| Abstract: | The design of the new MKh 1310 mass spectrometer with double focusing permits the recording of the spectra of sparingly volatile natural compounds with molecular weights of up to 1700 and, in particular, the permethylates and peracetates of spirostanol and furostanol saponins. The results are given of an investigation of the mass spectra of five spirostanol tetraosides in the form of their permethylates. The spectra contain the peaks of the molecular ions and of the products of their decomposition at the glycosidic bonds. The most important feature of the spectra is the fragmentation of the skeletons of the terminal saccharide residues starting directly from M+ in directions close to the directions of decomposition of the nonreducing unit of permethylates of oligosaccharides. The origin of the ions (M -191)+, (M - 175)+, (M - 162)+, (M - 147)+, (M - 131)+, (M - 118)+, and (M - 102)+ arising this way have been confirmed by measurements of their elementary compositions. |
