Method for distinguishing silver ions and lead ions
By using the 'Na2SO3-NaBrO3-D-glucono-δ-lactone' pH clock system, a graph of the pH value changing over time after the addition of silver ions and lead ions is recorded, which solves the problem of expensive instrument detection in the existing technology and realizes the simple and rapid distinction between silver ions and lead ions.
Patent Information
- Application Number
- CN202510841690.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-23
- Publication Date
- 2025-09-09
AI Technical Summary
Existing metal ion detection methods require expensive and sophisticated instruments and are not suitable for on-site testing, making it difficult to quickly and easily distinguish between silver ions and lead ions.
The 'Na2SO3-NaBrO3-D-glucono-δ-lactone' pH clock system is used to record the pH value changes over time after the addition of different metal ions, and to distinguish silver ions from lead ions based on the difference in induction time.
At a temperature of 20-25 ℃, by comparing the changes in the induction time of the pH clock system, a simple and rapid distinction between silver ions and lead ions was achieved, with efficient distinction within the concentration range of 5.714×10-4mol/L-2.857×10-3mol/L.
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Figure CN120609964A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a differentiation method, specifically, to establishing a "Na2SO3-NaBrO3-D-glucono-δ-lactone" pH clock system. The induction time generated by the pH clock system is different according to the samples to be differentiated, thereby achieving differentiation of the samples to be differentiated. The present invention belongs to the field of analytical chemistry. Background Art
[0002] Metal ions are widely present in nature and play a huge role in human life. Silver ions are cations that carry a positive charge. In common compounds, they usually show a +1 valence and exist in the form of aqueous solutions. Silver ions have antibacterial and bactericidal effects and are widely used in water treatment, medical treatment, textiles and other fields. It can destroy the cell walls of bacteria, thereby inhibiting bacterial growth, but it should be noted that silver ion products must be used correctly to avoid side effects caused by excessive use. Lead is a heavy metal element that often exists in a +2 valence, forming relatively stable ions. It is widely present in nature and is used in many industrial processes, such as battery manufacturing and pigment production. In summary, different metal ions have different functions in nature and in the human body. In order to better use these metal ions, it is very necessary to distinguish these metal ions.
[0003] Currently, common methods for distinguishing metal ions include ultraviolet-visible spectrometry (UV), fluorescent probe technology (FP), atomic absorption spectroscopy (AAS), atomic emission spectroscopy (AES), and inductively coupled plasma mass spectrometry (ICP-MS). Although these analytical methods have their own advantages in metal ion detection, they all require expensive and sophisticated testing equipment, and the subsequent maintenance costs of the equipment are also high, making them unsuitable for on-site testing. Therefore, it is extremely necessary to find a detection and analysis method that has good detection results, is simple to operate, and is fast. Summary of the Invention
[0004] The present invention aims to provide a novel, convenient, and rapid method for distinguishing silver ions from lead ions, namely, a method for qualitatively detecting sample solutions to be distinguished using a "Na2SO3- NaBrO3-D-glucono-δ-lactone" pH clock system as a distinguishing solution. This method is based on the different sensitive responses of the pH clock system to different metal ions. Specifically, the "Na2SO3- NaBrO3-D-glucono-δ-lactone" pH clock reaction system is used as the distinguishing solution, and a graph of pH changes over time is recorded. When the pH clock reaction begins, equal volumes of sample solutions to be distinguished containing silver ions and lead ions of the same concentration are added to two sets of pH clock systems, respectively. The induction time generated by the pH clock system is different according to the samples to be distinguished, thereby achieving qualitative distinction of the samples to be distinguished.
[0005] The difference between the present qualitative differentiation method and the prior art is that the present invention uses the "Na2SO3-NaBrO3-D-glucono-δ-lactone" pH clock system as a differentiation solution, and makes the induction time generated by the pH clock system different according to the sample to be differentiated, thereby achieving differentiation of the samples to be differentiated: if after adding the solution to be differentiated, the induction time generated by the clock system is shortened to a small extent compared with the spectrum of pH value change over time without adding the solution to be differentiated, then the added sample to be differentiated is a sample containing silver ions; if after adding the solution to be differentiated, the induction time generated by the clock system is shortened to a large extent, then the added sample to be differentiated is a sample containing lead ions; When the sample solution to be differentiated is detected in the differentiation solution (pH clock system), the temperature of the pH clock system is controlled at any specific temperature within the range of 20-25°C.
