The Characterization and Metastable Decomposition of Isobaric Ions from Several Compounds

Abstract

The characterization and metastable decomposition of isobaric ions from several compounds are described by using high-resolution mass spectrometry (HR-MS) and mass-analyzed ion kinetic energy (MIKE) spectrometry. The m/z 45 ions from 2-methoxyethylamine, CH₃OCH₂CH₂NH₂ (1) consists of two isobaric ions, methoxymethyl ion, CH₃OCH₂⁺, and C₂H₇N⁺ ion. The former decomposes into the m/z 29 ion by losing CH₄ in metastable time window. Although the latter decomposes into the m/z 30 and 18 ions, its structure could not be confirmed in this study. The m/z 69 ions generated from methyl trifluoroacetoacetate, CF₃COCH₂COOCH₃ (2) and 1,1,1,5,5,5-hexafluoro-2,4-pentanedione, CF₃COCH₂COCF₃ (3) also consists of two isobaric ions, trifluoromethyl ion, CF₃⁺, and protonated carbon suboxide, OCCHCO⁺. The former does not decompose into any ions in the metastable time window. On the other hand, the latter decomposes into m/z 41 ion by losing CO.