A fluorescence-based portable microplastic rapid detection method and device

Abstract

The application discloses a kind of portable microplastics rapid detection method and device based on fluorescence, including sampling module, pre-treatment module, fluorescence detection module and control module;Sampling module is connected with pre-treatment module, and sampling module is used for the collection of microplastics in water body;Pre-treatment module is used to remove redundant impurities, retain microplastics, and specifically dye it;Fluorescence detection module is connected with pre-treatment module, and the application relates to the technical field of water quality detection.This kind of portable microplastics rapid detection method and device based on fluorescence, the portable microplastics rapid detection device, high degree of automation, can complete the qualitative and quantitative analysis task of microplastics quickly and accurately on site, avoid the time and cost overhead of sample return laboratory analysis, save time and effort, not only can effectively improve the efficiency of sample microplastic detection, but also greatly reduce the cost of sample microplastic detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water quality detection, in particular to a portable microplastic rapid detection method and device based on fluorescence. BACKGROUND

[0002] Microplastics refer to plastic films, fibers, particles and fragments with a diameter of less than 5 mm, which may be derived from the decomposition of large plastics under different environmental conditions (such as light, heat, radiation, etc.), or may be derived from plastic microbeads and other substances added in facial cleansers or toothpaste. In recent years, the detection technology for microplastics in water bodies mainly uses non-destructive in-situ analysis methods, and Fourier transform infrared spectroscopy, Raman spectroscopy and other methods are commonly used for microplastic composition identification. After combining with other detection methods (such as ultraviolet spectroscopy and scanning electron microscopy), microplastics can also be quantitatively analyzed. Some people use transmission electron microscopy (TEM) combined with energy spectrum technology to realize qualitative and quantitative analysis of microplastics in EDS mode. However, it cannot be denied that the above-mentioned technologies also have some shortcomings. For example, Fourier transform infrared spectroscopy is not sensitive to sample size and shape; Raman spectroscopy can obtain surface functional group information and local microstructure of microplastics, but only surface information can be obtained; the accuracy of transmission electron microscopy (or scanning electron microscopy)-energy spectrum analysis needs to be improved

[0003] At present, the large-scale application of fluorescence technology in microplastic detection makes it possible to make great breakthroughs in the qualitative and quantitative analysis of microplastics in water bodies. From the known results, when using fluorescence technology to detect microplastics in water bodies, this method has the advantages of strong specificity, high detection sensitivity, fast detection speed, good repeatability, etc. However, when using fluorescence technology for detection, there are still problems of low efficiency, multiple pretreatment steps, low automation degree, long detection period, difficulty in real-time qualitative and quantitative analysis of microplastics in water bodies, and unsuitability for remote monitoring. SUMMARY

[0004] (I) Technical problems solved

[0005] In view of the shortcomings of the prior art, the present application provides a portable microplastic rapid detection method and device based on fluorescence, which solves the problems of low efficiency, multiple pretreatment steps, low automation degree, long detection period, difficulty in real-time qualitative and quantitative analysis of microplastics in water bodies, and unsuitability for remote monitoring when using fluorescence technology for detection.

[0006] (II) Technical solutions

[0007] In order to achieve the above object, the present application is realized by the following technical scheme: A portable micro-plastic rapid detection device based on fluorescence, comprising a sampling module, a pretreatment module, a fluorescence detection module and a control module; the sampling module is connected with the pretreatment module, and the sampling module is used for collecting micro-plastics in water; the pretreatment module is used for removing redundant impurities, retaining micro-plastics, and performing specific staining; the fluorescence detection module is connected with the pretreatment module, a sample dyed by the pretreatment module is excited by a xenon lamp light source to make the dyed sample produce fluorescence, and a real image or a fluorescence-concentration curve is quickly generated; the control module is connected with the sampling module, the pretreatment module and the fluorescence detection module respectively, and is used for operation control of the sampling module, the pretreatment module and the fluorescence detection module and external communication.

[0008] The sampling module comprises a metering sampling pump, a sample pool, a fourth electromagnetic valve and a sampling joint, the sampling joint is connected with the on-site water body, and is used for collecting water samples; the fourth electromagnetic valve is connected with the sample pool and the sampling joint through pipelines respectively, and is used for controlling and adjusting the flow rate and pressure of water samples entering the sample pool; the sample pool is used for sample collection, and a filter membrane is lined in the sample pool, the filter membrane is made of acid-resistant plastic material, and can filter micro-plastics in water; the metering sampling pump is connected with the sample pool through a pipeline, and the metering sampling pump has different functions in different time periods, and is used for calculating and controlling the amount of water in the sample pool in a specific time.

[0009] The pre-treatment module comprises a metering sampling pump, a sample cell, a digestion agent storage tank, a first electromagnetic valve, a cleaning agent storage tank, a second electromagnetic valve, a fluorescent color developing agent storage tank and a third electromagnetic valve. The digestion agent storage tank is connected with the sample cell through the first electromagnetic valve by a pipeline and is used for storing an acidic digestion agent. The first electromagnetic valve is connected with the sample cell and the digestion agent storage tank by pipelines respectively and is used for controlling and adjusting the flow rate and pressure of the digestion agent entering the sample cell. The metering sampling pump is connected with the sample cell by a pipeline and has different functions in different time periods. In a specific time, the metering sampling pump is used for calculating and controlling the addition amount of the digestion agent in the sample cell. The cleaning agent storage tank is connected with the sample cell through the second electromagnetic valve by a pipeline and is used for storing a cleaning agent. The second electromagnetic valve is connected with the sample cell and the cleaning agent storage tank by pipelines respectively and is used for controlling and adjusting the flow rate and pressure of the cleaning agent entering the sample cell. The metering sampling pump is connected with the sample cell by a pipeline and has different functions in different time periods. In a specific time, the metering sampling pump is used for calculating and controlling the addition amount of the cleaning agent in the sample cell. The fluorescent color developing agent storage tank is connected with the sample cell through the third electromagnetic valve by a pipeline and is used for storing a fluorescent color developing agent. The third electromagnetic valve is connected with the sample cell and the fluorescent color developing agent storage tank by pipelines respectively and is used for controlling and adjusting the flow rate and pressure of the fluorescent color developing agent entering the sample cell. The metering sampling pump is connected with the sample cell by a pipeline and has different functions in different time periods. In a specific time, the metering sampling pump is used for calculating and controlling the addition amount of the fluorescent color developing agent in the sample cell.

