A method for determining aluminum salt in peritoneal dialysis fluid by fluorescence spectrophotometry
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XI AN RENALYSIS MEDICAL TECH CO LTD
- Filing Date
- 2020-12-09
- Publication Date
- 2026-07-03
AI Technical Summary
Existing technologies for determining aluminum salts in peritoneal dialysis fluid are unstable and have poor reproducibility. They also fail to effectively handle impurity ions that may interfere with the determination, resulting in high detection limits and making it difficult to achieve precise control of the aluminum content in the product.
The fluorescence spectrophotometer method was used to eliminate interference from transition metal impurity ions by using the complex formed by α-tholytein and Al3+ in ethyl acetate, combined with extraction with concentrated hydrochloric acid and 1,1-dimethylacetone. Specific measurement parameters such as photomultiplier voltage, PMT gain, and integration time were specified to optimize the sample preparation method and measurement parameters.
This method improves the stability and reproducibility of aluminum salt determination, meets the quality inspection requirements for peritoneal dialysis fluid products, achieves precise control of aluminum content, and ensures product quality and safety.
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Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of aluminum salt determination in injectable products in the pharmaceutical industry, specifically relating to a method for determining aluminum salts in peritoneal dialysis fluid using a fluorescence spectrophotometer. Background Technology
[0002] Peritoneal dialysis fluid is a clear, sterile solution free of pyrogens and endotoxins, with a suitable pH, prepared from glucose, sodium lactate, sodium chloride, calcium chloride, and magnesium chloride. Clinically, it can be used to treat acute or chronic renal failure, drug poisoning, refractory heart failure, and severe electrolyte disturbances such as hyperkalemia. Since water is the only solvent in peritoneal dialysis fluid, and trace amounts of aluminum are unavoidable, aluminum in normal individuals is mainly ingested through the digestive tract, with most excreted through the intestines and a small portion absorbed into the bloodstream and excreted by the kidneys. However, in uremia patients, not only is aluminum excretion significantly reduced, but the amount absorbed through the digestive tract is also increased compared to normal individuals, thus easily leading to aluminum accumulation and poisoning in the body. Related studies show that renal osteodystrophy, anemia, and encephalopathy during dialysis are all related to trace amounts of elemental aluminum. Multiple studies stipulate that the aluminum content in peritoneal dialysis fluid products must be maintained below 10 ppb. Therefore, developing aluminum salt analysis methods with low detection limits, high accuracy, and high precision is a key factor in ensuring product quality.
[0003] The Chinese Pharmacopoeia and existing national standards do not record any methods for testing aluminum salts. To achieve strict quality control of peritoneal dialysis fluid products and meet higher product registration requirements, the existing analytical method is derived from the European Pharmacopoeia, version 9.0. The procedure is as follows: Take 600 ml of the test solution, adjust the pH to 6.0 with 0.1 M sodium hydroxide, and add 10 ml of acetate buffer (pH 6.0) to prepare the test solution. Mix 10 ml of acetate buffer (pH 6.0) and 10 ml of water to prepare the blank solution. Mix 3 mL of standard aluminum solution (2 ppm Al), 10 mL of acetate buffer (pH 6.0), and 9 mL of water to prepare the reference solution. Extract the test solution, reference solution, and blank solution three times (20 ml, 20 ml, 10 ml) with chloroform solution of 8-hydroxyquinoline (0.5%). Combine the extracts in a 50 ml volumetric flask, dilute to the mark with chloroform, and mix well. The result is obtained by measuring the aluminum salt (2.4.17) and fluorescence method (2.2.21) at an excitation wavelength of 392 nm and an emission wavelength of 518 nm.
[0004] Existing methods for testing aluminum salts in peritoneal dialysis fluid exhibit poor reproducibility and data instability. Abnormally large negative values frequently appear during the determination of samples and aluminum control solutions of a certain concentration. During method validation, the linear correlation coefficient was less than 0.995, indicating no linear correlation, while general methods require a linear correlation coefficient of at least 0.999 to demonstrate good linearity. Blank sample data rarely stabilized near 0; the standard deviation of 10 blank sample determinations was approximately 200, leading to a high detection limit and hindering precise control of the product's aluminum content. Robustness (solution stability) tests on 12 batches of samples revealed abnormally large negative values in some samples, and significant fluctuations in data between two determinations, with RD% values exceeding the standard limit by 15%, indicating poor stability. Furthermore, the existing method does not address potential interfering impurity ions in the samples and lacks specific requirements for other measurement parameters besides wavelength, resulting in poor reproducibility and stability, and ultimately failing method validation. Therefore, a method for aluminum salt determination with good reproducibility, stability, and robust validation is needed.
