A sample pre-concentration and separation system and method for measuring trace substances in environmental water

Abstract

The present invention discloses a sample pre-concentration and separation system and method for measuring trace substances in environmental water bodies, which belongs to the field of detection of trace gases dissolved in water bodies, and aims to solve the technical problem of low separation and sensitivity of single equipment in the prior art. It includes a gas injection module, a sample quantification module, a water sample pretreatment module, a capture and analysis module, and a separation and detection module. The present invention utilizes two sets of pre-column and analytical column systems to achieve the cascade separation of components with different properties. Substances with different separation activities can be effectively separated under flow switching, effectively avoiding confusion caused by similar functional groups, eliminating interference, and improving the separation and measurement sensitivity of the target object; at the same time, two sets of detectors are used to meet the needs of different sensitivity detection.

Description

Technical Field

[0001] The present invention relates to the field of detection of trace gases dissolved in water, and in particular to a sample pre-concentration and separation system and method for measuring trace substances in environmental water. Background Art

[0002] With the entry into force of the Montreal Protocol, the production and use of major chlorofluorocarbons (CFCs) and other chlorine- and bromine-containing compounds have been gradually banned and phased out. Current alternatives include hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs). As long-term replacements for CFCs and HCFCs, HFCs continue to experience a rapid increase in atmospheric abundance and contribute to increased radiative forcing. Perfluorocarbons (PFCs) and sulfur hexafluoride (SF6), with atmospheric lifetimes of up to thousands of years, are three of the six major greenhouse gases targeted by the Kyoto Protocol, along with HFCs. These substances are also released into the aquatic environment through the atmospheric and water cycles. Therefore, high-quality, high-resolution detection of these substances is crucial.

[0003] However, the current challenge is that these substances have varying physical properties and solubility in water, with concentrations ranging from fmol / L (10-15) to μmol / L (10-6). This often requires different equipment to enrich, separate, and detect a range of substances. Even if a single device can separate multiple target substances, its resolution and sensitivity are often low, making it inadequate for monitoring.

[0004] Therefore, a system is urgently needed to achieve the enrichment and separation of the above-mentioned trace halogenated hydrocarbons, hydrocarbons and sulfides. Summary of the Invention

[0005] The purpose of the present invention is to provide a sample pre-concentration and separation system and method for measuring trace substances in environmental water, so as to solve the technical problem of low separation and sensitivity of single equipment in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solutions:

[0007] The present invention provides a sample pre-concentration and separation system for measuring trace substances in environmental water, comprising:

[0008] A gas injection module, which is used to provide standard gas, purge gas and sample source to the system;

[0009] A sample quantification module, the gas sampling module is connected to the sample quantification module, and the sample quantification module includes a plurality of quantitative loops and a plurality of multi-way valves connected in series for controlling and adjusting the sample amount;

[0010] A water sample pretreatment module, comprising a purge pipe, a first drying and acid removal pipe, a second drying and acid removal pipe, and a plurality of multi-way valves;

[0011] A capture and analysis module, wherein the gas sampling module and the water pretreatment module are respectively connected to the capture and analysis module, and the capture and analysis module includes a front capture tube, a rear capture tube and a plurality of multi-way valves for achieving the enrichment, cryofocusing and transfer of the target;

[0012] The separation and detection module includes a pre-column 1, a pre-column 2, an analytical column 1, an analytical column 2 and a plurality of multi-way valves, and is used to separate and detect the target.

[0013] Optionally or preferably, the gas sampling module includes a nitrogen input pipeline, a nitrogen purification tube, a pressure regulator and a multi-way valve;

[0014] The output end of the pressure regulator is connected to gas circuit 1, gas circuit 2, gas circuit 3, gas circuit 4, gas circuit 5, gas circuit 6 and gas circuit 7 respectively; the gas circuit 1 is connected to the input end of the multi-way valve 1, the gas circuit 2 is connected to the sample quantification module, and the gas circuit 3, gas circuit 4, gas circuit 5, gas circuit 6 and gas circuit 7 are respectively connected to the capture and analysis module and / or separation and detection module;

[0015] The input end of the multi-way valve 1 is also connected to an air sample inlet pipeline and a plurality of standard gas inlet pipelines; the output end of the multi-way valve 1 is connected to the sample quantification module.

[0016] Optionally or preferably, the sample quantification module comprises a multi-way valve 11, a multi-way valve 12, a multi-way valve 13 and a multi-way valve 14 connected in series in sequence;

[0017] The gas circuit 2 is connected to the multi-way valve 11, the multi-way valve 12, the multi-way valve 13, and the multi-way valve 14 in sequence and finally connected to the water sample pretreatment module;

[0018] The output end of the multi-way valve 1 is connected to the multi-way valve 11, the multi-way valve 12, the multi-way valve 13, and the multi-way valve 14 in sequence and is finally connected to the exhaust port.

[0019] Optionally or preferably, the water sample pretreatment module includes a second multi-way valve, a third multi-way valve and a fifteenth multi-way valve;

[0020] The multi-way valve 15 is used to control the flow of water sample into or out of the purge pipe;

[0021] The multi-way valve 2 is used to balance the pressure difference in the purge pipe during the process of the water sample entering the purge pipe;

[0022] The multi-way valve three is used to switch the purge gas through the purge pipe or bypass.

[0023] Optionally or preferably, the capture and analysis module includes a multi-way valve four, a multi-way valve five, a multi-way valve six, a multi-way valve seven and a multi-way valve eight;

[0024] The front collecting pipe includes a collecting pipe 1, and the rear collecting pipe includes a collecting pipe 2 and a collecting pipe 3;

[0025] The separation and detection module further includes a multi-way valve nine and a multi-way valve ten;

[0026] The pre-column 1 is connected to the system through the multi-way valve 9; the analytical column 1 and the detector 1 are connected to the system through the multi-way valve 10; the analytical column 2 and the detector 2 are connected to the system through the multi-way valve 8.

[0027] Optionally or preferably, the multi-way valve six, the multi-way valve eight, the multi-way valve nine and the multi-way valve ten are two-position four-way valves, each including a working port a, a working port b, a working port c, a working port d and a first working state and a second working state;

[0028] When the multi-way valve six and the multi-way valve eight are in the first working state, the working port a is connected to the working port b, and the working port c is connected to the working port d; when the multi-way valve six and the multi-way valve eight are in the second working state, the working port a is connected to the working port d, and the working port b is connected to the working port c; when the multi-way valve nine and the multi-way valve ten are in the first working state, the working port a is connected to the working port d, and the working port b is connected to the working port c; when the multi-way valve nine and the multi-way valve ten are in the second working state, the working port a is connected to the working port b, and the working port c is connected to the working port d;

[0029] The multi-way valve 3, multi-way valve 4 and multi-way valve 5 are two-position six-way valves, each including a working port a, a working port b, a working port c, a working port d, a working port e, a working port f and a first working state and a second working state;

[0030] When the multi-way valve 3, the multi-way valve 4 and the multi-way valve 5 are in the first working state, the working port a is connected to the working port b, the working port c is connected to the working port d, and the working port e is connected to the working port f; when the multi-way valve 3, the multi-way valve 4 and the multi-way valve 5 are in the second working state, the working port a is connected to the working port f, the working port b is connected to the working port c, and the working port d is connected to the working port e;

[0031] The multi-way valve seven is a two-position eight-way valve, including a working port a, a working port b, a working port c, a working port d, a working port e, a working port f, a working port g, and a working port h; when the multi-way valve seven is in a first working state, the working port a is connected to the working port h, the working port b is connected to the working port c, the working port d is connected to the working port e, and the working port f is connected to the working port g; when the multi-way valve seven is in a second working state, the working port a is connected to the working port b, the working port c is connected to the working port d, the working port e is connected to the working port f, and the working port g is connected to the working port h;

[0032] The sample pre-concentration and separation system for measuring trace substances in environmental water includes a tracer detection mode and a full substance mode. When the system is in the tracer detection mode, the flow path is in a first ready state. When the system is in the full substance mode, the flow path is in a second ready state.

