Air water vapor hydrogen and oxygen isotope analysis method based on portable water vapor extraction device

Abstract

The invention discloses an air water vapor hydrogen and oxygen isotope analysis method based on a portable water vapor extraction device. The method comprises the following steps: S1, assembling all modules and integrating the modules in a light shell; s2, after installation is ready, liquid nitrogen is filled into a Dewar flask, and when the temperature of a first temperature controller reaches 100 DEG C and the temperature of a second temperature controller reaches 45 DEG C, an air pump is started to start to extract water vapor, and timing extraction is conducted; and S3, after timing extraction is finished, closing the first temperature controller, the second temperature controller and the sucking pump, taking out the outer tube from the Dewar flask, waiting for water vapor condensation to obtain a to-be-detected sample, and performing sample analysis by using an isotope ratio mass spectrometer. According to the device disclosed by the invention, 0.8 ml of purified water sample can be stably extracted within 15 minutes under the condition of relatively low relative humidity (50-65%) in an air vapor extraction process, and an efficient vapor condensation technology is a key for realizing rapid water sample collection, so that a reliable guarantee is provided for subsequent hydrogen and oxygen isotope analysis.

Description

Technical Field

[0001] This invention relates to the field of water vapor extraction and detection methods, and in particular to a method for analyzing hydrogen and oxygen isotopes in air water vapor based on a portable water vapor extraction device. Background Technology

[0002] Hydrogen and oxygen isotopes (such as δ) in air water vapor 2 H, δ 18 The determination of oxygen (O) is of great significance in many fields, including environmental science, hydrology, ecology, meteorology, and paleoclimate research. In environmental hydrological research, by measuring the hydrogen and oxygen isotope composition of atmospheric water vapor, the migration paths of water between the atmosphere, the Earth's surface, and groundwater can be traced, revealing processes such as evaporation, condensation, and precipitation. In ecological research, by comparing the isotopic characteristics of plant transpiration water vapor with those of soil water and precipitation, we can understand the water sources and water use efficiency of plants and assess the response of ecosystems to climate change. In meteorological and atmospheric science research, the isotopic characteristics of water vapor differ in different regions; by analyzing water vapor isotopes, the transport paths and mixing processes of water vapor in the atmosphere can be traced.

[0003] Currently, the equipment used for measuring hydrogen and oxygen isotopes in air water vapor mainly includes imported instruments from the Picarro series and Los Gatos Research series. These instruments are typically based on cavity ring-down spectroscopy (CRDS) or off-axis integrating cavity output spectroscopy (OA-ICOS) techniques, providing high-precision isotope measurement data. However, they also have some drawbacks or limitations, mainly including: (1) High cost: These high-end devices are usually very expensive, including not only the purchase cost, but also the subsequent maintenance, calibration and consumable costs.

[0004] (2) Operational complexity: These precision instruments often require professional training to operate and maintain. Users need to have a certain technical background, which may pose significant learning difficulties for non-professionals.

[0005] (3) Poor portability and field adaptability: Although some models are designed with portability and field use in mind, most devices are still more suitable for laboratory environments. These devices may not be suitable for situations that require long-term field deployment or mobile measurement because they have strict requirements for environmental conditions (such as temperature and humidity) and are large in size and difficult to move.

[0006] Based on the above problems, there is an urgent need for an air water vapor extraction and detection device that is low in cost, flexible in use, easy to operate and carry, and less affected by the environment. Summary of the Invention

[0007] The purpose of this invention is to provide a method for analyzing hydrogen and oxygen isotopes in air water vapor based on a portable water vapor extraction device, in order to solve the problems of high cost, complex operation, poor portability and field adaptability, and low water vapor extraction efficiency of the aforementioned air water vapor hydrogen and oxygen isotope measuring equipment.

[0008] To achieve the above objectives, the present invention provides an air water vapor hydrogen and oxygen isotope analysis method based on a portable water vapor extraction device. The sample extraction process of the air water vapor hydrogen and oxygen isotope analysis method is carried out in a portable water vapor extraction device, which includes a condensation module, a temperature control module, a power supply module, an air flow control module, and a lightweight housing. The air flow control module is connected to the power supply module and draws air carrying water vapor into the condensation module for cooling and condensation. The temperature control module is located on the top of the condensation module for temperature control. The condensation module, temperature control module, power supply module, and air flow control module are integrated into the lightweight housing.

[0009] Preferably, the temperature control module includes a first temperature controller and a second temperature controller.

[0010] Preferably, the power module is a portable outdoor power supply, and the air flow control module is an adjustable speed air pump.

[0011] The power module in this invention can be selected according to the actual situation, as long as it can provide power for the operation of the air flow control module. Since this invention is applicable to the field, the above-mentioned portable outdoor power supply can be used, which is convenient to carry and assemble. The air flow control module is mainly used to control the air flow into the condenser module. The above-mentioned adjustable speed air pump can be selected to control the air flow by adjusting the speed.

