Fundamental investigations on the effect of high effective ion temperatures on the ion mobility, cluster formation, dissociation and their dynamics as well as fragmentation by high-resolution, high kinetic energy Ion mobility spectrometry

• Applicant: Professor Dr.-Ing. Stefan Zimmermann
• Subject Area: Measurement Systems
• Term: from 2016 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 318063177

This project with its fundamental questions on the effect of high effective ion temperatures on the ion mobility, cluster formation, dissociation and their dynamics as well as fragmentation is intended as a consequent continuation of the Project (sign removed). At the same time, the requested continuation is an excellent complement to the ongoing Project(sign removed)on ultra-high resolution ion mobility spectrometry for the detection of even smallest differences in ion mobility. However, due to the completely different design of the ion mobility spectrometer in(sign removed), this is only possible for low reduced electric field strengths below 10 Td. Thus, the investigations with a high-energy ion mobility spectrometer (HiKE-IMS) planned in the continuation are not possible in(sign removed), which mainly concentrates on complementary investigations on monomers and dimers and in particular on the separation of isomers and enantiomers. In contrast, the focus of this continuation is on detailed experimental investigations on the effect of ion and drift gas molecular mass and effective ion temperature on the ion mobility, cluster formation, cluster dissociation and their dynamics as well as fragmentation, which are only possible with HiKE-IMS. In this context, the effect of absolute temperature and reduced electric field strength on the ion mobility at constant effective ion temperature will be also investigated. The fundamental question is whether different ion mobilities exist despite constant effective ion temperature. Furthermore, the ion mobility of different ions as a function of the reduced electric field strength at constant absolute temperature will be directly measured, which is also only possible with HiKE-IMS. These so-called alpha functions are then to be compared with the alpha functions calculated from the measurement data of a Field Asymmetric Ion Mobility Spectrometer (FAIMS) in order to investigate the dynamics of cluster transitions. For all planned experimental investigations, the required instrumentation will be developed in the continuation. Based on the findings of(sign removed), a new HiKE-IMS with a significantly higher resolving power up to 200 and a temperature stability up to 120 °C will be developed. This includes a new drift tube design, a new ion gating sequence and a controlled corona discharge source as well as the development of advanced electronics. In order to compare the alpha functions over a wide range of reduced electric field strengths up to 120 Td, the FAIMS from(sign removed)also requires significantly improved control electronics, which will be also developed.

• DFG Programme: Research Grants