High-flux enrichment and rapid detection device for microplastic pollution in water body

Abstract

The invention discloses a high-flux enrichment and rapid detection device for micro-plastic pollution in a water body. The device comprises a sample pretreatment unit, a multi-mode detection unit, a specific marking unit and a unified and coordinated intelligent control unit, the sample pretreatment unit realizes continuous online digestion and lossless concentration of a water sample through a micro-fluidic chip and a field control enrichment technology; the multi-mode detection unit synchronously triggers the high-resolution microscopic imaging and Raman spectrum assembly to synchronously collect the form and chemical components of a single particle; the specific labeling unit realizes selective labeling and signal enhancement of nano-scale plastic particles through a specific probe; through microfluidic automation and multi-modal data fusion technologies, the industrial problems of tedious pretreatment, low nano-plastic capture rate and high complex matrix misjudgment rate in a traditional method are effectively solved, and the method has the comprehensive advantages of high throughput, full automation and accurate diagnosis.

Description

Technical Field

[0001] This invention relates to the field of environmental monitoring technology, and in particular to an analytical device for microplastic pollution in water bodies, specifically a high-throughput rapid detection device and method based on the combination of microfluidic enrichment and multimodal optical detection. Background Technology

[0002] Microplastics, as an emerging persistent pollutant, have been widely detected in marine and inland waters and even drinking water sources. Their environmental migration, ecotoxicology, and human health risks have become a global environmental focus. The accurate identification and quantitative analysis of microplastics, especially nanoscale plastic particles, is a scientific prerequisite for objectively assessing their environmental behavior and ecological effects, and is also the core basis for formulating relevant environmental standards and governance strategies. However, microplastics in environmental media are characterized by a large size range, diverse chemical compositions, complex morphological features, and strong background matrix interference. This places extremely stringent requirements on the capture efficiency, identification accuracy, and throughput of analytical techniques, and is a major technical bottleneck currently facing the field of environmental analytical chemistry. Currently, the mainstream microplastic detection technologies in the industry mainly rely on two categories: simple physical sieving / density flotation and single spectroscopic identification technology. Both of these core processes have significant limitations. Simple physical enrichment methods achieve pre-concentration through membrane filtration or density separation. Although they can process large amounts of water samples, they are prone to the loss of nanoscale particles, the entanglement and retention of fibrous particles, and the co-enrichment of complex natural particles, causing serious interference to subsequent analyses. Single spectroscopic identification technologies, such as micro-infrared or Raman spectroscopy, can provide chemical composition information, but they usually rely on manual operation and visual target finding, which is inefficient and difficult to effectively detect submicron particles. Furthermore, they cannot simultaneously obtain the morphological parameters of individual particles to assist in the judgment. In sample processing and analysis, existing technologies generally follow a discrete operation mode of offline enrichment, offline transfer, and instrumental analysis, meaning that water sample collection, pretreatment, and instrument detection are completely separated in time and space. Under this approach, samples face a high risk of loss and contamination during multiple transfers, and the numerous manual operation steps introduce significant uncertainty, resulting in poor reproducibility and long analysis cycles. For example, when enriching samples through membrane filtration before microscopic observation, the filter membrane itself may introduce plastic background interference, and the random spatial distribution of particles makes it difficult to achieve high-throughput automatic positioning. If the enriched sample is resuspended and transferred to the spectral sample cell, particle aggregation and loss of target substances are inevitable. At the same time, existing technologies generally lack the ability to specifically capture and enhance signals of nanoscale plastics, and morphological and chemical analyses are disconnected, leading to a dual dilemma when dealing with samples from complex environments: insufficient sensitivity for detecting small-sized particles and a high false positive rate for non-plastic particles. With the deepening implementation of the "Water Ten Measures" environmental protection policy and the increasing public concern for drinking water safety, the need for monitoring microplastics, especially submicron and nano-sized plastics, in environmental water bodies is shifting from scientific research to routine regulation. This scenario requires detection technologies to possess high throughput, high sensitivity, high automation, and strong anti-interference capabilities to handle complex real-world water samples. However, existing detection technologies suffer from two major shortcomings: First, the discrete offline operation mode leads to lengthy analysis processes, significant human error, and difficulty in achieving rapid in-situ response, failing to meet the efficiency and consistency requirements of large-scale environmental screening. Second, the limitations of single technical methods result in high detection limits, incomplete size coverage, and a single chain of evidence for identification. Even with extended analysis times or combinations of multiple technologies, it remains difficult to achieve accurate and rapid statistical analysis and identification of plastic particles across the entire micron to nanoscale in complex matrices, failing to meet the urgent need for comprehensive and accurate diagnosis of microplastic pollution in the new era. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-throughput enrichment and rapid detection device for microplastic pollution in water bodies, which can achieve high-throughput enrichment and rapid detection of microplastics in water bodies.

