Method for detecting content of micro-plastics in sample to be detected

Abstract

The invention belongs to the technical field of environmental pollution detection, and particularly relates to a method for detecting the content of micro-plastics in a to-be-detected sample, which comprises the following steps: S1, acquiring the micro-plastics in the to-be-detected sample, and dyeing the micro-plastics to obtain dyed micro-plastics; s2, counting the dyed micro-plastics to obtain a counting result so as to determine the content of the micro-plastics in the to-be-detected sample; wherein a coloring agent used in the dyeing treatment is a photosensitive resin coloring agent, and the micro-plastic in the micro-plastic sample is white. According to the detection method disclosed by the invention, the micro-plastics are dyed by the photosensitive resin dyeing agent, and the color depths of the dyeing results of the micro-plastics of different materials are different, so that the composition condition of the micro-plastics in the to-be-detected sample is analyzed according to the counting result; the method has the advantages of being accurate, efficient, low in cost, suitable for various micro-plastics, small in environmental influence, high in application value and the like, and the application range is wide.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental pollution detection, and in particular relates to a method for detecting microplastic samples. Background Art

[0002] Plastics are widely used in various industries in production and life due to their easy manufacturing, low cost and stable properties. However, with the mass production and use of plastics, while bringing convenience to humans, it also leads to a large amount of waste plastics discharged into the environment. Plastic products entering the environment will be decomposed into smaller particles or flakes, of which those smaller than 5mm are called microplastics. Microplastics are widely distributed and have been detected in rivers, sediments, reservoirs, artificial wetlands and other environments. Types include polystyrene (PS), polyvinyl chloride (PVC), polycarbonate (PC), polyethylene terephthalate (PET), polyamide (PA) and polypropylene (PP), etc., posing a serious threat to the ecological environment and human health.

[0003] At present, in the study of the presence of microplastics in the environment, the detection method of microplastics is mainly based on microscopy combined with Fourier infrared spectroscopy and Raman spectroscopy analysis. However, when the sample size is too large, the above methods have problems such as complex operation, high cost, and long time consumption, which is not conducive to the rapid and accurate counting of various types of microplastics.

[0004] Therefore, it is urgent to develop an accurate, efficient, low-cost and applicable quantitative detection method for a variety of microplastics. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art to a certain extent. To this end, the present invention provides a method for detecting microplastic samples. The method for detecting microplastic samples of the present invention has the advantages of accuracy, high efficiency, low cost, applicability to a variety of microplastics, low impact on the environment, high application value, and a wide range of applications.

[0006] In the first aspect of the present invention, the present invention proposes a method for detecting the content of microplastics in a sample to be tested. According to an embodiment of the present invention, the following steps are included: S1: obtaining microplastics in the sample to be tested, dyeing the microplastics to obtain dyed microplastics; S2: counting the dyed microplastics to obtain counting results to determine the content of microplastics in the sample to be tested; wherein the dye used in the dyeing process is a photosensitive resin dye, and the microplastics in the sample to be tested are white. According to the detection method of an embodiment of the present invention, microplastics are dyed by photosensitive resin dyes, and the color depth of the dyeing results of microplastics of different materials is different, so that the composition of microplastics in the sample to be tested is analyzed by counting results, which has the advantages of accuracy, high efficiency, low cost, applicability to a variety of microplastics, low impact on the environment and high application value, and has a wide range of applications.

[0007] According to an embodiment of the present invention, the above-mentioned method for detecting microplastic samples may also have the following additional technical features:

[0008] According to an embodiment of the present invention, the working concentration of the dye is determined according to the following standards: (1) it can successfully dye the microplastics in the sample to be tested; (2) there is a color difference in the dyeing results between microplastics of different materials in the sample to be tested.

[0009] According to an embodiment of the present invention, the dye includes one or more of a blue photosensitive resin dye, a red photosensitive resin dye, and a green photosensitive resin dye.

[0010] According to a specific embodiment of the present invention, the dye is a blue photosensitive resin dye.

[0011] According to an embodiment of the present invention, the microplastics of the sample to be tested include one or more of polystyrene, polyvinyl chloride, polycarbonate, polyethylene terephthalate, polyamide and polypropylene.

[0012] According to a specific embodiment of the present invention, the materials to be tested include polypropylene, polystyrene and polyvinyl chloride.

