Automatic sampling and pretreatment system for trace water-soluble metal elements in atmosphere

Abstract

The invention discloses an atmospheric trace water-soluble metal element automatic sampling and pretreatment system, the system comprises an automatic sampling module and a pretreatment module, the automatic sampling module is provided with a gas introduction device, a gas corrosion device and a mixing growth chamber from front to back in sequence, and the mixing growth chamber is connected with the pretreatment module; the gas corrosion device is used for separating particulate matters and gas in a to-be-collected atmospheric sample, and the mixed growth chamber enables the particulate matters to grow and condense in supersaturated water vapor to obtain a primary sample; the pretreatment module comprises a sample enrichment unit and an automatic calibration unit; the sample enrichment unit is used for carrying out enrichment treatment on the primary sample through a bubble remover and a plastic injector; the automatic calibration unit is used for sequentially carrying out acid pickling, water washing, sample dilution and quantitative calibration on the enriched sample to finish the pretreatment process of the sample; according to the system, the sampling efficiency and the data reliability are remarkably improved, the automation degree is high, manual operation is reduced, personal errors are reduced, and the monitoring efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of atmosphere monitoring, and in particular relates to an automatic sampling and pre-processing system for trace water-soluble metal elements in the atmosphere. Background Art

[0002] Metal elements are PM 2.5 One of the important chemical components of PM 2.5 The content of PM2.5 is relatively low, accounting for only about 2% of the total mass, but due to its unique physical and chemical properties and biological toxicity, it may cause significant harm to human health and the ecological environment. Studies have shown that PM2.5 2.5 Water-soluble metal elements in PM2.5 can directly enter the human body through the respiratory tract and induce the production of reactive oxygen species (ROS) in the body. The sharp increase in the concentration of reactive oxygen species can cause oxidative stress damage to human cells, leading to a series of health problems. In addition, atmospheric PM2.5 can directly enter the human body through the respiratory tract and induce the production of reactive oxygen species (ROS) in the body. The rapid increase in the concentration of reactive oxygen species can cause oxidative stress damage to human cells, leading to a series of health problems. 2.5 The water-soluble metal elements in PM2.5 include nutrients such as iron, zinc, and copper, as well as toxic and harmful elements such as lead, cadmium, and arsenic. After these elements enter the surface ecosystem through atmospheric deposition, they will affect the biogeochemical cycle process in the environment. 2.5 Accurate monitoring of water-soluble metal elements is of great significance.

[0003] In some specific industrial production processes or combustion processes, gaseous pollutants containing heavy metals are generated. Compared with heavy metals in particulate matter, the types of gaseous heavy metals are relatively few, and the concentration in the atmosphere is usually low. However, the mercury, thallium, cadmium, lead, arsenic, and chromium contained in gaseous pollutants are highly toxic and pose potential hazards to the environment and human health.

[0004] Currently, PM 2.5 The sampling and analysis of water-soluble metal elements and metal elements in gas mainly rely on manual operations, which have problems such as low sampling efficiency, cumbersome pre-processing process, and unstable data quality. Especially in scenarios that require long-term continuous monitoring, traditional methods are difficult to meet actual needs.

[0005] Therefore, it is necessary to develop a system for water-soluble metals in atmospheric particulate matter and metal elements in gas that can realize automated sampling and standardized pre-processing, which is of great significance to improving monitoring efficiency and data reliability. Summary of the invention

