Efficient water and soil sample micro-plastic separation and concentration device and use method thereof

Abstract

The invention relates to the field of micro-plastic detection, in particular to a water and soil sample micro-plastic separation and concentration device and method. An efficient water and soil sample micro-plastic separation and concentration device comprises a funnel, a rubber plug, a bottle body and a micro vacuum pump, and is characterized in that the funnel comprises a containing part, an upper conveying pipe, an upper connecting part, a filter membrane tray, a sealing rubber ring, a lower connecting part, a lower conveying pipe and a KF16 vacuum clamp; the upper end of the accommodating part is provided with an opening for injecting a to-be-treated sample, and the lower end of the accommodating part is fixedly connected with the upper end of the upper conveying pipe; the lower end of the upper conveying pipe is fixedly connected with the upper end of the upper connecting part; and the lower end of the lower connecting part is fixedly connected with the upper end of the lower conveying pipe. According to the invention, the sample introduction process is effectively simplified, one-time efficient introduction of the sample is realized, the integrity and representativeness of the sample are ensured while the analysis efficiency is remarkably improved, and the method has the advantages of simplicity and convenience in operation, good reproducibility, high detection accuracy and the like.

Description

Technical Field

[0001] This invention relates to the field of microplastic detection, and in particular to a device and method for separating and concentrating microplastics in soil and water samples based on a thermal pyrolysis gas chromatography-mass spectrometry instrument. Background Technology

[0002] Microplastics, typically referring to plastic particles with a diameter of less than 5 mm, have become a new type of environmental pollutant that has attracted widespread attention globally. Plastic products, due to their low cost and superior performance, are widely used in packaging, textiles, and daily consumer goods. However, they are difficult to degrade naturally in the environment, leading to the continuous accumulation and breakdown of large amounts of plastic waste into microplastics. It is predicted that the total amount of global plastic waste will rise to approximately 270 million tons by 2060. Microplastics are characterized by their reluctance to degrade, large specific surface area, and high mobility. Their occurrence, migration, transformation patterns, and ecological effects in environmental media are far more complex than those of traditional pollutants. Furthermore, microplastics can interact with other pollutants in the environment, further increasing their potential risks to ecosystems and human health. Therefore, establishing accurate and reliable qualitative and quantitative methods for microplastics is a crucial foundation for scientifically assessing their environmental behavior and ecological effects, and an important prerequisite for deeply understanding their toxic mechanisms and constructing an environmental risk early warning system.

[0003] Qualitative and quantitative analysis of microplastics mainly employs three methods: microscopic analysis, spectroscopic analysis, and mass spectrometry. Microscopic analysis can qualitatively and statistically determine the type and quantity of microplastics, but it struggles to directly obtain their mass information. Spectroscopic analysis has low sensitivity for detecting microplastic particles smaller than 5 μm and faces difficulties in identifying composite particles with spectral similarity below 50%, similarly unable to directly determine the mass of microplastics. In contrast, pyrolysis gas chromatography-mass spectrometry combines qualitative and quantitative analysis capabilities, offering advantages such as low background interference, high detection sensitivity, and the ability to test submicron particle sizes. It accurately identifies polymer types and quantifies trace microplastics through characteristic pyrolysis products, and can also effectively analyze additives and degradation products contained in microplastics, providing strong technical support for the remediation and control of microplastic pollution.

