Determining the Deacetylation Degree of Chitosan: Opportunities To Learn Instrumental Techniques

To enhance critical thinking and problem-solving skills, a project-based learning (PBL) approach for Instrumental Techniques courses in undergraduate physical chemistry was specifically developed for a pharmacy bachelor degree program. The starting point of this PBL was an open-ended question that is close to the student scientist's interest and related to this lab: How can we determine the deacetylation degree of chitosan? Chitosan is a polysaccharide used in a broad range of pharmacy applications because of its unique properties. Many of these properties derive from the presence of primary amino groups (-NH2) in its structure. These -NH2 groups are usually formed by the deacetylation of chitin. For this reason, a proper quantification of the deacetylation degree (DD) of chitosan is important to know whether it can be used in a particular application. This driving question requires an experimental procedure that can be carried out by a wide range of instrumental techniques. In this project, techniques such as conductometry, potentiometry, and H-1 NMR were addressed to present an easily reproducible experience for first-year undergraduate students. Students evaluated the applicability of the available instrumental techniques, designed their own laboratory procedures, obtained experimental results, and analyzed data in a challenging experience in which high order thinking and knowledge transfer skills were endorsed. The project described here promotes students' knowledge of instrumental techniques, and offers them an appropriate scenario to develop transferable skills, such as team-working, problem-solving, and written communication, among others.