• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Fundamentals of ambient metastable-induced chemical ionization mass spectrometry and atmospheric pressure ion mobility spectrometry.
【24h】

Fundamentals of ambient metastable-induced chemical ionization mass spectrometry and atmospheric pressure ion mobility spectrometry.

机译：环境亚稳态诱导化学电离质谱和大气压力离子迁移谱的基础知识。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Molecular ionization is owed much of its development from the early implementation of electron ionization (EI). Although dramatically increasing the library of compounds discovered, an inherent problem with EI was the low abundance of molecular ions detected due to high fragmentation leading to the difficult task of the correct chemical identification after mass spectrometry (MS). These problems stimulated the research into new ionization methods which sought to "soften" the ionization process. In the late 1980s the advancements of ionization techniques was thought to have reached its pinnacle with both electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI). Both ionization techniques allowed for "soft" ionization of large molecular weight and/or labile compounds for intact characterization by MS. Albeit pervasive, neither ESI nor MALDI can be viewed as "magic bullet" ionization techniques. Both techniques require sample preparation which often included native sample destruction, and operation of these techniques took place in sealed enclosures and often, reduced pressure conditions.;New open-air ionization techniques termed "ambient MS" enable direct analysis of samples of various physical states, sizes and shapes. One particular technique named Direct Analysis In Real Time (DART) has been steadily growing as one of the ambient tools of choice to ionize small molecular weight ( 1000 Da) molecules with a wide range of polarities. Although there is a large list of reported applications using DART as an ionization source, there have not been many studies investigating the fundamental properties of DART desorption and ionization mechanisms.;The work presented in this thesis is aimed to provide in depth findings on the physicochemical phenomena during open-air DART desorption and ionization MS and current application developments. A review of recent ambient plasma-based desorption/ionization techniques for analytical MS is presented in Chapter 1. Chapter 2 presents the first investigations into the atmospheric pressure ion transport phenomena during DART analysis. Chapter 3 provides a comparison on the internal energy deposition processes during DART and pneumatically assisted-ESI. Chapter 4 investigates the complex spatially-dependent sampling sensitivity, dynamic range and ion suppression effects present in most DART experiments. New implementations and applications with DART are shown in Chapters 5 and 6. In Chapter 5, DART is coupled to multiplexed drift tube ion mobility spectrometry as a potential fieldable platform for the detection of toxic industrial chemicals and chemical warfare agents simulants. In Chapter 6, transmission-mode DART is shown to be an effective method for reproducible sampling from materials which allow for gas to flow through it. Also, Chapter 6 provides a description of a MS imaging platform coupling infrared laser ablation and DART-like phenomena. Finally, in Chapter 7 I will provide perspective on the work completed with DART and the tasks and goals that future studies should focus on.
机译：分子电离的大部分发展归功于电子电离（EI）的早期实施。尽管极大地增加了发现的化合物库，但EI的固有问题是由于高碎片导致检测到的分子离子丰度低，导致质谱（MS）鉴定正确的困难。这些问题激发了对新的电离方法的研究，这些方法试图“软化”电离过程。在1980年代后期，人们认为电离技术的进步已经达到了顶峰，电喷雾电离（ESI）和基质辅助激光解吸/电离（MALDI）均是如此。两种电离技术都允许大分子量和/或不稳定化合物的“软”电离，以通过MS完整表征。尽管普遍存在，但ESI和MALDI都不能被视为“魔弹”电离技术。两种技术都需要样品制备，这通常包括天然样品的破坏，并且这些技术的操作在密封的外壳中进行，并且通常在减压条件下进行。新的露天电离技术称为“环境MS”，可以直接分析各种物理状态的样品，大小和形状。一种名为实时实时直接分析（DART）的特殊技术已经稳步发展为一种选择的环境工具，可以电离具有宽范围极性的小分子量（<1000 Da）分子。尽管使用DART作为电离源的已报道的应用程序很多，但是尚未进行很多研究来研究DART解吸和电离机理的基本特性。本论文的目的是提供有关理化作用的深入发现。露天DART解吸和电离质谱过程中的现象以及当前的应用开发。第1章概述了用于分析型MS的基于环境等离子体的最新解吸/电离技术。第2章介绍了DART分析过程中对大气压离子传输现象的首次研究。第3章比较了DART和气动辅助ESI期间的内部能量沉积过程。第4章研究了大多数DART实验中存在的复杂的空间依赖性采样灵敏度，动态范围和离子抑制效应。第5章和第6章介绍了DART的新实现和应用。在第5章中，DART与多路漂移管离子迁移谱仪耦合，可作为检测有毒工业化学品和化学战剂模拟物的潜在现场平台。在第6章中，传输模式DART被证明是一种从可允许气体流过的材料中重现采样的有效方法。同样，第6章介绍了结合红外激光烧蚀和DART现象的MS成像平台。最后，在第7章中，我将对DART完成的工作以及将来的研究应重点关注的任务和目标提供透视图。

著录项

  • 作者

    Harris, Glenn A.;

  • 作者单位

    Georgia Institute of Technology.;

  • 授予单位 Georgia Institute of Technology.;
  • 学科 Chemistry Analytical.;Physics Fluid and Plasma.
  • 学位 Ph.D.
  • 年度 2011
  • 页码 211 p.
  • 总页数 211
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号