[0005] The measurement data for the above issues are shown in the table below:
[0006] Table 1 shows the linearity results obtained using existing methods.
[0007]
[0008] Table 2 shows the detection limits determined using existing methods.
[0009]
[0010] Table 3 shows the durability results of 12 batches of samples determined using existing methods.
[0011]
[0012] Summary of the Invention
[0013] The purpose of this invention is to provide a method for determining aluminum salts in peritoneal dialysis fluid using a fluorescence spectrophotometer, solving the problems of unstable results and poor reproducibility in existing technologies for determining aluminum salts. Through research and testing of sample preparation methods and specific measurement parameters, this invention has discovered that α-dextrin (full name 1,3,6-trihydroxy-7-methoxy-2,8-bis(3-methyl-2-butenyl)-9H-oxanthracene-9-one) and Al... 3+The complex formed in ethyl acetate exhibits excellent stability and strong fluorescence intensity. Furthermore, treatment of the sample with concentrated hydrochloric acid and extraction with 1,1-dimethylacetone (MIPK) eliminates interference from transition metal impurities. Specific measurement parameters were also defined. The new method demonstrated good methodological validation and meets the requirements for aluminum salt testing in peritoneal dialysis fluid products.
[0014] The specific implementation process of this invention is as follows:
[0015] A method for determining aluminum salts in peritoneal dialysis fluid using a fluorescence spectrophotometer includes the following steps:
[0016] Step 1, Preparation of the test solution
[0017] Add concentrated hydrochloric acid to the peritoneal dialysis fluid, then extract with 1,1-dimethylacetone, collect the aqueous phase and adjust the pH to 6.0, add acetate buffer, and then extract with ethyl acetate solution of α-dextrin. Collect and combine the ethyl acetate extracts into a 50 ml volumetric flask, dilute to the mark with ethyl acetate, and use as the test solution.
[0018] Step 2, Preparation of blank solution
[0019] Add concentrated hydrochloric acid to water for injection, then extract with 1,1-dimethylacetone, collect the aqueous phase and adjust the pH to 6.0, add acetate buffer, and then extract with ethyl acetate solution of α-dextrin. Collect and combine the ethyl acetate extracts into a 50 ml volumetric flask, dilute to the mark with ethyl acetate, and use as a blank solution.
[0020] Step 3, Preparation of the reference solution
[0021] Preparation of solvent a: Add concentrated hydrochloric acid to water for injection, then extract with 1,1-dimethylacetone, collect the aqueous phase and adjust the pH to 6.0, add acetate buffer to obtain solvent a;
[0022] Preparation process of reference solution:
[0023] Accurately measure 2 ml of 1000 ppm aluminum single element standard solution into a 100 ml volumetric flask, dilute to the mark with solvent a, and shake well to prepare the reference stock solution; before use, take 1.5 ml of the reference stock solution into a 50 ml volumetric flask, dilute to the mark with solvent a, and shake well to prepare solution ①; accurately measure 10 ml of solution ①, extract three times with ethyl acetate solution of α-dextrin, collect and combine the ethyl acetate extracts into a 50 ml volumetric flask, and dilute to the mark with ethyl acetate to prepare the reference solution;
[0024] Step 4, Fluorescence spectrophotometric detection process
[0025] The prepared test solution, blank solution, and reference solution were measured by fluorescence spectrophotometry at an excitation wavelength of 386 nm, an emission wavelength of 523 nm, a photomultiplier voltage of 400 V, a PMT gain of ×1, an integration time of 700 ms, and a slit width of 5 nm. The results were then calculated.
[0026] Further, the specific operating steps of step 1 are as follows: Take 600 ml of peritoneal dialysis fluid and place it in a 1 L separatory funnel. Add 20 ml of concentrated hydrochloric acid, shake well, cool, and extract with 10 ml of 1,1-dimethylacetone for 5 min. Allow the mixture to stand and separate into layers, collect the aqueous phase in a 1 L beaker, adjust the pH to 6.0 with sodium hydroxide, add 10 ml of acetate buffer, transfer to a 1 L separatory funnel, and perform three extractions with ethyl acetate solution of α-dextrin. Collect and combine the ethyl acetate extracts in a 50 ml volumetric flask, dilute to the mark with ethyl acetate, and use as the test solution.