[0012] Preferably, the condensation module includes an outer tube, an inner tube, a short tube, and a long tube. The outer tube is sleeved outside the inner tube. There is a gap between the bottom end of the inner tube and the inner wall of the outer tube. The top of the inner tube is connected to one end of the short tube. The other end of the short tube is connected to the air pump. One end of the long tube is connected to the top of the outer tube.

[0013] Preferably, the first temperature controller is located on the top of the outer tube, and the second temperature controller is located on the long tube.

[0014] Preferably, the outer tube is placed in a Dewar flask and cooled and condensed using liquid nitrogen.

[0015] In this invention, the condensation module is mainly used to rapidly condense water vapor in the drawn-in air into a liquid state. The liquid sample is used for subsequent testing, and rapid water vapor condensation can be achieved through precise temperature control. The temperature control module is mainly used to display the temperature at different locations on the condensation module, accurately controlling the timing of air being drawn into the condensation module. The air flow control module is mainly used to control the flow rate and speed of air drawn into the condensation module, and the power module provides external power to the air flow control module. For the sake of overall portability, the above components can be integrated into a lightweight shell for easy carrying and use in the field.

[0016] Preferably, the method for analyzing hydrogen and oxygen isotopes in air water vapor includes the following steps: S1: Assemble the condenser module, temperature control module, power supply module and air flow control module and integrate them into a lightweight housing; S2: After installation, fill the Dewar flask with liquid nitrogen, turn on the first temperature controller and the second temperature controller, and when the temperature of the first temperature controller reaches 100°C and the temperature of the second temperature controller reaches 45°C, turn on the vacuum pump to start extracting water vapor and start timing the extraction. S3: After the timing extraction is completed, turn off the first temperature controller, the second temperature controller and the vacuum pump, remove the outer tube from the Dewar flask, wait for the water vapor to condense to obtain the sample to be tested, and use an isotope ratio mass spectrometer to analyze the sample.

[0017] Preferably, in step S2, the air pump extracts water vapor from the air, the air humidity is 50-80%, and the extraction time is 10-30 minutes.

[0018] Preferably, in step S2, the average flow rate of the air pump is ≥3.5L / min.

[0019] Preferably, in step S3, the volume of the sample to be tested is 0.5-2 mL.

[0020] Preferably, the air humidity is 50-65%, the sampling time is 15 minutes, and the volume of the sample to be tested is 0.8 mL.

[0021] Therefore, the present invention provides a method for analyzing hydrogen and oxygen isotopes in air water vapor based on a portable water vapor extraction device, which has the following advantages: (1) The cost of the device of the present invention is only a fraction of that of mainstream instruments on the market. The reduced cost and wider range of applications will help promote the popularization and development of environmental isotope hydrological research and ecological research.

[0022] (2) The device of the present invention uses lightweight materials and a compact design, which is not only lightweight and small in size, but also equipped with a portable power module to ensure the needs of long-term field operations. Its modular design also facilitates quick assembly and disassembly, improving work efficiency. In addition, due to its simple structure, it is relatively easy to maintain, reducing the risk of research interruption due to equipment failure.

[0023] (3) During the air water vapor extraction process, the device of the present invention can stably extract 0.8 ml of pure water sample within 15 minutes even under relatively low humidity (50-65%), which shows that it can operate efficiently under various climatic conditions and meet the scientific research needs in different environments. Efficient water vapor condensation technology is the key to achieving rapid water sample collection, providing a reliable guarantee for subsequent hydrogen and oxygen isotope analysis.

[0024] (4) In addition to being able to operate under various weather conditions, this device also has strong environmental adaptability. For example, it can be used with different external devices (such as LGR laser water isotope analyzers or Thermo Fisher Scientific isotope ratio mass spectrometers) to perform accurate isotope measurements. At the same time, by adjusting the air flow control module, it can adapt to different sampling conditions, thereby obtaining more accurate data.

[0025] (5) The operation process of the air water vapor hydrogen and oxygen isotope analysis method of the present invention is simple and easy for operators to quickly get started. In addition, the accuracy of the final measurement results is ensured by the calibration of the standard sample. This high-precision analysis capability is crucial for a deeper understanding of issues such as climate change, water resource management and ecological protection.

[0026] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0027] Figure 1 This is an assembly diagram of a portable water vapor extraction device. Figure 2 This is a schematic diagram of a portable water vapor extraction device; Figure 3 This is a schematic diagram of the condenser module. Figure 4 This is a physical image of the condenser module; In the diagram: 1. Condensation module; 11. Inner tube; 12. Outer tube; 13. Short tube; 14. Long tube; 2. Air pump; 3. Portable outdoor power supply; 4. Dewar flask; 5. First temperature controller; 6. Second temperature controller. Detailed Implementation

[0028] The present invention will be further described below. It should be noted that this embodiment is based on the present technical solution and provides detailed implementation methods and specific operation processes, but the present invention is not limited to this embodiment.

