Application of Keratin in the Shell of Snails to Radiocarbon 14 Dating

Abstract

The present invention discloses the application of the keratin of the shell of snails in the radiocarbon 14 dating, and relates to the technical field of radiocarbon dating. Here, the method for extracting the keratin of the shell of snails includes the steps of collecting a sample of the shell of snails, performing crushing and washing treatments to obtain the washed shell of snails; sequentially immersing the washed shell of snails in a hydrogen peroxide solution and a first phosphoric acid solution, then washing with decarbonized water and freeze-drying to obtain a pretreated sample; preparing a second phosphoric acid solution with decarbonized water and orthophosphoric acid; putting the pretreated sample into the second phosphoric acid solution for decomposition to obtain a water-soluble solution containing the keratin of the shell of snails, filtering the residue, and then separating and purifying to obtain a keratin sample of the shell of snails. By adopting a method for extracting the keratin of the shell of snails with high efficiency and low pollution, the present invention is applicable to high-precision radiocarbon 14 dating research and has important scientific and practical application values.

Description

Technical Field

[0001] The present invention relates to the technical field of radiocarbon dating, and particularly to the application of keratin in the shell of snails in the dating of radiocarbon 14.

Background Art

[0002] Radiocarbon 14 ( 14 C) dating method is a technique for measuring the age of organic substances by utilizing the radioactive decay of carbon-14.

[0003] Traditional 14 The reliability of C dating materials limits the application of the high-precision accelerator 14 C dating method in paleoclimate research. The shells of snails in the loess of Xinjiang, China are ideal 14 C dating materials, but there is a lack of efficient and reliable extraction and preparation methods, which limits their wide application.

Summary of the Invention

Means for Solving the Problems

[0004] In order to solve the above problems of the prior art, the present invention aims to provide the application of keratin in the shell of snails in the dating of radiocarbon 14.

[0005] To achieve the above object, the main technical solutions adopted by the present invention include the following: The application of keratin in the shell of snails in the dating of radiocarbon 14, wherein The method for extracting the keratin from the shell of snails is as follows: Collecting a sample of the shell of snails, performing crushing and washing treatments to obtain the washed shell of snails; Sequentially immersing the washed shell of snails in a hydrogen peroxide solution and a first phosphoric acid solution, then washing with demineralized water and freeze-drying to obtain a pretreated sample; Preparing a second phosphoric acid solution with demineralized water and orthophosphoric acid; Put the pretreatment sample into the second phosphoric acid solution for decomposition to obtain a water-soluble solution containing the keratin of the snail shell. After filtering the residue, separate and purify it to obtain a keratin sample of the snail shell.

[0006] Preferably, the mass concentration of the hydrogen peroxide solution is 3% - 7%.

[0007] Preferably, the mass concentration of the first phosphoric acid solution is 1% - 3%.

[0008] Preferably, the method for preparing the decarbonized water is as follows: Mix ultrapure water with a supersaturated oxidation solution of potassium peroxydisulfate, perform a water bath reaction to obtain a reacted solution. Recrystallize the reacted solution to obtain decarbonized water.

[0009] Preferably, the method for recrystallization is as follows: Heat the obtained decarbonized water to 35 - 45°C, and gradually add potassium peroxydisulfate until saturation. After cooling to room temperature, cool it at 3 - 5°C to promote the crystallization of potassium peroxydisulfate to obtain crystals. Subsequently, filter, wash the crystals with cold decarbonized water, repeat the recrystallization process multiple times to achieve the purification effect, and lyophilize potassium peroxydisulfate.

[0010] Preferably, the supersaturated oxidation solution of potassium peroxydisulfate contains potassium peroxydisulfate, ultrapure water, and a third phosphoric acid solution. The mass concentration of the third phosphoric acid solution is 80% - 90%. In the supersaturated oxidation solution of potassium peroxydisulfate, the volume ratio of the third phosphoric acid solution to ultrapure water is (1.5 - 2.5):1.

[0011] Preferably, the temperature of the water bath reaction is 100°C.

