Graphite furnace atomizer sulfate shield pre-assembly and method of use

Abstract

The present application relates to a graphite furnace atomizer sulfate shielding pre-device, which comprises a sample inlet tube connected with a sample peristaltic pump at one end for inputting sample, and in parallel with a dilute nitric acid inlet tube and a barium nitrate inlet tube at the other end, respectively supplied by the peristaltic pump. After parallel convergence, the liquid enters a first cyclone mixing chamber to complete the sample mixing and acidification. The liquid enters a second cyclone mixing chamber through the bottom communication pipe and reacts with barium nitrate to generate barium sulfate precipitate. The mixed liquid flows into the collection area through the inverted umbrella-shaped distributor and the rotary reaction generator, and when flowing through the narrow pipeline, the photoelectric sensor monitors the content of the precipitate. After the liquid enters the precipitation area, it is discharged through the discharge valve plate. The three-way electromagnetic valve adjusts the flow direction according to the detection result, and completes the switching of sample inlet or waste liquid delivery. The device has high integration and simple operation, and is suitable for the efficient and accurate requirements of modern analytical chemistry, especially in trace analysis, which can significantly improve the working stability and safety of the graphite furnace atomizer.

Description

Technical Field

[0001] This invention belongs to the field of environmental monitoring technology, and specifically relates to a sulfate shielding pre-processor for a graphite furnace atomizer and its usage method. Background Technology

[0002] Currently, graphite furnace atomizers (FFAs), as an important component of non-flame atomizers, have been widely used in trace element analysis, especially in resource and environmental detection, since their first application in atomic absorption spectrometry by Soviet physicist G.B. Lviv in 1959. Due to their high atomization efficiency and sensitivity, they are particularly valuable for this purpose. However, when atomizing samples using FFAs, samples containing sulfate ions are frequently encountered. Sulfate ions readily react with the graphite in the graphite tube at high temperatures, producing carbon dioxide, sulfur dioxide, and water vapor. With the widespread adoption of automated sample introduction equipment and the growing trend towards unmanned laboratories, the immediate reaction of sulfate ions entering the graphite tube not only leads to the gradual consumption of the tube but also increases the risk of ablation and perforation. This can range from affecting instrument accuracy and precision to causing instrument damage or even fire hazards. While laboratories currently try to prevent sulfate ions from entering the graphite furnace by strictly controlling the composition of the introduced samples, sulfate ions are ubiquitous in various samples and cannot be completely avoided, leading to a faster replacement frequency of graphite tubes. Furthermore, as graphite tubes are custom-made consumables, their replacement costs are high. Each time a graphite tube is replaced, all samples need to be re-measured, resulting in lower instrument analysis efficiency and higher maintenance costs.

[0003] Currently, the commonly used detection methods for sulfate ions include gravimetric method, turbidimetric method, colorimetric method, or ion chromatography. The principle of gravimetric determination of sulfate is that under slightly acidic conditions, Ba2+ reacts with SO42- to form barium sulfate precipitate. After drying, the precipitate is measured. This method is suitable for environments with high sulfate concentrations, but the determination requires sample separation, drying, and weighing. This method cannot be used for continuous sample measurement in analytical instruments. The barium chromate colorimetric method involves adding a barium chromate suspension to a water sample under slightly acidic conditions, generating barium sulfate precipitate and releasing chromate. After neutralization, excess barium chromate and the generated barium sulfate remain in a precipitate state, which is removed by filtration. Under alkaline conditions, chromate appears yellow and can be measured using a spectrophotometer. This method introduces other ions and requires precipitate separation. Ion chromatography is sensitive and suitable for clean water samples, and can simultaneously measure multiple other anions. However, the measurement time is relatively long, and the column separation time for sulfate is approximately 30 minutes, which cannot meet the needs of rapid determination. The turbidimetric method involves directly adding a certain amount of barium chloride-hydrochloric acid solution to the sample. If the solution contains sulfate, barium sulfate precipitate will be generated, causing a change in the turbidity of the test solution. It has advantages such as rapid response and a wide detection range. The above methods all require individual measurement of the tested samples, are mostly based on basic chemical tests, have relatively large sample requirements, high detection risk but poor sensitivity, complex testing operations, bulky and poorly integrated testing equipment, and long measurement times. Furthermore, the determination and pretreatment techniques for sulfate are still at the traditional titration testing stage. This is inconsistent with the characteristics of modern analytical chemistry, which emphasizes speed, accuracy, and the determination of trace samples. In practice, large instruments often require hundreds or thousands of samples, and the sample volume is limited, making it impractical to perform macrochemical titration tests on each sample individually. Therefore, there is an urgent need for a pre-sample preparation device that can detect sulfate online, has a certain sulfate shielding function, and automatically interrupts the sample injection when excess sulfate is present. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing a sulfate shielding pre-treatment device for a graphite furnace atomizer. The specific technical solution is as follows:

[0005] This invention provides a sulfate shielding pre-treatment device for a graphite furnace atomizer. The device includes: a sample inlet tube with a sample peristaltic pump at one end for sample input and a dilute nitric acid inlet tube connected in parallel at the other end, through which dilute nitric acid is supplied by the peristaltic pump; and a separate barium nitrate inlet tube for barium nitrate input. The parallel tubes merge and connect to a spherical first vortex mixing chamber. Symmetrically positioned behind the first vortex mixing chamber is a spherical second vortex mixing chamber, with a hollow bottom connecting pipe penetrating its connection point. This connecting pipe is connected in series with the barium nitrate inlet tube. The second vortex mixing chamber is connected in series with an inverted umbrella-shaped diffuser and a cylindrical rotary reactor. The inner wall of the rotary reactor is embedded with an oblique turbulence ring that circulates along the sample... The flow path is connected to a lotus-shaped collection area. A narrow pipe extends from the outlet of this collection area, with a photoelectric transmitter and a vertically corresponding photoelectric sensor receiver sandwiched between its upper and lower ends for real-time monitoring of the precipitate content (turbidity of the pretreated sample). The narrow pipe is connected in series to a lotus-shaped sedimentation area. Vertical sedimentation discharge pipes are branched downwards from the bottom of this sedimentation area. A discharge valve plate with a rubidium magnet attached is embedded at the junction of the sedimentation discharge pipes. A polytetrafluoroethylene O-ring is pressed under the valve plate, and an electromagnet is attached to the outer surface of the sedimentation discharge pipe for energizing and adjusting the rubidium magnet to open and close the discharge valve plate. A three-way solenoid valve is connected to the sedimentation area along the fluid direction, which adjusts the fluid direction of the graphite furnace feed pipe and the waste liquid discharge pipe according to the photoelectric detection results.

[0006] As a preferred technical solution of the present invention, the device is provided with a cleaning pipe, one end of which is equipped with a hot EDTA solution pump, and the other end is connected in parallel with the injection tube, in order to avoid the influence of residual liquid in the pipe on subsequent operations.

[0007] First, once the photoelectric transmitter and photoelectric sensor receiver detect the presence of excess sulfate ions in the sample, the hot EDTA solution pump is immediately activated, pumping 10 mL of EDTA solution into the pipeline to complete the initial cleaning of the pipeline. Subsequently, the dilute nitric acid peristaltic pump pumps 5 mL of dilute nitric acid into the pipeline for a secondary acid wash to complete the sulfate shielding operation. Next, the three-way solenoid valve and electromagnet are energized to completely discharge the cleaning waste liquid. Finally, the pipeline returns to its initial sample injection state.

[0008] As a preferred embodiment of the present invention, the pipe portion is composed of polytetrafluoroethylene.

[0009] As a preferred embodiment of the present invention, the diffuser and the rotary reaction generator are manufactured by photosensitive 3D printing, and the materials are reinforced SLA resin and weakly alkaline curing agent.

[0010] As a preferred embodiment of the present invention, the pipe interface is provided with multiple inspection ports, which are fixed by bolts and sealed with polytetrafluoroethylene O-rings.

[0011] As a preferred embodiment of the present invention, the temperature of the EDTA solution is 75°C.

[0012] As a preferred embodiment of the present invention, the volume ratio of the dilute nitric acid is 5%.

[0013] As a preferred embodiment of the present invention, the base of the barium nitrate solution is 5% dilute nitric acid, and the mass ratio is 5%.

[0014] This invention also discloses a method for using a sulfate-shielding pre-treatment device for a graphite furnace atomizer. 100 μL of a sulfate-containing sample, delivered via a sample peristaltic pump and inlet tube, is combined with 20 μL of dilute nitric acid, introduced via a dilute nitric acid peristaltic pump and inlet tube, and enters the first vortex mixing chamber. In the first vortex mixing chamber, the sample is thoroughly mixed and acidified. The mixed liquid then enters the second vortex mixing chamber through a connecting tube at the bottom of the mixing chamber, where it reacts fully with 50 μL of barium ions introduced via a barium nitrate peristaltic pump and inlet tube to generate barium sulfate precipitate. The mixture then sequentially passes through a distributor and a rotary reactor, with obliquely arranged turbulence rings aiding in thorough mixing to form a pretreatment solution. As the pretreatment solution flows through the collection zone, the fluid channel gradually narrows, causing the flow rate to gradually increase. The flow rate reaches its maximum when passing through the pipe section directly opposite the photoelectric transmitter and photoelectric sensor receiver, simultaneously measuring the barium sulfate precipitate. The fluid then enters the sedimentation zone, where the flow rate slows down and the residence time is prolonged, allowing the barium sulfate precipitate to fully settle. Once the sedimentation process is complete, the three-way solenoid valve switches the channel from the sample inlet-graphite atomizer to the sample inlet-waste discharge pipe. The sample peristaltic pump and the dilute nitric acid peristaltic pump immediately stop operating. At this point, the electromagnet is energized, controlling the rubidium magnet on the discharge valve plate. The discharge valve plate opens, allowing the barium sulfate precipitate to be discharged from the system through the sedimentation discharge pipe and the waste pipe. After discharge, the solenoid valve is de-energized, and the rubidium magnet is reset, causing the discharge valve plate to close, completing the entire processing procedure.

