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Mass spectra of oligosaccharides

The use of mass spectrometry to characterize oligosaccharides is not new. Indeed, GC/MS has been used for several decades to identify monosaccharides or very small oligosaccharides. The use of GC/MS needs the prior derivatization of these molecules by methylation, acetylation or trimethylsilylation. [Pg.358]

Today (2000), GC/MS is still the method of choice for the determination of the monosaccharide composition of oligosaccharides and is widely used. The analysis starts with the hydrolysis or alcoholysis of the oligosaccharide to monosaccharides, which after derivatization (mostly by trimethylsilylation) are analysed by GC/MS. [221] Monosaccharide identification is based on comparison of retention time and fragmentation pattern with references. [Pg.358]

Mass spectrometry analysis of oligosaccharides without hydrolysis has started with the FAB ionization technique and has developed with ESI and MALDI. Fast atom bombardment usually generates a weak signal, whereas ESI is not as efficient for native oligosaccharides as MALDI. Indeed, native oligosaccharides do not contain either acidic or basic groups, [Pg.358]

Whatever the ionization method used, the mass spectra of oligosaccharides analysed by ESI, MALDI or FAB display intense ions of the molecular species resulting from protonation (M -(- H)+ or cationization by an alkali metal ion (M + alkali metal) 1 in the positive ion mode or from deprotonation (M — II) in the negative ion mode. In ESI, multiply charged ions also are produced. [Pg.359]

Alkali metal adducts often are observed, and even in negative ion mode (M + Na — 2H) are often abundant for monocharged ions. If they can be avoided, not only does the signal increase because it is not divided any more over several species but also better MS/MS spectra can be obtained. To eliminate these adducts, glassware should not be used during sample work-up. Then, addition of acid or, better still, ammonium acetate allows their interference to be reduced further. However, often alkali metal salts are added at low concentrations to suppress the protonated species. This is easier to achieve, but fragmentation of these adducts yields less sequence information than protonation. [Pg.359]


The interpretation of the mass spectra of oligosaccharide derivatives follows the general principles that have been elaborated for simple cyclic and acyclic carbohydrates (66MI1 74MI1). [Pg.345]

I he formation of J i ion (shown in 3) is of particular significance in the mass spectra of oligosaccharide-alditol derivatives, and requires the pre.s-... [Pg.101]

B. Kilster, T. J. P. Naven, and D. J. Harvey, Effect of the reducing-terminal substituents on the high energy collision-induced dissociation matrix-assisted laser desorption/ionization mass spectra of oligosaccharides. Rapid Commun. Mass Spectrom. 10, 1645-1651 (1996). [Pg.420]

Jacobs, A. Dahlman, O. Enhancement of the quality of MALDI mass spectra of highly acidic oligosaccharides by using a Nafion-coated probe. Anal. Chem. 2001, 73,405 110. [Pg.296]

The most easily recognizable fragment ions in the mass spectra of permethylated oligosaccharide alditols are those from nonreducing units, i.e., fragment ions at m/z 219 for permethylated hexose, m/z 189 for permethylated deoxyhexose, m/z 175 for permethylated pentose, m/z 233 for permethylated... [Pg.347]

The mass spectra of n-fructose-containing oligosaccharides as their permethyl derivatives follow, in most respects, the fragmentation patterns of the corresponding trimethylsilyl derivatives (see Section VI,3 p. 91). Permethylated aldobiouronic acids follow fragmentation routes similar to those of permethylated, neutral disaceharides. Thus, the A-series of fragments identifies a glycosyluronic residue (42) (see Scheme 39). [Pg.85]

Mass spectra of higher oligosaccharides containing hexuloses have been recorded. It was found that the presence or absence of a hexulose residue, and its location if present, could be established. [Pg.96]

