Device for Rapidly Detecting Soil Organic Matter on Site and Detection Method Thereof

Abstract

The present invention relates to a method for rapid on-site detection of soil organic matter, and a detection device and chip used in combination therewith. The rapid detection device includes a pretreatment module, a centrifugal system, a microchannel chip, and a photoelectric detection module. The pretreatment module processes a soil sample to obtain a soil sample solution. The centrifugal system generates centrifugal force. The microchannel chip flows, mixes, and leaches the soil sample solution and the leaching solvent under the action of the centrifugal force of the centrifugal system to obtain a leachate. The photoelectric detection module detects the leachate to measure the content of organic matter in the soil sample solution. The centrifugal microchannel chip includes a channel layer, a cover plate layer provided above the channel layer, and a bottom plate layer provided below the channel layer. The present invention has the advantages of realizing rapid on-site detection of soil organic matter, a short detection period, high detection efficiency, and simple and convenient operation.

Description

Technical Field

[0001] The present invention relates to the technical field of detecting soil organic matter, and specifically to an apparatus for rapidly detecting soil organic matter on-site, its detection method, and a microfluidic chip.

Background Art

[0002] In modern agricultural production, scientific management of production and fertilization for food production increase is an important issue that needs to be urgently solved. Organic matter is an important part of the soil, an important indicator for measuring soil fertility, and provides the nutrients necessary for crops to survive. Measuring the content of soil organic matter, grasping the state of soil fertility, replenishing soil nutrients by accurate fertilization, improving soil fertility, and thereby ensuring crop yield and quality.

[0003] In the detection of soil organic matter content, conventional chemical methods such as potassium dichromate volumetric method, dry combustion method, and calcination method are often used. These conventional laboratory methods require complicated manual operations for soil samples, have low efficiency, high cost, long cycle, expensive detection equipment with large volume, and require regular maintenance, and are not suitable for rapid detection in the agricultural field. With the development of science and technology, rapid estimation research on soil nutrients using near-infrared, remote sensing, and hyperspectral technologies has attracted attention in recent years. In these methods, it is necessary to construct an estimation model for soil organic matter content. However, since there are many types of soil and it is necessary to establish multiple soil organic matter models, the current requirements for rapid and accurate model construction cannot be met.

[0004] Microfluidic technology, as a new analysis platform, has advantages such as miniaturization, automation, integration, convenience, and high speed, and is widely used in the field of detection. However, the centrifugal microfluidic analysis technology that uses wafer-shaped chips, drives the microfluid of the sample by centrifugal force, and simultaneously detects multiple samples has not yet made progress in the rapid detection of soil organic matter on-site.

[0005] Therefore, there is a need for a reliable detection method and related chip that are low in cost and can quickly detect soil organic matter at the agricultural site. SUMMARY OF THE INVENTION

[0006] An object of the present invention is to provide an apparatus for quickly detecting soil organic matter on-site, a detection method thereof, and a microfluidic chip. This quick detection apparatus, its detection method, and the microfluidic chip can solve the defects of the prior art, realize the quick detection of soil organic matter on-site, have advantages such as a short detection cycle, high detection efficiency, and simple operation.

[0007] To achieve the above object, the following technical means are adopted.

[0008] An apparatus for quickly detecting soil organic matter on-site, including a pretreatment module, a centrifugal system, a microfluidic chip, and a photoelectric detection module, wherein the pretreatment module is for processing a soil sample to obtain a soil sample solution, the centrifugal system is for generating a centrifugal force, the microfluidic chip is for flowing, mixing, and leaching a soil sample solution and a leaching solvent inside under the action of the centrifugal force generated by the centrifugal system to obtain a leachate, and the photoelectric detection module is for detecting the leachate and measuring the content of organic matter in the soil sample solution.

[0009] Furthermore, the apparatus includes a microprocessor module, a heating plate, a temperature control module, a drive module, a display, a power supply module, a communication module, and a display.

[0010] The heating plate is provided below the microchannel chip and heats the microchannel chip. The temperature control module controls the heating temperature of the heating plate. The drive module drives the operation of the centrifugal system. The power supply module supplies power to the microprocessor module. The communication module is used for communication between the microprocessor module and other equipment. The display displays the detection results of the photoelectric detection module. The microprocessor module acquires and analyzes the measurement results of the photoelectric detection module, displays the analysis results on the display, and controls the drive module and the temperature control module.

[0011] Furthermore, the pretreatment module is also used to process the solvent solution to obtain the leaching solvent. The leaching solvent includes a leaching agent and other solvents that promote leaching.

