Microfluidic water quality analysis device and analysis method

Abstract

The invention discloses a microfluidic water quality analysis device and analysis method, and belongs to the technical field of water quality detection analysis, the analysis device comprises n detection channels which are arranged in parallel and used for sample injection, n is greater than or equal to 3, each detection channel is provided with a front enrichment valve and a rear detection valve which are connected in series, the detection channels are connected with a detection platform, the detection platform is integrated with an optical detection module, an electrochemical detection module and a fluorescence detection module; the detection platform is connected with the calibration module, and the calibration module selects to inject calibration liquid in real time according to the deviation degree of a detection result of the detection platform on a sample; the water quality analysis device is provided with an anti-blocking module. The calibration liquid can be injected into the detection platform in real time according to the deviation degree of a sample detection result, a real-time calibration mechanism is implemented, and the reliability of field detection data is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water quality detection and analysis, in particular to a microfluidic water quality analysis device and analysis method. BACKGROUND

[0002] Water pollution has a significant impact on humans and ecosystems. The first step in implementing pollution control is to detect pollutants in water bodies. There are various methods for water quality detection, such as spectroscopy, chromatography, and electrochemical technology. However, traditional detection methods require large laboratory equipment and cannot meet the demand for real-time detection on site. Microfluidic devices can break through the limitations of traditional detection instruments and become efficient and convenient tools for water quality analysis.

[0003] For example, the Chinese patent document with publication number CN217638303U discloses a microfluidic water quality detection device, which includes a reaction pool, a heater, a microfluidic detection device, a weighing extraction device, and a driving pump device. The weighing extraction device is used to extract an appropriate amount of digestion reagent and water sample. The driving pump device is used to drive the digestion reagent and water sample to flow into the weighing extraction device, the reaction pool, and the microfluidic detection device in sequence. The heater is used to heat the reaction pool. The microfluidic detection device is provided with multiple microfluidic chips. The reaction pool and the multiple microfluidic chips in the microfluidic detection device are connected by pipelines.

[0004] Although the detection device in the patent document can detect multiple items in parallel for the same water sample, the detection speed is fast. However, the detection device has poor adaptability when facing high turbidity and complex matrix water environments, and the reliability of the on-site data detected is insufficient. SUMMARY

[0005] The present application aims to provide a microfluidic water quality analysis device and analysis method to solve the problem of poor adaptability of existing microfluidic water quality detection devices when facing high turbidity and complex matrix water environments, and insufficient reliability of on-site data detected.

[0006] To achieve the above-mentioned purpose, the present application provides a microfluidic water quality analysis device, which includes n detection channels for sample injection arranged in parallel, n≥3; each detection channel is provided 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 injection of calibration liquid in real time according to the deviation degree of the detection result of the sample by the detection platform; and the water quality analysis device is provided with an anti-blocking module.

[0007] Further, the pre-enrichment valve and the post-detection valve are both flexible sealing valves, the flexible sealing layer is arranged on the top of the flexible sealing valve, and the flexible sealing layer is arranged close to the piezoelectric driving piece.

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

[0009] Further, the piezoelectric driving piece is arranged in a spaced manner with the flexible sealing layer, and the spacing between the two is 0.3mm-0.8mm.

[0010] Further, the pre-enrichment valve and the post-detection valve are both flexible sealing valves, the flexible sealing layer is arranged on the top of the flexible sealing valve, and the flexible sealing layer is arranged close to the piezoelectric driving piece.

[0011] Further, the detection channel is provided with a pressure detection module, the pressure detection module is electrically connected with the piezoelectric driving piece, and the piezoelectric driving piece is controlled to operate.

[0012] Further, the detection channel is provided with a pressure detection module, the pressure detection module is electrically connected with the piezoelectric driving piece, and the piezoelectric driving piece is controlled to operate.

[0013] Further, the diameter of the bypass channel is greater than that of the detection channel.

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

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

[0016] S1, control the injection sample, select the parallel detection channel, enrich through the pre-enrichment valve, and input the detection platform through the post-detection valve;

[0017] S2, multi-modal detection sample to obtain detection results, and analyze the deviation error of the sample detection results through data comparison;

[0018] S3, judge whether the deviation error exceeds the specified value, if yes, start the calibration liquid channel to inject calibration liquid for re-detection, and if no, output the detection results.

