A detection system for ODS

Abstract

The utility model discloses a detection system for ODS, including the sampling device, pre -concentration device and GCMS detection device who connects gradually, first multi -way valve links with sampling port, first carrier gas port, CO2 adsorption pipe's import, first cold trap's first mouth, first cold trap's second mouth, second carrier gas port and second multi -way valve respectively, second multi -way valve links with sampling pump subassembly, CO2 adsorption pipe's export, second cold trap's first mouth, second cold trap's second mouth, first multi -way valve and GCMS detection device respectively, first cold trap is used for the capture of all ODS in sample gas to with boiling point less than or equal to CO2 boiling point's ODS carries out first analysis, and the residual ODS carries out second analysis, CO2 adsorption pipe is used for the adsorption of CO2 in the ODS that first cold trap first analysis has come out, second cold trap is used for the focusing of ODS that first cold trap twice analysis has come out. The utility model has the advantages of high test precision and high test accuracy.

Description

Technical Field

[0001] This utility model relates to the field of environmental monitoring technology, and in particular to a detection system for ODS. Background Technology

[0002] In the detection of ODS (Ozone-Depleting Substances) in the atmosphere, because the concentration of ODS substances ranges from ppb (parts per billion) to ppt (parts per trillion), samples need to be concentrated before being injected into GCMS (Gas Chromatography-Mass Spectrometry) for content analysis. The number of ODS components to be detected is large (up to 50 or more), with boiling points spanning a wide temperature range from -128℃ to 230℃. How to capture and analyze all the analytes while ensuring analytical accuracy is a significant challenge in the industry. In particular, low-boiling-point substances CF4 and NF3 are easily masked by the CO2 peak in the GCMS response results, making them unidentifiable. During the capture / desorption of CF4 and NF3, CO2 (which accounts for about 0.03% in the atmosphere, a much larger order of magnitude than the analyte, and has a boiling point of -78℃, while CF4 and NF3 have a boiling point of about -128℃) is also captured / desorbed. Therefore, efficient removal of CO2 is required.

[0003] Currently, CO2 adsorption tubes are typically placed before dehydration tubes to remove CO2 from samples. However, when dealing with trace ODS detection, this approach can lead to the loss of high-boiling-point substances. Furthermore, the high-boiling-point substances adsorbed by the CO2 adsorbent are subsequently released slowly and randomly, resulting in decreased accuracy in subsequent tests. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a detection system for ODS with high testing precision and accuracy.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A detection system for ODS includes a sample injection device, a pre-concentration device, and a GCMS detection device connected in sequence. The pre-concentration device includes a sample inlet, a first carrier gas inlet, a sample injection pump assembly, a CO2 adsorption tube, a first multi-way valve, a second multi-way valve, a first cold trap, a second carrier gas inlet, and a second cold trap. The sample injection device is connected to the sample inlet. The first multi-way valve is connected to the sample inlet, the first carrier gas inlet, the inlet of the CO2 adsorption tube, the first port of the first cold trap, the second port of the first cold trap, the second carrier gas inlet, and the second multi-way valve. The second multi-way valve is connected to the sample injection pump assembly, the outlet of the CO2 adsorption tube, the first port of the second cold trap, the second port of the second cold trap, the first multi-way valve, and the GCMS detection device. The first cold trap is used to capture all ODS in the sample gas, perform a first desorption of ODS with a boiling point less than or equal to the boiling point of CO2, and perform a second desorption of the remaining ODS. The CO2 adsorption tube is used to adsorb CO2 in the ODS desorbed from the first cold trap in the first desorption. The second cold trap is used to focus the ODS desorbed from the first cold trap in the two desorptions.

