Oxygen stable isotope concentration measuring device and method

Abstract

The invention discloses an oxygen stable isotope concentration measuring device and method, and belongs to the technical field of isotope concentration measurement, the oxygen stable isotope concentration measuring device comprises a first gas pipeline, a second gas pipeline, a third gas pipeline and a fourth gas pipeline which are connected in parallel; the first gas pipeline is connected with a carbon dioxide storage bottle; the second gas pipeline is connected with a vacuum pump; the third gas pipeline is connected with a first reaction bottle; the fourth gas pipeline is connected with a cold hydrazine; the outlet end of the parallel connection position of the first gas pipeline, the second gas pipeline, the third gas pipeline and the fourth gas pipeline is connected with the inlet end of a second reaction bottle after sequentially passing through a tenth valve, a first gas sample collecting bottle and an eleventh valve, and the inlet end of the second reaction bottle is connected with an oxygen storage bottle; and the outlet end of the second reaction bottle is connected with a second gas sample collection bottle through a carbon dioxide liquid nitrogen cold hydrazine. The device is convenient to use, external interference factors are reduced during measurement, the measurement result is more accurate, and the measurement efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of isotope concentration measurement, and in particular relates to a device and method for measuring oxygen stable isotope concentration. Background Art

[0002] Oxygen has 17 isotopes, 3 of which are stable. 16 O. 17 O. 18 O.

[0003] The stable isotopes of oxygen in carbon dioxide are 16 O and 18 O. With the continuous development of testing technology, there are methods for measuring the concentration of stable isotopes of oxygen in carbon dioxide. However, in the existing technology, the test efficiency is low during the experimental process of measuring the concentration of stable isotopes of oxygen in carbon dioxide, and it is easily affected by external interference, which affects the measurement results. Summary of the invention

[0004] In order to solve the above problems, the present invention provides an oxygen stable isotope concentration measurement device and method, which adopts the following technical solutions:

[0005] An oxygen stable isotope concentration measuring device comprises a first gas pipeline, a second gas pipeline, a third gas pipeline and a fourth gas pipeline connected in parallel;

[0006] The first gas pipeline is connected to a carbon dioxide storage bottle; the second gas pipeline is connected to a vacuum pump; the third gas pipeline is connected to a first reaction bottle; the fourth gas pipeline is connected to a cold hydrazine;

[0007] The outlet ends of the parallel connection of the first gas pipeline, the second gas pipeline, the third gas pipeline and the fourth gas pipeline are connected to the inlet end of the second reaction bottle through the tenth valve, the first gas sample collection bottle and the eleventh valve in sequence, the inlet end of the second reaction bottle is connected to the oxygen storage bottle, and the outlet end of the second reaction bottle is connected to the second gas sample collection bottle through carbon dioxide liquid nitrogen cooling hydrazine.

[0008] Further, the connection between the first end of the first gas pipeline and the first end of the second gas pipeline is set as the first connection, and the connection between the second end of the first gas pipeline and the second end of the second gas pipeline is set as the second connection;

[0009] The first gas pipeline is provided with a first valve and a second valve; the first valve is provided between the first end of the carbon dioxide storage bottle and the first connection, and the second valve is provided between the second end of the carbon dioxide storage bottle and the second connection;

[0010] The second gas pipeline is provided with a third valve and a fourth valve; the third valve is provided between the first end of the vacuum pump and the first connection, and the fourth valve is provided between the second end of the vacuum pump and the second connection.

[0011] Further, the connection point between the first end of the third gas pipeline and the first end of the fourth gas pipeline is set as the third connection point, and the connection point between the second end of the third gas pipeline and the second end of the fourth gas pipeline is set as the fourth connection point;

[0012] The third gas pipeline is provided with a fifth valve and a sixth valve; the fifth valve is arranged between the first end of the first reaction bottle and the third connection, and the sixth valve is arranged between the second end of the first reaction bottle and the fourth connection.

[0013] Furthermore, the cold hydrant includes a first cold hydrant and a second cold hydrant connected in series on the fourth gas pipeline; a seventh valve is arranged between the first end of the first cold hydrant and the third connection point, an eighth valve is arranged between the second end of the first cold hydrant and the first end of the second cold hydrant, and a ninth valve is arranged between the second end of the second cold hydrant and the fourth connection point.