[0004] Microplastic analysis methods based on pyrolysis gas chromatography-mass spectrometry mainly employ two modes: liquid injection and solid injection. While liquid injection allows for the complete introduction of the sample, the pretreatment process requires multiple solvent evaporations, resulting in cumbersome, time-consuming, and inefficient operations. Furthermore, trace amounts of the target analyte are easily lost during these multiple transfers. For example, Chinese patent application CN202510126885.8 (publication date: January 27, 2025) discloses a method for simultaneously detecting multiple microplastics in water. This method uses liquid injection and requires multiple sample transfers and heating to concentrate the sample until the solvent is completely evaporated, resulting in a lengthy process and easy loss of the target analyte. Another example is Chinese patent application CN202411249988.5 (publication date: September 6, 2024), which discloses an analytical method for micro- and nano-plastics in biological fluids. This method, also based on liquid injection, requires heating at 100–150°C to volatilize the sample matrix, making the operation complex and posing a potential degradation risk to thermally unstable polymers. Solid injection typically requires co-grinding the sample with a matrix such as calcium carbonate to achieve uniform dispersion, but the true homogeneity of the sample after grinding is difficult to guarantee, and partial injection leads to insufficient sample representativeness and poor reproducibility of analytical results. In addition, this method requires a large sample volume and is only suitable for high-concentration, controllable microplastic samples in the laboratory, making it difficult to meet the high-sensitivity detection requirements of trace microplastics in real-world environmental samples.

[0005] Therefore, there is an urgent need to establish a high-efficiency microplastic separation and concentration device for soil and water samples based on thermal pyrolysis gas chromatography-mass spectrometry and its application method. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a water and soil sample microplastic separation and concentration device and its usage method that is easy to operate, has high sample injection efficiency, and excellent detection accuracy.

[0007] The technical solution adopted in this invention is as follows: a high-efficiency microplastic separation and concentration device for soil and water samples, comprising a funnel, a rubber stopper, a bottle body, and a micro vacuum pump. The funnel includes a receiving part, an upper delivery pipe, an upper connecting part, a filter membrane tray, a sealing rubber ring, a lower connecting part, a lower delivery pipe, and a KF16 vacuum clamp. The upper end of the receiving part has an opening for injecting the sample to be processed, and its lower end is fixedly connected to the upper end of the upper delivery pipe. The lower end of the upper delivery pipe is fixedly connected to the upper end of the upper connecting part. The lower end of the lower connecting part is fixedly connected to the upper end of the lower delivery pipe. The lower end of the upper connecting part and the upper end of the lower connecting part are each provided with a corresponding circular groove. The filter membrane tray has a through hole in the center, and its upper and lower end faces are respectively provided with circular flanges that mate with the circular grooves. A sealing rubber ring is fitted around the outer periphery of the filter membrane tray. The upper connecting part, the filter membrane tray, and the lower connecting part are detachably and sealed together by means of the vacuum clamp. The lower delivery pipe passes through the rubber stopper and is sealed together with the bottle body. The micro vacuum pump is connected to the bottle body to provide negative pressure.

[0008] Preferably, the receiving part is made of stainless steel and has an upper opening diameter of 2.5cm; the upper conveying pipe is made of stainless steel and has a length of 5cm; the lower conveying pipe is made of stainless steel and has a length of 7cm; both have an outer diameter of 0.3cm; the vacuum clamp is made of stainless steel and has an inner diameter of 1.6cm and an outer diameter of 3cm.

[0009] Preferably, the upper connecting part is made of stainless steel, and has a through hole with a diameter of 0.3cm and a depth of 0.3cm in the center. Its upper outer diameter is 1.5cm and its lower outer diameter is 3cm, and its sidewall is conical with an included angle of 10°~15°. The lower connecting part is made of stainless steel, and has a through hole with a diameter of 0.3cm and a depth of 0.3cm in the center. Its upper outer diameter is 3cm and its lower outer diameter is 1.5cm, and its sidewall is conical with an included angle of 10°~15°. The circular grooves at the lower end of the upper connecting part and the upper end of the lower connecting part have a diameter of 1.2cm and a depth of 0.2cm.

[0010] Preferably, the filter membrane tray is made of stainless steel, with a diameter of 1.5cm and a thickness of 0.5cm; the circular flanges on its upper and lower end faces have a diameter of 1.2cm and a height of 0.2cm; the through hole in the center of the filter membrane tray has a diameter of 0.3cm and a depth of 0.9cm, and a filter sand core is provided in the through hole; an annular groove is formed on the outer periphery of the filter membrane tray, and the sealing rubber ring is embedded in the groove, with an outer diameter of 2.5cm and a thickness of 0.5cm.

