A method for preparing a gamma-ray irradiation shielding gel

Abstract

This invention discloses a method for preparing a gamma-ray resistant gel, comprising the following steps: First, under room temperature conditions, all chemical components are sequentially added to a container and stirred until all components are completely dissolved to obtain a homogeneous liquid gel. The chemical components consist of a solvent, a reference electrolyte, a buffer system, and a polymer gelling agent. After irradiating the prepared gel with 55 kGy of gamma rays, the viscosity increased from 129.48 cP before irradiation to 190.4 cP, while maintaining a viscous liquid state. The pH value changed from 6.912 before irradiation to 6.992, a change of less than 0.1 units. This demonstrates that the gel remains physically and chemically stable after gamma irradiation, without degradation, ensuring that the reference electrode can still be used normally after irradiation sterilization, meeting the requirements of disposable pH sensors in hygienic applications.

Description

Technical Field

[0001] This invention relates to the field of electrochemical sensor technology, specifically to a method for preparing a γ-radiation-resistant gel. Background Technology

[0002] The pH electrode measures pH using electrochemical potentialism. The pH value is calculated using the Nernst equation based on the potential difference between the indicating electrode and the reference electrode. The reference electrode provides a constant reference potential and should be undisturbed. If a liquid reference electrolyte is used, the reference electrode is highly susceptible to sample contamination. In industrial applications, exposure to high temperatures and pressures, and even under certain positive pressure shocks, can cause response fluctuations. These fluctuations can lead to significant numerical measurement errors.

[0003] Currently, the main solution to this problem is to use a high-viscosity reference electrolyte to replace the aqueous, low-viscosity reference solution. The high viscosity of the solution can reduce the fluctuations in ion diffusion at the liquid junction caused by pressure, thereby reducing interference with the reference electrode. Although several reference gel formulations based on cellulose and agar are available on the market, and these gels are widely used in laboratory pH sensors, they cannot remain stable under gamma irradiation. After gamma irradiation experiments, it was observed that radiation alters the physicochemical properties of these gels, leading to a significant decrease in gel viscosity and changes in pH.

[0004] However, because gamma irradiation is suitable for single-use fermentation systems, this sterilization method can significantly shorten tank changeover time and reduce contamination risks. Therefore, in some fermentation applications, it is the only feasible terminal sterilization method, such as for single-use pharmaceutical pH sensors, where gamma irradiation is the standard sterilization process. This also means that this type of gel is unsuitable for single-use pharmaceutical pH sensors.

[0005] To address this problem, a method for preparing a gamma-radiation-resistant gel is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing a γ-radiation resistant gel, which solves the problem that the reference gel currently used inside laboratory pH sensors cannot remain stable under γ-radiation and is therefore unsuitable for disposable pharmaceutical-grade hygienic pH sensor products that need to withstand a certain pressure.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a gamma-ray protection gel, comprising the following steps:

[0008] Step 1: Raw material dissolution: First, at room temperature, add all chemical components to the container in sequence and stir until all components are completely dissolved to obtain a homogeneous liquid gel; the chemical components consist of solvent, reference electrolyte, buffer system, and polymer gelling agent;

[0009] Step 2: Sample Measurement: The viscosity of the obtained liquid gel sample was measured at 25°C using a viscometer, and the pH value was measured to be approximately 129.48 cP. The pH value was measured to be 6.912 using a pH meter.

[0010] Step 3: Irradiation Re-measurement: Finally, the liquid gel sample was irradiated with 55 kGy of gamma rays, and its viscosity and pH value were measured after irradiation. After gamma irradiation, the viscosity of the gel sample did not decrease, but increased to 190.4 cP, and still maintained a viscous liquid state; the pH value changed to 6.992, a change of less than 0.1 pH units; thus proving that the gel is physically and chemically stable after gamma irradiation and does not undergo degradation.

[0011] Preferably, in step 1, the reference electrolyte is one of potassium chloride, lithium chloride, cesium chloride, or potassium nitrate at 1.5M; and the dual liquid junction structure provides a stable liquid junction potential that is independent of the sample.

[0012] Preferably, in step 1, the buffer system is 0.1M potassium dihydrogen phosphate and 0.03M potassium hydroxide.

[0013] Preferably, in step 1, the polymer gelling agent is a polyethylene glycol methacrylate (CAS No.: 25736-86-1) gelling agent with a molecular weight of less than 15.00 and a concentration of 60 wt.%, and fumed silica is also added.

[0014] Preferably, in step 1, the solvent is water (the balance).

