Device for monitoring ozone depleted substances and hydrofluorocarbon in atmosphere

Abstract

The utility model relates to a monitoring device for ozone depleted substances and hydrofluorocarbon in atmosphere, and belongs to the technical field of chromatography-mass spectrometry. According to the scheme, the device mainly comprises a target object trapping pipeline which comprises a trapping module used for trapping a target object in sample gas; the focusing analysis module is used for performing focusing and chromatographic separation on the target object and then performing detection; the analysis pipeline comprises an analysis carrier gas inlet and a trapping switching module, and the trapping switching module is used for enabling the two ends of the trapping module to be connected with the analysis carrier gas inlet and the focusing analysis module respectively; the purification pipeline comprises a capillary chromatographic column purification module, the capillary chromatographic column purification module is used for removing interferents in a target object, and when the purification pipeline is in a first state, the inert gas sequentially passes through the trapping module and the capillary chromatographic column purification module; in the second state, the inert gas sequentially passes through the capillary chromatographic column purification module and the trapping module.

Description

Technical Field

[0001] This invention belongs to the field of chromatography-mass spectrometry analysis technology, specifically a device for monitoring ozone-depleting substances and hydrofluorocarbons in the atmosphere. Background Technology

[0002] Ozone (O3) is concentrated in the stratosphere, with the highest concentration at an altitude of 15 km to 30 km above the Earth's surface; this area is known as the ozone layer. It absorbs most of the ultraviolet radiation from sunlight, especially harmful UVB rays, thus protecting humans and other organisms from these harmful rays. Currently, scientists have discovered ozone-depleting gases in the air, primarily including ozone-depleting substances and fluorinated greenhouse gases. Ozone-depleting substances are... Depleting Substances (ODS) comprise six major classes of halogenated hydrocarbons, such as chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, carbon tetrachloride (CCl4), methyl chloroform (CH3CCl3), and methyl bromide (CH3Br). Fluorine-containing greenhouse gases are abbreviated as F. This includes four of the seven greenhouse gases covered by the Kyoto Protocol of the United Nations Framework Convention on Climate Change (UNFCCC): hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF6), and nitrogen trifluoride (NF3). Especially when dealing with multiple projects and multiple samples, there are common problems such as low dosing efficiency, large dosing errors, and even incorrect dosing.

[0003] Currently, these ozone-depleting compounds are mainly produced industrially, used in refrigeration, cleaning, and foaming processes. To protect the human environment, the Montreal Protocol was signed in 1987, restricting the use and emissions of ozone-depleting substances and chlorofluorocarbons (CFCs) globally. This necessitates monitoring the concentrations of ozone-depleting substances and fluorinated greenhouse gases in the atmosphere mentioned in the Montreal Protocol. However, the concentrations of these substances in the atmosphere are at the ppt (parts per trillion) level, with some concentrations even less than 1 ppt. Therefore, the detection limits and accuracy requirements of monitoring systems are extremely high. Currently, such equipment covers relatively few components, making it difficult to accurately separate target substances from samples, resulting in significant deviations in detection results.

[0004] Patent CN113834884A discloses an online monitoring system for ozone-depleting substances. The technical solution employed is an "online sampling and pre-concentration system using a semiconductor refrigeration combined with a super-adsorbent cold trap, with an online low-temperature Nafion membrane dehydration device connected to the sample injection end. The sampling and pre-concentration system is sequentially connected to a gas chromatograph and a quadrupole mass spectrometer, respectively connected to the workstation computers of the pre-concentration system and the gas chromatograph and quadrupole mass spectrometer." However, this detection system only has a Nafion membrane dehydration device at the sample end, failing to remove moisture from the carrier gas end. Furthermore, it requires pressurizing the ambient air to complete continuous sample injection, and this system only covers the monitoring of 21 ozone-depleting substances. Patent CN116577446A discloses a method, device, and storage medium for detecting ozone-depleting substances in the air; this device requires pressurized sampling due to the use of Nafion tube dehydration technology at the front end, making the sampling structure more complex. Patent CN116465993A discloses a method for identifying and assessing the ecological and environmental damage caused by controlled ozone-depleting substances (ODS). However, this method is only applicable to the qualitative and quantitative analysis of ODS and hydrofluorocarbons in ambient air. Patent CN115494172A discloses a method and apparatus for measuring ODS and fluorinated greenhouse gases in the atmosphere. This method and apparatus can only analyze and measure high-concentration samples and lacks concentration capabilities; therefore, it cannot accurately analyze low-concentration samples qualitatively and quantitatively.

