Method for determining purity of glucosamine sulfate and sodium chloride double salt

Abstract

The invention relates to the field of glucosamine sulfate and sodium chloride double salt detection, in particular to a glucosamine sulfate and sodium chloride double salt purity determination method. According to the glucosamine sulfate and sodium chloride double salt purity determination method provided by the invention, simple chemical reagents and medicines and simple chemical instruments are used, and through simple operation, components which are difficult to separate by a conventional method can be effectively separated and detected, so that the accurate glucosamine sulfate and sodium chloride double salt purity is obtained. The detection method is low in detection cost, simple and easy to operate, capable of quickly and accurately knowing the detection result, unlimited in applicable environment and capable of being popularized in places such as factories.

Description

Technical Field

[0001] The invention relates to the field of biomedical purity detection, and in particular to a method for determining the purity of glucosamine sulfate sodium chloride complex salt. Background Art

[0002] Glucosamine sulfate sodium chloride complex salt is an antipyretic, analgesic and anti-inflammatory drug used in the treatment of primary and secondary osteoarthritis. Its structural formula is shown in the figure below:

[0003]

[0004] In the production process of glucosamine sulfate sodium chloride double salt, glucosamine hydrochloride and sodium sulfate need to be combined to form a double salt. Although glucosamine hydrochloride can also be used to treat primary and secondary osteoarthritis, it has certain gastrointestinal irritation and may cause gastrointestinal discomfort to some people who take it. Therefore, it is necessary to establish quality control for the purity of glucosamine sulfate sodium chloride double salt to avoid or reduce adverse drug reactions.

[0005] In addition, if glucosamine hydrochloride and sodium sulfate are mixed evenly in a physical manner according to a certain ratio, the mixture (hereinafter referred to as the mixture) obtained, because it exists in the form of glucosamine cations, chloride ions, sulfate ions, and sodium ions after being dissolved in conventional solvents, which is completely consistent with glucosamine sulfate sodium chloride double salt, the mixture can also meet all the quality inspection indicators of glucosamine sulfate sodium chloride double salt, and it is likely to be illegally used as glucosamine sulfate sodium chloride double salt, which is a counterfeit and inferior product and poses a danger to the life and health of the user population. Therefore, it is necessary to conduct quality control on the purity of glucosamine sulfate sodium chloride double salt to identify counterfeit and inferior drugs. There are two conventional development ideas in the prior art:

[0006] (1) The three components of glucosamine sulfate sodium chloride double salt, glucosamine hydrochloride, and sodium sulfate are separated and tested. However, since the three components all have the same groups or ions and similar physical and chemical properties, it is extremely difficult to separate and test them at the same time.

[0007] (2) The biggest difference between glucosamine sulfate sodium chloride double salt, glucosamine hydrochloride and sodium sulfate lies in the difference in crystal form. Infrared spectroscopy or X-ray diffraction can be used to find characteristic absorption peaks, thereby developing analytical methods for purity detection. However, due to the same characteristic groups and ions among the three, it is extremely difficult to screen for characteristic peaks that meet the requirements. At the same time, the inspection equipment for this method is also relatively expensive.

[0008] Therefore, it is necessary to develop an analytical method that is simple to operate, low in cost, and can effectively separate and detect, so as to control the purity of glucosamine sulfate sodium chloride double salt. Summary of the invention

[0009] In view of the existing technical problems, the present invention aims to provide a method for determining the purity of glucosamine sulfate sodium chloride complex salt, which has low detection cost, is simple and easy to operate, can quickly and accurately know the detection results, is not limited to the applicable environment, and can be popularized in factories and other places.

