Device and method for automatically collecting multiple components of atmospheric particulates

Abstract

The invention discloses an automatic collection device and method for multiple components of atmospheric particulates. The device comprises a particulate matter leading-in module, a rapid trapping module, a lifting rotary table and an automatic pretreatment module, the particulate matter leading-in module is used for screening and collecting atmospheric particulates with specific particle sizes, and the rapid trapping module enriches the particulates on the surface of a paper tape and automatically cuts a sample; the lifting rotary table and the automatic pretreatment module are used for automatic pretreatment and analysis of samples; the device realizes automatic collection, pretreatment and analysis of atmospheric particulates, can be used for real-time monitoring of various components such as water-soluble metals, water-soluble ions, polycyclic aromatic hydrocarbons and n-alkanes, and has the advantages of high automation degree, high analysis speed, wide application range and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of atmospheric monitoring, and particularly relates to an atmospheric particulate matter multi-component automatic collection device and method. BACKGROUND

[0002] Atmospheric particulate matter contains a variety of harmful substances, including water-soluble metal elements, water-soluble ions, polycyclic aromatic hydrocarbons and organic matter such as n-alkanes, which have important influences on human health and environmental quality.

[0003] At present, the analysis of atmospheric particulate matter components mainly adopts a traditional method of manual sampling, manual pretreatment and laboratory analysis, which has the following problems: the manual sampling and pretreatment process is tedious, time-consuming and labor-consuming; manual operation is easy to introduce pollution and increase measurement error; and sample analysis results cannot be obtained in real time, which is not conducive to timely discovery and treatment of sudden pollution events.

[0004] Therefore, it is of great significance to develop a device capable of automatically collecting and pretreating atmospheric particulate matter samples. SUMMARY

[0005] The purpose of the present application is to provide an atmospheric particulate matter multi-component automatic collection device and method to automatically collect atmospheric particulate matter, automatically pretreat samples and rapidly detect a variety of components; in order to achieve the above-mentioned purpose, the specific technical solutions are as follows:

[0006] In the first aspect, the present application provides an atmospheric particulate matter multi-component automatic collection device, which comprises a particulate matter introduction module, a rapid trapping module, a lifting rotary table and an automatic pretreatment module.

[0007] The particulate matter introduction module is arranged above the rapid trapping module, and the particulate matter introduction module comprises a cutting head, a gas diffusion pipe, a gas suction pump, a T-shaped shunt pipe and a flowmeter; the cutting head is arranged above the gas diffusion pipe, the gas inlet end of the gas diffusion pipe is connected with the cutting head, the gas outlet end of the gas diffusion pipe is connected with the T-shaped shunt pipe, the shunt outlet of the T-shaped shunt pipe is connected with a flowmeter, and the particulate matter outlet of the T-shaped shunt pipe is pressed against the front surface of the paper tape of the rapid trapping module, and the gas suction pump is connected at the same position on the back surface of the paper tape; atmospheric particulate matter enters the cutting head under the driving of the gas suction pump, the cutting head is used for screening the size of the particulate matter, only particulate matter of a specific size is allowed to enter the gas diffusion pipe, the gas diffusion pipe is used for removing acidic and alkaline gases in the atmosphere that affect the analysis of the particulate matter, and the T-shaped shunt pipe is used for shunting the excess gas flow so that the particulate matter enters the rapid trapping module under a fixed flow.

[0008] The rapid trapping module comprises a paper tape, a paper tape driving motor, an air suction pressure head and a falling film device, the paper tape moves in a fixed direction under the action of the paper tape driving motor, and the air suction pressure head is tightly pressed with the particulate matter outlet of the T-shaped shunt pipe; the falling film device is fixed in front of the particulate matter outlet of the T-shaped shunt pipe along the moving direction of the paper tape, used for cutting and introducing the paper tape disc with collected samples into a reagent bottle with pre-prepared solvent to obtain a primary sample.

[0009] The lifting rotary table is provided with four reagent bottle fixing seats for fixing reagent bottles, the fixing seats can be connected with an ultrasonic pool, an automatic pretreatment module, a cleaning and sample changing position and a sample inlet of an analysis instrument under the lifting and / or rotation of the lifting rotary table; the ultrasonic pool is used for fully dissolving water-soluble metals in the primary sample in a dilute acid solution under ultrasonic action; the automatic pretreatment module at least comprises an automatic calibration device, the automatic calibration device is used for controlling the dilution amount of a standard solution, automatically gradient diluting the standard solution, automatically forming a standard curve, quantifying and calibrating elements; the automatic calibration device is also used for diluting the concentration of the collected primary sample, reducing the matrix effect and obtaining a pretreatment sample; the cleaning and sample changing position is used for replacing the reagent bottle after analysis with a reagent bottle with pre-prepared solvent and automatically cleaning the reagent bottle after analysis; the sample inlet of the analysis instrument receives the pretreatment sample, and the pretreatment sample is transmitted to the analysis instrument through the sample inlet for subsequent atmospheric particulate matter concentration analysis.