[0014] Furthermore, the heating temperature of the second reaction bottle is 500°C-1000°C.

[0015] Furthermore, a thirteenth valve is provided between the oxygen storage bottle and the second reaction bottle.

[0016] Furthermore, a water pipe is wound around the outer wall of the first reaction bottle, and the water pipe is connected to a constant temperature water bath.

[0017] Furthermore, a method for measuring the concentration of oxygen stable isotopes is provided, using the above-mentioned device for measuring the concentration of oxygen stable isotopes, the method comprising the following steps:

[0018] S1. Open the third valve, the fourth valve, the fifth valve and the sixth valve, and close the other valves. Fill the first reaction bottle with the liquid sample, freeze the liquid sample in the container using a cold trap at -60°C to -80°C, start the vacuum pump to pump out the air therein, and repeat the thawing-freezing-pumping process to remove the air dissolved in the liquid sample;

[0019] S2, put a liquid nitrogen cold trap at -160°C to -200°C on the first reaction bottle, open the first valve and the second valve at the same time to transfer a certain amount of carbon dioxide into the first reaction bottle, then close the first valve, the second valve, the third valve, the fourth valve, the fifth valve and the sixth valve, seal the first reaction bottle and separate it from the vacuum system, remove the liquid nitrogen cold trap at -160°C to -200°C, wrap a water pipe around the outer wall of the first reaction bottle, and connect the water pipe to a constant temperature water bath until carbon dioxide and water reach a complete equilibrium fractionation state;

[0020] S3, remove the water pipe on the outer wall of the first reaction bottle, put on a liquid nitrogen cold trap at -160℃ to -200℃ to freeze the liquid sample and carbon dioxide, and then adjust the temperature of the liquid nitrogen cold trap to -60℃ to -80℃, so that the carbon dioxide escapes while the liquid sample continues to remain frozen; then open the fifth valve and the seventh valve to diffuse the carbon dioxide in the container into the first cold hydrazine at -160℃ to -200℃ for 5 to 10 minutes, then adjust the temperature of the first cold hydrazine to -60℃ to -80℃ and open the eighth valve and the ninth valve to allow the carbon dioxide to escape and transfer to the second cold hydrazine at -160℃ to -200℃ for 4 to 6 minutes, open the sixth valve and the ninth valve, repeat the steps of the first cold hydrazine to the second cold hydrazine for multiple times, open the tenth valve, and finally freeze and collect the carbon dioxide into the first gas sample collection bottle for sealing, and then close the tenth valve;

[0021] S4. Open the eleventh valve, freeze the carbon dioxide at -160℃ to -200℃ in the first gas sample collection bottle and transfer it to the second reaction bottle with a sponge platinum catalyst placed at the bottom, then open the thirteenth valve to quickly transfer the same volume of oxygen as the carbon dioxide to the second reaction bottle, close the eleventh valve and the thirteenth valve, seal and then increase the temperature to release the carbon dioxide; after the two gases are sealed and balanced at 700℃ to 800℃ for a period of time, open the twelfth valve, the carbon dioxide is frozen in the carbon dioxide liquid nitrogen cold trap, and the oxygen is collected in the second gas sample collection bottle with a built-in 5A molecular sieve at a low temperature of -160℃ to -200℃ for 10 minutes; the second gas sample collection bottle is separated from the equilibrium fractionation system, and the second gas sample collection bottle is heated at 80℃ for 5 to 10 minutes to fully release the oxygen adsorbed by the molecular sieve, and the value of oxygen stable isotopes is tested on the machine after cooling.

[0022] Beneficial effects:

[0023] The device is easy to use, reduces external interference factors such as water vapor during measurement, improves measurement efficiency, and makes it possible to measure stable isotopes of oxygen in carbon dioxide. 16 O and 18 The results of O concentration are more accurate, reducing measurement errors and improving measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the oxygen stable isotope concentration measuring device of the present invention;

[0025] Among them, 1. the first pipeline; 2. the second pipeline; 3. the third pipeline; 4. the fourth pipeline; 5. the carbon dioxide storage bottle; 6. the vacuum pump; 7. the first reaction bottle; 8. the first gas sample collection bottle; 9. the oxygen storage bottle; 10. the second reaction bottle; 11. the carbon dioxide liquid nitrogen cold hydrazine; 12. the second gas sample collection bottle; 13. the first cold hydrazine; 14. the second cold hydrazine; 15. the first valve; 16. the second valve; 17. the third valve; 18. the fourth valve; 19. the fifth valve; 20. the sixth valve; 21. the seventh valve; 22. the eighth valve; 23. the ninth valve; 24. the tenth valve; 25. the eleventh valve; 26. the twelfth valve; 27. the thirteenth valve. DETAILED DESCRIPTION

[0026] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below.

