Characterization of epoxy carotenoids by fast atom bombardment collision-induced dissociation MS/MS.
The characterization and structure of epoxy carotenoids possessing 5,6-epoxy, 5,8-epoxy and 3,6-epoxy end groups conjugated to the polyene chain were investigated using high-energy fast atom bombardment collision-induced dissociation MS/MS methods. In addition to [M - 80](+*), a characteristic fragment ion of an epoxy carotenoid, product ions resulting from the cleavage of C-C bonds in the polyene chain from the epoxy end group, such as m/z 181 (b ion) and 121 (c ion), were detected. On the other hand, diagnostic ions of m/z 286 (e-H ion) and 312 (f-H ion) were observed, not in the 5,6-epoxy or 5,8-epoxy carotenoid but in the 3,6-epoxy carotenoid. These fragmentation patterns can be used to distinguish 3,6-epoxy carotenoids from 5,6-epoxy or 5,8-epoxy carotenoids. The structure of an epoxy carotenoid, 3,6-epoxy-5,6-dihydro-7',8'-didehydro-beta,beta-carotene-5,3'-diol (8), isolated from oyster, was characterized using FAB CID-MS/MS by comparing fragmentation patterns with those of related known compounds.
Maoka
Takashi
T
Research Institute for Production Development, Kyoto 606-0805, Japan.
Fujiwara
Yasuhiro
Y
Hashimoto
Keiji
K
Akimoto
Naoshige
N
D000818:Animals; D002338:Carotenoids / Q000737:chemistry* / Q000302:isolation & purification; D028464:Cucurbita; D004852:Epoxy Compounds / Q000737:chemistry / Q000302:isolation & purification; D015394:Molecular Structure; D010125:Ostreidae; D016339:Spectrometry, Mass, Fast Atom Bombardment / Q000379:methods*; D014561:Urochordata
D004852:Epoxy Compounds; D002338:Carotenoids