[0012] Furthermore, the centrifugal system employs a centrifugal detector.

[0013] Furthermore, the microchannel chip includes a channel layer and a cover plate layer provided above the channel layer. The channel layer includes a channel layer body and a plurality of channel branches provided on the channel layer body. The channel branches include a second solvent injection port, a sample introduction port, an extraction cell, a microchannel, a filtration cell, a detection cell, a waste liquid cell, and a second vent hole. The inlet of the extraction cell is connected to the second solvent injection port and the sample introduction port respectively. The outlet of the extraction cell is connected to the inlet of the microchannel. The outlet of the microchannel is connected to the inlet of the filtration cell. The outlet of the filtration cell is connected to the inlet of the detection cell. The outlet of the detection cell is connected to the inlet of the waste liquid cell. The waste liquid cell communicates with the second vent hole. A plurality of heating columns are provided in the extraction cell. A microarray and a plurality of microspheres are provided in the filtration cell. The microspheres are located above the microarray. A filtration pad is provided at the outlet of the filtration cell.

[0014] Furthermore, a first mounting hole, a plurality of sample introduction holes, a plurality of first solvent inlets, and a plurality of first ventilation holes are formed in the cover plate layer. A second mounting hole corresponding to the position of the first mounting hole is formed in the center of the passage layer body. The number of the sample introduction holes, the first solvent inlets, the first ventilation holes, and the passage branches is the same, and they are provided in a one-to-one correspondence. The sample introduction holes are provided corresponding to the sample inlets, the first ventilation holes are provided corresponding to the second ventilation holes, and the first solvent inlets are provided corresponding to the second solvent inlets.

[0015] Furthermore, a visible window is provided in the cover plate layer. The visible window includes a through hole formed in the cover plate layer and a light transmissive film attached to the through hole.

[0016] Furthermore, a bottom plate layer is provided below the passage layer, and a third mounting hole is attached to the center of the bottom plate layer.

[0017] Furthermore, the filter pad has at least one layer, and the filter pad is a combination of any one or more of a metal filter mesh, a filter cloth made of a non-metallic material, and a filter membrane.

[0018] The present invention also relates to a detection method using the above rapid detection device. The method package includes: Step (1) of processing a soil sample by a pretreatment module to obtain a soil sample solution; Step (2) of injecting the soil sample solution and the leaching solvent into the microchannel chip; Step (3) of heating the microchannel chip by a heating plate; Step (4) in which the centrifugal system operates, and under the drive of the centrifugal force generated by the centrifugal system, the soil sample solution and the leaching solvent in the microchannel chip flow along the passage branch, and the two are mixed and leached while flowing to obtain a leachate; Step (5) of detecting the leachate by a photoelectric detection module and measuring the content of organic matter in the soil sample solution; and includes.

[0019] According to the present invention, there is provided a centrifugal microfluidic chip including a channel layer, a cover plate layer provided above the channel layer, and a bottom plate layer provided below the channel layer, wherein the channel layer includes a channel layer main body and a plurality of channel branches provided on the channel layer main body, the channel branches include a sample inlet, an extraction cell, a microchannel, a filtration cell, a detection cell, and a waste liquid cell, an inlet of the extraction cell is connected to the sample inlet, an outlet of the extraction cell is connected to an inlet of the microchannel, an outlet of the microchannel is connected to an inlet of the filtration cell, an outlet of the filtration cell is connected to an inlet of the detection cell, and an outlet of the detection cell is connected to an inlet of the waste liquid cell. Further provided is a centrifugal microfluidic chip.

[0020] Furthermore, a plurality of heating columns are provided in the extraction cell.

[0021] Furthermore, a microarray and a plurality of microspheres are provided in the filtration cell. The microspheres are located above the microarray, and a filtration pad is provided at an outlet of the filtration cell.

[0022] Furthermore, a first mounting hole, a plurality of sample introduction holes, a plurality of first solvent inlets, and a plurality of first ventilation holes are opened in the cover plate layer.

[0023] Furthermore, the channel branch further includes a second ventilation hole communicating with the waste liquid cell and a second solvent inlet connected to an inlet of the extraction cell. A second mounting hole corresponding to the position of the first mounting hole is opened in the center of the channel layer main body. The sample introduction holes, the first solvent inlets, the first ventilation holes, and the channel branches are the same in number and are provided in one-to-one correspondence. The sample introduction holes are provided corresponding to the sample inlets, the first ventilation holes are provided corresponding to the second ventilation holes, and the first solvent inlets are provided corresponding to the second solvent inlets.