[0011] Preferably, the lower delivery tube extends into the bottle body through the rubber stopper, and its lower opening is lower than the air extraction port provided on the bottle body; the micro vacuum pump is connected to the bottle body through this air extraction port.

[0012] A separation method for a high-efficiency microplastic separation and concentration device for soil and water samples includes the following steps: Step 1: Sample pretreatment: After air-drying the soil sample, pass it through a 5mm stainless steel sieve. Transfer the sieved soil sample into a 250ml beaker, add a glass stir bar and 150ml of saturated zinc chloride solution as the flotation solution. Seal the beaker with aluminum foil and place it in a magnetic stirrer to stir thoroughly for 10 minutes. After standing for 12 hours, collect the supernatant. Repeat the above flotation operation twice by adding saturated zinc chloride solution. This step can be skipped for water samples. Step 2: After filtering the soil supernatant and water sample through a stainless steel filter membrane, transfer them to a clean beaker; then add sufficient ferrous sulfate solution to the beaker to completely submerge the filter membrane, and seal it with aluminum foil; after sonicating the sample for 30 min, add 30% hydrogen peroxide and 0.054 mol / L ferrous sulfate solution at a volume ratio of 3:1 to carry out Fenton digestion reaction on the sample; Step 3: Place the 1.2cm diameter glass fiber filter membrane on the filter membrane tray; the pore size should be the same as or smaller than that of the stainless steel filter membrane. Then assemble the funnel, rubber stopper, bottle body, micro vacuum pump, and collection device into the microplastic separation and concentration device. Open the aluminum foil paper, add the digested sample to the upper opening of the receiving part, start the micro vacuum pump, and let the sample flow into the bottle body through the filter membrane under negative pressure. Step 4: Open the microplastic separation and concentration device, and cut the glass fiber filter membrane that carries the sample after filtration. Place the filter membrane on the stainless steel filter membrane for further cutting. Step 5: Fold the cut glass fiber filter membrane in half and place it into a pyrolysis cup for subsequent analysis using a pyrolysis gas chromatography-mass spectrometer.

[0013] Preferably, the cutting opening specifications of the cutter for the glass fiber filter membrane must simultaneously satisfy formulas I and II: ; In the formula: m 样品 The mass of the sample to be tested is expressed in milligrams (mg). D is the opening diameter of the filter membrane cutter, in centimeters (cm). d is the diameter of the pyrolysis cup opening, in centimeters (cm). h represents the thickness of the filter membrane, in millimeters (mm). ρ is the density of the filter membrane, expressed in grams per cubic centimeter (g / cm³). 3 .

[0014] Preferably, the separation method is used for sample pretreatment in a pyrolysis-gas chromatography-mass spectrometry system to characterize microplastic concentration; the separation method is coupled with a microplastic analysis instrument, which includes a Fourier transform micro-infrared spectrometer for characterizing the abundance of microplastics in the 20μm-5mm range, a laser infrared imaging system for characterizing the abundance of microplastics in the 10μm-500μm range, a single-particle inductively coupled plasma mass spectrometer for characterizing the abundance of microplastics in the 600nm-20μm range, and a submicron resolution infrared Raman microscopy system for characterizing the abundance of microplastics in the 500nm-5mm range, thereby achieving comprehensive characterization of different indicators and particle sizes of microplastics.

[0015] Preferably, the pore size of the stainless steel filter membrane is determined according to the detection limit of the coupled analytical techniques: the detection limit of microplastic particles for Fourier transform micro-infrared spectrometer is 20 μm, the detection limit of microplastic particles for laser infrared imaging system is 10 μm, the detection limit of microplastic particles for single-particle inductively coupled plasma mass spectrometry is 0.6 μm, and the detection limit of microplastic particles for submicron resolution infrared Raman microscopy is 0.5 μm. Stainless steel filter membranes with pore sizes of 20 μm, 10 μm, 0.6 μm, and 0.5 μm are selected for corresponding processing.