[0027] Example 1

[0028] Reference Figure 1 , an oxygen stable isotope concentration measuring device, comprising a first gas pipeline 1, a second gas pipeline 2, a third gas pipeline 3 and a fourth gas pipeline 4 connected in parallel;

[0029] The first gas pipeline 1 is connected to a carbon dioxide storage bottle 5; the second gas pipeline 2 is connected to a vacuum pump 6; the third gas pipeline 3 is connected to a first reaction bottle 7; the fourth gas pipeline 4 is connected to a cold hydrazine;

[0030] The outlet ends of the parallel connection of the first gas pipeline 1, the second gas pipeline 2, the third gas pipeline 3 and the fourth gas pipeline 4 are connected to the inlet end of the second reaction bottle 10 through the tenth valve 24, the first gas sample collection bottle 8 and the eleventh valve 25 in sequence. The inlet end of the second reaction bottle 10 is connected to the oxygen storage bottle 9, and the outlet end of the second reaction bottle 10 is connected to the second gas sample collection bottle 12 through the carbon dioxide liquid nitrogen cold hydrazine 11.

[0031] The first reaction bottle is used to hold the liquid sample, and the second reaction bottle 10 is preferably a quartz reaction bottle.

[0032] In this embodiment, the connection between the first end of the first gas pipeline 1 and the first end of the second gas pipeline 2 is set as the first connection, and the connection between the second end of the first gas pipeline 1 and the second end of the second gas pipeline 2 is set as the second connection;

[0033] The first gas pipeline 1 is provided with a first valve 15 and a second valve 16; the first valve 15 is provided between the first end and the first connection of the carbon dioxide storage bottle 5, and the second valve 16 is provided between the second end and the second connection of the carbon dioxide storage bottle 5;

[0034] A third valve 17 and a fourth valve 18 are provided on the second gas pipeline 2 ; the third valve 17 is provided between the first end and the first connection of the vacuum pump 6 , and the fourth valve 18 is provided between the second end and the second connection of the vacuum pump 6 .

[0035] In this embodiment, the connection between the first end of the third gas pipeline 3 and the first end of the fourth gas pipeline 4 is set as the third connection, and the connection between the second end of the third gas pipeline 3 and the second end of the fourth gas pipeline 4 is set as the fourth connection;

[0036] A fifth valve 19 and a sixth valve 20 are provided on the third gas pipeline 3; the fifth valve 19 is provided between the first end of the first reaction bottle 7 and the third connection, and the sixth valve 20 is provided between the second end of the first reaction bottle 7 and the fourth connection.

[0037] In this embodiment, the cold hydrant includes a first cold hydrant 13 and a second cold hydrant 14 connected in series on the fourth gas pipeline 4; a seventh valve 21 is arranged between the first end of the first cold hydrant 13 and the third connection point, an eighth valve 22 is arranged between the second end of the first cold hydrant 13 and the first end of the second cold hydrant 14, and a ninth valve 23 is arranged between the second end of the second cold hydrant 14 and the fourth connection point.

[0038] Through the above technical solution, the carbon dioxide in the system circulates multiple times in the two cold traps, so as to remove the remaining water vapor as much as possible to ensure the purity of the carbon dioxide and avoid the subsequent carbon dioxide-oxygen equilibrium exchange and instrument test analysis being interfered by water vapor.

[0039] In this embodiment, the heating temperature of the second reaction bottle 10 is 500°C-1000°C.

[0040] Wherein, sponge platinum is placed at the bottom of the second reaction bottle 10 as a catalyst.

[0041] Through the above technical solution, the reaction in the second reaction bottle 10 is catalyzed by the sponge platinum catalyst to accelerate the reaction rate.

[0042] In this embodiment, a thirteenth valve 27 is provided between the oxygen storage bottle 9 and the second reaction bottle 10 .