[0005] In summary, existing detection equipment struggles to accurately separate the target analyte from the sample, resulting in significant deviations in the detection results. Utility Model Content

[0006] In view of the above analysis, in order to solve the above problems, the first aspect of this utility model provides a monitoring device for ozone-depleting substances and hydrofluorocarbons in the atmosphere, comprising:

[0007] The target object capture pipeline includes a capture module, which is used to capture the target object in the sample gas;

[0008] The focusing analysis module is used for focusing and chromatographic separation of target analytes before detection.

[0009] The analysis pipeline includes an analysis carrier gas inlet and a trapping switching module, wherein the trapping switching module is used to connect the two ends of the trapping module to the analysis carrier gas inlet and the focusing analysis module, respectively.

[0010] A purification pipeline is provided to remove interfering substances from the target analyte in the trapping module. The purification pipeline includes a capillary column purification module for removing interfering substances from the target analyte. The purification pipeline has a first state and a second state. In the first state, the inert gas passes sequentially through the trapping module and the capillary column purification module. In the second state, the inert gas passes sequentially through the capillary column purification module and the trapping module.

[0011] In some embodiments, a dehydration module is further included, which is disposed on the target collection pipeline and is used to dehydrate the sample gas before the sample gas enters the collection module.

[0012] In some embodiments, the dehydration module includes a first dehydration module and a second dehydration module;

[0013] The target collection pipeline also includes an autosampler, a pump, and a first flow meter. The autosampler is used to connect to the Summa tank. The pump is located at one end near the outlet of the target collection pipeline. The autosampler is connected to the pump in sequence through the first dehydration module, the second dehydration module, the collection module, and the first flow meter.

[0014] The focusing analysis module includes a focusing module, a chromatographic separation module, and a detection unit connected in sequence. The focusing module is used to focus the target analyte and input the target analyte into the chromatographic separation module. The chromatographic separation module is used to perform chromatographic separation on the target analyte and then input it into the detection unit. The inlet of the focusing module is connected to the multi-stage analytical pipeline.

[0015] In some embodiments, a one-to-many selector valve, a first switching valve, and a second switching valve are also included;

[0016] The one-to-many selector valve has a fixed interface and a plurality of selectable interfaces, and the one-to-many selector valve is configured to connect one of the fixed interfaces to one of the selectable interfaces.

[0017] The autosampler is connected to the selection interface S7 of the one-to-many selector valve via the first dehydration module. The fixed interface is connected to the interface P1 of the first switching valve. The interface P2 of the first switching valve is connected to the interface P5 of the second switching valve. The two ends of the trapping module are connected to the interfaces P3 and P6 of the first switching valve, respectively. The interface P4 of the first switching valve is connected to the focusing module. The interface P5 of the first switching valve is connected to the desorption carrier gas inlet. The interface P7 of the first switching valve is connected to the pump via the first flow meter. The interface P8 of the first switching valve is connected to the interface P2 of the second switching valve. The two ends of the second dehydration module are connected to the interfaces P3 and P4 of the second switching valve, respectively. The two ends of the capillary column purification module are connected to the interfaces P6 and P1 of the second switching valve, respectively.

[0018] The first switching valve has an A state and a B state. When the first switching valve is in the A state, only its interfaces P1 and P8, P2 and P3, P4 and P5, and P6 and P7 are connected. When the first switching valve is in the B state, only its interfaces P1 and P2, P3 and P4, P5 and P6, and P7 and P8 are connected.

[0019] The second switching valve has an A state and a B state. When the second switching valve is in the A state, only its interfaces P1 and P6, P2 and P3, and P4 and P5 are connected. When the second switching valve is in the B state, only its interfaces P1 and P2, P4 and P5, and P5 and P6 are connected.

[0020] In some embodiments, the purification pipeline includes an inert gas inlet, a first three-way valve, and a second three-way valve;

[0021] One end of the first three-way valve is connected to one end of the second three-way valve. The other two ends of the first three-way valve are respectively connected to the inert gas inlet and the selection interface S5 of the one-to-many selector valve. The other two ends of the second three-way valve are respectively connected to the interface P7 of the first switching valve and the first flow meter.

