Oligosaccharides acetylated, mass spectrometry

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. 

Shen X, Perreault H (1999) Electrospray Ionization Mass Spectrometry of 1-Phenyl-3-methyl-5-pyrazolone Derivatives of Neutral and N-Acetylated Oligosaccharides. J Mass Spectrom 34 502... 

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. 

Dell A. Preparation and desorption mass spectrometry of permethyl and per-acetyl derivatives of oligosaccharides. Methods Enzymol 1990 193 647-660. 

Yamagah, T Suzuki, H. Tachibana, K. Semiquantitative analysis of isomeric oligosaccharides by negative-ion mode UV-MALDl TOF postsource decay mass spectrometry and their fragmentation mechanism study at Af-acetyl hexosamine moiety. 

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