Microfluidic water quality analysis device and analysis method

Abstract

The application discloses a kind of microfluidic water quality analysis device and analysis method, belongs to water quality detection and analysis technical field, analysis device, including the parallel arrangement of n for sample injection detection channel, n≥3, each described detection channel is provided with the pre-enrichment valve and post-detection valve in series, the detection channel is connected detection platform, the detection platform integrates optical detection module, electrochemical detection module and fluorescence detection module;The detection platform is connected calibration module, and the calibration module is injected with calibration liquid in real time according to the deviation degree of the detection result of sample by detection platform;The water quality analysis device is provided with anti-blocking module.The application can inject calibration liquid in real time according to the deviation degree of sample detection result to detection platform, implement real-time calibration mechanism, improve the reliability of data of on-site detection.

Description

Technical Field

[0001] This invention relates to the field of water quality testing and analysis technology, and more specifically, to a microfluidic water quality analysis device and analysis method. Background Technology

[0002] Water pollution has a significant impact on humans and ecosystems, and the first step in pollution control is to detect pollutants in water bodies. Currently, there are various methods for water quality testing, such as spectroscopic methods, chromatographic methods, and electrochemical techniques. However, traditional testing methods rely on large laboratory equipment, making it difficult to meet the needs of real-time on-site testing. Microfluidic devices can overcome the limitations of traditional testing instruments, becoming a highly efficient and convenient tool for water quality analysis.

[0003] For example, Chinese patent document CN217638303U discloses a microfluidic water quality testing device, including: a reaction tank, a heater, a microfluidic detection device, a weighing and extraction device, and a driving pump device; the weighing and extraction device is used to extract appropriate amounts of digestion reagent and water sample respectively, the driving pump device is used to drive the digestion reagent and water sample to flow sequentially into the weighing and extraction device, the reaction tank, and the microfluidic detection device, the heater is used to heat the reaction tank, and the microfluidic detection device is provided with multiple microfluidic chips, and the reaction tank and the multiple microfluidic chips in the microfluidic detection device are respectively connected through pipelines.

[0004] Although the testing device in this patent document can perform multiple tests on the same water sample in parallel and has a fast testing speed, it is not very adaptable to water environments with high turbidity and complex matrices, and the reliability of the on-site test data is insufficient. Summary of the Invention

[0005] The purpose of this invention is to provide a microfluidic water quality analysis device and method, which solves the problems of poor adaptability of existing microfluidic water quality detection equipment when facing water environments with high turbidity and complex matrices, and insufficient reliability of on-site detection data.

[0006] To achieve the above objectives, the present invention provides a microfluidic water quality analysis device, comprising n parallel detection channels for sample injection, n≥3; each detection channel is equipped with a pre-enrichment valve and a post-detection valve connected in series, the detection channel is connected to a detection platform, the detection platform integrates an optical detection module, an electrochemical detection module and a fluorescence detection module; the detection platform is connected to a calibration module, the calibration module selects the injection calibration solution in real time according to the deviation of the detection results of the detection platform on the sample; the water quality analysis device is equipped with an anti-clogging module.

[0007] Furthermore, both the pre-enrichment valve and the post-detection valve are flexible sealing valves. The flexible sealing valve includes a flexible sealing layer, which is located on top of the flexible sealing valve and is closely attached to the piezoelectric drive plate.

[0008] Furthermore, the thickness of the flexible sealing layer is 0.5 mm to 1 mm, and the elastic modulus is 0.1 MPa to 0.5 MPa.

[0009] Furthermore, the piezoelectric drive sheet and the flexible sealing layer are spaced apart, with a spacing of 0.3mm to 0.8mm.

[0010] Furthermore, both the pre-enrichment valve and the post-detection valve are provided with valve chambers, the outlet cone angle of which is 55° to 65° and the inlet cone angle is 10° to 20°.

[0011] Furthermore, the detection channel is equipped with a pressure detection module, which is electrically connected to the piezoelectric drive plate and controls the operation of the piezoelectric drive plate.

[0012] Furthermore, the detection channel is connected to a bypass channel, and both the detection channel and the bypass channel are equipped with a switching valve, which is electrically connected to the pressure detection module.

[0013] Furthermore, the diameter of the bypass channel is larger than the diameter of the detection channel.

[0014] Furthermore, the inner wall of the detection channel is coated with a titanium dioxide nano-coating.