[0015] Preferably, in step 1, all four chemical components are biocompatible.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] The gel of this invention, after being irradiated with gamma rays at a dose of up to 55 kGy, showed an increase in viscosity from 129.48 cP to 190.4 cP while maintaining a viscous liquid state; the pH value changed from 6.912 to 6.992, a change of less than 0.1 units. This demonstrates that the gel remains physically and chemically stable after gamma irradiation, without degradation, ensuring that the reference electrode can still be used normally after irradiation sterilization, meeting the requirements of disposable pH sensors in hygienic applications. Attached Figure Description

[0018] Figure 1 This is a graph showing the changes in data of the gel of this invention after γ-irradiation;

[0019] Figure 2 This is a graph showing the changes in data after ordinary gels are irradiated with gamma. Detailed Implementation

[0020] The present invention will now be described in more detail by way of examples. These examples are merely illustrative and do not limit the scope of the present invention in any way.

[0021] This invention provides a technical solution: a method for preparing a gamma-ray protection gel, comprising the following steps:

[0022] Step 1: Raw material dissolution: First, at room temperature, add all chemical components to the container in sequence and stir until all components are completely dissolved to obtain a homogeneous liquid gel; the chemical components consist of solvent, reference electrolyte, buffer system, and polymer gelling agent;

[0023] Step 2: Sample Measurement: The viscosity of the obtained liquid gel sample was measured at 25°C using a viscometer, and the pH value was measured to be approximately 129.48 cP. The pH value was measured to be 6.912 using a pH meter.

[0024] Step 3: Irradiation Re-measurement: Finally, the liquid gel sample was irradiated with 55 kGy of gamma rays, and its viscosity and pH value were measured after irradiation. After gamma irradiation, the viscosity of the gel sample did not decrease, but increased to 190.4 cP, and still maintained a viscous liquid state; the pH value changed to 6.992, a change of less than 0.1 pH units; thus proving that the gel is physically and chemically stable after gamma irradiation and does not undergo degradation.

[0025] Example 1:

[0026] First, at room temperature, all chemical components were sequentially added to a container and stirred until all components were completely dissolved, resulting in a homogeneous liquid gel. The chemical components consisted of a solvent, a reference electrolyte, a buffer system, and a polymer gelling agent. The resulting liquid gel sample was then tested at 25°C; the viscosity was measured to be approximately 129.48 cP, and the pH was measured to be 6.912. Finally, the liquid gel sample was irradiated with 55 kGy of gamma rays, and its viscosity and pH were measured after irradiation. After gamma irradiation, the viscosity of the gel sample did not decrease but increased to 190.4 cP, while still maintaining a viscous liquid state. The pH value changed to 6.992, a change of less than 0.1 pH units. This demonstrates that the gel's physical and chemical properties remained stable after gamma irradiation and did not degrade.

[0027] Example 2:

[0028] In Example 1, the following steps are added:

[0029] In step 1, the reference electrolyte is one of potassium chloride, lithium chloride, cesium chloride, or potassium nitrate at 1.5 M. A dual liquid junction structure is employed to provide a stable liquid junction potential independent of the sample. The buffer system consists of 0.1 M potassium dihydrogen phosphate and 0.03 M potassium hydroxide to adjust the pH of the gel. The polymer gelling agent is polyethylene glycol methacrylate (CAS No.: 25736-86-1) with a molecular weight less than 15.00 and a concentration of 60 wt.%. Additionally, fumed silica (silica) is added to control the gel viscosity. The gel viscosity can be adjusted by changing the concentration and molecular weight of the polymer gelling agent. The fumed silica is unaffected by pH interference from the sample and remains stable under γ-irradiation, ensuring that the physical properties of the gel do not change significantly.

[0030] First, at room temperature, all chemical components were sequentially added to a container and stirred until completely dissolved, resulting in a homogeneous liquid gel. The chemical components consisted of a solvent, a reference electrolyte, a buffer system, and a polymer gelling agent. The resulting liquid gel sample was then tested at 25°C; the viscosity was measured to be approximately 129.48 cP, and the pH was measured to be 6.912. Finally, the liquid gel sample was irradiated with 55 kGy of gamma rays, and its viscosity and pH were measured after irradiation. After gamma irradiation, the viscosity of the gel sample did not decrease; instead, it increased to 190.4 cP. The gel remained viscous liquid, with the pH value changing to 6.992, a change of less than 0.1 pH units. This demonstrated that the gel's physical and chemical properties remained stable after γ-irradiation and did not degrade. The reference electrolyte was one of 1.5 M potassium chloride, lithium chloride, cesium chloride, or potassium nitrate. The dual liquid junction structure provided a stable liquid junction potential independent of the sample. The buffer system consisted of 0.1 M potassium dihydrogen phosphate and 0.03 M potassium hydroxide to adjust the gel's pH. The polymer gelling agent was polyethylene glycol methacrylate (CAS No.: 25736-86-1) with a molecular weight less than 15.00 and a concentration of 60 wt.%. In addition, fumed silica was added to control the gel's viscosity. The gel's viscosity could be adjusted by changing the concentration and molecular weight of the polymer gelling agent. The fumed silica was unaffected by the pH of the sample and remained stable under γ-irradiation, ensuring that the gel's physical properties did not change significantly.