[0010] The fluorescence detection module comprises a stabilized power supply, a xenon lamp, a first slit adjuster, a first wavelength adjuster, an excitation monochromator, a monitoring detector, a beam splitter, a light gate, a sample cell, an emission monochromator, a second slit adjuster, a second wavelength adjuster, a photomultiplier and an analog / digital converter; the stabilized power supply is connected with the xenon lamp through a wire to provide power support for the xenon lamp; the xenon lamp provides incident light for the whole system to excite the fluorescent color developer to generate fluorescence; the excitation monochromator is connected with the xenon lamp, and can convert the incident light provided by the xenon lamp into monochromatic light; the first slit adjuster and the first wavelength adjuster are connected with the excitation monochromator respectively to control the light intensity and wavelength of the monochromatic light formed by the excitation monochromator; the beam splitter is arranged between the light gate and the excitation monochromator to divide the monochromatic light into two beams, one of which leads to the sample cell, and the other of which leads to the monitoring detector; the monitoring detector is used for monitoring the change of the monochromatic light energy in real time; the light gate is arranged before the sample cell to turn off or turn on the monochromatic light entering the sample cell at any time; the emission monochromator is arranged after the sample cell to receive the fluorescent light emitted by the fluorescent color developer; the second slit adjuster and the second wavelength adjuster are connected with the emission monochromator respectively to control the light intensity and wavelength of the fluorescent light that can be received by the emission monochromator to the greatest extent; the photomultiplier is connected with the emission monochromator and the analog / digital converter to enhance the energy of the obtained fluorescent light for observation; the analog / digital converter is used for analog / digital signal conversion of the obtained signal, and then a digital photo or a fluorescence-concentration curve is formed.

[0011] The control module comprises a microprocessor, a display, a random memory and a remote workstation; the microprocessor is used for realizing logical processing and running state interaction among various modules in the device, and is also used for data interaction with the remote workstation; the random memory is used for storing various input / output function instruction sets, various analysis data and standard sample or to-be-measured microplastic fluorescence-concentration fitting curve equations; the display is used for displaying images and microplastic fluorescence-concentration fitting curves and the like; and the remote workstation is used for permanent storage of microplastic sampling data and establishment of a sampling database.

[0012] The application also discloses a detection method, which specifically comprises the following steps.

[0013] S1, the sampling connector is arranged in the water body, the metering sampling pump is started, and the fourth electromagnetic valve is started at the same time, at this time, the sampling water body is driven by the metering sampling pump to enter the device from the sampling connector, passes through the pipeline to enter the sample cell, the filter membrane is arranged in the sample cell, when the water sample passes through the filter membrane, the microplastic is filtered by the filter membrane and stays on the surface of the filter membrane, after the water sample passes through the filter membrane, the metering sampling pump continues to drive the water sample to flow out of the device, the microprocessor monitors the collection of the microplastic on the surface of the filter membrane in real time, and records the total volume V0 of the water body pumped by the metering sampling pump.

[0014] S2, close the fourth solenoid valve and open the first solenoid valve. Driven by the metering sampling pump, the digestant enters the sample cell from the digestant storage tank through the pipeline. After the sample cell is full, close the metering sampling pump, record the volume of digestant V1 extracted by the sampling pump, close the first solenoid valve, digest, and soak for at least 20 minutes to remove impurities other than microplastics from the filter membrane.

[0015] S3, turn on the metering sampling pump to discharge all the digester from the sample cell, open the second solenoid valve, and under the drive of the metering sampling pump, the cleaning agent enters the sample cell from the cleaning agent storage tank through the pipeline. After all the residual digester in the sample cell is cleaned, close the second solenoid valve and use the metering sampling pump to divert the cleaning agent out of the device. At the same time, open the third solenoid valve, and under the drive of the metering sampling pump, the fluorescent colorimetric agent enters the sample cell from the fluorescent colorimetric agent storage tank through the pipeline. After the fluorescent colorimetric agent is fully mixed with the microplastic and the staining of the microplastic is completed, close the third solenoid valve and record the volume V2 of the fluorescent colorimetric agent extracted by the sampling pump. Use the metering sampling pump again to divert the fluorescent colorimetric agent out of the device.

[0016] S4, the xenon lamp is turned on. The first slit modulator and the first wavelength modulator control the excitation monochromator to convert the incident light generated by the xenon lamp light source into monochromatic light suitable for exciting the fluorescent colorimetric agent. The monochromatic light is split into two beams by the beam splitter. One beam passes through the monitoring detector and is fed back to the microprocessor so that the microprocessor can fine-tune the first slit modulator and the first wavelength modulator. The other beam passes through the light shutter and enters the sample cell to excite the fluorescent colorimetric agent gathered on the surface of the microplastic on the filter membrane in the sample cell. The emission monochromator is responsible for collecting the generated excitation fluorescence. By adjusting the second slit modulator and the second wavelength modulator, the emission monochromator can receive all the excitation fluorescence generated by the microplastic and store the image in real time in the random access memory. The microprocessor can generate a microplastic fluorescence morphology image on the display by calling the input and output instructions in the memory, and can transmit the image to a remote workstation via the network.