[0015] This invention also provides a microfluidic water quality analysis method, comprising the following steps:

[0016] S1. Control the injected sample, select the parallel detection channel, enrich it through the pre-enrichment valve, and quantitatively input it into the detection platform through the post-detection valve;

[0017] S2. Multimodal detection of samples yields detection results, and the deviation error of the sample detection results is analyzed by data comparison.

[0018] S3. Determine whether the deviation error exceeds the specified value. If it exceeds the specified value, start the calibration fluid channel to inject calibration fluid and re-detect; if it does not exceed the specified value, output the detection result.

[0019] Compared with existing known technologies, the technical solution provided by this invention has the following beneficial effects:

[0020] This invention discloses a microfluidic water quality analysis device with multiple detection channels arranged in parallel and connected to a detection platform. The detection platform integrates an optical detection module, an electrochemical detection module, and a fluorescence detection module, enabling simultaneous detection of multiple parameters of a sample with high efficiency and low sample consumption. The detection platform is connected to a calibration module, which can inject calibration solution into the detection platform in real time based on the deviation of the sample detection results, implementing a real-time calibration mechanism to improve the reliability of on-site detection data. The analysis device also includes an anti-clogging module to enhance its adaptability to water environments with high turbidity and complex matrices.

[0021] It is obvious that the elements or features described in the above individual embodiments can be used alone or in combination in other embodiments. Attached Figure Description

[0022] The dimensions and scales in the accompanying drawings do not represent the dimensions and scales of the actual product. The drawings are for illustrative purposes only, and some non-essential elements or features have been omitted for clarity.

[0023] Figure 1 This is a schematic diagram of the microfluidic water quality analysis device in an embodiment of the present invention;

[0024] Figure 2 This is a cross-sectional view of the flexible sealing valve body in an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the detection channel and bypass channel in an embodiment of the present invention;

[0026] Figure 4 This is the electrode / optical detection integrated layout in this embodiment of the invention;

[0027] Figure 5 This is a flowchart illustrating the analysis method in an embodiment of the present invention.

[0028] Explanation of reference numerals in the attached figures

[0029] 100. Substrate; 110. Detection channel; 120. Pre-enrichment valve; 130. Post-detection valve; 131. Optical detection unit; 132. Electrochemical detection unit; 133. Fluorescence detection unit; 140. Piezoelectric drive sheet; 150. Flexible sealing layer; 160. Bypass channel;

[0030] 200. Detection platform; 210. Detection cavity substrate; 220. Optical detection module; 230. Counter electrode; 240. Reference electrode; 250. Working electrode; 260. Fluorescence detection module; 270. Microplastic detection laser;

[0031] 300. Switching valve;

[0032] 400. Self-cleaning module. Detailed Implementation

[0033] The present invention will now be described in detail with reference to the accompanying drawings. The embodiments described herein are merely preferred embodiments of the invention; those skilled in the art can conceive of other ways to implement the invention based on these preferred embodiments, and such other ways also fall within the scope of the invention.

[0034] Reference Figures 1-4 This embodiment provides a microfluidic water quality analysis device, including three parallel detection channels 110 for sample injection, which are mounted on a substrate 100. Each detection channel 110 is equipped with a pre-enrichment valve 120 and a post-detection valve 130 connected in series. The pre-enrichment valve 120 is used to enrich the sample, and the post-detection valve 130 is used to detect and quantify the sample. The detection channels 110 are connected to a detection platform 200, which integrates an optical detection module, an electrochemical detection module, and a fluorescence detection module. By having multiple detection channels 110 running in parallel and connected to the detection platform 200, the detection platform 200 can simultaneously detect multiple parameters, resulting in high detection efficiency and low sample consumption.

[0035] Each post-detection valve 130 is equipped with a different detection unit, such as an optical detection unit 131, an electrochemical detection unit 132, and a fluorescence detection unit 133, which are electrically connected to the optical detection module, electrochemical detection module, and fluorescence detection module 260 on the detection platform 200, respectively. The detection platform 200 is connected to a calibration module, which selects the injection of calibration solution in real time based on the deviation of the detection platform's test results for the sample, implementing a real-time calibration mechanism to improve the reliability of on-site test data. The water quality analysis device is equipped with an anti-clogging module, which enhances its adaptability to water environments with high turbidity and complex matrices.