[0043] In this embodiment, a water pipe is wound around the outer wall of the first reaction bottle 7, and the water pipe is connected to a constant temperature water bath.

[0044] Through the above technical solution, a detachable water pipe is wound around the outer wall of the first reaction bottle 7, and the water pipe is connected to a constant temperature water bath to ensure that the carbon dioxide and the liquid sample reach a complete equilibrium fractionation state.

[0045] Example 2

[0046] In this embodiment, a method for measuring the concentration of oxygen stable isotopes is used, using the oxygen stable isotope concentration measuring device of embodiment 1, taking carbon dioxide gas as an example, to measure the oxygen stable isotope concentration in carbon dioxide. 16 O and 18 O concentration, where the stable isotope of oxygen contained in carbon dioxide is 16 O and 18 O, the method comprises the following steps:

[0047] S1, open the third valve 17, the fourth valve 18, the fifth valve 19 and the sixth valve 20, and close the other valves, fill the first reaction bottle 7 with a liquid sample, freeze the liquid sample in the container using a cold trap at -60°C to -80°C, start the vacuum pump 6 to pump out the air therein, and repeat the thawing-freezing-pumping process to remove the air dissolved in the liquid sample;

[0048] The temperature of the liquid sample in the container frozen by cold hydrazine is preferably -80°C;

[0049] S2, put a liquid nitrogen cold trap at -160°C to -200°C on the first reaction bottle 7, open the first valve 15 and the second valve 16 at the same time to transfer a certain amount of carbon dioxide into the first reaction bottle 7, then close the first valve 15, the second valve 16, the third valve 17, the fourth valve 18, the fifth valve 19 and the sixth valve 20, seal the first reaction bottle 7 and separate it from the vacuum system, remove the liquid nitrogen cold trap at -160°C to -200°C, wind a water pipe around the outer wall of the first reaction bottle 7, and connect the water pipe to a constant temperature water bath until the carbon dioxide and the liquid sample reach a complete equilibrium fractionation state;

[0050] Wherein, the temperature of the liquid nitrogen cold trap outside the first reaction bottle 7 is preferably -200°C;

[0051] S3, remove the water pipe on the outer wall of the first reaction bottle 7, put on a liquid nitrogen cold trap at -160℃ to -200℃ to freeze the liquid sample and carbon dioxide, and then adjust the temperature of the liquid nitrogen cold trap to -60℃ to -80℃, so that the carbon dioxide escapes while the liquid sample continues to remain frozen; then open the fifth valve 19 and the seventh valve 21, so that the carbon dioxide in the container diffuses into the first cold hydrazine 13 at -160℃ to -200℃, for 5 to 10 minutes, then adjust the temperature of the first cold hydrazine 13 to -60℃ to -80℃ and open the eighth valve 22 and the ninth valve 23, so that the carbon dioxide escapes and is transferred to the second cold hydrazine 14 at -160℃ to -200℃, for 4 to 6 minutes, open the sixth valve 20 and the ninth valve 23, repeat the steps of the first cold hydrazine 13 to the second cold hydrazine 14 for multiple times, open the tenth valve 24, and finally freeze and collect the carbon dioxide into the first gas sample collection bottle 8 for sealing, and then close the tenth valve 24;

[0052] Among them, the preferred implementation steps are to remove the water liquid sample tube on the outer wall of the first reaction bottle 7, put on a -200°C liquid nitrogen cold trap to freeze the liquid sample and carbon dioxide, and then adjust the temperature of the liquid nitrogen cold trap to -80°C, so that the carbon dioxide escapes and the liquid sample continues to remain in a frozen state; then open the fifth valve 19 and the seventh valve 21, so that the carbon dioxide in the container diffuses into the first cold hydrazine 13 at -200°C for 5 minutes, then adjust the temperature of the first cold hydrazine 13 to -80°C and open the eighth valve 22 and the ninth valve 23, so that the carbon dioxide escapes and is transferred to the second cold hydrazine 14 at -200°C for 4 minutes, open the sixth valve 20 and the ninth valve 23, repeat the steps of the first cold hydrazine 13 to the second cold hydrazine 14 multiple times, open the tenth valve 24, and finally freeze and collect the carbon dioxide into the first gas sample collection bottle 8 for sealing, and then close the tenth valve 24;