[0010] The invention discloses a method for determining the purity of glucosamine sulfate sodium chloride double salt, comprising the following steps:

[0011] (1) weighing finely ground glucosamine sulfate sodium chloride double salt and adding it to a centrifuge tube, then adding a separation liquid to the centrifuge tube for centrifugation, taking out the centrifuge tube after the centrifugation is completed and letting it stand, and obtaining a centrifuge separation liquid after the insoluble matter in the centrifuge tube is completely precipitated and the floating matter is completely floated;

[0012] (2) adding deionized water to the surface of the liquid along the wall of the centrifuge tube in step (1), absorbing the upper layer of liquid and floating matter after standing, and discarding them; repeating the above steps until the floating matter is completely removed;

[0013] (3) Transfer all the separation liquid and precipitate in the centrifuge tube to a weighing bottle, add separation liquid to wash the centrifuge tube, and combine the washing liquid into the same weighing bottle until the precipitate is completely transferred;

[0014] (4) Evaporate the weighing bottle obtained in step (3) in a water bath, add deionized water to dissolve the residue, transfer all of it to a 25 ml colorimetric tube, add deionized water to wash the weighing bottle, repeat the washing several times, and combine the washing liquid into the same colorimetric tube as the test sample tube;

[0015] (5) Weigh 100 mg of anhydrous sodium sulfate into a 100 ml bottle, add deionized water to dissolve and dilute to the mark on the 100 ml bottle, shake well, and use as the stock solution; measure different amounts of the stock solution into 25 ml colorimetric tubes as a series of control tubes;

[0016] (6) Add barium chloride solution and hydrochloric acid solution to the test tube and a series of control tubes, respectively, dilute to the scale with deionized water, shake well, let stand for 10 minutes, shake well, place on a black background, observe from the top of the colorimetric tube downward, and compare to obtain the purity of glucosamine sulfate sodium chloride complex salt.

[0017] Preferably, in step (1), the separation liquid is one halogenated alkane or a mixture of several halogenated alkanes.

[0018] Preferably, in step (1), the density of the separation liquid is 2 to 2.5 g / cm 3 .

[0019] Preferably, the halogenated alkane is dibromomethane or a dibromomethane solution with a mass fraction of no more than 28% of dichloromethane.

[0020] Preferably, in step (2), the centrifuge tube is left to stand for 1 to 2 minutes after centrifugation.

[0021] Preferably, in step (1), the centrifugal speed is 9000-10000 rpm.

[0022] Preferably, in step (1), the centrifugation time is 8 to 10 minutes.

[0023] Preferably, in step (6), the mass fraction of the barium chloride solution is 25%.

[0024] Preferably, in step (6), the mass fraction of the hydrochloric acid solution is 18.9%.

[0025] Preferably, in step (6), the amount of the stock solution pipetted is 1, 3, 5, 7, 9 ml, which is respectively equivalent to the free sodium sulfate content in the glucosamine sulfate sodium chloride double salt of 1, 3, 5, 7, 9%, which is respectively equivalent to the purity of the glucosamine sulfate sodium chloride double salt of 96%, 88%, 80%, 72%, 64%.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The method for measuring the purity of glucosamine sulfate sodium chloride complex salt provided by the present invention cleverly utilizes that the density of sodium sulfate is much greater than that of glucosamine sulfate sodium chloride complex salt, and then selects an organic solvent insoluble in both as a separation liquid, the density of the separation liquid is between the density of sodium sulfate and the density of glucosamine sulfate sodium chloride complex salt, and separates sodium sulfate and glucosamine sulfate sodium chloride complex salt into upper and lower layers of the separation liquid by centrifugation, and then removes the separation liquid and the glucosamine sulfate sodium chloride complex salt on the upper layer of the separation liquid, and what remains in the centrifuge tube is sodium sulfate, and then the concentration of sulfate ions is measured by turbidimetry using sodium sulfate, thereby obtaining the purity of glucosamine sulfate sodium chloride complex salt. The present invention selects halogenated alkane not only because this organic solvent meets the two characteristics of the above-mentioned separation liquid, but also because the boiling point of halogenated alkane is low, and it is easy to spin dry in the drying process after the transfer is completed, and it is not easy to have solvent residue. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 : Experimental results of comparative example 1

[0030] Figure 2 : Experimental results of Examples 1 to 3

[0031] Figure 3 : Comparative Example 2 Experimental Result Diagram DETAILED DESCRIPTION

[0032] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0033] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0034] Embodiment 1: A method for determining the purity of glucosamine sulfate sodium chloride double salt, comprising the following steps:

[0035] (1) Accurately weigh 100 mg of glucosamine sulfate sodium chloride complex salt and add it to a 5 ml centrifuge tube. Add 2 ml of dibromomethane and centrifuge at 9000 rpm for 8 min. Let the centrifuge tube stand upright for 3 minutes until the insoluble matter is completely precipitated and floated.

