Gas chromatography continuous sampling device and application thereof in rapid screening of specific target object

Abstract

The invention discloses a gas chromatography continuous sampling device and application thereof in rapid screening of a specific target object, and belongs to the technical field of analytical instruments. The continuous sampling device comprises a shell, a damping column, a partial pressure valve, a control system and a display controller, and the damping column plays a role of a channel for connecting a vaporizing chamber and the partial pressure valve and can realize pre-separation of a solvent and a target compound. The pressure dividing valve is a multi-way valve capable of switching fluid paths, a first air outlet of the pressure dividing valve is connected with the emptying pipe, and a second air outlet of the pressure dividing valve is connected with the chromatographic column; and fractions can be emptied in a preset time period, so that the removal of solvent peaks is realized. The application of the continuous sample injection device realizes removal of a solvent peak, ensures that a solvent and a target compound can be separated on a damping column base line, overcomes the pulse solvent peak caused by traditional continuous sample injection, and reduces the influence of covering or flattening the peak pattern of the target compound in the front section. And finally, rapid and accurate detection of a large batch of samples is realized, the detection time is saved, and the detection efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of analytical instruments, and in particular relates to a gas chromatography continuous sampling device and an application thereof in rapid screening of specific targets. Background Art

[0002] Gas chromatography is an analytical instrument that mainly uses the molecular weight and polarity of gaseous compound molecules and the difference in their retention time on the chromatographic column to achieve separation between different compounds. After the sample to be analyzed is vaporized in the vaporization chamber, it is carried into the chromatographic column by an inert gas (i.e., carrier gas, also called mobile phase). The column contains a liquid or solid stationary phase. Due to the different molecular weights and polarities of the components in the sample, each component tends to form a distribution or adsorption equilibrium between the mobile phase and the stationary phase. The smaller the molecular weight, the faster the initial velocity of the molecule in the chromatogram, and the closer the molecular polarity is to the polarity of the stationary phase of the chromatographic column, the easier it is to be retained by the chromatographic column. Taking into account factors such as the initial velocity of the molecule and the retention capacity of the chromatographic column, the components are gradually separated in the chromatographic column. When the components flow out of the chromatographic column, they enter the detector. The detector converts the sample components into electrical signals for measurement, and can perform qualitative and quantitative analysis. It is widely used in detection in the fields of petroleum, chemical industry, biochemistry, medicine and health, food industry, environmental protection, etc.

[0003] At present, detection technologies are mainly divided into rapid detection and precise detection. Rapid detection is mainly based on enzyme-linked immunosorbent or colloidal gold rapid test kits, which can achieve qualitative or semi-quantitative detection in a relatively short time; precise detection is mainly based on chromatography or chromatography-mass spectrometry, which can achieve precise quantitative detection, but it consumes more time and manpower. The main reason for the high time cost is that samples need to be injected one by one, and one can only start to detect the next one after completing one. In this way, the total detection time of large batches of samples is much longer than that of rapid detection devices such as rapid test kits. Therefore, if continuous injection and simultaneous detection of multiple samples can be achieved, the total time for precise detection will be greatly shortened, becoming a key technology for achieving rapid and precise detection.

[0004] The principle, structure, materials used, injection temperature, injection volume, injection speed, injection tools, etc. of the injection method and injection system will have a direct impact on the repeatability and accuracy of quantitative and qualitative gas chromatography analysis. At present, there is no mature detection technology that can directly achieve rapid and accurate detection. The common practice is to optimize the instrument parameters for the compounds to be tested to shorten the detection time, and to purchase more instruments and equipment to detect large quantities of samples at the same time. Optimizing instrument parameters to shorten the detection time has a very limited effect on reducing time costs and cannot fundamentally solve the problem of long detection time; and purchasing more chromatographs or mass spectrometers will greatly increase costs and is not easy to achieve.

[0005] Moreover, in the existing gas chromatography detection system, the solenoid valve is used to control the flow of gas and the regulation of pressure. However, the inner surface of the existing solenoid valve will adhere to the sample matrix. As the number of sample matrices increases, it will cause contamination to the subsequent sample analysis, and the valve core block is also prone to jamming, which reduces the sealing performance of the solenoid valve for the inlet and outlet. Therefore, the solenoid valve needs to be disassembled from the object and then its outer shell before it can be cleaned, which reduces the convenience of operation and increases the burden of cleaning the solenoid valve.

[0006] The present invention aims to provide a gas chromatography continuous sampling device, which can realize the continuous supply and analysis of samples without interrupting chromatographic separation, and finally realize the rapid and accurate detection of large batches of samples and facilitate the cleaning of impurities inside the solenoid valve. Summary of the invention

[0007] The purpose of the present invention is to solve the problem that the chromatographic technology in the background technology has a long detection time and cannot realize the rapid detection of large quantities of samples, which restricts its application in the field of rapid screening and rapid detection. A gas chromatography continuous sampling device is provided, which can realize the continuous supply and analysis of samples without interrupting chromatographic separation, and finally realize the rapid and accurate detection of large quantities of samples, and its application in the rapid screening of specific targets. The gas chromatography continuous sampling device can realize the continuous sampling of large sample volumes, and is convenient for cleaning impurities inside the continuous sampling device.

