Hydrolysis of Chitosan Using Ultraviolet Irradiation and Hydrogen Peroxide

In this study, molecular weight of chitosan was reduced by using ultraviolet (UV)-irradiation (wavelength=254 nm) and hydrogen peroxide (H2O2), simultaneously. The efficiency of the depolymerization was demonstrated by determination of viscosity-average molecular weight. Moreover, the structure of the depolymerized chitosan was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Nuclear magnetic resonance (1H NMR) and UV–visible (UV-Vis) spectroscopy. The FTIR and 1H NMR studies demonstrated the breakage of 1,4-β-D-glucoside bonds of chitosan. XRD quantitative analysis also showed that crystalline structure of the chitosan changed during depolymerization. The results showed that combined UV-irradiation/H2O2 method was significantly efficient for preparing low molecular weight chitosan and could be applied in scale-up production of the depolymerized chitosan