[0036] (2) Slowly add 2 ml of deionized water from the tube wall to the liquid surface, let it stand for 1 min, carefully aspirate the upper liquid (water layer) and discard it; repeat the above steps several times until the liquid surface is clear and no floating objects remain.

[0037] (3) Transfer all the dibromomethane and precipitate in the centrifuge tube to a weighing bottle, add an appropriate amount of dibromomethane to rinse the centrifuge tube, combine the washing liquid into the same weighing bottle, and repeat the rinsing until the precipitate is completely transferred.

[0038] (4) Evaporate the weighing bottle obtained in step (3) in a water bath, add an appropriate amount of deionized water to dissolve it, transfer all of it to a 25 ml colorimetric tube, add an appropriate amount of deionized water to wash the weighing bottle, repeat the washing three times, combine the washing liquid into the same colorimetric tube as the test sample tube, and prepare two test sample tubes in parallel according to steps (1) to (4).

[0039] (5) Accurately weigh 100 mg of anhydrous sodium sulfate and place it in a 100 ml bottle. Add water to dissolve and dilute to the mark. Shake well to prepare the stock solution. Accurately measure 1, 3, 5, 7, and 9 ml of the stock solution and place them in 25 ml colorimetric tubes as 1%, 3%, 5%, 7%, and 9% control tubes (equivalent to 96%, 88%, 80%, 72%, and 64% purity of glucosamine sulfate sodium chloride complex salt, respectively).

[0040] (6) Add 2.5 ml of 25% barium chloride solution and 1 ml of 18.9 mass fraction hydrochloric acid solution to the test tube and control tube respectively, dilute to the scale with water, shake well, let stand for 10 min, shake well, place on a black background, and observe and compare from the top of the colorimetric tube.

[0041] Among them, the glucosamine sulfate sodium chloride complex salt used in step (1) is sourced from Zhejiang Hisun Pharmaceutical Co., Ltd., with batch number 9051021N230501; the anhydrous sodium sulfate used in step (5) is sourced from Sinopharm Chemical Reagent Co., Ltd., with batch number 20180126, and the grade is analytically pure.

[0042] Embodiment 2: A method for determining the purity of glucosamine sulfate sodium chloride double salt, comprising the following steps:

[0043] (1) Accurately weigh 100 mg of glucosamine sulfate sodium chloride complex salt and add it to a 5 ml centrifuge tube. Add 2 ml of dibromomethane and centrifuge at 9500 rpm for 9 min. Let the centrifuge tube stand upright for 4 minutes until the insoluble matter is completely precipitated and floated.

[0044] (2) Slowly add 2 ml of deionized water from the tube wall to the liquid surface, let it stand for 1.5 min, carefully aspirate the upper liquid (water layer) and discard it; repeat the above steps several times until the liquid surface is clear and no floating objects remain.

[0045] The remaining steps are the same as those in Example 1.

[0046] Embodiment 3: A method for determining the purity of glucosamine sulfate sodium chloride double salt, comprising the following steps:

[0047] (1) Accurately weigh 100 mg of glucosamine sulfate sodium chloride complex salt and add it to a 5 ml centrifuge tube. Add 2 ml of dibromomethane and centrifuge at 10,000 rpm for 10 min. Let the centrifuge tube stand upright for 5 minutes until the insoluble matter is completely precipitated and floated.

[0048] (2) Slowly add 2 ml of deionized water from the tube wall to the liquid surface, let it stand for 2 minutes, carefully aspirate the upper liquid (water layer) and discard it; repeat the above steps several times until the liquid surface is clear and no floating objects remain.

[0049] The remaining steps are the same as those in Example 1.