[0010] Further, the particulate matter cutting head is replaceable and comprises a TSP cutting head, a PM10 cutting head, a PM2.5 cutting head and a PM1 cutting head; the cutting head is used for screening the size of particulate matter and only allows particulate matter of a specific size to enter the gas diffusion pipe, the specific size refers to the diameter of particulate matter with an aerodynamic equivalent diameter less than or equal to the corresponding cutting head screening.

[0011] Further, the paper tape driving motor is electrically connected with a control system, every 30 minutes of sampling, the air suction pressure head is separated from the paper tape, the paper tape driving motor drives the paper tape to move forward by 3cm to the next position, the air suction pressure head re-fixes the paper tape, and the rapid trapping module continues to collect the next 30 minutes.

[0012] Further, the inner diameter of the falling film device is consistent with the diameter of the sample point on the paper tape.

[0013] Further, the pre-prepared solvent is one of 2ml of 1% nitric acid solution, ultrapure water, n-hexane and dichloromethane.

[0014] Further, the automatic calibration module comprises a standard solution storage unit, an automatic dilution unit and a solution conductivity monitoring unit; the standard solution storage unit stores standard solutions, and the automatic dilution unit automatically controls the dilution ratio according to the solution conductivity monitored by the solution conductivity monitoring unit.

[0015] In a second aspect, the present application provides an automatic multi-component atmospheric particulate matter collection method, which uses the automatic multi-component atmospheric particulate matter collection device of the first aspect, and comprises the following steps:

[0016] In step S1, according to the particle size of the particulate matter to be measured, a corresponding cutting head is installed on the particulate matter introduction device, 2 ml of 1% nitric acid solution is added in advance in the reagent bottle for the extraction of water-soluble metals, or ultrapure water is added for the extraction of water-soluble ions, or n-hexane is added for the extraction of n-alkanes, or dichloromethane is added for the extraction of polycyclic aromatic hydrocarbons; the reagent bottle is placed on the reagent bottle fixing seat, and a sampling special paper tape is installed on the paper tape driving device.

[0017] In step S2, the air suction pump is started, the atmospheric sample is introduced into the gas diffusion pipe after the particulate matter larger than the target particle size is removed by the cutting head, the interfering gas is removed by the gas diffusion pipe, and the particulate matter is enriched on the surface of the paper tape under the action of the air suction pressure head after being adjusted by the T-shaped shunt pipe and passing through the paper tape at a fixed flow rate. Each sampling point is continuously sampled for 30 minutes.

[0018] In step S3, when one sampling point completes 30 minutes of sampling, the paper tape driving motor drives the paper tape to move 3 cm into the next sampling position, and the lifting and rotating table performs the following actions:

[0019] The lifting table rises to move the paper tape to the film falling position, the film falling device falls to cut off the paper disc with the collected sample and introduce it into the reagent bottle with the prepared solvent to obtain a primary sample, and the lifting table descends and rotates to the ultrasonic pool position, and the reagent bottle is placed in the ultrasonic pool for ultrasonic oscillation for at least 20 minutes.

[0020] The concentration of the particulate matter in the primary sample is calculated according to the following formula: Wherein, C is the concentration of the component to be measured in the particulate matter, unit μg / m 3 ; m is the measured mass of the component to be measured, unit μg; Q is the sampling flow rate, unit m 3 / min; t is the sampling time, unit min; f d is the dilution factor.

[0021] Step S4, the lifting platform is rotated to an automatic calibration module, the automatic calibration module dilutes the collected primary sample concentration to obtain a pretreatment sample; when the automatic calibration module dilutes the primary sample, a standard solution storage unit and an automatic dilution unit are used to prepare standard solutions with different concentration gradients, a standard curve is established, and the standard curve is used for quantitative analysis of the target component in the sample.

[0022] The solution conductivity monitoring unit monitors the conductivity of the sample solution in real time, and when the conductivity exceeds the preset threshold, the dilution ratio of the pretreatment sample is automatically adjusted by monitoring the conductivity of the primary sample solution, and the dilution factor f d According to the sample solution conductivity, the following formula is automatically adjusted:

[0023] Wherein, sigma is the conductivity of the primary sample solution, unit: mS / cm; sigma1 is the preset conductivity threshold, sigma0 is 2.0 mS / cm; Indicates the minimum integer not less than .

[0024] Step S5, control the lifting rotary table, align the pretreatment sample with the sample inlet of the analysis instrument, and transmit the pretreatment sample to the analysis instrument through the sample inlet, select the corresponding analysis method according to the component to be measured, and obtain the concentration of the target component in the atmospheric particulate matter.

[0025] According to the component to be measured, the corresponding analysis method is selected, including: using ICP-MS to analyze water-soluble metal elements; using ion chromatography to analyze water-soluble salt; using GC-MS to analyze n-alkane and polycyclic aromatic hydrocarbon organic components.

[0026] Step S6, the lifting rotary table transfers the reagent bottle that has completed analysis to a cleaning and sample changing position, the cleaning and sample changing position first places a new reagent bottle pre-added with a corresponding solvent on the reagent bottle fixing seat, then automatically cleans the reagent bottle that has completed analysis, and the cleaned reagent bottle is used for next round of sample collection after being added with a corresponding solvent again.

