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Regioisomers of octanoic acid‐containing structured triacylglycerols analyzed by tandem mass spectrometry using ammonia negative ion chemical ionization
Author(s) -
Kurvinen J. P.,
Mu H.,
Kallio H.,
Xu X.,
Høy C. E.
Publication year - 2001
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-001-0855-9
Subject(s) - structural isomer , chemistry , tandem mass spectrometry , mass spectrometry , atmospheric pressure chemical ionization , chemical ionization , ion , fragmentation (computing) , dissociation (chemistry) , dart ion source , deprotonation , ionization , collision induced dissociation , analytical chemistry (journal) , chromatography , organic chemistry , electron ionization , computer science , operating system
Tandem mass spectrometry based on ammonia negative ion chemical ionization and sample introduction via direct exposure probe was applied to analysis of regioisomeric structures of octanoic acid containing structured triacylglycerols (TAG) of type MML, MLM, MLL, and LML (M, medium‐chain fatty acid; L, long‐chain fatty acid). Collision‐induced dissociation of deprotonated parent TAG with argon was used to produce daughter ion spectra with appropriate fragmentation patterns for structure determination. Fatty acids constituting the TAG molecule were identified according to [RCO 2 ] − ions in the daughter ion spectra. With the standard curve for ratios of [M‐H‐RCO 2 H‐100] − ions corresponding to each [RCO 2 ] − ion, determined with known mixtures of sn ‐1/3 and sn ‐2 regioisomers of structured TAG, it was possible to determine the proportions of different regioisomers in unknown samples. The method enabled quantification of MML‐ and MLM‐type structured TAG. In the case of MLL‐ and LML‐type TAG, it was possible to determine the most abundant regioisomer in the unknown mixture and estimate the proportions of regioisomers when there were more than 50% MLL‐type isomers in the mixture.