CN-122016779-A - Method for detecting beta-cyclodextrin

Abstract

The invention belongs to the technical field of chemical detection, and provides a method for detecting beta-cyclodextrin, which comprises the steps of increasing the temperature of feed liquid containing beta-CD to 65 ℃ or more and less than 85 ℃, clathrating phenolphthalein under the condition of heat preservation, and then detecting the color development degree in an alkaline environment. The invention greatly widens the detection range, does not need complicated dilution, simplifies the operation, improves the efficiency, avoids errors introduced in the dilution process, and can be directly suitable for detecting common high-concentration samples in industrial production.

Inventors

• KONG YAZHOU
• WANG JINGHUA
• ZHANG XIAOYUAN
• LIU YANXIN
• LI YIZHEN
• LIU DAYONG
• MING XIA
• ZHANG YAN
• LIU FEI
• ZHANG DAIZHOU
• CHEN MIAN
• WANG JINGYI
• JIN ZHENHUA
• ZHANG JINHUA
• NIU LINLIN
• WEI QIAN

Assignees

• 曲阜市天利药用辅料有限公司
• 山东省药学科学院

Dates

Publication Date

20260512

Application Date

20260414

Claims (5)

1. 1. A method for detecting the content of beta-CD is characterized by comprising the steps of raising the temperature of a feed liquid containing beta-CD to 65 ℃ or higher and 85 ℃ or lower, clathrating phenolphthalein under the condition of heat preservation, and then detecting the color development degree in an alkaline environment.
2. 2. The method of claim 1, wherein the concentration of β -CD in the feed solution is no greater than 15 wt%.
3. 3. The method according to claim 1, wherein the degree of color development is determined using a color chart or an absorbance value.
4. 4. The method according to claim 1, comprising the steps of: Under the condition of heat preservation of 65-85 ℃, preparing beta-CD solution with the weight concentration of 0.128-0.136 g/g, preparing each concentration point of a standard curve with the maximum concentration of 20%, 40%, 60%, 80% and 100%, taking 4 parts of each concentration sample, respectively adding 3-4 parts of 0.01-0.014% (w/v) phenolphthalein solution, and then adding alkali to ensure that the pH value of the system is more than or equal to 8.2. And standing for 2-30 minutes after uniformly mixing, sampling to measure absorbance value, fitting a regression curve equation of the beta-CD mass and absorbance value, and calculating the mass of the beta-CD in the sample liquid to be measured.
5. 5. The method of claim 4, wherein the incubation conditions are 70-75 ℃.

Description

Method for detecting beta-cyclodextrin Technical Field The invention belongs to the technical field of chemical detection, and particularly relates to a method for detecting beta-cyclodextrin based on a spectrum analysis method. Background This background information is disclosed to enhance an understanding of the general background of the invention and is not necessarily to be considered an admission or any form of suggestion that this information constitutes prior art already known to a person of ordinary skill in the art. In the enzymatic conversion process based on beta-cyclodextrin (beta-CD), the feed solution prior to secondary crystallization is typically heated to near boiling to solubilize the beta-CD, followed by crystallization purification by cooling. In order to accurately control the crystallization process and evaluate the yield, the concentration of beta-CD in the feed liquid needs to be rapidly and accurately detected. However, since β -CD has very low solubility at normal temperature, rapid cooling after sampling at high temperature can lead to β -CD precipitation, forming an unstable suspension system, which makes quantitative sampling and analysis a significant challenge. Existing analytical methods for detecting beta-CD include spectrometry, chromatography, enzymatic methods, and the like. In the analysis method, compared with other methods with equipment, the spectrum analysis method has the advantages of low cost, simple operation, good method stability, good reproducibility and the like, and becomes a common method for detecting the beta-CD concentration. However, for complex suspensions of unknown β -CD concentration containing other substrates as described above, this technique has a significant limitation in that it is difficult to determine a low range of commonly used concentrations (e.g., 0.5-1 mg/mL). According to the prior art documents and published data, when the method is adopted for detection, the solubility of the beta-CD is about 1.8% (w/v or v/v) at normal temperature, and the characteristic severely limits the application of the method in direct detection of high-concentration beta-CD samples, so that complicated dilution steps are required to be carried out when the samples beyond the range are detected, the operation complexity is increased, and additional error risks are introduced. For example, in experiments using high performance liquid chromatography to measure the concentration of β -CD in the feed solution prior to secondary crystallization, the suspension may be oscillated, rapid sampling may be attempted intermittently during oscillation, and gradient dilution may be performed to obtain a homogeneous solution for sample injection. However, in practical application, the suspension is extremely easy to delaminate, sampling representativeness is affected even though the suspension stands for a short time, and when diluted samples are injected into HPLC, because the temperature of a sample chamber of an instrument is very lower than the room temperature, beta-CD is precipitated at a low temperature part before entering a temperature control chromatographic column (such as 40 ℃), a column head is blocked, the column pressure is increased and a system is alarmed, and the obtained concentration data cannot truly reflect the condition of original feed liquid. To alleviate the precipitation problem, the HPLC sample chamber temperature is determined in advance and diluted with a solvent not higher than this temperature. However, not only does this increase the complexity and time cost of sample pretreatment, but also the dilution factor is difficult to determine once due to the narrow linear detection range of HPLC, and often requires repeated attempts. More importantly, the concentration of the suspension system which is continuously precipitated can have larger fluctuation every time the suspension system is sampled, so that the dilution result lacks reproducibility, and the reliability and the efficiency of detection are further weakened. Therefore, the existing HPLC-based method is difficult to realize the rapid and accurate determination of the beta-CD content in the high-concentration feed liquid before recrystallization. Disclosure of Invention In view of the problems in the prior art, the present invention provides a method for detecting β -CD by changing the assay conditions such that the detectable concentration range is increased to 15wt%. In order to achieve the above purpose, the present invention adopts the following technical scheme. A method for detecting the content of beta-CD comprises the steps of raising the temperature of a feed liquid containing beta-CD to not lower than 65 ℃ and lower than 85 ℃, clathrating phenolphthalein under the condition of heat preservation, and detecting the content of beta-CD in the suspension feed liquid by reducing the color development degree of the phenolphthalein in an alkaline environment. Specifically, the method