[0027] Further, the sampling flow of the particulate matter introduction device is 16.7 L / min.

[0028] Further, the frequency of the ultrasonic oscillation is 40 kHz.

[0029] Further, the automatic dilution unit adopts a cooperative working mode of a micro-injection pump and a peristaltic pump, the micro-injection pump is used to control the addition amount of the standard solution, the peristaltic pump is used to control the addition amount of the dilution solvent, and accurate dilution of the sample and the standard solution is realized.

[0030] Compared with the prior art, the present application has the following beneficial effects:

[0031] The device of the present invention can reduce manual pre-processing operations, reduce uncontrollable human operation errors, and improve the accuracy and repeatability of analysis results; it changes the situation in which the monitoring method of atmospheric particulate matter still remains in the traditional off-line analysis method of sending the sampler to the laboratory for analysis after sampling, and realizes real-time monitoring, which is conducive to the timely discovery and handling of sudden pollution incidents; the device can be applied to the automatic collection and pre-processing of different particulate matter by replacing different solvents, has wide applicability, and can simultaneously monitor multiple components such as water-soluble metals, water-soluble ions, polycyclic aromatic hydrocarbons and normal alkanes. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the partial components of an automatic multi-component collection device for atmospheric particulate matter according to the present invention;

[0033] Figure 2 It is a schematic diagram of the lifting and rotating platform of the present invention.

[0034] Markings in the accompanying drawings: 1-cutting head, 2-gas diffusion tube, 3-T-shaped diverter, 4-flow meter, 5-vacuum pump, 6-paper tape, 7-paper tape drive motor, 8-vacuum pressure head, 9-film dropper, 10-lifting and rotating table, 11-reagent bottle holder, 12-ultrasonic pool, 13-automatic pretreatment module, 14-cleaning and sample exchange position, 15-analytical instrument sampling port. DETAILED DESCRIPTION

[0035] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only part of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] Example 1

[0037] like Figure 1 Figure 1 shows a schematic diagram of the components of a multi-component automatic atmospheric particulate matter collection device according to the present invention. The entire device, measuring 80 cm × 60 cm × 120 cm (length × width × height), primarily consists of a particle inlet module, a rapid collection module, a lifting and rotating platform, and an automatic pre-treatment module. All modules are made of 304 stainless steel to ensure corrosion resistance and longevity.

[0038] The automatic collection device includes: a particle introduction module, a rapid capture module, a lifting and rotating table and an automatic pre-processing module.

[0039] The particle introduction module is arranged above the rapid trapping module, and the particle introduction module comprises a cutting head 1, a gas diffusion pipe 2, an air suction pump 5, a T-shaped shunt pipe 3 and a flow meter 4; the cutting head 1 is arranged above the gas diffusion pipe 2, the air inlet end of the gas diffusion pipe 2 is connected with the cutting head 1, the air outlet end of the gas diffusion pipe 2 is connected with the T-shaped shunt pipe 3, the shunt outlet of the T-shaped shunt pipe 3 is connected with the flow meter 4, the particle outlet of the T-shaped shunt pipe 3 is pressed against the front of the paper tape 6 of the rapid trapping module, and the air suction pump 5 is connected to the same position on the back of the paper tape 6; the atmospheric particles enter the cutting head 1 under the driving of the air suction pump 5, the cutting head 1 is used for screening the size of the particles, and only the particles with a specific size are allowed to enter the gas diffusion pipe 2, the gas diffusion pipe 2 is used for removing the acidic and alkaline gases in the atmosphere which affect the analysis of the particles, and the T-shaped shunt pipe 3 is used for shunting the excess gas flow, so that the particles enter the rapid trapping module under a fixed flow.

[0040] The particle introduction module is arranged above the rapid trapping module at about 30 cm, so as to ensure the stability of the gas flow. The gas diffusion pipe 2 is a porous glass pipe coated with Na2CO3 on the inner wall, with a length of 20 cm and an inner diameter of 1 cm, and is used for removing acidic gases such as SO2 and NO2; or a porous glass pipe coated with H3PO4 on the inner wall is used for removing alkaline gases such as NH3. The T-shaped shunt pipe 3 is made of polytetrafluoroethylene, with an inner diameter of 8 mm of the main pipe and an inner diameter of 6 mm of the branch pipe. The maximum air suction flow of the air suction pump 5 can reach 20 L / min, and the air suction pump 5 is driven by a brushless DC motor, has the characteristics of low noise and long service life. The measurement range of the flow meter 4 is 0-20 L / min, and the accuracy is ±1%.

[0041] The rapid trapping module comprises a paper tape 6, a paper tape driving motor 7, an air suction pressure head 8 and a film falling device 9. The paper tape moves in a fixed direction under the action of the paper tape driving motor 7, and the air suction pressure head 8 tightly presses the paper tape and the particle outlet of the T-shaped shunt pipe 3. The film falling device 9 is fixed in front of the particle outlet of the T-shaped shunt pipe 3 along the moving direction of the paper tape, and is used for cutting and introducing the paper tape disc with collected samples into a reagent bottle with a prepared solvent, so as to obtain a primary sample. The paper tape 6 is made of quartz fiber filter paper, with a width of 2.5 cm and a length of 50-100 m which can be selected according to needs. The paper tape driving motor 7 is a stepping motor, with a step angle of 1.8° and a torque of 0.3 N·m, and is provided with a speed reducer to realize accurate positioning. The air suction pressure head 8 is provided with a fluororubber sealing ring to ensure air tightness. The film falling device 9 is made of stainless steel, with an inner diameter consistent with the diameter of the sample point (about 15 mm), and the cutting edge is specially treated to ensure neat cutting.

