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Method for determining substitution degree of hydroxypropyl chitosan

A technology of hydroxypropyl chitosan and determination method, which is applied in the direction of color/spectral characteristic measurement, etc., can solve the problems of unfavorable experimental results, high accuracy and large-scale application, and decrease of absorbance value, so as to optimize reaction time and optimize Effect of reaction temperature and accuracy improvement

Active Publication Date: 2015-06-10
QINGDAO UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In the specific experiment, it was found that the reproducibility and stability of the results obtained by carrying out the experiment according to the above operating parameters were poor
First of all, the boiling water bath environment at 100°C is not conducive to manual operation, and the reaction product at this temperature is extremely sensitive to changes in the reaction time, and a slight extension or shortening of the reaction time will affect the amount of the reaction product (see the appendix Figure 1-3 ), which has very high requirements for the operator to control the reaction time in the experiment, which is extremely unfavorable for obtaining accurate and reliable experimental results, resulting in poor reproducibility; in addition, at the detection wavelength of 590nm, the absorbance value of the chromogenic product is extremely unstable, As the detection time prolongs, the absorbance value shows a clear downward trend (see attached Figure 4-6 ), even if the time interval between two detections is 20 minutes, the absorbance value will change significantly, which is also not conducive to obtaining accurate and reliable experimental results, and it is not conducive to industrial mass determination
[0005] To sum up, the existing absorptiometry has big problems in accuracy and large-scale application, which is not conducive to the promotion and use of the method.

Method used

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  • Method for determining substitution degree of hydroxypropyl chitosan
  • Method for determining substitution degree of hydroxypropyl chitosan
  • Method for determining substitution degree of hydroxypropyl chitosan

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] Accurately weigh 30.0 mg of hydroxypropyl chitosan (5% acetylation degree) that has been dried and dehydrated, and use a volumetric flask to prepare 50.0 mL of HCl solution with a concentration of 0.600 mg / L as a solvent. mL of hydroxypropyl chitosan solution was reacted according to the above-mentioned specific embodiment and the absorbance value of the product was measured at 550nm.

[0051] The formula for calculating the degree of substitution of hydroxypropyl chitosan is as follows:

[0052]

[0053] in:

[0054] 1.c 丙二醇 :

[0055] ABS 羟丙基壳聚糖 =0.527, where ABS is the absorbance value

[0056] Substituting this value into the propylene glycol standard curve identical to the HCl solution of 0.007mol / L as the solvent and measuring wavelength of hydroxypropyl chitosan: y=0.3345x+0.0173, where y is the absorbance value, and x is Corresponding to the concentration of propylene glycol (c 丙二醇 ),have to:

[0057] c 丙二醇 =x=(0.527-0.0173) / 0.3345=1.52 μmol / mL

[00...

Embodiment 2

[0067] Accurately take by weighing 30.0 mg of a hydroxypropyl chitosan (acetylation degree of 5%) sample with a water content of 12.0%, and use a volumetric flask to prepare 50.0 mL of 0.600 mg / mL HCl as a solvent with a concentration of 0.600 mg / mL. Solution, react according to the above-mentioned specific embodiment and measure the absorbance value of the product.

[0068] The formula for calculating the degree of substitution of hydroxypropyl chitosan is as follows:

[0069]

[0070] in:

[0071] 1.c 丙二醇 :

[0072] ABS 羟丙基壳聚糖 =0.946, where ABS is the absorbance value

[0073] Substituting this value into the propylene glycol standard curve identical to the HCl solution of 0.007mol / L as the solvent and measuring wavelength of hydroxypropyl chitosan: y=0.3345x+0.0173, where y is the absorbance value, and x is Corresponding to the concentration of propylene glycol (c 丙二醇 ),have to:

[0074] c 丙二醇 =x=(0.946-0.0173) / 0.3345=2.78 μmol / mL

[0075] 2.V:

[0076] In this...

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Abstract

The invention discloses a method for determining the substitution degree of hydroxypropyl chitosan by use of an absorption photometry. The method is characterized by comprising the following steps: A. drawing a standard correspondence curve of the absorbance value of the oxidation product of propylene glycol and the concentration of propylene glycol by use of the absorption photometry; B. detecting the absorbance value of the oxidation product of to-be-detected hydroxypropyl chitosan after hydrolysis and oxidation, equivalent to the absorbance value of the propylene glycol, by use of the absorbance value; determining the content of the oxidation product equivalent to the propylene glycol, generated by hydrolysis of the to-be-detected hydroxypropyl chitosan according to the standard correspondence curve of the absorbance value of the oxidation product of the propylene glycol and the concentration of propylene glycol, and calculating the content of hydroxypropyl contained in the hydroxypropyl chitosan. According to the method, the key parameters such as reaction temperature, reaction time and detection wavelength can be selected, the determining stability is improved greatly, the stability of the absorbance value of the color substance is increased to 3h from 0.5h in the reported method, the method can realize mass determination conveniently and the accuracy of the experimental result is ensured.

Description

technical field [0001] The present invention relates to a method for measuring the degree of substitution of hydroxypropyl chitosan, in particular to a method for measuring the degree of substitution of hydroxypropyl chitosan by absorbance photometry, in particular to the reaction temperature, reaction time and detection wavelength in the determination process s Choice. Background technique [0002] Chitosan has good biocompatibility, biodegradability, stability, and safety, but its low water solubility greatly limits its application in the fields of biopharmaceuticals, wastewater treatment, functional membrane materials, and textiles. Hydroxypropylation can improve the water solubility of chitosan, thereby improving its application in various aspects. The degree of hydroxypropyl substitution (DS) is defined as the average number of hydroxypropyl groups attached to each molecule of glucosamine and N-acetylglucosamine. The degree of substitution determines the physical and ...

Claims

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Application Information

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IPC IPC(8): G01N21/31
Inventor 张永勤张坤刘福胜刘征东程袁芬吴国耀刘均洪戴圆圆边文涛
Owner QINGDAO UNIV OF SCI & TECH