弯曲型离子迁移管的初步研究

项目名称： 弯曲型离子迁移管的初步研究

项目编号： No.21205067

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 分析化学

项目作者： 倪凯

作者单位： 清华大学

项目金额： 25万元

中文摘要： 微小型化是离子迁移谱（IMS）发展的必然趋势，其中迁移管的微型化是重点和热点。现有的线性IMS微小型化方案均简单地将原有结构等比例缩小，导致迁移管长度不可避免地缩短，分辨率降低。虽然缩短离子门开启时间可以提高分辨率，但副作用是离子通量减少，灵敏度降低。针对这一问题，我们提出将传统的直线型迁移管改为弯曲型迁移管，其基本原理是由于离子在大气压下的宏观迁移速度正比于管腔内的电场强度（大小和方向），因而迁移轨迹会顺着弯曲管腔中的电场线前进，以达到在较小空间内获得较长迁移距离的目的。利用SIMION进行的初步仿真证实了该方案是可行的。采用弯曲型迁移管后，在弯道处不同转弯半径离子的迁移距离不同，会造成谱线展宽，考虑采用具有两个反向弯道的S形结构来补偿这一差异。本项目将在理论建模、数值仿真和实验测试等方面对弯曲型迁移管的特性进行系统研究和优化设计，有望为线性IMS的微小型化探索出一套新的可行的解决方案。

中文关键词： 弯曲型迁移管；电场均匀性；分辨率；补偿；BN离子门

英文摘要： The miniaturization of ion mobility spectrometry (IMS) is becoming more and more important, of which the most crucial technology is the miniaturization of the drift tube. However, currently all the miniature IMS just simply scale down the size with the normal structure, including the straight drift tube. This causes the drift length to be inevitably shortened and the resolution is decreased. Although shortening the open time of the ion gate can help to increase the resolution, the side effect is that the total amount of ions entering the tube is also reduced and the sensitivity is decreased. We proposed a new structure with curved drift tube instead of normal straight one. The design is based on the fact that the drift speed of ions under atmosphere is proportional to the electric field intensity (amplitude and direction) in the drift tube, so the ions will drift along curved electric field lines, making it possible to implement long drift distance in a small area. Preliminary simulation results by SIMION proved the feasibility of this design. Further more, in this design, ions with different turning radius in the curved section will experience different drift length, causing the spectral line width to be expanded. An "S" type curved tube can be used to compensate the length difference. This work will make a res

英文关键词： curved drift tube；electric field uniformity；resolution；compensate；Bradbury-Nielsen gate