[0006] The purpose of the present invention is to provide a system that can realize the automated sampling and standardized pre-treatment of trace water-soluble metal elements in the atmosphere, so as to improve the monitoring efficiency and data reliability. To achieve the above-mentioned purpose of the invention, the specific technical scheme is as follows: An automatic sampling and pre-processing system for trace water-soluble metal elements in the atmosphere, the system comprising an automatic sampling module and a pre-processing module, the automatic sampling module being provided with: a gas introduction device, a gas dissolver and a mixing growth chamber in sequence from front to back, the mixing growth chamber being connected to the pre-processing module, the pre-processing module comprising: a sample enrichment unit and an automatic calibration unit; Furthermore, the gas introduction device is used to introduce the atmospheric sample to be collected containing particulate matter into the gas dissolver; the gas dissolver is used to separate the particulate matter and gas in the atmospheric sample to be collected, and input the separated particulate matter into the mixed growth chamber; the mixed growth chamber includes a steam generator and an electric refrigeration device, which are used to make the particulate matter grow and condense in supersaturated water vapor to obtain a primary sample containing water-soluble metal elements, and the primary sample is transported to the sample enrichment unit through a pipeline; Furthermore, the sample enrichment unit includes a debubbler and a plastic syringe with a two-way valve; the debubbler is used to remove bubbles in the primary sample to eliminate the bubbles in the primary sample, obtain the sample to be enriched and transfer it to the plastic syringe through the two-way valve; the plastic syringe is used to enrich the sample to be enriched to obtain an enriched sample; the automatic calibration system sequentially performs acid washing, water washing, sample dilution and quantitative calibration on the enriched sample to complete the sample pretreatment process.

[0007] Furthermore, the gas aliquot device comprises: a main body (1), a gas selective permeable membrane (4) arranged in the main body (1), the gas selective permeable membrane (4) dividing the internal space of the main body (1) into an outer absorption liquid channel and an intermediate gas and particle flow path; the main body (1) has an air flow inlet (2) and an air flow outlet (3), the air flow passes through the intermediate gas and particle flow path from top to bottom; the main body (1) also has an absorption liquid inlet (5) and an absorption liquid outlet (6), which are arranged at the upper part and the lower part of the main body (1) respectively, for the circulation and replacement of the absorption liquid, and the main body (1) is columnar; Furthermore, the gas selective permeable membrane (4) can allow gaseous heavy metal components to pass through and be absorbed by the outer absorption liquid, while the particulate matter continues to move along the middle flow path. Different absorption liquids are selected for different metal elements in the gas (for example: acidic potassium permanganate solution absorbs mercury in the gas, dilute nitric acid solution absorbs lead, cadmium, thallium, and chromium in the gas, and hydrochloric acid-ascorbic acid solution absorbs elemental arsenic in the gas. The absorption solution is not limited to this).

[0008] Furthermore, the mixing growth chamber comprises a main cavity (7), the inlet end (8) of the main cavity is connected to the outlet of the gas dissolver, and the other end transports the primary sample to the debubbler of the sample enrichment unit through a pipeline; Furthermore, the steam generator (9) is arranged below the main cavity and includes a pure water heating device for generating water vapor; the interior of the main cavity is constructed of plastic material for achieving full mixing of particles and water vapor, so that the particles grow in the supersaturated water vapor; the electric refrigeration device (10) is arranged at the outlet end of the main cavity for condensing the mixed airflow; the outlet end of the main cavity is a conical structure, the outer periphery of the conical structure is arranged as a breathable cavity (11), and the upper part of the breathable cavity (11) is connected to a mechanical pump interface (12) for connecting a mechanical pump to cooperate with the electric refrigeration device (10) to achieve condensation of the mixed airflow.

[0009] Furthermore, the automatic calibration unit includes: an acid washing subunit, a water washing subunit, a sample dilution subunit and a quantitative calibration subunit, and the subunits are connected in sequence through pipelines; the acid washing subunit and the water washing subunit are both equipped with independent peristaltic pumps and timing controllers for controlling the time and flow rate of the acid washing and water washing.

[0010] Furthermore, the pickling subunit includes: an acid liquid storage, an acid liquid distributor and a waste liquid collector; the acid liquid is a nitric acid solution with a mass fraction of 1%; the temperature of the pickling process is controlled at 25±2°C, and the pickling time is 10-15 minutes.

[0011] Furthermore, the water washing subunit comprises: an ultrapure water reservoir, a water washing distributor and a waste liquid collector; the water washing process uses ultrapure water with a resistivity of ≥18.2 MΩ·cm; and the water washing time is 5-8 minutes.