[0013] In the second aspect of the present invention, the present invention proposes a method for quantitatively analyzing the amount of microplastics adsorbed by a solid phase matrix. According to a specific embodiment of the present invention, the following steps are included: A. Take samples containing microplastics before and after solid phase matrix adsorption, perform digestion treatment I, and collect samples after digestion treatment I respectively; B. Detect the samples after digestion treatment I according to the detection method of the first aspect to obtain counting results; C. Combine the counting results and perform quantitative analysis. According to the method of the embodiment of the present invention, by digesting and filtering the samples containing microplastics before and after solid phase matrix adsorption, obtain the samples after digestion treatment I, and then detect and quantitatively analyze them according to the detection method described in the first aspect, the quantitative detection of the microplastic adsorption capacity of the solid phase matrix is ​​realized. The method has the advantages of being quantitative, accurate, efficient, low-cost, applicable to a variety of microplastics, having little impact on the environment and high application value, and is applicable to a variety of application scenarios.

[0014] According to an embodiment of the present invention, the above method for quantitatively analyzing the amount of microplastics adsorbed by a matrix may also have the following additional technical features:

[0015] According to an embodiment of the present invention, the digestion solution used in the digestion treatment I includes one or more of hydrogen peroxide, nitric acid, perchloric acid and sulfuric acid.

[0016] In the third aspect of the present invention, the present invention proposes a method for quantitatively analyzing microplastics in a solid matrix. According to an embodiment of the present invention, the following steps are included: a. Take solid matrix samples of different depths, perform digestion treatment II, and collect samples of different depths after digestion treatment II respectively; b. Detect the samples of different depths after digestion treatment II according to the aforementioned detection method to obtain counting results; c. Combine the counting results and perform quantitative analysis. According to the method of an embodiment of the present invention, by digesting and filtering solid matrix samples of different depths, samples after digestion treatment II are obtained, and then the samples are detected and data analyzed according to the detection method described in the first aspect, so as to achieve quantitative detection of the ability of solid matrix samples to remove microplastics, etc. The method has the advantages of being quantitative, accurate, efficient, low-cost, applicable to a variety of microplastics, having little impact on the environment, and having high application value, and is applicable to a variety of solid matrix environments.

[0017] According to an embodiment of the present invention, the above-mentioned method for quantitatively analyzing microplastics in soil may also have the following additional technical features:

[0018] According to an embodiment of the present invention, the digestion solution used in the digestion treatment II includes one or more of hydrogen peroxide, nitric acid, perchloric acid and sulfuric acid.

[0019] According to an embodiment of the present invention, the solid matrix includes soil and / or artificial wetland filler.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0022] Figure 1 The figures are the dyeing results of different types of microplastics in Example 1 of the present invention, wherein (a) from left to right are the dyeing results of fragmented PS, PC, PET, PVC and PA diluted 5 times in red photosensitive resin dye, (b) from left to right are the dyeing results of fragmented PS, PC, PET, PVC and PA diluted 10 times in red photosensitive resin dye, (c) from left to right are the dyeing results of fragmented PS, PC, PET, PVC and PA diluted 5 times in blue photosensitive resin dye, (d) from left to right are the dyeing results of fragmented PS, PC, PET, PVC and PA diluted 5 times in green photosensitive resin dye, (e) from left to right are the dyeing results of fragmented PP and the morphology of microbeaded PS;

[0023] Figure 2 This is a schematic diagram of a device for simulating vertical flow and artificial wetland in Example 1 of the present invention;

[0024] Figure 3 The removal of PP, PS, and PVC microplastics by the simulated artificial wetland in Example 1 of the present invention (outlet). Among them, (a) is the result diagram of MPs abundance / removal rate in the effluent of VFCW1, (b) is the result diagram of MPs abundance / removal rate in the effluent of VFCW2, and (c) is the result diagram of MPs abundance / removal rate in the effluent of VFCW3;

[0025] Figure 4 This is the vertical distribution (matrix) of PP, PS, and PVC microplastics in the simulated artificial wetland in Example 1 of the present invention, wherein (a) is the result diagram of the MPs abundance in the VFCW1 matrix, (b) is the result diagram of the MPs abundance in the VFCW2 matrix, and (c) is the result diagram of the MPs abundance in the VFCW3 matrix. DETAILED DESCRIPTION

[0026] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0027] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. Further, in the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0028] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0029] In this document, the terms “include” or “comprising” are open expressions, that is, including the contents specified in the present invention but not excluding other contents.

