Fundamental investigations of ion mobility and separation of isomers by high resolution ion mobility spectrometry

提出的研究项目的主要目标是开发一种紧凑的高分辨率离子迁移谱仪（IMS），其分辨率为rbbb300，检测限低至pt水平，快速响应时间不到一秒，而不同的非放射性离子源可以根据应用轻松耦合到IMS。主要的技术挑战是设计这样一个紧凑的IMS，满足上面提到的所有分析需求，以及开发操作系统所需的复杂电子设备。这包括开发一种低噪声，高增益放大器，在150 kHz时具有1 GV/ a，并且可以根据实现的分辨率轻松调整带宽，用于操作离子快门的快速高压开关和用于直接低功耗漂移环电极的紧凑高压级联电路。为了优化IMS设计，需要进行详细的实验表征。此外，分析和数值模型考虑所有相关的影响分析性能将开发和实验验证。特别地，离子在IMS内部从电离区到探测器板的传输将被数值模拟。然而，为了进行可行的模拟，必须仔细考虑主要由离子百叶窗和移动离子云引起的瞬态电场不均匀性、金属表面离子放电效应、离子和中性离子的扩散和对流输运现象以及不同离子源的电离特性。此外，在通过百叶窗注入离子的瞬间，将测量不同离子源在电离区域内产生的离子密度和离子分布，并将其作为数值模拟的可行初始条件。本课题主要研究非放射性电子发射器、弱x射线源和离子产生的光离源。经过连续的优化循环，实验验证的理论模型描述了对分析性能的所有相关影响，以及具有交换离子源的紧凑高分辨率IMS将在项目结束时可用。一个可能的项目扩展将集中于面向应用的系统优化，重点是呼吸分析和生物过程监测。此外，纳米电喷雾电离源将与IMS耦合，用于液体的快速分析。

The main objective of the proposed research project is the development of a compact high-resolution ion mobility spectrometer (IMS) with a resolving power of R > 300, detection limits down to ppt-levels and fast response times of less than a second while different non-radioactive ion sources can be easily coupled to the IMS depending on the application. The main technical challenges are designing such a compact IMS that meets all the analytical requirements mentioned above and the development of complex electronics required for operating the system. This includes the development of a low-noise, high-gain amplifier with 1 GV/A at 150 kHz and the possibility to easily adjust the bandwidth with respect to the achieved resolving power, fast high-voltage switches for operating the ion shutter and a compact high-voltage cascade circuit for a direct low-power supply of the drift ring electrodes. In order to optimize the IMS design a detailed experimental characterization is needed. Furthermore, analytical and numerical models considering all relevant effects on the analytical performance will be developed and experimentally validated. In particular, the ion transport inside the IMS from the ionization region to the detector plate will be numerically simulated. However, for feasible simulations the transient electrical field inhomogeneities mainly caused by the ion shutter and moving ion clouds, ion discharge effects at metallic surfaces, diffusion and convective transport phenomena of ions and neutrals as well as the ionization properties of different ion sources have to be carefully considered. In addition, the ion density and ion distribution generated inside the ionization region by different ion sources will be measured at the moment of ion injection through the shutter and used as feasible initial conditions for the numerical simulations. This research project concentrates on a non-radioactive electron emitter, a weak x-ray source and a photoionization source for ion generation. After successive optimization cycles both an experimentally validated theoretical model describing all relevant effects on the analytical performance and a compact high-resolution IMS with exchangeable ion sources will be available at the end of the project. A possible project extension would concentrate on application-oriented system optimization with a focus on breath analysis and bioprocess monitoring. Furthermore, a nano-electrospray ionization source will be coupled to the IMS for fast analysis of liquids.