[0015] As a preferred embodiment of the present invention, the rotary reactor is equipped with multiple obliquely spirally arranged turbulence rings, with the spacing increasing linearly along the fluid flow direction, which is used to accelerate the flow rate of the fluid and promote the reaction.

[0016] As a preferred embodiment of the present invention, the device is mounted on a machine base.

[0017] The beneficial effects of this invention are:

[0018] This graphite furnace atomizer sulfate shielding pretreatment device achieves effective shielding and pretreatment of sulfate ions through a series of process steps, yielding significant benefits. First, the device ensures precise mixing of the sample and dilute nitric acid through parallel flow of a sample peristaltic pump and a dilute nitric acid peristaltic pump, completing acidification in the first vortex mixing chamber. This process ensures that sulfate ions are fully released and react effectively in subsequent treatments. Second, barium ions are introduced into the second vortex mixing chamber through a series-connected barium nitrate inlet pipe, reacting fully with the sulfate ions in the sample to generate barium sulfate precipitate. This process is optimized within the device's built-in rotary reactor; the obliquely arranged turbulence rings effectively improve the reaction efficiency of the mixture, resulting in a more uniform formation of barium sulfate precipitate.

[0019] The device further monitors the precipitate content in the fluid in real time using a photoelectric transmitter and a photoelectric sensor receiver to ensure the stability and accuracy of the precipitation process. When the amount of precipitate generated reaches a certain threshold, the system can automatically determine that the reaction is complete and adjust the channel of the three-way solenoid valve through the electronic control system. This achieves automatic switching between the sample inlet and waste liquid discharge pipes, preventing uncleaned samples from entering the graphite furnace atomizer and preventing graphite tube damage or even safety accidents caused by sulfate residue. In addition, the design of the precipitation zone slows down the fluid flow rate, providing sufficient time for the precipitate to settle fully, avoiding precipitate loss or accumulation.

[0020] By precisely controlling the discharge valve plate with an electromagnet, precipitates can be discharged from the system in a timely manner, ensuring the waste discharge function of the device, effectively extending its service life, and reducing maintenance workload. This design not only reduces the wear and tear of sulfate on the graphite tubes and lowers experimental costs, but also improves the operational safety of the laboratory and the analytical efficiency of the instrument. Overall, the device is highly integrated and easy to operate, suitable for the high-efficiency and precise requirements of modern analytical chemistry, especially in the field of trace analysis, where it can significantly improve the operational stability and safety of graphite furnace atomizers. Attached Figure Description

[0021] Figure 1 A schematic diagram of the overall structure of the present invention is shown;

[0022] Figure 2 A schematic diagram of the process of the present invention is shown;

[0023] Figure 3 A three-dimensional structural schematic diagram of the present invention is shown;

[0024] Figure 4 A front view of the invention is shown;

[0025] Figure 5 A front view of the rotary reaction generator of the present invention is shown;

[0026] Figure 6 A cross-sectional view of the rotary reaction generator of the present invention is shown;

[0027] Figure 7 A three-dimensional structural schematic diagram of the turbulence ring in this invention is shown;

[0028] The diagram shows: 1. Barium nitrate peristaltic pump; 101. Barium nitrate inlet pipe; 2. Hot EDTA solution pump; 201. Cleaning pipe; 3. Dilute nitric acid peristaltic pump; 301. Dilute nitric acid inlet pipe; 4. Sample peristaltic pump; 401. Sample inlet pipe; 5. First vortex mixing chamber; 6. Bottom connecting pipe of mixing chamber; 7. Second vortex mixing chamber; 8. Distributor; 9. Rotary reaction generator; 91. Turbulence ring; 10. Collection area; 11. Photoelectric transmitter; 12. Photoelectric sensor receiver; 13. Rubidium magnet; 14. Discharge valve plate; 15. Electromagnet; 16. PTFE O-ring; 17. Precipitation zone; 18. Precipitation discharge pipe; 19. Three-way solenoid valve; 20. Waste liquid discharge pipe; 21. Graphite furnace feed pipe; 22. Narrow pipe; 23. Inspection port; 24. Machine platform. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0030] Example 1

[0031] To address the technical problems in the background section, the following sulfate shielding pre-treatment device for a graphite furnace atomizer is provided:

[0032] Combination Figure 1-4As shown, the graphite furnace atomizer sulfate shielding pre-treatment device includes: a sample inlet pipe 401, one end of which is equipped with a sample peristaltic pump 4 for sample input, and the other end is connected in parallel to a dilute nitric acid inlet pipe 301, which is supplied with dilute nitric acid by the dilute nitric acid peristaltic pump 3. A separate barium nitrate inlet pipe 101 is also provided for barium nitrate input. The parallel pipes merge and connect to a spherical first vortex mixing chamber 5. Symmetrically positioned behind the first vortex mixing chamber 5 is a spherical second vortex mixing chamber 7, with a hollow bottom connecting pipe 6 penetrating through its connection point. This pipe is connected in series with the barium nitrate inlet pipe 101. The second vortex mixing chamber 7 is connected in series with an inverted umbrella-shaped diffuser 8 and a cylindrical rotary reactor 9. The inner wall of the rotary reactor 9 is embedded with an oblique turbulence ring, and a ring is connected along the sample flow direction. A dome-shaped collection area 10 has a narrow pipe 22 extending from its outlet. A photoelectric transmitter 11 and a vertically corresponding photoelectric sensor receiver 12 are sandwiched between the upper and lower parts of the narrow pipe 22 for real-time monitoring of sediment content. A lotus-shaped sedimentation area 17 is connected in series to the narrow pipe 22. A vertically downward sedimentation discharge pipe 18 is provided at the bottom of the sedimentation area 17. A discharge valve plate 14 with a rubidium magnet 13 is embedded at the junction of the sedimentation discharge pipe 18. A polytetrafluoroethylene O-ring 16 is pressed under the discharge valve plate 14. An electromagnet 15 is attached to the outer surface of the sedimentation discharge pipe 18 for energizing and adjusting the rubidium magnet 13 to open and close the discharge valve plate 14. A three-way solenoid valve 19 is connected to the sedimentation area 17 along the fluid direction, which adjusts the fluid direction of the graphite furnace feed pipe 21 and the waste liquid discharge pipe 20 according to the photoelectric detection results.

[0033] Based on the usage method of the sulfate shielding pre-treatment device for graphite furnace atomizer, during sulfate ion detection, 100 μL of sulfate-containing sample is first delivered by sample peristaltic pump 4 and sample inlet tube 401. This sample is then combined with 20 μL of dilute nitric acid introduced by dilute nitric acid peristaltic pump 3 and dilute nitric acid inlet tube 301 and enters the first vortex mixing chamber 5. In the first vortex mixing chamber 5, the sample is thoroughly mixed and acidified. The mixed liquid then enters the second vortex mixing chamber 7 through a connecting tube at the bottom of the mixing chamber, where it reacts fully with 50 μL of barium ions introduced by barium nitrate peristaltic pump 1 and barium nitrate inlet tube 101 to generate barium sulfate precipitate. Subsequently, the mixture passes sequentially through distributor 8 and rotary reactor 9. An obliquely arranged turbulence ring helps the mixture to fully mix, forming a pretreatment solution. Immediately afterward, as the pretreatment liquid flows through the collection zone 10, the fluid channel gradually narrows, causing the flow rate to gradually increase. The flow rate reaches its maximum when passing through the pipe section directly opposite the photoelectric transmitter 11 and the photoelectric sensor receiver 12, simultaneously determining the barium sulfate precipitate. The fluid then enters the precipitation zone 17, where the flow rate slows and the fluid residence time is extended, allowing the barium sulfate precipitate to fully settle in the precipitation zone 17. Once the precipitation process is complete, the three-way solenoid valve 19 switches the channel from the sample inlet tube 401-graphite atomizer to the sample inlet-waste liquid discharge tube 20. The sample peristaltic pump 4 and the dilute nitric acid peristaltic pump 3 immediately stop working. At this time, the electromagnet 15 is energized, controlling the rubidium magnet 13 on the discharge valve plate 14. The discharge valve plate 14 opens, allowing the barium sulfate precipitate to be discharged from the system through the precipitation discharge tube 18 and the waste liquid tube. After discharge, the solenoid valve is de-energized, and the rubidium magnet 13 is reset, causing the discharge valve plate 14 to close, completing the entire processing procedure.

[0034] Through the aforementioned technical means, this graphite furnace atomizer sulfate shielding pretreatment device achieves effective shielding and pretreatment of sulfate ions through a series of process steps, resulting in significant beneficial effects. First, the device ensures precise mixing of the sample and dilute nitric acid through parallel flow of the sample peristaltic pump 4 and the dilute nitric acid peristaltic pump 3, completing the acidification treatment in the first vortex mixing chamber 5. This process ensures that sulfate ions are fully released and effectively reacted in subsequent treatments. Second, barium ions are introduced into the second vortex mixing chamber 7 through a series-connected barium nitrate inlet pipe 101, where they fully react with the sulfate ions in the sample to generate barium sulfate precipitate. This process is optimized in the device's built-in rotary reactor 9, where the obliquely arranged turbulence rings effectively improve the reaction efficiency of the mixture, resulting in a more uniform formation of barium sulfate precipitate.