[0017] S5. If quantitative detection of a certain microplastic continues, the second solenoid valve is opened, and the metering sampling pump is turned on. Driven by the metering sampling pump, the cleaning agent enters the sample cell from the cleaning agent storage tank through the pipeline to repeatedly clean the previously stained microplastic. After all the fluorescent agent on the surface of the microplastic is cleaned, the second solenoid valve is closed, and the metering sampling pump is used to divert the cleaning agent in the sample cell out of the device. At the same time, the third solenoid valve is opened, and driven by the metering sampling pump, a specific fluorescent colorimetric solution for the microplastic is selected and enters the sample cell from the fluorescent colorimetric solution storage tank through the pipeline. After the fluorescent colorimetric solution is fully mixed with the microplastic and the staining of the microplastic is completed, the metering sampling pump is turned off.

[0018] S6, the xenon lamp is turned on. Under the instruction of the microprocessor, the first slit modulator and the first wavelength modulator control the excitation monochromator to convert the incident light generated by the xenon lamp light source into monochromatic light suitable for the color development of the fluorescent reagent. The monochromatic light is split into two beams by the beam splitter. One beam passes through the monitoring detector and is fed back to the microprocessor so that the microprocessor can fine-tune the first slit modulator and the first wavelength modulator. The other beam passes through the light shutter and enters the sample cell to excite the fluorescent reagent on the surface of the microplastic in the sample cell. The emission monochromator is responsible for collecting the generated fluorescence. By adjusting the second slit modulator and the second wavelength modulator, the emission monochromator can receive all the generated fluorescence to the maximum extent. The light signal is amplified by the photomultiplier tube and transferred to the analog-to-digital converter. Finally, the maximum fluorescence curve of the microplastic can be generated on the display. After the microprocessor calls the fluorescence-concentration linear regression curve of the microplastic in the remote workstation, the concentration of the microplastic in the water can be calculated and the result is sent back to the remote workstation, thereby realizing the quantitative detection of a certain microplastic.

[0019] S7. If quantitative detection of other types of microplastics is required, S5 and S6 can be repeated.

[0020] Preferably, steps S1-S6 can perform quantitative and qualitative detection of microplastics, and all of them are completed based on fluorescence analysis methods.

[0021] Preferably, in the qualitative analysis pretreatment process, steps S1-S6 involve the sample being concentrated on the filter membrane in the sample cell, and digestion, staining, and other steps are also completed on the filter membrane.

[0022] Preferably, in steps S1-S6, the selection of specific fluorescent display agents allows the specific fluorescent display agents to combine with different microplastics during qualitative fluorescence detection, and after excitation, different colors of fluorescence are generated depending on the type of microplastic.

[0023] Preferably, the specific fluorescent display agents in steps S1-S6 are multiple, and the specific fluorescent display agents must not react with each other, and their simultaneous addition should not affect the final fluorescence detection result.

[0024] Preferably, pretreatment is still required before quantitative analysis in steps S1-S6. In order not to affect the quantitative results, the fluorescent agent on the surface of the microplastics needs to be washed off with a cleaning agent in the sample cell, and then a second staining is performed after washing.

[0025] Preferably, in steps S1-S6, when a certain microplastic component is selected for content determination, its concentration can be determined directly by calling the stored fluorescence-concentration curve data based on the photometric value, without the need to prepare a calibration solution.

[0026] Preferably, the fluorescence-concentration curves of all standards in steps S1-S6 must be measured and plotted in advance on the instrument and stored in random access memory and remote workstation respectively.

[0027] (III) Beneficial Effects

[0028] This invention provides a portable rapid detection method and device for microplastics based on fluorescence. Compared with the prior art, it has the following advantages:

[0029] (1) The portable rapid detection method and device for microplastics based on fluorescence comprises a sampling module, a pretreatment module, a fluorescence detection module, and a control module. The sampling module is connected to the pretreatment module and is used to collect microplastics in water. The pretreatment module is used to remove excess impurities, retain microplastics, and specifically stain them. The fluorescence detection module is connected to the pretreatment module and uses a xenon lamp light source to excite the sample stained by the pretreatment module, so that the stained sample produces fluorescence and quickly generates real-time images or fluorescence intensity-concentration curves. The control module is connected to the sampling module, the pretreatment module, and the fluorescence detection module respectively and is used for the operation control of the sampling module, the pretreatment module, and the fluorescence detection module as well as external communication. This portable rapid detection device for microplastics has a high degree of automation and can quickly and accurately complete the qualitative and quantitative analysis of microplastics on-site, avoiding the time and cost of sending samples back to the laboratory for analysis. It saves time and effort, effectively improves the efficiency of microplastic detection of samples, and greatly reduces the cost of microplastic detection of samples.