[0050] Comparative Example 1: A linear test was performed for the determination method, and the specific steps are as follows:

[0051] (1) Accurately weigh 100 mg of anhydrous sodium sulfate into a 100 ml bottle, add deionized water to dissolve and dilute to the mark, shake well, and use this as the stock solution; accurately measure 1, 3, 5, 7, and 9 ml of the stock solution into 25 ml colorimetric tubes, respectively, as 1%, 3%, 5%, 7%, and 9% control tubes.

[0052] (2) Add 2.5 ml of 25% barium chloride solution and 1 ml of dilute hydrochloric acid to the 1%, 3%, 5%, 7%, and 9% control tubes, respectively. Dilute to the mark with water, shake well, let stand for 10 min, shake well, place on a black background, and observe and compare from the top of the colorimetric tube.

[0053] The source of anhydrous sodium sulfate used in step (1) is the same as that in Example 1.

[0054] Comparative Example 2: For the determination method, an accuracy test was conducted. According to the test results of Example 3, 4% sodium sulfate was added to the test tube and then the determination was conducted. The specific steps are as follows:

[0055] (1) Accurately weigh 100 mg of glucosamine sulfate sodium chloride complex salt and add it to a 5 ml centrifuge tube. Then accurately weigh 4 mg of anhydrous sodium sulfate and add 2 ml of dibromomethane. Centrifuge at 10,000 rpm for 10 min. Stand the centrifuge tube upright for several minutes until the insoluble matter is completely precipitated and floats.

[0056] (2) Slowly add 2 ml of deionized water from the tube wall to the liquid surface, let it stand for 1 min, carefully aspirate the upper liquid (water layer) and discard it; repeat the above steps several times until the liquid surface is clear and no floating objects remain.

[0057] (3) Transfer all the dibromomethane and precipitate in the centrifuge tube to a weighing bottle, add an appropriate amount of dibromomethane to rinse the centrifuge tube, combine the washing liquid into the same weighing bottle, and repeat the rinsing until the precipitate is completely transferred.

[0058] (4) Evaporate the weighing bottle obtained in step (3) in a water bath, add an appropriate amount of deionized water to dissolve it, transfer all of it to a 25 ml colorimetric tube, add an appropriate amount of deionized water to wash the weighing bottle, repeat the washing three times, combine the washing liquid into the same colorimetric tube as the test sample tube, and prepare 6 test sample tubes in parallel according to steps (1) to (4).

[0059] (5) Accurately weigh 100 mg of anhydrous sodium sulfate and place it in a 100 ml bottle. Add water to dissolve and dilute to the mark. Shake well to prepare the stock solution. Accurately measure 1, 3, 5, 7, and 9 ml of the stock solution and place them in 25 ml colorimetric tubes as 1%, 3%, 5%, 7%, and 9% control tubes.

[0060] (6) Add 2.5 ml of 25% barium chloride solution and 1 ml of 18.9 mass fraction hydrochloric acid solution to the test tube and control tube respectively, dilute to the scale with water, shake well, let stand for 10 min, shake well, place on a black background, and observe and compare from the top of the colorimetric tube.

[0061] The experimental results of Examples 1 to 3 are shown in the attached Figure 2 The results of comparative example 1 are shown in the attached Figure 1 The results of comparative example 2 are shown in the attached Figure 3 . Figure 1 It can be seen that the colors in the 1%, 3%, 5%, 7%, and 9% control tubes are clearly distinguishable and can be identified by the naked eye, indicating that the linearity of this method is good. Figure 2 It can be seen that the colors of the six test tubes in Examples 1 to 3 are consistent, all darker than the 3% control tube and lighter than the 5% control tube. It is inferred that the free sodium sulfate content in this batch of glucosamine sulfate sodium chloride double salt is about 4%, and the repeatability of this method is good. Figure 3 It can be seen that the colors of the 6 test tubes are consistent, all darker than the 7% control tube, and all lighter than the 9% control tube. It is speculated that the test result after adding 4% sodium sulfate to the test sample is about 8%, which is consistent with the test results of Examples 1 to 3. The accuracy of this method is good.