[0006] As a further improvement to the above technical solution: The first multi-way valve is a two-position six-way valve. The first multi-way valve includes port A, port B, port C, port D, port E, and port F. Port A is connected to the sample inlet and the first carrier gas port, respectively. Port B is connected to the inlet of the CO2 adsorption tube. Port C is connected to the second port of the first cold trap. Port D is connected to the second carrier gas port. Port E is connected to the second multi-way valve. Port F is connected to the first port of the first cold trap. When the first multi-way valve is switched to position one, port A is connected to port B, port C is connected to port D, and port E is connected to port F. When the first multi-way valve is switched to position two, port B is connected to port C, port D is connected to port E, and port F is connected to port A. The second multi-way valve is a two-position six-way valve, which includes ports a, b, c, d, e, and f. Port a is connected to the first port of the second cold trap, port b is connected to the outlet of the CO2 adsorption tube, port c is connected to the sample injection pump assembly, port d is connected to the second port of the second cold trap, port e is connected to port E of the first multi-way valve, and port f is connected to the GCMS detection device. When the second multi-way valve is switched to position one, ports a and b, c and d, and e and f are connected. When the second multi-way valve is switched to position two, ports b and c, d and e, and f are connected.

[0007] The pre-concentration device further includes a first manifold, which is connected to port A of a first multi-way valve. The sample inlet and the first carrier gas port are respectively connected to the first manifold. An inlet valve is provided between the sample inlet and the first manifold, and a sample carrier gas valve is provided between the first carrier gas port and the first manifold.

[0008] The pre-concentration device also includes an internal standard port, which is connected to a first manifold, and an internal standard valve is provided between the internal standard port and the first manifold.

[0009] The injection device includes a switching mechanism, a purge port, and multiple sampling containers. The switching mechanism is used to switch the purge port and connect different sampling containers to the injection port. The pre-concentration device further includes an exhaust port, a second manifold, and a cleaning valve. The second manifold is connected to port c of the second multi-way valve. The exhaust port and the sample pump assembly are respectively connected to the second manifold. An exhaust valve is provided between the exhaust port and the second manifold. The first manifold is connected to the second manifold through the cleaning valve.

[0010] A water removal device is provided between the sample injection device and the sample inlet.

[0011] Compared with the prior art, the advantages of this utility model are: 1. This utility model's ODS detection system uses a first cold trap to capture all ODS in the sample gas. Then, through two separate analyses, ODS with different boiling points are separated. CO2 and ODS with boiling points less than or equal to CO2 are adsorbed by a CO2 adsorption tube to remove CO2 before entering the second cold trap for focusing. ODS with boiling points higher than CO2 bypass the CO2 adsorption tube and directly enter the second cold trap for focusing. This effectively removes CO2 while minimizing the loss of high-boiling-point ODS and preventing the CO2 adsorbent from adsorbing high-boiling-point substances, which could affect subsequent tests. The system boasts high accuracy. All the analyzed ODS enters the second cold trap for focusing, which means that the analyzed ODS is concentrated again under low temperature conditions, reducing peak broadening and improving detection sensitivity. Moreover, the second cold trap injects all the ODS into the GCMS detection device at once, which is faster and more accurate than the technical solution of multiple injections and combined analysis. By setting two carrier gas ports, when the first carrier gas performs the first analysis on the first cold trap, the second carrier gas can continuously supply gas to the second cold trap and the GCMS detection device, preventing gas interruption in the GCMS detection device and the second cold trap, which would lead to the entry of external impurities and cause contamination, thus improving the test accuracy.

[0012] 2. The detection system for ODS of this utility model has two two-position six-way valves, which are simple and compact in structure. By simply switching the first or second position, the connection between different channels can be switched, realizing the conversion of different processes such as sample collection, first analysis, second analysis and injection. The structure is reasonable and the control is reliable.

[0013] 3. In the detection system for ODS of this utility model, since both the sample gas and the first carrier gas enter from the A port of the first multi-way valve, the flow is combined by setting the first manifold, which facilitates the management and distribution of airflow and reduces the connection points and leakage risks.

[0014] 4. The detection system for ODS of this utility model can perform purging simultaneously during the second analysis and injection processes. The purging gas enters from the purging port to purge each pipeline and component, preparing for the next sample injection. This allows the detection system of this embodiment to perform continuous detection with high work efficiency. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the sample introduction and collection process of the ODS detection system of this utility model.