[0006] The concentration range of silver ions and lead ions that can be distinguished in the distinguishing solution (pH clock system) is 5.714×10 -4 mol / L-2.857×10 -3 mol / L.
[0007] The concentration range for the solutions to be differentiated is the optimal concentration range determined experimentally. Within this concentration range, the effects of silver ions and lead ions on the differentiation solution are significantly different, making it easy to observe and analyze, and to achieve differentiation. Furthermore, the concentration ranges of the components in the differentiation solution (pH clock system) are shown in Table 1. The optimal solution for the differentiation solution (pH clock system) obtained through multiple experiments is shown in Table 2: Table 1: Concentration of components in the pH clock system <![CDATA[Na2SO3(mol / L)]]> <![CDATA[NaBrO3(mol / L)]]> D-Glucono-δ-lactone (mol / L) 0.0257-0.0471 0.0086-0.0171 0.0229-0.0343 Table 2: Optimal concentrations of components in the pH clock system <![CDATA[Na2SO3(mol / L)]]> <![CDATA[NaBrO3(mol / L)]]> D-Glucono-δ-lactone (mol / L) 0.0343 0.0143 0.0286 The specific experimental steps are as follows: 1. Prepare 35 mL of a differentiating solution (pH clock system) within the concentration range specified in Table 1. Keep its temperature constant at a specific value between 20 and 25°C. Insert the prepared working electrode (pH combination electrode, Leici, E-331) into the solution. Connect the other end of the working electrode to a computer via a potential / temperature / pH integrated tester (Jiaxing Disheng Electronic Technology Co., Ltd., ZHFX-595). Open the chemical signal acquisition and analysis program on the computer, set the acquisition time and sampling rate, and quickly click Start to monitor the pH of the solution. The computer records the pH change curve of the clock system over time, which is called the pH clock spectrum. When a substance is to be tested, the substance to be tested is added immediately upon the start of the pH clock system reaction. The pH clock spectrum of the pH change over time is recorded in the same manner.
[0008] The basic parameters of the pH clock spectrum include: Induction time: the time required from the start of the pH clock system reaction to pH stabilization. BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Figure 1 This is a graph showing the change in pH value of the differentiation solution (pH clock system) over time when no sample to be differentiated is added in Example 1.
[0010] Figure 2 In Example 1, 5.714×10 -4 mol / L silver ion solution, and then distinguish the pH value of the solution (pH clock system) over time.
[0011] Figure 3 In Example 1, 5.714×10 -4 mol / L lead ion solution, and then distinguish the pH value of the solution (pH clock system) over time.
[0012] Figure 4 This is a graph showing the change in pH value of the differentiation solution (pH clock system) over time when no sample to be differentiated is added in Example 2.
[0013] Figure 5 In Example 2, 1.714×10 -3 mol / L silver ion solution, and then distinguish the pH value of the solution (pH clock system) over time.
[0014] Figure 6 In Example 2, 1.714×10 -3 mol / L lead ion solution, and then distinguish the pH value of the solution (pH clock system) over time.
[0015] Figure 7 This is a graph showing the change in pH value of the differentiation solution (pH clock system) over time when no sample to be differentiated is added in Example 3.
[0016] Figure 8 In Example 3, 2.857×10 -3 mol / L silver ion solution, and then distinguish the pH value of the solution (pH clock system) over time.