[0012] Furthermore, the sample dilution subunit includes: an automatic sampler, a diluent reservoir and a mixer; the automatic sampler is equipped with a microinjection pump for accurately controlling the volume ratio of the sample and the diluent; the diluent is a nitric acid solution with a mass fraction of 1%.

[0013] Furthermore, the mixer is made of polytetrafluoroethylene and has a built-in magnetic stirring device to ensure that the sample and the diluent are fully mixed; the mixing process takes 3-5 minutes and the rotation speed is 300-500rpm.

[0014] Furthermore, the quantitative calibration unit includes: a standard solution preparation device, an automatic quantitative device and a data acquisition system; the standard solution preparation device is used to prepare standard solutions of metal elements of different concentrations; the automatic quantitative device adopts a microinjection system to accurately control the injection volume.

[0015] Furthermore, the concentration calculation formula of the water-soluble metal elements in the system is: ,in, is the mass concentration of the target metal element in the atmosphere, in ng / m3 ; is the mass concentration of the target metal element in the sample solution obtained by the standard curve, in ng / mL; is the sample dilution multiple; is the volume of sample solution, in mL; is the sampling flow rate, in L / min; is the sampling time, in min.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This system can realize continuous automatic sampling and standardized pre-treatment of trace water-soluble metal elements in the atmosphere, significantly improving sampling efficiency and data reliability; it has a high degree of automation, greatly reducing manual operations and human errors; it is suitable for environmental monitoring and scientific research fields, and provides reliable technical support for the monitoring of trace water-soluble metal elements in the atmosphere. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flow chart of the water resources optimization scheduling method based on spatial coupling of water and land resources of the present invention; Figure 2 It is a schematic diagram of the structure of the gas dissolver of the present invention; Figure 3 It is a schematic diagram of the structure of the mixing growth chamber of the present invention.

[0018] Markings in the accompanying drawings: 1-main body, 2-air flow inlet, 3-air flow outlet, 4-gas selective permeable membrane, 5-absorption liquid inlet, 6-absorption liquid outlet, 7-main cavity, 8-main cavity inlet end, 9-steam generator, 10-electric refrigeration device, 11-breathable cavity, 12-mechanical pump interface. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described implementation mode is a part of the present invention, not all implementation modes. Based on the implementation modes of the present invention, all other implementation modes obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The system of the present invention can realize continuous automatic sampling and standardized pre-treatment of trace water-soluble metal elements in the atmosphere, significantly improving sampling efficiency and data reliability; the system adopts a modular design, and each functional unit is connected and controlled through a standard interface, with strong scalability and maintenance convenience. The entire system is uniformly deployed by a central controller to achieve full-process automated operation.

[0021] like Figure 1 As shown, it is a schematic diagram of the composition of the automatic sampling and pretreatment system of atmospheric trace water-soluble metal elements of the present invention, the system includes an automatic sampling module and a pretreatment module, the automatic sampling module is arranged in sequence from front to back: a gas introduction device, a gas dissolver and a mixing growth chamber, the mixing growth chamber is connected to the pretreatment module, and the pretreatment module includes: a sample enrichment unit and an automatic calibration unit.

[0022] The gas introduction device is used to introduce the atmospheric sample to be collected containing particulate matter into the gas dissolver; the gas introduction device adopts a combination design of a special PM2.5 cutter and an isokinetic sampling head. The cutting particle size of the cutter is 2.5μm, and the sampling flow rate can be adjusted within the range of 5-30L / min. The sampling head adopts an aerodynamic design to ensure that the airflow field is not significantly disturbed during the sampling process; a rain cover is set on the outside of the device, and is equipped with an automatic heating and defrosting function to ensure stable operation under different weather conditions. The system needs to be fully inspected and pretreated before each sampling: the cutter of the gas introduction device needs to be rinsed and dried with ultrapure water to ensure that there is no residue, the permeable membrane of the gas dissolver needs to be tested for integrity to ensure that there is no damage, all pipelines need to be repeatedly rinsed with ultrapure water, and a blank test is performed, and all sealing interfaces are checked to ensure the air tightness of the system.