[0004] The objective of this invention can be achieved through the following technical solutions: This application provides a high-throughput enrichment and rapid detection device for microplastic pollution in water bodies, characterized by comprising a sample pretreatment unit, a specific labeling unit, and a multimodal detection unit, as well as an intelligent control unit for unified regulation of each unit; Furthermore, the sample pretreatment unit includes a microfluidic chip and a field-controlled enrichment device; the microfluidic chip is provided with a sample inlet and a waste liquid outlet, used for introducing the water sample to be tested and discharging the waste liquid after fractionation and enrichment, respectively; the microfluidic chip adopts a multi-layer microchannel structure, including a main channel and two secondary channels; the starting end of the main channel is the sample inlet, and it runs through the sample pretreatment unit, the specific labeling unit, and the multimodal detection unit; the two secondary channels have waste liquid outlets at the ends of the channels, and are symmetrically distributed on both sides of the main channel, communicating with the main channel through microscale pores; the field-controlled enrichment device is disposed outside the tube wall of the microfluidic chip, and is used for non-destructive concentration and fractionation of microplastic particles in the water sample in the sample inlet section; Preferably, the specific labeling unit is located on the right side of the sample pretreatment unit, including a labeling reaction chamber and a probe injection device; the labeling reaction chamber is coaxially sleeved outside the wall of the microfluidic chip; the outlet end of the probe injection device is connected to the main channel of the microfluidic chip through a feeding pipe, and is used to inject specific Raman reporter probes into the microplastic particles after non-destructive concentration and classification; the field-controlled enrichment device adopts a composite enrichment structure of dielectrophoretic enrichment electrode and acoustic field enrichment transducer; wherein, the dielectrophoretic enrichment electrode is located on the axial inner side of the field-controlled enrichment device, including at least three pairs of mutually parallel electrode plates, and generates dielectrophoretic force through the non-uniform electric field formed between adjacent electrode plates, which is used for primary enrichment of passing microplastic particles; Preferably, the sound field enrichment transducer is disposed on the axial outer side of the specific marking unit, and includes a ring piezoelectric ceramic and a sound field focuser; the ring piezoelectric ceramic and the sound field focuser are arranged concentrically from the outside to the inside, and a sound field node is formed by exciting a sound field of a specific frequency under the action of the sound field focuser, so as to perform secondary enrichment for nanoscale plastic particles. Preferably, the multimodal detection unit is disposed to the right of the specific labeling unit, and includes a detection chamber, a microscopic imaging component, and a Raman spectroscopy component; the detection chamber is coaxially sleeved on the outside of the wall of the microfluidic chip; the microscopic imaging component is vertically disposed above the detection chamber; the Raman spectroscopy component is disposed radially to the right of the detection chamber, for simultaneously acquiring morphological images and chemical composition spectra of particles flowing through the interior of the detection chamber. Preferably, the intelligent control unit is independently configured, including a central processing unit and a sensor group; the sensor group has three sets of sensors, which are respectively located inside the field-controlled enrichment device, the labeling reaction chamber, and the detection chamber; the central processing unit is electrically connected to the field-controlled enrichment device, the probe injection device, the microscopic imaging component, the Raman spectroscopy component, and the sensor group via control cables, forming a centralized control and collaborative regulation device for real-time collaborative adjustment of enrichment field strength, probe injection parameters, and optical detection parameters based on sensor data.

[0005] Beneficial effects:

[0006] This invention solves the technical problems of low enrichment efficiency, long detection cycle, and difficulty in achieving high-throughput simultaneous analysis in the detection of microplastics in water bodies by integrating high-throughput enrichment and rapid detection through a collaborative design. It utilizes an integrated device consisting of a sample pretreatment unit, a multimodal detection unit, a specific labeling unit, and a unified and coordinated intelligent control unit to achieve the coordinated rapid enrichment and accurate detection of microplastics in water bodies.

[0007] Specifically, a high-throughput separation and enrichment environment for microplastics in water was established through gradient filtration and targeted adsorption technology of the high-efficiency enrichment unit, providing a high-purity sample basis for subsequent rapid detection. The morphological characteristics and chemical composition of the enriched microplastics were simultaneously identified through the coordinated optical path of microscopic imaging and Raman spectroscopy in the orthogonal confocal detection unit. Real-time coordinated adaptation of enrichment flow rate, detection sensitivity, and signal acquisition was achieved through the sensing feedback and parameter control device of the intelligent control unit. The precise sample delivery structure of the linkage transmission unit ensured lossless and continuous transmission of the enriched sample to the detection module.