[0016] Preferably, the pore size of the stainless steel filter membrane is determined according to the target particle size range: when studying a specific particle size distribution, the filter membrane pore size is one or more combinations of 500μm, 300μm, 20μm, 10μm, 0.6μm, 0.5μm, 0.45μm and 0.22μm to achieve segmented filtration.

[0017] The beneficial effects obtained by this invention are as follows: This invention effectively simplifies the sample introduction process, realizes efficient one-time sample introduction, significantly improves analysis efficiency, and ensures the integrity and representativeness of the sample. It has the advantages of simple operation, good reproducibility, and high detection accuracy. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the separation and concentration device of the present invention; Figure 2 This is a flowchart of the concentration and separation method of the present invention.

[0019] The markings in the attached diagram have the following meanings: 1. Funnel, 2. Rubber stopper, 3. Bottle body, 4. Miniature vacuum pump, 11. Container, 12. Upper delivery pipe, 12. Upper connection, 14. Filter membrane tray, 15. Sealing rubber ring, 16. Lower connection, 17. Lower delivery pipe, 18. Vacuum clamp. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] like Figure 1-2 As shown, the high-efficiency microplastic separation and concentration device for soil and water samples based on pyrolysis gas chromatography-mass spectrometry includes: a funnel 1, a rubber stopper 2, a bottle body 3, and a micro vacuum pump 4. The funnel 1 includes a receiving part 11, an upper delivery tube 12, an upper connecting part 13, a filter membrane tray 14, a sealing rubber ring 15, a lower connecting part 16, a lower delivery tube 17, and a KF16 vacuum clamp 18.

[0022] The receiving part 11 is made of stainless steel, with an upper opening diameter of 2.5cm and a lower connection diameter of 0.3cm where it connects to the upper conveying pipe 12. The receiving part 11 and the upper conveying pipe 12 are fixedly connected. The upper conveying pipe 12 is made of stainless steel and is 5cm long; the lower conveying pipe 17 is made of stainless steel and is 7cm long. Both have an outer diameter of 0.3cm. The upper connecting part 13 is made of stainless steel and has a through hole with a diameter of 0.3 cm and a depth of 0.3 cm in the center. Its upper outer diameter is 1.5 cm, and its lower outer diameter is 3 cm. Its sidewalls are conical with an included angle of 10° to 15°. The lower connecting part 16 is also made of stainless steel and has a through hole with a diameter of 0.3 cm and a depth of 0.3 cm in the center. Its upper outer diameter is 3 cm, and its lower outer diameter is 1.5 cm. Its sidewalls are conical with an included angle of 10° to 15°. The circular grooves at the lower ends of the upper connecting part 13 and the upper ends of the lower connecting part 16 have a diameter of 1.2 cm and a depth of 0.2 cm. The upper and lower connecting parts are fixedly connected to the upper and lower conveying pipes, respectively. The filter membrane tray 14 is made of stainless steel, with a diameter of 1.5cm and a thickness of 0.5cm. The circular flanges on its upper and lower ends have a diameter of 1.2cm and a height of 0.2cm. The through hole in the center of the filter membrane tray 14 has a diameter of 0.3cm and a depth of 0.9cm, and a filter sand core is installed inside the hole. An annular groove is formed on the outer periphery of the filter membrane tray 14, and a sealing rubber ring 15 is embedded in this groove, with an outer diameter of 2.5cm and a thickness of 0.5cm. The KF16 vacuum clamp 18 is made of stainless steel, with an inner diameter of 1.6cm and an outer diameter of 3cm.

[0023] The upper connecting part 13, the filter membrane tray 14 and the lower connecting part 16 are detachably and sealed together by a KF16 vacuum clamp 18.

[0024] The bottle body 3 is provided with an air extraction port, through which the miniature vacuum pump 4 is connected to the bottle body 3. The lower delivery pipe 17 passes through the rubber stopper 2 and extends into the bottle body 3, with its lower end opening lower than the air extraction port provided on the bottle body 3.

