Determining the degree of acetylation of chitin/chitosan using a SSNMR 13C method on the basis of cross polarization reciprocity relation

Abstract

The degree of acetylation (DA) is an essential parameter for chitin and its derivatives, which determines the chemical and physical properties of the polymers. As a consequene, fast and accurate technique to determine DA is widely required when developing the relating materials. Herein, an improved quantitative SSNMR method of rQCPZRC, based on the cross polarization reciprocity relation, was discussed and employed for DA testing. Three chitin/chitosan samples were chosen to evaluate the performance of rQCPZRC. In comparison with quantitative DP and optimized contact time CP methods, rQCPZRC is revealed as an accurate and reliable DA testing method with relative percentage errors of less than 5%. Moreover, the experimental time of rQCPZRC for each sample is 5.5 h, notably shorter than DP of 36–85 h. Thus, our work suggests rQCPZRC as a tool for DA testing, which is capable to accomplish with high accuracy and efficiency.