[0035] The device further monitors the precipitate content in the fluid in real time through a photoelectric transmitter 11 and a photoelectric sensor receiver 12 to ensure the stability and accuracy of the precipitation process. When the amount of precipitate generated reaches a certain threshold, the system can automatically determine that the reaction is complete and adjust the channel of the three-way solenoid valve 19 through the electronic control system, thereby realizing the automatic switching between the sample inlet and waste liquid discharge pipe 20. This prevents uncleaned samples from entering the graphite furnace atomizer and avoids graphite tube damage or even safety accidents caused by sulfate residue. In addition, the design of the precipitation zone 17 slows down the fluid flow rate, providing sufficient time for the precipitate to settle fully, avoiding precipitate loss or accumulation.

[0036] By precisely controlling the rubidium magnet 13 embedded in the discharge valve plate 14 via the electromagnet 15, precipitates can be discharged from the system in a timely manner, ensuring the waste discharge function of the device, effectively extending its service life, and reducing maintenance workload. This design not only reduces the wear and tear of sulfate on the graphite tube and lowers experimental costs, but also improves the operational safety of the laboratory and the analytical efficiency of the instrument. Overall, the device is highly integrated and easy to operate, suitable for the high-efficiency and precise requirements of modern analytical chemistry, especially in the field of trace analysis, where it can significantly improve the operational stability and safety of graphite furnace atomizers.

[0037] Example 2

[0038] like Figure 2-4 As shown, based on the above embodiments, this embodiment further provides the following:

[0039] In this embodiment, the device is provided with a cleaning pipe 201, one end of which is equipped with a hot EDTA solution pump 2, and the other end is connected in parallel with the sample inlet pipe 401, in order to avoid the influence of residual liquid in the pipe on subsequent operations.

[0040] First, once the photoelectric transmitter 11 and the photoelectric sensor receiver 12 detect the presence of excess sulfate ions in the sample, the hot EDTA solution pump 2 immediately starts, pumping 10 mL of EDTA solution into the pipeline to complete the initial cleaning of the pipeline. Then, the dilute nitric acid peristaltic pump 3 pumps 5 mL of dilute nitric acid into the pipeline for a second acid wash to complete the sulfate shielding operation. Next, the three-way solenoid valve 19 and the electromagnet 15 are energized to completely discharge the cleaning waste liquid. Finally, the pipeline returns to its initial sample injection state.

[0041] Through the aforementioned technical means, the device incorporates a cleaning pipeline 201 and a hot EDTA solution pump 2, further enhancing the system's cleaning efficiency and operational safety, demonstrating significant beneficial effects. By setting up the cleaning pipeline 201, when the photoelectric transmitter 11 and photoelectric sensor receiver 12 detect excess sulfate ions in the sample, the hot EDTA solution pump 2 immediately activates, injecting 10 mL of EDTA solution into the pipeline. This process ensures that residual sulfate ions and other potential interfering substances in the pipeline are rapidly removed, preventing them from affecting subsequent sample analysis. Immediately afterwards, a dilute nitric acid peristaltic pump 3 injects 5 mL of dilute nitric acid for a secondary acid wash, further ensuring the cleanliness of the pipeline and the chemical stability of the system, avoiding sulfate residue and accumulation in the pipeline, and enhancing the sulfate shielding effect.

[0042] Subsequently, by controlling the energization of the three-way solenoid valve 19 and the electromagnet 15, the device can quickly and completely drain the cleaning waste liquid from the system, ensuring no residual liquid remains in the pipeline and fully preparing for the next sample injection. This automated cleaning process not only greatly improves the system's cleaning efficiency but also reduces the need for manual intervention, ensuring the continuity of experiments and the accuracy of data. Overall, this design effectively solves the problem of sulfate residue interfering with the graphite furnace sample injection and analysis process, significantly improving the safety, accuracy, and efficiency of laboratory operations, and meeting the requirements of modern trace analysis equipment for efficient cleaning and automated operation.

[0043] Example 3

[0044] like Figure 2-3 As shown, based on the above embodiments, this embodiment further provides the following:

[0045] In this embodiment, the rotary reaction generator 9 is equipped with multiple obliquely spirally arranged turbulence rings 91, and the spacing between them increases linearly along the fluid flow direction, which is used to accelerate the flow rate of the fluid and promote the reaction.

[0046] The pipe section is made of polytetrafluoroethylene.

[0047] The diffuser 8 and the rotary reaction generator 9 are manufactured by photosensitive 3D printing, and the materials are reinforced SLA resin and weakly alkaline curing agent.

[0048] The pipe interface is provided with multiple inspection ports 23, which are fixed by bolts and sealed with polytetrafluoroethylene O-rings.