[0008] To achieve the above object, the present invention provides the following technical solutions: A gas chromatography continuous sampling device comprises a shell, a damping column, a pressure dividing valve, a control system and a display controller, wherein the damping column and the pressure dividing valve are installed inside the shell; the front end of the damping column is connected to the outlet of a vaporization chamber, and the rear end thereof is connected to the air inlet of the pressure dividing valve, so as to serve as a channel connecting the vaporization chamber and the pressure dividing valve and to achieve pre-separation of a solvent and a target compound; the pressure dividing valve is a multi-channel valve that can switch the fluid paths between channels, and can empty the fractions in a predetermined time period to achieve removal of the solvent peak; the pressure dividing valve is provided with a first air outlet and a second air outlet, the first air outlet of the pressure dividing valve is connected to an exhaust pipe through a pipeline to exhaust the exhausted gas; the second air outlet of the pressure dividing valve is connected to a chromatographic column through a pipeline; the pressure dividing valve, the control system and the display controller are electrically connected through a control circuit.

[0009] Preferably: the pressure dividing valve includes an electromagnetic valve body, the surface of the electromagnetic valve body is respectively provided with an air inlet, a first air outlet and a second air outlet, a valve core block is matched and installed inside the electromagnetic valve body, two symmetrical sides of the valve core block are respectively provided with a second movable rod and a first movable rod, one end of the second movable rod and the first movable rod penetrates the surface of the electromagnetic valve body and extends to the outside thereof, a fixed iron core is movably sleeved on the surface of the second movable rod and the first movable rod, the fixed iron core is installed on the outside of the electromagnetic valve body, one end of the second movable rod and the first movable rod are both fixedly sleeved with a moving iron core, the positions of the moving iron core and the fixed iron core correspond, and an electromagnetic coil is sleeved around the moving iron core and the fixed iron core.

[0010] Preferably: the valve core block is a hollow structure, two annular water bags are arranged inside the valve core block, a push plate is bonded to the surface of the annular water bag, a plurality of first fixed hollow pipes are installed through the surface of the push plate, a compression spring is sleeved on the surface of the first fixed hollow pipe, the two ends of the compression spring are respectively installed on the surfaces of the valve core block and the push plate, one end of the plurality of first fixed hollow pipes are installed through the surface of the annular water bag, a plurality of stepped holes corresponding to the positions of the first fixed hollow pipes are opened on two symmetric sides of the valve core block, a mounting block is matched inside the stepped holes, a mounting groove is opened on the side of the mounting block, and the first fixed hollow pipe The other end of the component extends to the interior of the mounting groove, and the surface of the mounting block is provided with a first flow channel connected to the mounting groove, and the internal thread of the first flow channel is provided with a first nozzle, and the positions of the first nozzle and the inner surface of the solenoid valve body correspond to each other, and the second movable rod is a hollow structure, and the other end of the second movable rod passes through the side of the valve core block and the side of the push plate in sequence and extends to the inner hole of the annular water bag, one end of the second movable rod extends to one side of the moving iron core, and one end of the second movable rod is provided with a fixed water pipe through a piston sealing gasket, and one end of the fixed water pipe is connected to a water pump through a water pipe, and the second movable rod and the two annular water bags are fixed by a movable connection mechanism.

[0011] Preferably, the liquid injected into the annular water bag for cleaning is water or an organic solvent.

[0012] Preferably: the movable connection mechanism includes a first connecting tube and a second connecting tube, one end of the first connecting tube is welded with a fixed hollow tube, one end of the fixed hollow tube extends to the interior of the second connecting tube, the fixed hollow tube and the second connecting tube are sealed by a piston sealing gasket, one end of the second connecting tube is welded to the end of the second movable rod, and the surfaces of the first connecting tube and the second connecting tube are penetrated by a plurality of second fixed hollow tubes, and one ends of the plurality of second fixed hollow tubes are respectively penetrated and installed on the surfaces of two annular water bags.

[0013] Preferably, a plurality of second flow channels communicating with the mounting grooves are provided inside the mounting block, a plurality of second nozzles communicating with the second flow channels are embedded on the side of the mounting block, and the second nozzles are arranged obliquely.

[0014] Preferably: a first mounting sleeve is sleeved between the surfaces of the moving iron core and the fixed iron core, one end of the first mounting sleeve is mounted on the outside of the solenoid valve body, the electromagnetic coil is sleeved on the outside of the first mounting sleeve, and one end of the second movable rod passes through the surface of the first mounting sleeve and extends to its outside.

[0015] Preferably: a tension spring is installed on the inner surface of the first installation sleeve, and one end of the tension spring is installed on the surface of the moving iron core.

[0016] Preferably, a second mounting sleeve is provided around the electromagnetic coil, and one end of the second mounting sleeve is mounted outside the electromagnetic valve body.

[0017] Another object of the present invention is to provide a gas chromatography continuous sampling device and its application in the rapid screening of specific targets: the continuous sampling device includes a housing, a damping column, a pressure divider valve, a control system and a display controller, and the above-mentioned continuous sampling device is used to build a gas phase-continuous sampling device platform. The damping column acts as a channel connecting the vaporization chamber and the pressure divider valve, and can realize the pre-separation of the solvent and the target compound. The pressure divider valve is a multi-channel valve that can switch the fluid path between the channels, and its first gas outlet is connected to the emptying pipe, and the second gas outlet is connected to the chromatographic column; it can empty the fraction in a predetermined time period to achieve the removal of the solvent peak. Ensure that the solvent and the target compound can be separated at the damping column baseline, and determine the corresponding retention time, and fully consider the retention time range to set the pressure divider valve parameters, such as emptying 20 to 30 seconds after each injection, and at the same time, avoid the target compound from distilling out during this time period, and then transport the target compound to the chromatographic column through the pressure divider valve, and the detector performs quantitative analysis on it.

