法（西姆斯），有两个关键的区别：弹丸的性质和轰击模式与个别弹丸解决在时间和空间。 在之前NSF支持的工作中，该实验室使用了一种液态金属离子源，该离子源产生了各种各样的金簇，例如200个带+4电荷的金原子。 这项工作将调查的基本问题，大量的黄金弹丸产生二次离子的效率。 PI还将开发使用金颗粒的负离子质谱法，以评估空间分辨率。 间隔一毫秒的一系列单个射弹集中在一个小的表面区域。 所发生的撞击分别通过发射的电子记录，并与从同一事件中检测到的二次离子的飞行时间数据相关联。 这些数据应允许编辑化学图，给出分子的2D或3D分布，预期空间分辨率为25 nm。 质谱作为化学显微镜的发展对于实现化学映射生物结构（如单细胞）的目标非常重要。 这些图像将有助于更好地了解细胞如何工作以及与其他细胞的相互作用。 具有纳米级分辨率的化学成像在表征纳米颗粒方面也将非常有用。