[0016] Figure 2 This is a schematic diagram of the first analysis process of the ODS detection system of this utility model.

[0017] Figure 3 This is a schematic diagram of the second analytical process of the ODS detection system of this utility model.

[0018] Figure 4 This is a schematic diagram of the injection process of the ODS detection system of this utility model.

[0019] The labels in the diagram represent: 1. Sample introduction device; 11. Sampling vessel; 12. Purge port; 2. Dehydration device; 3. Pre-concentration device; 31. Sample inlet; 32. Internal standard port; 33. First carrier gas port; 34. Exhaust port; 35. Sample pump assembly; 36. Sample valve; 37. Internal standard valve; 38. Sample carrier gas valve; 39. Exhaust valve; 310. Flow controller; 311. First manifold; 312. Second manifold; 313. Cleaning valve; 314. CO2 adsorption tube; 315. First multi-way valve; 316. Second multi-way valve; 317. First cold trap; 318. Second carrier gas port; 319. Second cold trap; 4. GCMS detection device. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] In the description of this utility model, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying 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.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] In this utility model, unless otherwise explicitly specified and limited, the terms "assembly," "connection," "joining," and "fixing" 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. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0024] Example 1: like Figures 1 to 4As shown, the ODS detection system of this embodiment includes a sample injection device 1, a pre-concentration device 3, and a GCMS detection device 4 connected in sequence. The pre-concentration device 3 includes an inlet 31, a first carrier gas port 33, a sample injection pump assembly 35, a CO2 adsorption tube 314, a first multi-way valve 315, a second multi-way valve 316, a first cold trap 317, a second carrier gas port 318, and a second cold trap 319. The sample injection device 1 is connected to the inlet 31. The first multi-way valve 315 is connected to the inlet 31, the first carrier gas port 33, the inlet of the CO2 adsorption tube 314, the first port of the first cold trap 317, the second port of the first cold trap 317, the second carrier gas port 318, and the second cold trap 319. A multi-way valve 316 is connected to the sample pump assembly 35, the outlet of the CO2 adsorption tube 314, the first port of the second cold trap 319, the second port of the second cold trap 319, the first multi-way valve 315, and the GCMS detection device 4. The first cold trap 317 is used to capture all ODS in the sample gas, and to perform a first analysis on ODS with a boiling point less than or equal to the boiling point of CO2, and a second analysis on the remaining ODS. The CO2 adsorption tube 314 is used to adsorb CO2 in the ODS analyzed by the first cold trap 317 in the first analysis. The second cold trap 319 is used to focus the ODS analyzed by the first cold trap 317 in the two analyses.

[0025] The ODS detection system of this embodiment, when in operation, such as Figure 1 As shown in the red route, the first cold trap 317 is at a first temperature (specifically -150℃ to -170℃). The sample gas in the injection device 1 passes sequentially through the injection port 31, the first multi-way valve 315, the first cold trap 317, the CO2 adsorption tube 314, and the second multi-way valve 316, and is finally drawn by the injection pump assembly 35. The first cold trap 317 captures all ODS in the sample gas, completing the injection and capture process. Figure 2 As shown in the red route, the second cold trap 319 is at the second temperature (specifically -185℃ to -195℃), and the first cold trap 317 is heated to the third temperature (specifically -60℃ to -45℃). This allows the ODS with boiling points less than or equal to the boiling point of CO2 in the first cold trap 317 to be desorbed. The first carrier gas sequentially passes through the first carrier gas port 33, the first multi-way valve 315, the first cold trap 317, the CO2 adsorption tube 314, the second multi-way valve 316, the second cold trap 319, and the sample injection pump assembly 35. The second cold trap 319 focuses the ODS desorbed from the first cold trap 317 after adsorption by the CO2 adsorption tube 314, completing the first desorption. Figure 3As shown in the green route, the first cold trap 317 is heated to a fourth temperature (specifically 210℃ to 240℃) to extract the remaining ODS in the first cold trap 317. The second carrier gas sequentially passes through the second carrier gas port 318, the first multi-way valve 315, the first cold trap 317, the first multi-way valve 315, the second multi-way valve 316, the second cold trap 319, and the second multi-way valve 316, and finally enters the GCMS detection device 4. The second cold trap 319 focuses the remaining ODS in the first cold trap 317, completing the second extraction. Figure 4 As shown in the green route, the second cold trap 319 is heated to the fifth temperature (specifically 75°C to 100°C) to extract all the ODS in the second cold trap 319. The second carrier gas passes sequentially through the second carrier gas port 318, the first multi-way valve 315, the second multi-way valve 316, the second cold trap 319, and the second multi-way valve 316. The second carrier gas carries the ODS extracted from the second cold trap 319 and injects it into the GCMS detection device 4 for detection.