[0008] This invention effectively solves the problems of disconnect between enrichment and detection, cumbersome operation, and insufficient throughput in traditional detection methods by using a high-throughput enrichment and rapid detection device for microplastic pollution in water bodies. It forms a virtuous closed loop integrating enrichment, transmission, and detection. Compared with existing technologies, this invention significantly improves the detection efficiency and accuracy of microplastics in water bodies, while achieving a comprehensive effect of high-throughput enrichment, rapid detection, and integrated operation. It fully meets the stringent requirements of high efficiency and reliability for routine monitoring and large-scale screening of microplastic pollution in the water environment. Attached Figure Description

[0009] Figure 1 A schematic diagram of a high-throughput enrichment and rapid detection device for microplastic pollution in water bodies provided in this application; Figure 2 A schematic diagram of the structure of a specific labeling unit in a high-throughput enrichment and rapid detection device for microplastic pollution in water bodies provided in this application; Figure 3 A schematic diagram of the structure of a multimodal detection unit in a high-throughput enrichment and rapid detection device for microplastic pollution in water bodies, provided in this application; 1-Sample pretreatment unit; 2-Specific labeling unit; 3-Multimodal detection unit; 4-Intelligent control unit; 11-Microfluidic chip; 12-Field-controlled enrichment device; 31-Detection chamber; 32-Microscopic imaging component; 33-Raman spectroscopy component; 41-Central processing unit; 42-Sensor group; 111-Sample inlet; 112-Waste liquid outlet; 113-Main channel; 114-Secondary channel; 115-Microscale pores; 121-Electrode sheet; 122-Ring piezoelectric ceramic; 123-Acoustic field focuser; 221-Probe reservoir; 222-Selection valve; 223-Micro-injection pump; 321-High-resolution camera; 322-Long working distance objective lens; 331-Raman spectrometer; 332-Focusing lens group; 421-Enrichment monitoring sensor group; 422-Label monitoring sensor group; 423-Detection monitoring sensor group. Detailed Implementation

[0010] To further illustrate the technical means and effects adopted by the present invention for its intended purpose, exemplary embodiments will be described in detail below, examples of which are illustrated in the accompanying drawings. When referring to the drawings in the following description, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of methods and systems consistent with some aspects of this application as detailed in the appended claims.

[0011] The terminology used in this application is for descriptive purposes only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed purposes.

[0012] The following detailed description of the specific implementation methods, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided in detail.

[0013] Example 1

[0014] Please see Figures 1-3 This embodiment provides a high-throughput enrichment and rapid detection device for microplastic pollution in water, including a sample pretreatment unit 1, a specific labeling unit 2, a multimodal detection unit 3, and an independently set intelligent control unit 4.

[0015] The sample pretreatment unit 1 serves as the basic platform for microplastic enrichment and separation, including a microfluidic chip 11 and a field-controlled enrichment device 12. The microfluidic chip 11 is provided with a sample inlet 111 and a waste liquid outlet 112, which are used to introduce the water sample to be tested and to discharge the waste liquid after fractionation and enrichment, respectively. The field-controlled enrichment device 12 is disposed outside the tube wall of the microfluidic chip 11 and is used to perform non-destructive concentration and fractionation of microplastic particles in the water sample in the sample inlet 111. The microfluidic chip 11 adopts a multi-layer microchannel structure, including a main channel 113 and two sub-channels 114. The main channel 113 runs through the sample pretreatment unit 1, the specific labeling unit 2, and the multimodal detection unit 3. The sub-channels 114 are symmetrically distributed on both sides of the main channel 113 and are connected to the main channel 113 through microscale pores 115. The field-controlled enrichment device 12 acts at the intersection of the main channel 113 and the sub-channels 114, and controls the migration of microplastic particles between the main channel and the sub-channels by adjusting the electric field or acoustic field intensity. The field-controlled enrichment device 12 employs a composite enrichment structure of dielectric enrichment electrodes and acoustic enrichment transducers. The dielectric enrichment electrodes are disposed on the axial inner side of the field-controlled enrichment device and include at least three pairs of parallel electrode plates 121. A non-uniform electric field formed between adjacent electrode plates generates dielectric force for primary enrichment of passing microplastic particles. The acoustic enrichment transducer is disposed on the axial outer side of the field-controlled enrichment device and includes a ring-shaped piezoelectric ceramic 122 and an acoustic field focuser 123. The ring-shaped piezoelectric ceramic 122 and the acoustic field focuser 123 are concentrically arranged from the outside in. By exciting a sound field of a specific frequency and forming sound field nodes under the action of the acoustic field focuser 123, secondary enrichment is performed on nanoscale plastic particles. Specifically, the sample pretreatment unit utilizes a multi-layered microchannel structure of a microfluidic chip, including main channels, sub-channels, and microscale pores, combined with a field-controlled enrichment device. This enrichment technology incorporates a dielectrophoretic enrichment electrode and an acoustic enrichment transducer. The sample pretreatment unit employs a multi-layered microchannel structure of a microfluidic chip, combined with dielectrophoresis and acoustic enrichment techniques. Dielectrophoretic forces act on larger particles, while the acoustic focusing effect is more effective for nanoscale particles. This synergistic effect aims to achieve gentle and efficient concentration and fractionation of microplastics with a wide particle size range, reducing particle damage and loss caused by drastic physical operations in traditional methods. It achieves a fractional enrichment effect with a capture rate of over 95% for 1-1000 μm micrometer-sized particles and over 90% for 20 nm-1 μm nanometer-sized particles, providing a high-purity, high-resolution pre-treated sample basis for subsequent labeling and detection. The specific labeling unit 2 is located on the right side of the field-controlled enrichment device 12, including a labeling reaction chamber 21 and a probe injection device 22. The labeling reaction chamber (21) is a cylindrical cavity, coaxially sleeved on the outside of the tube wall of the microfluidic chip (11). An annular reaction space is formed between the inner wall of the labeling reaction chamber (21) and the outer wall of the microfluidic chip (11) for the specific probe solution to fully combine with the microplastic particles. The outlet end of the probe injection device 22 is connected to the main channel (113) of the microfluidic chip (11) through a feeding pipe for injecting specific Raman reporter probes into the flowing microplastic particles. Through this integrated design, the loss and contamination risk of microplastic particles caused by sample transfer in traditional offline labeling methods is solved, and in-situ labeling of enriched microplastics is realized.