[0033] In the first ready state, multi-way valves 3, 4, 5, 7 and 8 are all in the first working state; multi-way valves 6, 9 and 10 are in the second working state;

[0034] In the second ready state, multi-way valve three, multi-way valve four, multi-way valve five, multi-way valve six, multi-way valve seven and multi-way valve eight, multi-way valve nine, and multi-way valve ten are all in the first working state.

[0035] A method for measuring trace substances in environmental water, when the system is in tracer detection mode, includes the following process:

[0036] Water sample purge process: switch the flow path to the water sample purge state, at this time multi-way valve seven and multi-way valve eight are in the first working state; multi-way valve three, multi-way valve four, multi-way valve five, multi-way valve six, multi-way valve nine, and multi-way valve ten are in the second working state;

[0037] The purge gas passes through multi-way valve 11, multi-way valve 12, multi-way valve 13, multi-way valve 14, and multi-way valve 3 from gas line 2, and then enters the purge pipe. After passing through the water sample, the target gas is formed and passes through multi-way valve 2, drying and acid removal pipe 1, multi-way valve 3, and drying and acid removal pipe 2 in sequence. After the target gas removes the acid gas in drying and acid removal pipe 2, it enters the capture pipe 1 through multi-way valve 4. After the target gas is captured by the capture pipe 1, the remaining gas flows out of the capture pipe 1, passes through multi-way valve 5, and is discharged from the exhaust port.

[0038] Desorption process: Switch the flow path to the desorption state of the capture tube 1. At this time, multi-way valves 3, 4, 5, 6, and 8 are in the first working state; multi-way valves 7, 9, and 10 are in the second working state.

[0039] The temperature of the first trapping tube is raised. The carrier gas then flows from gas line four through multi-way valve six, multi-way valve five, the first trapping tube, multi-way valve four, multi-way valve nine, pre-column one, multi-way valve nine, multi-way valve six, multi-way valve seven, and the second trapping tube. The target compound is desorbed from the first trapping tube and pre-separated in the first pre-column. The first target compound with a shorter retention time preferentially enters the second trapping tube and is cryofocused in the second trapping tube. The remaining gas is discharged through the exhaust port.

[0040] Injection process: switch the flow path to the injection state. At this time, multi-way valve 3, multi-way valve 4, multi-way valve 5, multi-way valve 6, and multi-way valve 7 are in the first working state; multi-way valve 8, multi-way valve 9, and multi-way valve 10 are in the second working state;

[0041] At this time, the carrier gas flows from gas line 4 through multi-port valve 6, multi-port valve 5, trapping tube 1, multi-port valve 4, multi-port valve 9, pre-column 1, multi-port valve 9, multi-port valve 6, multi-port valve 7, multi-port valve 10, trapping tube 3, and analytical column 1. Target component 2, which has a longer retention time, flows out of pre-column 1 and follows the gas line into trapping tube 3, where it is cold-focused.

[0042] After the target component 2 is cryofocused in the capture tube 3, the capture tube 3 is heated, and the target component 2 then enters the analytical column 1 for separation and purification, and finally enters the detector 1 for detection;

[0043] At the same time, another carrier gas passes through gas line 5, multi-way valve 8, and reverses to capture tube 2, desorbing target component 1 from capture tube 2. The carrier gas then passes through multi-way valve 7 and enters pre-column 2. After passing through multi-way valve 8, the carrier gas is separated and purified in analytical column 2, and finally carries the target component into detector 2 for detection.

[0044] Optionally or preferably, when the system is in the tracer detection mode, it further includes a backflush process: switching the flow path to the backflush state, at which time the multi-way valve three and the multi-way valve eight are in the first working state; the multi-way valve four, the multi-way valve five, the multi-way valve six, the multi-way valve seven, the multi-way valve nine, and the multi-way valve ten are in the second working state;

[0045] At this time, the backflush gas passes through the multi-way valve 5, multi-way valve 6, multi-way valve 9, pre-column 1, multi-way valve 9, multi-way valve 4 from the gas line 3, and then is discharged through the exhaust port;

[0046] At the same time, backflush 7 passes through gas line 2 in sequence through multi-way valve 11, multi-way valve 12, multi-way valve 13, multi-way valve 14, multi-way valve 3, multi-way valve 4, capture pipe 1 and multi-way valve 5, and then is discharged through the exhaust port;

[0047] At the same time, the backflush gas passes through the multi-way valve 6, the multi-way valve 7, the capture tube 2, the multi-way valve 8, the pre-column 2, the multi-way valve 7, and then is discharged through the exhaust port.

[0048] Optionally or preferably, when the system is in full substance mode, the following processes are included:

[0049] Water sample purge process: switch the flow path to the water sample purge state. At this time, multi-way valve seven, multi-way valve eight, multi-way valve nine, and multi-way valve ten are in the first working state; multi-way valve three, multi-way valve four, multi-way valve five, and multi-way valve six are in the second working state;

[0050] The purge gas passes through multi-way valve 11, multi-way valve 12, multi-way valve 13, multi-way valve 14, and multi-way valve 3 from gas line 2, and then enters the purge pipe. After passing through the water sample, the target gas is formed and passes through multi-way valve 2, drying and acid removal pipe 1, multi-way valve 3, and drying and acid removal pipe 2 in sequence. After the target gas removes the acid gas in drying and acid removal pipe 2, it enters the capture pipe 1 through multi-way valve 4. After the target gas is captured by the capture pipe 1, the remaining gas flows out of the capture pipe 1, passes through multi-way valve 5, and is discharged from the exhaust port.

[0051] Desorption process: Switch the flow path to the desorption state of the capture tube 1. At this time, multi-way valve 3, multi-way valve 4, multi-way valve 5, multi-way valve 6, multi-way valve 8, multi-way valve 9, and multi-way valve 10 are in the first working state; multi-way valve 7 is in the second working state;

[0052] The temperature of the first trapping tube is raised. The carrier gas then flows from gas line 4 through multi-way valve 6, multi-way valve 5, the first trapping tube, the fourth trapping valve, the ninth trapping valve, the sixth trapping valve, the seventh trapping tube, the eighth trapping valve, the second pre-column, and the seventh pre-column. The target compound is desorbed from the first trapping tube and pre-separated in the second pre-column. The remaining gas passes through multi-way valve 7 and is discharged through the exhaust port.