[0026] The ODS detection system in this embodiment captures all ODS in the sample gas through the first cold trap 317, and then separates ODS with different boiling points through two analysis steps. CO2 and ODS with boiling points less than or equal to CO2 are adsorbed by the CO2 adsorption tube 314 to remove CO2, and then enter the second cold trap 319 for focusing. ODS with boiling points higher than CO2 bypass the CO2 adsorption tube 314 and directly enter the second cold trap 319 for focusing. This effectively removes CO2 while reducing the loss of high-boiling-point ODS and prevents the CO2 adsorbent from adsorbing high-boiling-point substances, which would affect subsequent tests, resulting in high test accuracy. All ODS are focused into the second cold trap 319, which concentrates the analyzed ODS a second time under low temperature conditions, reducing peak broadening and improving detection sensitivity. The second cold trap 319 injects all ODS into the GCMS detection device 4 at once, which is faster and more accurate than the technique of multiple injections and combined analysis. By setting two carrier gas ports, when the first carrier gas performs the first analysis on the first cold trap 317, the second carrier gas can continuously supply gas to the second cold trap 319 and the GCMS detection device 4, preventing gas interruption in the GCMS detection device 4 and the second cold trap 319, which would lead to the entry of external impurities and cause contamination, thus improving the test accuracy.

[0027] Furthermore, in this embodiment, the first multi-way valve 315 is a two-position six-way valve. The first multi-way valve 315 includes port A, port B, port C, port D, port E, and port F. Port A is connected to the sample inlet 31 and the first carrier gas port 33, respectively. Port B is connected to the inlet of the CO2 adsorption tube 314. Port C is connected to the second port of the first cold trap 317. Port D is connected to the second carrier gas port 318. Port E is connected to the second multi-way valve 316. Port F is connected to the first port of the first cold trap 317. When the first multi-way valve 315 is switched to position one, port A is connected to port B, port C is connected to port D, and port E is connected to port F. When the first multi-way valve 315 is switched to position two, port B is connected to port C, port D is connected to port E, and port F is connected to port A. The second multi-way valve 316 is a two-position six-way valve. The second multi-way valve 316 includes port a, port b, port c, port d, port e, and port f. Port a is connected to the first port of the second cold trap 319, port b is connected to the outlet of the CO2 adsorption tube 314, port c is connected to the sample injection pump assembly 35, port d is connected to the second port of the second cold trap 319, port e is connected to port E of the first multi-way valve 315, and port f is connected to the GCMS detection device 4. When the second multi-way valve 316 is switched to position one, port a is connected to port b, port c is connected to port d, and port e is connected to port f. When the second multi-way valve 316 is switched to position two, port b is connected to port c, port d is connected to port e, and port f is connected to port a. Both the first multi-way valve 315 and the second multi-way valve 316 are two-position six-way valves with a simple and compact structure. By simply switching between position one and position two, the connection between different channels can be switched, realizing the conversion between different processes such as sample collection, first analysis, second analysis and injection. The structure is reasonable and the control is reliable.