[0030] (2) The portable rapid detection method and device for microplastics based on fluorescence includes a control module comprising a microprocessor, a display, a random access memory (RAM), and a remote workstation. The microprocessor is used to realize the logical processing and interaction of various modules within the device, and is also used for data interaction with the remote workstation. The RAM is used to store various input / output function instruction sets, as well as various analytical data and fluorescence intensity-concentration fitting curve equations of standard samples or microplastics to be tested. The display is used to display images and fluorescence intensity-concentration fitting curves of microplastics. The remote workstation is used for permanent storage of microplastic sampling data and establishment of a sampling database. Through the setting of the RAM and the remote workstation, it is convenient to perform real-time qualitative and quantitative analysis and remote monitoring of microplastics in water. Attached Figure Description

[0031] Fig. 1 This is a schematic diagram of the component connections of the present invention;

[0032] Fig. 2 This is a process flow diagram of the present invention.

[0033] In the diagram, 1 is a remote workstation, 2 is a filter membrane, 3 is a microprocessor, 4 is a display, 5 is a regulated power supply, 6 is a xenon lamp, 7 is an excitation monochromator, 8 is a monitoring detector, 9 is a random access memory, 10 is an analog-to-digital converter, 11 is a photomultiplier tube, 12 is an emission monochromator, 13 is a beam splitter, 14 is a shutter, 15 is a first slit modulator, 16 is a first wavelength modulator, 17 is a second slit modulator, 18 is a second wavelength modulator, 19 is a sample cell, 20 is a digester tank, 21 is a metering sampling pump, 22 is a fluorescent colorimetric reagent tank, 23 is a cleaning agent tank, 24 is a sampling connector, 25 is a first solenoid valve, 26 is a second solenoid valve, 27 is a third solenoid valve, and 28 is a fourth solenoid valve. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Please see Figs. 1-2 This invention provides a technical solution: a portable microplastic rapid detection device based on fluorescence, comprising a sampling module, a preprocessing module, a fluorescence detection module, and a control module; the sampling module is connected to the preprocessing module and is used to collect microplastics in water; the preprocessing module is used to remove excess impurities, retain microplastics, and specifically stain them; the fluorescence detection module is connected to the preprocessing module and uses a xenon lamp light source to excite the sample stained by the preprocessing module, causing the stained sample to fluoresce and rapidly generate a real-world image or a fluorescence intensity-concentration curve; the control module is connected to the sampling module, the preprocessing module, and the fluorescence detection module respectively, and is used for the operation control of the sampling module, the preprocessing module, and the fluorescence detection module, as well as external communication.

[0036] The sampling module includes a metering sampling pump 21, a sample cell 19, a fourth solenoid valve 28, and a sampling connector 24. The sampling connector 24 is connected to the water body on site for water sample collection. The fourth solenoid valve 28 is connected to the sample cell 19 and the sampling connector 24 through pipelines to control and adjust the flow rate and pressure of the water sample entering the sample cell 19. The sample cell 19 is used for sample collection and is lined with a filter membrane 2 made of acid-resistant plastic, which can filter microplastics in the water. The metering sampling pump 21 is connected to the sample cell 19 through pipelines. The metering sampling pump 21 has different functions at different times, and is used to calculate and control the water volume in the sample cell 19 at a specific time.

[0037] The pretreatment module includes a metering sampling pump 21, a sample cell 19, a digester storage tank 20, a first solenoid valve 25, a cleaning agent storage tank 23, a second solenoid valve 26, a fluorescent colorimetric reagent storage tank 22, and a third solenoid valve 27. The digester storage tank 20 is connected to the sample cell 19 via the first solenoid valve 25 and a pipeline, and is used to store acidic digester. The first solenoid valve 25 is connected to both the sample cell 19 and the digester storage tank 20 via pipelines, and is used to control and regulate the flow rate and pressure of the digester entering the sample cell 19. The metering sampling pump 21 is connected to the sample cell 19 via a pipeline. The metering sampling pump 21 has different functions at different times, and is used to calculate and control the amount of digester added to the sample cell 19 within a specific time period. The cleaning agent storage tank 23 is connected to the sample cell 19 via the second solenoid valve 26 and a pipeline, and is used to store cleaning agent. The second solenoid valve 26 is connected to both the sample cell 19 and the sample cell 19 via the second solenoid valve 26 and a pipeline, and is used to store cleaning agent. The sample cell 19 and the cleaning agent storage tank 23 are connected by pipelines to control and regulate the flow rate and pressure of the digester entering the sample cell 19. The metering sampling pump 21 is connected to the sample cell 19 by pipelines. The metering sampling pump 21 has different functions at different times, and is used to calculate and control the amount of cleaning agent added to the sample cell 19 at a specific time. The fluorescent colorimetric agent storage tank 22 is connected to the sample cell 19 by pipelines through the third solenoid valve 27 and is used to store the fluorescent colorimetric agent. The third solenoid valve 27 is connected to both the sample cell 19 and the fluorescent colorimetric agent storage tank 22 by pipelines to control and regulate the flow rate and pressure of the fluorescent colorimetric agent entering the sample cell 19. The metering sampling pump 21 is connected to the sample cell 19 by pipelines. The metering sampling pump 21 has different functions at different times, and is used to calculate and control the amount of fluorescent colorimetric agent added to the sample cell 19 at a specific time.

