Investigation of surface-induced dissociation mechanisms of liquid droplets from electrospray ionisation in transfer stages of mass spectrometers

• Applicant: Dr. Walter Wißdorf
• Subject Area: Analytical Chemistry ; Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 558979381

Mass spectrometry (MS) with electrospray-ionization (ESI) is among the most important methods in modern analytical chemistry. A liquid solution of the analyzed substance, the analyte, is sprayed in a strong electric field which forms charged liquid droplets. Experimental evidence suggests that those droplets are aspirated into the vacuum system of MS instruments, contrary to assumptions widely held in the research community. Here, collisions between droplets and surfaces are taking place, which induce sudden fragmentation of the droplets. Our experimental observations are strongly suggesting that this process is taking place in the instruments. Such surface collisions between highly charged droplets of different composition and surfaces are a very complex process. There is no molecular model of such collision processes. The proposed project plans to study such collision events with molecular dynamic (MD) simulations in detail. The results allow to draw conclusions for the relevance of surface collisions of aspirated charged droplets for the contamination, the operational conditions and the analytical performance of common ESI-MS systems.

• DFG Programme: Research Grants