[0022] The first three-way valve is configured to connect the inert gas inlet to the one-to-many selector valve or to connect the inert gas inlet to the second three-way valve;

[0023] The second three-way valve is configured to connect the first three-way valve to the first switching valve or to connect the first switching valve to the first flow meter. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this specification. For those skilled in the art, other drawings can be obtained based on these drawings.

[0025] Figure 1 A schematic diagram of the structure of the ozone-depleting substances and hydrofluorocarbons monitoring device in the atmosphere provided for an embodiment of this utility model;

[0026] Figure 2 These are the chromatograms of steps SC1 to SC8 in the embodiments of this utility model;

[0027] Figure 3 These are chromatograms of steps SD1 to SD10 in the embodiments of this utility model. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] Example 1

[0030] Even after purification by the primary and secondary dehydration modules and the collection module, some difficult-to-remove interfering substances remain in the enriched target substances. These interfering substances significantly hinder the quantitative detection of some low- and medium-boiling-point target substances. To address this issue, Embodiment 1 of this invention employs a staged analysis. However, due to the difficulty in determining the boiling point boundary between the two stages in the staged analysis, the separation results of some target substances overlap between the two stages, resulting in some target substances exhibiting two peaks of different sizes. To solve this problem, this embodiment provides a monitoring device for ozone-depleting substances and hydrofluorocarbons in the atmosphere, such as... Figure 2 As shown, it includes:

[0031] The target object capture pipeline includes a capture module 203, which is used to capture the target object in the sample gas;

[0032] The focusing analysis module is used for focusing and chromatographic separation of target analytes before detection.

[0033] The analysis pipeline includes an analysis carrier gas inlet 402 and a collection switching module, wherein the collection switching module is used to connect the two ends of the collection module 203 to the analysis carrier gas inlet 402 and the focusing analysis module, respectively.

[0034] A purification pipeline is provided to remove interfering substances from the target analyte in the trapping module. The purification pipeline includes a capillary column purification module 204, which is used to remove interfering substances from the target analyte. The purification pipeline has a first state and a second state. In the first state, the inert gas passes sequentially through the trapping module 203 and the capillary column purification module 204. In the second state, the inert gas passes sequentially through the capillary column purification module 204 and the trapping module 203.

[0035] In some embodiments, a dehydration module is further included, which is disposed on the target collection pipeline and is used to dehydrate the sample gas before the sample gas enters the collection module.

[0036] In some embodiments, the dehydration module includes a first dehydration module 201 and a second dehydration module 202;

[0037] The target collection pipeline also includes an autosampler 101, a pump 109, and a first flow meter 105. The autosampler 101 is used to connect to the Summa tank. The pump 109 is located at one end near the outlet of the target collection pipeline. The autosampler 101 is connected to the pump 109 in sequence through the first dehydration module 201, the second dehydration module 202, the collection module 203, and the first flow meter 105.

[0038] The focusing analysis module includes a focusing module 302, a chromatographic separation module, and a detection unit 405 connected in sequence. The focusing module 302 is used to focus the target analyte and input the target analyte into the chromatographic separation module. The chromatographic separation module is used to perform chromatographic separation on the target analyte and then input it into the detection unit. The inlet of the focusing module is connected to the multi-stage analytical pipeline.

[0039] The chromatographic separation module includes a chromatographic column 401, a condenser 404, and a heat exchanger 403. The condenser 404 and heat exchanger 403 are connected to the chromatographic column 401. One end of the chromatographic column 401 is connected to the detection unit, and the other end is connected to the focusing module 302 via an inert two-way valve. After chromatographic separation of the target analyte, the chromatographic separation module inputs the analyte into the detection unit 501. The inlet of the focusing module 302 is connected to the multi-stage analytical pipeline. Specifically, the focusing analysis module is used to refocus the target analyte at low temperature using the focusing module 302, while simultaneously controlling the programmed temperature rise, allowing the target analyte to flow into the detection unit 501 one by one. It should be noted that "low temperature" here refers to... The environment is 15℃~15℃. The detection unit 501 includes an ion source and an ion multiplier. The ion source fragments the target molecule into ions; the ion fragments enter the ion multiplier to form a current signal, and the ion multiplier is used to receive, amplify and form a chromatogram of the current signal, which facilitates qualitative and quantitative analysis.