[0030] As used herein, the terms "optionally", "optional" or "optionally" generally mean that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0031] Detection method of microplastic content in samples to be tested

[0032] The present invention proposes a method for detecting the content of microplastics in a sample to be tested. According to an embodiment of the present invention, the following steps are included: S1: obtaining microplastics in the sample to be tested, dyeing the microplastics to obtain dyed microplastics; S2: counting the dyed microplastics to obtain counting results to determine the content of microplastics in the sample to be tested; wherein the dye used in the dyeing process is a photosensitive resin dye, and the microplastics in the sample to be tested are white. According to the detection method of an embodiment of the present invention, microplastics are dyed by photosensitive resin dyes, and the color depth of the dyeing results of microplastics of different materials is different, so that the composition of microplastics in the sample to be tested is analyzed by counting results, which has the advantages of accuracy, high efficiency, low cost, applicability to a variety of microplastics, low environmental impact and high application value, and has a wide range of applications. Exemplarily, the sample to be tested includes water samples, soil samples, wetland filler samples, etc.

[0033] According to an embodiment of the present invention, the working concentration of the dye is determined according to the following criteria: (1) the microplastics in the sample to be tested can be successfully dyed; (2) there is a color difference in the dyeing results between microplastics of different materials in the sample to be tested. Thus, the working concentration of the dye is determined so that microplastics of different materials can be successfully dyed and distinguished and counted.

[0034] According to an embodiment of the present invention, the dye includes one or more of a blue photosensitive resin dye, a red photosensitive resin dye, and a green photosensitive resin dye. Thus, the photosensitive resin dye can be used to dye microplastics of different materials, and the dyeing conditions can be used to help distinguish microplastics of different materials.

[0035] According to a specific embodiment of the present invention, the dye is a blue photosensitive resin dye. Therefore, when the dye is a blue photosensitive resin dye, the dyeing distinction of microplastics of different materials is more obvious, further improving the resolution efficiency of distinguishing microplastics of different materials.

[0036] According to an embodiment of the present invention, the microplastics of the sample to be tested include one or more of polystyrene, polyvinyl chloride, polycarbonate, polyethylene terephthalate, polyamide and polypropylene. Therefore, the detection method of the present invention is applicable to the detection of a variety of microplastics.

[0037] According to a specific embodiment of the present invention, the samples to be tested include polypropylene, polystyrene and polyvinyl chloride. Therefore, when the dye is a blue photosensitive resin dye, the difference in the dyeing results of polypropylene, polystyrene and polyvinyl chloride microplastics is most obvious, and the resolution efficiency is relatively high.

[0038] Method for quantitative analysis of microplastic adsorption on solid matrix

[0039] The present invention proposes a method for quantitatively analyzing the amount of microplastics adsorbed by a solid phase matrix. According to a specific embodiment of the present invention, the following steps are included: A. taking samples containing microplastics before and after adsorption by the solid phase matrix, performing digestion treatment I, and collecting samples after digestion treatment I respectively; B. testing the samples after digestion treatment I respectively according to the aforementioned detection method to obtain counting results; C. combining the counting results, performing quantitative analysis. According to the method of the embodiment of the present invention, by performing digestion treatment and filtering on the samples containing microplastics before and after adsorption by the solid phase matrix, obtaining the samples after digestion treatment I, and then testing and data analysis on the samples according to the aforementioned detection method, quantitative detection of the microplastic adsorption capacity of the solid phase matrix is ​​achieved. Exemplarily, the solid phase matrix includes soil, artificial wetland filler, etc. The method has the advantages of being quantitative, accurate, efficient, low-cost, applicable to a variety of microplastics, having little impact on the environment, and having high application value, and is applicable to a variety of application scenarios.

[0040] According to an embodiment of the present invention, the digestion solution used in the digestion treatment I includes one or more of hydrogen peroxide, nitric acid, perchloric acid and sulfuric acid. Thus, the sample is treated with the digestion solution to remove organic matter and dissolved particles in the sample, and combined with the filtration treatment, only the microplastics required for detection are retained, further improving the accuracy of the quantitative analysis of the amount of microplastic adsorption of the matrix.

