Tian Yuan, Decker Trevor K, McClellan Joshua S, Wu Qinghao, De la Cruz Abraham, Hawkins Aaron R, Austin Daniel E
Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84602, USA.
Department of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou, 450001, Henan, People's Republic of China.
J Am Soc Mass Spectrom. 2018 Jul;29(7):1376-1385. doi: 10.1007/s13361-018-1942-x. Epub 2018 Apr 5.
The performance of miniaturized ion trap mass analyzers is limited, in part, by the accuracy with which electrodes can be fabricated and positioned relative to each other. Alignment of plates in a two-plate planar LIT is ideal to characterize misalignment effects, as it represents the simplest possible case, having only six degrees of freedom (DOF) (three translational and three rotational). High-precision motorized actuators were used to vary the alignment between the two ion trap plates in five DOFs-x, y, z, pitch, and yaw. A comparison between the experiment and previous simulations shows reasonable agreement. Pitch, or the degree to which the plates are parallel along the axial direction, has the largest and sharpest impact to resolving power, with resolving power dropping noticeably with pitch misalignment of a fraction of a degree. Lateral displacement (x) and yaw (rotation of one plate, but plates remain parallel) both have a strong impact on ion ejection efficiency, but little effect on resolving power. The effects of plate spacing (y-displacement) on both resolving power and ion ejection efficiency are attributable to higher-order terms in the trapping field. Varying the DC (axial) trapping potential can elucidate the effects where more misalignments in more than one DOF affect performance. Implications of these results for miniaturized ion traps are discussed. Graphical Abstract ᅟ.
小型离子阱质量分析仪的性能在一定程度上受到电极制造精度以及彼此相对位置精度的限制。两板平面线性离子阱中极板的对准对于表征失准效应非常理想，因为它代表了最简单的情况，仅有六个自由度（DOF）（三个平移自由度和三个旋转自由度）。使用高精度电动致动器在五个自由度（x、y、z、俯仰和偏航）上改变两个离子阱极板之间的对准。实验与先前模拟之间的比较显示出合理的一致性。俯仰，即极板沿轴向方向的平行程度，对分辨率的影响最大且最显著，当俯仰失准仅为几分之一度时，分辨率就会明显下降。横向位移（x）和偏航（一个极板旋转，但极板仍保持平行）对离子喷射效率都有很大影响，但对分辨率影响很小。极板间距（y 位移）对分辨率和离子喷射效率的影响可归因于捕获场中的高阶项。改变直流（轴向）捕获电势可以阐明多个自由度中更多失准影响性能的情况。讨论了这些结果对小型离子阱的意义。图形摘要ᅟ。