[0040] In some embodiments, a multi-select valve 102, a first switching valve 103, and a second switching valve 104 are also included;

[0041] The one-to-many selector valve 102 has a fixed interface and a plurality of selector interfaces, and the one-to-many selector valve 102 is configured to enable one of the fixed interfaces to communicate with one of the selector interfaces.

[0042] The autosampler 101 is connected to the selection interface S7 of the one-to-many selector valve via the first dehydration module 201. The fixed interface is connected to the interface P1 of the first switching valve. The interface P2 of the first switching valve is connected to the interface P5 of the second switching valve. The two ends of the trapping module 203 are connected to the interfaces P3 and P6 of the first switching valve, respectively. The interface P4 of the first switching valve is connected to the focusing module. The interface P5 of the first switching valve is connected to the desorption carrier gas inlet. The interface P7 of the first switching valve is connected to the pump via the first flow meter. The interface P8 of the first switching valve is connected to the interface P2 of the second switching valve. The two ends of the second dehydration module 202 are connected to the interfaces P3 and P4 of the second switching valve, respectively. The two ends of the capillary column purification module 204 are connected to the interfaces P6 and P1 of the second switching valve, respectively.

[0043] The first switching valve 103 has an A state and a B state. When the first switching valve is in the A state, only its interfaces P1 and P8, P2 and P3, P4 and P5, and P6 and P7 are connected. When the first switching valve is in the B state, only its interfaces P1 and P2, P3 and P4, P5 and P6, and P7 and P8 are connected.

[0044] The second switching valve 104 has an A state and a B state. When the second switching valve is in the A state, only its ports P1 and P6, ports P2 and P3, and ports P4 and P5 are connected. When the second switching valve is in the B state, only its ports P1 and P2, ports P4 and P5, and ports P5 and P6 are connected.

[0045] Optionally, the one-to-many selector valve 102 can be an eight-in-one-out selector valve, the first switching valve 103 can be an eight-position switching valve, and the second switching valve 104 can be a six-position switching valve.

[0046] In some embodiments, the purification pipeline includes an inert gas inlet, a first three-way valve 110, and a second three-way valve 112; the first three-way valve 110 is, for example, a two-position three-way solenoid valve, and the second three-way valve 112 is, for example, a silanized three-way valve.

[0047] One end of the first three-way valve 110 is connected to one end of the second three-way valve 112. The other two ends of the first three-way valve 110 are respectively connected to the inert gas inlet and the selection interface S5 of the one-to-many selector valve. The other two ends of the second three-way valve 112 are respectively connected to the interface P7 of the first switching valve and the first flow meter.

[0048] The first three-way valve 110 is configured to connect the inert gas inlet to the one-to-many selector valve 102 or to connect the inert gas inlet to the second three-way valve 112;

[0049] The second three-way valve 112 is configured to connect the first three-way valve 110 to the first switching valve 103 or to connect the first switching valve 103 to the first flow meter 105.

[0050] In some embodiments, the system further includes a signal acquisition and processing control unit, including temperature and pressure sensors and PID control loops for each temperature control zone, as well as a high-temperature constant temperature zone and a variable temperature control zone; the high-temperature constant temperature zone is specifically defined as H1 to H3, wherein: a pair of multi-select valves 102, a first switching valve 103, a second switching valve 104, and a second three-way valve 112 are located in the H2 high-temperature constant temperature zone, positions S1-7 and both ends of the first-stage low-temperature empty tube dehydration module are located in the H1 high-temperature constant temperature zone, and the Nafion tube dehydration module is located in the H3 high-temperature constant temperature zone;

[0051] The temperature control zones are specifically T1 to T6, all employing PID temperature control with controllable temperature change rates. The first dehydration module 201 is located in the T1 temperature control zone, with a temperature range of -45℃ to 250℃. The second dehydration module 202 is located in the T2 temperature control zone, with a temperature range of -45℃ to 250℃. The collection module 203 is located in the T3 temperature control zone, with a temperature range of -160℃ to 300℃, cooled by a cryogenic compressor. The focusing module 302 is located in the T4 temperature control zone, with a temperature range of -160℃ to 200℃, cooled by a cryogenic compressor. The chromatographic column 401 is located in the T5 temperature control zone, with a temperature range of -5℃ to 300℃. The capillary column purification module 204 is located in the T6 temperature control zone, with a temperature range of 35℃ to 300℃.