[0023] The gas dissolver is used to separate the particles and gases in the atmospheric sample to be collected, and input the separated particles into the mixing growth chamber; the gas dissolver adopts a columnar design, with a main body length of 50cm and an inner diameter of 3cm, and is made of corrosion-resistant polytetrafluoroethylene material; the gas selective permeable membrane adopts a hydrophobic PTFE membrane with a pore size of 0.22μm and an effective area of ​​200cm². The absorption liquid (different absorption liquids are selected for different metal elements in different gases) is circulated at a constant speed through a precision peristaltic pump with a flow rate of 2mL / min. Under this structure, the separation and enrichment efficiency of heavy metal components in gaseous pollutants can reach more than 95%, while the loss rate of particles is controlled below 5%.

[0024] like Figure 2 The figure is a schematic diagram of the structure of a gas dissolver, which includes: a main body 1, a gas selective permeable membrane 4 arranged in the main body 1, and the gas selective permeable membrane 4 divides the internal space of the main body 1 into an outer absorption liquid channel and an intermediate gas and particle flow path; the main body 1 has an air flow inlet 2 and an air flow outlet 3, and the air flow passes through the intermediate gas and particle flow path from top to bottom; the main body 1 also has an absorption liquid inlet 5 and an absorption liquid outlet 6, which are respectively arranged at the top and bottom of the main body 1, for the circulation of the absorption liquid; the gas selective permeable membrane 4 can allow the gaseous components to pass through and be absorbed by the outer absorption liquid, while the particulate matter continues to move along the intermediate flow path, and the heavy metals in the gaseous components include at least: mercury, lead, cadmium, arsenic, chromium, and thallium.

[0025] The absorption liquid is selected according to the needs of different metal elements, for example: acidic potassium permanganate solution absorbs mercury in the gas, dilute nitric acid solution absorbs lead, cadmium, thallium, and chromium in the gas, and hydrochloric acid-ascorbic acid solution absorbs elemental arsenic in the gas; the absorption solution is not limited to this.

[0026] The mixed growth chamber comprises a steam generator and an electric refrigeration device, which are used to make the particles grow and condense in supersaturated water vapor to obtain a primary sample containing water-soluble metal elements, and the primary sample is transported to a sample enrichment unit through a pipeline.

[0027] The main cavity of the hybrid growth chamber is made of polycarbonate material with excellent thermal conductivity, and the inner wall is specially treated to be hydrophilic. The steam generator uses high-purity deionized water (resistivity ≥18.2MΩ·cm), and the heating power is accurately adjusted through the PID control system to maintain a relative humidity of more than 95% in the room. The electric refrigeration device uses a semiconductor refrigeration sheet with a temperature control accuracy of ±0.5℃. The slope of the conical outlet section is 15° to ensure that the droplets can flow out smoothly. The breathable cavity is made of porous titanium material with a porosity of 40%, which can produce a stable negative pressure environment in conjunction with a mechanical pump.

[0028] like Figure 3 As shown, it is a schematic diagram of the structure of the mixed growth chamber, which includes a main cavity 7, the inlet end 8 of the main cavity is connected to the outlet of the gas dissolver, and the other end transports the primary sample to the debubbler of the sample enrichment unit through a pipeline; the steam generator 9 is arranged below the main cavity, and comprises a pure water heating device for generating water vapor; the interior of the main cavity is made of plastic material, which is used to achieve full mixing of particles and water vapor, so that the particles grow in supersaturated water vapor; the electric refrigeration device 10 is arranged at the outlet end of the main cavity, which is used to condense the mixed airflow; the outlet end of the main cavity is a conical structure, and the periphery of the conical structure is arranged as a breathable cavity 11, and the upper part of the breathable cavity 11 is connected with a mechanical pump interface 12, which is used to connect a mechanical pump to cooperate with the electric refrigeration device 10 to achieve condensation of the mixed airflow.

