Suitability for Determination of Deacetylation Degree of Chitosan

To choose a simple and accurate method for the determination of deacetylation degree of chitosan,the study evaluated six current methods from different aspects including the measurement accuracy,precision and versatility. The results showed that the modified acid-base titration was simple,and the accuracy was 97.01%,and the RSD of precision was 0.33%. Linear potentiometric titration needed less sample point,so it was more convenient and time-saving compared with double-dip titration. UV Spectroscopy and infrared spectroscopy required special equipment. Colloidal titration was sensitive to the change of color,but titration speed was limited and the precision was low. The versatility of modified acid-base titration,linear potentiometric titration and UV spectroscopy showed that they had good universality. UV Spectroscopy was adapted to determination of degree of deacetylation of chitosan with low molecular weight(≤ 100000). Linear potentiometric titration was adapted to chitosan with high viscosity(≥ 400 mPa·s). The degree of deacetylation of other kinds of chitosan could be determined by the improved acid-base titration method,which was simple and accurate.