[0025] like Figure 2As shown, a high-efficiency method for separating microplastics in soil and water samples based on pyrolysis gas chromatography-mass spectrometry is described. The separation process includes the following steps: Step 1: Sample pretreatment: After air-drying the soil sample, pass it through a 5mm stainless steel sieve. Transfer the sieved soil sample into a 250ml beaker, add a glass stir bar and 150ml of saturated zinc chloride solution as the flotation solution. Seal the beaker with aluminum foil and place it in a magnetic stirrer to stir thoroughly for 10 minutes. After standing for 12 hours, collect the supernatant. Repeat the above flotation operation twice by adding saturated zinc chloride solution. This step can be skipped for water samples.

[0026] Step 2: The soil supernatant and water sample were filtered through a 0.22 μm stainless steel filter membrane and transferred to a clean beaker. Sufficient ferrous sulfate solution was then added to the beaker to completely submerge the filter membrane, and the beaker was sealed with aluminum foil. After sonicating the sample for 30 min, a Fenton digestion reaction was initiated by adding 30% hydrogen peroxide and 0.054 mol / L ferrous sulfate solution at a volume ratio of 3:1.

[0027] Step 3: Place a 0.22μm glass fiber filter membrane with a diameter of 1.2cm on the upper part of the filter membrane tray 14 (the pore size is the same as or smaller than that of the stainless steel filter membrane). Then assemble the funnel 1, rubber stopper 2, bottle body 3 and micro vacuum pump 4 into a microplastic separation and concentration device. Open the aluminum foil paper, add the digested sample to the upper opening of the receiving part 11, start the micro vacuum pump 4, and let the sample flow into the bottle body 3 through the filter membrane under negative pressure.

[0028] Step 4: Turn on the microplastic separation and concentration device, and place the glass fiber filter membrane carrying the sample on the stainless steel filter membrane for filter membrane cutting.

[0029] Step 5: Fold the cut filter membrane in half and place it into the pyrolysis cup to complete the sample injection for subsequent analysis by pyrolysis gas chromatography-mass spectrometry.

[0030] Preferably, the bottle body in the specific embodiment is a conical bottle.

[0031] The cutting opening specifications of the glass fiber filter membrane cutter must simultaneously meet Formulas I and II: ; In the formula: m 样品 The mass of the sample to be tested is expressed in milligrams (mg). D is the opening diameter of the filter membrane cutter, in centimeters (cm). d is the diameter of the pyrolysis cup opening, in centimeters (cm). h represents the thickness of the filter membrane, in millimeters (mm). ρThe density of the filter membrane is expressed in grams per cubic centimeter (g / cm³). 3 ).

[0032] In summary, the apparatus and method provided by this invention simplify the pretreatment process compared with existing liquid injection methods, allowing the injection process to be completed in a single injection, significantly improving injection efficiency, and effectively reducing sample loss caused by multiple transfers and operations. Compared with solid injection methods, it achieves full sample injection, avoiding errors caused by uneven sample grinding and insufficient sample representativeness, thus providing better analytical reproducibility and detection accuracy.

[0033] Example 1: Method for separating microplastics in water Step 1: After filtering the water sample through a 0.22μm stainless steel filter membrane, transfer it to a clean beaker, add ferrous sulfate solution without a filter membrane, seal with aluminum foil, and sonicate for 30 minutes. Then, add 30% hydrogen peroxide and 0.054mol / L ferrous sulfate solution at a volume ratio of 3:1 to perform Fenton digestion on the sample. Step 2: Place a 0.22μm polyester fiber filter membrane (1.2cm in diameter) on top of the filter membrane tray. Then, assemble the funnel, rubber stopper, bottle body, micro vacuum pump, and collection device to form the microplastic separation and concentration system. Apparatus; Step 3: Open the aluminum foil paper, add the digested sample to the upper opening of the receiving part, start the micro vacuum pump, and let the sample flow into the bottle through the filter membrane under negative pressure; Step 4: Open the microplastic separation and concentration device, place the polyester fiber filter membrane carrying the filtered sample on the stainless steel filter membrane and cut the filter membrane. The diameter of the cut filter membrane is 0.5 cm (the diameter of the pyrolysis cup used in this application is 0.3 cm); Step 5: Fold the cut filter membrane in half and place it in the pyrolysis cup for subsequent analysis by pyrolysis gas chromatography-mass spectrometry.

