非对称半圆弧电极线性离子阱的离子单向出射性能研究

Miniaturization of ion trap mass spectrometer has become one of current research focuses in the field of mass spectrometry. Limited by the structure of its key component—ion trap, the existing miniaturized ion trap mass spectrometer suffers from low ion detection efficiency, which leads to a decrease of sensitivity. To solve the problem, this project develops an asymmetric structure HreLIT, which would significantly improve ion detection efficiency, through optimization of its geometrical structure and internal high-order electric field distribution. The main contents of this project include: the impact of geometrical parameter of asymmetric HreLIT on its internal electric field distribution; simulation of ion trajectory and performance evaluation of ion direction ejection in odd high-order electric fields; analysis and evaluation of mass resolution of asymmetric HreLIT under different high-order electric field distributions; comprehensive performance (including ion direction ejection efficiency and mass resolution) test of asymmetric HreLIT experimentally by constructing asymmetric HreLIT mass spectrometer platform. Successful implementation of this project would significantly improve the sensitivity of miniaturized ion trap mass spectrometer, as well as lower its detection limit.

离子阱质谱仪的小型化研究是当前质谱学领域的研究热点之一。受限于其核心部件离子阱的结构，当前的小型化离子阱质谱仪存在离子探测效率不高的缺陷，从而制约了仪器的检测灵敏度。为弥补上述不足，本项目提出了一种非对称式结构的半圆弧电极线性离子阱，通过对其电极几何结构进行优化设计，配置合理的内部高阶混合电场成分，以提高离子单向出射效率，进而实现大幅提高离子探测效率的目的。本项目的主要研究内容包括：非对称式半圆弧电极线性离子阱的几何结构对内部高阶电场分布的影响研究；奇次高阶混合电场下离子运动轨迹模拟及其离子单向出射性能研究；不同高阶混合电场分布对离子阱的质量分辨率的影响研究；非对称式半圆弧电极线性离子阱质谱仪器实验平台搭建及其综合分析性能评估。本项目若成功实施，将可大幅提高小型化离子阱质谱仪的检测灵敏度,并降低其探测下限。

为解决小型化离子阱质谱仪存在离子探测效率不高的问题，本项目提出了一种非对称式结构的半圆弧电极线性离子阱，通过对其电极几何结构进行优化设计，配置合理的内部高阶混合电场，以提高离子单向出射效率，进而实现大幅提高离子探测效率的目的。本项目主要研究了非对称电极拉伸和非对称电极旋转结构下，线形离子阱的离子单向出射效率和质量分辨率。经过几何参数优化，非对称半圆弧电极的离子单向出射效率达到90%，同时，其质量分辨率达到2400（FWHM）。本项目的研究成果可应用到小型化质谱仪的研发中，可大幅提高小型化离子阱质谱仪的检测灵敏度,并降低其探测下限。