FAB MS & NMR ANALYSIS OF GANGLIOSIDE

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1H-NMR analyses were performed on a Bruker AMX-500 spectrometer. The samples were deuterium-exchanged by lyophilization from D2O and dissolved in 0.5 mL DMSO-d6/D2O 982. The 1D 1H-NMR spectra were obtained at 308(K (35(C) at 500 MHz, using presaturation of the residual HOD signal. Chemical shifts were measured relative to the residual protonated DMSO-d6 at 2.503 ppm (measured indirectly relative to TMS=0.0ppm). The positive ion mode FAB mass spectra were obtained using the first two sectors of a JEOL SX/SX102A tandem four-sector mass spectrometer operated at an acceleration potential of 10 kV. Linear upward scanning was employed such that the mass range from m/z 100 to 2500 is scanned in 1 minute. Application of both techniques confirmed the identities of two of the gangliosides with respect to their glycan structures, the molecular weight distribution and type of ceramides present, and their overall purity. The third ganglioside sample was found to be a very im pure preparation, as indicated by both NMR and FAB-MS analysis.