[0041] Quantitative analysis of microplastics in solid matrix

[0042] The present invention proposes a method for quantitatively analyzing microplastics in a solid matrix. According to an embodiment of the present invention, the following steps are included: a. taking solid matrix samples of different depths, performing digestion treatment II, and collecting samples of different depths after digestion treatment II respectively; b. testing the samples of different depths after digestion treatment II according to the aforementioned detection method to obtain counting results; c. combining the counting results, performing quantitative analysis. According to the method of an embodiment of the present invention, by performing digestion treatment and filtering on solid matrix samples of different depths, samples of different depths after digestion treatment II are obtained, and then the samples are tested and data analyzed according to the aforementioned detection method, so as to achieve quantitative detection of the ability of solid matrix samples to remove microplastics, etc., illustratively, the solid matrix samples include soil samples of different depths, artificial wetland filler samples of different depths, etc. The method has the advantages of quantitative, accurate, efficient, low cost, applicable to a variety of microplastics, small impact on the environment and high application value, and is applicable to a variety of application scenarios.

[0043] According to an embodiment of the present invention, the digestion solution used in the digestion treatment II includes one or more of hydrogen peroxide, nitric acid, perchloric acid and sulfuric acid. Thus, the sample is treated with the digestion solution to remove organic matter and dissolved particles in the sample, and combined with the filtration treatment, only the microplastics required for detection are retained, further improving the accuracy of the quantitative analysis of the amount of microplastic adsorption of the matrix.

[0044] According to an embodiment of the present invention, the solid matrix includes soil and / or artificial wetland filler. Therefore, the detection method for quantitatively analyzing microplastics in a solid matrix is ​​suitable for different application scenarios and has a wide range of applications.

[0045] The scheme of the present invention will be explained below in conjunction with the embodiments. It will be appreciated by those skilled in the art that the following embodiments are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. Where specific techniques or conditions are not indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used are not indicated by the manufacturer and are all conventional products that can be obtained commercially.

[0046] Example 1: Quantitative analysis of the removal and distribution of various microplastics in constructed wetlands

[0047] 1. Exploration of microplastic dyes

[0048] The inventor spent a lot of time in the early stage exploring and researching suitable microplastic dyes, examining conditions including dyeing effect, price, etc., and finally chose photosensitive resin dye as the microplastic dye for subsequent experiments.

[0049] 2. Confirmation of the optimal staining conditions for microplastics and the most suitable microplastic types

[0050] White fragmented PS, PVC, PET, PA, PP and beaded PS microplastics of 75 to 150 μm were selected and dyed with red, blue and green photosensitive resin dyes (purchased from Tianjin Manhua Technology Co., Ltd.), respectively, and the color difference method was used to confirm the optimal dyeing conditions.

[0051] According to the instructions of the dye, the red photosensitive resin dye was first used to conduct a microplastic dyeing dilution multiple confirmation experiment, and the dyeing time was 5 minutes. At different dilution multiples, the red dye was used to dye PS, PVC, PC, PET, PP, and PA type microplastics. The red photosensitive resin dye diluted 5 times and 10 times had almost no effect on PP type microplastics ( Figure 1 (e) in which PS microplastics showed a light red color under 5-fold dilution staining conditions ( Figure 1 (a)), while the color is lighter under the 10-fold dilution staining condition ( Figure 1 (b) in the figure is difficult to distinguish from PP microplastics, so a 5-fold dilution factor is selected for the next dye color selection experiment, and the dyeing time is still 5 minutes. Blue and green photosensitive resin dyes are selected for further dyeing to select the appropriate dye color. Since PP type microplastics are almost colorless in red photosensitive resin dyes, PS, PC, PET, PVC, and PA microplastics are selected for dyeing in blue and green photosensitive resin dyes at a 5-fold dilution factor ( Figure 1 In (c), the blue photosensitive resin dye diluted 5 times effectively dyes PS and PVC type microplastics and can be identified by color difference. The green photosensitive resin dye diluted 5 times has a lighter color on PS type microplastics, which is not easy to identify ( Figure 1 (d) in the figure). Since the blue color makes the image clearer under the microscope, and PP, PS, and PVC can appear in three colors: colorless, light, and dark in the dye, blue dye and PP, PS, and PVC microplastics were selected as the next experimental materials.

