Guo Kaitai, Zheng Yang, Hu Haihong, Liang Jimin
School of Electronic Engineering, Xidian University, Xi'an, Shaanxi, China.
Front Chem. 2022 Sep 21;10:1004615. doi: 10.3389/fchem.2022.1004615. eCollection 2022.
Ion mobility spectrometer (IMS) is a powerful chemical composition analysis tool working at atmospheric pressure that can be used to separate complex samples and study molecular structures. Resolution is a key parameter for evaluating the performance of IMS. However, for the pulsed sampling technique used by drift tube IMS, there is an upper limit to the resolution due to the diffusion between ions and the drift gas. In this work, an inverse diffusion counterbalance method is proposed to break the resolution limit. The method is inspired by the stimulated emission depletion (STED). In optical microscopy systems, STED is used to break the optical diffraction limit by a ring of depleted light to counteract diffraction effects of the excited light. We modified this strategy and applied it to an IMS system for counteracting the diffusion effect of the pulsed ion packet. The method can increase the resolution up to 1.55 times through theoretical analysis, and the improvement is verified by simulations. The simulation results find that the initial width of the ion packet has an influence on the effectiveness of the method, and the narrower the initial width, the better the effect. The proposed inverse counterbalance strategy may also be applied to other spectral analysis instruments to break the resolution limit.
离子迁移谱仪（IMS）是一种在大气压下工作的强大的化学成分分析工具，可用于分离复杂样品并研究分子结构。分辨率是评估IMS性能的关键参数。然而，对于漂移管IMS所采用的脉冲采样技术，由于离子与漂移气体之间的扩散，分辨率存在上限。在这项工作中，提出了一种逆扩散平衡方法来突破分辨率限制。该方法的灵感来自受激辐射损耗（STED）。在光学显微镜系统中，STED通过一圈耗尽光来抵消激发光的衍射效应，从而突破光学衍射极限。我们对这一策略进行了改进，并将其应用于IMS系统，以抵消脉冲离子包的扩散效应。通过理论分析，该方法可将分辨率提高至1.55倍，且通过模拟验证了这种改进。模拟结果表明，离子包的初始宽度对该方法的有效性有影响，初始宽度越窄，效果越好。所提出的逆平衡策略也可能应用于其他光谱分析仪器以突破分辨率限制。