[0016] The probe injection device 22 adopts a multi-channel switchable micro-injection structure, including a probe reservoir 221, a selection valve 222, and a micro-injection pump 223. The probe reservoir 221 is located above the labeling reaction chamber 21 and contains multiple independent chambers, each storing a specific probe solution corresponding to a different polymer. The selection valve 222 is located below the probe reservoir 221 and can be rotated to connect to different probe chambers. The micro-injection pump 223 is located on the connecting line between the selection valve 222 and the microfluidic chip 11, and can achieve quantitative injection of the probe solution by precisely controlling the injection volume and flow rate. Specifically, by integrating the labeling reaction chamber in the specific labeling unit with the microfluidic chip in a coaxial manner, and by using a multi-channel switchable micro-injection structure for the probe injection device, which includes a probe reservoir, a selection valve, and a micro-injection pump, the technical challenges of particle loss due to sample transfer, single probe type, and insufficient injection accuracy in traditional labeling methods have been solved. This has enabled in-situ labeling of enriched microplastics in the flow channel and precise and specific labeling of different polymer types, achieving a labeling success rate of over 98%, accurate labeling position, and controllable probe dosage. This lays a solid foundation for subsequent high signal-to-noise ratio optical detection. The multimodal detection unit 3 is located on the right side of the marking reaction chamber 21 and includes a detection chamber 31, a microscopic imaging component 32, and a Raman spectroscopy component 33. The detection chamber 31 is coaxially sleeved on the outside of the tube wall of the microfluidic chip 11. The microscopic imaging component 32 is vertically arranged above the detection chamber 31. The Raman spectroscopy component 33 is arranged radially along the right side of the detection chamber 31 and is used to simultaneously acquire morphological images and chemical composition spectra of a single particle inside the detection chamber 31. The microscopic imaging component 32 and the Raman spectroscopy component 33 employ a co-positioned, synchronously acquired optical path coupling structure. The microscopic imaging component 32 includes a high-resolution camera 321 and a long working distance objective lens 322. The long working distance objective lens 322 is vertically positioned directly above the detection chamber 31, with its optical axis passing through the detection chamber 31 and extending downwards. It is used to perform real-time morphological imaging of individual particles passing through a specific detection point, producing high-resolution morphological images including size, shape, and color. The Raman spectroscopy component 33 includes a Raman spectrometer 331 and a focusing lens group 332. The focusing lens group 332 is horizontally positioned on the right side of the detection chamber 31, with its optical axis passing through the detection chamber 31 and extending upwards. It orthogonally confociates with the optical axis of the long working distance objective lens 322 inside the detection chamber 31, forming a specific detection point. The optical paths of the microscopic imaging component 32 and the Raman spectroscopy component 33 form an orthogonal confociating structure at the specific detection point. Specifically, through the orthogonal confocal structure design of the multimodal detection unit, the vertical optical path of the microscopic imaging component includes a high-resolution camera and a long working distance objective lens, while the horizontal optical path of the Raman spectroscopy component includes a Raman spectrometer and a focusing lens group. These components form a precise orthogonal confocal detection point inside the detection chamber, solving the technical problem in traditional detection methods where morphological characterization and chemical composition analysis are independent and cannot simultaneously acquire complete information about the same particle. This enables the simultaneous acquisition and precise correlation of morphological characteristics such as size, shape, and color of individual microplastic particles with their polymer chemical composition. It achieves excellent results with a morphological detection resolution of 0.5 μm, a spectral detection limit of 1 μm, and 100% data acquisition synchronization, providing complete and reliable multimodal data support for the accurate identification and classification of microplastics. The