[0052] The dyeing results of different types of microplastics are shown in Figure 1 .

[0053] The results showed that the optimal dyeing condition was to dilute the blue photosensitive resin dye 5 times and then dye for 5 minutes; the most suitable microplastic types were PP, PS, and PVC. Under this condition, PP was colorless, PS was light-colored, and PVC was dark-colored.

[0054] 3. Collection and treatment of microplastics in simulated artificial wetland effluent

[0055] Simulated vertical flow constructed wetlands (VFCW) 1-3 were constructed, where VFCW1 was filled with 0.3-0.6 cm fine gravel; VFCW2 was filled with 1-1.5 cm coarse gravel; VFCW3 was filled with 456 μm coarse sand; and then a stainless steel micro spoon (volume about 1.5 mm2) was added to the water inlet of each device every 2 days. 3 ) of PP (fragmented, 379±23 pieces), PS (fragmented, 403±35 pieces), PS (microbeads, 462±21 pieces) and PVC (fragmented, 432±27 pieces) microplastics. 1L of water sample was collected at the outlet every 2 days. The experimental period was 30 days. The microplastics in the water were collected on the surface of 0.45μm glass fiber filter membrane by vacuum filtration, and then rinsed into a 50mL beaker with deionized water to obtain some microplastic samples at the outlet.

[0056] Schematic diagram of simulated vertical flow artificial wetland device Figure 2 .

[0057] 4. Collection and treatment of microplastics in simulated artificial wetland matrix

[0058] The matrix ( Figure 2 The filling layer e and the supporting layer f in the simulation device shown are divided into 7 layers (from top to bottom), namely 0-3 cm, 3-6 cm, 6-9 cm, 9-14 cm, 14-19 cm, 19-24 cm, and 24-30 cm. They are taken out layer by layer from top to bottom, placed in a beaker and added with 20 mL of H2O2 (concentration of 30%) to digest the surface organic matter. At the same time, a glass rod is used for stirring, and then a stainless steel mesh with stacked pore sizes of 150 μm and 75 μm is used to filter and collect microplastics in the range of 75-150 μm. After rinsing, they are placed in a 50 mL beaker to obtain a matrix part microplastic sample.

[0059] 5. Microplastic staining and counting

[0060] The microplastic samples from the outlet obtained in step 3 and the microplastic samples from the matrix collected from the matrix at different heights in step 4 were dyed with a 5-fold diluted blue photosensitive resin dye. After 5 minutes, the blue photosensitive resin dye was washed off, the microplastics were collected by filtration, and the PP (fragmented), PS (fragmented), PS (microbeaded) and PVC (fragmented) microplastics were counted using a five-point counting method under a microscope.

[0061] The five-point counting method was used to quantitatively analyze and calculate microplastics. In the effective filtration area of ​​the filter membrane, five square areas, namely the upper, left, middle, right, and lower areas, were selected for visual inspection under a microscope. The side length of the square area was 5 mm, and the number of microplastics N in each square area was counted by visual inspection. i , the total number of microplastics Ntotal is calculated according to formula (1).

[0062]

[0063] In formula (1): Stotal is the effective filtration area of ​​the membrane, Stotal = 1256 mm 2 , S quadrat is the area of ​​each square area, S quadrat = 25mm 2 .

[0064] The results of microplastic counting using the five-point counting method are shown in Table 1.

[0065] Table 1 Microplastic counting results in VFCW1 / 2 / 3

[0066]

[0067]

[0068] The counting results of microplastics in VFCW1 / 2 / 3 showed that the average recovery rate of microplastics was 70.66% to 81.30%, among which the recovery rate of fragmented PP type microplastics was lower, which may be related to the wall adhesion phenomenon or the uneven distribution of microplastics on the filter membrane.