[0017] Figure 9 In Example 3, 2.857×10 -3 mol / L lead ion solution, and then distinguish the pH value of the solution (pH clock system) over time. DETAILED DESCRIPTION Example 1
[0018] This example verifies the feasibility of the method for distinguishing silver ions from lead ions according to the present invention by the following steps: (1) Preparation of differentiation solution First, prepare 0.15 mol / L Na₂SO₃, 0.05 mol / L NaBrO₃, and 0.2 mol / L D-glucono-δ-lactone solutions in distilled water. To a 50-mL beaker, add 12 mL of distilled water, 8 mL of 0.15 mol / L Na₂SO₃ solution, 10 mL of 0.05 mol / L NaBrO₃ solution, and 5 mL of 0.2 mol / L D-glucono-δ-lactone solution, respectively. This ensures that the concentrations of the components in the "Na₂SO₃-NaBrO₃-D-glucono-δ-lactone" pH clock system are 0.0343 mol / L Na₂SO₃, 0.0143 mol / L NaBrO₃, and 0.0286 mol / L D-glucono-δ-lactone" in a total volume of 35 mL. The temperature was maintained at 23°C.
[0019] At the same time, distilled water was used as the solvent to prepare 0.05 mol / L concentrations of silver ions and lead ions to be distinguished.
[0020] (2) Obtaining pH clock map The graph of the pH value of the prepared differentiation solution (pH clock system) changing with time is recorded by a computer equipped with a chemical signal acquisition and analysis program (without adding the sample to be tested). Figure 1 As shown, the pH induction time was approximately 733 s, which served as a blank control. Two separate solutions were prepared with the same concentrations of each component as the above-mentioned differentiating solution. For one of the two solutions, 400 μL of a 0.05 mol / L silver ion solution sample solution was added to the 35 mL pH clock system using a pipette at the start of the reaction, so that its concentration in the differentiating solution was 5.714×10 -4 mol / L, the added silver ion solution makes the induction time of the system about 666 s, such as Figure 2 For the other group, 400 μL of 0.05 mol / L lead ion sample solution was added to the 35 mL pH clock system with a pipette at the beginning of the reaction, so that the concentration of lead ions in the distinguishing solution was 5.714×10 -4 mol / L, the added lead ions make the induction time of the system about 595 s, such as Figure 3 shown.
[0021] (3) Distinction According to the silver ions and lead ions in the samples to be distinguished, the induction time of the pH clock system is different, and the qualitative analysis of the samples to be distinguished is achieved. Figure 1 、 Figure 2 、 Figure 3 Compared to the pH-time curve without the sample, the addition of silver ion solution shortens the induction time of the clock system to a smaller extent, while the addition of lead ion solution shortens the induction time to a greater extent. These experiments demonstrate that silver and lead ions can be distinguished by comparing the induction times of the clock system.
[0022] Take two 0.05 mol / L solutions of the samples to be differentiated (one is a silver ion solution and the other is a lead ion solution, but the two have not been differentiated yet), mark one as sample 1 and the other as sample 2; prepare two sets of differentiation solutions with the same concentration of each component as above, add 400 μL of 0.05 mol / L sample 1 and sample 2 respectively, so that their concentrations in the differentiation solutions are 5.714×10 -4 mol / L.
[0023] The analysis and comparison show that the addition of sample 1 shortens the induction time of the pH clock system to a small extent (the degree of shortening of the induction time is similar to that of the Figure 2 Corresponding to Figure 3 The addition of sample 2 shortened the induction time of the pH clock system to a greater extent (the degree of shortening of the induction time is similar to that of Figure 3 Corresponding to Figure 2 Therefore, sample 1 is a silver ion solution and sample 2 is a lead ion solution, thereby achieving the distinction between silver ions and lead ions. Example 2
[0024] This example verifies the feasibility of the method for distinguishing silver ions from lead ions according to the present invention by the following steps: (1) Preparation of differentiation solution First, prepare 0.15 mol / L Na₂SO₃, 0.05 mol / L NaBrO₃, and 0.2 mol / L D-glucono-δ-lactone solutions in distilled water. To a 50-mL beaker, add 11.5 mL of distilled water, 8.2 mL of 0.15 mol / L Na₂SO₃ solution, 10.2 mL of 0.05 mol / L NaBrO₃ solution, and 5.1 mL of 0.2 mol / L D-glucono-δ-lactone solution, respectively. The concentrations of the components in the "Na₂SO₃-NaBrO₃-D-glucono-δ-lactone" pH clock system are 0.0351 mol / L Na₂SO₃, 0.0146 mol / L NaBrO₃, and 0.0291 mol / L D-glucono-δ-lactone, respectively. The total volume is 35 mL. The temperature is maintained at 23°C.