[0038] The fluorescence detection module includes a regulated power supply 5, a xenon lamp 6, a first slit modulator 15, a first wavelength modulator 16, an excitation monochromator 7, a monitoring detector 8, a beam splitter 13, a shutter 14, a sample cell 19, an emission monochromator 12, a second slit modulator 17, a second wavelength modulator 18, a photomultiplier tube 11, and an analog-to-digital converter 10. The regulated power supply 5 is connected to the xenon lamp 6 via wires to provide power. The xenon lamp 6 provides incident light to the entire system to excite the fluorescent reagent to fluoresce. The excitation monochromator 7 is connected to the xenon lamp 6 and converts the incident light provided by the xenon lamp light source into monochromatic light. The first slit modulator 15 and the first wavelength modulator 16 are respectively connected to the excitation monochromator 7 to control the intensity and wavelength of the monochromatic light formed by the excitation monochromator 7. The beam splitter 13 is placed between the shutter 14 and the excitation monochromator 7. The device is used to split monochromatic light into two beams, one of which leads to the sample cell 19 and the other to the monitoring detector 8. The monitoring detector 8 is used to monitor the changes in monochromatic light energy in real time. The shutter 14 is placed in front of the sample cell 19 to turn the monochromatic light entering the sample cell 19 on or off at any time. The emission monochromator 12 is placed after the sample cell 19 to receive the fluorescent light emitted by the fluorescent developer. The second slit modulator 17 and the second wavelength modulator 18 are respectively connected to the emission monochromator 12 to control the intensity and wavelength of the fluorescent light received by the emission monochromator 12 to the maximum extent. The photomultiplier tube 11 is connected to the emission monochromator 12 and the analog-to-digital converter 10 to enhance the energy of the obtained fluorescent light for easy observation. The analog-to-digital converter 10 is used to convert the obtained signal into an analog signal to a digital signal, thereby forming a digital photograph or a fluorescence intensity-concentration curve.

[0039] The control module includes a microprocessor 3, a display 4, a random access memory 9, and a remote workstation 1. The microprocessor 3 is used to realize the logical processing and interaction of various modules within the device, and is also used for data interaction with the remote workstation 1. The random access memory 9 is used to store various input / output function instruction sets, as well as various analytical data and fluorescence-concentration fitting curve equations of standard samples or microplastics to be tested. The display 4 is used to display images and fluorescence-concentration fitting curves of microplastics, etc. The remote workstation 1 is used for permanent storage of microplastic sampling data and the establishment of a sampling database.

[0040] This invention also discloses a detection method, which specifically includes the following steps:

[0041] S1, place the sampling connector 24 in the water body, turn on the metering sampling pump 21, and simultaneously turn on the fourth solenoid valve 28. At this time, the water body is driven by the metering sampling pump 21, enters the device from the sampling connector 24, and enters the sample pool 19 through the pipeline. The sample pool has a built-in filter membrane 2. When the water sample passes through the filter membrane 2, the microplastics are filtered by the filter membrane 2 and remain on the surface of the filter membrane 2. After the water sample passes through the filter membrane 2, it continues to be driven by the metering sampling pump 21 and flows out of the device from the metering sampling pump 21. The microprocessor monitors the collection of microplastics on the surface of the filter membrane 2 in real time and records the total volume V0 of the water body extracted by the metering sampling pump 21.

[0042] S2, close the fourth solenoid valve 28, open the first solenoid valve 25, and under the drive of the metering sampling pump 21, the digestant enters the sample cell 19 from the digestant storage tank 20 through the pipeline. After the sample cell 19 is filled, close the metering sampling pump 21, record the volume V1 of digestant extracted by the sampling pump 21, close the first solenoid valve 25, and digest and soak for at least 20 minutes to remove other impurities on the filter membrane 2 except for microplastics.

[0043] S3, turn on the metering sampling pump 21 to discharge all the digesting agent from the sample cell 19, turn on the second solenoid valve 26, and under the drive of the metering sampling pump 21, the cleaning agent enters the sample cell 19 from the cleaning agent storage tank 23 through the pipeline. After the remaining digesting agent in the sample cell 19 is completely cleaned, turn off the second solenoid valve 26 and use the metering sampling pump 21 to divert the cleaning agent out of the device. At the same time, turn on the third solenoid valve 27, and under the drive of the metering sampling pump 21, the fluorescent colorimetric agent enters the sample cell 19 from the fluorescent colorimetric agent storage tank 22 through the pipeline. After the fluorescent colorimetric agent is fully mixed with the microplastic and the staining of the microplastic is completed, turn off the third solenoid valve 27, record the volume V2 of the fluorescent colorimetric agent extracted by the sampling pump 21, and use the metering sampling pump 21 again to divert the fluorescent colorimetric agent out of the device.

[0044] S4, the xenon lamp 6 is turned on. The first slit modulator 15 and the first wavelength modulator 16 control the excitation monochromator 7 to convert the incident light generated by the xenon lamp light source into monochromatic light suitable for exciting the fluorescent colorimetric agent. The monochromatic light is split into two beams by the beam splitter 13. One beam passes through the monitoring detector 8 and is fed back to the microprocessor so that the microprocessor can fine-tune the first slit modulator 15 and the first wavelength modulator 16. The other beam passes through the light shutter 14 and enters the sample cell 19 to excite the fluorescent colorimetric agent gathered on the surface of the microplastic on the filter membrane in the sample cell. The emission monochromator 12 is responsible for collecting the generated excitation fluorescence. By adjusting the second slit modulator 17 and the second wavelength modulator 18, the emission monochromator 12 can receive all the excitation fluorescence generated by the microplastic and store the image in real time in the random access memory. The microprocessor can generate a microplastic fluorescence morphology image on the display 4 by calling the input and output instructions in the memory, and can transmit the image to the remote workstation 1 via the network.