intelligent control unit 4 is independently configured and includes a central processing unit 41 and a sensor group 42. The sensor group 42 has three sets of sensors, which are respectively located inside the field-controlled enrichment device 12, the labeling reaction chamber 21, and the detection chamber 31. The central processing unit 41 is electrically connected to the field-controlled enrichment device 12, the probe injection device 22, the microscopic imaging component 32, the Raman spectroscopy component 33, and the sensor group 42 via control cables to form a centralized control and coordinated regulation device. The sensor group 42 includes an enrichment monitoring sensor group, a labeling monitoring sensor group, and a detection monitoring sensor group. The enrichment monitoring sensor group is arranged side by side from left to right inside the field-controlled enrichment device 12, and includes a field strength sensor for monitoring field strength and a micro-flow sensor for monitoring flow rate. The labeling monitoring sensor group is arranged side by side from left to right inside the labeling reaction chamber 21, and includes a fluorescence intensity sensor for monitoring labeling effect and a pH sensor for monitoring reaction conditions. The detection monitoring sensor group is arranged adjacent to each other around specific detection points in the detection chamber 31, and includes an optical positioning sensor for triggering detection and an optical counter for counting particle concentration. Specifically, the centralized collaborative control device constructed through the intelligent control unit, in which the central processor 41 integrates the field strength sensor of the enrichment monitoring sensor group, the micro-flow sensor, the fluorescence intensity sensor of the labeling monitoring sensor group, the pH sensor, and the optical positioning sensor and optical counter of the detection monitoring sensor group to form a global perception network, and establishes real-time data interaction with each execution unit, solves the technical bottlenecks of independent operation of each unit, non-coordinated parameters, and reliance on human experience for process control in traditional detection devices, and realizes closed-loop intelligent control of microplastic enrichment intensity, labeling reaction conditions and optical detection parameters, achieving precise control effects such as completing parameter adaptive adjustment within 100 milliseconds, reducing the device error rate to below 3%, and fully automated operation of the entire process; The central processing unit 41 is configured to execute a multimodal data fusion algorithm; automatically classify and count particles based on real-time acquired morphological images and Raman spectral data; and dynamically adjust the operating parameters of each execution unit, including field-controlled enrichment intensity, probe injection rate and optical detection parameters, based on the real-time feedback of fluid data and optical data from the sensor group 42. Specifically, the multimodal data fusion algorithm establishes a particle feature database and automatically completes the particle classification and counting process based on real-time acquired morphological images and Raman spectral data. This includes: the central processing unit 41 receiving morphological image data from the microscopic imaging component 32 and spectral data from the Raman spectral component 33; the central processing unit 41 extracting particle size, shape, and color feature parameters and identifying the polymer type and chemical composition of the particles based on the morphological image data and Raman spectral data; associating and fusing the morphological and chemical features of the same particle to establish a multimodal particle feature database; automatically identifying the type and counting the number of microplastic particles using a classification algorithm based on the feature database; and outputting a detection report containing particle type distribution and concentration information based on the classification and statistical results. Through a closed-loop process of feature extraction, fusion, classification and optimization, the problem of low efficiency and high subjectivity caused by reliance on manual interpretation in traditional microplastic detection has been solved. It realizes automatic association and intelligent classification of morphological and chemical characteristics, achieving a classification accuracy of over 97% and a processing speed of over 50 particles per minute, significantly improving the automation level and reliability of the detection results.

