Fig. 4.
Fragmentation pattern of sterol glucosides and acylated sterol glucosides. A: Q-TOF MS/MS spectra of different SGs. Collision induced dissociation of the ammonium adduct of SGs produces a sterol fragment FS. The spectrum of the saturated stigmastanol-Glc (used as the internal standard) reveals a peak of lower intensity corresponding to the sterol fragment Fs and the presence of additional peaks. B: Q-TOF MS/MS spectra of ASGs. Note that fragmentation of ASGs with unsaturated sterol moieties leads to the release of the sterol cation FS. Fragmentation of ASGs with saturated sterol moieties (16:0-Glc-stigmastanol, internal standard) leads to the accumulation of a peak at 401.2898, corresponding to the 16:0-Glc cation.