[0034] Example 2: Method for separating microplastics from soil Step 1: Sample Pretreatment: After air-drying, the soil sample is passed through a 5mm stainless steel sieve. The sieved soil sample is then transferred to a 250ml beaker, and a glass stir bar and 150ml of saturated zinc chloride solution are added as flotation solution. The beaker is sealed with aluminum foil and stirred thoroughly with a magnetic stirrer for 10 minutes. After standing for 12 hours, the supernatant is collected. The saturated zinc chloride solution is replenished, and the above flotation operation is performed twice. Step 2: The soil supernatant is filtered through a 0.22μm stainless steel filter membrane and transferred to a clean beaker. Ferrous sulfate solution without a filter membrane is added. The beaker is sealed with aluminum foil and sonicated for 30 minutes. 30% hydrogen peroxide and 0.054mol / L ferrous sulfate solution are added at a volume ratio of 3:1 for Fenton digestion of the sample. Step 3: The 0.22μm... A 1.2cm diameter polyester fiber filter membrane is placed on the upper part of the filter membrane tray. Then, the funnel, rubber stopper, bottle, micro vacuum pump, and collection device are assembled into the microplastic separation and concentration device. The aluminum foil is opened, and the digested sample is added to the upper opening of the receiving part. The micro vacuum pump is started, and the sample flows into the bottle through the filter membrane under negative pressure. Step 4: The microplastic separation and concentration device is opened. The polyester fiber filter membrane carrying the filtered sample is placed on a stainless steel filter membrane and the filter membrane is cut. The diameter of the cut filter membrane is 0.5cm (the diameter of the pyrolysis cup used in this application is 0.3cm). Step 5: The cut filter membrane is folded in half and placed into the pyrolysis cup for subsequent analysis by pyrolysis gas chromatography-mass spectrometry.

[0035] Example 3: Detection of microplastics in water using a combination of Fourier transform infrared microscopy and pyrolysis gas chromatography-mass spectrometry. Step 1: After filtering the water sample through a 20μm stainless steel filter membrane, transfer it to a clean beaker (the lower limit of particle size detection for Fourier Transform Infrared Spectroscopy (FTIR) is 20μm). Add ferrous sulfate solution without the filter membrane, seal with aluminum foil, and sonicate for 30 min. Then, add 30% hydrogen peroxide and 0.054mol / L ferrous sulfate solution at a volume ratio of 3:1 to perform Fenton digestion on the sample. Step 2: Filter the digested water sample through a 0.22μm alumina filter membrane. Scan the Fourier Transform Infrared spectrum on the filter membrane to determine the type and quantity of microplastics in the sample. Then, place the alumina filter membrane under a stereo microscope to determine the shape, color, and particle size of the microplastics. Step 3: Place the alumina filter membrane in a clean beaker, add deionized water without the filter membrane, seal with aluminum foil, and sonicate. Step 4: Place the 0.22μm polyester fiber filter membrane (1.2cm in diameter) on the upper part of the filter membrane tray, and then assemble the funnel, rubber stopper, bottle, micro vacuum pump and the collection device into the microplastic separation and concentration device; open the aluminum foil paper, add the digested sample to the upper opening of the receiving part, start the micro vacuum pump, and let the sample flow into the bottle through the filter membrane under negative pressure; Step 5: Open the microplastic separation and concentration device, place the polyester fiber filter membrane carrying the filtered sample on the stainless steel filter membrane and cut the filter membrane. The diameter of the cut filter membrane is 0.8cm (the diameter of the pyrolysis cup used in this application is 0.5cm); Step 6: Fold the cut filter membrane in half and place it in the pyrolysis cup for subsequent analysis by pyrolysis gas chromatography-mass spectrometry.