[0053] Injection process: switch the flow path to the injection state. At this time, multi-way valve 3, multi-way valve 4, multi-way valve 5, multi-way valve 6, multi-way valve 7, multi-way valve 9, and multi-way valve 10 are in the first working state; multi-way valve 8 is in the second working state;

[0054] The carrier gas passes through gas line 5, multi-way valve 8, and then reversely passes through capture tube 2, and then passes through multi-way valve 7 to enter pre-column 2, and then passes through multi-way valve 8 to be separated and purified in analytical column 2, and finally carries the target into detector 2 for detection.

[0055] Optionally or preferably, when the system is in full substance mode, it further includes a backflush process: switching the flow path to the backflush state, at which time multi-way valve three, multi-way valve eight, multi-way valve nine, and multi-way valve ten are in the first working state; multi-way valve four, multi-way valve five, multi-way valve six, and multi-way valve seven are in the second working state;

[0056] At this time, the back-blowing gas passes through the multi-way valve 5, the multi-way valve 6, the multi-way valve 9, the multi-way valve 4 in sequence from the gas line 3, and then is discharged through the exhaust port;

[0057] At the same time, backflush 7 passes through gas line 2 in sequence through multi-way valve 11, multi-way valve 12, multi-way valve 13, multi-way valve 14, multi-way valve 3, multi-way valve 4, capture pipe 1 and multi-way valve 5, and then is discharged through the exhaust port;

[0058] At the same time, the backflush gas passes through the multi-way valve 6, the multi-way valve 7, the capture tube 2, the multi-way valve 8, the pre-column 2, the multi-way valve 7, and then is discharged through the exhaust port.

[0059] Based on the above technical solution, the present invention can produce at least the following technical effects:

[0060] The present invention provides a sample pre-concentration and separation system and method for measuring trace substances in environmental water. The system adopts multiple sets of capture tubes to meet the enrichment requirements of large-volume samples, and uses cold focusing (secondary capture) to narrow the target object spectrum band, thereby improving the sensitivity and separation effect of subsequent separation and detection.

[0061] By using two sets of pre-column and analytical column systems, the hierarchical separation of components with different properties is achieved. Substances with different separation activities can be effectively separated under flow switching, effectively avoiding confusion caused by similar functional groups, eliminating interference, and improving the separation degree and measurement sensitivity of the target objects; at the same time, the use of two sets of detectors can meet the needs of different sensitivity detection.

[0062] In addition, through the combination of multiple sample quantitative loops, quantitative combination of low-boiling point volatile trace gas standards with different contents can be achieved without changing the standard concentration, realizing batch external standard calibration; through the glass purge tube with volume calibration, the water sample injection volume can be directly read without additional measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 is a flow path arrangement diagram of the system of the present invention in a first ready state when in a tracer detection mode;

[0064] Figure 2 It is a flow path arrangement diagram of a water sample purge state when the system of the present invention is in a tracer detection mode;

[0065] Figure 3 is a flow path arrangement diagram of the system of the present invention in a desorption state when the system is in a tracer detection mode;

[0066] Figure 4 It is a flow path arrangement diagram of the system of the present invention in the sample injection state when the system is in the tracer detection mode;

[0067] Figure 5 is a flow path arrangement diagram of the system of the present invention in a backflush state when in a tracer detection mode;

[0068] Figure 6is a flow path arrangement diagram of the second ready state when the system of the present invention is in full substance mode;

[0069] Figure 7 It is a flow path arrangement diagram of the water sample purge state when the system of the present invention is in full substance mode;

[0070] Figure 8 It is a flow path arrangement diagram of the desorption state when the system of the present invention is in full material mode;

[0071] Figure 9 It is a flow path arrangement diagram of the injection state when the system of the present invention is in full substance mode;

[0072] Figure 10 It is a flow path arrangement diagram of the backflush state when the system of the present invention is in full substance mode;

[0073] Figure 11 This is a schematic diagram of the working port arrangement of the two-position four-way valve in the present invention. Figure 1 ;

[0074] Figure 12 This is a schematic diagram of the working port arrangement of the two-position four-way valve in the present invention. Figure 2 ;

[0075] Figure 13 This is a schematic diagram of the arrangement of the working ports of the two-position six-way valve of the present invention;

[0076] Figure 14 It is a schematic diagram of the arrangement of the working ports of the two-position eight-way valve in the present invention.

[0077] In the figure: 1. Pressure gauge; 2. On / Off valve; 3. Filter; 4. Drying and acid removal tube 1; 5. Drying and acid removal tube 2; 6. Pre-column 1; 7. Pre-column 2; 8. Analytical column 1; 9. Analytical column 2; 10. Nitrogen inlet pipe; 11. Nitrogen purge pipe; 12. Pressure regulator; 13. Air sample inlet pipe; 14. Standard gas inlet pipe; 15. Purge pipe; 16. Capture tube 1; 17. Capture tube 2; 18. Capture tube 3; 19. Detector 1; 20. Detector 2.

[0078] V1, multi-way valve one; V2, multi-way valve two; V3, multi-way valve three; V4, multi-way valve four; V5, multi-way valve five; V6, multi-way valve six; V7, multi-way valve seven; V8, multi-way valve eight; V9, multi-way valve nine; V10, multi-way valve ten; V11, multi-way valve eleven; V12, multi-way valve twelve; V13, multi-way valve thirteen; V14, multi-way valve fourteen; V15, multi-way valve fifteen;

[0079] L1, gas circuit 1; L2, gas circuit 2; L3, gas circuit 3; L4, gas circuit 4; L5, gas circuit 5; L6, gas circuit 6; L7, gas circuit 7;

[0080] P1, emptying port one; P2, emptying port two; P3, emptying port three; P4, emptying port four; P5, emptying port five; P6, emptying port six. DETAILED DESCRIPTION

[0081] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work shall fall within the scope of protection of the present invention. Example

[0082] See also Figures 1 to 10 A sample pre-concentration and separation system for measuring trace substances in environmental water bodies includes a gas injection module, a sample quantification module, a water sample pretreatment module, a capture and analysis module, and a separation and detection module that are interconnected.

[0083] In this embodiment, the gas sampling module is used to provide standard gas, purge gas and introduce sample source to the system, including nitrogen input pipeline 10, nitrogen purification pipe 11, pressure regulator 12 and multi-way valve V1. Nitrogen is input from the nitrogen input pipeline 10, enters the pressure regulator 12 for distribution after passing through the nitrogen purification pipe 11. In this embodiment, the pressure regulator 12 is provided with multiple output gas paths, including gas path 1 L1, gas path 2 L2, gas path 3 L3, gas path 4 L4, gas path 5 L5, gas path 6 L6 and gas path 7 L7. Seven L7, wherein gas circuit one L1 is connected to the multi-way valve one V1, gas circuit L2 is connected to the above-mentioned sample quantification module, gas circuit three L3, gas circuit four L4 and gas circuit five L5 are respectively connected to the capture and analysis module and / or separation and detection module; the pressure regulator 12 provides purge gas and carrier gas to the system by controlling the above-mentioned multiple gas circuits; the input end of the multi-way valve one V1 is also connected to at least two standard gas inlet pipes 14 and an air sample inlet pipe 13, wherein the air sample inlet pipe 13 is also provided with a filter 3.

