Structure Study of Proton Tautomers Based on Ion Mobility Mass Spectrometry and Ab Initio Molecular Dynamics Calculations

Investigating the structural characteristics of proton tautomers is of great significance for understanding organic reactions and biochemical processes. In this study, a method based on ion mobility mass spectrometry combined with ab initio molecular dynamics calculations was proposed. The structures of proton tautomers were determined by comparing the experimental and theoretical collision -induced dissociation (CID) mass spectrograms of different proton tautomers. Ion mobility mass spectrometry was used to separate proton tautomerism produced during ionization. The CID mass spectra of each isomer could be obtained after mobility separation. The quantum chemical mass spectrometry (QCXMS) program based on ab initio molecular dynamics calculations was used to calculate the fragmentation process and obtain the theoretical CID mass spectra. The results of experiment and calculation showed that this method effectively solved the issue of difficult identification of proton tautomers. This method was also of great significance for the study of ionization mechanism and organic reaction process using mass spectrometry.