Enhancing Separation and Constriction of Ion Mobility Distributions in Drift Tubes at Atmospheric Pressure Using Varying Fields
Enhancing Separation and Constriction of Ion Mobility Distributions in Drift Tubes at Atmospheric Pressure Using Varying Fields
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DOI：
10.1021/acs.analchem.2c00467
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发表时间：
2022-04-12
影响因子：
7.4
通讯作者：
Larriba-Andaluz, Carlos
中科院分区：
文献类型：
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作者：
Chen, Xi;Latif, Mohsen;Larriba-Andaluz, Carlos
此前已证明，线性减小的电场对于变场漂移管（VFDT）系统中离子的扩散校正是有效的，由于其能够在飞行中缩小分布，因此与传统漂移管相比，具有更高的分辨率。然而，理论预测的分辨率的VFDT是远远高于实验观察到的。这种差异背后的原因已被确定为理论计算的分辨率（空间）和实验分辨率（时间）之间的差异。为了在实验上匹配高的空间分辨能力，在适当调整的时间处的次级高压脉冲（HVP）用于为离子提供足够的动量以增加它们的漂移速度，从而增加它们的时间分辨能力。一系列系统的数值模拟和实验测试已经被设计来证实我们的理论研究结果。HVP-VFDT大气压便携式系统将分辨率从常规漂移管的最大预期60-80提高到250，长度仅为21 cm，电压为7 kV，这是前所未有的成就。
A linearly decreasing electric field has been previously proven to be effective for diffusional correction of ions in a varying field drift tube (VFDT) system, leading to higher resolving powers compared to a conventional drift tube due to its capacity to narrow distributions midflight. However, the theoretical predictions in resolving power of the VFDT were much higher than what was observed experimentally. The reason behind this discrepancy has been identified as the difference between the theoretically calculated resolving power (spatial) and the experimental one (time). To match the high spatial resolving power experimentally, a secondary high voltage pulse (HVP) at a properly adjusted time is used to provide the ions with enough momentum to increase their drift velocity and hence their time-resolving power. A series of systematic numerical simulations and experimental tests have been designed to corroborate our theoretical findings. The HVP-VFDT atmospheric pressure portable system improves the resolving power from the maximum expected of 60-80 for a regular drift tube to 250 in just 21 cm in length and 7kV, an unprecedent accomplishment.