[0084] The sample quantification module includes multiple quantitative loops and multi-way valve 11 V11, multi-way valve 12 V12, multi-way valve 13 V13 and multi-way valve 14 V14 connected in series in sequence; through multiple quantitative loops, quantitative combination of low-boiling point volatile trace gas standards with different contents can be achieved, and through multiple multi-way valves connected in series, the injection of standard gases of different volumes can be achieved.

[0085] In this embodiment, the multi-way valve eleven V11, the multi-way valve twelve V12, the multi-way valve thirteen V13, and the multi-way valve fourteen V14 are respectively connected to multiple quantitative rings of different sizes. The multi-way valve eleven V11, the multi-way valve twelve V12, the multi-way valve thirteen V13, and the multi-way valve fourteen V14 can achieve quantification of different gas sample injection volumes by switching the flow path; the multi-way valve eleven V11 is connected to the gas path one L1 through the multi-way valve one V1, and the end of the multi-way valve fourteen V14 is connected to the exhaust port two P2. At the front end of the exhaust port two P2, a precision pressure gauge 1 is also provided, and the pressure of the gas sample in the quantitative ring can be measured by the precision pressure gauge 1.

[0086] The water sample pretreatment module includes a graduated glass purge tube 15, drying and acid removal tube 1 4, drying and acid removal tube 2 5, multi-way valve 2 V2, multi-way valve 3 V3, and multi-way valve 15 V15. Multi-way valve 15 V15 is a three-way valve used to control the flow of water sample into or out of the purge tube 15. Multi-way valve 2 V2 is used to balance the pressure difference within the purge tube 15 during the process of water sample entering the purge tube 15. Multi-way valve 3 V3 is used to switch the purge gas through the purge tube 15 or bypass it. Specifically, the purge tube 15 includes an upper end connection port, a lower end connection port, and a side connection port. The upper end connection port is connected to multi-way valve 2 V2, the lower end connection port is connected to multi-way valve 3 V3, and the side connection port is connected to multi-way valve 15 V15.

[0087] In this embodiment, the drying and acid-removing tube 1 4 and the drying and acid-removing tube 2 5 both include a drying tube and an acid-removing tube, wherein the drying tube is filled with anhydrous magnesium perchlorate for absorbing the moisture contained in the sample gas; the acid-removing tube is filled with silica gel particles coated with sodium hydroxide for absorbing acidic gases such as CO2 contained in the sample gas.

[0088] The capture and analysis module is used to achieve the enrichment, cold focusing and transfer of the target object; it includes capture tube 1 16, capture tube 2 17, capture tube 3 18, multi-way valve 4 V4, multi-way valve 5 V5, multi-way valve 6 V6, multi-way valve 7 V7 and multi-way valve 8 V8; wherein the two ends of capture tube 1 16 are respectively connected to multi-way valve 4 V4 and multi-way valve 5 V5, and the two ends of capture tube 2 17 are respectively connected to multi-way valve 7 V7 and multi-way valve 8 V8.

[0089] In this embodiment, capture tube 16 serves as the pre-collection tube, while capture tubes 2 17 and 3 18 serve as post-collection tubes. The pre-collection tube has an inner diameter 2-3 times that of the post-collection tube. The target material is first pre-concentrated in capture tube 16 and then cryofocused in capture tube 2 17 or capture tube 3 18. All of these capture tubes are temperature-adjustable, allowing adjustment based on operational needs within a temperature range of -180°C to 300°C.

[0090] The separation and detection module is used to realize the detection and separation of the target object. In this embodiment, the separation and detection module includes a pre-column 1 6, a pre-column 2 7, an analytical column 1 8, an analytical column 2 9, a multi-way valve 9 V9 and a multi-way valve 10 V10; wherein the pre-column 1 6 is connected to the system through the multi-way valve 9 V9, the two ends of the pre-column 2 7 are respectively connected to the multi-way valve 7 V7 and the multi-way valve 8 V8, the analytical column 1 8 and the detector 19 are connected to the system through the multi-way valve 10 V10, and the analytical column 2 9 and the detector 2 20 are connected to the system through the multi-way valve 8 V8.

[0091] In this embodiment, the first detector 19 and the second detector 20 may be electron capture detectors (ECDs) that are sensitive to halogen compounds.

[0092] In addition, the multi-way valve nine V9 and the multi-way valve ten V10 are connected to the capture and analysis module through pipelines, which are used to switch the system mode and select whether the gas path passes through the pre-column one 6 and the analytical column one 19; when the system is in the tracer detection mode, the multi-way valve nine V9 and the multi-way valve ten V10 allow the gas path to pass through the pre-column one 6 to achieve preliminary separation of the target; when the system is in the full substance mode, the gas path bypasses the multi-way valve nine V9 and the multi-way valve ten V10, and the gas path does not pass through the pre-column one 6, and all substances are cold focused in the capture tube two 17.

[0093] See also Figures 11 to 12 In this embodiment, the multi-way valve six V6, the multi-way valve eight V8, the multi-way valve nine V9 and the multi-way valve ten V10 are two-position four-way valves, each including a working port a, a working port b, a working port c, a working port d and a first working state and a second working state;

[0094] When the multi-way valve six V6 and the multi-way valve eight V8 are in the first working state, the working port a is connected to the working port b, and the working port c is connected to the working port d; when the multi-way valve six V6 and the multi-way valve eight V8 are in the second working state, the working port a is connected to the working port d, and the working port b is connected to the working port c;

[0095] When the multi-way valve nine V9 and the multi-way valve ten V10 are in the first working state, the working port a is connected to the working port d, and the working port b is connected to the working port c; when the multi-way valve nine V9 and the multi-way valve ten V10 are in the second working state, the working port a is connected to the working port b, and the working port c is connected to the working port d;

[0096] See also Figure 13 The multi-way valve three V3, the multi-way valve four V4, and the multi-way valve five V5 are two-position six-way valves, each including a working port a, a working port b, a working port c, a working port d, a working port e, a working port f, and a first working state and a second working state;

[0097] When the multi-way valve three V3, the multi-way valve four V4, and the multi-way valve five V5 are in the first working state, the working port a is connected to the working port b, the working port c is connected to the working port d, and the working port e is connected to the working port f; when the multi-way valve three V3, the multi-way valve four V4, and the multi-way valve five V5 are in the second working state, the working port a is connected to the working port f, the working port b is connected to the working port c, and the working port d is connected to the working port e;

[0098] See also Figure 14 , the multi-way valve seven V7 is a two-position eight-way valve, including a working port a, a working port b, a working port c, a working port d, a working port e, a working port f, a working port g and a working port h; when the multi-way valve seven V7 is in a first working state, the working port a is connected to the working port h, the working port b is connected to the working port c, the working port d is connected to the working port e, and the working port f is connected to the working port g; when the multi-way valve seven V7 is in a second working state, the working port a is connected to the working port b, the working port c is connected to the working port d, the working port e is connected to the working port f, and the working port g is connected to the working port h;

[0099] In this embodiment, the sample pre-concentration and separation system for measuring trace substances in environmental water includes a tracer detection mode and a full substance mode. When the system is in the tracer detection mode, the flow path is in a first ready state; when the system is in the full substance mode, the flow path is in a second ready state.

