低真空度下四极场中离子操作模式研究

发布时间：2018-06-14 14:29

本文选题：低真空度 + 四极场　；参考：《哈尔滨工业大学》2015年硕士论文

【摘要】：随着质谱技术的快速发展,质谱仪在生活中发挥越来越重要的作用。绝大部分的质谱仪虽然性能高,但是必须工作在高真空度条件下,且体积大,重量重,功耗大,不方便携带,也不方便进行现场实时分析。本文以二维线性离子阱为模型,研究低真空度条件下带电离子在理想四极场中的操作模式。首先简单介绍了本文使用的仿真软件——SIMION,并从理论角度出发,分析了高真空条件下带电离子在理想四极场中的基本规律,包括马修方程、离子运动稳定区、离子久期频率等。接着介绍两种常见的带电离子与惰性气体分子之间的弹性碰撞模型,即Langevin模型和Hardsphere模型,通过仿真比较,选出合适的模型;然后将理想情况下的马修方程添加阻尼项完成修正,并利用数学方法求得低真空度下的离子运动稳定区。最后介绍了多个评价质谱仪器性能好坏的标准,详细介绍了实现质量分析的三个重要步骤以及两种离子出射方式,并给出经典的离子操作模式;通过SIMION建模仿真,考虑不同的参数如冷却时间,辅助AC信号幅度、频率等对质谱仪分辨率的影响,最终得到低真空下离子操作模式参数。在满足一定性能要求的前提下,本论文的研究可以使质谱仪的真空系统得到简化,使质谱仪体积、重量、功耗等减小,同时也符合质谱仪器小型化的发展趋势。
[Abstract]:With the rapid development of mass spectrometry technology, mass spectrometer plays a more and more important role in life. Although most of the mass spectrometers have high performance, they must work under the condition of high vacuum, and the mass spectrometers are large in volume, heavy in weight, large in power consumption, inconvenient for carrying, and not convenient for real-time analysis on the spot. In this paper, a two-dimensional linear ion trap model is used to study the operating mode of charged ions in an ideal quadrupole field under low vacuum. Firstly, the simulation software SIMION used in this paper is briefly introduced, and the basic laws of charged ions in ideal quadrupole field under high vacuum condition are analyzed theoretically, including Matthew equation, ion motion stabilization region, ion duration frequency and so on. Then, two common elastic collision models between charged ions and inert gas molecules, Langevin model and Hardsphere model, are introduced. The stable region of ion motion at low vacuum is obtained by mathematical method. Finally, several standards for evaluating the performance of mass spectrometer are introduced, and three important steps and two modes of ion emission are introduced in detail, and the classical ion operation mode is given, which is modeled and simulated by SIMION. Considering the influence of different parameters such as cooling time, auxiliary AC signal amplitude and frequency on the resolution of mass spectrometer, the operating mode parameters of ion in low vacuum are obtained. On the premise of satisfying certain performance requirements, the research in this paper can simplify the vacuum system of mass spectrometer, reduce the volume, weight and power consumption of mass spectrometer, and also accord with the development trend of miniaturization of mass spectrometer.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH843

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