Application of Infrared Spectroscopy to Carbohydrates

These questions have stimulated a great deal of interest in the infrared 

Weigl studied the exchange reaction between ascorbic acid and heavy water. An examination of the 0—H and C—H stretching frequency region of the normal and the deuterated compound led him to the conclusion that ascorbic acid contains labile hydrogen atoms attached to both carbon and oxygen. 

Stacey has written an excellent review on the subject of mucopolysaccharides, which he classified on the basis of their containing both hexosamine and hexuronic acid residues, one or the other of these sugar derivatives, or neither. Hyaluronic acid, chondroitinsulfuric acid. Type I pneumococcal polysaccharides, and heparin are members of the first class. Types II, III, and VIII pneumococcal polysaccharides are examples containing hexuronic acid but no hexosamine. Chi tin and Types IV and XIV pneiuno-coccal polysaccharides contain hexosamine but no hexuronic acid and bacterial dextrans, mold polysaccharides, and levans contain neither hexosamine nor hexuronic acid. 

Fletcher and Diehl, in studying the preparation of melibiose from raffinose by the fermentative hydrolysis of the trisaccharide, noticed a new form of the disaccharide. By observing the mutarotation of the new form, and by comparing the infrared spectra with that of an authentic 

A trisaccharide produced from sucrose by Aspergillus niger (152) was investigated by Barker, Bourne and Carrington. During the course of this study they compared the infrared spectra of their trisaccharide and of a known trisaccharide produced from sucrose by Takadiastase (a commercial, mold-enzyme preparation). The spectra were identical, and later methylation and hydrolysis studies confirmed the fact that the two trisaccharides were the same. 

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