[0025] At the same time, distilled water was used as the solvent to prepare 0.15 mol / L concentrations of silver ions and lead ions to be distinguished.
[0026] (2) Obtaining pH clock map The graph of the pH value of the prepared differentiation solution (pH clock system) changing with time is recorded by a computer equipped with a chemical signal acquisition and analysis program (without adding the sample to be tested). Figure 4 As shown, the pH induction time was approximately 740 s for a blank control. Two separate solutions were prepared with the same concentrations of each component as the above-mentioned differentiating solution. For one of the solutions, 400 μL of a 0.15 mol / L silver ion solution sample solution was added to the 35 mL pH clock system using a pipette at the start of the reaction, resulting in a concentration of 1.714×10 -3 mol / L, the added silver ion solution makes the induction time of the system about 600 s, such as Figure 5 For the other group, 400 μL of 0.15 mol / L lead ion sample solution was added to the 35 mL pH clock system with a pipette at the beginning of the reaction, so that the concentration of lead ions in the distinguishing solution was 1.714×10 -3 mol / L, the added lead ions make the induction time of the system about 534 s, such as Figure 6 shown.
[0027] (3) Distinction According to the silver ions and lead ions in the samples to be distinguished, the induction time of the pH clock system is different, and the qualitative analysis of the samples to be distinguished is achieved. Figure 4 、 Figure 5 、 Figure 6Compared to the pH-time curve without the sample, the addition of silver ion solution shortens the induction time of the clock system to a smaller extent, while the addition of lead ion solution shortens the induction time to a greater extent. These experiments demonstrate that silver and lead ions can be distinguished by comparing the induction times of the clock system.
[0028] Take two 0.15 mol / L solutions of the samples to be differentiated (one is a silver ion solution and the other is a lead ion solution, but the two have not been differentiated yet), mark one as sample 1 and the other as sample 2; prepare two sets of differentiation solutions with the same concentration of each component as above, add 400 μL of 0.15 mol / L sample 1 and sample 2 respectively, so that their concentrations in the differentiation solutions are 1.714×10 -3 mol / L.
[0029] The analysis and comparison show that the addition of sample 1 shortens the induction time of the pH clock system to a small extent (the degree of shortening of the induction time is similar to that of the Figure 5 Corresponding to Figure 6 The addition of sample 2 shortened the induction time of the pH clock system to a greater extent (the degree of shortening of the induction time was similar to that of the Figure 6 Corresponding to Figure 5 Therefore, sample 1 is a silver ion solution and sample 2 is a lead ion solution, thereby achieving the distinction between silver ions and lead ions. Example 3
[0030] This example verifies the feasibility of the method for distinguishing silver ions from lead ions according to the present invention by the following steps: (1) Preparation of differentiation solution First, prepare 0.15 mol / L Na₂SO₃, 0.05 mol / L NaBrO₃, and 0.2 mol / L D-glucono-δ-lactone solutions in distilled water. To a 50-mL beaker, add 12.2 mL of distilled water, 7.8 mL of 0.15 mol / L Na₂SO₃ solution, 10.3 mL of 0.05 mol / L NaBrO₃ solution, and 4.7 mL of 0.2 mol / L D-glucono-δ-lactone solution, respectively. This ensures that the concentrations of the components in the "Na₂SO₃-NaBrO₃-D-glucono-δ-lactone" pH clock system are 0.0334 mol / L Na₂SO₃, 0.0147 mol / L NaBrO₃, and 0.0269 mol / L D-glucono-δ-lactone" in a total volume of 35 mL. The temperature was maintained at 23°C.
[0031] At the same time, distilled water was used as the solvent to prepare 0.25 mol / L concentrations of silver ions and lead ions to be distinguished.
