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A new sample preparation method for matrix-assisted laser desorption/ionization (MALDI) analysis of native rough-type lipopolysaccharides (R-type LPSs) is presented. In our MALDI mass spectra, besides the [MH]− ions, abundant ions originating from the cleavage between the 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo) unit and the lipid A moiety are always present, giving important pieces of information about the structure of the molecules analyzed. Remarkably, in most cases, the comparison of the MALDI mass spectra of the intact R-type LPS with the O-deacylated one allowed us to obtain the structure of the lipid A moiety. Copyright © 2005 John Wiley & Sons, Ltd.

Poly(β-hydroxybutyrate-co-β-hydroxyvalerate) of microbial origin has been analyzed by matrix-assisted laser desorption/ionization (MALDI) in a time-of-flight mass spectrometer, after partial methanolysis, using two different instruments, Our results show that the mass spectral intensities recorded in the MALDI mode correlate with previously reported fast-atom bombardment and direct chemical ionization data. MALDI compares favourably with these other two techniques in that it is more suitable to the analysis of complex mixtures and of higher molecular masses.

The use of matrix-assisted laser desorption/ionization mass spectrometry for the determination of the molecular weight distribution of cyclic ? (1-2) glucans is reported here. Quantitative response is demonstrated by the use of different instruments and by comparison with high-performance liquid chromatography/refractive index detection analysis.

We report here a study by negative-ion fast-atom bombardment (FAB) mass spectromatry of branched oligosacharides containing a 3-O glyesidie linkage. Our result show that discrimination of the monosaccharide unit linked in the 3-O position is made possible by the analysis of the negative-ion FAB mass spectra. In the mass spectrum of A-trisaccharide (α-Fuc1-2-(α-GalNAc1-3)-Gal) the peak at m/z 307 can be explained as elimination of a neutral molecule of GalNAc(221 u) from the molecular ion. Also in the mass spectrum of 3-fucosyllaactose (α-Fuc1-3-(β-Gall-4)-Glc) an intense peak at m/z 323, corresponding to the elimination of the fucose linked at the 3 position of glucose is present. To investigate further the fragmentations of the 3-O-linked sugars, the negative-ion FAB mass spectra of disaccharides have also been studied.