[0100] In the first ready state, multi-way valve three V3, multi-way valve four V4, multi-way valve five V5, multi-way valve seven V7 and multi-way valve eight V8 are all in the first working state; multi-way valve six V6, multi-way valve nine V9 and multi-way valve ten V10 are in the second working state;

[0101] In the second ready state, multi-way valve three V3, multi-way valve four V4, multi-way valve five V5, multi-way valve six V6, multi-way valve seven V7, multi-way valve eight V8, multi-way valve nine V9, and multi-way valve ten V10 are all in the first working state.

[0102] The main difference between the aforementioned tracer detection mode and full-substance mode lies in the different operating states of multi-port valves V9 and V10. In tracer detection mode, the target is separated into different components, which are then cryofocused (secondary enrichment) in two trapping tubes and then separated and detected separately. This effectively avoids confusion caused by similar functional groups, eliminates interference, and improves target separation and measurement sensitivity. In full-substance mode, the system operates in full-substance mode, with all targets detected simultaneously on a single detector.

[0103] For ease of understanding, Figures 1 to 10A working status table of multi-way valve three V3, multi-way valve four V4, multi-way valve five V5, multi-way valve six V6, multi-way valve seven V7, multi-way valve eight V8, multi-way valve nine V9, and multi-way valve ten V10 is given, where "A" indicates that the multi-way valve is in the first working state, and "B" indicates that the multi-way valve is in the second working state; in addition, for the convenience of description and to avoid lengthy instructions, the flow path switching method of multi-way valve one V1, multi-way valve two V2, and multi-way valve fifteen V15 is omitted, and technical personnel can obtain the corresponding control method based on common knowledge.

[0104] In addition, in this embodiment, all components are connected through pipelines, and each exhaust port is provided with a switch valve and a flow meter. Example

[0105] This embodiment provides a method for measuring trace substances in environmental water based on the first embodiment. It should be noted that, for the convenience of description and understanding, the connection relationship between the gas path and the specific working ports in each multi-way valve is omitted in this embodiment. Those skilled in the art can easily understand it by combining the drawings or common knowledge.

[0106] When the system is in tracer detection mode, the following procedures are involved:

[0107] Water sample purge process: please refer to Figure 2 , the system switches the flow path from the first ready state to the water sample purge state. At this time, multi-way valve seven V7 and multi-way valve eight V8 are in the first working state; multi-way valve three V3, multi-way valve four V4, multi-way valve five V5, multi-way valve six V6, multi-way valve nine V9, and multi-way valve ten V10 are in the second working state;

[0108] The purge gas passes through the second gas line L2, in sequence, through the multi-way valve 11 V11, the 12th multi-way valve V12, the 13th multi-way valve V13, the 14th multi-way valve V14, and the 3rd multi-way valve V3, before entering the purge pipe 15. After passing through the water sample, the target gas is formed and passes through the second multi-way valve V2, the drying and acid removal pipe 14, the third multi-way valve V3, and the drying and acid removal pipe 2 5. After the acid gas is removed in the drying and acid removal pipe 2 5, the target gas passes through the fourth multi-way valve V4 and enters the capture pipe 16. At this time, the temperature of the capture pipe 16 is -80°C. The target gas is adsorbed by the capture pipe 16, and the remaining gas flows out of the capture pipe 16, passes through the fifth multi-way valve V5, and is discharged from the exhaust port 5 P5.

[0109] Desorption process: Switch the flow path to the desorption state of the collection tube 16. At this time, the multi-way valve 3 V3, the multi-way valve 4 V4, the multi-way valve 5 V5, the multi-way valve 6 V6, and the multi-way valve 8 V8 are in the first working state; the multi-way valve 7 V7, the multi-way valve 9 V9, and the multi-way valve 10 V10 are in the second working state;

[0110] The temperature of the first trapping tube 16 is raised to 90°C. The carrier gas from gas line 4 L4 then passes through multi-way valve 6 V6, multi-way valve 5 V5, the first trapping tube 16, multi-way valve 4 V4, multi-way valve 9 V9, pre-column 16, multi-way valve 9 V9, multi-way valve 6 V6, multi-way valve 7 V7, and the second trapping tube 17. The target compound is desorbed from the first trapping tube 16 and pre-separated within the pre-column 6. The target compound component 1 with the shorter retention time preferentially enters the second trapping tube 17 and is cryofocused (secondary enrichment) within the second trapping tube 17. The remaining gas is discharged through exhaust port 4 P4.

[0111] Injection process: switch the flow path to the injection state. At this time, multi-way valve three V3, multi-way valve four V4, multi-way valve five V5, multi-way valve six V6, and multi-way valve seven V7 are in the first working state; multi-way valve eight V8, multi-way valve nine V9, and multi-way valve ten V10 are in the second working state;

[0112] At this time, the carrier gas flows from gas line four L4 through multi-port valve six V6, multi-port valve five V5, capture tube one 16, multi-port valve four V4, multi-port valve nine V9, pre-column one 6, multi-port valve nine V9, multi-port valve six V6, multi-port valve seven V7, multi-port valve ten V10, capture tube three 18 and analytical column one 8 in sequence; the target compound component two with a longer retention time now flows out of pre-column one 6, follows the gas line into capture tube three 18 and is cryofocused (secondary enrichment) in capture tube three 18. At this time, the temperature in capture tube three 18 is -80°C.

[0113] After the target component 2 is cryofocused in the capture tube 3 18, the capture tube 3 18 is heated to 90°C. The target component 2 then enters the analytical column 1 8 for separation and purification, and finally enters the detector 19 for detection.

[0114] At the same time, another carrier gas passes through gas line five L5 and multi-way valve eight V8 in the reverse direction through capture tube two 17. At this time, the temperature of capture tube two 17 rises to 90°C, desorbing the target component one from capture tube two 17, and entering pre-column two 7 through multi-way valve seven V7 with the gas line, and then passing through multi-way valve eight V8 and separation and purification in analytical column two 9, and finally carrying the target into detector two 20 for detection.

[0115] Backflush process: switch the flow path to the backflush state. At this time, multi-way valve three V3 and multi-way valve eight V8 are in the first working state; multi-way valve four V4, multi-way valve five V5, multi-way valve six V6, multi-way valve seven V7, multi-way valve nine V9, and multi-way valve ten V10 are in the second working state.