[0029] The sample enrichment unit comprises a debubbler and a plastic syringe with a two-way valve; the debubbler is used to remove bubbles in the primary sample to eliminate the bubbles in the primary sample, obtain the sample to be enriched and transmit it to the plastic syringe through the two-way valve; the plastic syringe is used to enrich the sample to be enriched to obtain an enriched sample; the automatic calibration system sequentially performs acid washing, water washing, sample dilution and quantitative calibration on the enriched sample to complete the sample pretreatment process.

[0030] The automatic calibration unit comprises: an acid washing subunit, a water washing subunit, a sample dilution subunit and a quantitative calibration subunit, and each subunit is connected in sequence through pipelines; the acid washing subunit and the water washing subunit are both equipped with independent peristaltic pumps and timing controllers for controlling the time and flow rate of the acid washing and water washing.

[0031] The acid reservoir is made of acid-resistant polyethylene material with a capacity of 1L. The acid dispenser is equipped with a high-precision peristaltic pump, and the flow rate can be adjusted within the range of 0.1-10mL / min. The temperature control adopts water bath heating, equipped with a temperature sensor and PID control system to ensure that the pickling temperature is stable at 25±2℃. The waste liquid collector has an anti-overflow design and a liquid level alarm function.

[0032] The pickling subunit includes: an acid liquid storage, an acid liquid distributor and a waste liquid collector; the acid liquid is a nitric acid solution with a mass fraction of 1%; the temperature of the pickling process is controlled at 25±2°C, and the pickling time is 10-15 minutes.

[0033] The water washing subunit includes: an ultrapure water reservoir, a water washing distributor and a waste liquid collector; the water washing process uses ultrapure water with a resistivity of ≥18.2MΩ·cm; the water washing time is 5-8 minutes; the ultrapure water reservoir is made of special quartz glass and has an automatic degassing function. The water washing distributor adopts a multi-channel design and can process multiple samples at the same time. The entire water washing process is carried out in a clean environment to avoid sample contamination. The system is equipped with an online conductivity monitoring device to ensure the cleaning effect.

[0034] The sample dilution subunit includes: an automatic sampler, a diluent storage and a mixer; the automatic sampler is equipped with a microinjection pump for accurately controlling the volume ratio of the sample and the diluent; the diluent is a nitric acid solution with a mass fraction of 0.5%. The automatic sampler adopts an eight-channel design and is equipped with a ceramic plunger pump, and the injection accuracy is better than 0.5%. The diluent is prepared by the automatic weight method to ensure accurate concentration. The built-in magnetic stirrer of the mixer is made of Teflon material, and the stirring device has a soft start function to avoid sample splashing.

[0035] The mixer is made of polytetrafluoroethylene and has a built-in magnetic stirring device to ensure that the sample and the diluent are fully mixed; the mixing process takes 3-5 minutes and the rotation speed is 300-500rpm.

[0036] The quantitative calibration unit includes: a standard solution preparation device, an automatic quantitative device and a data acquisition system; the standard solution preparation device is used to prepare standard solutions of metal elements of different concentrations; the automatic quantitative device adopts a microinjection system to accurately control the injection volume. The standard solution preparation device adopts a fully automatic injection system equipped with a high-precision balance (accuracy 0.0001g). The automatic quantitative device uses a quartz capillary injection system, and the minimum injection volume can reach 0.1μL. The data acquisition system adopts a 32-bit high-speed A / D converter, and the sampling frequency can reach 100Hz.

[0037] The system also includes: a control module and a data processing module; the control module is used to control the automatic operation of each unit of the system; the data processing module is used to record and process sampling data and generate analysis reports; the system is also equipped with a touch screen display interface for real-time display of system operation status and data.