[0049] Through the aforementioned technical means, firstly, multiple obliquely spirally arranged turbulent rings 91 are installed inside the rotary reactor 9. This design significantly optimizes the fluid flow state. The arrangement of the turbulent rings 91 effectively breaks the laminar flow state of the fluid, forming a complex turbulent structure. This turbulence not only significantly accelerates the fluid velocity but also enhances the mixing and reaction efficiency within the fluid, thereby promoting chemical reactions. This design makes the fluid flow within the reactor more uniform, avoiding dead zones and excessively slow flow rates, thus improving the overall efficiency and reaction rate of the reactor. In particular, the linearly increasing spacing of the turbulent rings 91 along the fluid flow direction further optimizes the fluid flow trajectory, ensuring thorough mixing and reaction in each region during the reaction process, avoiding problems of insufficient or excessive local reaction. The overall design promotes rapid fluid reaction, is suitable for handling various complex fluids, and enhances the reactor's adaptability.

[0050] Secondly, the piping is constructed from polytetrafluoroethylene (PTFE), a material known for its excellent corrosion resistance and high-temperature resistance in industrial applications. PTFE effectively prevents corrosion from various chemicals, extending the equipment's lifespan. Simultaneously, the smooth surface of PTFE reduces fluid resistance within the pipes, further improving flow rate and transport efficiency. Furthermore, PTFE's excellent heat resistance allows it to withstand high-temperature fluids, making it suitable for high-temperature reaction scenarios, which is particularly important in applications requiring chemical reactions at high temperatures. Therefore, the application of PTFE not only enhances the durability of the equipment but also strengthens its adaptability to complex environments.

[0051] Furthermore, the distributor 8 and the rotary reaction generator 9 are manufactured using photosensitive 3D printing, a process offering extremely high precision and flexibility. Photosensitive 3D printing enables precise shaping based on complex structural designs, ensuring the perfect realization of the detailed designs of the turbulence ring 91 and the distributor 8. This manufacturing process, through the combination of reinforced SLA resin and a weakly alkaline curing agent, enhances the structural strength and durability of the device. SLA resin not only possesses excellent mechanical properties but also resists a certain degree of chemical corrosion, making it suitable for high-intensity, long-term industrial applications. The use of a weakly alkaline curing agent further improves the material's stability, ensuring the device maintains excellent physical properties and a long service life even in complex chemical environments. 3D printing reduces errors and material waste in traditional manufacturing, improving production efficiency and product precision.

[0052] Furthermore, the device features multiple inspection ports 23 at pipe interfaces, a design that significantly enhances maintenance convenience. By placing inspection ports 23 at critical locations on the pipeline, users can easily perform regular inspections, cleaning, or replacement of damaged components, ensuring the long-term stable operation of the device. These inspection ports 23 are secured with bolts and sealed with PTFE O-rings 16, guaranteeing that the pipeline will not leak during operation and further improving the safety and sealing of the equipment. The PTFE O-rings 16, with their excellent corrosion resistance and sealing performance, ensure the sealing effect of the pipeline system during long-term operation, reducing maintenance costs and potential risks caused by leaks.

[0053] Example 4

[0054] like Figure 2-4 As shown, based on the above embodiments, this embodiment further provides the following:

[0055] In this embodiment, the temperature of the EDTA solution is 75°C.

[0056] The volume ratio of the dilute nitric acid is 5%.

[0057] The base of the barium nitrate solution is 5% dilute nitric acid, with a mass ratio of 5%.

[0058] The device is mounted on top of the machine base 24 and is enclosed by a window.

[0059] Using the above techniques, firstly, the EDTA solution at 75℃ possesses high reactivity and dissolving power, enabling it to more effectively complex and remove residual metal ions and sulfate ions from the pipeline, thereby ensuring the cleanliness of the pipeline and preventing residues from interfering with subsequent experiments. The appropriate temperature not only improves cleaning efficiency but also ensures safety and stability during the cleaning process.

[0060] The 5% (v / v) concentration of dilute nitric acid is an optimized choice, providing sufficient acidity to promote the reaction between sulfate ions and barium nitrate in the sample, forming barium sulfate precipitate. Simultaneously, this concentration avoids excessive corrosiveness, reducing damage to equipment materials and thus extending equipment lifespan. The 5% matrix and 5% (v / v) mass ratio of the barium nitrate solution further ensure the stability and thoroughness of the precipitation reaction, optimizing the barium sulfate formation conditions, avoiding potential side reactions and deposition problems within the equipment due to excessive barium ions, and improving the accuracy of experimental data.

[0061] The design of the device being mounted on top of the machine base 24 and enclosed by a partition further enhances the convenience and safety of operation. The top mounting makes operation more intuitive and easier to maintain, reducing the risk of malfunctions caused by improper operation. The partition not only provides physical isolation, preventing liquid splashes or gas leaks during experiments, but also offers some sound and heat insulation, reducing noise and temperature effects on the operating environment and improving the quality of the laboratory's working environment. These design features work together to significantly improve the system's operational efficiency, safety, and long-term stability, ensuring the reliability of experiments and the accuracy of data.