[0052] In some embodiments, both the first dehydration module 201 and the second dehydration module 202 use polytetrafluoroethylene hollow tubes with an inner diameter of 2-4 mm and a length of 20-40 cm for cryogenic dehydration, thereby enabling sample collection under positive pressure, normal pressure, and negative pressure; the trapping module 203 is a silanized stainless steel tube with an inner diameter of 2-4 mm and a length of 20-40 cm, filled with a composite packing material of Tenax and carbon molecular sieve, which enriches the target analyte under ultra-low temperature conditions; the capillary column purification module 204 is a 30 m capillary column with a stationary phase coating, used to separate interfering substances and purify the target analyte.

[0053] In some embodiments, the focusing module 302 is a capillary chromatographic column with a stationary phase coating, having an outer diameter of 0.53 mm and a length of 20–40 cm. It is used to focus the target analyte into a very small volume for injection, ensuring sharp chromatographic peaks. The Nafion online dehydration module, which is 2–4 m long, continuously removes moisture from the carrier gas and desorption gas, ensuring that the chromatographic peaks do not drift.

[0054] This utility model embodiment also provides a method for monitoring ozone-depleting substances and hydrofluorocarbons in the atmosphere, using the ozone-depleting substances and hydrofluorocarbons monitoring device as described in any of the above embodiments, and the method includes the following steps:

[0055] S1. Pass the sample gas into the collection pipeline and collect the target substance in the sample gas through the collection module;

[0056] S2. The purification pipeline is switched to the first state. The temperature of the capillary column purification module is set to the fourth given temperature, and the temperature of the collection module is set to the fifth given temperature to decompose interfering substances and some target substances with boiling points below the fifth given temperature. Inert gas is introduced into the purification pipeline and flows into the collection module and the capillary column purification module in sequence, bringing the decomposed interfering substances and some target substances into the capillary column purification module. Chromatographic separation is performed through the capillary column purification module until the interfering substances are eliminated, and the introduction of inert gas is stopped.

[0057] S3. The purification pipeline is switched to the second state. The temperature of the capillary column purification module is set to the sixth given temperature to resolve the partial target analyte. The temperature of the collection module is set to the seventh given temperature. Inert gas is introduced into the purification pipeline to bring the partial target analyte back to the collection module, thus completing the recovery of the partial target analyte. The seventh given temperature is lower than the fifth given temperature.

[0058] S4. The capture switching module is switched to connect the capture module to the analysis pipeline. The temperature of the capture module is set to the eighth given temperature. Carrier gas is introduced into the carrier gas inlet and flows through the capture module to deliver the target object to the focusing analysis module.

[0059] The capillary chromatography column purification module 204 in this embodiment can separate and purify impurities in the sample, including gases such as nitrogen, argon, krypton, and xenon, so that low-boiling-point substances such as NF3 and CF4, which are difficult to detect, can also be accurately qualitatively and quantitatively analyzed.

[0060] The first dehydration module 201, the second dehydration module 202, and the online Nafion tube dehydration module 303 of this utility model embodiment can fully remove a large amount of water from the sample and carrier gas, ensuring the stability of the retention time of each target component in the chromatogram formed by the detection unit, which is beneficial to accurate qualitative and quantitative analysis.

[0061] The trapping module 203 and focusing module 302 in this invention do not require any refrigerant to enter under ultra-low temperature conditions. They can both be cooled to below -160℃ using a compressor, so there is no need to consider the site environment and the economic cost of refrigerant, and they can be put into use as soon as possible.

[0062] The combined action of the refrigerator 404 and heat exchanger 403 in the low-temperature chromatography separation unit of this invention controls the initial column temperature of the chromatography separation unit to be 35°C below room temperature. After injection, the column is refocused to optimize the peak shape, resulting in good separation and improved accuracy and reliability of the analysis.

[0063] In this invention, the Nafion online dehydration device 303 is located between the focusing module 302 and the eight-position switching valve. It cleverly uses the pressure provided by the EPC carrier gas pressure controller to achieve a third dehydration treatment of the carrier gas and the target material, minimizing the interference of moisture removal on the entire analysis.

[0064] The entire system of this invention has high sensitivity and low detection limit, and can effectively detect components with a concentration of some ppt (parts per billion) in ozone-depleting substances (ODS) and hydrofluorocarbons (HFCS).