[0012] Preferably, the mass concentration of the second phosphoric acid solution is 40% - 60%.

[0013] Preferably, the condition for decomposition is a water bath condition of 65 to 75 °C.

[0014] Preferably, the method for measuring the age of radiocarbon 14 using the keratin of the shell of a snail is as follows: Place the purified keratin sample of the snail shell in a reactor, add a supersaturated oxidation solution of potassium peroxydisulfate, put it into a vacuum system, perform vacuum pumping, then carry out a water bath reaction, freeze-collect CO2 gas, record the gas pressure, and calculate the carbon content of the keratin of the snail shell.

Advantages of the Invention

[0015] The present invention provides the application of the keratin of the snail shell in the measurement of the age of radiocarbon 14. By adopting a method for extracting the keratin of the snail shell with high efficiency and low pollution, it is applicable to high-precision radiocarbon 14 age measurement research and has important scientific and practical application values. According to the experimental results, the F 14 C value of the keratin of the snail shell extracted by this method is close to the F 14 C value of local plants or the atmosphere, and the difference in the F 14 C values of the keratin of snail shells with different attributes and sizes is small. Therefore, the keratin of the snail shell extracted by this method can be used as a reliable material for radiocarbon 14 age measurement.

Brief Description of the Drawings

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Figure 1

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Embodiments for Carrying Out the Invention

[0017] Hereinafter, in relation to the embodiments of the present invention, the technical aspects in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the examples in the present invention, all other examples obtained by those skilled in the art without creative labor belong to the protection scope of the present invention.

[0018] In one embodiment of the present invention, an application of the keratin of the snail shell in the radiocarbon-14 dating is provided, wherein the method for extracting the keratin of the snail shell is as follows. Step S1 of collecting a sample of the snail shell, performing crushing and washing treatments, and obtaining the washed snail shell. Step S2 of sequentially immersing the washed snail shell in a hydrogen peroxide solution with a mass concentration of 3% - 7% and a first phosphoric acid solution with a mass concentration of 1% - 3%, then washing with deionized water and freeze-drying to obtain a pretreated sample. Step S3 of preparing a second phosphoric acid solution with a mass concentration of 40% - 60% using deionized water and orthophosphoric acid. Step of putting the pretreated sample into the second phosphoric acid solution and performing decomposition under a water bath condition of 65 - 75°C to obtain a water-soluble solution containing the keratin of the snail shell, filtering the residue, and then separating and purifying to obtain a keratin sample of the snail shell.

[0019] In the examples of the present invention, by using phosphoric acid as a raw material, the contamination of the keratin of the snail shell can be reduced. In contrast, when hydrochloric acid is used as a raw material, it is disadvantageous for subsequent oxidation using potassium peroxydisulfate. Potassium peroxydisulfate oxidizes chloride ions to chlorine gas, which affects health. Also, the examples of the present invention use deionized water as the solvent of the second phosphoric acid solution, which can avoid the interference of trace carbon contamination in water with the keratin of the snail shell.

[0020] Here, the method for preparing deionized water is as follows. Mix the ultrapure water with a supersaturated oxidation solution of potassium peroxydisulfate, conduct a water bath reaction at 100 °C to obtain a reacted solution. Here, the supersaturated oxidation solution of potassium peroxydisulfate contains potassium peroxydisulfate, ultrapure water, and a third phosphoric acid solution. The mass concentration of the third phosphoric acid solution is 80 - 90%, and in the supersaturated oxidation solution of potassium peroxydisulfate, the volume ratio of the third phosphoric acid solution to ultrapure water is (1.5 - 2.5):1 (step S21). It includes step S22 of subjecting the reacted solution to recrystallization treatment to obtain decarbonized water. Specifically, the method of recrystallization treatment is as follows: Heat the obtained decarbonized water to 35 - 45 °C, and gradually add potassium peroxydisulfate until saturation. After cooling to room temperature, cool it at 3 - 5 °C to promote the crystallization of potassium peroxydisulfate and obtain crystals. Subsequently, filter, wash the crystals with cold decarbonized water, repeat the recrystallization process multiple times to achieve a purification effect, and include freeze-drying potassium peroxydisulfate.

