• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Microscreened endcap holes and buffer gas pressure tailoring for quadrupole ion trap mass spectrometry.
【24h】

Microscreened endcap holes and buffer gas pressure tailoring for quadrupole ion trap mass spectrometry.

机译：经过微筛分的端帽孔和缓冲气体压力定制装置，可用于四极离子阱质谱。

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

Field imperfections in the quadrupole ion trap (QIT) arise from the presence of holes in endcaps and from truncation of the hyperbolic electrodes. To reduce the nonlinear resonance effects, commercial 3-D QITs have a stretched axial configuration, which deviates from the theoretical z0 by 11%. Furthermore, the use of buffer gas, which helps trap and cool injected ions by reducing ion kinetic energy, focuses the ions into the trap center and away from the field imperfections. However, the increase in the distance superimposes higher order fields and consequently causes nonlinear resonance effects. Previous simulation studies from our lab have shown that microscreening the endcap holes could reduce field imperfections in the vicinity of the holes.;Analysis of perfluorotributylamine (PFTBA) fragment ion m/z 69 without buffer gas and with stretched geometry showed that an extra peak at m/z 67 increased in intensity. Reducing the z0 stretch to the theoretical value and with microscreened endcaps only reduced the "ghost" peak at m/z 67, but did not eliminate it. These combined results demonstrated that the compensation for stretching the trap may need to be optimized for use with microscreening methods. Among the microscreened endcap experiments without buffer gas, the reduced endcap spacing of 7.34 mm achieved the best overall performance in terms of reducing the ghost peak at m/z 67, although with some unexpected results. Furthermore, nonlinear resonances, which caused these ghost peaks to appear, were identified.;In addition, the potential for buffer gas pressure tailoring in quadrupole ion trap operation was investigated. The use of buffer gas during ion injection has beneficial effects, but in other events of the mass scan function, having gas inside the QIT can be disadvantageous. During the mass isolation and ejection events, fragile ions can collide with buffer gas molecules, causing fragmentation and degrading mass resolution. Currently, commercially available QITs maintain a constant buffer gas pressure (around 1 mTorr) that is a compromise. Here a multi-pulsed valve system is developed that delivers buffer gas only at points of the scan where it is needed. Results on evaluation of the gas profile output are presented as well as an application for the system.
机译：四极离子阱（QIT）中的场缺陷是由于端盖中存在孔以及双曲线电极的截断而引起的。为了减少非线性共振效应，商用3-D QIT具有拉伸的轴向配置，与理论z0的偏差为11％。此外，缓冲气体的使用通过减少离子动能来帮助捕集和冷却注入的离子，将离子聚焦到捕集阱中心并远离电场缺陷。但是，距离的增加会叠加高阶场，因此会引起非线性共振效应。我们实验室以前的模拟研究表明，对端帽孔进行微筛可以减少孔附近的场缺陷。分析没有缓冲气体且具有拉伸几何结构的全氟三丁胺（PFTBA）碎片离子m / z 69显示在m / z 67强度增加。将z0拉伸降低至理论值并使用经过微筛选的端帽，只能降低m / z 67处的“重影”峰，但不能消除。这些综合结果表明，可能需要优化用于诱集阱的补偿，以便与微筛选方法一起使用。在没有缓冲气体的情况下进行微筛分的端帽实验中，减少端帽间距为7.34 mm，就降低m / z 67处的重影峰而言，获得了最佳的总体性能，尽管结果有些出乎意料。此外，确定了导致这些鬼峰出现的非线性共振。；此外，研究了四极离子阱操作中缓冲气体压力调整的潜力。在离子注入过程中使用缓冲气体具有有益效果，但是在质量扫描功能的其他情况下，将气体存入QIT内部可能是不利的。在质量隔离和喷射事件期间，易碎的离子会与缓冲气体分子发生碰撞，从而导致碎裂并降低质量分辨率。当前，可商购的QIT维持恒定的缓冲气体压力（大约1 mTorr），这是一个折衷方案。在这里，开发了一种多脉冲阀系统，该系统仅在需要扫描的位置输送缓冲气体。提出了评估气体分布图输出的结果以及该系统的应用程序。

著录项

  • 作者

    Baluya, Dodge L.;

  • 作者单位

    University of Florida.;

  • 授予单位 University of Florida.;
  • 学科 Chemistry Analytical.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 106 p.
  • 总页数 106
  • 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