[0029] Example 1 like Figure 2-4 As shown, this embodiment provides a portable water vapor extraction device based on a modular design. The device includes a condensation module 1, a temperature control module, a power supply module, an air flow control module, and a lightweight outer shell. The air flow control module is connected to the power supply module. The air flow control module draws air carrying water vapor into the condensation module 1 for cooling and condensation. The temperature control module is located on the top of the condensation module 1 for temperature control. The condensation module 1, the temperature control module, the power supply module, and the air flow control module are integrated into the lightweight outer shell.

[0030] The condensation module 1 includes an outer tube 12, an inner tube 11, a short tube 13, and a long tube 14. The outer tube 12 is sleeved outside the inner tube 11. There is a gap between the bottom end of the inner tube 11 and the inner wall of the outer tube 12. The bottom of the outer tube 12 is used to store the liquid sample formed by the condensation of water vapor in the air. The top of the inner tube 11 is connected to one end of the short tube 13. The other end of the short tube 13 is connected to the air pump 2 through a rubber tube. One end of the long tube 14 is connected to the top of the outer tube 12.

[0031] The outer tube 12 is placed in a Dewar flask 4 and cooled and condensed using liquid nitrogen. The temperature control module includes a first temperature controller 5 and a second temperature controller 6. The first temperature controller 5 is located at the top of the outer tube 12, and the second temperature controller 6 is located on the long tube 14. The power module is a portable outdoor power supply 3, and the air flow control module is an adjustable speed air pump 2. The portable outdoor power supply 3 is electrically connected to the air pump 2 to provide power to the air pump 2.

[0032] Example 2 This embodiment provides a method for analyzing hydrogen and oxygen isotopes in air water vapor based on a portable water vapor extraction device, including the following steps: S1: As Figure 1 As shown, the condenser module 1, temperature control module, power supply module and air flow control module are assembled and integrated into a lightweight housing; S2: After installation, fill the Dewar flask 4 with liquid nitrogen, turn on the first temperature controller 5 and the second temperature controller 6. When the temperature of the first temperature controller 5 reaches 100°C and the temperature of the second temperature controller 6 reaches 45°C, turn on the vacuum pump 2 (average flow rate of 5L / min) to start extracting water vapor and start timing the extraction. S3: After the timing extraction is completed, turn off the first temperature controller 5, the second temperature controller 6 and the vacuum pump 2, remove the outer tube from the Dewar flask 4, wait for the water vapor to condense to obtain the sample to be tested, and use an isotope ratio mass spectrometer to analyze the sample.

[0033] Example 3 The analytical method in Example 2 was used for the extraction and testing of water vapor in outdoor air. The specific experimental procedure is as follows: (1) Experimental time and experimental environment The test was conducted at Shenzhen University (Yuehai Campus) on May 27, 2025. The weather was cloudy or overcast (see Table 1 for specific weather conditions), with no rain, which met the basic weather conditions for water vapor extraction.

[0034] Table 1 Experimental Record Sheet

[0035] (2) Experimental procedure The test was conducted three times a day: 9:00 AM, 1:00 PM, and 4:00 PM, as parallel experiments. Before the experiment, the environmental conditions at that time, namely time, temperature, humidity, and weather, were recorded (Table 1).

[0036] Assembly: Assemble the device according to the method in Example 2, see details. Figure 1 .

[0037] Vacuuming: After installation, fill the Dewar flask with liquid nitrogen. Then, turn on the switches of the two temperature controllers. Once the temperatures of the first and second temperature controllers reach the set values ​​of 100℃ and 45℃ respectively, turn on the vacuum pump to begin extracting water vapor and time it for 15 minutes. After the timer expires, turn off the temperature controllers and the vacuum pump. Remove the test tube from the Dewar flask and wait for the water vapor to condense completely to obtain a liquid sample. Transfer the liquid sample to a sample bottle and label it.

[0038] The subsequent two parallel experiments were conducted within the specified time using the same procedure, with the same timing for the evacuation, and the volume of water vapor extracted each time was 0.8 ml.

[0039] (3) Water vapor isotope determination The collected water vapor condensate (the sample to be tested) should be promptly analyzed for hydrogen and oxygen isotope values. The specific procedures are as follows: First, the hydrogen-oxygen isotope ratio of ambient water vapor was measured in real time (9:00, 13:00, 16:00) using an LGR laser water isotope analyzer (IWA-45-EP, Los Gatos Research). After cold trap sampling, different liquid standards were converted into water vapor of similar concentration using an LGR standard water vapor generator (WVISS), and then introduced into the laser water isotope analyzer for measurement to obtain the measured values. Three liquid standards were used in this experiment: GBW04458 (δ... 2 H: -1.7‰, δ 18 O: -0.15‰), GBW04459 (δ 2 H: -63.4‰, δ 18 O: -8.61‰) and GBW04460 (δ 2 H: -144.0‰, δ 18 O: -19.13‰). By establishing a calibration line between the measured values ​​of these three standard samples and their true values, and based on the regression equation of this calibration line, the isotopic measurements of environmental water vapor are converted into true values.