[0028] Furthermore, in this embodiment, the pre-concentration device 3 also includes a first manifold 311, which is connected to port A of the first multi-way valve 315. The sample inlet 31 and the first carrier gas inlet 33 are respectively connected to the first manifold 311. A sample inlet valve 36 is provided between the sample inlet 31 and the first manifold 311, and a sample carrier gas valve 38 is provided between the first carrier gas inlet 33 and the first manifold 311. Since both the sample gas and the first carrier gas enter from port A of the first multi-way valve 315, the first manifold 311 facilitates the management and distribution of airflow and reduces connection points and leakage risks.

[0029] Furthermore, in this embodiment, the pre-concentration device 3 also includes an internal standard port 32, which is connected to the first manifold 311. An internal standard valve 37 is provided between the internal standard port 32 and the first manifold 311. The internal standard port 32 can be used for internal standard injection to calibrate the instrument and improve detection accuracy.

[0030] Furthermore, in this embodiment, the sample injection device 1 includes a switching mechanism, a purge port 12, and multiple sampling containers 11. The switching mechanism is used to switch the purge port 12 and different sampling containers 11 to communicate with the sample injection port 31. The pre-concentration device 3 also includes an exhaust port 34, a second manifold 312, and a cleaning valve 313. The second manifold 312 is connected to port c of the second multi-way valve 316. The exhaust port 34 and the sample pump assembly 35 are respectively connected to the second manifold 312. An exhaust valve 39 is provided between the exhaust port 34 and the second manifold 312. The first manifold 311 is connected to the second manifold 312 through the cleaning valve 313. By switching via a switching mechanism, the purge port 12 can be connected to the sample inlet 31 to introduce purge gas; or the sampling tank 11 can be connected to the sample inlet 31 to introduce sample gas. The structure is simple and reliable. During the second analysis and injection processes, purging can be performed simultaneously. The purge gas enters from the purge port 12 to purge each pipeline and component, preparing for the next sample injection. This allows the detection system of this embodiment to perform continuous detection with high efficiency.

[0031] Preferably, the exhaust port 34 is connected to a waste gas collection device, which can collect and treat the discharged waste gas.

[0032] Furthermore, in this embodiment, a water removal device 2 is provided between the sample injection device 1 and the sample inlet 31. The water removal device 2 removes moisture from the sample gas, reducing moisture interference and improving test accuracy. Preferably, in this embodiment, the water removal device 2 is a Nafion tube, which is simple and reliable in structure.

[0033] Furthermore, in this embodiment, the sample injection pump assembly 35 includes a sample injection pump and a flow controller 310, with the flow controller 310 connected between the sample injection pump and the second multi-way valve 316. The flow controller 310 can control the sample gas flow rate during the trapping process and the desorption flow rate of ODS in the first cold trap 317 during the first desorption process, preventing sample or ODS loss due to excessive flow rate.

[0034] Example 2: like Figures 1 to 4 As shown, the detection method for the ODS detection system based on Embodiment 1 in this embodiment includes the following steps: like Figure 1 As shown in the red route, step S1: Sample introduction and collection: the first cold trap 317 is at the first temperature, and the first cold trap 317 collects all the ODS in the sample gas; like Figure 2As shown in the red route, step S2: First analysis: The second cold trap 319 is at the second temperature, and the first cold trap 317 is heated to the third temperature. The ODS with a boiling point less than or equal to the boiling point of CO2 in the first cold trap 317 is analyzed and CO2 is adsorbed by the CO2 adsorption tube 314. The second cold trap 319 focuses the ODS analyzed by the first cold trap 317 after adsorption by the CO2 adsorption tube 314. like Figure 3 As shown in the green route, step S3: Second analysis: The first cold trap 317 is heated to the fourth temperature to analyze the remaining ODS in the first cold trap 317, and the second cold trap 319 focuses the remaining ODS in the first cold trap 317. like Figure 4 As shown in the green route, step S4: Injection: The second cold trap 319 is heated to the fifth temperature, all ODS in the second cold trap 319 are extracted and injected into the GCMS detection device 4.