[0065] Optionally, the sample gas in this invention is a standard gas mixture of 40 ODS and controlled halogenated hydrocarbon gases with a concentration of 100 nmol·mol⁻¹. 1. Ultrapure helium: ≥99.9999%; High-purity nitrogen: ≥99.999%. Standard operating gases: 5, 50, 500 pmol·mol⁻¹ 1 and 1 nmol·mol 1. Prepare by diluting stepwise using a high-precision static diluent.

[0066] In some embodiments, a method for monitoring ozone-depleting substances and hydrofluorocarbons in the atmosphere includes:

[0067] SC1, System standby preparation: Adjust the temperature and gas pressure of each unit; raise the temperature of H1 and H2 areas to 120℃~160℃, raise the temperature of H3 to 40~60℃, adjust the flow rate of the auxiliary nitrogen mass flow meter to 30~60ml / min; lower the temperature of the primary dehydration module and the secondary dehydration module to 0℃~-40℃, lower the temperature of the collection module to -60~-80℃, set the eight-position switching valve and the six-position switching valve to state A, and set all other components to default state.

[0068] SC2, Gas Sample Collection: Gas samples are collected from different Summa canisters through the sampling unit and transported to the concentration and purification unit; the mechanical pump is turned on, and the flow rate is set at 50~100ml / min using a nitrogen mass flow meter until the set volume is reached.

[0069] SC3, freeze dehydration, adsorption and capture: The primary and secondary dehydration modules remove moisture at temperatures of -45℃ to -10℃, while the capture module is set to a temperature of -60℃ to -80℃ to enrich the target analyte.

[0070] SC4, Forward Dry Blow Recovery: Heat the two dehydration modules to 2℃~20℃, set the nitrogen mass flow meter flow rate to 50ml / min~100ml / min, switch the eight-position selector valve to position 7, switch the autosampler selector valve to the nitrogen position, introduce nitrogen to purge the two dehydration modules for 10~45s, and recover the target material in the dehydration modules to the collection module;

[0071] SC5, capture and analyze, cryogenic capillary focusing: adjust the focusing module temperature to -120℃~-130℃, the capture module temperature to 180℃~220℃, switch the eight-position switching valve to state B, and bring the enriched target material into the focusing module for cryogenic focusing through the carrier gas.

[0072] SC6, full volume injection: Control the temperature of the hot nitrogen chamber to 300℃, open the two-way solenoid valve, and use the high temperature nitrogen gas in the hot nitrogen chamber to rapidly heat the focusing module to 180~220℃, so that the target analyte in the focusing module enters the low temperature chromatographic column in the low temperature chromatography separation unit for secondary aggregation.

[0073] SC7, low-temperature chromatographic separation, uses a suitable temperature program and a certain pressure to perform chromatographic separation of the target analytes in the chromatographic column, and the analytes flow into the detector in batches to form a chromatographic mass spectrum for qualitative and quantitative analysis;

[0074] SC8, hot cleaning: the primary and secondary dehydration modules are heated to 180~220℃, the collection module is heated to 200~260℃, the flow rate is set to 80~100mL / min by controlling the nitrogen mass flow meter, the mechanical pump is turned on, and the cleaning is performed for 240s~480s.

[0075] Figure 3 For steps SC1-SC8: the sampling unit collects 1000 ml of 1 nmol·mol⁻¹ The standard gas of 1, after being concentrated and purified, is focused into the low-temperature chromatographic separation and detection unit for processing, resulting in a chromatographic mass spectrum. The spectrum contains 38 target peaks, each marked with a number, and each number below it is explained as representing a target.

[0076] Table 1 shows the low, medium, and high linear relationships, detection limits, and background values ​​of some target compounds obtained from the analysis of a series of standard samples using the atmospheric ozone-depleting substances and hydrofluorocarbons monitoring and analysis system in steps SC1-SC8. In this case, without reverse dry-blowing capillary column purification, the target compounds NF3 and CF4 could not be identified due to interference, and therefore could not be qualitatively or quantitatively analyzed.

