FT-NIR Review of Application Limits and Application to Chitosan Characterization

Abstract

This thesis reviews recent applications of NIR spectroscopy, specifically focusing on O-H, N-H and C-H bonds found most commonly in water, alcoholic beverages, proteins and sugars, and identifies practical errors associated with this measurement method. In addition, the degree of deacetylation (DD) of chitosan was experimentally characterized by NIR in comparison to other analytical methods. Chitosan is a natural derivative of chitin that is mostly found in crustaceans. It possesses unique biological properties, which rely upon the DD: the ratio of free amino groups to acetyl groups within the chitosan molecule. The DD is an important characteristic due to its direct influence on functionality of chitosan. This work explores the direct measurement of DD for chitosan powders using FT-NIR spectroscopy, providing a fast analysis method, which does not require significant sample preparation. The developed method was capable of determining DD to within +-0.4% for samples between 80 and 100% DD.