Paternò–Büchi Reaction Mass Spectrometry Enables Positional Assignment of Polymethylene-Interrupted Double Bonds in Food-Derived Lipids

• DOI: 10.1021/acs.jafc.3c06366
• Publication Date: 2024-02-03T14:48:35Z
• Authors: Zhen Wang; Secilia Garza; Xu Li; Md Saydur Rahman; J. Thomas Brenna; Dong Hao Wang
• Keywords: Fragmentation

Fatty acids (FAs) containing polymethylene-interrupted (PMI) double bonds are a component of human foods; however, they present significant analytical challenge for de novo identification. Covalent adduct chemical ionization and ozone-induced dissociation mass spectrometry (MS) methods enable unambiguous assignment PMI-FA bond positions, no method has been reported with electrospray (ESI) platform using off-the-shelf systems. In the current work, we studied Paternò–Büchi (PB) fragmentation patterns triacylglycerol (TG) by analyzing several known food sources. PB-MS/MS MS3 enabled complete location assignments, including isolated in triacylglycerols. Sea urchin ("uni"), oyster, pine nut, ginkgo nut were characterized their signature PMI-FA, 20:2(5Z,11Z), 22:2(7Z, 15Z), 18:3(5Z,9Z,12Z), 20:3(5Z,11Z,14Z), respectively. Quantitative analyses relative abundance these led to results similar reference methods. 18:3(5Z,9Z,12Z) was enriched at sn-1/sn-3 position major TG.