[0035] The detection method in this embodiment captures all ODS in the sample gas through the first cold trap 317, and then separates ODS with different boiling points through two analysis steps. CO2 and ODS with boiling points less than or equal to CO2 are adsorbed by the CO2 adsorption tube 314 to remove CO2, and then enter the second cold trap 319 for focusing. ODS with boiling points higher than CO2 do not pass through the CO2 adsorption tube 314 and directly enter the second cold trap 319 for focusing. This effectively removes CO2 while reducing the loss of high-boiling-point ODS and prevents the CO2 adsorbent from adsorbing high-boiling-point substances, which would affect subsequent tests, resulting in high test accuracy. The ODS from both analysis steps are focused in the second cold trap 319, which means that the analyzed ODS are concentrated again under low temperature conditions, reducing peak broadening and improving detection sensitivity. Furthermore, the second cold trap 319 injects all ODS into the GCMS detection device 4 at once. Compared with the technical solution of multiple injections and combined analysis, the analysis speed is faster and the results are more accurate.

[0036] Furthermore, in this embodiment, as Figure 1As shown in the red route, in step S1, the sample collection process is as follows: the first multi-way valve 315 is in position two, the second multi-way valve 316 is in position two, the first cold trap 317 is at the first temperature, and the sample gas in the sample injection device 1 passes sequentially through the sample inlet 31, the first multi-way valve 315 (specifically, port A and port F), the first cold trap 317 (specifically, the first port and the second port of the first cold trap 317), the first multi-way valve 315 (specifically, port C and port B), the CO2 adsorption tube 314 (specifically, the inlet and outlet of the CO2 adsorption tube 314), and the second multi-way valve 316 (specifically, port b and port c). Finally, it is extracted by the sample injection pump assembly 35, and the first cold trap 317 collects all the ODS in the sample gas. like Figure 2 As shown in the red route, in step S2, the first analysis process is as follows: the first multi-way valve 315 is in position two, the second multi-way valve 316 is switched to position one, the second cold trap 319 is at the second temperature, and the first cold trap 317 is heated to the third temperature to extract the ODS in the first cold trap 317 with a boiling point less than or equal to the boiling point of CO2. The first carrier gas passes sequentially through the first carrier gas port 33, the first multi-way valve 315 (specifically port A and port F), and the first cold trap 317 (specifically the first port and the second port of the first cold trap 317). The system includes a first multi-way valve 315 (specifically ports C and B), a CO2 adsorption tube 314 (specifically the inlet and outlet of the CO2 adsorption tube 314), a second multi-way valve 316 (specifically ports b and a), a second cold trap 319 (specifically the first and second ports of the second cold trap 319), a second multi-way valve 316 (specifically ports d and c), and a sample injection pump assembly 35. The second cold trap 319 focuses the ODS desorbed from the first cold trap 317 after adsorption by the CO2 adsorption tube 314. like Figure 3 As shown in the green route, in step S3, the second analysis process is as follows: the first multi-way valve 315 is switched to position one, the second multi-way valve 316 is switched to position two, the first cold trap 317 is heated to the fourth temperature, and the remaining ODS in the first cold trap 317 is analyzed. The second carrier gas passes sequentially through the second carrier gas port 318, the first multi-way valve 315 (specifically port D and port C), the first cold trap 317 (specifically the second port and the first port of the first cold trap 317), the first multi-way valve 315 (specifically port F and port E), the second multi-way valve 316 (specifically port e and port d), the second cold trap 319 (specifically the second port and the first port of the second cold trap 319), and the second multi-way valve 316 (specifically port a and port f). Finally, it is introduced into the GCMS detection device 4, and the second cold trap 319 focuses the remaining ODS in the first cold trap 317. like Figure 4As shown in the green route, in step S4, the injection process is as follows: the first multi-way valve 315 is switched to position two, the second multi-way valve 316 is in position two, the second cold trap 319 is heated to the fifth temperature, and all ODS in the second cold trap 319 are extracted. The second carrier gas passes sequentially through the second carrier gas port 318, the first multi-way valve 315 (specifically ports D and E), the second multi-way valve 316 (specifically ports e and d), the second cold trap 319 (specifically the second port and the first port of the second cold trap 319), and the second multi-way valve 316 (specifically ports a and f). The second carrier gas carries the ODS extracted from the second cold trap 319 and injects it into the GCMS detection device 4 for detection. By switching the first multi-way valve 315 and the second multi-way valve 316 to position one or two, the connection between different channels can be switched, realizing the conversion between different procedures such as sample collection, first analysis, second analysis, and injection. The control process is reasonable and reliable.