[0019] Compared with the prior art, the technical scheme provided by the application has the following beneficial effects:

[0020] The microfluidic water quality analysis device of the present application, a plurality of detection channels are arranged in parallel and connected with a detection platform, the detection platform integrates optical detection module, electrochemical detection module and fluorescence detection module, which can detect multiple parameters of the sample synchronously, and has high detection efficiency and low sample consumption. The detection platform is connected with a calibration module, the calibration module can inject calibration liquid to the detection platform in real time according to the deviation of the sample detection result, and a real-time calibration mechanism is implemented to improve the reliability of the data of the on-site detection. The analysis device is also provided with an anti-blocking module, which can enhance the adaptability to high turbidity and complex matrix of the water body environment.

[0021] Obviously, the elements or features described in the above single embodiment can be used alone or in combination in other embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0022] In the drawings, the size and proportion do not represent the actual size and proportion of the product. The drawings are merely illustrative, and some unnecessary elements or features are omitted for the sake of clarity.

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

[0024] Figure 2 is a sectional structural schematic diagram of a flexible sealing valve body in an embodiment of the present application;

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

[0026] Figure 4 is an electrode / optical detection integrated layout in an embodiment of the present application;

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

[0028] BRIEF DESCRIPTION OF DRAWINGS

[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 driving piece; 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-blocking modules of the analysis device are distributedly arranged, some of the anti-blocking modules are arranged in combination with valve bodies of the pre-enrichment valve 120 and the post-detection valve 130, and some of the anti-blocking modules are arranged in combination with the detection channel 110.

[0038] In some embodiments, the anti-blocking modules are arranged in combination with 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, and each of the flexible sealing valves comprises a flexible sealing layer 150 located at the top of the flexible sealing valve. The flexible sealing layer 150 is arranged in close contact with a piezoelectric driving sheet 140 arranged outside the flexible sealing valve. The flexible sealing layer 150 functions to prevent leakage and ensure that the valve body is always sealed. The piezoelectric driving sheet 140 functions to prevent blockage.

[0039] The flexible sealing layer 150 functions as a valve to achieve close contact between the valve seat and the closing member (such as a gate plate, a butterfly plate or a plug) through elastic deformation, thereby achieving an almost zero-leakage effect in the closed state. The flexible sealing layer 150 deforms after being compressed, filling in the microscopic unevenness of the traditional metal sealing surface and adapting to the deformation caused by temperature or pressure fluctuations. The traditional hard sealing valve is prone to leakage at low pressure, while the flexible sealing valve can still maintain high sealing performance under low pressure conditions.

[0040] The piezoelectric driving sheet 140 mainly adopts a piezoelectric ceramic driving sheet, which is the core of the intelligentization of the valve. The piezoelectric ceramic driving sheet is located in close contact with the fluid control unit (valve core / valve seat) and realizes precise and high-speed flow regulation through voltage-deformation conversion. Specifically, in the present embodiment, the piezoelectric driving sheet 140 is arranged in spaced relation to the flexible sealing layer 150, and the distance between the piezoelectric driving sheet 140 and the flexible sealing layer 150 is 0.3mm-0.8mm, which can be selected from 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm and 0.8mm, and the distance between the piezoelectric driving sheet 140 and the flexible sealing layer 150 is preferably 0.5mm.

[0041] It should be noted that the flexible sealing layer 150 is made of a PDMS / graphene composite material, and has a thickness of 0.5mm-1mm and an elastic modulus of 0.1MPa-0.5MPa. Specifically, the thickness can be selected from 0.5mm, 0.55mm, 0.65mm, 0.75mm, 0.85mm, 0.95mm and 1mm, and the elastic modulus can be selected from 0.1MPa, 0.15MPa, 0.25MPa, 0.35MPa, 0.45MPa and 0.5MPa.

[0042] Further, the pre-enrichment valve 120 and the post-detection valve 130 are both provided with a valve cavity, and the outlet cone angle of the valve cavity is 55°-65°, preferably 60°. The outlet cone angle affects the self-cleaning ability of the valve. A larger angle helps to squeeze out the deposits when the valve is closed, keeps the sealing surface clean, and prevents the valve from being blocked. The inlet cone angle is 10°-20°, preferably 15°. The main function of the inlet cone angle is to guide the fluid to enter the valve cavity smoothly, reduce the flow resistance and energy loss at the inlet. The size of the inlet cone angle will affect the flow coefficient. A smaller inlet cone angle can provide a larger flow area, improve the passing capacity, and enhance the anti-blocking effect.