[0069] 6. Comprehensive analysis of the removal and distribution of various types of microplastics

[0070] According to the results of counting PP (fragmented), PS (fragmented), PS (microbeaded) and PVC (fragmented) microplastics in step 5, the abundance and removal rate of microplastics in the effluent of the simulated artificial wetland were calculated, and the influence of the artificial wetland matrix on the removal of microplastics and the vertical distribution of microplastics in the simulated artificial wetland were explored. The microplastic recovery rate was calculated as follows: after the experiment, the number of microplastics in the effluent and matrix of the artificial wetlands VFCW1 to VFCW3 was calculated and compared with the number of microplastics in the influent to obtain the recovery rate of microplastics in each artificial wetland:

[0071] Recovery rate (%) = (total number of microplastics in the matrix + total number of microplastics in the effluent) / (total number of microplastics in the influent) 100%; removal rate of microplastics by the matrix (%) = (total number of microplastics in the effluent) / (total number of microplastics in the influent) * 100%.

[0072] The removal of PP, PS and PVC microplastics by simulated artificial wetlands (outlet) is shown in Figure 3 .

[0073] The vertical distribution of PP, PS and PVC microplastics in simulated artificial wetlands (matrix) is shown in Figure 4 .

[0074] The results showed that the total removal efficiency of microplastics by coarse sand (456 μm), fine gravel (0.3-0.6 cm), and coarse gravel (1-1.5 cm) was 100%, 96.45%, and 93.55%, respectively. Microplastics failed to flow out of VFCW3 with coarse sand as the matrix, and reached a maximum depth of 14 cm, with a recovery rate of up to 90%; in VFCW1, microplastics showed a decreasing vertical distribution pattern, and in VFCW2, microplastics were most distributed in the second layer (3-6 cm) at depth.

[0075] The above results show that the matrix particle size plays a vital role in the removal efficiency of microplastics. In addition, microplastics are mostly concentrated in the middle and upper layers of wetlands, and reducing the matrix particle size can effectively improve the interception effect of artificial wetlands on microplastics.

[0076] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0077] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for detecting the content of microplastics in a sample to be tested, characterized in that: The following steps are involved: S1: obtaining microplastics in the sample to be tested, and dyeing the microplastics to obtain dyed microplastics; S2: Counting the dyed microplastics to obtain a counting result to determine the content of microplastics in the sample to be tested; Among them, the dye used in the dyeing treatment is a photosensitive resin dye, and the microplastics in the sample to be tested are white.

2. The detection method according to claim 1, characterized in that: The working concentration of the dye is determined according to the following standards: (1) The microplastics in the sample to be tested can be successfully dyed; (2) There is color difference in the dyeing results between microplastics of different materials in the sample to be tested.

3. The detection method according to claim 1, characterized in that: The dye comprises one or more of a blue photosensitive resin dye, a red photosensitive resin dye and a green photosensitive resin dye; Optionally, the dye is a blue photosensitive resin dye.

4. The detection method according to claim 1, characterized in that: The microplastics in the sample to be tested include one or more of polystyrene, polyvinyl chloride, polycarbonate, polyethylene terephthalate, polyamide and polypropylene.

5. The detection method according to claim 3, characterized in that: The samples to be tested include polypropylene, polystyrene and polyvinyl chloride.

6. A method for quantitatively analyzing the amount of microplastics adsorbed by a solid matrix, characterized in that: The following steps are involved: A. Take samples containing microplastics before and after solid matrix adsorption, perform digestion treatment I, and collect samples after digestion treatment I; B. testing the samples after digestion treatment I according to the detection method according to any one of claims 1 to 5 to obtain counting results; C. Combine the counting results and perform quantitative analysis.

7. The method according to claim 6, characterized in that The digestion solution used in the digestion treatment I includes one or more of hydrogen peroxide, nitric acid, perchloric acid and sulfuric acid.

8. A method for quantitatively analyzing microplastics in a solid matrix, characterized in that: The following steps are involved: a. Take solid matrix samples at different depths, perform digestion treatment II, and collect samples at different depths after digestion treatment II; b. The samples after digestion treatment II at different depths are tested according to the detection method according to any one of claims 1 to 5 to obtain the counting results; c. Perform quantitative analysis based on the counting results.

9. The detection method according to claim 8, characterized in that: The digestion solution used in the digestion treatment II includes one or more of hydrogen peroxide, nitric acid, perchloric acid and sulfuric acid.

10. The detection method according to claim 8, characterized in that: The solid matrix includes soil and / or artificial wetland filler.

Images