Ion collision crosssection measurements in quadrupole ion traps using a time-frequency analysis method.
Ion collision crosssection measurements in quadrupole ion traps using a time-frequency analysis method.
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DOI：
10.1039/c4an01216j
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发表时间：
2014-10
期刊：
影响因子：
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通讯作者：
Muyi He;Dan Guo;Yu Chen;Xingchuang Xiong;Xiang Fang;Wei Xu
中科院分区：
文献类型：
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作者：
Muyi He;Dan Guo;Yu Chen;Xingchuang Xiong;Xiang Fang;Wei Xu
本研究提出了一种通过对四极离子阱中离子轨迹的时频分析来测量离子碰撞截面（CCSs）的方法。设计并模拟了一种具有高次电场的线性离子阱。随着高阶电场和离子中性碰撞的存在，离子在四极离子阱内的长期运动频率将是离子运动幅度的函数，从而是时间和离子CCS的函数。然后建立了离子CCS和离子运动频率相对于时间的直接关系，这可以通过离子轨迹（或离子运动诱导的图像电流）的时频分析获得。为了证实这一理论，我们进行了真实的离子轨迹模拟，根据模拟的离子轨迹计算了缓激肽、血管紧张素I和血管紧张素II以及泛素的CCSs。作为一个例子，在模拟中也证明了异构体泛素离子的分化。
In this study, a method for measuring ion collision crosssections (CCSs) was proposed through time-frequency analysis of ion trajectories in quadrupole ion traps. A linear ion trap with added high-order electric fields was designed and simulated. With the presence of high-order electric fields and ion-neutral collisions, ion secular motion frequency within the quadrupole ion trap will be a function of ion motion amplitude, thus a function of time and ion CCS. A direct relationship was then established between ion CCS and ion motion frequency with respect to time, which could be obtained through time-frequency analysis of ion trajectories (or ion motion induced image currents). To confirm the proposed theory, realistic ion trajectory simulations were performed, where the CCSs of bradykinin, angiotensin I and II, and ubiquitin ions were calculated from simulated ion trajectories. As an example, differentiation of isomeric ubiquitin ions was also demonstrated in the simulations.