[0017] Example 3

[0018] Please see Figures 1-3 This embodiment is applied to the analysis of microplastic pollution in a surface water sample. Its goal is to simultaneously detect the distribution characteristics of micron-sized and nano-sized plastic particles. The device is required to achieve fully automated analysis from enrichment and labeling to detection during continuous detection. The initial state is that the device is in standby mode, all units have completed preheating, and the fluid device has been started. The implementation process specifically includes: After the high-throughput enrichment and rapid detection device for microplastic pollution in water is started, the operator inputs the preset detection parameters through the operation interface of the intelligent control unit 4: sample injection flow rate 1.0 mL / min, dielectric field strength 150 V / mm, acoustic field frequency 2 MHz, probe injection rate 10 μL / min, imaging exposure time 50 ms, and spectral integration time 2 s. After receiving the instructions, the intelligent control unit 4 automatically activates each functional unit to maintain the stable operation of the internal fluid environment of the device. After the parameters are set, the operator triggers a one-button start command; the central processing unit 41 of the intelligent control unit 4 sends control signals to each unit, the sample pretreatment unit 1 continuously processes the water sample at the set flow rate, the field-controlled enrichment device 12 starts synchronously, and the dielectrophoresis electrode and the acoustic transducer work together to enrich the microplastics in the water sample in a graded manner. By precisely matching the dielectrophoresis field strength of 150V / mm with the acoustic field frequency of 2MHz, the technical problem of uneven capture efficiency of microplastics of different sizes in traditional enrichment methods is solved, realizing efficient capture of plastic particles of all sizes from micron to nano, achieving a graded enrichment effect with a capture rate of over 95% for 1-1000μm microplastics and over 90% for 20nm-1μm nanoplastics; The specific labeling unit 2 is then activated, and the probe injection device 22 precisely injects specific probes into the labeling reaction chamber 21 according to a preset program. Through precise control of the probe injection rate of 10 μL / min and the multi-channel switching structure, the problems of single probe usage and insufficient injection accuracy in the traditional labeling process are solved, achieving specific and accurate labeling of different polymer microplastics, and achieving a stable labeling effect with a labeling success rate of over 98% and a probe dosage error of less than ±2%. During the detection process, the central processing unit 41 of the intelligent control unit 4 can dynamically adjust the labeling strategy based on the preliminary Raman spectroscopy analysis results fed back in real time by the multimodal detection unit 3: when the central processing unit 41 identifies that the frequency and concentration of a specific type of microplastic polymer exceeds a preset threshold based on real-time and historical detection data analysis, it controls the selection valve (222) of the probe injection device (22) to rotate, switching the flow path from the current probe chamber to the specific probe chamber corresponding to the identified specific type of microplastic polymer; at the same time, it dynamically adjusts the injection parameters of the micro-injection pump (223) based on the identified field-controlled enrichment intensity, probe injection rate and optical detection parameters; the adjusted micro-injection pump (223) quantitatively injects the new specific probe solution into the labeling reaction chamber (21) to target and enhance the dominant pollutants; The multimodal detection unit 3 is activated simultaneously, and the microscopic imaging component 32 and the Raman spectroscopy component 33 simultaneously acquire morphological images and Raman spectra of the labeled individual microplastic particles. By precisely matching the imaging exposure time of 50ms and the spectral integration time of 2s, the technical bottleneck of asynchronous acquisition of morphological and chemical analysis is solved, and the synchronous acquisition of morphological features and chemical composition of the same microplastic particle is realized, achieving a high-quality detection effect with a morphological detection resolution of 0.5μm and a spectral signal-to-noise ratio of over 30dB. During the testing process, the intelligent control unit 4 monitors various process parameters in real time through the sensor group 42. When the dielectric field strength fluctuation exceeds ±5%, the central processing unit 41 adjusts the electrode output through the power adjustment unit within 100 milliseconds. When the probe injection rate deviation exceeds the set value, the propulsion speed of the micro-injection pump 223 is immediately adjusted. At the same time, the central processing unit 41 dynamically adjusts the coolant flow rate based on the temperature data of the sensor group 42 to ensure that the operating temperature of each optical component is stable within the range of 25±2℃. Through this real-time closed-loop control mechanism, the problems of non-coordination of unit parameters and reliance on manual experience in traditional testing are solved, realizing the automated intelligent control of the entire process and achieving a precise control effect with a false judgment rate of less than 3% and an operational stability of more than 99%. After running continuously for 8 hours, the intelligent control unit 4 automatically generates a detection and analysis report, including particle type distribution, concentration statistics, and size distribution map; all data is transmitted to the central control room via industrial Ethernet to realize real-time monitoring and data traceability of the detection process.

[0019] This embodiment successfully achieved rapid and accurate detection of microplastics in surface water samples, with a detection throughput of 60 samples / day. Its comprehensive performance indicators are superior to traditional detection methods, significantly improving the detection efficiency and accuracy of microplastics in water.