[0045] S5. If quantitative detection of a certain microplastic continues, the second solenoid valve 26 is opened, and the metering sampling pump 21 is turned on. Driven by the metering sampling pump 21, the cleaning agent enters the sample cell 19 from the cleaning agent storage tank 23 through the pipeline to repeatedly clean the previously stained microplastic. After all the fluorescent agent on the surface of the microplastic is cleaned, the second solenoid valve 26 is closed, and the cleaning agent in the sample cell is diverted out of the device by the metering sampling pump 21. At the same time, the third solenoid valve 27 is opened. Driven by the metering sampling pump 21, a specific fluorescent colorimetric solution for the microplastic is selected and enters the sample cell 19 from the fluorescent colorimetric solution storage tank 22 through the pipeline. After the fluorescent colorimetric solution is fully mixed with the microplastic and the staining of the microplastic is completed, the metering sampling pump 21 is turned off.

[0046] S6, the xenon lamp 6 is turned on. Under the instruction of the microprocessor 3, the first slit adjuster 15 and the first wavelength adjuster 16 control the excitation monochromator 7 to convert the incident light generated by the xenon lamp source into monochromatic light suitable for the color development of the fluorescent reagent. The monochromatic light is split into two beams by the beam splitter 13. One beam passes through the monitoring detector 8 and is fed back to the microprocessor so that the microprocessor can fine-tune the first slit adjuster 15 and the first wavelength adjuster 16. The other beam passes through the light shutter 14 and enters the sample cell 19 to excite the fluorescent reagent on the surface of the microplastic in the sample cell and emit light. Monochromator 12 is responsible for collecting the generated fluorescence. By adjusting the second slit modulator 17 and the second wavelength modulator 18, the emission monochromator 12 can receive all the generated fluorescence to the maximum extent. The light signal is amplified by photomultiplier tube 11 and transferred to analog-to-digital converter 10. Finally, the maximum fluorescence curve of the microplastic can be generated on display 4. After the microprocessor calls the fluorescence-concentration linear regression curve of the microplastic in the remote workstation 1, the concentration of the microplastic in the water can be calculated and the result is sent back to the remote workstation, thereby realizing the quantitative detection of a certain microplastic.

[0047] S7. If quantitative detection of other types of microplastics is required, S5 and S6 can be repeated.

[0048] In this embodiment of the invention, steps S1-S6 can perform quantitative and qualitative detection of microplastics, and all of them are completed based on fluorescence analysis methods.

[0049] In this embodiment of the invention, during the qualitative analysis pretreatment process in steps S1-S4, the sample is concentrated on the filter membrane in the sample cell, and digestion, staining and other steps are also completed on the filter membrane.

[0050] In this embodiment of the invention, the selection of specific fluorescent display agents in steps S1-S6 allows for the combination of specific fluorescent display agents with different microplastics during qualitative fluorescence detection, and the generation of different colors of fluorescence after excitation, depending on the type of microplastic.

[0051] In this embodiment of the invention, the specific fluorescent display agents in steps S1-S6 are of multiple types, and the specific fluorescent display agents must not react with each other, and their simultaneous addition should not affect the final fluorescence detection result.

[0052] In this embodiment of the invention, pretreatment is still required before quantitative analysis in steps S1-S6. In order not to affect the quantitative results, the fluorescent agent on the surface of the microplastics needs to be washed off with a cleaning agent in the sample cell, and then a second staining is performed after washing.

[0053] In this embodiment of the invention, when a certain microplastic component is selected for content determination in steps S1-S6, its concentration can be determined by directly calling the stored fluorescence-concentration curve data based on the photometric value, without the need to prepare a calibration solution.

[0054] In this embodiment of the invention, the fluorescence-concentration curves of all standards in steps S1-S6 must be measured and plotted in advance on the instrument and stored in the random access memory and remote workstation respectively.

