Characterization of chitosan extract from Etok shell (Corbicula fluminea)

Chitosan is a linear polysaccharide derived from chitin by the deacetylation process, with a wide range of potential commercial and medicinal applications. In this study, chitosan was extracted from etok shell (Corbicula Fluminea) through the chemical extraction process. Deproteination, demineralization, depigmentation and deacetylation were involved in the extraction process and the purity of chitosan produced from was determined through its degree of deacetylation. Characterization of chitosan has been done using elemental analysis (CHNS) to determined the carbon, hydrogen, sulfur and oxygen and other analysis using Fourier Transform Infrared (FTIR), Differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA), X-ray diffraction (XRD) and solubility test. The degree of deacetylation obtained from elemental analysis was found to be very low with 15.92%. While preliminary results of FTIR revealed that different functional groups of C-O, NH2 and amide group were observed in the chitosan extracted from etok shells. DSC showed endothermic peak (692°C to 726°C) and exothermic peak (718°C to 759°C). The TGA reveals the onset of the first phase was observed at approximately 83.75 °C with weight loss 6.86%, while the second phase commences around 571.25 °C with weight loss of 40.36%. The characteristics XRD showed very weak peaks in the spectra at 10.67° and 20.52° which suggest a low crystallinity and an amorphous nature of the product. Solubility tests indicate that chitosan is 99% soluble in acetic acid and 5.55% insoluble in distilled water.