[0021] Note that both the first phosphoric acid solution and the third phosphoric acid solution can be prepared using the above decarbonized water and orthophosphoric acid.

[0022] In a preferred embodiment of the present invention, the method for measuring the age of radiocarbon 14 using the keratin of the shell of the snail Helix pomatia includes the following steps: Place the purified keratin sample of the shell of the snail Helix pomatia in a reactor, add a supersaturated oxidation solution of potassium peroxydisulfate, put it into a vacuum system, evacuate, conduct a water bath reaction, freeze-collect CO2 gas, record the gas pressure, and calculate the carbon content of the keratin of the shell of the snail Helix pomatia.

[0023] The following examples are examples where the technical means of the present invention have been put into practice, but are not limited thereto. All related reagents and experimental devices are commercially available products.

[0024] (Example 1) This example provides a method for extracting keratin from the shell of a snail, specifically including the following steps: (1) Producing decarbonized water: Put 100 mL of ultrapure water into a 250 mL conical flask, add 20 mL of a supersaturated oxidation solution of potassium peroxydisulfate, react in a water bath at 100 °C for 6 hours, then cool to room temperature and store sealed. Here, the supersaturated oxidation solution of potassium peroxydisulfate is obtained by mixing 100 mL of ultrapure water, 4 g of potassium peroxydisulfate, and 200 mL of a phosphoric acid solution with a mass concentration of 80 - 90%. Recrystallization of potassium peroxydisulfate: Heat the decarbonized water prepared above to 40 °C, gradually add potassium peroxydisulfate until saturated, cool to room temperature, then cool to 4 °C to promote the crystallization of potassium peroxydisulfate, obtain crystals, then filter, wash the crystals with cold decarbonized water, repeat the recrystallization process multiple times to achieve a purification effect, freeze-dry the potassium peroxydisulfate sample, and put it into a storage container.

[0025] (2) Extracting keratin from the shell of a snail S1: Gently crush the snail shell sample, put it into an ultrasonic cleaner, wash it with deionized water to remove the fine particles and some soluble organic substances adhering to the inner surface, and gently remove the loose particles or contaminants on the inner and outer surfaces of the shell body using a soft brush or a fine needle under a microscope to obtain the washed snail shell.

[0026] S2: Immerse the washed snail shell in a hydrogen peroxide solution with a mass concentration of 5% to remove the adhering organic matter, then immerse it in a first phosphoric acid solution with a mass concentration of 2% for a short time to remove the contamination of inorganic carbonate as much as possible, slightly dissociate some organic matter, then wash with decarbonized water and freeze-dry to obtain a pretreated sample.

[0027] S3: Prepare a second phosphoric acid solution with a mass concentration of 50% using the above carbon-free water and orthophosphoric acid to prepare for decomposing the carbonate of the snail shell.

[0028] S4. Place the above pretreated sample into a second phosphoric acid solution, decompose it under the condition of a water bath at 70°C. After 24 hours, when the pH value of the solution is 2 - 3, the decomposition of the carbonate in the snail shell is completed, and the keratin in the snail shell is hydrolyzed into a water-soluble solution to obtain a water-soluble solution containing the keratin in the snail shell. Filter the residue, and then separate and purify it to obtain a keratin sample of the snail shell.

[0029] Among them, for the separation and purification method, based on the molecular size of the contaminants, it was selected to perform separation and purification using nanofiltration, ultrafiltration, or high-performance liquid chromatography (HPLC). The method for evaluating the purification effect can be to analyze the purification effect using techniques such as liquid chromatography / mass spectrometry. The method for identifying and analyzing the contaminant molecules can be to identify and quantitatively analyze the water-soluble organic substances using a liquid chromatography-mass spectrometer to determine the contaminating components of keratin and their contamination levels. The quality control method for the sample can adopt methods such as removing the organic substances attached to the glass container at 550°C and classifying and storing them, and perform quality control in the whole experimental operation by means such as blank tests to ensure the accuracy and reliability of the experimental results.