[0040] The liquid samples collected in the cold trap were then analyzed using an isotope ratio mass spectrometer (Delta V Advantage, Thermo Fisher Scientific). Each liquid sample was measured three times. The three liquid standards were measured four times before and after the sample measurement, and the results of the last two measurements were used as the calibration basis. The isotope ratio of the cold trap samples was also corrected using a similar method, and the average of the last two measurements (after correction) was used as the final result. The test results are shown in Table 2.

[0041] Table 2 Hydrogen and oxygen isotope values ​​of water collected from water vapor and atmospheric water vapor

[0042] As can be seen from Table 2, the isotope ratios of atmospheric water vapor and collected water show similar trends as the day progresses, indicating that the hydrogen and oxygen isotope analysis method for air water vapor in this invention is consistent with existing methods and has high accuracy.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for analyzing hydrogen and oxygen isotopes in air water vapor based on a portable water vapor extraction device, characterized in that: The sample extraction process for the air water vapor hydrogen and oxygen isotope analysis method is carried out in a portable water vapor extraction device. The device includes a condensation module, a temperature control module, a power supply module, an air flow control module, and a lightweight housing. The air flow control module is connected to the power supply module. The air flow control module draws air carrying water vapor into the condensation module for cooling and condensation. The temperature control module is located on top of the condensation module to control the temperature. The condensation module, temperature control module, power supply module, and air flow control module are integrated in the lightweight housing.

2. The method for analyzing hydrogen and oxygen isotopes in air water vapor based on a portable water vapor extraction device according to claim 1, characterized in that: The temperature control module includes a first temperature controller and a second temperature controller.

3. The method for analyzing hydrogen and oxygen isotopes in air water vapor based on a portable water vapor extraction device according to claim 2, characterized in that: The power module is a portable outdoor power supply, and the air flow control module is an adjustable speed air pump.

4. The method for analyzing hydrogen and oxygen isotopes in air water vapor based on a portable water vapor extraction device according to claim 3, characterized in that: The condensation module includes an outer tube, an inner tube, a short tube, and a long tube. The outer tube is fitted over the inner tube. There is a gap between the bottom of the inner tube and the inner wall of the outer tube. The top of the inner tube is connected to one end of the short tube. The other end of the short tube is connected to the air pump. One end of the long tube is connected to the top of the outer tube.

5. The method for analyzing hydrogen and oxygen isotopes in air water vapor based on a portable water vapor extraction device according to claim 4, characterized in that: The first temperature controller is located at the top of the outer tube, and the second temperature controller is located on the long tube.

6. The method for analyzing hydrogen and oxygen isotopes in air water vapor based on a portable water vapor extraction device according to claim 5, characterized in that: The outer tube is placed in a Dewar flask and cooled and condensed using liquid nitrogen.

7. A method for analyzing hydrogen and oxygen isotopes in air water vapor based on a portable water vapor extraction device according to any one of claims 1 to 6, characterized in that: Includes the following steps: S1: Assemble the condenser module, temperature control module, power supply module and air flow control module and integrate them into a lightweight housing; S2: After installation, fill the Dewar flask with liquid nitrogen, turn on the first temperature controller and the second temperature controller, and when the temperature of the first temperature controller reaches 100°C and the temperature of the second temperature controller reaches 45°C, turn on the vacuum pump to start extracting water vapor and start timing the extraction. S3: After the timing extraction is completed, turn off the first temperature controller, the second temperature controller and the vacuum pump, remove the outer tube from the Dewar flask, wait for the water vapor to condense to obtain the sample to be tested, and use an isotope ratio mass spectrometer to analyze the sample.

8. The method for analyzing hydrogen and oxygen isotopes in air water vapor based on a portable water vapor extraction device according to claim 7, characterized in that: In step S2, the air pump extracts water vapor from the air, with an air humidity of 50-80%, and the extraction time is 10-30 minutes.

9. The method for analyzing hydrogen and oxygen isotopes in air water vapor based on a portable water vapor extraction device according to claim 7, characterized in that: In step S2, the average flow rate of the air pump is ≥3.5L / min.

10. The method for analyzing hydrogen and oxygen isotopes in air water vapor based on a portable water vapor extraction device according to claim 7, characterized in that: In step S3, the volume of the sample to be tested is 0.5-2 mL.

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