[0020] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A high-throughput enrichment and rapid detection device for microplastic pollution in water bodies, characterized in that: It includes a sample pretreatment unit (1), a specific labeling unit (2), and a multimodal detection unit (3) arranged from left to right, as well as an intelligent control unit (4) for unified control of each unit; The sample pretreatment unit (1) includes a microfluidic chip (11) and a field-controlled enrichment device (12); the microfluidic chip (11) is provided with a sample inlet (111) and a waste liquid outlet (112), which are used to introduce the water sample to be tested and to discharge the waste liquid after fractionation and enrichment, respectively; the field-controlled enrichment device (12) is disposed outside the tube wall of the microfluidic chip (11) and is used to perform non-destructive concentration and fractionation of microplastic particles in the water sample in the sample inlet (111) section; The specific labeling unit (2) is located on the right side of the sample pretreatment unit (1). The specific labeling unit (2) includes a labeling reaction chamber (21) and a probe injection device (22). The labeling reaction chamber (21) is coaxially sleeved on the outside of the tube wall of the microfluidic chip (11). The outlet end of the probe injection device (22) is connected to the main channel (113) of the microfluidic chip (11) through a feeding pipe, and is used to inject specific Raman reporter probes into the microplastic particles after non-destructive concentration and classification. The multimodal detection unit (3) is located on the right side of the specific labeling unit (2), and includes a detection chamber (31), a microscopic imaging component (32), and a Raman spectroscopy component (33). The detection chamber (31) is coaxially sleeved on the outside of the tube wall of the microfluidic chip (11). The microscopic imaging component (32) is vertically positioned above the detection chamber (31). The Raman spectroscopy component (33) is positioned radially along the right side of the detection chamber (31) and is used to simultaneously acquire morphological images and chemical composition spectra of microplastic particles after injection of specific Raman reporter probes. The intelligent control unit (4) is independently set up, including a central processing unit (41) and a sensor group (42); the sensor group (42) has three sets of sensors, which are respectively set inside the field-controlled enrichment device (12), the labeling reaction chamber (21) and the detection chamber (31); the central processing unit (41) is electrically connected to the field-controlled enrichment device (12), the probe injection device (22), the microscopic imaging component (32), the Raman spectroscopy component (33) and the sensor group (42) through control cables to form a centralized control and collaborative regulation device, which is used to coordinately adjust the enrichment field strength, probe injection parameters and optical detection parameters in real time based on sensor data.

2. The high-throughput enrichment and rapid detection device for microplastic pollution in water bodies according to claim 1, characterized in that, The microfluidic chip (11) adopts a multi-layer microchannel structure, including a main channel (113) and two sub-channels (114); the starting end of the main channel (113) is the sample inlet (111), and it runs through the sample pretreatment unit (1), the specific labeling unit (2) and the multimodal detection unit (3); the two sub-channels (114) have waste liquid outlets (112) at the end of the channel, and are symmetrically distributed on both sides of the main channel (113), and are connected to the main channel (113) through microscale pores (115); the field-controlled enrichment device (12) acts at the intersection of the main channel (113) and the sub-channels (114), and controls the migration of microplastic particles between the main channel and the sub-channel by adjusting the electric field or sound field intensity, so as to carry out the graded enrichment of microplastics of different particle sizes.

3. The high-throughput enrichment and rapid detection device for microplastic pollution in water bodies according to claim 2, characterized in that: The field-controlled enrichment device (12) adopts a composite enrichment structure of dielectric enrichment electrode and acoustic field enrichment transducer; The dielectric enrichment electrode is disposed on the axial inner side of the field-controlled enrichment device and includes at least three pairs of parallel electrode plates (121). Dielectrophoretic force is generated by the non-uniform electric field formed between adjacent electrode plates for primary enrichment of microplastic particles. The sound field enrichment transducer is located on the axial outer side of the field-controlled enrichment device, including an annular piezoelectric ceramic (122) and a sound field focuser (123); the annular piezoelectric ceramic (122) and the sound field focuser (123) are arranged concentrically from the outside to the inside, and a sound field node is formed by exciting a sound field of a specific frequency under the action of the sound field focuser (123) to perform secondary enrichment for nanoscale plastic particles.

4. The high-throughput enrichment and rapid detection device for microplastic pollution in water bodies according to claim 1, characterized in that: The probe injection device (22) adopts a multi-channel switchable micro-injection structure, including a probe reservoir (221), a selection valve (222), and a micro-injection pump (223); The probe reservoir (221) is located above the labeling reaction chamber (21), and its bottom has at least four independent chambers, which are used to store specific Raman reporter probe solutions for specific types of microplastic polymers. The selection valve (222) is located directly below the probe reservoir (221). The inlet end of the selection valve (222) is connected to the outlet end of the four independent chambers through four independent flow channels. The valve core is rotated to switch between different probe chambers. The inlet end of the micro-injection pump (223) is connected to the outlet end of the selection valve (222) via a connecting pipe. The outlet end is directly connected to the main channel of the microfluidic chip (11) to quantitatively inject the selected probe solution at a certain flow rate into the surface of the microplastic particles flowing through the labeling reaction chamber (21).