[0027] Further, the specific operating steps of step 2 are as follows: Take 600 ml of water for injection and place it in a 1 L separatory funnel. Add 20 ml of concentrated hydrochloric acid, shake well, and cool. Extract with 10 ml of 1,1-dimethylacetone for 5 min. Allow the aqueous phase to stand and separate into layers, collect it in a 1 L beaker, adjust the pH to 6.0 with sodium hydroxide, add 10 ml of acetate buffer, and transfer it to a 1 L separatory funnel. Extract three times with ethyl acetate solution of α-dextrin. Collect and combine the ethyl acetate extracts in a 50 ml volumetric flask, dilute to the mark with ethyl acetate, and use as a blank solution.
[0028] Furthermore, in step 3, the specific process for preparing solvent a is as follows: Take 600 ml of water for injection, place it in a 1 L separatory funnel, add 20 ml of concentrated hydrochloric acid, shake well, cool, extract with 10 ml of 1,1-dimethylacetone for 5 min, let stand to separate the layers, collect the aqueous phase in a 1 L beaker, adjust the pH to 6.0 with sodium hydroxide, and add 10 ml of acetate buffer to obtain solvent a.
[0029] Furthermore, in steps 1, 2, and 3, the pH of the acetate buffer solution is 6.0.
[0030] Furthermore, in steps 1, 2, and 3, the preparation process of the ethyl acetate solution of α-dextrin is as follows: 5g of α-dextrin is dissolved in 1000ml of ethyl acetate to obtain the ethyl acetate solution of α-dextrin.
[0031] In this invention, fluorescence intensity is abbreviated as INT.
[0032] The working principle of the fluorescence spectrophotometer in this invention is as follows: Ultraviolet and blue-violet light emitted by a high-pressure mercury lamp or xenon lamp are filtered and irradiated into the sample cell, exciting the fluorescent substances in the sample to emit fluorescence. After filtering and reflection, the fluorescence is received by a photomultiplier tube and then displayed in graphical or digital form. The generation of fluorescence occurs when molecules in their ground state under normal conditions absorb excitation light and become excited. These excited molecules are unstable and release some energy as light during their return to the ground state, thus producing fluorescence. The basic structure includes five parts: a light source, an excitation monochromator, an emission monochromator, a sample chamber, and a detector.
[0033] The positive effects of this invention:
[0034] (1) α-Tyropoietin and Al 3+ The complex formed in ethyl acetate exhibits strong fluorescence intensity and stability.
[0035] (2) The sample was treated with concentrated hydrochloric acid and extracted with 1,1-dimethylacetone (MIPK) to eliminate interference from transition metal impurity ions and improve the stability of the determination.
[0036] (3) The method of the present invention adds the specification of special instrument parameters: photomultiplication voltage (400V), PMT gain (×1), integration time (700ms), and slit width (5nm).
[0037] (4) The method of this invention solves the problems of unstable and poor reproducibility in the determination of aluminum salts in the prior art. Moreover, the method has been well validated and meets the requirements for aluminum salt testing under the quality inspection of peritoneal dialysis fluid products, thereby achieving precise control over the quality of peritoneal dialysis fluid and improving product quality and safety. Attached Figure Description
[0038] Figure 1 Linear equations and correlation coefficients determined using existing methods;
[0039] Figure 2 This is a graph showing the full-wavelength excitation scan of the aluminum reference solution using the method of the present invention on a fluorescence spectrophotometer;
[0040] Figure 3 This is a graph showing the emission full-wavelength scan of the aluminum reference solution using the method of the present invention on a fluorescence spectrophotometer;
[0041] Figure 4 To determine the linear equation and correlation coefficient of the reference solution using the method of this invention. Detailed Implementation
[0042] The present invention will be further described below with reference to the embodiments.
[0043] To address the aforementioned problems and overcome the shortcomings of existing technologies, this invention studies and tests its sample preparation methods and measurement parameters. The study discovered that α-dextrin (full name 1,3,6-trihydroxy-7-methoxy-2,8-bis(3-methyl-2-butenyl)-9H-oxanthracene-9-one) and Al... 3+ The complex formed in ethyl acetate exhibits strong fluorescence intensity and stability. To eliminate interference from transition metal impurity ions, concentrated hydrochloric acid was added and the mixture was extracted with 1,1-dimethylacetone (MIPK). In addition to the measurement wavelength, specific instrument parameters were set: photomultiplication voltage (400V), PMT gain (×1), integration time (700ms), and slit width (5nm).