[0043] In some embodiments, the anti-blocking module can be arranged in combination with the detection channel 110. The detection channel 110 is provided with a pressure detection module, which is electrically connected with the piezoelectric driving sheet 140 to control the operation of the piezoelectric driving sheet 140. The pressure detection module can collect flow path pressure data in real time, and when the pressure change rate exceeds a threshold value, a valve vibration instruction is generated, and the piezoelectric driving sheet 140 vibrates the valve according to the vibration instruction.

[0044] Further, as shown in Figure 3 The detection channel 110 is connected with a bypass channel 160, and the detection channel 110 and the bypass channel 160 are both provided with a switching valve 300, which is electrically connected with the pressure detection module. When the pressure detection module detects that the pressure in the detection channel 110 exceeds a threshold value, if the pressure is not restored in time, the switching valve 300 switches the flow path to the bypass channel 160, and an audible and visual alarm device can also be added for audible and visual alarm. The diameter of the bypass channel 160 is greater than that of the detection channel 110, which is beneficial to timely dredge the flow path and prevent blockage. In addition, the position of the detection channel 110 is also provided with a self-cleaning module 400, which can self-clean the inside of the detection channel and improve the anti-blocking effect. The self-cleaning module 400 adopts an ultrasonic cleaning module.

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

[0046] An aspect of the present application also provides a microfluidic water quality analysis method, as shown in Figure 5 The method comprises the following steps:

[0047] S1, injecting a sample, selecting a parallel detection channel 110, and inputting the detection platform 200 through the pre-enrichment valve 120 and the post-detection valve 130;

[0048] S2, detecting the sample by multi-modal detection to obtain a detection result, and analyzing the deviation error of the sample detection result by data comparison;

[0049] S3, determine whether the deviation error exceeds a specified value, if it exceeds the specified value, start the calibration liquid channel to inject calibration liquid for re-detection; if it does not exceed the specified value, output the detection result.

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

[0051]

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

[0053] Dynamic adjustment strategy: when the flow resistance mutation is >20%, trigger the piezoelectric driving piece 140 high-frequency micro-vibration mode (amplitude ±5μm).

[0054] When the water quality analysis device is clogged, the pressure sensor alarms, and the piezoelectric driving piece 140 vibrates at high frequency (amplitude ±5μm), relieving the clogging state. If the clogging still persists in the piezoelectric driving piece 140 high-frequency vibration state, the switching valve 300 activates the standby flow path (bypass channel 160), and the reverse flushing flow is activated, and the ultrasonic cleaning module works together to discharge the clogging particles from the outlet with a 60° wide angle, and the device resumes work.

[0055] Example 1

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

[0057] Sample processing:

[0058] Channel 1: Inject 10mL water sample with syringe pump, and adsorb ammonium ions through enrichment valve;

[0059] Channel 2: 0.45μm filter membrane retains microplastics, and optical scanning is performed to determine the particle size distribution;

[0060] Self-adaptive anti-clogging:

[0061] When the pressure in channel 2 rises by 15%, the algorithm triggers the valve to vibrate at high frequency (0.1s pulse);

[0062] If the pressure is not recovered, switch to the standby flow path and sound an audible and visual alarm.

[0063] Calibration closed loop:

[0064] Ammonia nitrogen detection value deviation from standard curve 8.2%→ automatic injection of bromine bromophenol blue calibration solution→ secondary detection deviation reduced to 1.7%.

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

[0066] Example 2

[0067] Take the detection of industrial park wastewater as an example

[0068] Test conditions:

[0069] Water sample: wastewater from a chemical plant discharge port (containing trace sulfonamide antibiotics, high turbidity)

[0070] Detection parameters: antibiotics + turbidity + microplastics

[0071] Anti-clogging:

[0072] Pressure surge 18%→ trigger 40kHz high frequency vibration→ pressure returns to normal within 3 seconds Multi-modal detection:

[0073]

[0074] Calibration closed loop:

[0075] Microplastic count deviation 7.2%→ automatic start standard particle calibration→ deviation reduced to 1.8%.