[0024] Furthermore, a visible window is opened in the cover plate layer. The visible window includes a through hole opened in the cover plate layer and a light transmissive film attached to the through hole.

[0025] Furthermore, a third mounting hole is formed in the center of the bottom plate layer.

[0026] Furthermore, the passage layer includes a first passage layer and a second passage layer provided in sequence, The upper half of the passage branch is located in the first passage layer, and the lower half of the passage branch is located in the second passage layer. The upper half of the passage branch penetrates through the first passage layer and communicates with the passage branch in the second passage layer.

[0027] Furthermore, the filter pad is at least one layer, and the filter pad is a combination of any one or more of a metal filter mesh, a filter cloth made of a non-metallic material, and a filter membrane.

[0028] According to the present invention, Step (1) of creating a microscopic structure image on the cover plate layer, the passage layer, and the bottom plate layer by computer software; Step (2) of processing so that the necessary microscopic structure is formed on the cover plate layer, the passage layer, and the bottom plate layer by microfabrication technology; Step (3) of aligning, bonding, and pressure-sealing the cover plate layer, the passage layer, and the bottom plate layer by bonding technology and assembling them into a centrifugal microchannel chip; Furthermore, a method for manufacturing the centrifugal microchannel chip including the above is provided.

[0029] Compared with the prior art, the present invention has the following advantages.

[0030] (1) In the present invention, by combining a microchannel chip and an automated portable device, complete integration and automation of chemical reactions and detection of soil organic matter are realized, the operation is simple, miniaturization is easy, and the requirement that even non-experts can quickly detect soil organic matter in large samples on-site can be satisfied.

[0031] (2) In the present invention, the leaching, reaction, separation, and color development processes of soil organic matter are carried out inside the microchannel chip, with a small amount of required sample and solvent, low cost, and high detection efficiency. With the centrifugal microchannel chip, multiple samples can be analyzed simultaneously, especially suitable for the detection of a large number of samples. Different channel branches can be applied to the detection and analysis of different samples.

[0032] (3) The leaching process of soil organic matter with an alkaline solution requires heating. In the present invention, a heating plate is provided at the lower part of the microchannel chip, and a heating column structure made of a metal material is provided in the extraction cell of the microchannel chip, so that the solution can be quickly heated to a predetermined temperature, thereby improving the leaching effect and the accuracy of detection.

[0033] (4) Regarding the design of the microchannel chip structure, in the present invention, a filtration cell structure is added between the extraction cell and the detection cell, a microarray and a plurality of microspheres with different sizes are provided in the filtration cell, a filtration pad is provided at the outlet of the filtration cell, and through the mutual cooperation of the microspheres, the microarray, and the filtration pad, fine particles in the liquid to be detected are effectively removed, the interference of impurities on subsequent detection is avoided, and the accuracy and reliability of the detection result are effectively improved.

Brief Description of the Drawings

[0034]

Figure 1

Figure 2

Figure 2-1

Figure 3

Figure 4

Figure 4-1

Figure 5

Figure 6

[0035] Explanation of symbols 1. Microprocessor module; 2. Centrifugal system; 3. Pretreatment module; 4. Photoelectric detection module; 5. Temperature control module; 6. Display; 7. Power supply module; 8. Communication module; 9. Microchannel chip; 10. Heating plate; 11. Drive module; 901. Cover plate layer; 902. Passage layer; 903. Passage bifurcation; 904. First vent hole; 905. Sample introduction hole; 906. First solvent injection port; 907. Sample inlet; 908. Second solvent injection port; 909. Heating column; 910. Extraction cell; 911. Microchannel; 912. Microarray; 913. Microsphere; 914. Filter pad; 915. Filter cell; 916. Detection cell; 917. Waste liquid cell; 918. Second vent hole.

Embodiments for Carrying Out the Invention

[0036] The present invention will be further described with reference to the following drawings. The on-site rapid detection device for soil organic matter shown in FIG. 1 includes a pretreatment module 3, a centrifugal system 2, a microchannel chip 9, a photoelectric detection module 4, a microprocessor module 1, a heating plate 10, a temperature control module 5, a drive module 11, a display 6, a power supply module 7, a communication module 8, and a display 6. The on-site rapid detection device for soil organic matter of the present invention has the functions of soil pretreatment, sample introduction, reaction of the soil sample solution and the leaching solvent, and analysis and detection of the reaction results, and can realize the operation of the microchannel chip and the on-site rapid analysis of soil organic matter. The present invention can realize the automatic, rapid, and accurate detection of soil organic matter based on the colorimetric detection principle of organic matter.