[0036] It should be noted that the number of parallel detection channels 110 is no less than 3, and can be expanded to 8 according to actual working needs. The optical detection module 220 mainly integrates laser scattering and microscopic imaging technology units, which can detect turbidity, color, and microplastic parameters in the sample. Among them, microplastic parameters are mainly detected by microplastic detection laser 270. The electrochemical module mainly integrates a three-electrode array, including a working electrode 250, a counter electrode 230, and a reference electrode 240, which can detect ammonia nitrogen, pH value, and dissolved oxygen parameters in the sample. The fluorescence detection module 260 mainly integrates ultraviolet excitation and photon counter technology units, which can detect antibiotic parameters. It should be noted that the optical detection module 220, the electrochemical module, and the microplastic detection laser 270 are all mounted on the detection cavity substrate 210.

[0037] The anti-clogging modules of the analysis device are arranged in a distributed manner. Some anti-clogging modules are combined with the valve bodies of the pre-enrichment valve 120 and the post-detection valve 130, while some anti-clogging modules are combined with the detection channel 110.

[0038] In some embodiments, the anti-clogging module is integrated with the valve bodies of the pre-enrichment valve 120 and the post-detection valve 130. Both the pre-enrichment valve 120 and the post-detection valve 130 are flexible sealing valves, each including a flexible sealing layer 150 located at the top. The flexible sealing layer 150 is disposed in close contact with the piezoelectric actuator 140, which is located outside the flexible sealing valve. The flexible sealing layer 150 serves to prevent leakage, ensuring the valve body remains sealed. The piezoelectric actuator 140 serves to prevent clogging.

[0039] The flexible sealing layer 150, acting as a valve, achieves a tight fit between the valve seat and the closing element (such as a gate, butterfly plate, or plug) through elastic deformation, thus achieving near-zero leakage in the closed state. The flexible sealing layer 150 deforms under pressure, filling microscopic unevenness in traditional metal sealing surfaces and adapting to deformation caused by temperature or pressure fluctuations. While traditional hard-seal valves are prone to leakage under low pressure, flexible-seal valves maintain high sealing performance even under low-pressure conditions.

[0040] The piezoelectric actuator 140 mainly uses a piezoelectric ceramic actuator, which is the core of valve intelligence. Its position is close to the fluid control unit (valve core / seat), and it achieves precise and high-speed flow regulation through voltage-deformation conversion. Specifically, in this embodiment, the piezoelectric actuator 140 and the flexible sealing layer 150 are spaced apart, with a spacing of 0.3mm to 0.8mm. Selectable spacing options include 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, and 0.8mm, with 0.5mm being the preferred spacing.

[0041] It should be noted that the flexible sealing layer 150 is made of PDMS / graphene composite material, with a thickness of 0.5mm to 1mm and an elastic modulus of 0.1MPa to 0.5MPa. The selectable thicknesses are 0.5mm, 0.55mm, 0.65mm, 0.75mm, 0.85mm, 0.95mm, and 1mm, and the selectable elastic moduli are 0.1MPa, 0.15MPa, 0.25MPa, 0.35MPa, 0.45MPa, and 0.5MPa.

[0042] Furthermore, both the pre-positioned enrichment valve 120 and the post-positioned detection valve 130 have internal valve chambers. The outlet cone angle of these chambers is 55°–65°, preferably 60°. The outlet cone angle affects the valve's self-cleaning ability; a larger angle helps to dislodge deposits when the valve is closed, keeping the sealing surface clean and preventing valve blockage. The inlet cone angle is 10°–20°, preferably 15°. The main function of the inlet cone angle is to guide the fluid smoothly into the valve chamber, reducing flow resistance and energy loss at the inlet. The size of the inlet cone angle affects the flow coefficient; a smaller inlet cone angle provides a larger flow area, improving throughput and enhancing anti-clogging effects.

[0043] In some embodiments, the anti-clogging module can be integrated with the detection channel 110. The detection channel 110 is equipped with a pressure detection module, which is electrically connected to the piezoelectric actuator 140 and controls the operation of the piezoelectric actuator 140. The pressure detection module can collect flow path pressure data in real time. When the pressure change rate exceeds a threshold, it generates a valve vibration command, and the piezoelectric actuator 140 causes the valve to vibrate according to the vibration command.

[0044] Furthermore, such as Figure 3 As shown, the detection channel 110 is connected to a bypass channel 160. Both the detection channel 110 and the bypass channel 160 are equipped with a switching valve 300, which is electrically connected to the pressure detection module. When the pressure detection module detects that the pressure in the detection channel 110 exceeds the threshold, if the pressure does not recover in time, the switching valve 300 switches the flow path to the bypass channel 160. An audible and visual alarm device can also be added for this purpose. The diameter of the bypass channel 160 is larger than that of the detection channel 110, which facilitates timely unblocking of the flow path and prevents blockage. Furthermore, a self-cleaning module 400 is also installed in the detection channel 110, which can self-clean the interior of the detection channel, improving the anti-blocking effect. The self-cleaning module 400 uses an ultrasonic cleaning module.