[0030] (Example 2) This example provides a method for extracting keratin from a snail shell, specifically including the following steps: (1) Produce deionized water. Put 100 mL of ultrapure water into a 250 mL conical flask, add 20 mL of a supersaturated oxidation solution of potassium peroxydisulfate, react in a 100°C water bath for 6 hours, then cool it to room temperature and store it sealed. Here, the supersaturated oxidation solution of potassium peroxydisulfate is obtained by mixing 100 mL of ultrapure water, 3.3 g of potassium peroxydisulfate, and 150 mL of a phosphoric acid solution with a mass concentration of 80%. Recrystallization of potassium peroxydisulfate: Heat the decarbonized water prepared above to 35 °C, gradually add potassium peroxydisulfate until saturation, cool to room temperature, then cool to 3 °C to promote crystallization of potassium peroxydisulfate, obtain crystals, then filter, wash the crystals with cold decarbonized water, repeat the recrystallization process multiple times to achieve the purification effect, freeze-dry the potassium peroxydisulfate sample, and put it into a storage container.

[0031] (2) Extracting the keratin of the snail shell S1: Gently crush the snail shell sample, put it into an ultrasonic cleaner, wash it with deionized water to remove the fine particles and some soluble organic substances adhering to the inner surface, and gently remove the loose particles or contaminants on the inner and outer surfaces of the shell using a soft brush or a fine needle under a microscope to obtain the washed snail shell.

[0032] S2: Immerse the washed snail shell in a hydrogen peroxide solution with a mass concentration of 3%, remove the attached organic matter, then immerse it in a first phosphoric acid solution with a mass concentration of 1% for a short time to remove the contamination of inorganic carbonates as much as possible, slightly dissociate some organic matter, then wash it with decarbonized water and freeze-dry to obtain a pretreated sample.

[0033] S3: Prepare a second phosphoric acid solution with a mass concentration of 40% using the above carbon-free water and orthophosphoric acid for preparing to decompose the carbonate of the snail shell.

[0034] S4: Put the above pretreated sample into the second phosphoric acid solution and decompose it under the water bath condition of 65 °C. After 24 hours, when the pH value of the solution is 2 - 3, the decomposition of the carbonate of the snail shell is completed, hydrolyze the keratin of the snail shell into a water-soluble solution, obtain a water-soluble solution containing the keratin of the snail shell, filter the residue, and then separate and purify it to obtain a keratin sample of the snail shell.

[0035] (Example 3) This example provides a method for extracting the keratin of the snail shell, specifically including the following steps: (1) Producing decarbonized water. Put 100 mL of ultrapure water into a 250 mL conical flask, add 20 mL of a supersaturated oxidation solution of potassium peroxydisulfate, react in a 100 °C water bath for 6 hours, then cool to room temperature and store in a sealed manner. Here, the supersaturated oxidation solution of potassium peroxydisulfate is obtained by mixing 100 mL of ultrapure water, 4.7 g of potassium peroxydisulfate and 250 mL of a 90% mass concentration phosphoric acid solution. Recrystallization of potassium peroxydisulfate. Heat the decarbonized water prepared above to 45 °C, gradually add potassium peroxydisulfate until saturation, cool to room temperature, then cool to 5 °C to promote the crystallization of potassium peroxydisulfate, obtain crystals, then filter, wash the crystals with cold decarbonized water, repeat the recrystallization process multiple times to achieve the purification effect, freeze-dry the potassium peroxydisulfate sample and put it into a storage container.

[0036] (2) Extracting the keratin of the shell of the snail S1. Gently crush the snail shell sample, put it into an ultrasonic cleaner, wash it with deionized water to remove the fine particles and some soluble organic substances adhering to the inner surface, and gently remove the loose particles or contaminants on the inner and outer surfaces of the shell body using a soft brush or a fine needle under a microscope to obtain the washed snail shell.