[0116] At this time, the backflush gas passes through the gas line three L3 in sequence through the multi-way valve five V5, multi-way valve six V6, multi-way valve nine V9, pre-column one 6, multi-way valve nine V9, multi-way valve four V4, and then is discharged through the exhaust port three P3;

[0117] At the same time, backflush 7 passes through the gas line 2 L2 in sequence through the multi-way valve 11 V11, the multi-way valve 12 V12, the multi-way valve 13 V13, the multi-way valve 14 V14, the multi-way valve 3 V3, the multi-way valve 4 V4, the capture pipe 16 and the multi-way valve 5 V5, and then is discharged through the exhaust port 5 P5;

[0118] At the same time, the backflush gas passes through the multi-way valve six V6, the multi-way valve seven V7, the capture tube two I7, the multi-way valve eight V8, the pre-column two 7, the multi-way valve seven V7 from the gas line four L4 in sequence, and is then discharged through the exhaust port four P4.

[0119] When the system is in full substance mode, the following processes are involved:

[0120] Water sample purge process: switch the flow path to the water sample purge state. At this time, multi-way valve seven V7, multi-way valve eight V8, multi-way valve nine V9, and multi-way valve ten V10 are in the first working state; multi-way valve three V3, multi-way valve four V4, multi-way valve five V5, and multi-way valve six V6 are in the second working state;

[0121] The purge gas passes through the second gas line L2 in sequence through the multi-way valve 11 V11, the 12th multi-way valve V12, the 13th multi-way valve V13, the 14th multi-way valve V14, and the 3rd multi-way valve V3 before entering the purge pipe 15. After passing through the water sample, the target gas is formed and passes through the multi-way valve 2 V2, the drying and acid removal pipe 1 4, the multi-way valve 3 V3, and the drying and acid removal pipe 2 5 in sequence. After the target gas removes the acid gas in the drying and acid removal pipe 2 5, it passes through the multi-way valve 4 V4 and enters the capture pipe 1 16. After the target gas is captured by the capture pipe 1 16, the remaining gas flows out of the capture pipe 16, passes through the multi-way valve 5 V5, and is discharged from the exhaust port.

[0122] Desorption process: Switch the flow path to the desorption state of the collection tube 16. At this time, the multi-way valve 3 V3, multi-way valve 4 V4, multi-way valve 5 V5, multi-way valve 6 V6, multi-way valve 8 V8, multi-way valve 9 V9, and multi-way valve 10 V10 are in the first working state; the multi-way valve 7 V7 is in the second working state;

[0123] The temperature of the first trapping tube 16 is raised. The carrier gas then flows from the fourth gas line L4 through the sixth multi-way valve V6, the fifth multi-way valve V5, the first trapping tube 16, the fourth multi-way valve V4, the ninth multi-way valve V9, the sixth multi-way valve V6, the seventh multi-way valve V7, the second trapping tube 17, the eighth multi-way valve V8, the second pre-column 7, and the seventh multi-way valve V7. The target compound is desorbed from the first trapping tube 16 and pre-separated in the second pre-column 7. The remaining gas passes through the seventh multi-way valve V7 and is discharged through the exhaust port.

[0124] Injection process: switch the flow path to the injection state. At this time, multi-way valve three V3, multi-way valve four V4, multi-way valve five V5, multi-way valve six V6, multi-way valve seven V7, multi-way valve nine V9, and multi-way valve ten V10 are in the first working state; multi-way valve eight V8 is in the second working state;

[0125] The carrier gas passes through the gas line five L5, through the multi-way valve eight V8, and then passes through the capture tube two 17 in the reverse direction. It then passes through the multi-way valve seven V7 and enters the pre-column two 7. It then passes through the multi-way valve eight V8 and is separated and purified in the analytical column two 9, and finally carries the target substance into the detector two 20 for detection.

[0126] Backflush process: switch the flow path to the backflush state. At this time, multi-way valve three V3, multi-way valve eight V8, multi-way valve nine V9, and multi-way valve ten V10 are in the first working state; multi-way valve four V4, multi-way valve five V5, multi-way valve six V6, and multi-way valve seven V7 are in the second working state;

[0127] At this time, the back-blowing gas passes through the gas line 3 L3 in sequence through the multi-way valve 5 V5, the multi-way valve 6 V6, the multi-way valve 9 V9, the multi-way valve 4 V4, and then is discharged through the exhaust port;

[0128] At the same time, backflush 7 passes through the gas line 2 L2 in sequence through the multi-way valve 11 V11, the multi-way valve 12 V12, the multi-way valve 13 V13, the multi-way valve 14 V14, the multi-way valve 3 V3, the multi-way valve 4 V4, the capture pipe 16 and the multi-way valve 5 V5, and then is discharged through the exhaust port;

[0129] At the same time, the backflush gas passes through the gas line four L4 in sequence through the multi-way valve six V6, the multi-way valve seven V7, the capture tube two I7, the multi-way valve eight V8, the pre-column two 7, the multi-way valve seven V7, and then is discharged through the exhaust port.

[0130] When the system is in full substance mode, its flow path is roughly the same as that in tracer detection mode, with the main difference being that the pre-column 6, analytical column 8, and capture tube 3 18 are not connected to the target material gas path. Gas is supplied through gas line 7 L7 to maintain the gas path between capture tube 3 18 and analytical column 8. At this time, the pre-column 6 is in a closed state and is not connected to the gas path.

[0131] This embodiment provides a method for measuring trace substances in environmental water. In a dual-detector, dual-channel chromatographic column separation system, it can achieve separation and detection of targets of different concentrations and different sensitivity levels, so that the detection sensitivity of the target is consistent with its concentration, and the sampling volume does not need to be adjusted. At the same time, it can be adapted to different combinations of packed columns and capillary chromatographic columns to achieve wide-range trace halogenated gas detection.

