Spectroscopic approaches for structural analysis of extracted chitosan generated from chitin deacetylated for escalated periods

A conventional chemical method was applied for the extraction of chitosan (CH) from shrimp shell wastes (SSWs) in three stages: (1) Demineralization: SSWs were treated with HCl to remove minerals. (2) Deproteinization: NaOH was used to eliminate proteins from the demineralization shells. 3: Deacetylation: The chitin (CT) obtained from stage 2 was converted to chitosan in alkaline medium using NaOH. This study aims to demonstrate the impact of varying deacetylation times on chitosan surface morphology, elemental composition, thermal resistance, structural configuration, and deacetylation degree (DD). Variable techniques including UV-visible spectroscopy, Fourier Transformed Infra-Red (FTIR-ATR), Thermogravimetry (TG/DTG), Scanning Electron Microscopy (SEM), and Energy-dispersive X-ray spectroscopy (EDX) analyses were employed to analyze how increased deacetylation periods affect the characterization of the products. The FTIR spectra showed a notable similarity between all extracted chitosan processed with increasing deacetylation time and the commercial one. Moreover, the results revealed that all the extracted chitosan samples acquired DD values, based on FTIR-ATR analysis, are comparable to that of commercial ones i.e. 79.54%, 78.23%, 74.81%, and 76.56% for deacetylated times of 22 h, 30 h, 36 h, and 40 h, respectively are comparable to that of the commercial chitosan (76.1%). Furthermore, the EDX analysis confirms that the extracted chitosan is non-toxic product, making it suitable for various applications, including biological and medical uses.