[0042] The lifting rotary table 10 is provided with four reagent bottle fixing seats for fixing the reagent bottles. Figure 2As shown, the fixed seat 11 can be connected with the ultrasonic pool 12, the automatic pretreatment module 13, the cleaning sample changing position 14 and the sample inlet 15 of the analysis instrument respectively under the lifting and / or rotation of the lifting rotary table; the ultrasonic pool 12 is used for fully dissolving the water-soluble metal in the primary sample in the dilute acid solution under the action of ultrasonic waves; the automatic pretreatment module 13 at least comprises an automatic calibration device, which is used for controlling the dilution amount of the standard solution, automatically gradient diluting the standard solution, automatically forming a standard curve, quantifying and calibrating the element; the automatic calibration device is also used for diluting the concentration of the collected primary sample, reducing the matrix effect and obtaining a pretreatment sample; the cleaning sample changing position 14 is used for replacing the reagent bottle which has been analyzed with a reagent bottle with a pre-prepared solvent and automatically cleaning the reagent bottle which has been analyzed; the sample inlet 15 of the analysis instrument receives the pretreatment sample, transmits the pretreatment sample to the analysis instrument through the sample inlet and performs subsequent analysis of the concentration of atmospheric particulate matter.

[0043] The lifting stroke of the lifting rotary table 10 is 0-150mm, and the positioning accuracy is ±0.1mm; the rotation angle range is 0-360°, and the angle accuracy is ±0.1°. The four reagent bottle fixed seats 11 adopt elastic buckle design and are suitable for 10-20mL sample bottles. The volume of the ultrasonic pool 12 is 2L, and a constant temperature control system (temperature range 20-60℃, accuracy ±0.5℃) is provided. The automatic calibration device in the automatic pretreatment module 13 adopts a high-precision injection pump (flow range 0.1μL / min-10mL / min).

[0044] The particulate matter cutting head is replaceable and comprises a TSP cutting head, a PM10 cutting head, a PM2.5 cutting head and a PM1 cutting head; the cutting head is used for screening the size of particulate matter and only allows particulate matter of a specific size to enter the gas diffusion pipe, wherein the specific size refers to the diameter of particulate matter with an aerodynamic equivalent diameter less than or equal to the corresponding cutting head; the cutting particle size of the TSP cutting head is 100μm, the cutting particle size of the PM10 cutting head is 10μm, the cutting particle size of the PM2.5 cutting head is 2.5μm and the cutting particle size of the PM1 cutting head is 1μm. Each cutting head adopts impact separation principle and realizes separation of different particle sizes by adjusting the nozzle diameter and the spacing between the impact plates; the separation efficiency of the cutting efficiency curve at the target particle size is 50%±5%.

[0045] The paper tape driving motor is electrically connected with the control system, the air suction pressure head is separated from the paper tape every 30 minutes of sampling, the paper tape driving motor drives the paper tape to move forward by 3cm to the next position, the air suction pressure head re-fixes the paper tape, and the rapid trapping module continues to collect the next 30 minutes.

[0046] The control system adopts a PLC controller, has power-off memory and fault alarm functions. The position of the paper tape is detected in real time by a photoelectric sensor, and the positioning accuracy is better than ±1 mm. After each sampling period ends, the controller sends a signal to lift the suction pressure head by 3 mm, and then starts the paper tape driving motor to ensure that the paper tape does not produce friction damage during movement.

[0047] The inner diameter of the falling film device is consistent with the diameter of the sample point on the paper tape.

[0048] The solvent is prepared in advance as 2ml of 1% nitric acid solution, ultrapure water, n-hexane, dichloromethane; when analyzing water-soluble metals, 1% nitric acid solution (superior grade) is selected, which can effectively dissolve and stabilize metal ions; when analyzing water-soluble ions, ultrapure water with a resistivity of ≥18.2MΩ·cm is used; when analyzing n-alkanes, chromatographically pure n-hexane (purity ≥99.9%) is used; when analyzing polycyclic aromatic hydrocarbons, chromatographically pure dichloromethane (purity ≥99.9%) is used.

[0049] The automatic calibration module comprises a standard solution storage unit, an automatic dilution unit and a solution conductivity monitoring unit; the standard solution storage unit stores standard solutions, the automatic dilution unit automatically controls the dilution ratio according to the solution conductivity monitored by the solution conductivity monitoring unit; the standard solution storage unit comprises 10 standard solution storage bottles of 5mL, which are made of brown glass and are equipped with a heat insulation layer; the automatic dilution unit adopts a high-precision syringe pump (minimum resolution 0.1μL) and an eight-channel peristaltic pump; the measurement range of the solution conductivity monitoring unit is 0-100mS / cm, and the accuracy is ±1%. The whole system is automatically controlled by a computer program, and the dilution ratio can be adjusted in real time according to the measurement results.

