Fig. 1.
(a) ESI-MS and (b) ESI-MS/MS spectra of the toxin from B. cereus F-5881. M + NH4]+ is ammonium adduct ion and M + H]+ is protonated molecular ion of cereulide. Two peaks were obtained m/z 1170·70 and 1191·91 by ESI-MS, representing the ammonium and potassium adducts of cereulide, respectively. The ESI-MS/MS spectrum of the precursor ion m/z 1170·70 shows that first fragment lost is ammonia and the result is a protonated molecular ion of m/Z 1153·83.