[0132] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A sample pre-concentration and separation system for measuring trace substances in environmental water, characterized in that: include: A gas injection module, which is used to provide standard gas, purge gas and sample source to the system; A sample quantification module, the gas sampling module is connected to the sample quantification module, and the sample quantification module includes a plurality of quantitative loops and a plurality of multi-way valves connected in series for controlling and adjusting the sample amount; A water sample pretreatment module, the water sample pretreatment module comprising a purge pipe (15), a drying and acid removal pipe 1 (4), a drying and acid removal pipe 2 (5) and a plurality of multi-way valves; A capture and analysis module, wherein the gas sampling module and the water pretreatment module are respectively connected to the capture and analysis module, and the capture and analysis module includes a front capture tube, a rear capture tube and a plurality of multi-way valves for achieving the enrichment, cryofocusing and transfer of the target; A separation and detection module, comprising a pre-column 1 (6), a pre-column 2 (7), an analytical column 1 (8), an analytical column 2 (9), a detector 1 (19), a detector 2 (20) and a plurality of multi-way valves, for achieving separation and detection of a target; The gas sampling module includes a nitrogen input pipeline (10), a nitrogen purification pipe (11), a pressure regulator (12) and a multi-way valve (V1); The output end of the pressure regulator (12) is connected to gas circuit 1 (L1), gas circuit 2 (L2), gas circuit 3 (L3), gas circuit 4 (L4) and gas circuit 5 (L5), respectively; the gas circuit 1 (L1) is connected to the input end of the multi-way valve 1 (V1), the gas circuit 2 (L2) is connected to the sample quantification module, and the gas circuit 3 (L3), gas circuit 4 (L4) and gas circuit 5 (L5) are respectively connected to the capture and analysis module and / or the separation and detection module; The input end of the multi-way valve 1 (V1) is also connected to an air sample inlet pipe (13) and a plurality of standard gas inlet pipes (14); the output end of the multi-way valve 1 (V1) is connected to the sample quantification module; The sample quantification module comprises a multi-way valve eleven (V11), a multi-way valve twelve (V12), a multi-way valve thirteen (V13) and a multi-way valve fourteen (V14) connected in series in sequence; The gas circuit 2 (L2) is connected in sequence to the multi-way valve 11 (V11), the multi-way valve 12 (V12), the multi-way valve 13 (V13), and the multi-way valve 14 (V14) and finally connected to the water sample pretreatment module; The output end of the multi-way valve 1 (V1) is connected to the multi-way valve 11 (V11), the multi-way valve 12 (V12), the multi-way valve 13 (V13), the multi-way valve 14 (V14) in sequence and finally connected to the exhaust port; The water sample pretreatment module includes a multi-way valve 2 (V2), a multi-way valve 3 (V3) and a multi-way valve 15 (V15); The multi-way valve fifteen (V15) is used to control the flow of water sample into or out of the purge pipe (15); The multi-way valve 2 (V2) is used to balance the air pressure difference in the purge tube (15) during the process of the water sample entering the purge tube (15); The multi-way valve three (V3) is used to switch the purge gas through the purge pipe (15) or bypass; The capture and analysis module includes a multi-way valve four (V4), a multi-way valve five (V5), a multi-way valve six (V6), a multi-way valve seven (V7) and a multi-way valve eight (V8); The front collecting pipe includes a collecting pipe 1 (16), and the rear collecting pipe includes a collecting pipe 2 (17) and a collecting pipe 3 (18); The separation and detection module further includes a multi-way valve nine (V9) and a multi-way valve ten (V10); The pre-column 1 (6) is connected to the system through the multi-way valve 9 (V9); the analytical column 1 (8) and the detector 1 (19) are connected to the system through the multi-way valve 10 (V10); the analytical column 2 (9) and the detector 2 (20) are connected to the system through the multi-way valve 8 (V8); The multi-way valve six (V6), multi-way valve eight (V8), multi-way valve nine (V9) and multi-way valve ten (V10) are two-position four-way valves, each including a working port a, a working port b, a working port c, a working port d and a first working state and a second working state; When the multi-way valve six (V6) and the multi-way valve eight (V8) are in the first working state, the working port a is connected to the working port b, and the working port c is connected to the working port d; when the multi-way valve six (V6) and the multi-way valve eight (V8) are in the second working state, the working port a is connected to the working port d, and the working port b is connected to the working port c; when the multi-way valve nine (V9) and the multi-way valve ten (V10) are in the first working state, the working port a is connected to the working port d, and the working port b is connected to the working port c; when the multi-way valve nine (V9) and the multi-way valve ten (V10) are in the second working state, the working port a is connected to the working port b, and the working port c is connected to the working port d; The multi-way valve three (V3), multi-way valve four (V4), and multi-way valve five (V5) are two-position six-way valves, each including a working port a, a working port b, a working port c, a working port d, a working port e, a working port f, and a first working state and a second working state; When the multi-way valve three (V3), the multi-way valve four (V4), and the multi-way valve five (V5) are in the first working state, the working port a is connected to the working port b, the working port c is connected to the working port d, and the working port e is connected to the working port f; when the multi-way valve three (V3), the multi-way valve four (V4), and the multi-way valve five (V5) are in the second working state, the working port a is connected to the working port f, the working port b is connected to the working port c, and the working port d is connected to the working port e; The multi-way valve seven (V7) is a two-position eight-way valve, including a working port a, a working port b, a working port c, a working port d, a working port e, a working port f, a working port g and a working port h; when the multi-way valve seven (V7) is in a first working state, the working port a is connected to the working port h, the working port b is connected to the working port c, the working port d is connected to the working port e, and the working port f is connected to the working port g; when the multi-way valve seven (V7) is in a second working state, the working port a is connected to the working port b, the working port c is connected to the working port d, the working port e is connected to the working port f, and the working port g is connected to the working port h; The sample pre-concentration and separation system for measuring trace substances in environmental water includes a tracer detection mode and a full substance mode. When the system is in the tracer detection mode, the flow path is in a first ready state; when the system is in the full substance mode, the flow path is in a second ready state; In the first ready state, multi-way valve three (V3), multi-way valve four (V4), multi-way valve five (V5), multi-way valve seven (V7) and multi-way valve eight (V8) are all in the first working state; multi-way valve six (V6), multi-way valve nine (V9) and multi-way valve ten (V10) are in the second working state; In the second ready state, multi-way valve three (V3), multi-way valve four (V4), multi-way valve five (V5), multi-way valve six (V6), multi-way valve seven (V7), multi-way valve eight (V8), multi-way valve nine (V9), and multi-way valve ten (V10) are all in the first working state.

2. A method for measuring trace substances in environmental water, characterized in that: The sample pre-concentration and separation system according to claim 1 is used to measure trace substances in water, and when the system is in the tracer detection mode, the following process is included: Water sample purge process: switch the flow path to the water sample purge state, at this time multi-way valve seven (V7) and multi-way valve eight (V8) are in the first working state; multi-way valve three (V3), multi-way valve four (V4), multi-way valve five (V5), multi-way valve six (V6), multi-way valve nine (V9), and multi-way valve ten (V10) are in the second working state; The purge gas passes through the multi-way valve eleven (V11), the multi-way valve twelve (V12), the multi-way valve thirteen (V13), the multi-way valve fourteen (V14), and the multi-way valve three (V3) from the gas line two (L2) and then enters the purge pipe (15). After passing through the water sample, the target gas is formed and passes through the multi-way valve two (V2), the drying and acid removal pipe one (4), the multi-way valve three (V3) and the drying and acid removal pipe two (5) in sequence. After the target gas removes the acid gas in the drying and acid removal pipe two (5), it enters the capture pipe one (16) through the multi-way valve four (V4). After the target gas is captured by the capture pipe one (16), the remaining gas flows out of the capture pipe one (16) and is discharged from the exhaust port after passing through the multi-way valve five (V5). Desorption process: switch the flow path to the desorption state of the collection tube 1 (16), at this time, the multi-way valve 3 (V3), the multi-way valve 4 (V4), the multi-way valve 5 (V5), the multi-way valve 6 (V6), and the multi-way valve 8 (V8) are in the first working state; the multi-way valve 7 (V7), the multi-way valve 9 (V9), and the multi-way valve 10 (V10) are in the second working state; The temperature of the capture tube 1 (16) is increased, and the carrier gas is passed from the gas line 4 (L4) in sequence through the multi-way valve 6 (V6), the multi-way valve 5 (V5), the capture tube 1 (16), the multi-way valve 4 (V4), the multi-way valve 9 (V9), the pre-column 1 (6), the multi-way valve 9 (V9), the multi-way valve 6 (V6), the multi-way valve 7 (V7) and the capture tube 2 (17); the target substance is desorbed from the capture tube 1 (16) and pre-separated in the pre-column 1 (6); the target component 1 with a shorter retention time preferentially enters the capture tube 2 (17) and is cold-focused in the capture tube 2 (17), and the remaining gas is discharged through the exhaust port; Injection process: switch the flow path to the injection state. At this time, multi-way valve three (V3), multi-way valve four (V4), multi-way valve five (V5), multi-way valve six (V6), and multi-way valve seven (V7) are in the first working state; multi-way valve eight (V8), multi-way valve nine (V9), and multi-way valve ten (V10) are in the second working state; At this time, the carrier gas flows from gas line four (L4) through multi-way valve six (V6), multi-way valve five (V5), capture tube one (16), multi-way valve four (V4), multi-way valve nine (V9), pre-column one (6), multi-way valve nine (V9), multi-way valve six (V6), multi-way valve seven (V7), multi-way valve ten (V10), capture tube three (18) and analytical column one (8); target component two with a longer retention time flows out of pre-column one (6) at this time, follows the gas line into capture tube three (18) and is cold-focused in capture tube three (18); After the target component 2 is cryofocused in the capture tube 3 (18), the capture tube 3 (18) is heated, and the target component 2 then enters the analytical column 1 (8) for separation and purification, and finally enters the detector 1 (19) for detection; At the same time, another carrier gas passes through gas line five (L5) through multi-way valve eight (V8) and then passes through capture tube two (17) in the reverse direction, desorbing target component one from capture tube two (17), and then passes through multi-way valve seven (V7) along the gas line into pre-column two (7), and then passes through multi-way valve eight (V8) and is separated and purified in analytical column two (9), and finally carries the target into detector two (20) for detection.