[0077] Table 1

[0078]

[0079] In some embodiments, a method for monitoring ozone-depleting substances and hydrofluorocarbons in the atmosphere includes:

[0080] SD1, System standby preparation: Adjust the temperature and gas pressure of each unit; control the temperature of H1 and H2 to 120℃~160℃, control the temperature of H3 to 50℃, adjust the flow rate of the auxiliary nitrogen mass flow meter to 40~60ml / min; control the temperature of the primary dehydration module and the secondary dehydration module to 0℃~-40℃, control the temperature of the collection module to -135~-160℃, the eight-position switching valve and the six-position switching valve are in state A, and all other components are in default state;

[0081] SD2. Collect gas samples: According to the set gas to be collected, switch the eight-position selector valve to sample position 6, open the two-way solenoid valve, start the mechanical pump, and limit the collection flow rate to 50~100ml / min with the nitrogen mass flow meter to collect the set volume.

[0082] SD3, freeze dehydration, adsorption capture: The collected gas sample is dehydrated in a two-stage dehydration module at a temperature of -45℃ to 0℃, and then the dehydrated gas is enriched with the target substance in a capture module at a temperature of -160℃ to -135℃ after passing through a concentration and purification unit.

[0083] SD4, one-time forward dry purge recovery: heat the two dehydration modules to 5℃~10℃, adjust the flow rate of nitrogen mass flow meter to 50ml / min~100ml / min, switch the eight-position selector valve to position 7, switch the autosampler selector valve to the nitrogen position, introduce nitrogen to purge the dehydration modules for 10~30s, and recover the target material retained in the two dehydration modules into the collection module;

[0084] SD5, Helium reverse dry purge purification: Adjust the temperature of the collection module to -120~-100℃, raise the temperature of the capillary column purification module to 35℃~45℃, switch the six-position switching valve to state B, adjust the flow rate of the helium mass flow meter to 4ml / min~10ml / min, open the three-way solenoid valve to introduce helium to purge the silanized three-way collection module for 15s~60s;

[0085] SD6, secondary forward dry purge in situ collection, adjust the temperature of the capillary column purification module to 100℃~150℃, cool the collection module to -160℃~-135℃, adjust the flow rate of the helium mass flow meter to 4ml / min~10ml / min, close the three-way solenoid valve, switch the eight-position selector valve to position 5, and introduce helium to purge the capillary column purification module;

[0086] SD7, capture and analyze, cryogenic capillary focusing: adjust the focusing module temperature to -135℃~-160℃, the capture module temperature to 180℃~250℃, switch the eight-position switching valve to state B, and bring the captured target gas into the focusing module for cryogenic focusing through the carrier gas;

[0087] SD8, full volume injection, control the temperature of the hot nitrogen chamber to 300℃, open the two-way solenoid valve, use the high temperature nitrogen gas in the hot nitrogen chamber to rapidly heat the focusing module to 180~220℃, and introduce the target gas in the focusing module into the low temperature chromatographic column in the low temperature chromatographic analysis unit for secondary aggregation.

[0088] SD9, low-temperature chromatographic separation, uses appropriate carrier gas pressure and temperature program to perform chromatographic separation of target substances in the chromatographic column, and the substances flow into the detector in batches to form chromatographic mass spectra for qualitative and quantitative analysis;

[0089] SD10, hot cleaning, the primary and secondary dehydration modules are heated to 180~210℃, the collection module is heated to 180~250℃, the capillary column purification module is heated to 80℃~150℃, the flow rate is set to 80~160mL / min by controlling the nitrogen mass flow meter, the pump is turned on, and the cleaning is performed for 240s~480s.

[0090] Figure 3 For steps SD1~SD10: The sampling unit collects 1000ml of 1nmol·mol⁻¹ The standard gas of 1, after being concentrated and purified, was introduced into the low-temperature chromatographic separation and detection unit by ultra-low temperature capillary column focusing to obtain a chromatographic mass spectrum. The spectrum contains 40 target peaks, with numbers marked at the top of each peak, and explanations of the target analyte represented by each number below.

[0091] Table 2 shows a comparison of the low, medium, and high correlation coefficients, detection limits, and background values ​​of the target analytes obtained from a series of standard samples analyzed by the ozone-depleting substances and hydrofluorocarbons monitoring and analysis system in steps SD1 to SD10. In steps SD1 to SD10, after reverse dry-blowing capillary column purification and two forward dry-blowing recoveries, NF3 and CF4 were captured and showed significant responses in the spectral path, allowing for qualitative and quantitative analysis.