[0018] The gas chromatography continuous sampling device and its application in the rapid screening of specific targets specifically include the following operating steps: S1, start-up balance: start the machine, control the system to work, control the valve core block to close the first gas outlet (9), the sample inlet of the injector is connected to the gas inlet of the pressure divider valve through the damping column, and a passage is formed with the second gas outlet, the second gas outlet is connected to the chromatographic column, the chromatographic column is connected to the detector, and the balancing instrument is started; S2, setting time: setting the connection time between the air inlet and the second air outlet of the pressure divider valve to C1, C2, C3...Cn through the display controller, where n is the number of injections; setting the emptying time between the air inlet and the first air outlet of the pressure divider valve to E1, E2, E3...En, where n is the number of injections; S3, pressure-dividing valve emptying: the control system works, and after the time reaches the input conditions of time E1, E2, E3...En, the valve core block closes the second air outlet; the pressure-dividing valve air inlet and the first air outlet form a passage, and the first air outlet is connected to the emptying pipe to perform the emptying operation; S4, pressure divider valve injection: the control system works, and when the time reaches the input condition time C1, C2, C3...Cn, the valve core block closes the first gas outlet, the pressure divider valve inlet is connected to the second gas outlet, the second gas outlet is connected to the chromatographic column, and is connected to the detector, and the injection detection operation is performed; S5, shutdown operation: After completing the continuous sampling test of this batch, the control system controls the valve core block to close the first air outlet to prevent external pollution from entering the valve body of the pressure dividing valve (3) through the exhaust pipe and causing pollution, and then shuts down the operation.

[0019] Compared with the prior art, the continuous sampling of the present invention has the following beneficial effects: 1. The gas chromatography continuous sampling device of the present invention empties the fractions through a pressure divider valve to remove the solvent peak, ensuring that the solvent and the target compound can be separated at the damping column baseline, overcoming the problem that continuous sampling will cause a pulsed solvent peak, reducing the influence of covering or flattening the peak shape of the target compound in the front section, and thus realizing continuous supply and analysis of samples without interrupting chromatographic separation, and ultimately realizing rapid and accurate detection of large quantities of samples.

[0020] 2. The gas chromatography continuous sampling device of the present invention arranges a first nozzle, a water bag and a water pump in the solenoid valve, so that impurities inside the solenoid valve can be cleaned conveniently with water or an organic solvent without disassembling the solenoid valve, thus saving operation steps and improving the convenience of operation.

[0021] 3. The gas chromatography continuous sampling device of the present invention is applied to the rapid screening of specific targets, realizing the continuous sampling and analysis of samples, and finally realizing the rapid and accurate detection of large batches of samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of the continuous sampling device of the present invention connected to a gas chromatograph; Figure 2 It is a structural schematic diagram of the pressure dividing valve of the present invention; Figure 3 It is a structural cross-sectional view of the pressure dividing valve of the present invention; Figure 4 It is a schematic diagram of the internal structure of the valve core block of the present invention; Figure 5 It is a schematic diagram of the valve core block structure of the present invention; Figure 6 It is a schematic diagram of the connection structure of the mounting block, the push plate and the water bag of the present invention; Figure 7 It is a schematic diagram of the connection structure of the second movable rod, the first connecting pipe and the second connecting pipe of the present invention; Figure 8 It is a schematic diagram of the connection structure between the first fixed hollow pipe member and the mounting block of the present invention; Fig. 9 It is a schematic diagram of the connection structure of the mounting block, the first nozzle and the second nozzle of the present invention; Fig.10 This is a gas chromatogram (100 ppb) of a single injection test of diazinon in Example 2 of the present invention; Fig.11 This is a gas chromatogram (100 ppb) of continuous sampling detection of diazinon in Example 2 of the present invention; Fig.12 The single injection gas chromatogram (200 ppb) of propyl bromide in Example 3 of the present invention; Fig.13 The continuous sampling and detection gas chromatogram of propyl bromide in Example 3 of the present invention (200 ppb); Fig.14 This is a gas chromatogram (200 ppb) of a single injection detection of phosalone in Example 4 of the present invention; Fig.15 This is a gas chromatogram (200 ppb) of the continuous sampling and detection of phosalone in Example 4 of the present invention; Fig.16 This is the total ion current diagram of the solvent peak detected by a single injection of methyl nonanoate in Example 5 of the present invention; Fig.17 is the standard mass spectrum of methyl nonanoate of Example 5 of the present invention; Fig.18 This is the selected ion current diagram of continuous injection of methyl nonanoate of different concentrations in Example 5 of the present invention.

[0023] In the figure: shell 1, damping column 2, pressure dividing valve 3, control system 4, display controller 5, exhaust pipe 6, first installation sleeve 7, fixed water pipe 8, first air outlet 9, second air outlet 10, second movable rod 11, electromagnetic coil 12, tension spring 13, moving iron core 14, fixed iron core 15, first movable rod 16, installation block 17, valve core block 18, compression spring 19, annular water bag 20, push plate 21, first fixed hollow pipe 22, second fixed hollow pipe 23, first connecting pipe 24, third fixed hollow pipe 25, first flow channel 26, first nozzle 27, second nozzle 28, installation groove 29, electromagnetic valve body 30, air inlet 31, second installation sleeve 32, water pump 33, stepped hole 34, second flow channel 35, second connecting pipe 36, injector 37, chromatographic column 38, detector 39. DETAILED DESCRIPTION

[0024] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, a detailed description is given below with reference to the accompanying drawings and specific embodiments.

