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A kind of assay method of degree of substitution of hydroxypropyl chitosan

A technology for hydroxypropyl chitosan and chitosan, which is applied in measuring devices, instruments, scientific instruments, etc., can solve the problems of difficulty, determination of the degree of substitution of hydroxypropyl chitosan, and unknown problems.

Active Publication Date: 2021-07-09
QINGDAO UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

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

Method used

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  • A kind of assay method of degree of substitution of hydroxypropyl chitosan
  • A kind of assay method of degree of substitution of hydroxypropyl chitosan
  • A kind of assay method of degree of substitution of hydroxypropyl chitosan

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Experimental program
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Embodiment 1

[0038] Reagents: KBr is optically pure, and acetanilide is a standard substance, both from Sinopharm Reagent Co., Ltd. Chitosan, derived from Laixi Haili Bioengineering Co., Ltd.; hydroxypropyl chitosan, using Chitosan No. 0 as raw material, reacts differently with propylene oxide at 45-60°C under alkaline conditions Time, hydroxypropyl chitosan No. 1-6 with different degrees of substitution purified by dealkalization method.

[0039] Instrument: the present invention is applicable to various Fourier transform infrared spectrometers, and instrument used in the present invention is the Fourier transform infrared spectrometer TENSOR 27 of German Bruker (Bruker) company; The degree of deacetylation and the degree of substitution of hydroxypropyl chitosan were completed in the testing center (national open laboratory) of the Institute of Bioenergy of the Chinese Academy of Sciences certified by the National Metrology Bureau. The instrument used was the Vario ELcube elemental analy...

Embodiment 2

[0055] The hydroxypropyl chitosan samples A, B, C, D, E, and F to be tested were all purified by hydroxypropylation and dealkalization. The degrees of deacetylation of the raw material chitosan are 92.2%, 93.8%, 94.4%, 95.1%, 96.3%, 97.6%, respectively. Compared with the raw chitosan (95.1%) of the hydroxypropyl chitosan sample used to establish the linear regression equation, the deacetylation degree differs by up to 3.05%. The hydroxypropyl chitosan to be tested dried according to the method (1) is passed through the Fourier transform infrared spectrometer according to the step (2a) and background detection and background processing are performed, so as to obtain an infrared absorption spectrum. According to the method of step ⑵b, in the OPUS software, select the R baseline integration method to use the whole waveform 3020-2380cm -1 The trough connection line is the baseline BL1, and the measured methyl characteristic peak is 2971-2962cm -1 The absorbance value A1 of the p...

Embodiment 3

[0060] The dealkalization purification method of hydroxypropyl chitosan

[0061] After the raw material chitosan undergoes hydroxypropylation reaction with propylene oxide under alkaline conditions, it needs to be purified by dealkalization. The de-alkalization purification method of the sample includes the de-alkalization method of alcohol washing, ketone precipitation, dialysis and partial neutralization ultrafiltration de-alkalization method.

[0062] In the alcohol washing ketone precipitation dialysis dealkalization method, firstly, the product mixture is suction-filtered to remove the solvent and residual alkali. Add water to dissolve the crude product after suction filtration, filter, add ethanol to the filtrate to make it contain 75% ethanol, add acetone while stirring to precipitate the swollen chitosan, filter, and add the precipitate to 75% ethanol , and so on, until the ethanol aqueous solution of hydroxypropyl chitosan is neutral, then precipitate it with acetone...

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Abstract

The invention discloses a method for measuring the degree of substitution of hydroxypropyl chitosan, which comprises: (1) drying a sample of hydroxypropyl chitosan. (2) Establish a detection model: a. Use an infrared absorption spectrometer to obtain the infrared absorption spectrum of the above sample; b. Measure the methyl characteristic peak 2971-2962cm ‑1 3020‑2380cm across the entire waveform ‑1 The absorbance value of the peak height measured on the baseline formed by the trough connection line is A1 and the characteristic peak of the amino group at the C2 position is 1602‑1590cm ‑1 The ratio X of the absorbance value A2 of the peak height measured on the baseline constituted by the peak-valley line; c. measure the degree of substitution Y of the hydroxypropyl chitosan sample with standard methods; d. establish linearity with Y to X Model Y=kX+b, so as to obtain the specific values ​​of k and b in the model. (3) Substituting the ratio X obtained from the infrared absorption spectrum of the sample to be tested into the above linear regression model, the degree of substitution Y can be obtained by calculation. The method is simple, quick, accurate, and does not require precise weighing and dissolution of samples.

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, moisture retention, film-forming, foaming, free radical scavenging, antibacterial, and adsorption (Cheng Z, et al.Effects of hydroxypropylde...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N21/3563
Inventor 张永勤张坤张捷张丹丹
Owner QINGDAO UNIV OF SCI & TECH