[0045] In some embodiments, the inner wall of the detection channel is coated with a titanium dioxide nano-coating with a thickness of 200 nm to 500 nm, and the titanium dioxide nano-coating has a self-cleaning function.

[0046] One aspect of this application also provides a microfluidic water quality analysis method, such as... Figure 5 As shown, it includes the following steps:

[0047] S1. Inject the sample, select the parallel detection channel 110, and quantitatively input it into the detection platform 200 through the pre-enrichment valve 120 and the post-detection valve 130.

[0048] S2. Multimodal detection of samples yields detection results, and the deviation error of the sample detection results is analyzed by data comparison.

[0049] S3. Determine whether the deviation error exceeds the specified value. If it exceeds the specified value, start the calibration fluid channel to inject calibration fluid and re-detect; if it does not exceed the specified value, output the detection result.

[0050] It should be noted that in the above method steps, the flow path pressure data is collected in real time through a pressure detection module. When the pressure change rate exceeds a threshold, a valve vibration command is generated. The pressure detection module includes a pressure sensor with a sampling rate of 100Hz. Real-time pressure monitoring relies on an adaptive valve control algorithm to establish a valve opening-flow-pressure relationship model.

[0051]

[0052] Where Q represents flow rate, K represents flow path coefficient, ΔP represents pressure difference, and A v The valve orifice area is represented by μ / ρ, and the fluid viscosity / density is represented by μ / ρ. This formula is used to calculate the flow rate (Q) of a fluid through a specific channel (such as a pipe, valve, orifice). Its core is based on the pressure difference (ΔP) and the valve orifice area (A). v By combining parameters such as fluid properties and resistance factors, the volume or mass of fluid flowing per unit time can be obtained.

[0053] Dynamic adjustment strategy: When the flow resistance changes by more than 20%, the high-frequency micro-vibration mode (amplitude ±5μm) of the piezoelectric drive plate 140 is triggered.

[0054] When the water quality analyzer becomes clogged, the pressure sensor alarms, and the piezoelectric actuator 140 vibrates at high frequency (amplitude ±5μm) to alleviate the clogging. If the clogging persists despite the high-frequency vibration of the piezoelectric actuator 140, the switching valve 300 activates the backup flow path (bypass channel 160), and the reverse flushing flow is activated. The ultrasonic cleaning module works in conjunction to discharge the clogging particles from the 60° wide outlet cone, and the device resumes operation.

[0055] Example 1

[0056] Taking simultaneous detection of ammonia nitrogen and microplastics as an example

[0057] Sample processing:

[0058] Channel 1: 10 mL of water sample is injected by the syringe pump, and ammonium ions are adsorbed by the enrichment valve;

[0059] Channel 2: 0.45μm filter membrane traps microplastics; optical scanning particle size distribution.

[0060] Adaptive anti-blocking:

[0061] A sudden 15% pressure surge was detected in channel 2, triggering the algorithm to activate high-frequency valve vibration (0.1s pulse).

[0062] If the pressure does not recover, switch to the backup flow path and trigger an audible and visual alarm.

[0063] Calibration closed loop:

[0064] The ammonia nitrogen detection value deviated from the standard curve by 8.2% → bromothymol blue calibration solution was automatically injected → the deviation of the second detection was reduced to 1.7%.

[0065] It should be noted that both Channel 1 and Channel 2 refer to detection channel 110.

[0066] Example 2

[0067] Taking industrial park wastewater testing as an example

[0068] Test conditions:

[0069] Water sample: Wastewater from a chemical plant's discharge outlet (containing trace amounts of sulfonamide antibiotics, high turbidity)

[0070] Detection parameters: antibiotics + turbidity + microplastics

[0071] Anti-clogging:

[0072] A sudden 18% increase in pressure triggers a 40kHz high-frequency vibration, and the pressure returns to normal within 3 seconds. (Multimodal detection)

[0073]

[0074] Calibration closed loop:

[0075] Microplastic count deviation 7.2% → Automatic standard particle calibration initiated → Deviation reduced to 1.8%.