[0044] Example 1
[0045] The analytical method for determining aluminum salts in peritoneal dialysis fluid using fluorescence spectrophotometry as described in this embodiment includes the following steps:
[0046] Step 1, Preparation of the test solution
[0047] Take 600 ml of peritoneal dialysis fluid and place it in a 1 L separatory funnel. Add 20 ml of concentrated hydrochloric acid, shake well, and cool. Extract with 10 ml of 1,1-dimethylacetone (MIPK) for 5 min. Allow to stand and separate the layers, collecting the aqueous phase in a 1 L beaker. Adjust the pH to 6.0 with sodium hydroxide, and add 10 ml of acetate buffer (pH 6.0). Transfer to a 1 L separatory funnel and perform three extractions with an ethyl acetate solution of α-dextrin (20 ml for the first extraction, 20 ml for the second, and 10 ml for the third). Collect and combine the ethyl acetate extracts in a 50 ml volumetric flask, and dilute to the mark with ethyl acetate to obtain the test solution. The pH of the acetate buffer is 6.0. The preparation of the ethyl acetate solution of α-dextrin is as follows: dissolve 5 g of α-dextrin in 1000 ml of ethyl acetate to obtain the ethyl acetate solution of α-dextrin.
[0048] Step 2: Preparation of blank solution
[0049] Take 600 ml of water for injection and place it in a 1 L separatory funnel. Add 20 ml of concentrated hydrochloric acid, shake well, and cool. Extract with 10 ml of 1,1-dimethylacetone for 5 min. Allow to stand and separate the layers, collecting the aqueous phase in a 1 L beaker. Adjust the pH to 6.0 with sodium hydroxide, and add 10 ml of acetate buffer (pH 6.0). Transfer to a 1 L separatory funnel and perform three extractions with an ethyl acetate solution of α-dextrin (20 ml for the first extraction, 20 ml for the second, and 10 ml for the third). Collect and combine the ethyl acetate extracts in a 50 ml volumetric flask, and dilute to the mark with ethyl acetate to obtain a blank solution. The pH of the acetate buffer is 6.0. The preparation of the ethyl acetate solution of α-dextrin is as follows: dissolve 5 g of α-dextrin in 1000 ml of ethyl acetate to obtain an ethyl acetate solution of α-dextrin.
[0050] Step 3: Preparation of the reference solution
[0051] Solvent a preparation: Take 600 ml of water for injection and place it in a 1 L separatory funnel. Add 20 ml of concentrated hydrochloric acid, shake well, and cool. Extract with 10 ml of 1,1-dimethylacetone (MIPK) for 5 min. Allow to stand for separation and collect the aqueous phase in a 1 L beaker. Adjust the pH to 6.0 with sodium hydroxide and add 10 ml of acetate buffer (pH 6.0) to obtain the solution.
[0052] Accurately measure 2 ml of 1000 ppm aluminum single-element standard solution into a 100 ml volumetric flask, dilute to the mark with solvent a, and shake well to prepare the reference stock solution. Before use, take 1.5 ml of the reference stock solution into a 50 ml volumetric flask, dilute to the mark with solvent a, and shake well to prepare solution ①. Accurately measure 10 ml of solution ① and extract three times with an ethyl acetate solution of α-dextrin (20 ml for the first extraction, 20 ml for the second, and 10 ml for the third). Collect and combine the ethyl acetate extracts into a 50 ml volumetric flask, dilute to the mark with ethyl acetate to prepare the reference solution. The pH of the acetate buffer is 6.0. The preparation process of the ethyl acetate solution of α-dextrin is as follows: dissolve 5 g of α-dextrin in 1000 ml of ethyl acetate to obtain the ethyl acetate solution of α-dextrin.
[0053] Step 4: Detection by fluorescence spectrophotometry
[0054] The prepared test solution, blank solution, and reference solution were measured by fluorescence spectrophotometry (General Chapter 0405, Chinese Pharmacopoeia 2015 Edition) at an excitation wavelength of 386 nm, an emission wavelength of 523 nm, a photomultiplier voltage of 400 V, a PMT gain of ×1, an integration time of 700 ms, and a slit width of 5 nm. The results were then calculated.