[0055] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0056] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A portable rapid detection device for microplastics based on fluorescence, characterized in that: It includes a sampling module, a preprocessing module, a fluorescence detection module, and a control module. The sampling module is connected to the preprocessing module and is used to collect microplastics in water. The preprocessing module is used to remove excess impurities, retain microplastics, and specifically stain them. The fluorescence detection module is connected to the preprocessing module and uses a xenon lamp light source to excite the sample stained by the preprocessing module, causing the stained sample to fluoresce and quickly generate a real-world image or a fluorescence intensity-concentration curve. The control module is connected to the sampling module, the preprocessing module, and the fluorescence detection module respectively, and is used for the operation control of the sampling module, the preprocessing module, and the fluorescence detection module, as well as external communication. The sampling module includes a metering sampling pump (21), a sample pool (19), a fourth solenoid valve (28), and a sampling connector (24). The sampling connector (24) is connected to the water body on site for collecting water samples. The fourth solenoid valve (28) is connected to the sample pool (19) and the sampling connector (24) through pipelines to control and adjust the flow rate and pressure of the water sample entering the sample pool (19). The sample pool (19) is used for sample collection. The sample pool (19) is lined with a filter membrane (2). The filter membrane (2) is made of acid-resistant plastic and can filter microplastics in the water. The metering sampling pump (21) is connected to the sample pool (19) through pipelines. The metering sampling pump (21) has different functions at different times. At a specific time, it is used to calculate and control the amount of water in the sample pool (19). The pretreatment module includes a metering sampling pump (21), a sample cell (19), a digester storage tank (20), a first solenoid valve (25), a cleaning agent storage tank (23), a second solenoid valve (26), a fluorescent colorimetric agent storage tank (22), and a third solenoid valve (27). The digester storage tank (20) is connected to the sample cell (19) via a pipeline through the first solenoid valve (25) and is used to store acidic digester. The first solenoid valve (25) is connected to both the sample cell (19) and the digester storage tank (20). The sample pool (19) is connected by a pipeline to control and regulate the flow rate and pressure of the digester entering the sample pool (19); the metering sampling pump (21) is connected to the sample pool (19) by a pipeline, and the metering sampling pump (21) has different functions at different times, and is used to calculate and control the amount of digester added to the sample pool (19) at a specific time; the cleaning agent storage tank (23) is connected to the sample pool (19) by a pipeline through a second solenoid valve (26) and is used to store the cleaning agent; the second solenoid valve (26) is connected to both the sample pool (19) and the cleaning agent storage tank (23). The sample cell (19) is connected to the sample cell (19) via a pipeline. The metering sampling pump (21) is connected to the sample cell (19) via a pipeline. The metering sampling pump (21) has different functions at different times. At a specific time, it is used to calculate and control the amount of cleaning agent added to the sample cell (19). The fluorescent colorimetric agent storage tank (22) is connected to the sample cell (19) via a pipeline through a third solenoid valve (27). It is used to store the fluorescent colorimetric agent. The third solenoid valve (27) is connected to the sample cell (19) and the fluorescent colorimetric agent storage tank (22) via pipelines. It is used to control and adjust the flow rate and pressure of the fluorescent colorimetric agent entering the sample cell (19). The metering sampling pump (21) is connected to the sample cell (19) via a pipeline. The metering sampling pump (21) has different functions at different times. At a specific time, it is used to calculate and control the amount of fluorescent colorimetric agent added to the sample cell (19). The fluorescence detection module includes a regulated power supply (5), a xenon lamp (6), a first slit modulator (15), a first wavelength modulator (16), an excitation monochromator (7), a monitoring detector (8), a beam splitter (13), a shutter (14), a sample cell (19), an emission monochromator (12), a second slit modulator (17), a second wavelength modulator (18), a photomultiplier tube (11), and an analog-to-digital converter (10). The regulated power supply (5) is connected to the xenon lamp (6) via a wire to provide power to the xenon lamp (6). The xenon lamp (6) provides incident light to the entire system to excite the fluorescent chromogenic agent to fluoresce. The excitation monochromator (7) is connected to the xenon lamp (6) and can convert the incident light provided by the xenon lamp light source into monochromatic light; the first slit modulator (15) and the first wavelength modulator (16) are respectively connected to the excitation monochromator (7) to control the light intensity and wavelength of the monochromatic light formed by the excitation monochromator (7); the beam splitter (13) is placed between the light shutter (14) and the excitation monochromator (7) to split the monochromatic light into two beams, one of which leads to the sample cell (19) and the other to the monitoring detector (8); the monitoring detector (8) is used to monitor the change of monochromatic light energy in real time; the light shutter (14) is placed in front of the sample cell (19) to close or open the monochromatic light entering the sample cell (19) at any time; the emission monochromator (12) is placed after the sample cell (19) to receive the fluorescent light emitted by the fluorescent developer; the second slit modulator (17) and the second wavelength modulator (18) The photomultiplier tube (11) is connected to the emission monochromator (12) to control the emission monochromator (12) to receive the fluorescence light intensity and wavelength to the maximum extent; the photomultiplier tube (11) is connected to the emission monochromator (12) and the analog-to-digital converter (10) to enhance the energy of the obtained fluorescence light for easy observation; the analog-to-digital converter (10) is used to convert the obtained signal into an analog-to-digital signal, and then form a digital photograph or fluorescence intensity-concentration curve; The control module includes a microprocessor (3), a display (4), a random access memory (9), and a remote workstation (1). The microprocessor (3) is used to realize the logical processing and operation status interaction between various modules inside the device. The microprocessor (3) is also used for data interaction with the remote workstation (1). The random access memory (9) is used to store various input / output function instruction sets, as well as various analytical data and fluorescence-concentration fitting curve equations of standard samples or microplastics to be tested. The display (4) is used to display images and fluorescence-concentration fitting curves of microplastics. The remote workstation (1) is used for permanent storage of microplastic sampling data and the establishment of a sampling database.

