Ion trajectory simulations of a conical octopole ion guide and its comparison with a parallel one in chemical ionization mass spectrometric applications
Ion trajectory simulations of a conical octopole ion guide and its comparison with a parallel one in chemical ionization mass spectrometric applications
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化学电离质谱应用中锥形八极离子导向器的离子轨迹模拟及其与平行离子导向器的比较
DOI：
10.1002/rcm.8129
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发表时间：
2018
影响因子：
2
通讯作者：
Zhao Jun
中科院分区：
文献类型：
--
作者：
Shao Qiduo;Zhao Jun
聚焦和透射是质谱应用中离子输运的重要特征。离子导流装置是质谱仪的重要组成部分，特别是当化学电离被使用时。我们提出了一种锥形八爪形离子导轨，并将其与平行的离子导轨进行了比较，通过离子导轨和四极杆质量分析仪来模拟离子轨迹。方法利用SIMION 8.0软件进行轨迹模拟，通过将八爪离子导轨与质谱仪中的四极杆质谱仪结合使用，对锥形和平行八爪离子导轨的性能进行评估，并对整体离子传输进行评估。通过仿真，优化了控制弱键簇离子聚焦和输运的参数，包括直流偏置电压、正弦波的频率和振幅。结果离子轨迹模拟结果表明，锥形八爪形离子导轨的离子束可以在直径为10 mm至2 mm的范围内高度聚焦。传输效率取决于离子的质量、施加在章鱼上的射频波形的频率和幅度。模拟的锥形离子波导的整体传输效率与先前报道的低质量区域校准实验中观察到的灵敏度一致，但远高于高质量区域（即质量大于400 amu）。结论模拟结果表明，锥形八爪形离子导向器能够高效地通过差抽真空腔输送高聚焦离子。然而，在假设八爪离子导轨沿轴向呈指数压力梯度的情况下，与四极杆质谱仪结合使用时，锥形八爪离子导轨的整体传输效率普遍低于平行四极杆质量分析仪。
RationaleFocusing and transmission are important characteristics of ion transportation in mass spectrometric applications. An ion guide device is an essential component in a mass spectrometer, especially when chemical ionization is employed. We present a conical octopole ion guide and its comparison with a parallel counterpart for simulating the ion trajectories through the ion guide and the quadrupole mass analyzer.MethodsIon trajectory simulations using SIMION 8.0 were performed to evaluate the performance of both conical and parallel octopole ion guides and the overall ion transmission through combining the octopole ion guide and the quadrupole mass analyzer in the mass spectrometer. Through the simulations, parameters that control the ion guide were optimized for the focus and transport of weakly bonded cluster ions, including the DC bias voltage, the frequency and the amplitude of the sine wave applied to the guide.ResultsThe results from ion trajectory simulations showed that the ion beam can be highly focused from initially 10 mm down to 2 mm in diameter for the conical octopole ion guide. The transmission efficiencies are dependent on the mass of the ion, the frequency and amplitude of the radiofrequency waveform applied to the octopoles. The simulated overall transmission efficiencies of the conical ion guide are consistent with the observed sensitivities from the previously reported calibration experiments in the low‐mass region but are much higher than those in the high‐mass region (i.e., masses greater than 400 amu).ConclusionsThe simulations showed that the conical octopole ion guide can efficiently transport ions with high focusing through differentially pumped vacuum chambers. However, the overall transmission efficiencies of the conical octopole ion guide are in general lower than the parallel one when combined with the quadrupole mass analyzer based on the assumed exponential pressure gradient along the axial of the octopole ion guide.