[0055] Calculation formula:
[0056]
[0057] In the formula: I1 is the fluorescence intensity of the reference standard; I2 is the fluorescence intensity of the test sample.
[0058] Methodological validation of the method in this implementation:
[0059] (1) Maximum absorption wavelength
[0060] Take the reference solution and perform a full-wavelength scan of excitation and emission on a fluorescence spectrophotometer. The maximum excitation wavelength is 386 nm. See [link to relevant documentation]. Figure 2 The maximum emission wavelength is 523nm, see Figure 3 .
[0061] (2) Exclusivity
[0062] Fluorescence was measured on the negative control (blank solution) and the positive control (standard solution) according to the method. The result of the negative control was close to zero and differed from the result of the positive control by more than 1000 times, indicating good specificity.
[0063] (3) Linear
[0064] Linear solution stock solution: Accurately measure 20 ml of solution ① and extract three times with ethyl acetate solution of α-dextrin (20 ml, 20 ml, 10 ml). Collect and combine the ethyl acetate extracts into a 50 ml volumetric flask, and dilute to the mark with ethyl acetate.
[0065] Linear solutions: Accurately transfer 4 ml, 6 ml, 8 ml, 10 ml, and 15 ml of the linear solution stock solution into 20 ml volumetric flasks, dilute to the mark with ethyl acetate, and mix well to obtain linear solutions of 40%, 60%, 80%, 100%, and 150%. (Prepare two parallel aliquots)
[0066] The above linear solution was subjected to fluorescence determination according to the method, and the linear correlation coefficient r was obtained. 2 =0.9991, indicating good linearity. The results are shown in the table below:
[0067] Table 4. Linearity results of the method in this embodiment.
[0068]
[0069] (4) Limit of detection
[0070] According to the 2015 edition of the Chinese Pharmacopoeia, Part IV, General Chapter 0901: the limit of detection (LOD) is 3.3δ / S, where δ is the standard deviation of the blank response value and S is the slope of the calibration curve. The results are shown in the table below:
[0071] Table 5 shows the detection limit results of the method in this embodiment.
[0072]
[0073] (5) Durability (solution stability)
[0074] Preparation process of test solution 1-test solution 12
[0075] Take 600 ml of peritoneal dialysis fluid from 12 batches and place it in a 1 L separatory funnel. Add 20 ml of concentrated hydrochloric acid, shake well, cool, and extract with 10 ml of 1,1-dimethylacetone (MIPK) for 5 min. Allow to stand for separation, collect the aqueous phase in a 1 L beaker, adjust the pH to 6.0 with sodium hydroxide, add 10 ml of acetate buffer (pH 6.0), and transfer to a 1 L separatory funnel. Perform three extractions with an ethyl acetate solution of α-dextrin (20 ml for the first extraction, 20 ml for the second extraction, and 10 ml for the third extraction). Collect and combine the ethyl acetate extracts in a 50 ml volumetric flask, and dilute to the mark with ethyl acetate to obtain test solution 1-test solution 12. The pH of the acetate buffer is 6.0. The preparation process of the ethyl acetate solution of α-dextrin is as follows: dissolve 5 g of α-dextrin in 1000 ml of ethyl acetate to obtain the ethyl acetate solution of α-dextrin.
[0076] Twelve batches of test solutions were prepared and tested to examine their stability within 1 hour. The results showed that the RD% was less than 15%, meeting the standard requirements.
[0077] Results of continuous determination of 12 batches of test solution and stability results after 1 hour of standing.
[0078]
[0079] In summary, the specificity, linear range, detection limit, and robustness of the method of this invention all meet acceptable standards.
[0080] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.