[0076] Comparative Example 1

[0077] Traditional single-valve microfluidic chips

[0078] Technical features:

[0079] Single straight-through valve (non-tapered design)

[0080] No adaptive control algorithm

[0081] Single-mode detection (electrochemical only)

[0082] Test conditions:

[0083] Water sample: Wastewater containing 100μm quartz sand (500 NTU) Detection parameters: Ammonia nitrogen

[0084] result:

[0085] Congestion rate 100% (1 run) 0% (Automatic bypass switching) Detection limit (mg / L) 0.01 0.008 Recovery time Manual disassembly and cleaning required Automatic recovery in 3 seconds Chip size <![CDATA[50×30mm 2 ]]> <![CDATA[35×20mm 2 ]]>

[0086] Comparative Example 2

[0087] Commercial multi-parameter water quality meter

[0088] Technical features:

[0089] Split-type detection (requires reagent kit replacement), no microplastic detection function, open flow path (no anti-clogging design).

[0090] Test conditions:

[0091] Water sample: Drinking water containing 0.2μm microplastics. Detection parameters: Five parameters + ammonia nitrogen.

[0092] result:

[0093] Microplastic detection limit Not supported 0.1μm Detection time 20 minutes (including reagent kit replacement) 8 minutes (no human intervention required) Ammonia nitrogen detection limit 0.02 mg / L 0.008 mg / L pH value detection error ±0.15 ±0.08 Sample consumption 50mL / parameter 2 mL (parallel detection with all parameters)

[0094] Comparative Example 3

[0095] Straight-through valve vs. tapered valve (anti-clogging test)

[0096] Test conditions: Blockage material: 100μm quartz sand

[0097] Flow rate: 1.2 mL / min

[0098] Result comparison:

[0099]

[0100] Performance Comparison Summary

[0101]

[0102] In the description of this invention, it should be noted that the terms "front," "rear," "left," "right," "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0103] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0104] The scope of protection of this invention is defined only by the claims. Thanks to the teachings of this invention, those skilled in the art will readily recognize that alternative structures to the structures disclosed herein can be used as feasible alternative implementations, and that the implementations disclosed herein can be combined to produce new implementations, which also fall within the scope of the appended claims.

Claims

1. A microfluidic water quality analysis device, comprising n parallel detection channels for sample injection, n≥3; characterized in that, Each detection channel is equipped with a pre-enrichment valve and a post-detection valve connected in series. The detection channel is connected to a detection platform, which integrates an optical detection module, an electrochemical detection module, and a fluorescence detection module. The detection platform is connected to a calibration module, which selects the injection of calibration solution in real time based on the deviation of the detection platform's test results for the sample. The water quality analysis device is equipped with an anti-clogging module. The anti-clogging module is arranged in a distributed manner, with some modules integrated with the valve bodies of the pre-enrichment valve and the post-detection valve, and some modules integrated with the detection channels. Both the pre-enrichment valve and the post-detection valve are flexible sealing valves. The sealing valve includes a flexible sealing layer located at the top of the valve and closely attached to the piezoelectric actuator. Both the pre-enrichment valve and the post-detection valve have internal valve chambers with outlet cone angles of 55°~65° and inlet cone angles of 10°~20°. The detection channel is equipped with a pressure detection module electrically connected to the piezoelectric actuator to control its operation. The detection channel is connected to a bypass channel, and both the detection channel and the bypass channel are equipped with switching valves electrically connected to the pressure detection module. The diameter of the bypass channel is larger than the diameter of the detection channel.

2. The microfluidic water quality analysis device according to claim 1, characterized in that, The thickness of the flexible sealing layer is 0.5mm~1mm, and the elastic modulus is 0.1MPa~0.5MPa.

3. The microfluidic water quality analysis device according to claim 1, characterized in that, The piezoelectric drive sheet and the flexible sealing layer are spaced apart, with a spacing of 0.3mm to 0.8mm.

4. The microfluidic water quality analysis device according to claim 1, characterized in that, The inner wall of the detection channel is coated with a titanium dioxide nano-coating.

5. A microfluidic water quality analysis method, employing the microfluidic water quality analysis device according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Control the injected sample, select the parallel detection channel, enrich it through the pre-enrichment valve, and quantitatively input it into the detection platform through the post-detection valve; S2. Multimodal detection of samples yields detection results, and the deviation error of the sample detection results is analyzed by data comparison. S3. Determine whether the deviation error exceeds the specified value. If it exceeds the specified value, start the calibration fluid channel to inject calibration fluid and re-detect; if it does not exceed the specified value, output the detection result.

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