[0032] (2) Obtaining pH clock map The graph of the pH value of the prepared differentiation solution (pH clock system) changing with time is recorded by a computer equipped with a chemical signal acquisition and analysis program (without adding the sample to be tested). Figure 7 As shown, the pH induction time was approximately 738 s for a blank control. Two separate solutions were prepared with the same concentrations of each component as the above-mentioned differentiating solution. For one of the solutions, 400 μL of a 0.25 mol / L silver ion solution sample solution was added to the 35 mL pH clock system using a pipette at the start of the reaction, so that its concentration in the differentiating solution was 2.857×10 -3 mol / L, the added silver ion solution makes the induction time of the system about 528 s. Figure 8 For the other group, 400 μL of 0.25 mol / L lead ion sample solution was added to the 35 mL pH clock system with a pipette at the beginning of the reaction, so that the concentration of lead ions in the distinguishing solution was 2.857×10 -3 mol / L, the added lead ions make the induction time of the system about 472 s, such as Figure 9 shown.
[0033] (3) Distinction According to the silver ions and lead ions in the samples to be distinguished, the induction time of the pH clock system is different, and the qualitative analysis of the samples to be distinguished is achieved. Figure 7 、 Figure 8 、 Figure 9 Compared to the pH-time curve without the sample, the addition of silver ion solution shortens the induction time of the clock system to a smaller extent, while the addition of lead ion solution shortens the induction time to a greater extent. These experiments demonstrate that silver and lead ions can be distinguished by comparing the induction times of the clock system.
[0034] Take two 0.25 mol / L solutions of the samples to be differentiated (one is a silver ion solution and the other is a lead ion solution, but the two have not been differentiated yet), mark one as sample 1 and the other as sample 2; prepare two sets of differentiation solutions with the same concentration of each component as above, add 400 μL of 0.25 mol / L sample 1 and sample 2 respectively, so that their concentrations in the differentiation solutions are 2.857×10 -3 mol / L.
[0035] The analysis and comparison show that the addition of sample 1 shortens the induction time of the pH clock system to a small extent (the degree of shortening of the induction time is similar to that of the Figure 8 Corresponding to Figure 9 The addition of sample 2 shortened the induction time of the pH clock system to a greater extent (the degree of shortening of the induction time was similar to that of the Figure 9 Corresponding to Figure 8 Therefore, sample 1 is a silver ion solution and sample 2 is a lead ion solution, thereby achieving the distinction between silver ions and lead ions.
Claims
1. A method for distinguishing silver ions from lead ions, characterized in that: Using distilled water as solvent, prepare sample solutions of silver ions and lead ions to be differentiated; The pH clock reaction system "Na2SO3- NaBrO3-D-glucono-δ-lactone" was used as the distinguishing solution, and a graph showing the pH value of the clock system changing with time was recorded. The temperature of the pH clock system is controlled at any specific temperature within the range of 20-25°C. When the pH clock reaction begins, equal volumes of sample solutions containing silver ions and lead ions of the same concentration to be differentiated are added to the two pH clock systems, respectively. The induction time generated by the pH clock system is different according to the samples to be differentiated, thereby achieving differentiation of the samples to be differentiated: if the induction time generated by the clock system is shortened to a lesser extent after the solution to be differentiated is added, compared with the pH value change over time without the solution to be differentiated, then the added sample to be differentiated is a sample containing silver ions. If the induction time of the clock system is greatly shortened after the solution to be differentiated is added, then the sample to be differentiated is a lead ion-containing sample; The molar concentration range of each component in the solution is: Na2SO30.0257-0.0471 mol / L, NaBrO30.0086-0.0171 mol / L, D-glucono-δ-lactone0.0229-0.0343 mol / L.
2. The method according to claim 1, wherein: The molar concentrations of the components in the differentiated solution were Na2SO3 0.0343 mol / L, NaBrO3 0.0143 mol / L, and D-glucono-δ-lactone 0.0286 mol / L.
3. The method according to claim 1, wherein: The concentration range of the sample to be differentiated in the differentiation solution is 5.714×10 -4 mol / L-2.857×10 -3 mol / L.
4. The method according to claim 1, wherein: The clock system temperature was controlled at 23 °C.