Collision-induced isomerization in tandem mass spectrometry

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K05138
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 34020:Analytical chemistry-related
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Nakamura Takemichi 国立研究開発法人理化学研究所, 環境資源科学研究センター, 特別嘱託研究員 (10360611)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: tandem mass spectrometry / fragmentation pathway / isomerization / ion structure / ion mobility / collisional excitation / energetics

Outline of Final Research Achievements

Fragmentation in collision-induced dissociation (CID) tandem mass spectrometry is widely used for structural characterization beyond the molecular formula assignment of soft-ionized analytes including isomeric small molecules. However, it turned out the spectral information may be degraded due to isomerization prior to the fragmentation. Collision-induced isomerization (CII), the isomerization process associated with CID was studied by using energy-resolved tandem mass spectrometry (ER-MS/MS), ion mobility spectrometry-tandem mass spectrometry (IMS/MS/MS), and computational chemistry. CII does occur in an energy dependent manner as ER-IMS/MS/MS experiments showed that relative abundance of the isomeric ion structures depends on the degree of collisional excitation prior to the mobility separation.

Free Research Field

mass spectrometry

Academic Significance and Societal Importance of the Research Achievements

本研究で得られた知見である，微量有機分子のタンデム質量分析において汎用される CID の条件下で前駆イオンの骨格転位を伴う異性化が起こりうる，という事実は，マススペクトルデータを用いて構造解析を試みようとする有機化学者にとって「不都合な真実」である．しかし，衝突エネルギー依存的な骨格転位の頻度や前駆イオン構造要素との関係性が解明されていくことにより既存手法の限界が明確化する同時に，構造解析や異性体識別の可否などを適切に評価することが可能となり，分析の信頼性向上と新たな解析法開発の指針へと繋がっていくことが期待される．