[0092] Table 2

[0093]

[0094] In the description of this utility model, it should be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "other end", "upper", "side", "top", "inner", "front", "center", "both ends", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0095] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," "screw connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0096] Although embodiments of the present 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 present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for monitoring ozone-depleting substances and hydrofluorocarbons in the atmosphere, characterized in that, include: The target object capture pipeline includes a capture module, which is used to capture the target object in the sample gas; The focusing analysis module is used for focusing and chromatographic separation of target analytes before detection. The analysis pipeline includes an analysis carrier gas inlet and a trapping switching module, wherein the trapping switching module is used to connect the two ends of the trapping module to the analysis carrier gas inlet and the focusing analysis module, respectively. A purification pipeline is provided to remove interfering substances from the target analyte in the trapping module. The purification pipeline includes a capillary column purification module for removing interfering substances from the target analyte. The purification pipeline has a first state and a second state. In the first state, the inert gas passes sequentially through the trapping module and the capillary column purification module. In the second state, the inert gas passes sequentially through the capillary column purification module and the trapping module.

2. The monitoring device for ozone-depleting substances and hydrofluorocarbons in the atmosphere according to claim 1, characterized in that: It also includes a dehydration module, which is located on the target gas collection pipeline and is used to dehydrate the sample gas before it enters the collection module.

3. The monitoring device for ozone-depleting substances and hydrofluorocarbons in the atmosphere according to claim 2, characterized in that: The dehydration module includes a first dehydration module and a second dehydration module; The target collection pipeline also includes an autosampler, a pump, and a first flow meter. The autosampler is used to connect to the Summa tank. The pump is located at one end near the outlet of the target collection pipeline. The autosampler is connected to the pump in sequence through the first dehydration module, the second dehydration module, the collection module, and the first flow meter. The focusing analysis module includes a focusing module, a chromatographic separation module, and a detection unit connected in sequence. The focusing module is used to focus the target analyte and input the target analyte into the chromatographic separation module. The chromatographic separation module is used to perform chromatographic separation on the target analyte and then input it into the detection unit. The inlet of the focusing module is connected to the multi-stage analytical pipeline.

4. The ozone-depleting substances and hydrofluorocarbons monitoring device in the atmosphere according to claim 3, characterized in that: It also includes a one-to-many selector valve, a first switching valve, and a second switching valve; The one-to-many selector valve has a fixed interface and a plurality of selectable interfaces, and the one-to-many selector valve is configured to connect one of the fixed interfaces to one of the selectable interfaces. The autosampler is connected to the selection interface S7 of the one-to-many selector valve via the first dehydration module. The fixed interface is connected to the interface P1 of the first switching valve. The interface P2 of the first switching valve is connected to the interface P5 of the second switching valve. The two ends of the trapping module are connected to the interfaces P3 and P6 of the first switching valve, respectively. The interface P4 of the first switching valve is connected to the focusing module. The interface P5 of the first switching valve is connected to the desorption carrier gas inlet. The interface P7 of the first switching valve is connected to the pump via the first flow meter. The interface P8 of the first switching valve is connected to the interface P2 of the second switching valve. The two ends of the second dehydration module are connected to the interfaces P3 and P4 of the second switching valve, respectively. The two ends of the capillary column purification module are connected to the interfaces P6 and P1 of the second switching valve, respectively. The first switching valve has an A state and a B state. When the first switching valve is in the A state, only its interfaces P1 and P8, P2 and P3, P4 and P5, and P6 and P7 are connected. When the first switching valve is in the B state, only its interfaces P1 and P2, P3 and P4, P5 and P6, and P7 and P8 are connected. The second switching valve has an A state and a B state. When the second switching valve is in the A state, only its interfaces P1 and P6, P2 and P3, and P4 and P5 are connected. When the second switching valve is in the B state, only its interfaces P1 and P2, P4 and P5, and P5 and P6 are connected.

5. A monitoring device for ozone-depleting substances and hydrofluorocarbons in the atmosphere according to claim 4, characterized in that: The purification pipeline includes an inert gas inlet, a first three-way valve, and a second three-way valve; One end of the first three-way valve is connected to one end of the second three-way valve. The other two ends of the first three-way valve are respectively connected to the inert gas inlet and the selection interface S5 of the one-to-many selector valve. The other two ends of the second three-way valve are respectively connected to the interface P7 of the first switching valve and the first flow meter. The first three-way valve is configured to connect the inert gas inlet to the one-to-many selector valve or to connect the inert gas inlet to the second three-way valve; The second three-way valve is configured to connect the first three-way valve to the first switching valve or to connect the first switching valve to the first flow meter.

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