[0037] The pretreatment module 3 processes the soil sample to obtain a soil sample solution and is also used to process the leaching solvent to obtain a leaching solvent solution. The pretreatment module includes a through valve, a sample loop, a soil sample treatment device, a solvent treatment device, a scale, and a waste liquid treatment device. The scale is used for weighing. The through valve is used for sample introduction. The sample loop is used for quantification. The soil sample treatment device is used to turn the soil sample into a soil sample solution. The solvent treatment device is used for the preparation of the solvent. The waste liquid treatment device is used for the treatment of waste liquid.

[0038] The centrifugal system 2 is used for generating centrifugal force. The centrifugal system employs a centrifugal detector. The drive module is used to drive the operation of the centrifugal system. The centrifugal system and the drive module use a rotating tray and a centrifugal microfluidic solvent tray to achieve accurate control and transfer of the fluid in the microchannel chip by centrifugal force drive.

[0039] The microchannel chip 9 is used to make the soil sample solution and the leaching solvent flow, mix, and leach inside it under the action of the centrifugal force generated by the centrifugal system.

[0040] The photoelectric detection module 4 is used to detect the reaction result of the soil sample solution and the leaching solvent and measure the organic matter content in the soil sample solution. The photoelectric detection module 4 includes a light source and a photoelectric sensor. The absorbance is measured for the detection area (color development area) on the microchannel chip 9, and the signal detected by the photoelectric detection module 4 is input into the microprocessor module 1 for data processing to obtain the detection result. The organic matter content of the soil is measured based on the detection result, and the accurate detection result is displayed on the display 6 or the data is stored and printed by the communication module 8.

[0041] The heating plate 10 is provided below the microchannel chip 9 and is used to heat the microchannel chip 9. The temperature control module 5 is used to control the heating temperature of the heating plate 10. The temperature control module 5 controls the temperature of the entire microchannel chip by providing the heating plate 10 and a temperature sensor at the bottom of the microchannel chip 9.

[0042] The power supply module 7 supplies power to the microprocessor module 1.

[0043] The communication module 8 is used for communication between the microprocessor module 1 and other equipment.

[0044] The display 6 displays the detection results of the photoelectric detection module.

[0045] The microprocessor module 1 acquires and analyzes the measurement results of the photoelectric detection module 4, and displays the analysis results on the display 6. It is also used for the control of the drive module 11 and the temperature control module 5. The microprocessor module 1, the communication module 8, and the display 6 perform control, data acquisition, detection and analysis, result display and printing, and transmission processing for the entire device.

[0046] Microfluidics enables the integration of basic operation units such as sample preparation, reaction, separation, and detection into micron- and nanometer-scale components on a single microchip, thereby realizing the complete process of analytical detection. Since the microfluidic chip requires less sample and solvent, has low cost, and high detection efficiency, it has advantages such as miniaturization, automation, integration, convenience, and rapidity as a new analytical platform and is widely used in the field of detection. In the present invention, by using microfluidic chip technology for soil organic matter detection, a fully automated, rapid, and convenient detection platform and analysis method are developed, which can significantly shorten the sample processing time and minimize the costs of solvents and equipment. While ensuring accurate detection throughout the process, a smart and rapid detection of "results are obtained when the sample is introduced" is achieved, enabling on-site, rapid, and accurate analysis and measurement of soil organic matter, which has great significance for solving the problem of rapid on-site detection.

[0047] The centrifugal microfluidic chip includes a channel layer, a cover plate layer provided above the channel layer, and a bottom plate layer provided below the channel layer. The channel layer includes a channel layer body and a plurality of channel branches provided on the channel layer body. The channel branches include a sample inlet, an extraction cell, a microchannel, a filtration cell, a detection cell, and a waste liquid cell. The inlet of the extraction cell is connected to the sample inlet, the outlet of the extraction cell is connected to the inlet of the microchannel, the outlet of the microchannel is connected to the inlet of the filtration cell, the outlet of the filtration cell is connected to the inlet of the detection cell, and the outlet of the detection cell is connected to the inlet of the waste liquid cell.

[0048] Figure 2 is a schematic diagram of the microfluidic chip 9 according to Embodiment 1 of the present invention. The microfluidic chip 9 is formed by bonding and connecting a plurality of layers of circular sheet-like structures. The microfluidic chip 9 includes a channel layer 902 and a cover plate layer 901 provided above the channel layer 902.

