Solid State NMR for Determination of Degree of Acetylation of Chitin and Chitosan

The degree of acetylation (DA) of various samples has been evaluated by 1H liquid-state NMR and 13C and 15N CP−MAS solid-state NMR over the whole range of DA. A good agreement has been found for all the experiments. The 13C and 15N CP−MAS experiments have permitted the evaluation of the chitin DA and content in the structural polysaccharides in a fungus named Aspergillus niger. The fungus structural carbohydrates mainly consist in pure chitin associated with glucans. Comparison of the 13C CP−MAS spectra with standard (1→3)-β-d-glucans strongly suggests that chitin and glucans are linked via covalent bonds.