The O-carboxymethylchitosan (O-CMQ) was derivatized from the chitosan copolymer by the direct alkylation method. This method involved the reaction of the chitosan with monochloroacetic acid after alkalinization. The derivatized product showed solubilityin a pH range of 1-13 and low solubility at pH = 5. The degree of substitution (GS) was 0,92, determined by conductometric titration. The results of Fourier Transform Infrared Spectroscopy (FT-IR) allowed us to identify a strong intensity absorption band at 1585cm-1, corresponding to the stretching of C = O, which indicates the presence of a carboxylic anion (-COO- ) that is characteristic of O-carboxymethylchitosan (O-CMQ). Using the Nuclear Magnetic Resonance spectroscopy of proton and carbon-13 (1 H NMR, 13C NMR) showed that the substitution was carried out on carbon 3 and 6 of chitosan. The derivatized O-CMQ at concentration of 50mg / ...