[0025] Example 1 Gas Chromatography Continuous Sampling Device like Figures 1 to 9 As shown, a gas chromatography continuous sampling device comprises a shell 1, a damping column 2, a pressure dividing valve 3, a control system 4 and a display controller 5, wherein the damping column 2 and the pressure dividing valve 3 are installed inside the shell 1; the front end of the damping column 2 is connected to the outlet of the vaporization chamber of the sample injector 37, and the rear end thereof is connected to the air inlet 31 of the pressure dividing valve 3, which serves as a channel connecting the vaporization chamber and the pressure dividing valve, and can realize the pre-separation of the solvent and the solute; the pressure dividing valve 3 is a multi-channel valve that can switch the fluid path between the channels, and can empty the fraction in a predetermined time period to realize the removal of the solvent peak; the pressure dividing valve 3 is provided with a first air outlet 9 and a second air outlet 10, and the first air outlet 9 of the pressure dividing valve 3 is connected to the exhaust pipe 6 through a pipeline to discharge the exhausted gas; the second air outlet 10 of the pressure dividing valve 3 is connected to the chromatographic column 38 through a pipeline; the pressure dividing valve 3, the control system 4 and the display controller 5 are electrically connected through a control circuit. The sample injector 37 vaporizes the test liquid and conveys it to the damping column 2 for pre-separation of the components, thereby realizing simple separation of the solvent and the target compound of the test compound. The pressure divider valve 3 empties the fraction in a specific time period to realize the removal of the solvent peak and determine the corresponding retention time. The parameters of the pressure divider valve 3 are set by fully considering the retention time range, such as emptying it 20 to 30 seconds after each injection, while preventing the target compound from distilling out during this time period. The target compound is then conveyed to the chromatographic column 38 via the pressure divider valve 3. The detector 39 is a mass spectrometer detector for quantitative analysis of the target compound. The first gas outlet 9 is connected to the exhaust pipe 6 to exhaust the exhausted gas.

[0026] The pressure-dividing valve 3 comprises an electromagnetic valve body 30, on the surface of which an air inlet 31, a first air outlet 9 and a second air outlet 10 are respectively provided, and a valve core block 18 is matched and installed inside the electromagnetic valve body 30, and two symmetrical sides of the valve core block 18 are respectively provided with a second movable rod 11 and a first movable rod 16, one end of the second movable rod 11 and the first movable rod 16 penetrate the surface of the electromagnetic valve body 30 and extend to the outside thereof, and a fixed iron core 15 is movably sleeved on the surface of the second movable rod 11 and the first movable rod 16, and the fixed iron core 15 is installed on the outside of the electromagnetic valve body 30, and one end of the second movable rod 11 and the first movable rod 16 are fixedly sleeved with a moving iron core 14, and the positions of the moving iron core 14 and the fixed iron core 15 correspond, and the moving iron core 14 and the fixed iron core 15 are sleeved with an electromagnetic coil 12 around them; Figure 2As shown, after the electromagnetic coil 12 on the left is energized, the fixed iron core 15 and the moving iron core 14 both generate magnetic force. Since the position of the fixed iron core 15 is fixed, due to the mutual attraction of the magnetic forces, the moving iron core 14 moves toward the fixed iron core 15, and the moving iron core 14 drives the first movable rod 16 to push the valve core block 18 to move. After the moving iron core 14 contacts the fixed iron core 15, the valve core block 18 moves to the position corresponding to the first air outlet 9. At this time, the air inlet 31 and the second air outlet 10 form a passage, which facilitates the gas. Conveying; by the same token, after the right electromagnetic coil 12 is energized, the moving iron core 14 moves toward the fixed iron core 15, and the moving iron core 14 drives the second movable rod 11 to slide in the fixed water pipe 8. At the same time, the second movable rod 11 pushes the valve core block 18 to move synchronously. After the moving iron core 14 contacts the fixed iron core 15, the valve core block 18 moves to a position corresponding to the second air outlet 10. At this time, the air inlet 31 and the first air outlet 9 form a passage, which is convenient for emptying the distillate in a specific time period and realizing the removal of the solvent peak.

[0027] The valve core block 18 is a hollow structure. Two annular water bags 20 are bonded to the inside of the valve core block 18. A push plate 21 is bonded to the surface of the annular water bag 20. A plurality of first fixed hollow pipes 22 are installed through the surface of the push plate 21. A compression spring 19 is sleeved on the surface of the first fixed hollow pipe 22. The two ends of the compression spring 19 are respectively installed on the surfaces of the valve core block 18 and the push plate 21. One end of the plurality of first fixed hollow pipes 22 is installed through the surface of the annular water bag 20. The two symmetrical surfaces of the valve core block 18 are provided with a plurality of stepped holes 34 corresponding to the positions of the first fixed hollow pipes 22. The inside of the stepped holes 34 is matched with a mounting block 17. The side of the mounting block 17 is provided with a mounting groove 29. The first fixed hollow pipe 22 The other end of the second movable rod 11 extends to the inside of the mounting groove 29, and the surface of the mounting block 17 is provided with a first flow channel 26 connected to the mounting groove 29. The first flow channel 26 is internally threaded with a first nozzle 27, and the position of the first nozzle 27 corresponds to the inner surface of the electromagnetic valve body 30. The second movable rod 11 is a hollow structure, and the other end of the second movable rod 11 passes through the side of the valve core block 18 and the side of the push plate 21 in sequence and extends to the inner hole of the annular water bag 20, wherein the second movable rod 11 and the valve core block 18 are fixed by screws, and the push plate 21 and the second movable rod 11 are movably connected, and one end of the second movable rod 11 extends to one side of the moving iron core 14, and one end of the second movable rod 11 is provided with a fixed water pipe 8 through a piston sealing gasket. The fixed water One end of the tube 8 is connected to a water pump 33 through a water pipe. When cleaning impurities in the electromagnetic valve body 30, the water pump 33 is first powered on to work. The water pump 33 transports external water or organic solvents to the fixed water pipe 8 through the water pipe, and then transports them to the first connecting pipe 24 and the second connecting pipe 36 in sequence through the hollow cavity of the second movable rod 11. The water or organic solvent in the first connecting pipe 24 and the second connecting pipe 36 is transported to the two annular water bags 20 through a plurality of second fixed hollow pipes 23. As the water pressure in the two annular water bags 20 gradually increases, the volume of the annular water bags 20 also expands. During the expansion process, due to the limitation of the inner wall of the valve core block 18, the two annular water bags 20 can only move toward the two symmetrical sides of the valve core block 18. After the bag 20 expands, it pushes two push plates 21 respectively, one of which moves along the surface of the second movable rod 11, and the two push plates 21 respectively drive multiple first fixed hollow pipe fittings 22 to move, and the multiple first fixed hollow pipe fittings 22 push the multiple mounting blocks 17 to move out of the stepped hole 34. In the process that the water pressure in the two annular water bags 20 reaches the maximum value, the water or organic solvent in the two annular water bags 20 flows from the multiple first fixed hollow pipe fittings 22 into the mounting groove 29, and the water or organic solvent in the mounting groove 29 flows from the first flow channel 26 into the first nozzle 27. After the water or organic solvent in the first nozzle 27 reaches a certain water pressure, it can be sprayed from it to the inner surface of the solenoid valve body 30 to flush impurities attached to the inner surface of the solenoid valve body 30.

