Determination of the Degree of Deacetylation in Chitosan and its Salts by Proton Nuclear Magnetic Resonance Spectroscopy

Chemical reactions on the structure of polymers، especially natural polymers result in production of new properties. One of these cases is chitin deacetylation reaction for production of chitosan. Property and application of chitosan with extensive uses in food، cosmetic، healing and drug industries depend on the degree and percent of acetyl groups or in other words the degree deacetylation (DDA). Proton nuclear magnetic resonance spectroscopy (1HNMR) is the simplest، most accurate and fastest method for quantitative determination of the degree of deacetylation in chitosan and its salts. In this method، the degree of deacetylation، ranging from 50 to 100%، with acceptable accuracy and repeatability is determined by a small amount of material without undergoing degradation and simple calculation. In addition، if the molecular weight of polymer is low، this test method can determine the number average degree of polymerization (DPn) in chitosan and chitosan salts for use in biomedical and pharmaceutical applications.