title: Synthesis and tandem mass spectrometry of chlorinated triacylglycerols.
abstract: The incorporation of 9,10-dichlorooctadecanoyl groups using enzyme-catalyzed acylation and protecting group strategies yielded specific regioisomers of di- and tetrachlorinated triacylglycerols. Hexachloro- and hexabromotriacylglycerols were synthesized by addition of chlorine or bromine to tri-(cis-9-octadecenoyl)glycerol. Upon electrospray ionization and tandem mass spectrometry, the sodium adduct ions of all compounds containing a 9,10-dichlorooctadecanoyl group readily lost two molecules of HCl when subjected to collision-induced dissociation. A mechanism describing sequential HCl losses and the formation of a conjugated diene is proposed for the loss of both vicinal chlorine atoms from an alkyl chain. This characteristic fragmentation behavior and the availability of characterized standards will facilitate the development of quantitative analytical methods for the determination of chlorinated triacylglycerols in lipid mixtures isolated from marine and other biological sources.
authors.affiliation: Department of Chemistry, Dalhousie University, 6274 Coburg Road, P.O. Box 15000, Halifax, Nova Scotia, Canada B3H 4R2.
authors.forename: Abir M
authors.initials: AM
authors.lastname: Lefsay
authors.forename: Robert D
authors.initials: RD
authors.lastname: Guy
authors.forename: Amares
authors.initials: A
authors.lastname: Chatt
authors.forename: Robert L
authors.initials: RL
authors.lastname: White
mesh_terms: D001234:Aspergillus niger / Q000201:enzymology; D002175:Candida / Q000201:enzymology; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D054879:Halogenation; D008049:Lipase / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D020103:Rhizomucor / Q000201:enzymology; D053719:Tandem Mass Spectrometry; D014280:Triglycerides / Q000096:biosynthesis / Q000737:chemistry*
chemical_list: D004800:Enzymes, Immobilized; D005656:Fungal Proteins; D011994:Recombinant Proteins; D014280:Triglycerides; D008049:Lipase
keywords: 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride; 4-dimethylaminopyridine; CID; DMAP; EDCl; ESI; Fragmentation mechanism; GC; LC-MS/MS; Mass spectrometry; Organochlorine; Triacylglycerol; collision-induced dissociation; electrospray ionization; gas chromatography; liquid chromatography–tandem mass spectrometry