[0037] S2. Immerse the washed snail shell in a 7% mass concentration hydrogen peroxide solution to remove the adhering organic matter, then immerse it in a 3% mass concentration phosphoric acid solution for a short time to remove the inorganic carbonate contamination as much as possible, slightly dissociate some organic matter, then wash with decarbonized water and freeze-dry to obtain a pretreated sample.

[0038] S3. Prepare a 60% mass concentration phosphoric acid solution using the above carbon-free water and orthophosphoric acid to prepare for decomposing the carbonate of the snail shell.

[0039] S4. Put the above pretreated sample into a second phosphoric acid solution, decompose it under the condition of a water bath at 75 °C. After 24 hours, when the pH value of the solution is 2 - 3, the decomposition of the carbonate in the snail shell is completed, and the keratin in the snail shell is hydrolyzed into a water-soluble solution, obtaining a water-soluble solution containing the keratin of the snail shell. Filter the residue, and then separate and purify it to obtain a keratin sample of the snail shell.

[0040] (Example 4) This example provides a method for extracting keratin from snail shells, specifically including the following steps: (1) Produce decarbonized water. Put 100 mL of ultrapure water into a 250 mL conical flask, add 15 mL of a supersaturated oxidation solution of potassium peroxydisulfate, react in a water bath at 100 °C for 6 hours, then cool to room temperature and store it sealed. Here, the supersaturated oxidation solution of potassium peroxydisulfate is obtained by mixing 100 mL of ultrapure water, 4 g of potassium peroxydisulfate and 200 mL of a phosphoric acid solution with a mass concentration of 82%. Recrystallization of potassium peroxydisulfate. Heat the decarbonized water prepared above to 38 °C, gradually add potassium peroxydisulfate until saturation, cool to room temperature, then cool at 4 °C to promote the crystallization of potassium peroxydisulfate to obtain crystals. Subsequently, filter and wash the crystals with cold decarbonized water, repeat the recrystallization process multiple times to achieve the purification effect, freeze-dry the potassium peroxydisulfate sample and put it into a storage container.

[0041] (2) Extract the keratin of the snail shell S1. Gently crush the snail shell sample, put it into an ultrasonic cleaner, wash it with deionized water to remove the fine particles and some soluble organic substances attached to the inner surface, and gently remove the loose particles or contaminants on the inner and outer surfaces of the shell body with a soft brush or a fine needle under a microscope to obtain the washed snail shell.

[0042] S2. After soaking the shells of the snails after washing in a hydrogen peroxide solution with a mass concentration of 4% to remove the attached organic matter, soak them briefly in a first phosphoric acid solution with a mass concentration of 1.5% to remove as much inorganic carbonate contamination as possible, slightly dissociate some of the organic matter, then wash with deionized water and freeze-dry to obtain a pretreated sample.

[0043] S3. Prepare a second phosphoric acid solution with a mass concentration of 45% using the above deionized water and orthophosphoric acid, and prepare it for decomposing the carbonate of the snail shell.

[0044] S4. Put the above pretreated sample into the second phosphoric acid solution and decompose it under the water bath condition of 68 °C. After 24 hours, when the pH value of the solution is 2-3, the decomposition of the carbonate of the snail shell is completed, and the keratin of the snail shell is hydrolyzed into a water-soluble solution to obtain a water-soluble solution containing the keratin of the snail shell. Filter the residue, and then separate and purify it to obtain a keratin sample of the snail shell.

