Investigation of the anaesthetic isoflurane fragmentation induced by electron impact

Abstract Isoflurane is a halogenated anaesthetic gas adopted in modern clinical practice due its efficacy and safety profile. However, its atmospheric persistence contributes to global warming potential that influences its overall environmental burden. In this study, we employed a crossed electron-molecular beam technique to investigate dissociative electron attachment (DEA) processes in order to investigate isoflurane fragmentation induced by electron impact. The DEA process results in the formation of twelve anionic fragments, including halogenated anions (Cl − and F − ), complex fluoro-chloro containing species ( e.g., [C 2 F 3 Cl] − , [C 2 HFCl] − ), and oxygen-containing anions such as [CHF 2 O] − and [CFO] − . The most intense signal corresponds to Cl − , which exhibits a sharp resonance near 0.1 eV, can be attributed to a shape resonance or due high dipole moment of isoflurane (2.47 D) to a vibrational Feshbach resonance (VFR). In contrast, F − formation is observed in a high-energy domain (4–7 eV) and proceeds via core-excited resonance. Remarkably, the [FHF] − anion was detected with unexpectedly high intensity at low energies, suggesting the occurrence of complex multi-bond dissociation and electron-induced molecular rearrangement. These findings provide important insights into the electron-induced chemistry of halogenated anaesthetics. Graphic abstract