[0050] Example 2

[0051] The embodiment discloses an automatic multi-component collection method of atmospheric particulate matter, which adopts the automatic multi-component collection device of atmospheric particulate matter in example 1, and comprises the following steps:

[0052] Step S1, according to the particle size of the particulate matter to be measured, the corresponding cutting head is installed on the particulate matter introduction device, 2ml of 1% nitric acid solution is added in the reagent bottle for the extraction of water-soluble metals, or ultrapure water is added for the extraction of water-soluble ions, or n-hexane is added for the extraction of n-alkanes, or dichloromethane is added for the extraction of polycyclic aromatic hydrocarbons; the reagent bottle is placed on the reagent bottle fixing seat, and the sampling special paper tape is installed on the paper tape driving device.

[0053] Operators should select the appropriate cutting head based on ambient air quality standards and monitoring requirements. When replacing a cutting head, check the integrity of the sealing ring to ensure it is securely installed. Reagent bottles must be pre-treated by acid cleaning, rinsing with ultrapure water, and drying before use. When installing paper tape, pay attention to its orientation and ensure that the surface is flat and wrinkle-free. It is recommended to perform a blank test after each installation of a new paper tape to confirm that the system is free of contamination.

[0054] In step S2, the vacuum pump is started to allow the atmospheric sample to pass through the cutting head to remove particles larger than the target particle size and then enter the gas diffusion tube. The interfering gas is removed through the gas diffusion tube, and the atmospheric sample is diverted and adjusted by the T-shaped diverter tube and passes through the paper tape at a fixed flow rate. Under the action of the vacuum pressure head, the particles are enriched on the surface of the paper tape. Sampling is continued for 30 minutes at each sampling point.

[0055] Preheat the system for 15 minutes before starting. Set the initial flow rate of the vacuum pump to 17 L / min and adjust it to 16.7 L / min using a T-shaped manifold. Record the flow meter reading every hour during system operation. If the deviation exceeds ±5%, adjust it immediately. Monitor the tape pressure during sampling to ensure airtightness. The actual sampling volume at each sampling point is approximately 0.5 m 3 .

[0056] Step S3: After a sampling point completes 30 minutes of sampling, the paper tape drive motor moves the paper tape 3 cm to the next sampling position, and the lifting and rotating table performs the following actions:

[0057] The lifting platform rises to move the paper tape to the film dropper position, and the film dropper falls to intercept the paper tape disc with the collected sample and introduce it into the reagent bottle with pre-prepared solvent to obtain the primary sample. The lifting platform descends and rotates to the ultrasonic pool position, and the reagent bottle is placed in the ultrasonic pool for ultrasonic vibration for at least 20 minutes.

[0058] Before the paper strip is moved, the controller reduces the suction head pressure to prevent damage. The downward pressure of the film dropper is controlled at 2 mm / s to ensure a smooth cut. When the reagent bottle is fixed in the ultrasonic bath, the liquid level should be flush with the water level of the ultrasonic bath. The ultrasonic temperature is set to 40°C, the power is set to 200W, and stirring is performed every 5 minutes. The sampling point diameter is 15 mm. The particle load calculated based on the sampling flow rate is generally between 10 and 500 μg.

[0059] The concentration of particulate matter in the primary sample is calculated according to the following formula: Where C is the concentration of the component to be measured in the particulate matter, in μg / m 3 ; m is the mass of the component to be measured, in μg; Q is the sampling flow rate, in m 3 / min; t is the sampling time, in min; f d is the dilution factor;

[0060] Step S4, the lifting platform rotates to an automatic calibration module, which dilutes the collected primary sample concentration to obtain a pretreatment sample; when the automatic calibration module dilutes the primary sample, it prepares standard solutions with different concentration gradients through a standard solution storage unit and an automatic dilution unit, establishes a standard curve, and is used for quantitative analysis of target components in the sample;

[0061] The solution conductivity monitoring unit monitors the conductivity of the sample solution in real time, and when it is detected that the conductivity exceeds the preset threshold, the dilution ratio is automatically adjusted to obtain the pretreatment sample by monitoring the conductivity of the primary sample solution, and the dilution factor f d According to the sample solution conductivity, the following formula is automatically adjusted:

[0062] Wherein, σ is the conductivity of the primary sample solution, unit: mS / cm; σ0 is the preset conductivity threshold, σ0 is 2.0 mS / cm; Indicates the smallest integer not less than .

[0063] The standard solution is selected from national standard substances, and 7 concentration points are used to draw a standard curve, and the correlation coefficient R 2 It needs to be greater than 0.999. Taking the determination of water-soluble metals as an example, the standard series concentration range is 0.1-100 μg / L, and each concentration point is determined in parallel for 3 times. When diluting the sample, first take 20 μL of the sample to determine the conductivity, and automatically calculate the dilution multiple according to the determination result.