[0062] Comparative Example 3: Based on the determination method, the effect of separation liquid density on separation results was tested. The specific operation is as follows:

[0063] (1) Accurately weigh 100 mg of glucosamine sulfate sodium chloride complex salt and add it to a 5 ml centrifuge tube. Add 2 ml of a 28% methylene bromide solution (density about 2.0 g / cm 3 ), centrifuge at 10000rpm for 10min, and let the centrifuge tube stand upright for 25min until the insoluble matter is completely precipitated and floated.

[0064] (2) Accurately weigh 100 mg of glucosamine sulfate sodium chloride complex salt and add it to a 5 ml centrifuge tube. Add 2 ml of a 45% methylene chloride solution (density of about 1.8 g / cm 3 ), centrifuge at 10000rpm for 10min, let the centrifuge tube stand upright for 30min, insoluble matter precipitates, and no floating matter is observed on the upper layer of the separation liquid.

[0065] It can be seen from Comparative Example 3 that due to the reduced density of the separation liquid, the separation liquid can no longer effectively separate sodium sulfate from glucosamine sulfate sodium chloride double salt, and thus the purity of glucosamine sulfate sodium chloride double salt cannot be accurately determined.

[0066] Comparative Example 4: In terms of the determination method, a separation funnel is used to separate glucosamine sulfate sodium chloride double salt and sodium sulfate, and the specific design is as follows:

[0067] Accurately weigh 100 mg of glucosamine sulfate sodium chloride complex salt, add it to a separatory funnel, add 50 ml of dibromomethane, shake to evenly disperse the test sample, let it stand for several hours, and after the precipitation is complete, use a separatory funnel to take out the precipitate and part of the dibromomethane into a weighing bottle, and then conduct the test as in Example 3.

[0068] The source of the glucosamine sulfate sodium chloride double salt used is the same as that in Example 1.

[0069] It was observed during the experiment that during static separation, only a small amount of insoluble matter could be precipitated over time, while more insoluble matter was suspended in dibromomethane and could not be precipitated smoothly even after being left to stand for more than 20 hours. Therefore, the experiment was terminated and this separation method was abandoned.

[0070] Comparative Example 5: With regard to the determination method, the purity of glucosamine sulfate sodium chloride double salt was detected by the weight difference method, and the specific design is as follows:

[0071] (1) Accurately weigh 1 g (W) of glucosamine sulfate sodium chloride complex salt and add it to a 20 ml centrifuge tube. Add 15 ml of dibromomethane and centrifuge at 4000 rpm for 20 min. Stand the centrifuge tube upright for several minutes until the precipitation is complete.

[0072] (2) Slowly add 4 ml of water from the tube wall to the liquid surface, let it stand for 1-2 minutes, carefully absorb the upper liquid (water layer) and discard it.

[0073] (3) Repeat "step (2)" several times until the liquid surface is clear and no floating objects remain. Repeat "step (2)" twice more and use absorbent paper to absorb all the residual water on the upper layer to ensure that no floating objects remain.

[0074] (4) Transfer all the dibromomethane and precipitate in the centrifuge tube to a weighing bottle, add an appropriate amount of dibromomethane to rinse the centrifuge tube, combine the washing liquid into the same weighing bottle, and repeat the rinsing if necessary until the precipitate is completely transferred.

[0075] (5) The weighing bottle in step (4) was evaporated in a water bath, and an appropriate amount of water was added to dissolve it. The whole amount was transferred to a conical flask, and 2.5 ml of 25% barium chloride solution and 1 ml of dilute hydrochloric acid were added and shaken. The mixture was allowed to stand for 10 min. A G4 vertical sintered funnel (W) was used to weigh the mixture at 105°C. 1 ) Filter, add appropriate amount of water to wash the conical flask 3 times, combine the washings and filter, and continue to dry the G4 vertical melting funnel at 105℃ to constant weight (W 2 ).