[0045] (Example 5) This example provides a method for extracting keratin from the shells of snails, specifically including the following steps: (1) Produce deionized water. Put 100 mL of ultrapure water into a 250 mL conical flask, add 25 mL of a supersaturated oxidation solution of potassium peroxydisulfate, react in a 100 °C water bath for 6 hours, then cool at room temperature and store it sealed. Here, the supersaturated oxidation solution of potassium peroxydisulfate is obtained by mixing 100 mL of ultrapure water, 4 g of potassium peroxydisulfate and 200 mL of a third phosphoric acid solution with a mass concentration of 88%. Recrystallization of potassium peroxydisulfate. Heat the deionized water prepared above to 42 °C, gradually add potassium peroxydisulfate until saturation, cool to room temperature, then cool at 4 °C to promote the crystallization of potassium peroxydisulfate to obtain crystals. Subsequently, filter and wash the crystals with cold deionized water, repeat the recrystallization process multiple times to achieve the purification effect, freeze-dry the potassium peroxydisulfate sample and put it into a storage container.

[0046] (2) Extract the keratin of the snail shell S1. Gently crush the shell sample of the snail, place it in an ultrasonic cleaner, wash it with deionized water to remove the fine particles and some soluble organic substances adhering to the inner surface, and gently remove the loose particles or contaminants on the inner and outer surfaces of the shell using a soft brush or a fine needle under a microscope to obtain the washed snail shell.

[0047] S2. Immerse the washed snail shell in a hydrogen peroxide solution with a mass concentration of 6% to remove the adhering organic matter, then immerse it in a first phosphoric acid solution with a mass concentration of 2.5% for a short time to remove the contamination of inorganic carbonate as much as possible, slightly dissociate some organic matter, then wash it with decarbonized water and freeze-dry it to obtain a pretreated sample.

[0048] S3. Prepare a second phosphoric acid solution with a mass concentration of 55% using the above decarbonized water and orthophosphoric acid, which is prepared to decompose the carbonate of the snail shell.

[0049] S4. Put the above pretreated sample into the second phosphoric acid solution and decompose it under the water bath condition of 72 °C. After 24 hours, when the pH value of the solution is 2 - 3, the decomposition of the carbonate of the snail shell is completed, and the keratin of the snail shell is hydrolyzed into a water-soluble solution to obtain a water-soluble solution containing the keratin of the snail shell. Filter the residue, and then separate and purify it to obtain a keratin sample of the snail shell.

[0050] (Example 6) The method for performing radiocarbon-14 dating using the keratin of the snail shell in this example is as follows: First, extract and purify the keratin sample of the snail shell according to the extraction method provided in Example 1 above. After that, place the purified keratin sample of the snail shell in a 30 mL reactor, add 8 mL of a supersaturated oxidation solution of potassium peroxydisulfate (the same as in Example 1), put it into a vacuum system, evacuate it, then use a natural gas spray gun to seal the reactor, place the reactor in a water bath container at 100 °C and perform a water bath reaction for 1 hour, freeze-collect the CO2 gas, record the gas pressure, and calculate the carbon content of the keratin of the snail shell.

[0051] Specifically, 1.4 mg of Fe2O3 was weighed and placed into a reaction tube. After evacuation, the reaction tube was heated in an electric furnace at 600 °C for 10 minutes, filled with 750 mbar of high-purity H2, and Fe2O3 was reduced to iron. Once the purification of the Fe2O3 sample was completed, it was evacuated to 10 -5 mbar, and the collected sample CO2 was transferred into the reaction tube using a cold trap at -160 °C. CO2 was released, its pressure value was recorded, filled with high-purity hydrogen gas, CO2 was released and mixed with H2, and heated and reacted at 600 °C to synthesize graphite for 14 C Press target was performed for accelerator measurement. During the entire sample manufacturing process, quality control was carried out using a standard chronometric substance with the same carbon amount as the sample.

[0052] According to the methods provided in Example 1 and Example 6 above, instead of the keratin of the snail shell, sodium saccharin, sodium sorbate, sugar, and oxalic acid were used to measure δ 13 C and F 14 C values (the ratio of the 14 C concentration of the sample to the 14 C concentration of local plants or the atmosphere), and it was evaluated whether the oxidation method using the above potassium peroxydisulfate supersaturated oxidation solution could oxidize such water-soluble substances. The specific measurement results are shown in FIGS. 1 and 2. As can be seen from the results, the organic carbon (OC) in the keratin of the snail shell was separated using the potassium peroxydisulfate oxidation method, and sodium saccharin, sodium sorbate, sugar, and oxalic acid were used as reference materials to conduct a strict verification on the reliability of the isotope. Most of the standardized differences in the data were all less than 1, the difference between the test value and the standard value was small, within the acceptable error range, and there was no statistical significance.