Much of our knowledge on the fragmentation patterns of carbohydrate derivatives arises from studies on methylated monosaccharides, but in structural investigations, such compounds are seldom subjected to mass spectrometry. On the other hand, the molecular weight of a permethylated oligosaccharide is significantly less than that of the per(trimethylsilyl) derivative. For this reason, the mass spectra of disaccharides as -their permethylated alditols have been determined by Chizhov and coworkers, Karkkainen, and Krone and Beckey. Trisaccharides have also been studied by Karkkainen, either as permethylated glycosides or as alditols. ... [Pg.42]

The use of mass spectrometry in the structural analysis of carbohydrates, first reported in 1958 (114), was developed in detail by Kochetkov and Chizhov (115). They showed that, under electron impact, the acetylated and methyl ether derivatives of monosaccharides provided a wealth of structural information through analysis of typical fragmentation pathways of the initial molecular ion. This has proved of enormous utility in the structural elucidation of polysaccharides and complex oligosaccharides sequential permethylation, hydrolysis, reduction to the alditol, and acetylation, affords mixtures of peracetylated, partially methylated alditol acetates that can be separated and analyzed by use of a gas chromatograph coupled directly to a mass spectrometer (25). The mass spectra of stereoisomers are normally identical, while the gas chromatographic retention times readily permit differentiation of stereoisomers. [Pg.17]

Figure 7. Positive- (upper) and negative- (lower) ion MALDI mass spectra of the oligosaccharides obtained from birch wood xylan by mild acid hydrolysis. In positive ion mode, both neutral and acidic oligosaccharides are detected, whereas acidic oligosaccharides only are detected by negative-ion MALDI-MS. Reproduced from Reference 6. Copyright 2001 American Chemical Society. Figure 7. Positive- (upper) and negative- (lower) ion MALDI mass spectra of the oligosaccharides obtained from birch wood xylan by mild acid hydrolysis. In positive ion mode, both neutral and acidic oligosaccharides are detected, whereas acidic oligosaccharides only are detected by negative-ion MALDI-MS. Reproduced from Reference 6. Copyright 2001 American Chemical Society.
Compounds of D-glucose.—Proceedings of the Fourth International Symposium on Cyclodextrins have appeared. FAB and tandem mass spectra of 30 modified cyclodextrins have been reported, and it has been established that, in comparison with the internal bonds of linear oligosaccharides, the glycosidic bonds of a-, /3- and y-cyclodextrins are 1.5 fold more stable, approximately as stable, and 1.5 fold less stable, respectively, to acid-catalysed hydrolysis. ... [Pg.67]

IRLD) in which the primary mechanism is alkali ion attachment has been particularly useful for the analysis of neutral polymers. Figures 6.13 and 6.14 show the IRLD mass spectra of an oligosaccharide and an oligomeric mixture of polypropylene glycol, respectively. In the former, delayed extraction of the ions produces the opportunity for considerable in-source fragmentation that can be used for structural analysis. [Pg.127]

Coates, M.L. Wilkins, C.L. Laser Desorption Fourier Transform Mass Spectra of Malto-Oligosaccharides. Biomed. Mass Spectrom. 1985,12, 424-428. [Pg.549]

Coates, M. Wilkins, C. Laser desorption fourier transform mass spectra of malto-oligosaccharides. Biomed. Mass. Spectrom. 1985, 12, 424-428. [Pg.239]


See other pages where Mass spectra of oligosaccharides is mentioned: [Pg.254]    [Pg.93]    [Pg.358]    [Pg.357]    [Pg.42]    [Pg.538]    [Pg.254]    [Pg.93]    [Pg.358]    [Pg.357]    [Pg.42]    [Pg.538]    [Pg.125]    [Pg.262]    [Pg.121]    [Pg.148]    [Pg.228]    [Pg.352]    [Pg.353]    [Pg.358]    [Pg.2226]    [Pg.1004]    [Pg.256]    [Pg.308]    [Pg.263]    [Pg.331]    [Pg.333]    [Pg.214]    [Pg.187]    [Pg.398]    [Pg.162]    [Pg.229]    [Pg.241]    [Pg.235]   
See also in sourсe #XX -- [ Pg.93 ]




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