三角形电极离子阱的理论模拟及性能优化

作为一种新型结构的线性离子阱,三角形电极离子阱( TeLIT)具有简单的电极结构与良好的分析性能。为进一步提高TeLIT的质谱性能,本研究考察了TeLIT的性能与电极结构的关系。利用模拟软件SIMI-ON和AXSIM分析TeLIT场半径比与其内部电场分布的关系,并模拟离子运动轨迹,得出模拟离子质谱峰。理论模拟结果表明：优化场半径比可以改善内部电场分布,并能显著提高TeLIT的质量分辨率。最终模拟得出场半径比rx/ry=5.75：5时为最优结构,在该结构下,m/z为1892 Th的离子在扫描速率为1500 Th/s时,质量分辨率可以达到8287；扫描速率降为300 Th/s时,最高质量分辨率可达23000。

Optimization of Linear Ion Trap Mass Analyzer with Triangular Electrodes by Simulation

As a novel linear ion trap, the triangular-electrode linear ion trap ( TeLIT) has simple structure and good performance. The relationship between its geometry and performance was investigated. Ion trajectories and mass peaks of TeLIT with different ratios of field radius ( rx/ry ) were analyzed by using simulation software SIMION and AXSIM. It was shown that the performance of the TeLIT could be enhanced by optimizing rx/ry which would improve internal electric fields distribution. The optimum mass resolution of 8387 was achieved for ions with m/z 1892 Th at rx/ry=5. 75/5 when scan rate was 1500 Th/s. When the scan rate was decreased to about 300 Th/s, the resolving power of the mass spectrum was in excess of 23000.