[0049] As shown in FIG. 2-1, in Example 2, a bottom plate layer 919 of one layer may be further provided below the passage layer 902 to reinforce the structure of the passage layer. To facilitate processing, the passage layer 902 can be designed with a two-layer structure in which the upper layer is the first passage layer 9021 and the lower layer is the second passage layer 9022.

[0050] As shown in FIGS. 4, 4-1, 5, and 6, the passage layer 902 includes a passage layer body and a plurality of passage branches 903 provided on the passage layer body. By controlling the centrifugal force, the soil sample solution and the leaching solvent can be accurately controlled and transferred inside the microchannel chip 9, and the mixing, reaction, separation, and color development of the soil sample solution and the leaching solvent can be realized.

[0051] FIG. 4 is a schematic structural diagram of the passage layer 902 (the second passage layer 9022 of Example 2) according to Example 1 of the present invention. FIG. 4-1 is a schematic structural diagram of the first passage layer 9021 according to Example 2 of the present invention.

[0052] As can be seen from FIGS. 2, 3, 4, 4-1, 5, and 6, in Example 1, the passage layer 902 has a one-layer structure, while in Example 2, the passage layer 902 may be designed with a two-layer structure including the upper first passage layer 9021 and the lower second passage layer 9022.

[0053] The upper half of the channel bifurcation 903 is located in the first channel layer 9021, and the lower half of the channel bifurcation is located in the second channel layer 9022. The upper half of the channel bifurcation 903 penetrates through the first channel layer and communicates with the channel bifurcation in the second channel layer. The channel bifurcation 903 includes a second solvent injection port 908, a sample introduction port 907, an extraction cell 910, a microchannel 911, a filtration cell 915, a detection cell 916, a waste liquid cell 917, and a second vent hole 918. The inlet of the extraction cell 910 is connected to the second solvent injection port 908 and the sample introduction port 907 respectively, the outlet of the extraction cell 910 is connected to the inlet of the microchannel 911, the outlet of the microchannel 911 is connected to the inlet of the filtration cell 915, the outlet of the filtration cell 915 is connected to the inlet of the detection cell 916, the outlet of the detection cell 916 is connected to the inlet of the waste liquid cell 917, and the waste liquid cell 917 communicates with the second vent hole 918. By controlling the centrifugal force, the soil sample solution and the leaching solvent can be accurately controlled and transferred inside the microchannel chip, and the mixing, reaction, separation, and color development of the soil sample solution and the leaching solvent can be realized.

[0054] A plurality of heating columns 909 are provided in the extraction cell 910. The heating column 909 heats the mixture of the sample and the leaching solvent in the extraction cell 910. The sample and the solvent can react more fully in the extraction cell under heating conditions. The heating plate heats the entire microchannel chip and the liquid inside it, ensuring sufficient reaction of the mixed liquid throughout the process.

[0055] The filtration cell 915 is provided with a microarray 912 and a plurality of microspheres 913 of different sizes. The microspheres 913 are located above the microarray 912. The microarray 912 can be directly processed into a square micropillar array in the filtration cell 915. The filtration cell 915 may be provided with a microarray or a plurality of microspheres alone, or may combine both structures. In addition, a filtration pad 914 is provided at the outlet of the filtration cell 915. The filtration pad 914 may be a metal filter net, a non-metal filter cloth, a filter membrane, or any combination thereof, and may be arbitrarily combined as necessary, and may be one layer or multiple layers. The number of microspheres 913 is multiple. The multiple microspheres 913 are randomly arranged in the filtration cell 915. The sizes of each microsphere 913 are different. The microspheres 913 are any one of an in situ synthesized organic polymer, a PS microsphere (polystyrene), and a silica microsphere. The microarray 912, the microspheres 913, and the filtration pad 914 cooperate with each other to effectively remove particles in the test liquid. The filtration cell 915 performs secondary filtration of the test leaching solution through the filtration structure of the microarray 912, the microspheres 913, and the filtration pad 914, thereby effectively removing particles of different sizes in the leaching solution and improving the accuracy of the detection result.

[0056] During detection, the sample solution is introduced from the sample inlet 905, and the leaching solvent is introduced from the first solvent inlet 906 and the second solvent inlet 908, and passes through the output cell 910, the filtration cell 915, and the detection cell 916 in order along the microchannel 911 to complete the color reaction of the solution. The solvent may be in a liquid state or a solid state. In the liquid state, the solvent can be sealed inside the microchannel chip 9 by pressurized introduction or in the form of a liquid sac in the pretreatment module 3. In the solid state, the solvent can be sealed inside the microchannel chip 9 in a powder or lump form.

