More fragmentation on the ion at m z 303 afforded many fragment ions together with the ion at m z 187 . These information suggested that CYA G1 is known as a GSH adduct of mono oxygenated CYA, corresponding to FLU G1 of FLU. This assignment was supported by the negative MS MS spectrum of CYA G1 , which showed an intense fragment ion at m z 306 corresponding towards the molecular ion ? of GSH. The PI directed constructive MS MS spectrum of FLU G2 showed an ion at m z 582, with merchandise ions at m z 507, 453, 436, 350, 307, and 144 . This component was subsequently confirmed as the N S glutathionyl adduct previously reported . The adduct CYA G2 showed an ion at m z 562 with item ions at m z 487, 433, 416, and 287 . This part was confirmed because the N S glutathionyl adduct of CYA corresponding to FLU G2. The part FLU G3 displayed a molecular ion of m z 598, suggesting that this component was a GSH conjugate of mono oxygenated FLU.
Fragmentation of FLU G3 molecular ions resulted in NL of 129 and 75, corresponding to elimination of your pyroglutamate and glycine of GSH, respectively . The ion at m z 323 was formed by means of cleavage of sulfur carbon bond in the glutathionyl moiety. More fragmentation from the ion at m z 323 irreversible MEK inhibitor afforded a variety of fragment ions together with an extreme ion at m z 257 , distinct from that of FLU G1 . The fragment ion at m z 277 was formed by means of reduction with the components of NO2, a prevalent fragmentation observed in MS spectra of FLU . Further reduction in the factors of isobutyl carbonyl moiety through the ion at m z 277 afforded the fragment ion at m z 207 .
These information advised that although the MS MS spectrum of FLU G3 was in essence identical to that of FLU G1, FLU G3 was a GSH conjugate with attachment in the glutathionyl moiety to the aromatic group, previously detected being a quaternary ammonium GSH conjugate of hydroxylated FLU . This structural assignment was even more supported by the detrimental MS Chlorogenic acid MS spectrum of FLU G3 , which showed two extreme fragment ions at m z 272 and 323. Most informative was the lack of a fragment at m z 306, which was a base peak from the detrimental MS MS spectrum of FLU G1 corresponding to your molecular ion ? of GSH. The lack with the ions at m z 306 and 289 was constant together with the presence of an aromatic thioether motif within the GSH adduct FLU G3 . Similarly, CYA G3 showed an ion at m z 578, with merchandise ions at m z 503, 449, 432, and 303 . Even further fragmentation on the ion at m z 303 afforded a few fragment ions at m z 233, 283, and 285 .
These information recommended that CYA G3 is a GSH adduct of mono oxygenated CYA, corresponding to FLU G3 of FLU. This assignment was supported through the detrimental MS MS spectrum of CYA G3 , which showed two extreme fragment ions at m z 272 and 303, but lack of the ion at m z 306, which was a base peak in the damaging MS MS spectrum of CYA G1 .