[0076] Comparative example 1

[0077] Traditional single-valve microfluidic chip

[0078] Technical features:

[0079] Single straight-through valve (no taper design)

[0080] No adaptive control algorithm

[0081] Single-mode detection (only electrochemical)

[0082] Test conditions:

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

[0084] Results:

[0085] Index Comparative Example Embodiment of the Invention Plugging rate 100% (1 run) 0% (automatic switching bypass) Detection limit (mg / L) 0.01 0.008 Recovery time Manual disassembly and cleaning <3 seconds automatic recovery Chip size 50 x 30 mm 2 ]] 35 x 20 mm 2 ]]

[0086] Comparative example 2

[0087] Commercial multi-parameter water quality instrument

[0088] Technical features:

[0089] Split detection (need to replace kit) no micro-plastic detection function open flow path (no anti-blocking design)

[0090] Test conditions:

[0091] Water sample: 0.2 μm micro-plastic containing drinking water Test parameters: five parameters + ammonia nitrogen

[0092] Results:

[0093] Index Comparative Example Embodiment of the Invention Microplastic detection limit Not supported 0.1 μm Detection time 20 minutes (including kit replacement) 8 minutes (no manual intervention) Ammonia nitrogen detection limit 0.02 mg / L 0.008 mg / L pH detection error ±0.15 ±0.08 Sample consumption 50 mL / parameter 2 mL (full parameter parallel detection)

[0094] Comparative example 3

[0095] Straight-through valve vs tapered valve (anti-blocking experiment)

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

[0097] Flow rate: 1.2 mL / min

[0098] Result comparison:

[0099]

[0100] Performance comparison summary

[0101]

[0102] In the description of the present application, it should be noted that the terms "front", "back", "left", "right", "up", "down", "top", "bottom", "inside", "outside" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0103] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above-mentioned terms in the present application can be understood according to the specific circumstances.

[0104] The scope of the invention is limited only by the claims. Alternative structures for the structures disclosed herein can be readily recognized as possible alternative embodiments by those skilled in the art, and the embodiments disclosed herein can be combined to produce new embodiments, all of which are within the scope of the appended claims, as a result of the teachings of this invention.

Claims

1. A microfluidic water quality analysis device comprising n detection channels for sample injection arranged in parallel, n > 3; characterized in that, Each of the detection channels is provided with a pre-enrichment valve and a post-detection valve in series, the detection channels are 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 injection of calibration liquid in real time according to the deviation degree of the detection result of the sample by the detection platform; the water quality analysis device is provided with an anti-blocking module.

2. The microfluidic water quality analysis device of claim 1, wherein, The pre-enrichment valve and the post-detection valve are both flexible sealing valves, the flexible sealing valve comprises a flexible sealing layer, the flexible sealing layer is located at the top of the flexible sealing valve, and the flexible sealing layer is closely attached to a piezoelectric driving piece.

3. The microfluidic water quality analysis device of claim 2, wherein, The thickness of the flexible sealing layer is 0.5mm-1mm, and the elastic modulus is 0.1MPa-0.5MPa.

4. The microfluidic water quality analysis device of claim 2, wherein, The piezoelectric driving piece is arranged in a spaced manner with the flexible sealing layer, and the spacing therebetween is 0.3mm-0.8mm.

5. The microfluidic water quality analysis device of claim 1, wherein, The pre-enrichment valve and the post-detection valve are both provided with a valve cavity, the outlet cone angle of the valve cavity is 55°-65°, and the inlet cone angle is 10°-20°.

6. The microfluidic water quality analysis device of claim 2, wherein, The detection channel is provided with a pressure detection module, the pressure detection module is electrically connected with the piezoelectric driving piece, and the piezoelectric driving piece is controlled to operate.

7. The microfluidic water quality analysis device of claim 6, wherein, The detection channel is connected to a bypass channel, the detection channel and the bypass channel are both provided with a switching valve, and the switching valve is electrically connected with the pressure detection module.

8. The microfluidic water quality analysis device of claim 1, wherein, The diameter of the bypass channel is greater than that of the detection channel.

9. The microfluidic water quality analysis device of claim 1, wherein, The inner wall of the detection channel is coated with a titanium dioxide nano coating.

10. A microfluidic water quality analysis method, characterized by, The method comprises the following steps: S1, control injection of a sample, select parallel detection channels, enrich through a pre-enrichment valve, input a detection platform through a post-detection valve, and quantitatively input the detection platform; S2, detect the sample in multiple modes to obtain a detection result, analyze deviation error of the detection result of the sample through data comparison; S3, judge whether the deviation error exceeds a specified value, if yes, start injection of calibration liquid through a calibration liquid channel to re-detect, and if no, output the detection result.

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