[0038] The concentration calculation formula of the water-soluble metal elements in the system is: ,in, is the mass concentration of the target metal element in the atmosphere, in ng / m 3 ; is the mass concentration of the target metal element in the sample solution obtained by the standard curve, in ng / mL; is the sample dilution multiple; is the volume of sample solution, in mL; is the sampling flow rate, in L / min; is the sampling time, in min.

[0039] The system of this embodiment has been field tested at multiple atmospheric monitoring sites. The results show that the system operates stably and has good data quality, which can meet the needs of environmental monitoring and scientific research. At the same time, the system has a high degree of automation, which greatly reduces manual operations, reduces human errors, and improves monitoring efficiency. The system of this embodiment shows excellent performance in practical applications. The specific performance parameters are as follows: 1. Sampling efficiency: At a sampling flow rate of 15L / min, the system's sampling efficiency for 0.1-2.5μm particles reaches over 90%.

[0040] 2. Analysis accuracy: For common water-soluble metal elements (such as Zn, Cu, Pb, Cd, etc.), the relative standard deviation (RSD) is controlled within 5%.

[0041] 3. Detection limit: Under the condition of 2-hour sampling time, the detection limit of the system for most metal elements can reach 0.1ng / m³.

[0042] 4. Automation level: The system can work continuously for more than 72 hours, during which time only reagents need to be replenished and waste liquid cleaned.

[0043] 5. Sample recovery rate: The recovery rate of the target elements is in the range of 85-115% as verified by the spike recovery experiment.

[0044] 6. Cross contamination: Cross contamination between adjacent samples is less than 0.1%.

[0045] 7. Stability: It can operate stably in an environment with a temperature of 5-35°C and a relative humidity of 20-90%.

[0046] The use of this system significantly improves the monitoring efficiency and data quality of trace water-soluble metal elements in the atmosphere, providing reliable technical support for related research. The modular design of the system also facilitates future functional expansion.

[0047] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. Automatic sampling and pre-treatment system for trace water-soluble metal elements in the atmosphere, characterized by: The system comprises an automatic sampling module and a pre-processing module, wherein the automatic sampling module is provided with: a gas introduction device, a gas dissolver and a mixed growth chamber in order from front to back, wherein the mixed growth chamber is connected to the pre-processing module, and the pre-processing module comprises: a sample enrichment unit and an automatic calibration unit; The gas introduction device is used to introduce the atmospheric sample to be collected containing particulate matter into the gas dissolver; the gas dissolver is used to separate the particulate matter and gas in the atmospheric sample to be collected, and input the separated particulate matter into the mixed growth chamber; the mixed growth chamber includes a steam generator and an electric refrigeration device, which are used to make the particulate matter grow and condense in supersaturated water vapor to obtain a primary sample containing water-soluble metal elements, and the primary sample is transported to the sample enrichment unit through a pipeline; The sample enrichment unit comprises a debubbler and a plastic syringe with a two-way valve; the debubbler is used to remove bubbles in the primary sample to eliminate the bubbles in the primary sample, obtain the sample to be enriched and transmit it to the plastic syringe through the two-way valve; the plastic syringe is used to enrich the sample to be enriched to obtain an enriched sample; the automatic calibration unit sequentially performs acid washing, water washing, sample dilution and quantitative calibration on the enriched sample to complete the sample pretreatment process.

2. The automatic sampling and pre-processing system for trace water-soluble metal elements in the atmosphere according to claim 1 is characterized in that: The gas atomizer comprises: a main body (1), a gas selective permeable membrane (4) arranged in the main body (1), the gas selective permeable membrane (4) dividing the internal space of the main body (1) into an outer absorption liquid channel and an intermediate gas and particle flow path; the main body (1) has an air flow inlet (2) and an air flow outlet (3), the air flow passes through the intermediate gas and particle flow path from top to bottom; the main body (1) also has an absorption liquid inlet (5) and an absorption liquid outlet (6), which are respectively arranged at the top and bottom of the main body (1) for circulating and replacing the absorption liquid; The gas selective permeable membrane (4) can allow gaseous heavy metal components to pass through and be absorbed by the outer absorption liquid, while the particles continue to move along the middle flow path. Different absorption liquids are selected for different metal elements in the gas.