[0064] Step S5, control the lifting rotary table to align the pretreatment sample with the sample inlet of the analysis instrument, and transmit the pretreatment sample to the analysis instrument through the sample inlet, select the corresponding analysis method according to the component to be measured, and obtain the concentration of the target component in the atmospheric particulate matter.

[0065] According to the component to be measured, the corresponding analysis method is selected, including: using ICP-MS to analyze water-soluble metal elements; using ion chromatography to analyze water-soluble salts; using GC-MS to analyze n-alkanes and polycyclic aromatic hydrocarbon organic components; when ICP-MS is used for analysis, an internal standard correction method is used, and the internal standard elements are In, Re, etc. When analyzing anions by ion chromatography, the eluent is 3.5 mmol / L Na2CO3+1.0 mmol / L NaHCO3, and the flow rate is 1.2 mL / min; when analyzing cations, the eluent is 20 mmol / L methanesulfonic acid, and the flow rate is 1.0 mL / min. When GC-MS is used for analysis, a DB-5MS capillary column (30 m x 0.25 mm x 0.25 μm) is used, and the carrier gas is high-purity helium.

[0066] Step S6, the lifting rotary table transfers the reagent bottle after analysis to the cleaning and sample changing position, the cleaning and sample changing position firstly places the new reagent bottle pre-added with the corresponding solvent on the reagent bottle fixing seat, and then automatically cleans the reagent bottle after analysis, and the reagent bottle after cleaning is used for the next round of sample collection after being added with the corresponding solvent again.

[0067] The cleaning procedure includes: acid cleaning (5% nitric acid, 3 times) → ultrapure water flushing (5 times) → target solvent rinsing (2 times). The liquid amount of each cleaning step is 5 mL, and the oscillation time is 30 s. The reagent bottle after cleaning is subjected to drying treatment (60 DEG C, 2 h) to ensure no residual solvent. After the system is operated for 24 hours, all pipelines are subjected to a comprehensive cleaning.

[0068] The sampling flow of the particulate matter introduction device is 16.7 L / min; and the frequency of ultrasonic oscillation is 40 kHz.

[0069] The automatic dilution unit adopts a cooperative working mode of a micro-injection pump and a peristaltic pump, the micro-injection pump is used to control the addition amount of the standard solution, the peristaltic pump is used to control the addition amount of the dilution solvent, and the accurate dilution of the sample and the standard solution is realized.

[0070] In addition, the method of the embodiment has been practically verified, the automatic sampling device is arranged in an industrial park, and the environmental air quality is monitored. The monitoring point is arranged at the center position of the park, and the continuous monitoring is performed for 7 days. The sampling time is from 8:00 to 8:00 of the next day every day. In this application, the PM2.5 cutting head is selected for sampling, the sampling flow is set to 16.7 L / min, and four sampling time periods are set at 8:00, 14:00, 20:00 and 2:00 of the next day every day, and four sample points are collected in each time period. Four reagent bottles are set, 2 mL of 1% nitric acid solution is added into each reagent bottle for determining water-soluble metals (Cu, Pb, Zn, Cd and the like), 2 mL of ultrapure water is added into each reagent bottle for determining water-soluble ions (SO42-, NO3-, NH4+ and the like), 2 mL of n-hexane is added into each reagent bottle for determining normal alkanes (C20-C40), and 2 mL of dichloromethane is added into each reagent bottle for determining polycyclic aromatic hydrocarbons (phenanthrene, pyrene and the like).

[0071] The application results show that the device significantly improves the automation degree and efficiency of the monitoring work. Compared with the traditional manual method, the device reduces the labor cost by about 70%, and improves the sample processing efficiency by about 380%. The traditional manual method needs 3 technicians to work in shifts for 24 hours for sampling and pretreatment, and the number of samples processed per day is about 20; and the device only needs one technician for daily maintenance and supervision, and the number of samples processed per day reaches 96.

[0072] In terms of analysis accuracy, taking lead (Pb) element as an example for repetitive testing (n = 20), the RSD of the traditional manual method is 8.5%, while the RSD of the device is only 3.2%, and the measurement accuracy is increased by about 62%. In terms of sample analysis timeliness, the traditional manual method needs 2-3 days from sampling to obtaining the analysis results, while the device can obtain the analysis results within 30 minutes, and the timeliness is increased by about 95%.

[0073] During the 7-day continuous monitoring period, the analysis results of 8 water-soluble metals, 6 water-soluble ions, 12 n-alkanes and 8 polycyclic aromatic hydrocarbons target substances showed that the detection rate of water-soluble metals was 100%, and the relative error was less than 10%; the detection rate of water-soluble ions was 100%, and the relative error was less than 8%; the detection rate of n-alkanes was 95%, and the relative error was less than 12%; the detection rate of polycyclic aromatic hydrocarbons was 93%, and the relative error was less than 15%. These data fully prove that the device has reliable multi-component analysis capability.

[0074] The traditional manual method needs 4-6 hours to find and confirm the abnormal concentration of pollutants, while the device can find and confirm the abnormal concentration of pollutants within 30 minutes and timely issue a warning signal. In the actual monitoring process, the device successfully found and warned twice about the abnormality of pollutants: at 14:00 on July 2, the concentration of polycyclic aromatic hydrocarbons suddenly increased by 5 times compared with the previous value, which was caused by the burning of waste by an enterprise in the park; at 2:00 on July 5, the concentration of heavy metal lead was abnormal, which increased by 8 times compared with the previous value, which was caused by the illegal discharge of an enterprise at night in the park.

