An infrared study of various nitrated polysaccharides and their structural characterisation

Infrared absorption spectra for a number of polysaccharides and their nitrated derivatives have been obtained. The frequency range 730–960 cm^?1 is useful for identification of the polysaccharides, and the region 900–1350 cm^?1 is more suitable for distinguishing the nitrated materials. The strong intensity of the nitrate bands limits the interpretation of spectra below 960 cm^?1, but above this frequency the absorption bands of nitrated polysaccharides are generally sharper and more clearly defined than the corresponding bands of the parent polysaccharides. Data on the COC bridge, CC ring, CO, and COH frequencies and on the CH deformation and stretching frequencies have been obtained. The use of i.r. spectroscopy for the quantitative determination of nitrate groups in nitrated polysaccharides is discussed.