[0062] Working principle and usage process of this invention:

[0063] The operation of the sulfate shielding pre-treatment device for the graphite furnace atomizer begins with sample introduction. First, the sample peristaltic pump 4 introduces 100 μL of a sulfate-containing sample into the system through the sample inlet tube 401. Simultaneously, the dilute nitric acid peristaltic pump 3 introduces 20 μL of dilute nitric acid into the device through the dilute nitric acid inlet tube 301, mixing it with the sample in the first vortex mixing chamber 5, thus acidifying the sample. The acidified sample then flows from the first vortex mixing chamber 5 through the bottom connecting tube into the second vortex mixing chamber 7. At this time, the barium nitrate peristaltic pump 1 introduces 50 μL of barium nitrate solution through the barium nitrate inlet tube 101. Sulfate ions react chemically with barium ions to form barium sulfate precipitate. The mixture flows into the second vortex mixing chamber 7 through the connecting tube, then passes through the inverted umbrella-shaped distributor 8 and the cylindrical rotary reactor 9. The oblique arrangement of the turbulence rings facilitates thorough mixing of the liquid, intensifies the reaction, and further forms the precipitate.

[0064] The mixture then enters the lotus-shaped collection zone 10, where the fluid channel gradually narrows and the flow rate gradually increases. As the fluid passes through the narrow pipe 22 containing the photoelectric transmitter 11 and the photoelectric sensor receiver 12, the photoelectric device detects the barium sulfate precipitate content in the mixture in real time. The liquid then enters the sedimentation zone 17, where the flow rate slows down, allowing the precipitate to settle sufficiently. A sedimentation discharge pipe 18 is located at the bottom of the sedimentation zone 17. When the barium sulfate precipitate exceeds the standard, the discharge valve 14 is opened and closed by energizing the embedded neodymium magnet 13 and the external electromagnet 15. Once the precipitate has fully formed, the electromagnet 15 is energized to attract the neodymium magnet 13, opening the discharge valve 14. The precipitate is discharged from the system through the sedimentation discharge pipe 18. Subsequently, the three-way solenoid valve 19 adjusts the liquid flow direction, discharging the waste liquid into the waste liquid discharge pipe 20, completing the waste discharge. When the barium sulfate precipitate is within acceptable limits, the three-way solenoid valve 19 adjusts the liquid flow direction, discharging the mixture into the feed pipe, completing the feed detection.

[0065] After detection and sediment discharge are completed, the system enters the cleaning process. First, when the photoelectric device detects the presence of sulfate ions in the system, the hot EDTA solution pump 2 starts, injecting 75°C EDTA solution into the system through cleaning pipe 201 for initial cleaning to remove residues from the pipe. Subsequently, the dilute nitric acid peristaltic pump 3 injects 5 mL of dilute nitric acid into the pipe for a second acid wash to further remove residual sulfate ions. After cleaning, the three-way solenoid valve 19 switches the pipe flow direction, and the waste liquid is discharged from the system through waste liquid discharge pipe 20. The electromagnet 15 is de-energized, the neodymium magnet 13 resets, the discharge valve plate 14 closes, and the cleaning process ends.

[0066] The entire apparatus is mounted on top of the machine base 24 and enclosed by a partition window, ensuring convenient daily operation and maintenance for personnel. The partition window design effectively prevents splashes and leaks that may occur during experiments, improving experimental safety. Finally, the pipeline returns to its initial sample injection state, and the apparatus is ready to proceed with the next sample processing cycle.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A sulfate shielding pre-treatment device for a graphite furnace atomizer, characterized in that, include: A sample inlet tube (401) is provided with a sample peristaltic pump (4) at one end for sample input, and a dilute nitric acid inlet tube (301) connected in parallel at the other end, through which dilute nitric acid is supplied by the dilute nitric acid peristaltic pump (3). A barium nitrate inlet pipe (101) is provided for the input of barium nitrate. The parallel pipes are connected to a spherical first vortex mixing chamber (5) after merging. The first vortex mixing chamber (5) has a spherical second vortex mixing chamber (7) symmetrically arranged behind it. A hollow mixing chamber bottom connecting pipe (6) is installed through the connection between the two chambers. It is connected in series with the barium nitrate inlet pipe (101). The second vortex mixing chamber (7) is connected in series with an inverted umbrella-shaped diffuser (8) and a cylindrical rotary reaction generator (9). The inner wall of the rotary reaction generator (9) is embedded with an oblique turbulence ring, and a lotus-shaped collection area (10) is connected along the sample flow direction. The outlet of the collection area (10) is extended with a narrow pipe (22), which is sandwiched with a photoelectric emitter (11) and a vertically corresponding photoelectric sensor receiver (12) for real-time monitoring of precipitate content. The narrow pipe (22) is connected in series with a lotus-shaped sedimentation zone (17). The bottom of the sedimentation zone (17) is provided with a vertically downward sedimentation discharge pipe (18). At the junction of the sedimentation discharge pipe (18), a discharge valve plate (14) with a rubidium magnet (13) is embedded. A polytetrafluoroethylene O-ring (16) is pressed down on it. An electromagnet (15) is attached to the outer surface of the sedimentation discharge pipe (18) for energizing and adjusting the rubidium magnet (13) to open and close the discharge valve plate (14). The sedimentation zone (17) is connected with a three-way solenoid valve (19) along the fluid direction, which adjusts the fluid direction of the graphite furnace feed pipe (21) and the waste liquid discharge pipe (20) according to the photoelectric detection result.