[0076] (6) According to the weight difference (W2- W 1 ) to obtain the weight of the precipitate (barium sulfate), according to the formula (1-(W 2 -W 1 ) / W / 233.39*573.2)*100% to calculate the purity of glucosamine sulfate sodium chloride double salt.

[0077] Wherein, the source of glucosamine sulfate sodium chloride double salt used in step (1) is the same as that in Example 1.

[0078] During the test: When it came to step (5), the filtrate was found to be turbid. It was possible that the pore size of the filter element of the G4 vertical melting funnel was too large to filter and separate the produced barium sulfate. After that, we tried to use filter paper to filter, but found that it was difficult to keep the weight constant. The filter membranes of other materials were also difficult to withstand the high temperature of 105°C. Therefore, this determination method was abandoned.

[0079] Comparative Example 6: With regard to the determination method, the purity of glucosamine sulfate sodium chloride double salt was detected by weight difference method, and the specific design is as follows:

[0080] (1) Accurately weigh 1 g (W) of glucosamine sulfate sodium chloride complex salt and add it to a 20 ml centrifuge tube. Add 15 ml of dibromomethane and centrifuge at 4000 rpm for 20 min. Stand the centrifuge tube upright for several minutes until the precipitation is complete.

[0081] (2) Slowly add 4 ml of water from the tube wall to the liquid surface, let it stand for 1-2 minutes, carefully absorb the upper liquid (water layer) and discard it.

[0082] (3) Repeat "step (2)" several times until the liquid surface is clear and no floating objects remain. Repeat "step (2)" twice more and use absorbent paper to absorb all the residual water on the upper layer to ensure that no floating objects remain.

[0083] (4) Transfer the dibromomethane and the precipitate in the centrifuge tube to a constant weight weighing bottle (W) pre-set at 105°C. 1 ), add appropriate amount of dibromomethane to rinse the centrifuge tube, combine the washing liquid into the same weighing bottle, and repeat the rinsing if necessary until the precipitate is completely transferred.

[0084] (5) The weighing bottle in step (4) is further dried at 105°C until constant weight (W 2 ), according to the weight difference (W 2 -W 1 ) to obtain the weight of the precipitate (sodium sulfate), according to the formula (1-(W 2 -W 1 ) / W / 142.06*573.2)*100% to calculate the purity of glucosamine sulfate sodium chloride double salt.

[0085] Wherein, the source of glucosamine sulfate sodium chloride double salt used in step (1) is the same as that in Example 1.

[0086] The experimental data of Comparative Example 6 are shown in the following table:

[0087]

[0088] From the experimental data in the above table, it can be seen that 6 parallel measurements were performed with an RSD>10%, indicating that the repeatability of this measurement method is poor.

[0089] In summary, Examples 1 to 3 are the most representative implementations of the method of the present invention. Examples 1 to 3, Comparative Example 1 and Comparative Example 2 jointly completed a simple methodological verification process, indicating that the linearity, repeatability and accuracy of the present method are good. Since the detection method is the sulfate test method commonly used in the industry, its sensitivity and specificity are also clearly guaranteed. In addition, based on the experimental results of Examples 1 to 3, it is estimated that the purity of this batch of glucosamine sulfate sodium chloride double salt is in the range of 80% to 88%. In Comparative Example 3, it can be seen that the density of the separation liquid needs to be between 2 and 2.5 g / cm 3 There will be a good separation effect. In Comparative Example 4, since centrifugation cannot be performed in the separatory funnel, the difficulty of separating the components in the test sample increases dramatically, and the separation and detection cannot be successfully performed. In Comparative Example 5, since the generated barium sulfate cannot be accurately weighed, quantitative determination cannot be performed. In Comparative Example 6, since it is inevitable that there is a trace of sodium chloride sulfate glucosamine double salt remaining in various forms, the residual amount directly causes the measured amount of sodium sulfate to be high, so that the purity result of the determination is low, and since the residual level cannot be guaranteed to be consistent, the RSD of the 6 results of parallel determination is also high, and reproducibility and accuracy cannot be guaranteed. Therefore, the method provided by the present invention is easy to operate, safe and simple to use reagents, relatively low requirements for experimental equipment, only slightly higher requirements for the technical level of the test personnel, with good accuracy and reproducibility, can meet the daily detection requirements of the purity of sodium chloride sulfate glucosamine double salt.