[0028] The second movable rod 11 and the two annular water bags 20 are fixed by a movable connection mechanism, which includes a first connecting tube 24 and a second connecting tube 36. A fixed hollow pipe 25 is welded to one end of the first connecting tube 24. One end of the fixed hollow pipe 25 extends to the inside of the second connecting tube 36. The fixed hollow pipe 25 and the second connecting tube 36 are sealed and connected by a piston seal. One end of the second connecting tube 36 is welded to the end of the second movable rod 11. A plurality of second fixed hollow pipes 23 are installed on the surfaces of the first connecting tube 24 and the second connecting tube 36. One end of the plurality of second fixed hollow pipes 23 is divided into The plurality of second fixed hollow pipe fittings 23 are respectively installed through the surfaces of the two annular water bags 20. After the two annular water bags 20 expand due to the increase of water pressure in the two annular water bags 20, the plurality of second fixed hollow pipe fittings 23 are displaced synchronously with the expansion of the two annular water bags 20. The plurality of second fixed hollow pipe fittings 23 apply external forces to the first connecting pipe 24 and the second connecting pipe 36 respectively. After the second connecting pipe 36 is subjected to the force, it slides on the surface of the fixed hollow pipe fitting 25. After the first connecting pipe 24 is subjected to the force, it drives the fixed hollow pipe fitting 25 to slide in the second connecting pipe 36, which facilitates the stable transportation of water or organic solvents to the two annular water bags 20 through the second movable rod 11 after the two annular water bags 20 expand.

[0029] A plurality of second flow channels 35 connected to the mounting grooves 29 are provided inside the mounting block 17, and a plurality of second nozzles 28 connected to the second flow channels 35 are embedded on the side of the mounting block 17. The second nozzles 28 are arranged obliquely. The second flow channels 35 can provide flow of water or organic solvents, and the water or organic solvents in the second flow channels 35 are sprayed out from the second nozzles 28. The second nozzles 28 spray the water or organic solvents onto the side of the valve core block 18, so as to facilitate cleaning of impurities on the surface of the valve core block 18.

[0030] A first mounting sleeve 7 is sleeved between the surfaces of the moving iron core 14 and the fixed iron core 15. One end of the first mounting sleeve 7 is installed on the outside of the solenoid valve body 30. The electromagnetic coil 12 is sleeved on the outside of the first mounting sleeve 7. One end of the second movable rod 11 passes through the surface of the first mounting sleeve 7 and extends to its outside. The first mounting sleeve 7 protects the moving iron core 14 and the fixed iron core 15.

[0031] A tension spring 13 is installed on the inner surface of the first mounting sleeve 7, and one end of the tension spring 13 is installed on the surface of the moving iron core 14. When the two electromagnetic coils 12 are energized in sequence, the moving iron core 14 is forced to move, and the tension spring 13 is stretched by the external force of the moving iron core 14. When the two electromagnetic coils 12 are not energized, the moving iron core 14 is not affected by the external force. The tension spring 13 pulls the moving iron core 14 in the opposite direction through its own elastic potential energy, which facilitates the resetting operation of the moving iron core 14.

[0032] A second mounting sleeve 32 is provided around the electromagnetic coil 12, and one end of the second mounting sleeve 32 is installed outside the electromagnetic valve body 30. The second mounting sleeve 32 protects the electromagnetic coil 12. A wire hole is opened on the surface of the second mounting sleeve 32 to allow the wire to be connected to the electromagnetic coil 12.

[0033] Working principle of cleaning impurities inside the solenoid valve of the pressure dividing valve 3: When cleaning impurities attached to the inside of the solenoid valve body, the present solution requires first removing the pipes connected to the air inlet 31, the first air outlet 9 and the second air outlet 10, and then controlling the water pump 33 to work, and the water pump 33 is in water or an organic solvent or connected to water or an organic solvent through a pipe, and the water pump 33 transports the water or organic solvent to the two annular water bags 20, and after the two annular water bags 20 are expanded, the first nozzle 27 is removed from the stepped hole 34, and at the same time, the water or organic solvent in the two annular water bags 20 is injected synchronously, so that the water or organic solvent in the two annular water bags 20 is The solvent is sprayed out from the multiple first nozzles 27 through the multiple first fixed hollow pipes 22, and the two electromagnetic coils 12 are charged in turn, which is convenient for driving the valve core 18 to move back and forth in the electromagnetic valve body 30. At the same time, the valve core 18 drives the multiple first nozzles 27 to move back and forth synchronously in the electromagnetic valve body 30, which is used to increase the cleaning range of the first nozzle 27 and improve the effect of cleaning impurities inside the electromagnetic valve body 30. The impurities flow out from the air inlet 31, the first air outlet 9 and the second air outlet 10 along with the water or organic solvent, and a container such as a bucket or a box is set below the solenoid valve to receive the water or organic solvent falling from the solenoid valve.