3. The automatic sampling and pre-processing system for trace water-soluble metal elements in the atmosphere according to claim 2 is characterized in that: The mixing growth chamber comprises a main cavity (7), an inlet end (8) of the main cavity is connected to the outlet of the gas dissolver, and the other end of the main cavity is used to transport the primary sample to the debubbler of the sample enrichment unit through a pipeline; The steam generator (9) is arranged below the main cavity and comprises a pure water heating device for generating water vapor; the interior of the main cavity is constructed of a plastic material for achieving full mixing of particles and water vapor, so that the particles grow in the supersaturated water vapor; the electric refrigeration device (10) is arranged at the outlet of the main cavity for condensing the mixed airflow; the outlet of the main cavity is a conical structure, the outer periphery of the conical structure is arranged as a breathable cavity (11), and the upper part of the breathable cavity (11) is connected to a mechanical pump interface (12) for connecting a mechanical pump to cooperate with the electric refrigeration device (10) to achieve condensation of the mixed airflow.

4. The automatic sampling and pre-processing system for trace water-soluble metal elements in the atmosphere according to claim 3 is characterized in that: The automatic calibration unit comprises: an acid washing subunit, a water washing subunit, a sample dilution subunit and a quantitative calibration subunit, and each subunit is connected in sequence through pipelines; the acid washing subunit and the water washing subunit are both equipped with independent peristaltic pumps and timing controllers for controlling the time and flow rate of the acid washing and water washing.

5. The automatic sampling and pre-processing system for trace water-soluble metal elements in the atmosphere according to claim 4 is characterized in that: The pickling subunit includes: an acid liquid storage, an acid liquid distributor and a waste liquid collector; the acid liquid is a nitric acid solution with a mass fraction of 1%; the temperature of the pickling process is controlled at 25±2°C, and the pickling time is 10-15 minutes.

6. The automatic sampling and pre-processing system for trace water-soluble metal elements in the atmosphere according to claim 5 is characterized in that: The water washing subunit comprises: an ultrapure water storage, a water washing distributor and a waste liquid collector; the water washing process uses ultrapure water with a resistivity of ≥18.2 MΩ·cm; and the water washing time is 5-8 minutes.

7. The automatic sampling and pre-processing system for trace water-soluble metal elements in the atmosphere according to claim 6 is characterized in that: The sample dilution subunit comprises: an automatic sample injector, a diluent storage and a mixer; the automatic sample injector is equipped with a microinjection pump for accurately controlling the volume ratio of the sample and the diluent; the diluent is a nitric acid solution with a mass fraction of 0.5%.

8. The automatic sampling and pre-processing system for trace water-soluble metal elements in the atmosphere according to claim 7 is characterized in that: The mixer is made of polytetrafluoroethylene and has a built-in magnetic stirring device to ensure that the sample and the diluent are fully mixed; the mixing process takes 3-5 minutes and the rotation speed is 300-500rpm.

9. The automatic sampling and pre-processing system for trace water-soluble metal elements in the atmosphere according to claim 8, characterized in that: The quantitative calibration unit comprises: a standard solution preparation device, an automatic quantitative device and a data acquisition system; the standard solution preparation device is used to prepare metal element standard solutions of different concentrations; the automatic quantitative device adopts a microinjection system to accurately control the injection volume.

10. The automatic sampling and pre-processing system for trace water-soluble metal elements in the atmosphere according to claim 9, characterized in that: The concentration calculation formula of the water-soluble metal elements in the system is: ,in, is the mass concentration of the target metal element in the atmosphere, in ng / m 3 ; is the mass concentration of the target metal element in the sample solution obtained by the standard curve, in ng / mL; is the sample dilution multiple; is the volume of sample solution, in mL; is the sampling flow rate, in L / min; is the sampling time, in min.

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