[0053] S4, open the eleventh valve 25, freeze the carbon dioxide at -160℃ to -200℃ in the first gas sample collection bottle 8 to the second reaction bottle 10 with a sponge platinum catalyst placed at the bottom, open the thirteenth valve 27 to quickly transfer the same volume of oxygen as the carbon dioxide to the second reaction bottle 10, close the eleventh valve 25 and the thirteenth valve 27, seal and heat to release the carbon dioxide; after the two gases are sealed and balanced at 700℃ to 800℃ for a period of time, open the twelfth valve 26, the carbon dioxide is frozen in the carbon dioxide liquid nitrogen cold trap, and the oxygen is collected in the second gas sample collection bottle 12 with a built-in 5A molecular sieve at a low temperature of -160℃ to -200℃ for 10 minutes; the second gas sample collection bottle 12 is separated from the equilibrium fractionation system, and the second gas sample collection bottle 12 is heated at 80℃ for 5 to 10 minutes to fully release the oxygen adsorbed by the molecular sieve, and then cooled and tested for oxygen stable isotopes on the machine. 16 O and 18 The value of O.

[0054] Among them, the preferred implementation steps are to open the eleventh valve 25, freeze the carbon dioxide at -200°C in the first gas sample collection bottle 8 into the second reaction bottle 10 with a sponge platinum catalyst placed at the bottom, open the thirteenth valve 27 to quickly transfer the same volume of oxygen as the carbon dioxide to the second reaction bottle 10, close the eleventh valve 25 and the thirteenth valve 27, and heat up after sealing to release the carbon dioxide; after the two gases are sealed and balanced for 30 minutes under 750°C, open the twelfth valve 26, the carbon dioxide is frozen in the carbon dioxide liquid nitrogen cold trap, and the oxygen is collected in the second gas sample collection bottle 12 with a built-in 5A molecular sieve under a low temperature of -200°C for 10 minutes; the second gas sample collection bottle 12 is separated from the equilibrium fractionation system, and the second gas sample collection bottle 12 is heated at 80°C for 8 minutes to fully release the oxygen adsorbed by the molecular sieve, and then cooled and tested for oxygen stable isotopes on the machine. 16 O and 18 The value of O.

[0055] Through the above technical solution, the entire reaction is carried out in a closed space, reducing the interference of the external environment and improving the accuracy of the measurement.

[0056] The above description is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any slight modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A device for measuring the concentration of oxygen stable isotopes, It is characterized in that comprising a first gas pipeline, a second gas pipeline, a third gas pipeline and a fourth gas pipeline connected in parallel; The first gas pipeline is connected to a carbon dioxide storage bottle; the second gas pipeline is connected to a vacuum pump; the third gas pipeline is connected to a first reaction bottle; the fourth gas pipeline is connected to a cold hydrazine; The outlet ends of the parallel connection of the first gas pipeline, the second gas pipeline, the third gas pipeline and the fourth gas pipeline are connected to the inlet end of the second reaction bottle through the tenth valve, the first gas sample collection bottle and the eleventh valve in sequence, the inlet end of the second reaction bottle is connected to the oxygen storage bottle, and the outlet end of the second reaction bottle is connected to the second gas sample collection bottle through carbon dioxide liquid nitrogen cooling hydrazine.

2. The oxygen stable isotope concentration measuring device according to claim 1, It is characterized in that The connection between the first end of the first gas pipeline and the first end of the second gas pipeline is set as a first connection, and the connection between the second end of the first gas pipeline and the second end of the second gas pipeline is set as a second connection; The first gas pipeline is provided with a first valve and a second valve; the first valve is provided between the first end of the carbon dioxide storage bottle and the first connection, and the second valve is provided between the second end of the carbon dioxide storage bottle and the second connection; The second gas pipeline is provided with a third valve and a fourth valve; the third valve is provided between the first end of the vacuum pump and the first connection, and the fourth valve is provided between the second end of the vacuum pump and the second connection.

3. The oxygen stable isotope concentration measuring device according to claim 1, It is characterized in that The connection between the first end of the third gas pipeline and the first end of the fourth gas pipeline is set as the third connection, and the connection between the second end of the third gas pipeline and the second end of the fourth gas pipeline is set as the fourth connection; The third gas pipeline is provided with a fifth valve and a sixth valve; the fifth valve is arranged between the first end of the first reaction bottle and the third connection, and the sixth valve is arranged between the second end of the first reaction bottle and the fourth connection.