[0034] The above-mentioned gas chromatography continuous sampling device and its application in the rapid screening of specific targets specifically include the following operating steps: S1, start-up balance: start the machine, control system 4 works, control valve core block 18 to close first gas outlet 9, the inlet of sampler 37 is connected to the inlet 31 of pressure divider valve 3 through damping column 2, and forms a passage with second gas outlet 10, second gas outlet 10 is connected to chromatographic column 38, chromatographic column 38 is connected to detector 39, and the balancing instrument is started; S2, setting time: setting the connection time between the air inlet 31 of the pressure dividing valve and the second air outlet (10) to C1, C2, C3 ... Cn through the display controller 5, where n is the number of injections; setting the emptying time between the air inlet 31 of the pressure dividing valve 3 and the first air outlet 9 to E1, E2, E3 ... En, where n is the number of injections; S3, pressure-dividing valve emptying: the control system 4 works, and after the time reaches the input condition time E1, E2, E3 ... En, the valve core block 18 closes the second gas outlet 10; the pressure-dividing valve inlet 31 and the first gas outlet 9 form a passage, and the first gas outlet 9 is connected to the emptying pipe 6, and the emptying operation is performed; S4, pressure-dividing valve injection: the control system 4 works, and when the time reaches the input condition time C1, C2, C3 ... Cn, the valve core block 18 closes the first gas outlet 9, the pressure-dividing valve gas inlet 31 is connected with the second gas outlet 10, the second gas outlet 10 is connected with the chromatographic column 38, and is connected with the detector 39, and the injection detection operation is performed; S5, shutdown operation: after completing the continuous sampling test of this batch, the control system 4 controls the valve core block 18 to close the first gas outlet 9 to prevent external pollution from entering the valve body of the pressure dividing valve 3 from the exhaust pipe passage to cause pollution, and shuts down the operation.

[0035] Example 2 Application of Gas Chromatography Continuous Sampling Device in Rapid Screening of Diazinon Target compound: Diazinon 100 ppb.

[0036] (1) The construction and application of the GC-FPD-continuous sampling device platform of this embodiment are the same as those of Example 1.

[0037] (2) Single injection test: Instrument: Gas chromatography-nitrogen phosphorus detector (GC-FPD); Vaporization chamber temperature: 250℃; Injection volume: 2 µL; Chromatographic column: DB-5 MS (30m×0.25mm×0.25µm); Temperature: Constant 110°C.

[0038] The gas chromatogram of single injection detection of diazinon is attached. Fig.10 .

[0039] (3) Continuous sampling detection: Solvent peak retention time: 0-0.1 min; Continuous injection frequency: 3 times, each with an interval of 105 seconds (1.75 min); Solvent peak emptying time: 1.75~1.85 min, 3.5~3.6 min, emptying twice in total.

[0040] The gas chromatogram of continuous injection detection of diazinon is attached. Fig.11 .

[0041] From the results in the attached figure, we can see that: taking 3 samples as an example, the detection time of a single sample is 20 minutes (including instrument equilibration time), and 3 samples take 60 minutes. Continuous injection can shorten the time to 24 minutes (20+1.75×2=23.5 min), which can greatly improve the detection efficiency.

[0042] Example 3 Application of Gas Chromatography Continuous Sampling Device in Rapid Screening of Propylene Bromide Target compound: Profenofos 200 ppb.

[0043] (1) The construction and application of the GC-FPD-continuous sampling device platform of this embodiment are the same as those of Example 1.

[0044] (2) Single injection test: Instrument: Gas chromatography-nitrogen phosphorus detector (GC-FPD); Vaporization chamber temperature: 250℃; Injection volume: 2 µL; Chromatographic column: DB-5 MS (30m×0.25mm×0.25µm); Temperature: Constant 120°C.

[0045] The gas chromatogram of single injection detection of propyl bromide is attached Fig.12 .

[0046] (3) Continuous sampling detection: Solvent peak retention time: 0-0.1 min; Continuous injection frequency: 3 times, each with an interval of 100 seconds (1.7 min); Solvent peak emptying time: 1.7~1.8 min, 3.4~3.5 min, emptying twice in total.

[0047] See the attached gas chromatogram for continuous sampling detection of propyl bromide Fig.13 .

[0048] From the results in the attached figure, we can see that: taking 3 samples as an example, the single sample detection time is 19 minutes (including instrument equilibration time), and 3 samples take 57 minutes. Continuous injection can shorten the time to 23 minutes (19+1.7×2=22.4 min), which can greatly improve the detection efficiency.

[0049] Example 4 Application of Gas Chromatography Continuous Sampling Device in Rapid Screening of Phosalone Target compound: Phosalone 200 ppb.

[0050] (1) The construction and application of the GC-FPD-continuous sampling device platform of this embodiment are the same as those of Example 1.

[0051] (2) Single injection test: Instrument: Gas chromatography-nitrogen phosphorus detector (GC-FPD); Vaporization chamber temperature: 250℃; Injection volume: 2 µL; Chromatographic column: DB-5 MS (30m×0.25mm×0.25µm); Temperature: Constant 130°C.