[0075] Through actual application verification, the present application has the following outstanding advantages: first, the present application significantly reduces labor cost and improves work efficiency, reduces labor operation links and labor intensity, improves sample processing throughput and increases monitoring frequency, realizes 24-hour continuous monitoring and does not need manual on-duty. Second, the present application improves analysis accuracy and guarantees data quality, reduces human error through automatic operation, improves repeatability through standardized process, and ensures accuracy through real-time calibration. Third, the present application realizes the functions of rapid response and timely warning, significantly shortens the analysis period, improves timeliness, can find abnormalities in real time and respond quickly, and effectively prevents environmental pollution accidents. Finally, the present application has wide application range and high application value, can monitor multiple pollutant components at the same time, is suitable for different environmental monitoring scenes, and provides reliable data support for environmental management.

[0076] The present embodiment fully proves the feasibility and superiority of the present application in practical application, and has important significance for improving the environmental air quality monitoring capability, and the device can be widely applied to environmental monitoring stations, industrial parks, urban air quality monitoring networks and other scenes, and provides reliable technical support for environmental management and pollution prevention.

[0077] The above detailed description of the specific embodiments of the present application has been given to understand the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An automatic multi-component collection device for atmospheric particulate matter, characterized in that: The automatic collection device includes: a particle introduction module, a rapid capture module, a lifting and rotating platform and an automatic pre-processing module; The particle introduction module is arranged above the rapid capture module, and the particle introduction module includes: a cutting head, a gas diffusion tube, an air pump, a T-shaped diverter tube and a flow meter; the cutting head is arranged above the gas diffusion tube, the air inlet end of the gas diffusion tube is connected to the cutting head, the air outlet end of the gas diffusion tube is connected to the T-shaped diverter tube, the diversion outlet of the T-shaped diverter tube is connected to the flow meter, the particle outlet of the T-shaped diverter tube is pressed against the front side of the paper tape of the rapid capture module, and the air pump is connected to the same position on the back side of the paper tape; atmospheric particles enter the cutting head driven by the air pump, the cutting head is used to screen the size of the particles, and only particles of a specific size are allowed to enter the gas diffusion tube, the gas diffusion tube is used to remove acidic and alkaline gases in the atmosphere that affect particle analysis, and the T-shaped diverter tube is used to divert excess gas flow, so that the particles enter the rapid capture module at a fixed flow rate; The rapid capture module includes a paper tape, a paper tape drive motor, an air pump, and a film dropper. The paper tape moves in a fixed direction under the action of the paper tape drive motor, and the air pump tightly presses the paper tape against the particle outlet of the T-shaped shunt tube. The film dropper is fixed in front of the particle outlet of the T-shaped shunt tube along the direction of paper tape movement, and is used to intercept the paper tape disc with the collected sample and introduce it into a reagent bottle with a pre-prepared solvent to obtain a primary sample. The lifting and rotating platform is provided with four reagent bottle fixing seats for fixing reagent bottles. The fixing seats can be connected to the ultrasonic pool, automatic pretreatment module, cleaning and sample exchange position and the sampling port of the analytical instrument respectively when the lifting and / or rotation of the lifting and rotating platform is performed; the ultrasonic pool is used to fully dissolve the water-soluble metals in the primary sample in the dilute acid solution under the action of ultrasound; the automatic pretreatment module includes at least an automatic calibration device, which is used to control the dilution amount of the standard solution, automatically perform gradient dilution on the standard solution, automatically form a standard curve, and quantify and calibrate the elements; the automatic calibration device is also used to dilute the concentration of the collected primary sample, reduce the matrix effect, and obtain a pretreated sample; the cleaning and sample exchange position is used to replace the analyzed reagent bottle with a reagent bottle with a pre-prepared solvent and automatically clean the analyzed reagent bottle; the sampling port of the analytical instrument receives the pretreated sample, and transmits the pretreated sample to the analytical instrument through the sampling port for subsequent atmospheric particulate matter concentration analysis.

2. The automatic multi-component collection device for atmospheric particulate matter according to claim 1, characterized in that: The particulate matter cutting head is replaceable and includes: a TSP cutting head, a PM10 cutting head, a PM2.5 cutting head, and a PM1 cutting head; the cutting head is used to screen the size of particulate matter, allowing only particles of a specific size to enter the gas diffusion tube. The specific size refers to the diameter of the particles with an aerodynamic equivalent diameter less than or equal to the diameter of the particles screened by the corresponding cutting head.

3. The automatic multi-component collection device for atmospheric particulate matter according to claim 1, characterized in that: The paper tape drive motor is electrically connected to the control system. Every 30 minutes of sampling, the vacuum pressure head is separated from the paper tape, and the paper tape drive motor drives the paper tape forward 3 cm to the next position. The vacuum pressure head re-fixes the paper tape, and the rapid capture module continues to collect for the next 30 minutes.

