Determination of degree of deacetylation of chitosan by1H NMR spectroscopy

✍ Scribed by Asako Hirai; Hisashi Odani; Akio Nakajima

• Publisher: Springer
• Year: 1991
• Tongue: English
• Weight: 310 KB
• Volume: 26
• Category: Article
• ISSN: 0170-0839
• DOI: 10.1007/bf00299352

✦ Synopsis

This paper describes a novel method to determine the degree of deacetylation of chitosan by IH NMR spectroscopy. Measurements were carried out at 70~ by using 2 wt% CD3COOD/D20 and 2 wt% DCI/D20 as solvents for chitosan.

In the case of DCI/D20 system, effect on hydrolysis of chitosan should be taken into consideration, and the pulse repetition delay required for 45 ~ pulse is 40s. Whereas, in regard to CD3COOD/D20 system, 6s pulse repetition delay is enough for 45 ~ pulse, and moreover, high magnetic field NMR apparatus is necessary, because signal of CD2H residue in CD3COOD overlaps with that of CH 3 residue in N-acetyl residue and determination of the difference of two spectra is required. The proposed method is more effective, precise and simple, comparing with the conventional colloid titration and elemental analysis methods. Assignments of IH and 13C NMR spectra of chitosan are also reported.