[0052] The gas chromatogram of single injection detection of phosalone is attached. Fig.14 .

[0053] (3) Continuous sampling detection: Solvent peak retention time: 0-0.1 min; Continuous injection frequency: 3 times, each with an interval of 105 seconds (1.75 min); Solvent peak emptying time: 1.75~1.85 min, 3.5~3.6 min, emptying twice in total.

[0054] The gas chromatogram of phosalone continuous sampling detection is attached. Fig.15 .

[0055] From the results in the attached figure, we can see that: taking 3 samples as an example, the detection time of a single sample is 20 minutes (including instrument equilibration time), and 3 samples take 60 minutes. Continuous injection can shorten the time to 24 minutes (20+1.75×2=23.5 min), which can greatly improve the detection efficiency.

[0056] Example 5 Application of Gas Chromatography Continuous Sampling Device in Rapid Screening of Methyl Nonanoate Target compound: Methyl nonanoate 1 ppm, 2.5 ppm, 5 ppm.

[0057] (1) Construction of GC-MS continuous sampling device platform: The sample injector and the chromatographic column are connected by the gas chromatography continuous sampling device of the present invention. Specifically, the sample inlet of the sample injector 37 is connected to the air inlet 31 of the pressure divider valve through the damping column, and is connected to the chromatographic column 38 through the second air outlet 10. The chromatographic column 38 is connected to the MS detector 39.

[0058] (2) Single injection test: Instrument: Gas chromatography-mass spectrometry (GC-MS); Vaporization chamber temperature: 250℃; Injection volume: 2 µL; Chromatographic column: CP Sil-88 (100m×0.25mm×0.20µm); Temperature: Constant 160°C.

[0059] The total ion current of the solvent peak detected by single injection of methyl nonanoate is shown in the attached figure. Fig.16 .

[0060] (3) Continuous sampling detection: Determine the solvent peak retention time: 10.1-10.4 min; Continuous injection frequency: 3 times, each with an interval of 150 seconds (2.5 min); Solvent peak emptying time: 12.6-12.9 min, 15.1-15.4 min, 2 times in total; In the selected ion mode, the characteristic ions m / z=74, 87, and 129 of methyl nonanoate were scanned as qualitative basis. The mass spectrum of the continuous injection detection standard of methyl nonanoate is attached. Fig.17 , Selected ion current diagram is attached Fig.18 .

[0061] From the results in the attached figure, we can see that: taking 3 samples as an example, the single sample detection time is 90 minutes (including instrument equilibration time), and 20 samples take 270 minutes. Continuous injection can shorten the time to 95 minutes (90+2.5×2=95 min), which can greatly improve the detection efficiency.

[0062] In summary, the gas chromatography continuous sampling device of the present invention empties the fraction through the pressure-dividing valve to remove the solvent peak, ensures that the solvent and the target compound can be separated at the damping column baseline, overcomes the problem that continuous sampling will cause a pulsed solvent peak, reduces the influence of covering or flattening the peak of the target compound in the front section, and thus realizes the continuous supply and analysis of samples without interrupting chromatographic separation. It greatly saves the detection time of continuous sampling, realizes rapid and accurate detection of large batches of samples, and improves the detection efficiency.

[0063] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A gas chromatography continuous sampling device, characterized in that: The invention comprises a housing (1), a damping column (2), a pressure dividing valve (3), a control system (4) and a display controller (5), wherein the damping column (2) and the pressure dividing valve (3) are installed inside the housing (1); the front end of the damping column (2) is connected to the outlet of the vaporization chamber, and the rear end thereof is connected to the air inlet (31) of the pressure dividing valve (3), so as to function as a channel connecting the vaporization chamber and the pressure dividing valve, and to achieve pre-separation of the solvent and the target compound; the pressure dividing valve (3) is a multi-channel valve capable of switching the fluid paths between the channels, and is capable of exhausting the fraction within a predetermined time period, so as to achieve removal of the solvent peak; the pressure dividing valve (3) is provided with a first air outlet (9) and a second air outlet (10), the first air outlet (9) of the pressure dividing valve (3) is connected to an exhaust pipe (6) via a pipeline, so as to exhaust the exhausted gas; the second air outlet (10) of the pressure dividing valve (3) is connected to a chromatographic column (38) via a pipeline; the pressure dividing valve (3), the control system (4) and the display controller (5) are electrically connected via a control circuit.

2. A gas chromatography continuous sampling device as claimed in claim 1, characterized in that: The pressure dividing valve (3) comprises an electromagnetic valve body (30), the surface of which is respectively provided with an air inlet (31), a first air outlet (9) and a second air outlet (10), a valve core block (18) being matched and mounted inside the electromagnetic valve body (30), two symmetrical side surfaces of which are respectively provided with a second movable rod (11) and a first movable rod (16), one end of which penetrates the surface of the electromagnetic valve body (30) and extends to the outside thereof, a fixed iron core (15) is movably sleeved on the surface of the second movable rod (11) and the first movable rod (16), the fixed iron core (15) being mounted on the outside of the electromagnetic valve body (30), one end of which is both fixedly sleeved with a moving iron core (14), the positions of the moving iron core (14) and the fixed iron core (15) corresponding to each other, and an electromagnetic coil (12) is sleeved around the moving iron core (14) and the fixed iron core (15).