3. The method for measuring trace substances in environmental water according to claim 2, characterized in that: When the system is in the tracer detection mode, it also includes a backflush process: the flow path is switched to the backflush state, at which time multi-way valve three (V3) and multi-way valve eight (V8) are in the first working state; multi-way valve four (V4), multi-way valve five (V5), multi-way valve six (V6), multi-way valve seven (V7), multi-way valve nine (V9), and multi-way valve ten (V10) are in the second working state; At this time, the backflush gas passes through the gas line three (L3) in sequence through the multi-way valve five (V5), multi-way valve six (V6), multi-way valve nine (V9), pre-column one (6), multi-way valve nine (V9), multi-way valve four (V4), and then is discharged through the exhaust port; At the same time, backflush seven passes through gas line two (L2) in sequence through multi-way valve eleven (V11), multi-way valve twelve (V12), multi-way valve thirteen (V13), multi-way valve fourteen (V14), multi-way valve three (V3), multi-way valve four (V4), capture pipe one (16) and multi-way valve five (V5), and then is discharged through the exhaust port; At the same time, the backflush gas passes through the multi-way valve six (V6), multi-way valve seven (V7), capture tube two (17), multi-way valve eight (V8), pre-column two (7), multi-way valve seven (V7) from gas line four (L4) in sequence, and is then discharged through the exhaust port.

4. The method for measuring trace substances in environmental water according to claim 2, characterized in that: When the system is in full substance mode, it includes the following processes: Water sample purge process: switch the flow path to the water sample purge state. At this time, multi-way valve seven (V7), multi-way valve eight (V8), multi-way valve nine (V9), and multi-way valve ten (V10) are in the first working state; multi-way valve three (V3), multi-way valve four (V4), multi-way valve five (V5), and multi-way valve six (V6) are in the second working state; The purge gas passes through the multi-way valve eleven (V11), the multi-way valve twelve (V12), the multi-way valve thirteen (V13), the multi-way valve fourteen (V14), and the multi-way valve three (V3) from the gas line two (L2) and then enters the purge pipe (15). After passing through the water sample, the target gas is formed and passes through the multi-way valve two (V2), the drying and acid removal pipe one (4), the multi-way valve three (V3) and the drying and acid removal pipe two (5) in sequence. After the target gas removes the acid gas in the drying and acid removal pipe two (5), it enters the capture pipe one (16) through the multi-way valve four (V4). After the target gas is captured by the capture pipe one (16), the remaining gas flows out of the capture pipe one (16) and is discharged from the exhaust port after passing through the multi-way valve five (V5). Desorption process: switch the flow path to the desorption state of the capture tube 1 (16), at this time, the multi-way valve 3 (V3), the multi-way valve 4 (V4), the multi-way valve 5 (V5), the multi-way valve 6 (V6), the multi-way valve 8 (V8), the multi-way valve 9 (V9), and the multi-way valve 10 (V10) are in the first working state; the multi-way valve 7 (V7) is in the second working state; The temperature of the collecting tube 1 (16) is increased, and the carrier gas is passed from the gas line 4 (L4) in sequence through the multi-way valve 6 (V6), the multi-way valve 5 (V5), the collecting tube 1 (16), the multi-way valve 4 (V4), the multi-way valve 9 (V9), the multi-way valve 6 (V6), the multi-way valve 7 (V7), the collecting tube 2 (17), the multi-way valve 8 (V8), the pre-column 2 (7) and the multi-way valve 7 (V7); the target is desorbed from the collecting tube 1 (16), and pre-separated in the pre-column 2 (7), and the remaining gas passes through the multi-way valve 7 (V7) and is discharged through the exhaust port; Injection process: switch the flow path to the injection state. At this time, multi-way valve three (V3), multi-way valve four (V4), multi-way valve five (V5), multi-way valve six (V6), multi-way valve seven (V7), multi-way valve nine (V9), and multi-way valve ten (V10) are in the first working state; multi-way valve eight (V8) is in the second working state; The carrier gas passes through the gas line five (L5) through the multi-way valve eight (V8) and then passes through the capture tube two (17) in the reverse direction. It then passes through the multi-way valve seven (V7) and enters the pre-column two (7). It then passes through the multi-way valve eight (V8) and is separated and purified in the analytical column two (9). Finally, it carries the target substance into the detector two (20) for detection.

5. The method for measuring trace substances in environmental water according to claim 4, characterized in that: When the system is in full-substance mode, it also includes a backflush process: the flow path is switched to the backflush state, at which time multi-way valve three (V3), multi-way valve eight (V8), multi-way valve nine (V9), and multi-way valve ten (V10) are in the first working state; multi-way valve four (V4), multi-way valve five (V5), multi-way valve six (V6), and multi-way valve seven (V7) are in the second working state; At this time, the back-blowing gas passes through the gas line 3 (L3) in sequence through the multi-way valve 5 (V5), the multi-way valve 6 (V6), the multi-way valve 9 (V9), the multi-way valve 4 (V4), and then is discharged through the exhaust port; At the same time, backflush seven passes through gas line two (L2) in sequence through multi-way valve eleven (V11), multi-way valve twelve (V12), multi-way valve thirteen (V13), multi-way valve fourteen (V14), multi-way valve three (V3), multi-way valve four (V4), capture pipe one (16) and multi-way valve five (V5), and then is discharged through the exhaust port; At the same time, the backflush gas passes through the multi-way valve six (V6), multi-way valve seven (V7), capture tube two (17), multi-way valve eight (V8), pre-column two (7), multi-way valve seven (V7) from gas line four (L4) in sequence, and is then discharged through the exhaust port.

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