[0037] Furthermore, in this embodiment, as Figure 1 As shown in the green route, in step S1, the second carrier gas also passes sequentially through the second carrier gas port 318, the first multi-way valve 315 (specifically ports D and E), the second multi-way valve 316 (specifically ports e and d), the second cold trap 319 (specifically the second port and the first port of the second cold trap 319), and the second multi-way valve 316 (specifically ports a and f), and finally enters the GCMS detection device 4; like Figure 2 As shown in the green route, in step S2, the second carrier gas sequentially passes through the second carrier gas port 318, the first multi-way valve 315 (specifically ports D and E), and the second multi-way valve 316 (specifically ports e and f), and finally enters the GCMS detection device 4. Since the GCMS detection device 4 requires continuous gas flow to prevent impurities from entering, and during sample collection and the first analysis, the sample gas and the first carrier gas are not introduced into the GCMS detection device 4. Therefore, in step S1, by continuously introducing the second carrier gas into the GCMS detection device 4 and the second cold trap 319, gas interruption in the GCMS detection device 4 and the second cold trap 319 is prevented, thus preventing contamination; in step S2, by continuously introducing the second carrier gas into the GCMS detection device 4, gas interruption in the GCMS detection device 4 is prevented, thus preventing contamination, resulting in higher test accuracy.

[0038] Furthermore, in this embodiment, as Figure 3 As shown in the red route, step S3 also includes the purge gas passing sequentially through the purge port 12, the sample inlet 31, the first manifold 311, the cleaning valve 313 and the second manifold 312, and finally being discharged through the exhaust port 34. like Figure 4As shown in the red route, step S4 also includes the purge gas passing sequentially through the purge port 12, the sample inlet 31, the first manifold 311, the first multi-way valve 315 (specifically, ports A and F), the first cold trap 317 (specifically, the first port and the second port of the first cold trap 317), the first multi-way valve 315 (specifically, ports C and B), the CO2 adsorption tube 314 (specifically, the inlet and outlet of the CO2 adsorption tube 314), the second multi-way valve 316 (specifically, ports b and c), and the second manifold 312, and finally being discharged through the exhaust port 34.

[0039] In step S3, the purge gas enters through the purge port 12. Due to the large gas resistance inside the CO2 adsorption tube 314 filled with adsorbent, the cleaning valve 313 opens, and the gas flows along the path of least resistance without passing through the tube. The CO2 adsorbent inside the tube will not adsorb the high-boiling-point target substances in the residual sample in the front end of the tube. In step S4, the cleaning valve 313 closes, and the purge gas cleans and purges the first cold trap 317 and the CO2 adsorption tube 314, releasing the trace amounts of ODS remaining in the first cold trap 317 and the CO2 adsorption tube 314, preparing for the next sample injection. This allows for continuous detection and high working efficiency.

[0040] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to preferred embodiments, it is not intended to limit the present utility model. Any person skilled in the art can make many possible variations and modifications to the technical solution of the present utility model using the methods and techniques disclosed above, or modify it into equivalent embodiments with equivalent changes, without departing from the spirit and technical solution of the present utility model. Therefore, any simple modifications, equivalent substitutions, equivalent changes and modifications made to the above embodiments based on the technical essence of the present utility model without departing from the content of the technical solution of the present utility model shall still fall within the protection scope of the technical solution of the present utility model.