[0053] Also, according to the methods provided in Example 1 and Example 6 above, the results of measuring the F 14 C values of the shell carbonates and keratins of modern living snails with different attributes in different regions of China are shown in FIG. 3. Compared with the shell carbonates of snails, the F 14 C value of the keratin of the snail shell is the F 14F of the keratin of the shells of snails of different genera and sizes, close to the C value 14 Since the difference in C values is small, highly reliable 14 It can be used as a C dating material.

[0054] Based on the above desirable embodiments according to the present invention, those skilled in the art can make various changes and modifications without departing from the technical idea of the present invention according to the above description. The technical scope of the present invention is not limited to the content of the specification.

Claims

1. The application of keratin of the shell of a snail in the radiocarbon 14 dating, wherein the method for extracting the keratin of the shell of the snail is, collecting a sample of the shell of the snail and performing crushing and washing treatments to obtain the washed shell of the snail; sequentially immersing the washed shell of the snail in a hydrogen peroxide solution and a first phosphoric acid solution, then washing with decarbonized water and freeze-drying to obtain a pretreated sample; preparing a second phosphoric acid solution with decarbonized water and orthophosphoric acid; putting the pretreated sample into the second phosphoric acid solution for decomposition to obtain a water-soluble solution containing the keratin of the shell of the snail, filtering the residue, and then separating and purifying to obtain a keratin sample of the shell of the snail. The application of keratin of the shell of a snail in the radiocarbon 14 dating is characterized by including the above steps.

2. The application according to claim 1, characterized in that the mass concentration of the hydrogen peroxide solution is 3% to 7%.

3. The application according to claim 1, characterized in that the mass concentration of the first phosphoric acid solution is 1% to 3%.

4. The method for preparing the decarbonized water is, mixing ultrapure water and a supersaturated oxidation solution of potassium peroxydisulfate, performing a water bath reaction to obtain a reacted solution; performing recrystallization treatment on the reacted solution to obtain decarbonized water. The application according to claim 1 is characterized by including the above steps.

5. The method for performing recrystallization treatment is, heating the obtained decarbonized water to 35 to 45 °C and gradually adding potassium peroxydisulfate until saturation; after cooling to room temperature, cooling at 3 to 5 °C to promote the crystallization of potassium peroxydisulfate to obtain crystals; subsequently, filtering, washing the crystals with cold decarbonized water, repeating the recrystallization process multiple times to achieve a purification effect, and freeze-drying potassium peroxydisulfate. The application according to claim 4 is characterized by including the above steps.

6. The supersaturated oxidation solution of potassium peroxydisulfate contains potassium peroxydisulfate, ultrapure water and a third phosphoric acid solution. The mass concentration of the third phosphoric acid solution is 80% to 90%. In the supersaturated oxidation solution of potassium peroxydisulfate, the volume ratio of the third phosphoric acid solution to ultrapure water is (1.5 to 2.5):

1. The application according to claim 4 is characterized by the above.

7. The application according to claim 4, characterized in that the temperature of the water bath reaction is 100 °C.

8. The application according to claim 1, characterized in that the mass concentration of the second phosphoric acid solution is 40 to 60%.

9. The application according to claim 1, characterized in that the decomposition condition is a water bath condition at 65 to 75 °C.

10. A method for performing radiocarbon 14 dating using the keratin of the shell of a snail is Place the keratin sample of the shell of the refined snail in a reactor, add a supersaturated oxidation solution of potassium peroxydisulfate, introduce it into a vacuum system, evacuate, and then perform a water bath reaction, CO ２ The application according to claim 1, characterized by including the steps of freeze-collecting the gas, recording the gas pressure, and calculating the carbon content of the keratin of the shell of the snail.

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