[0036] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-efficiency microplastic separation and concentration device for soil and water samples, comprising a funnel, a rubber stopper, a bottle body, and a micro vacuum pump, characterized in that: The funnel includes a receiving part, an upper delivery tube, an upper connecting part, a filter membrane tray, a sealing rubber ring, a lower connecting part, a lower delivery tube, and a KF16 vacuum clamp. The receiving part has an opening at its upper end for injecting the sample to be processed, and its lower end is fixedly connected to the upper end of the upper delivery tube. The lower end of the upper delivery tube is fixedly connected to the upper end of the upper connecting part. The lower end of the lower connecting part is fixedly connected to the upper end of the lower delivery tube. The lower end of the upper connecting part and the upper end of the lower connecting part are each provided with a corresponding circular groove. The filter membrane tray has a through hole in its center, and its upper and lower end faces are respectively provided with circular flanges that mate with the circular grooves. The outer periphery of the filter membrane tray is fitted with a sealing rubber ring. The upper connecting part, the filter membrane tray, and the lower connecting part are detachably and sealed together by means of the vacuum clamp. The lower delivery tube passes through the rubber stopper and is sealed to the bottle body. The micro vacuum pump is connected to the bottle body to provide negative pressure.

2. The high-efficiency water and soil sample microplastic separation and concentration device according to claim 1, characterized in that: The receiving part is made of stainless steel and has an upper opening diameter of 2.5cm; the upper conveying pipe is made of stainless steel and has a length of 5cm; the lower conveying pipe is made of stainless steel and has a length of 7cm; both have an outer diameter of 0.3cm; the vacuum clamp is made of stainless steel and has an inner diameter of 1.6cm and an outer diameter of 3cm.

3. The high-efficiency microplastic separation and concentration device for soil and water samples according to claim 1, characterized in that: The upper connecting part is made of stainless steel and has a through hole with a diameter of 0.3cm and a depth of 0.3cm in the center. Its upper outer diameter is 1.5cm and its lower outer diameter is 3cm, and its sidewall is conical with an included angle of 10°~15°. The lower connecting part is made of stainless steel and has a through hole with a diameter of 0.3cm and a depth of 0.3cm in the center. Its upper outer diameter is 3cm and its lower outer diameter is 1.5cm, and its sidewall is conical with an included angle of 10°~15°. The circular grooves at the lower end of the upper connecting part and the upper end of the lower connecting part have a diameter of 1.2cm and a depth of 0.2cm.

4. The efficient microplastic separation and concentration device for water and soil samples according to claim 1, characterized in that: The filter membrane tray is made of stainless steel, with a diameter of 1.5cm and a thickness of 0.5cm; the circular flanges on its upper and lower ends have a diameter of 1.2cm and a height of 0.2cm; the through hole in the center of the filter membrane tray has a diameter of 0.3cm and a depth of 0.9cm, and a filter sand core is installed in the through hole; an annular groove is formed on the outer periphery of the filter membrane tray, and a sealing rubber ring is embedded in the groove, with an outer diameter of 2.5cm and a thickness of 0.5cm.

5. The high-efficiency microplastic separation and concentration device for soil and water samples according to claim 1, characterized in that: The lower delivery tube extends into the bottle body through the rubber stopper, and its lower opening is lower than the air extraction port provided on the bottle body; the micro vacuum pump is connected to the bottle body through this air extraction port.