[0057] As shown in FIG. 3, the cover plate layer 901 is provided with a first mounting hole, a plurality of sample introduction holes 905, a plurality of first solvent inlets 906, and a plurality of first ventilation holes 904. A second mounting hole corresponding to the position of the first mounting hole is opened in the center of the passage layer body. A third mounting hole is opened in the center of the bottom plate layer. The first mounting hole, the second mounting hole, and the third mounting hole are provided corresponding to each other and are used for mounting the microchannel chip to the centrifuge detector.

[0058] The number of the sample introduction holes 905, the first solvent inlets 906, the first ventilation holes 904, and the passage branches 903 is the same, and they are provided in a one-to-one correspondence. The sample introduction hole 905 is provided corresponding to the sample inlet 907, and the two are in communication. The soil sample solution is added from the sample introduction hole 905, and the soil sample solution flows along the sample introduction hole 905 to the sample inlet 907. The first ventilation hole 904 is provided corresponding to the second ventilation hole 918 and is used for the communication between the inside of the passage branch 903 and the external atmosphere and for maintaining the pressure balance. The first solvent inlet 906 is provided corresponding to the second solvent inlet 908, and the two are in communication. The solvent is added from the first solvent inlet 906, and the solvent flows along the first solvent inlet 906 to the second solvent inlet 908.

[0059] Furthermore, a visible window is provided in the cover plate layer 901. The visible window includes a through hole opened in the cover plate layer and a light transmissive film attached to the through hole. The detection light from the optical detection module 4 passes through the visible window to optically detect the reaction result in the detection cell.

[0060] Manufacture and usage method of the above-mentioned centrifugal microchannel chip (1) Use computer-aided design software to design and draw the fine structure of each layer of the chip in the centrifugal microchannel chip. The fine structure includes structures such as ventilation holes, mounting holes, sample inlets, microchannels, extraction cells, filtration cells, detection cells, and waste liquid cells.

[0061] (2) Use microfabrication technology to process and manufacture the necessary fine structure on the surface of the base material of each layer of the microchannel chip such as the cover plate layer, the passage layer, and the bottom plate layer.

[0062] (3) Pour the leaching agent into the reaction cell or inject the leaching agent through the solvent inlet when detecting.

[0063] (4) Align, bond, and press-seal the centrifugal microchannel chip of each layer such as the cover plate layer, the channel layer, and the bottom plate layer by an adhesion technique, and assemble them to form a centrifugal microchannel chip.

[0064] (5) After sealing the chip, add the test sample solution to the sample introduction hole.

[0065] (6) Attach the centrifugal microchannel chip to the centrifuge through the mounting hole, start the centrifuge, and the test sample solution and the leaching agent are mixed, reacted, and separated in the extraction cell under the action of centrifugal force.

[0066] (7) Change the centrifugal speed of the centrifuge, and the leachate enters the filtration cell from the extraction cell through the microvalve, and solid-liquid separation is performed in this filtration cell. The microvalve is attached between the extraction cell and the filtration cell.

[0067] (8) Change the centrifugal speed of the centrifuge again, and the filtered clear liquid enters the detection cell through the microvalve. This microvalve is provided between the filtration cell and the detection cell.

[0068] (9) After processing the sample, detect the extraction solution with a photodetector to obtain the organic matter content.

[0069] The operation process of the microchannel chip of the present invention is as follows. When detecting soil organic matter with the microchannel chip 9, the soil sample solution is injected into the microchannel chip 9 from the sample introduction hole 905, flows from the sample introduction hole 905 to the sample inlet 907, and the solvent is injected or embedded into the first solvent inlet 906 and the second solvent inlet 908 from the first solvent inlet 906.

[0070] This centrifugal microfluidic chip is used to detect soil organic matter. This centrifugal microfluidic chip is a circular sheet-shaped chip composed of multiple layers of chips. Under the drive of centrifugal force caused by rotation, the mixing, reaction, separation, and color development processes of the test sample and the reaction reagent are realized. Finally, the content of organic matter in the soil sample is quantitatively detected by an ultraviolet-visible spectrophotometer. Such a centrifugal microfluidic chip for detecting soil organic matter has the advantages of requiring less amount of sample and reagent, being able to process and detect multiple samples simultaneously, and being rapid and convenient.

