A novel titration method based on fiber-optic refractive index sensing for the determination of deacetylation degree of chitosans

Abstract

We describe a novel method for determining the degree of deacetylation (DD) of chitosans from fiber-optic measurements of refractive index. Theory analyses and the experimental setup of the method are introduced and discussed. The analytical performance of the method is described for the determination of alkaline titration end-points. Experimental results reveal that the equivalence point can be directly identified from the titration curve. The proposed method is simple, low-cost, accurate, reliable, and easy to operate for industrial application. The DD values of four chitosan samples obtained with this new method show good agreement with those yielded from 1 H NMR. Such a mechanism of refractive-index monitor should open up a new application in the field of chitosanolytic enzymes, such as chitosanase, pectinase that are important in bioprocesses.

Innovative method to avoid the reduction of silver ions to silver nanoparticles $\left( {\rm A}{{{\rm g}}^{+}}\to {\rm Ag}{}^\circ \right)$ in silver ion conducting based polymer electrolytes

“…In addition, chitosan (CS) is a cationic polysaccharide, which contains β-1-4-linked 2-amino-2 deoxy-D-glucopyranose repeat units and is readily obtained by alkaline N-acetylation of chitin [6]. CS has great potential as a biomaterial because of its good biocompatibility [7], biodegradability, low toxicity, low cost [8], medical and pharmaceutical applications [9], antimicrobial activity [10], hydrophilicity (which is of benefit to fuel cell operation), and chemical and thermal stability at higher temperatures [11]. Thus, CS has become of great interest not only as an under-utilized resource but also as a new functional biomaterial of high potential in various fields [12].…”

Role of Hard-Acid/Hard-Base Interaction on Structural and Dielectric Behavior of Solid Polymer Electrolytes Based on Chitosan-XCF3SO3(X = Li+, Na+, Ag+)

“…Chitosan is a biocompatible and biosorbable biopolymer which is currently receiving a great deal of interest for medical and pharmaceutical applications due to its interesting intrinsic properties [8] and it is a polycationic polymer due to the existence of one amino group and two hydroxyl groups in their repeating units [9]. It is well known that chitosan is an outstanding sorbent of extremely high affinity for transition metal ions due to the abundance of polar groups (NH 2 and OH) in chitosan chains which served as conjunction sites [10].…”