5. A high-throughput enrichment and rapid detection device for microplastic pollution in water bodies according to claim 4, characterized in that, The probe injection device (22) employs a multi-channel switchable micro-injection process, including: The central processing unit (41) is configured to monitor the frequency and concentration of specific types of microplastic polymers via a sensor array (42). When the frequency and concentration of a specific type of microplastic polymer are identified to exceed a preset threshold, the selection valve (222) of the probe injection device (22) is controlled to rotate, and the flow path is switched from the current probe chamber to the specific probe chamber corresponding to the identified specific type of microplastic polymer. Meanwhile, the injection parameters of the micro-injection pump (223) are dynamically adjusted based on the field-controlled enrichment intensity, probe injection rate and optical detection parameters identified by the central processing unit (41). The adjusted microinjection pump (223) quantitatively injects the new specific probe solution into the labeling reaction chamber (21) to target and enhance the dominant pollutant.

6. The high-throughput enrichment and rapid detection device for microplastic pollution in water bodies according to claim 1, characterized in that: The labeling reaction chamber (21) is a cylindrical cavity, coaxially sleeved on the outside of the tube wall of the microfluidic chip (11); the inner wall of the labeling reaction chamber (21) and the outer wall of the microfluidic chip (11) form an annular reaction space for the specific probe solution to fully combine with the microplastic particles.

7. The high-throughput enrichment and rapid detection device for microplastic pollution in water bodies according to claim 1, characterized in that: The microscopic imaging component (32) and the Raman spectroscopy component (33) adopt a co-positioned synchronous acquisition optical path coupling structure; The microscopic imaging component (32) includes a high-resolution camera (321) and a long working distance objective (322). The long working distance objective (322) is vertically positioned directly above the detection chamber (31), with its optical axis passing through the detection chamber (31) and extending downwards. It is used to perform real-time morphological imaging of individual particles passing through a specific detection point, including high-resolution morphological images of size, shape, and color. The Raman spectroscopy assembly (33) includes a Raman spectrometer (331) and a focusing lens group (332). The focusing lens group (332) is horizontally arranged on the right side of the detection chamber (31). Its optical axis passes through the detection chamber (31) and extends upward. It orthogonally confociates with the optical axis of the long working distance objective lens (322) inside the detection chamber (31) to form a specific detection point for synchronously acquiring the Raman spectral signal of the same particle. The optical paths of the microscopic imaging component (32) and the Raman spectroscopy component (33) form an orthogonal confocal structure at the specific detection point, which is used for the synchronous acquisition of the same particle morphology image and chemical composition spectrum.

8. The high-throughput enrichment and rapid detection device for microplastic pollution in water bodies according to claim 1, characterized in that: The sensors of the sensor group (42) of the intelligent control unit (4) include an enrichment monitoring sensor group (421), a label monitoring sensor group (422), and a detection monitoring sensor group (423). The enrichment monitoring sensor group (421) is arranged side by side from left to right inside the field control enrichment device (12), including a field strength sensor for monitoring field strength and a micro flow sensor for monitoring flow rate. The label monitoring sensor group (422) is arranged side by side from left to right in the labeling reaction chamber (21), including a fluorescence intensity sensor for monitoring the labeling effect and a pH sensor for monitoring the reaction conditions; The detection and monitoring sensor group (423) is arranged adjacent to each other around specific detection points in the detection chamber (31), and includes an optical positioning sensor for triggering detection and an optical counter for counting particle concentration.

9. A high-throughput enrichment and rapid detection device for microplastic pollution in water bodies according to claim 1, characterized in that: The central processing unit of the intelligent control unit (4) is configured to execute a multimodal data fusion algorithm; automatically complete particle classification and counting based on real-time acquired morphological images and Raman spectral data; the central processing unit (41) dynamically adjusts the operating parameters of each execution unit, including field-controlled enrichment intensity, probe injection rate and optical detection parameters, based on the fluid data and optical data fed back in real time by the sensor group (42).

10. A high-throughput enrichment and rapid detection device for microplastic pollution in water bodies according to claim 9, characterized in that, The multimodal data fusion algorithm establishes a particle feature database and automatically completes the particle classification and counting process based on real-time acquired morphological images and Raman spectral data, including: The central processing unit (41) of the intelligent control unit (4) receives morphological image data from the microscopic imaging component (32) and spectral data from the Raman spectroscopy component (33); the central processing unit (41) extracts the size, shape and color feature parameters of the particles and identifies the polymer type and chemical composition of the particles based on the morphological image data and Raman spectral data respectively; it correlates and fuses the morphological features and chemical features of the same particle to establish a multimodal particle feature database; based on the feature database, it automatically completes the type identification and quantity statistics of microplastic particles using a classification algorithm; the central processing unit (41) outputs a detection report containing particle type distribution and concentration information based on the classification statistics results.

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