Method for determining substitution degree of hydroxypropyl chitosan

Abstract

The invention discloses a method for determining the substitution degree of hydroxypropyl chitosan. The method comprises the steps that 1, a hydroxypropyl chitosan sample is dried; 2, a detection model is established, and the establishment process comprises the steps that a, an infrared absorption spectrum of the sample is obtained through an infrared absorption spectrometer; b, the specific value X of an absorbance value A1 of the area of a methyl characteristic peak ranging from 1460 cm<-1> to 1456 cm<-1> to an absorbance value A2 of the peak height of a characteristic peak, ranging from 1602 cm<-1> to 1596 cm<-1>, of amino on the C2 position is determined; c, the substitution degree Y of the hydroxypropyl chitosan sample is determined through a standard method; d, a good linear regression model Y=kX + b is established by using Y on X, and therefore specific values of k and b in the model are obtained; 3, the specific value X, obtained through the infrared absorption spectrum, of the sample to be determined is substituted into the linear regression model, and then the substitution degree Y can be obtained through calculation. The method is simple, convenient, rapid and accurate, and precise weighing and sample dissolution are not needed.

Description

technical field [0001] The invention belongs to the field of research and application of detection methods for the degree of substitution of hydroxypropyl chitosan, and relates to a method for determining the degree of substitution of hydroxypropyl chitosan, in particular to an infrared absorption spectrometry method for determining the degree of substitution of hydroxypropyl chitosan. 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 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, antibacterial properties, and adsorption pro...

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Problems solved by technology

[0007] However, the research on hydroxypropyl chitosan has been started since the 1980s at home and abroad. Researchers generally use its infrared absorption spectrum as one of the methods for structural characterization, but so far, no use of this method has been used to determine hydroxypropyl chitosan. Related reports on degree of substitution of chitosan

The reason is that, on the one hand, the extremely small amount of impurities in the hydroxypropyl chitosan sample can make its infrared spectrum "clearly discern the details" and appear, and directly affect the peak shape and peak position changes of the characteristic peaks (Zhang Yongqin, Zhang Kun. The effect of separation and purification methods on the determination of the structure and degree of substitution of hydroxypropyl chitosan. Journal of Qingdao University of Science and Technology, 2015, 36(3):251-254); on the other hand, hydroxypropylation itself will also make it The characteristic peaks overlap, deform, migrate, etc., and it is difficult to find a constant characteristic peak of a certain structure as a reference peak for the calculation of the degree of substitution

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