Claims
1. A method for determining aluminum salts in peritoneal dialysis fluid by fluorescence spectrophotometry, characterized in that, Includes the following steps: Step 1, Preparation of the test solution Add concentrated hydrochloric acid to the peritoneal dialysis fluid, then extract with 1,1-dimethylacetone, collect the aqueous phase and adjust the pH to 6.0, add acetate buffer, and then extract with ethyl acetate solution of α-dextrin. Collect and combine the ethyl acetate extracts into a 50 ml volumetric flask, dilute to the mark with ethyl acetate, and use as the test solution. Step 2, Preparation of blank solution Add concentrated hydrochloric acid to water for injection, then extract with 1,1-dimethylacetone, collect the aqueous phase and adjust the pH to 6.0, add acetate buffer, and then extract with ethyl acetate solution of α-dextrin. Collect and combine the ethyl acetate extracts into a 50 ml volumetric flask, dilute to the mark with ethyl acetate, and use as a blank solution. Step 3, Preparation of the reference solution Preparation of solvent a: Add concentrated hydrochloric acid to water for injection, then extract with 1,1-dimethylacetone, collect the aqueous phase and adjust the pH to 6.0, add acetate buffer to obtain solvent a; Preparation process of reference solution: Accurately measure 2 ml of 1000 ppm aluminum single element standard solution into a 100 ml volumetric flask, dilute to the mark with solvent a, and shake well to prepare the reference stock solution; before use, take 1.5 ml of the reference stock solution into a 50 ml volumetric flask, dilute to the mark with solvent a, and shake well to prepare solution ①; accurately measure 10 ml of solution ①, extract three times with ethyl acetate solution of α-dextrin, collect and combine the ethyl acetate extracts into a 50 ml volumetric flask, and dilute to the mark with ethyl acetate to prepare the reference solution; Step 4, Fluorescence spectrophotometric detection process The prepared test solution, blank solution, and reference solution were measured by fluorescence spectrophotometry at an excitation wavelength of 386 nm, an emission wavelength of 523 nm, a photomultiplier voltage of 400 V, a PMT gain of ×1, an integration time of 700 ms, and a slit width of 5 nm. The results were then calculated.
2. The method for determining the aluminum salt in the peritoneal dialysis fluid using the fluorescence spectrophotometer method according to claim 1, characterized in that: Step 1: Take 600 ml of peritoneal dialysis fluid and place it in a 1 L separatory funnel. Add 20 ml of concentrated hydrochloric acid, shake well, and cool. Extract with 10 ml of 1,1-dimethylacetone for 5 min. Allow the layers to separate and collect the aqueous phase in a 1 L beaker. Adjust the pH to 6.0 with sodium hydroxide and add 10 ml of acetate buffer. Transfer the mixture to a 1 L separatory funnel and extract three times with ethyl acetate solution of α-dextrin. Collect and combine the ethyl acetate extracts in a 50 ml volumetric flask and dilute to the mark with ethyl acetate to obtain the test solution.
3. The method for determining aluminum salts in peritoneal dialysis fluid using a fluorescence spectrophotometer according to claim 1, characterized in that: Step 2: Take 600 ml of water for injection and place it in a 1 L separatory funnel. Add 20 ml of concentrated hydrochloric acid, shake well, and cool. Extract with 10 ml of 1,1-dimethylacetone for 5 min. Allow the aqueous phase to separate into layers and collect it in a 1 L beaker. Adjust the pH to 6.0 with sodium hydroxide and add 10 ml of acetate buffer. Transfer the mixture to a 1 L separatory funnel and extract three times with ethyl acetate solution of α-dextrin. Collect and combine the ethyl acetate extracts in a 50 ml volumetric flask and dilute to the mark with ethyl acetate to obtain a blank solution.
4. The method for determining the aluminum salt in the peritoneal dialysis fluid using the fluorescence spectrophotometer method according to claim 1, characterized in that: In step 3, the specific process for preparing solvent a is as follows: Take 600 ml of water for injection, place it in a 1 L separatory funnel, add 20 ml of concentrated hydrochloric acid, shake well, cool, extract with 10 ml of 1,1-dimethylacetone for 5 min, let stand to separate the layers, collect the aqueous phase in a 1 L beaker, adjust the pH to 6.0 with sodium hydroxide, and add 10 ml of acetate buffer to obtain solvent a.
5. The method for determining aluminum salts in peritoneal dialysis fluid using a fluorescence spectrophotometer according to claim 1, characterized in that: In steps 1, 2 and 3, the pH of the acetate buffer solution is 6.
0.
6. The method for determining the aluminum salt in the peritoneal dialysis fluid using the fluorescence spectrophotometer method according to claim 1, characterized in that: In steps 1, 2, and 3, the preparation process of the ethyl acetate solution of α-dextrin is as follows: 5g of α-dextrin is dissolved in 1000ml of ethyl acetate to obtain the ethyl acetate solution of α-dextrin.