2. The sulfate shielding pre-treatment device for a graphite furnace atomizer according to claim 1, characterized in that: The rotary reactor (9) is equipped with multiple obliquely spirally arranged turbulence rings (91) with the spacing increasing linearly along the fluid flow direction, which are used to accelerate the flow rate of the fluid and promote the reaction.

3. The sulfate shielding pre-treatment device for a graphite furnace atomizer according to claim 1, characterized in that: The device is equipped with a cleaning pipe (201), one end of which is equipped with a hot EDTA solution pump (2), and the other end is connected in parallel with the injection pipe (401) to avoid the influence of residual liquid in the pipe on subsequent operations; The photoelectric transmitter (11) and photoelectric sensor receiver (12) identify the presence of excess sulfate ions in the sample. The hot EDTA solution pump (2) is started immediately to pump EDTA solution into the pipeline to complete the initial cleaning of the pipeline. The dilute nitric acid peristaltic pump (3) pumps dilute nitric acid into the pipeline for secondary acid washing to complete the sulfate shielding operation. The three-way solenoid valve (19) and electromagnet (15) are energized to complete the complete discharge of cleaning waste liquid, and the pipeline returns to the initial sample injection state.

4. The sulfate shielding pre-treatment device for a graphite furnace atomizer according to claim 3, characterized in that: The pipe section is made of polytetrafluoroethylene.

5. The sulfate shielding pre-treatment device for a graphite furnace atomizer according to claim 1, characterized in that: The diffuser (8) and the rotary reaction generator (9) are manufactured by photosensitive 3D printing, and the materials are reinforced SLA resin and strong alkaline curing agent.

6. The sulfate shielding pre-treatment device for a graphite furnace atomizer according to claim 4, characterized in that: The pipe interface is provided with multiple inspection ports (23), which are fixed by bolts and sealed with polytetrafluoroethylene O-rings.

7. The sulfate shielding pre-treatment device for a graphite furnace atomizer according to claim 6, characterized in that: The temperature of the EDTA solution is 75°C.

8. The sulfate shielding pre-treatment device for a graphite furnace atomizer according to claim 7, characterized in that: The volume ratio of the dilute nitric acid is 5%, and the matrix of the barium nitrate solution is 5% dilute nitric acid, with a mass ratio of 5%.

9. The sulfate shielding pre-treatment device for a graphite furnace atomizer according to claim 8, characterized in that: The device is mounted on top of the machine base (24) and is enclosed by a window.

10. The method of using the sulfate shielding pre-processor for a graphite furnace atomizer according to any one of claims 1-9, characterized in that: For sulfate ion detection, the sample containing sulfate is transported by the sample peristaltic pump (4) and the sample inlet tube (401), and then mixed with the dilute nitric acid that enters through the dilute nitric acid peristaltic pump (3) and the dilute nitric acid inlet tube (301) before entering the first vortex mixing chamber (5). The sample is fully mixed and acidified in the first vortex mixing chamber (5). After mixing, the liquid enters the second vortex mixing chamber (7) through the connecting pipe at the bottom of the mixing chamber, and reacts fully with the barium ions introduced by the barium nitrate peristaltic pump (1) and the barium nitrate inlet pipe (101) to generate barium sulfate precipitate; The mixture then passes through the distributor (8) and the rotary reactor (9) in sequence. The obliquely arranged turbulence rings help the mixture to be fully mixed to form a pretreated liquid. When the pretreatment liquid flows through the collection area (10), the fluid channel gradually narrows, causing the fluid velocity to gradually increase. When it passes through the pipe section directly opposite the photoelectric transmitter (11) and the photoelectric sensor receiver (12), the velocity reaches its maximum value, and the barium sulfate precipitate is measured simultaneously. When the fluid enters the sedimentation zone (17), the flow rate slows down and the fluid residence time is prolonged, allowing the barium sulfate precipitate to be fully deposited in the sedimentation zone (17). When the precipitation process is complete, the three-way solenoid valve (19) switches the channel from the sample inlet tube (401)-graphite atomizer to the sample inlet-waste liquid discharge tube (20), and the sample peristaltic pump (4) and the dilute nitric acid peristaltic pump (3) stop working immediately.

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