4. The automatic multi-component collection device for atmospheric particulate matter according to claim 1, characterized in that: The inner diameter of the film dropper is consistent with the diameter of the sample point on the paper tape.

5. The automatic multi-component collection device for atmospheric particulate matter according to claim 1, characterized in that: The pre-prepared solvent is 2 ml of one of 1% nitric acid solution, ultrapure water, n-hexane, and dichloromethane.

6. The automatic multi-component collection device for atmospheric particulate matter according to claim 1, characterized in that: The automatic calibration module includes: a standard solution storage unit, an automatic dilution unit and a solution conductivity monitoring unit; the standard solution storage unit stores a standard solution, and the automatic dilution unit automatically controls the dilution ratio through the solution conductivity monitored by the solution conductivity monitoring unit.

7. A method for automatically collecting multiple components of atmospheric particulate matter, using the automatic collection device for multiple components of atmospheric particulate matter according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: Step S1: Select a cutting head corresponding to the particle size of the particles to be measured and install it on the particle introduction device. Pre-add 2 ml of 1% nitric acid solution for extracting water-soluble metals, ultrapure water for extracting water-soluble ions, n-hexane for extracting n-alkanes, or dichloromethane for extracting polycyclic aromatic hydrocarbons to the reagent bottle. Place the reagent bottle on the reagent bottle holder and install a sampling paper tape on the paper tape drive device. Step S2: Start the vacuum pump to allow the atmospheric sample to pass through the cutting head to remove particles larger than the target particle size and then enter the gas diffusion tube. After the interfering gas is removed by the gas diffusion tube, the atmospheric sample is diverted and adjusted by the T-shaped diverter tube and passes through the paper tape at a fixed flow rate. Under the action of the vacuum pressure head, the particles are enriched on the surface of the paper tape. Sampling is continued for 30 minutes at each sampling point. Step S3: After a sampling point completes 30 minutes of sampling, the paper tape drive motor moves the paper tape 3 cm to the next sampling position, and the lifting and rotating table performs the following actions: The lifting platform rises to move the paper tape to the film dropper position, and the film dropper falls to intercept the paper tape disc with the collected sample and introduce it into the reagent bottle with the solvent prepared in advance to obtain the primary sample. The lifting platform descends and rotates to the ultrasonic pool position, and the reagent bottle is placed in the ultrasonic pool for ultrasonic vibration for at least 20 minutes; The concentration of particulate matter in the primary sample is calculated according to the following formula: Where C is the concentration of the component to be measured in the particulate matter, in μg / m 3 ; m is the mass of the component to be measured, in μg; Q is the sampling flow rate, in m 3 / min; t is the sampling time, in min; f d is the dilution factor; Step S4: The lifting platform rotates to the automatic calibration module, which dilutes the collected primary sample concentration to obtain a pre-treated sample. When the automatic calibration module dilutes the primary sample concentration, it prepares standard solutions with different concentration gradients through the standard solution storage unit and the automatic dilution unit to establish a standard curve for quantitative analysis of the target component in the sample. The solution conductivity monitoring unit monitors the conductivity of the sample solution in real time. When the conductivity is detected to exceed a preset threshold, the dilution ratio is automatically adjusted by monitoring the conductivity of the primary sample solution to obtain a pre-treated sample. The dilution factor f d Automatically adjust according to the conductivity of the sample solution according to the following formula: Wherein, σ is the conductivity of the primary sample solution, in mS / cm; σ0 is the preset conductivity threshold, σ0 is 2.0 mS / cm; Indicates not less than The smallest integer; Step S5, controlling the lifting and rotating stage to align the pre-treated sample with the inlet of the analytical instrument, transferring the pre-treated sample to the analytical instrument through the inlet, selecting a corresponding analytical method according to the component to be measured, and obtaining the concentration of the target component in the atmospheric particulate matter; The corresponding analysis methods are selected according to the components to be tested, including: using ICP-MS to analyze water-soluble metal elements; using ion chromatography to analyze water-soluble salts; using GC-MS to analyze the organic components of normal alkanes and polycyclic aromatic hydrocarbons; In step S6, the lifting and rotating table transfers the reagent bottles that have completed the analysis to the cleaning and sample changing position. The cleaning and sample changing position first places the new reagent bottles that have been pre-added with the corresponding solvent on the reagent bottle fixing seat, and then automatically cleans the reagent bottles that have completed the analysis. The cleaned reagent bottles are re-added with the corresponding solvent for the next round of sample collection.

8. The method for automatically collecting multi-component atmospheric particulate matter according to claim 7, characterized in that: The sampling flow rate of the particle introduction device is 16.7 L / min.

9. The method for automatically collecting multi-component atmospheric particulate matter according to claim 7, characterized in that: The frequency of the ultrasonic oscillation is 40 kHz.

10. The method for automatically collecting multi-component atmospheric particulate matter according to claim 7, characterized in that: The automatic dilution unit adopts a cooperative working mode of a microinjection pump and a peristaltic pump, controls the addition amount of the standard solution by the microinjection pump, and controls the addition amount of the dilution solvent by the peristaltic pump, thereby achieving accurate dilution of the sample and the standard solution.

Images