[0090] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention.

Claims

1. A method for determining the purity of glucosamine sulfate sodium chloride double salt, characterized in that: The following steps are involved: (1) weighing finely ground glucosamine sulfate sodium chloride double salt and adding it to a centrifuge tube, then adding a separation liquid to the centrifuge tube for centrifugation, taking out the centrifuge tube after the centrifugation is completed and letting it stand, and obtaining a centrifuge separation liquid after the insoluble matter in the centrifuge tube is completely precipitated and the floating matter is completely floated; (2) adding deionized water to the surface of the liquid along the wall of the centrifuge tube in step (1), absorbing the upper layer of liquid and floating matter after standing, and discarding them; repeating the above steps until the floating matter is completely removed; (3) Transfer all the separation liquid and precipitate in the centrifuge tube to a weighing bottle, add separation liquid to wash the centrifuge tube, and combine the washing liquid into the same weighing bottle until the precipitate is completely transferred; (4) Evaporate the weighing bottle obtained in step (3) in a water bath, add deionized water to dissolve the residue, transfer all of it to a 25 ml colorimetric tube, add deionized water to wash the weighing bottle, repeat the washing several times, and combine the washing liquid into the same colorimetric tube as the test sample tube; (5) Weigh 100 mg of anhydrous sodium sulfate into a 100 ml bottle, add deionized water to dissolve and dilute to the mark on the 100 ml bottle, shake well, and use as the stock solution; measure different amounts of the stock solution into 25 ml colorimetric tubes as a series of control tubes; (6) Add barium chloride solution and hydrochloric acid solution to the test tube and a series of control tubes, respectively, dilute to the scale with deionized water, shake well, let stand for 10 minutes, shake well, place on a black background, observe from the top of the colorimetric tube downward, and compare to obtain the purity of glucosamine sulfate sodium chloride complex salt.

2. A method for determining the purity of glucosamine sulfate sodium chloride double salt according to claim 1, characterized in that: In step (1), the separation liquid is a halogenated alkane or a mixture of several halogenated alkanes.

3. A method for measuring the purity of glucosamine sulfate sodium chloride double salt according to claim 1, characterized in that: In step (1), the density of the separation liquid is 2 to 2.5 g / cm 3 .

4. A method for measuring the purity of glucosamine sulfate sodium chloride double salt according to claim 2, characterized in that: The halogenated alkane is dibromomethane or a dibromomethane solution containing dichloromethane with a mass fraction of no more than 28%.

5. A method for measuring the purity of glucosamine sulfate sodium chloride double salt according to claim 1, characterized in that: In step (2), the centrifuge tube is left to stand for 1 to 2 minutes after centrifugation.

6. A method for determining the purity of glucosamine sulfate sodium chloride double salt according to claim 1, characterized in that: In step (1), the centrifugal speed is 9000-10000 rpm.

7. A method for determining the purity of glucosamine sulfate sodium chloride double salt according to claim 1, characterized in that: In step (1), the centrifugation time is 8 to 10 minutes.

8. A method for determining the purity of glucosamine sulfate sodium chloride double salt according to claim 1, characterized in that: In step (6), the mass fraction of the barium chloride solution is 25%.

9. A method for determining the purity of glucosamine sulfate sodium chloride double salt according to claim 1, characterized in that: In step (6), the mass fraction of the hydrochloric acid solution is 18.9%.

10. A method for determining the purity of glucosamine sulfate sodium chloride double salt according to claim 1, characterized in that: In step (6), the amount of the stock solution pipetted is 1, 3, 5, 7, and 9 ml, which is respectively equivalent to the free sodium sulfate content in the glucosamine sulfate sodium chloride double salt of 1, 3, 5, 7, and 9%, which is respectively equivalent to the purity of the glucosamine sulfate sodium chloride double salt of 96%, 88%, 80%, 72%, and 64%.

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