4. The oxygen stable isotope concentration measuring device according to claim 3, It is characterized in that The cold hydrant includes a first cold hydrant and a second cold hydrant connected in series on the fourth gas pipeline; a seventh valve is arranged between the first end of the first cold hydrant and the third connection point, an eighth valve is arranged between the second end of the first cold hydrant and the first end of the second cold hydrant, and a ninth valve is arranged between the second end of the second cold hydrant and the fourth connection point.

5. The oxygen stable isotope concentration measuring device according to claim 1, It is characterized in that The heating temperature of the second reaction bottle is 500°C-1000°C.

6. The oxygen stable isotope concentration measuring device according to claim 1, It is characterized in that A thirteenth valve is provided between the oxygen storage bottle and the second reaction bottle.

7. The oxygen stable isotope concentration measuring device according to claim 1, It is characterized in that A water pipe is wound around the outer wall of the first reaction bottle, and the water pipe is connected to a constant temperature water bath.

8. A method for measuring oxygen stable isotope concentration, It is characterized in that Using the oxygen stable isotope concentration measuring device according to any one of claims 1 to 7, the method comprises the following steps: S1. Open the third valve, the fourth valve, the fifth valve and the sixth valve, and close the other valves. Fill the first reaction bottle with the liquid sample, freeze the liquid sample in the container using a cold trap at -60°C to -80°C, start the vacuum pump to pump out the air therein, and repeat the thawing-freezing-pumping process to remove the air dissolved in the liquid sample; S2, put a liquid nitrogen cold trap at -160°C to -200°C on the first reaction bottle, open the first valve and the second valve at the same time to transfer a certain amount of carbon dioxide into the first reaction bottle, then close the first valve, the second valve, the third valve, the fourth valve, the fifth valve and the sixth valve, seal the first reaction bottle and separate it from the vacuum system, remove the liquid nitrogen cold trap at -160°C to -200°C, wrap a water pipe around the outer wall of the first reaction bottle, and connect the water pipe to a constant temperature water bath until carbon dioxide and water reach a complete equilibrium fractionation state; S3, remove the water pipe on the outer wall of the first reaction bottle, put on a liquid nitrogen cold trap at -160℃ to -200℃ to freeze the liquid sample and carbon dioxide, and then adjust the temperature of the liquid nitrogen cold trap to -60℃ to -80℃, so that the carbon dioxide escapes while the liquid sample continues to remain frozen; then open the fifth valve and the seventh valve to diffuse the carbon dioxide in the container into the first cold hydrazine at -160℃ to -200℃ for 5 to 10 minutes, then adjust the temperature of the first cold hydrazine to -60℃ to -80℃ and open the eighth valve and the ninth valve to allow the carbon dioxide to escape and transfer to the second cold hydrazine at -160℃ to -200℃ for 4 to 6 minutes, open the sixth valve and the ninth valve, repeat the steps of the first cold hydrazine to the second cold hydrazine for multiple times, open the tenth valve, and finally freeze and collect the carbon dioxide into the first gas sample collection bottle for sealing, and then close the tenth valve; S4. Open the eleventh valve, freeze the carbon dioxide at -160℃ to -200℃ in the first gas sample collection bottle and transfer it to the second reaction bottle with a sponge platinum catalyst placed at the bottom, then open the thirteenth valve to quickly transfer the same volume of oxygen as the carbon dioxide to the second reaction bottle, close the eleventh valve and the thirteenth valve, seal and then increase the temperature to release the carbon dioxide; after the two gases are sealed and balanced at 700℃ to 800℃ for a period of time, open the twelfth valve, the carbon dioxide is frozen in the carbon dioxide liquid nitrogen cold trap, and the oxygen is collected in the second gas sample collection bottle with a built-in 5A molecular sieve at a low temperature of -160℃ to -200℃ for 10 minutes; the second gas sample collection bottle is separated from the equilibrium fractionation system, and the second gas sample collection bottle is heated at 80℃ for 5 to 10 minutes to fully release the oxygen adsorbed by the molecular sieve, and the value of oxygen stable isotopes is tested on the machine after cooling.

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