Characterization of epoxy carotenoids by fast atom bombardment collision‐induced dissociation MS/MS

Abstract

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.

Simultaneous HPLC‐DAD‐MS (ESI+) determination of structural and geometrical isomers of carotenoids in mature grapes

“…8). They are characterized by the major product ions m / z 583.5 [M + H −18] + (elimination of water) and m / z 221.1, resulting from the cleavage of C10–C11 bond in the polyene chain, from the epoxy end group 56, 57. The 5,6‐epoxy xanthophyll, lutein‐5,6‐epoxide (peak 5, Fig.…”

HPLC‐PAD‐atmospheric pressure chemical ionization‐MS metabolite profiling of cytotoxic carotenoids from the echinoderm Marthasterias glacialis (spiny sea‐star)

“…Sci. 2010, 33, 2250-2257 Other observed ions are those resulting from the loss of fragments 56 u and/or 56118 u and 80118 u (Table 1), typical of the fragmentation of this class of compounds [12,13].…”

Identification of carotenoids using mass spectrometry

“…In addition to the fragment indicated above, ions at m / z 352 and 181 indicate that the epoxide is located in a ring with a hydroxyl substituent. These ions correspond to cleavages between carbons 12′ and 13′, and 8 and 9 of the polyene chain respectively (Azevedo‐Meleiro & Rodriguez‐Amaya, ; Maoka et al, ; Meléndez‐Martínez et al, ). These ions were observed using EI and FAB.…”