[0071] Under the action of centrifugal force by the centrifugal system, the soil sample solution in the sample inlet 907 flows into the extraction cell 910, and the soil sample solution and the leaching solvent are mixed. The heating column 909 in the extraction cell 910 heats the mixture of the soil sample solution and the leaching solvent flowing into the extraction cell 910, so that the leaching rate of the soil sample solution and the solvent becomes faster. The soil sample solution and the solvent are leached in the extraction cell and continue to move forward under the action of the centrifugal force of the centrifugal system 2, and flow in the spiral or reciprocatingly bent microchannel 911 and continue to be leached. By designing the microchannel 911 in a spiral or reciprocatingly bent shape, the soil sample solution and the solvent can be leached sufficiently.

[0072] Using centrifugal force as the driving force of the sample microfluid, and precisely controlling and transferring the microfluid, the mixing, reaction, separation, and color development processes of the sample and the reaction reagent in the chip are realized. Finally, the content of organic matter in the sample on the chip is qualitatively and quantitatively detected by a photodetector, and rapid detection of soil organic matter on-site can be realized, which has the advantages of short detection cycle, high detection efficiency, simple and convenient operation, etc.

[0073] When the mixed solution of the soil sample solution and the solvent flows to the filtration cell, the mixed solution moves forward horizontally and filters out the excess particulate matter in the mixed solution by the microspheres 913 and the microarray 912. On the other hand, the mixed solution moves from top to bottom. In the process of moving from top to bottom, first, the excess particles are filtered by the microspheres 913, and then the particulate matter therein is filtered by the microarray 912. When the mixed solution flows to the filter pad 914 at the outlet of the filtration cell 915, the filter pad 914 further filters the mixed solution and filters out the excess particulate matter therein. Through multiple filtrations by the microarray 912, the microspheres 913 and the filter pad 914, the excess particulate matter in the mixed solution is removed as much as possible, and the accuracy of the detection result is ensured.

[0074] The mixed solution after multiple filtration treatments flows into the detection cell 916, and the leachate is detected by the photoelectric detection module 4 to determine the organic matter content in the soil. The liquid after detection flows into the waste liquid cell. In the process of the flow of the mixed solution, leaching always occurs in the soil sample solution and the solvent.

[0075] The present invention also relates to a detection method using the above rapid detection device. This method includes the following steps. (1) Treat the soil sample by the pretreatment module 3 to obtain a soil sample solution.

[0076] (2) Inject the soil sample solution and the leaching solvent into the microchannel chip 9.

[0077] (3) Heat the microchannel chip 9 by the heating plate 10.

[0078] (4) The centrifugal system 2 operates. Due to the driving of the centrifugal force by the centrifugal system 2, the soil sample solution and the leaching solvent in the microchannel chip 9 flow along the passage branch 903. During the flowing process, the two are mixed and leached to obtain a leaching solution. The centrifugal system is started, and the test sample solution and the leaching agent are mixed, reacted, and separated in the extraction cell under the action of the centrifugal force. The centrifugal speed of the centrifugal system is changed, and the leaching solution enters the filtration cell from the extraction cell through the microvalve, and solid-liquid separation is performed in this filtration cell. This microvalve is installed between the extraction cell and the filtration cell. The centrifugal speed of the centrifugal system is changed again, and the filtered clear liquid enters the detection cell through the microvalve. This microvalve is provided between the filtration cell and the detection cell.

[0079] (5) The photoelectric detection module 4 detects the leaching solution to measure the content of organic matter in the soil sample solution.

[0080] The present invention further has the following advantages.

[0081] (1) In the present invention, by combining a microchannel chip and an automated portable device, the complete integration and automation of the chemical reaction and detection of soil organic matter are realized. The operation is simple, miniaturization is easy, and the requirement that even non-experts can quickly detect the soil organic matter of a large number of samples on-site can be satisfied.

[0082] (2) In the present invention, the leaching, reaction, separation, and color development processes of soil organic matter are carried out inside the microchannel chip. The amount of the required sample and solvent is small, the cost is low, and the detection efficiency is high. With the centrifugal microchannel chip, a plurality of samples can be analyzed simultaneously, which is particularly suitable for the detection of a large number of samples. Different passage branches can be applied to the detection and analysis of different samples.

[0083] (3) The leaching process of soil organic matter in an alkaline solution requires heating. In the present invention, a heating plate is provided below the microchannel chip, and a heating column structure made of a metal material is provided in the extraction cell of the microchannel chip, so that the solution can be quickly heated to a predetermined temperature, thereby improving the leaching effect and the accuracy of detection.

