I don't understand why my Chitosan sample (Sigma Aldrich Medium Molecular weight) is not soluble in HCl 2M solution (pH 1) but soluble in 2% Acetic acid solution (pH 4). For a hydrolisis protocol i need a HCl 2M Chitosan 1% Solution.
Thank you for your responses.
Dear Luciano Dibona, many factors are involved in chitosan solubility: MW, degree of substitution, pH, concentration, ...... Please check the following link and attached files. My Regards
https://www.researchgate.net/post/Solubility-of-Chitosan
Dear Luciano Dibona,
I have attached an article that can help you find an appropriate solution to your problem. In this article, you can find information about different types of acids for chitosan dissolving, required heating treatment, etc.
Best regards.
Hi;
The solubility of chitosan depends on the DD of this polymer. The more it is deacetylated, the more free amine groups there are, the more soluble chitosan is. The concentration ratio between chitosan and acid is of great importance. There are several critical factors affecting chitosan solubility including temperature and time of deacetylation, alkali concentration, and prior treatments applied to chitin isolation, ratio of chitin to alkali solution, and particle size.
Chitosan is readily soluble in dilute acidic solutions at pH less than 6.0. Organic acids such as acetic, formic and lactic acids are used to dissolve chitosan. The most commonly used is a 1% acetic acid solution at a pH of about 4.0 as a reference. The solubility of chitosan in inorganic acids is quite limited. Concentrated acetic acid solutions at high temperatures can cause depolymerization of chitosan. Above pH 7.0, the solubility of chitosan is poor. At high pH, precipitation or gelation tends to occur and the chitosan solution forms a poly-ion complex with an anionic hydrocolloid, resulting in the formation of a gel. Please check the following document.
With my best regards
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