[0031] Example 3:

[0032] In Example 2, the following additional steps are added:

[0033] In step 1, the solvent is water (balance); all four chemical components are biocompatible, making them suitable for hygienic applications, but also suitable for other uses beyond hygienic applications.

[0034] First, at room temperature, all chemical components were sequentially added to a container and stirred until completely dissolved, resulting in a homogeneous liquid gel. The chemical components consisted of a solvent, a reference electrolyte, a buffer system, and a polymer gelling agent. The resulting liquid gel sample was then tested at 25°C; the viscosity was measured to be approximately 129.48 cP, and the pH was measured to be 6.912. Finally, the liquid gel sample was irradiated with 55 kGy of gamma rays, and its viscosity and pH were measured after irradiation. After gamma irradiation, the viscosity of the gel sample did not decrease; instead, it increased to 190.4 cP. The gel remained viscous liquid, with the pH value changing to 6.992, a change of less than 0.1 pH units. This demonstrates that the gel remained physically and chemically stable after γ-irradiation and did not degrade. The reference electrolyte was one of 1.5 M potassium chloride, lithium chloride, cesium chloride, or potassium nitrate. The dual liquid junction structure provided a stable and sample-independent liquid junction potential. The buffer system consisted of 0.1 M potassium dihydrogen phosphate and 0.03 M potassium hydroxide to adjust the pH of the gel. The polymer gelling agent had a molecular weight less than 15.00 and a concentration of 60%. The gel contains wt.% polyethylene glycol methacrylate (CAS No.: 25736-86-1) gelling agent, along with fumed silica (silica) to control the viscosity of the gel. The viscosity of the gel can be controlled by changing the concentration and molecular weight of the polymer gelling agent. The fumed silica is unaffected by pH fluctuations from the sample and remains stable under gamma irradiation, ensuring that the physical properties of the gel do not change significantly. The solvent is water (balance). All four chemical components are biocompatible, making them suitable for hygienic applications, but also suitable for other uses beyond hygienic applications.

[0035] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a gamma-ray irradiation-resistant gel, characterized in that: Includes the following steps: Step 1: Raw material dissolution: First, at room temperature, add all chemical components to the container in sequence and stir until all components are completely dissolved to obtain a homogeneous liquid gel; the chemical components consist of solvent, reference electrolyte, buffer system, and polymer gelling agent; Step 2: Sample Measurement: The viscosity of the obtained liquid gel sample was measured at 25°C using a viscometer, and the pH value was measured to be approximately 129.48 cP. The pH value was measured to be 6.912 using a pH meter. Step 3: Irradiation Re-measurement: Finally, the liquid gel sample was irradiated with 55 kGy of gamma rays, and its viscosity and pH value were measured after irradiation. After gamma irradiation, the viscosity of the gel sample did not decrease, but increased to 190.4 cP, and still maintained a viscous liquid state; the pH value changed to 6.992, a change of less than 0.1 pH units; thus proving that the gel is physically and chemically stable after gamma irradiation and does not undergo degradation.

2. The method for preparing a gamma-ray irradiation shielding gel according to claim 1, characterized in that: In step 1, the reference electrolyte is one of potassium chloride, lithium chloride, cesium chloride, or potassium nitrate at 1.5M; at the same time, the dual liquid junction structure provides a stable liquid junction potential that is independent of the sample.

3. The method for preparing a gamma-ray protection gel according to claim 1, characterized in that: In step 1, the buffer system consists of 0.1 M potassium dihydrogen phosphate and 0.03 M potassium hydroxide.

4. The method for preparing a gamma-ray protection gel according to claim 1, characterized in that: In step 1, the polymer gelling agent is polyethylene glycol methacrylate (CAS No.: 25736-86-1) gelling agent with a molecular weight of less than 15.00 and a concentration of 60 wt.%, and fumed silica is also added.

5. The method for preparing a gamma-ray protection gel according to claim 1, characterized in that: In step 1, the solvent is water (the remainder).

6. The method for preparing a gamma-ray protection gel according to claim 1, characterized in that: In step 1, all four chemical components are biocompatible.

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