2. The detection method using the portable microplastic rapid detection device based on fluorescence as described in claim 1, characterized in that: Specifically, the following steps are included: S1, place the sampling connector (24) in the water body, turn on the metering sampling pump (21), and simultaneously turn on the fourth solenoid valve (28). At this time, the sampled water body is driven by the metering sampling pump (21) and enters the device from the sampling connector (24), and enters the sample pool (19) through the pipeline. The sample pool has a built-in filter membrane (2). When the water sample passes through the filter membrane (2), the microplastics are filtered by the filter membrane (2) and remain on the surface of the filter membrane (2). After the water sample passes through the filter membrane (2), it continues to be driven by the metering sampling pump (21) and flows out of the device from the metering sampling pump (21). The microprocessor monitors the collection of microplastics on the surface of the filter membrane (2) in real time and records the total volume V0 of the water body extracted by the metering sampling pump (21). S2, close the fourth solenoid valve (28), open the first solenoid valve (25), and under the drive of the metering sampling pump (21), the digestant enters the sample cell (19) from the digestant storage tank (20) through the pipeline. After the sample cell (19) is filled, close the metering sampling pump (21), record the volume V1 of the digestant extracted by the metering sampling pump (21), close the first solenoid valve (25), digest, and soak for at least 20 minutes to remove other impurities on the filter membrane (2) except for microplastics. S3, turn on the metering sampling pump (21) to discharge all the digesting agent from the sample cell (19), turn on the second solenoid valve (26), and under the drive of the metering sampling pump (21), the cleaning agent enters the sample cell (19) from the cleaning agent storage tank (23) through the pipeline. After the residual digesting agent in the sample cell (19) is completely cleaned, turn off the second solenoid valve (26) and use the metering sampling pump (21) to divert the cleaning agent out of the device. At the same time, turn on the third solenoid valve (27), and under the drive of the metering sampling pump (21), the fluorescent colorimetric agent enters the sample cell (19) from the fluorescent colorimetric agent storage tank (22) through the pipeline. After the fluorescent colorimetric agent and microplastic are fully mixed and the microplastic is dyed, turn off the third solenoid valve (27), record the volume V2 of the fluorescent colorimetric agent extracted by the metering sampling pump (21), and use the metering sampling pump (21) again to divert the fluorescent colorimetric agent out of the device. S4, turn on the xenon lamp (6), and control the excitation monochromator (7) through the first slit modulator (15) and the first wavelength modulator (16) to convert the incident light generated by the xenon lamp light source into monochromatic light suitable for exciting the fluorescent colorimetric reagent. The monochromatic light is split into two beams through the beam splitter (13). One beam passes through the monitoring detector (8) and is fed back to the microprocessor so that the microprocessor can fine-tune the first slit modulator (15) and the first wavelength modulator (16). The other beam passes through the light shutter (14) and enters the sample cell (19) to excite the fluorescent colorimetric reagent gathered on the microplastic surface of the filter membrane in the sample cell. The emission monochromator (12) is responsible for collecting the generated excitation fluorescence. The emission monochromator (12) can be adjusted by adjusting the second slit modulator (17) and the second wavelength modulator (18). It can receive all the excitation fluorescence generated by microplastics and store the image in random access memory in real time. The microprocessor can generate a microplastic fluorescence morphology image on the display (4) by calling the input and output instructions in the memory, and can transmit the image to a remote workstation (1) via the network. S5. If quantitative detection of a certain microplastic is to be continued, the second solenoid valve (26) is opened and the metering sampling pump (21) is turned on. Under the drive of the metering sampling pump (21), the cleaning agent enters the sample cell (19) from the cleaning agent storage tank (23) through the pipeline to repeatedly clean the microplastic that has been stained. After all the fluorescent agent on the surface of the microplastic is cleaned, the second solenoid valve (26) is closed and the cleaning agent in the sample cell is diverted out of the device by the metering sampling pump (21). At the same time, the third solenoid valve (27) is opened. Under the drive of the metering sampling pump (21), a specific fluorescent colorimetric solution for the microplastic is selected and enters the sample cell (19) from the fluorescent colorimetric solution storage tank (22) through the pipeline. After the fluorescent colorimetric solution is fully mixed with the microplastic and the staining of the microplastic is completed, the metering sampling pump (21) is turned off. S6, turn on the xenon lamp (6). Under the instruction of the microprocessor (3), the excitation monochromator (7) is controlled by the first slit modulator (15) and the first wavelength modulator (16) to convert the incident light generated by the xenon lamp light source into monochromatic light suitable for the color development of the fluorescent colorimetric agent. The monochromatic light is split into two beams by the beam splitter (13). One beam passes through the monitoring detector (8) and is fed back to the microprocessor so that the microprocessor can fine-tune the first slit modulator (15) and the first wavelength modulator (16). The other beam passes through the light shutter (14) and enters the sample cell (19) to excite the fluorescent agent on the surface of the microplastic in the sample cell. The emission monochromator (12) is responsible for collecting the generated fluorescence. The emission monochromator (12) can be adjusted by adjusting the second slit modulator (17) and the second wavelength modulator (18). The system receives all the generated fluorescence to the maximum extent and amplifies the light signal through a photomultiplier tube (11) before transferring it to an analog-to-digital converter (10). Finally, the maximum fluorescence curve of the microplastic can be generated on the display (4). After the microprocessor calls the fluorescence-concentration linear regression curve of the microplastic in the remote workstation (1), the concentration of the microplastic in the water can be calculated and the result can be sent back to the remote workstation, thereby realizing the quantitative detection of a certain microplastic. S7. If quantitative detection of other types of microplastics is required, repeat S5 and S6.

3. The detection method according to claim 2, characterized in that: Steps S1-S6 can perform quantitative and qualitative detection of microplastics, and all of them are based on fluorescence analysis methods.

4. The detection method according to claim 2, characterized in that: In the qualitative analysis pretreatment process, steps S1-S4 involve the sample being concentrated on the filter membrane (2) in the sample cell, and the digestion and staining steps are also completed on the filter membrane (2).

5. The detection method according to claim 2, characterized in that: In steps S1-S6, the selection of specific fluorescent display agents allows for the combination of specific fluorescent display agents with different microplastics during qualitative fluorescence detection. After excitation, different colors of fluorescence are produced depending on the type of microplastic.

6. The detection method according to claim 5, characterized in that: In steps S1-S6, there are multiple specific fluorescent display agents. These specific fluorescent display agents must not react with each other, and their simultaneous addition should not affect the final fluorescence detection result.

7. The detection method according to claim 2, characterized in that: Before quantitative analysis in steps S1-S6, pretreatment is still required. In order not to affect the quantitative results, the fluorescent agent on the surface of the microplastics needs to be washed off with a cleaning agent in the sample cell, and then a second staining is performed.

8. The detection method according to claim 2, characterized in that: In steps S1-S6, when a certain microplastic component is selected for content determination, its concentration can be determined directly by calling the stored fluorescence-concentration curve data based on the photometric value, without the need to prepare a calibration solution.

9. The detection method according to claim 8, characterized in that: In steps S1-S6, the fluorescence-concentration curves of all standards must be measured and plotted in advance on the instrument and stored in random access memory and remote workstation, respectively.

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