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Updated: Dec 20, 2025

Identification of Fatty Acids in Bacillus cereus
Published on: December 5, 2016
Identification of Polymethylene-Interrupted Polyunsaturated Fatty Acids (PMI-PUFA) by Solvent-Mediated Covalent
Dong Hao Wang1,2, Zhen Wang1,2, J Raven Cortright1
1Dell Pediatric Research Institute, Depts of Pediatrics, of Chemistry, and of Nutrition, University of Texas at Austin, 1400 Barbara Jordan Blvd, Austin, Texas 78723, United States.
Abstract:
Pine nuts and other edible gymnosperm seeds contain unusual, bioactive polymethylene-interrupted polyunsaturated fatty acids (PMI-PUFAs), a subset of nonmethylene-interrupted PUFA with (-CH2-) intervening between double bonds. Conventional methods for structure elucidation of PMI-PUFAs require special derivatization risking rearrangement artifacts. Here we introduce a facile solvent-mediated (SM) covalent adduct chemical ionization (CACI) system modified with a triple quadrupole MS, which distinguishes PMI-PUFAs from their analogues in direct methyl ester form. The prominent Δ5 desaturated PMI-PUFAs exhibit characteristic fragmentation at C6-7 to yield ω diagnostic ions and share their fragmentation pattern with normal methylene interrupted PUFAs for the α diagnostic ion. H• transfer upon CID dissociation of PMI-PUFAs was found to be dependent on the relative position of isolated lone double bonds and cleavage points. Ginkgo and five species of pine nuts were characterized for their unique Δ5 fatty acid profile, without the need for chemical standards.
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