A method for measuring n-degree of substitution, total degree of substitution and degree of acetylation of hydroxypropyl chitosan

Abstract

The invention discloses a method for measuring N-substitution degree, total substitution degree and acetylation degree of hydroxypropyl chitosan, specifically comprising the following steps: sample preparation: a. drying hydroxypropyl chitosan sample; b. drying Add a deuterated reagent to a good hydroxypropyl chitosan sample until it is completely dissolved; sample testing: obtain the nuclear magnetic resonance spectrum of hydroxypropyl chitosan by a nuclear magnetic resonance instrument; data processing: obtain the nuclear magnetic resonance spectrum from In the process, the spectral assignment is first carried out, and then the area integration and calculation of each proton peak are carried out; the calculation formulas of N-substitution degree, total substitution degree and acetylation degree of hydroxypropyl chitosan are obtained. This application can detect two independent H 9‑N proton peak and H 9‑O Proton peak, through H 9‑N The proton peak can detect the ratio of the hydroxypropylated sugar unit of the amino group in the hydroxypropyl chitosan molecule. Compared with the method for measuring the degree of substitution in the prior art, the present invention has more clear and detailed attribution, more accurate measurement, multi-indicator efficiency, simplicity and speed.

Description

technical field [0001] The invention belongs to the field of research and application of hydroxypropyl chitosan, and relates to a method for measuring the degree of substitution of hydroxypropyl chitosan, in particular to a method for measuring the N-degree of substitution of hydroxypropyl chitosan by proton nuclear magnetic resonance , total substitution degree and acetylation degree method. Background technique [0002] Chitosan has good biocompatibility, biodegradability, stability, and safety, but its water solubility is poor, and it can only be dissolved in acidic media, and chitosan is hydroxypropylated to form a hydroxypropyl shell Glycans (HPCTS) can improve their solubility, thereby greatly broadening their application fields and development process. Studies have shown that hydroxypropyl chitosan has solubility, hygroscopicity, moisturizing properties, film-forming properties, foaming properties, free radical scavenging properties, antibacterial properties, and ads...

AI Technical Summary

Problems solved by technology

The difference from ordinary small molecules is that there are a variety of intramolecular and intermolecular interactions in the structure of hydroxypropyl chitosan. Therefore, it is easy to quantitatively calculate the number of protons in the corresponding environment by using the integration of proton peaks at different chemical shifts. Introduce errors; on the other hand, because the test conditions are not optimized enough, the characteristic peaks overlap and cannot be measured as a single peak, resulting in the H in the denominator 2-8 Integral measurements are small, thereby significantly increasing the degree of substitution measurement, and more importantly, the presence of N-substitution cannot be detected

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