[0084] (4) In the present invention, the structure of a centrifugal microchannel chip is adopted, and centrifugal force is used as the driving force for the sample microfluid, and the mixing, extraction, and detection processes of the test sample and the leaching agent are carried out. Compared with the prior art, with this microchannel chip and method, a plurality of samples can be processed and detected simultaneously, the required amounts of samples and reagents are small, the complete integration and automation of chemical reactions and detection are realized, and it has advantages such as being economical, rapid, portable, and efficient. It provides a new analysis technology platform for the detection of soil organic matter and can meet the requirement of quickly detecting soil organic matter on-site.

[0085] (5) In the present invention, the leaching, reaction, separation, and color development processes of soil organic matter are carried out inside the microchannel chip. The required amounts of samples and solvents are small, the cost is low, and the detection efficiency is high. With the centrifugal microchannel chip, a plurality of samples can be analyzed simultaneously, and it is particularly suitable for the detection of a large number of samples. Different channel branches can be applied to the detection and analysis of different samples.

[0086] (6) The leaching process of soil organic matter in an alkaline solution requires heating. In the present invention, a heating plate is provided below the microchannel chip, and a heating column structure made of a metal material is provided in the extraction cell of the microchannel chip, so that the solution can be quickly heated to a predetermined temperature, thereby improving the leaching effect and the accuracy of detection.

[0087] (7) Regarding the design of the microchannel chip structure, in the present invention, a filtration cell structure is added between the extraction cell and the detection cell. A microarray and a plurality of microspheres with different sizes are provided in the filtration cell, and a filtration pad is provided at the outlet of the filtration cell. Through the mutual cooperation of the microspheres, the microarray, and the filtration pad, the particles in the liquid to be detected are effectively removed, the interference of impurities to subsequent detection is avoided, and the accuracy and reliability of the detection results are effectively improved.

[0088] The above embodiments are only descriptions of the preferred embodiments of the present invention and do not limit the scope of the present invention. Without departing from the design concept of the present invention, those skilled in the art can make various modifications and improvements to the technical means of the present invention, and all of these should be included in the protection scope specified by the claims of the present invention.

Claims

1. An apparatus for rapidly detecting soil organic matter on-site, comprising a pretreatment module, a centrifugal system, a microfluidic chip, and a photoelectric detection module, wherein the pretreatment module processes a soil sample to obtain a soil sample solution; the centrifugal system generates a centrifugal force to move the liquid reagent in the chip passage to the outer periphery; the microfluidic chip allows the soil sample solution and the leaching solvent to flow, mix, and leach inside it under the action of the centrifugal force generated by the centrifugal system to obtain a leachate; the photoelectric detection module detects the leachate and measures the content of organic matter in the soil sample solution; the microfluidic chip includes a passage layer and a cover plate layer provided above the passage layer; the passage layer includes a passage layer body and a plurality of passage branches provided on the passage layer body; the passage branch includes a second solvent injection port, a sample inlet, an extraction cell, a microchannel, a filtration cell, a detection cell, a waste liquid cell, and a second vent hole; the inlet of the extraction cell is connected to the second solvent injection port and the sample inlet respectively, the outlet of the extraction cell is connected to the inlet of the microchannel, the outlet of the microchannel is connected to the inlet of the filtration cell, the outlet of the filtration cell is connected to the inlet of the detection cell, the outlet of the detection cell is connected to the inlet of the waste liquid cell, the waste liquid cell communicates with the second vent hole, a plurality of heating columns are provided in the extraction cell, a microarray and a plurality of microspheres are provided in the filtration cell, the microspheres are located above the microarray, and a filter pad is provided at the outlet of the filtration cell; the cover plate layer is provided with a first mounting hole, a plurality of sample introduction holes, a plurality of first solvent injection ports, and a plurality of first vent holes; a second mounting hole corresponding to the position of the first mounting hole is opened in the center of the passage layer body; the number of the sample introduction holes, the first solvent injection ports, the first vent holes, and the passage branches is the same, and they are provided in one-to-one correspondence; the sample introduction hole is provided corresponding to the sample inlet; the first vent hole is provided corresponding to the second vent hole; the first solvent injection port is provided corresponding to the second solvent injection port. The apparatus is characterized by this.

2. The apparatus according to claim 1, wherein the cover plate layer is provided with a visible window, and the visible window includes a through hole opened in the cover plate layer and a light transmissive film attached to the through hole.

3. Below the passage layer, a bottom plate layer is provided. The device according to claim 1, characterized in that a third mounting hole is mounted in the center of the bottom plate layer.

4. The filtering pad is at least one layer, and the filtering pad is a combination of any one or more of a metal filter mesh, a filter cloth made of a non-metallic material, and a filter membrane. The device according to claim 1 is characterized by this.

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