An optimised method to determine the degree of acetylation of chitin and chitosan by FTIR spectroscopy

Linking up the user-friendly and low-priced FTIR with the more sophisticated and high-priced 13C CP/MAS NMR spectroscopies, an improved method to determine the degree of acetylation (DA) of chitins and chitosans was outlined. The method was established for the most complex polymorphic form (α-chitin) and for the most problematic range of DA values (most acetylated samples) and can easily be extended to the other polymorphic forms (β- and γ-chitins) and to other ranges of DA values.