3. A gas chromatography continuous sampling device as claimed in claim 2, characterized in that: The valve core block (18) is a hollow structure. Two annular water bags (20) are arranged inside the valve core block (18). A push plate (21) is bonded to the surface of the annular water bag (20). A plurality of first fixed hollow pipes (22) are installed through the surface of the push plate (21). A compression spring (19) is sleeved on the surface of the first fixed hollow pipe (22). The two ends of the compression spring (19) are respectively installed on the surfaces of the valve core block (18) and the push plate (21). One end of each of the plurality of first fixed hollow pipes (22) is installed through the surface of the annular water bag (20). The two symmetric parts of the valve core block (18) are each provided with a plurality of stepped holes (34) corresponding to the positions of the first fixed hollow pipes (22). The inside of each of the stepped holes (34) is matched with a mounting block (17). A mounting groove (29) is provided on the side of the mounting block (17). The first fixed hollow pipe (2 2) extends to the inside of the mounting groove (29), the surface of the mounting block (17) is provided with a first flow channel (26) connected to the mounting groove (29), the internal thread of the first flow channel (26) is provided with a first nozzle (27), the positions of the first nozzle (27) and the inner surface of the electromagnetic valve body (30) correspond to each other, the second movable rod (11) is a hollow structure, the other end of the second movable rod (11) passes through the side of the valve core block (18) and the side of the push plate (21) in sequence and extends to the inner hole of the annular water bag (20), one end of the second movable rod (11) extends to one side of the moving iron core (14), one end of the second movable rod (11) is provided with a fixed water pipe (8) through a piston sealing gasket, one end of the fixed water pipe (8) is connected to a water pump (33) through a water pipe, and the second movable rod (11) and the two annular water bags (20) are fixed by a movable connection mechanism.

4. A gas chromatography continuous sampling device as claimed in claim 3, characterized in that: The movable connection mechanism comprises a first connecting tube (24) and a second connecting tube (36); a fixed hollow tube (25) is welded to one end of the first connecting tube (24); one end of the fixed hollow tube (25) extends to the interior of the second connecting tube (36); the fixed hollow tube (25) and the second connecting tube (36) are sealed and connected via a piston seal; one end of the second connecting tube (36) is welded to the end of the second movable rod (11); a plurality of second fixed hollow tubes (23) are installed through the surfaces of the first connecting tube (24) and the second connecting tube (36); one end of the plurality of second fixed hollow tubes (23) are installed through the surfaces of the two annular water bags (20), respectively.

5. A gas chromatography continuous sampling device as claimed in claim 3, characterized in that: A plurality of second flow channels (35) communicating with the installation grooves (29) are provided inside the installation block (17), and a plurality of second nozzles (28) communicating with the second flow channels (35) are embedded on the side surface of the installation block (17), wherein the second nozzles (28) are arranged obliquely.

6. A gas chromatography continuous sampling device as claimed in claim 3, characterized in that: The liquid injected into the annular water bag (20) for cleaning is water or an organic solvent.

7. A gas chromatography continuous sampling device as claimed in claim 2, characterized in that: A first mounting sleeve (7) is sleeved between the surfaces of the movable iron core (14) and the fixed iron core (15); one end of the first mounting sleeve (7) is mounted on the outside of the electromagnetic valve body (30); the electromagnetic coil (12) is sleeved on the outside of the first mounting sleeve (7); and one end of the second movable rod (11) penetrates the surface of the first mounting sleeve (7) and extends to the outside thereof.

8. A gas chromatography continuous sampling device as claimed in claim 7, characterized in that: A tension spring (13) is mounted on the inner surface of the first mounting sleeve (7), and one end of the tension spring (13) is mounted on the surface of the moving iron core (14).

9. A gas chromatography continuous sampling device as claimed in claim 2, characterized in that: A second mounting sleeve (32) is provided around the electromagnetic coil (12), and one end of the second mounting sleeve (32) is mounted outside the electromagnetic valve body (30).

10. An application of the gas chromatography continuous sampling device as claimed in claim 1 in rapid screening of specific targets, characterized in that The steps are as follows: S1, start-up balancing: start the machine, control the control system (4) to operate, control the valve core block (18) to close the first gas outlet (9), the sample inlet of the sampler (37) is connected to the gas inlet (31) of the pressure dividing valve (3) through the damping column (2), and a passage is formed with the second gas outlet (10), the second gas outlet (10) is connected to the chromatographic column (38), the chromatographic column (38) is connected to the detector (39), and the balancing instrument is started; S2, setting time: setting the communication time between the air inlet (31) and the second air outlet (10) of the pressure dividing valve to C1, C2, C3, ... Cn through the display controller (5), wherein n is the number of injections; setting the emptying time between the air inlet (31) and the first air outlet (9) of the pressure dividing valve (3) to E1, E2, E3, ... En, wherein n is the number of injections; S3, pressure-dividing valve emptying: the control system (4) works, and after the time reaches the input conditions of time E1, E2, E3, ... En, the valve core block (18) closes the second air outlet (10); the pressure-dividing valve air inlet (31) and the first air outlet (9) form a passage, and the first air outlet (9) is connected to the emptying pipe (6), and the emptying operation is performed; S4, pressure divider valve injection: the control system (4) works, and when the time reaches the input condition time C1, C2, C3 ... Cn, the valve core block (18) closes the first gas outlet (9), the pressure divider valve gas inlet (31) is connected to the second gas outlet (10), the second gas outlet (10) is connected to the chromatographic column (38), and is connected to the detector (39), and the injection detection operation is performed; S5, shutdown operation: After completing the continuous sampling test of this batch, the control system (4) controls the valve core block (18) to close the first gas outlet (9) to prevent external pollution from entering the valve body of the pressure dividing valve (3) through the exhaust pipe passage and causing pollution, and then shuts down the operation.

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