6. The separation method of the high-efficiency water and soil sample microplastic separation and concentration device as described in any one of claims 1-5, characterized in that: Includes the following steps: Step 1: Sample pretreatment: After air-drying the soil sample, pass it through a 5mm stainless steel sieve. Transfer the sieved soil sample into a 250ml beaker, add a glass stir bar and 150ml of saturated zinc chloride solution as the flotation solution. Seal the beaker with aluminum foil and place it in a magnetic stirrer to stir thoroughly for 10 minutes. After standing for 12 hours, collect the supernatant. Repeat the above flotation operation twice by adding saturated zinc chloride solution. This step can be skipped for water samples. Step 2: The soil supernatant and water sample are filtered through a stainless steel filter membrane and then transferred to a clean beaker; Then, add sufficient ferrous sulfate solution to the beaker to completely submerge the filter membrane, and seal it with aluminum foil. After sonicating the sample for 30 minutes, add 30% hydrogen peroxide and 0.054 mol / L ferrous sulfate solution at a volume ratio of 3:1 to carry out Fenton digestion reaction on the sample. Step 3: Place the 1.2cm diameter glass fiber filter membrane on the filter membrane tray; the pore size is the same as or smaller than that of the stainless steel filter membrane. Then assemble the funnel, rubber stopper, bottle body, micro vacuum pump and collection device into the microplastic separation and concentration device. Open the aluminum foil, add the digested sample to the upper opening of the container, start the micro vacuum pump, and let the sample flow into the bottle through the filter membrane under negative pressure; Step 4: Open the microplastic separation and concentration device, and cut the glass fiber filter membrane that carries the sample after filtration. Place the filter membrane on the stainless steel filter membrane for further cutting. Step 5: Fold the cut glass fiber filter membrane in half and place it into a pyrolysis cup for subsequent analysis using a pyrolysis gas chromatography-mass spectrometer.

7. The separation method of the high-efficiency water and soil sample microplastic separation and concentration device according to claim 6, characterized in that: The cutting opening specifications of the cutter for the glass fiber filter membrane must simultaneously satisfy formulas I and II: ; In the formula: m 样品 The mass of the sample to be tested is expressed in milligrams (mg). D is the opening diameter of the filter membrane cutter, in centimeters (cm). d is the diameter of the pyrolysis cup opening, in centimeters (cm). h represents the thickness of the filter membrane, in millimeters (mm). ρ is the density of the filter membrane, expressed in grams per cubic centimeter (g / cm³). 3 .

8. The separation method of the high-efficiency water and soil sample microplastic separation and concentration device according to claim 7, characterized in that: The separation method is used for sample pretreatment in a thermal pyrolysis-gas chromatography-mass spectrometry system to characterize the concentration of microplastics. The separation method is used in conjunction with microplastic analysis instruments, which include: a Fourier transform micro-infrared spectrometer for characterizing the abundance of microplastics in the 20μm-5mm range, a laser infrared imaging system for characterizing the abundance of microplastics in the 10μm-500μm range, a single-particle inductively coupled plasma mass spectrometer for characterizing the abundance of microplastics in the 600nm-20μm range, and a submicron resolution infrared Raman microscopy system for characterizing the abundance of microplastics in the 500nm-5mm range, thereby achieving comprehensive characterization of different indicators and particle sizes of microplastics.

9. The separation method of the high-efficiency water and soil sample microplastic separation and concentration device according to claim 8, characterized in that: The pore size of the stainless steel filter membrane is determined according to the detection limit of the coupled analytical techniques: the detection limit of microplastic particles is 20 μm for Fourier transform infrared microscopy, 10 μm for laser infrared imaging system, 0.6 μm for single-particle inductively coupled plasma mass spectrometry, and 0.5 μm for submicron resolution infrared Raman microscopy. Stainless steel filter membranes with pore sizes of 20 μm, 10 μm, 0.6 μm, and 0.5 μm are selected for corresponding processing.

10. The separation method of the high-efficiency water and soil sample microplastic separation and concentration device according to claim 9, characterized in that: The pore size of the stainless steel filter membrane is determined according to the target particle size range: when studying a specific particle size distribution, the filter membrane pore size is one or more combinations of 500μm, 300μm, 20μm, 10μm, 0.6μm, 0.5μm, 0.45μm and 0.22μm to achieve segmented filtration.

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