Polysaccharides by hydrolysis

In most cases, uronic acids are liberated from acidic polysaccharides by hydrolysis leading to irreproducible concomitant formation of lactones. Several methods to circumvent this problem have been published describing conversion of the uronic acid into methyl esters followed by reduction with borohydride or borodeuteride reagents and subsequent hydrolysis and GC-MS detection [129]. Other techniques are based on the liberation and quantification of carbon dioxide. Direct determination of uronic acid residues in hydrolyzates has frequently been performed according to colorimetric assays, which are rather insensitive and have thus mostly been replaced by high-performance anion exchange chromatography (HP-AEC) methods [130-132]. 

The cleavage of polysaccharides by hydrolysis with acid, by oxidation with periodate or chromium trioxide, by base-catalysed jS-elimination, by deamination, and by Weermann and Lossen rearrangements has been ably reviewed. A new approach to selective cleavage of the glycosidic bond to the reducing-end residue of oligosaccharides has involved base-catalysed j8-elimination on a model 5-deoxy-5-nitromaltitol derivative. ... 

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