Claims

1. A detection system for ODS, characterized by: The device includes a sample injection device (1), a pre-concentration device (3), and a GCMS detection device (4) connected in sequence. The pre-concentration device (3) includes an inlet (31), a first carrier gas port (33), an injection pump assembly (35), a CO2 adsorption tube (314), a first multi-way valve (315), a second multi-way valve (316), a first cold trap (317), a second carrier gas port (318), and a second cold trap (319). The sample injection device (1) is connected to the inlet (31). The first multi-way valve (315) is connected to the inlet (31), the first carrier gas port (33), the inlet of the CO2 adsorption tube (314), the first port of the first cold trap (317), the second port of the first cold trap (317), the second carrier gas port (318), and the second multi-way valve (319). The first cold trap (317) is connected to the sample pump assembly (35), the outlet of the CO2 adsorption tube (314), the first port of the second cold trap (319), the second port of the second cold trap (319), the first multi-way valve (315), and the GCMS detection device (4). The first cold trap (317) is used to capture all ODS in the sample gas, and to perform a first analysis on ODS with a boiling point less than or equal to the boiling point of CO2, and a second analysis on the remaining ODS. The CO2 adsorption tube (314) is used to adsorb CO2 in the ODS analyzed by the first cold trap (317) for the first time. The second cold trap (319) is used to focus the ODS analyzed by the first cold trap (317) for the two times.

2. The detection system for ODS according to claim 1, characterized in that: The first multi-way valve (315) is a two-position six-way valve. The first multi-way valve (315) includes port A, port B, port C, port D, port E and port F. Port A is connected to the sample inlet (31) and the first carrier gas port (33) respectively. Port B is connected to the inlet of the CO2 adsorption tube (314). Port C is connected to the second port of the first cold trap (317). Port D is connected to the second carrier gas port (318). Port E is connected to the second multi-way valve (316). Port F is connected to the first port of the first cold trap (317). When the first multi-way valve (315) is switched to position 1, port A is connected to port B, port C is connected to port D, and port E is connected to port F. When the first multi-way valve (315) is switched to position 2, port B is connected to port C, port D is connected to port E, and port F is connected to port A. The second multi-way valve (316) is a two-position six-way valve. The second multi-way valve (316) includes port a, port b, port c, port d, port e and port f. Port a is connected to the first port of the second cold trap (319), port b is connected to the outlet of the CO2 adsorption tube (314), port c is connected to the sample pump assembly (35), port d is connected to the second port of the second cold trap (319), port e is connected to the E port of the first multi-way valve (315), and port f is connected to the GCMS detection device (4). When the second multi-way valve (316) is switched to position one, port a is connected to port b, port c is connected to port d, and port e is connected to port f. When the second multi-way valve (316) is switched to position two, port b is connected to port c, port d is connected to port e, and port f is connected to port a.

3. The detection system for ODS of claim 2, wherein: The pre-concentration device (3) further includes a first manifold (311), which is connected to port A of the first multi-way valve (315). The sample inlet (31) and the first carrier gas inlet (33) are respectively connected to the first manifold (311). A sample inlet valve (36) is provided between the sample inlet (31) and the first manifold (311), and a sample carrier gas valve (38) is provided between the first carrier gas inlet (33) and the first manifold (311).

4. The detection system for ODS according to claim 3, characterized in that: The pre-concentration device (3) also includes an inner standard port (32), which is connected to the first manifold (311), and an inner standard valve (37) is provided between the inner standard port (32) and the first manifold (311).

5. The detection system for ODS of claim 3, wherein: The injection device (1) includes a switching mechanism, a purge port (12) and multiple sampling containers (11). The switching mechanism is used to switch the purge port (12) and different sampling containers (11) to communicate with the injection port (31). The pre-concentration device (3) further includes an exhaust port (34), a second manifold (312), and a cleaning valve (313). The second manifold (312) is connected to port c of the second multi-way valve (316). The exhaust port (34) and the sample pump assembly (35) are respectively connected to the second manifold (312). An exhaust valve (39) is provided between the exhaust port (34) and the second manifold (312). The first manifold (311) is connected to the second manifold (312) through the cleaning valve (313).

6. The detection system for ODS of claim 1, wherein: A water removal device (2) is provided between the sample injection device (1) and the sample inlet (31).

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