Microfluidic chip and water quality detection system

Abstract

The present application relates to the technical field of water quality detection and analysis, and discloses a microfluidic chip and a water quality detection system. The microfluidic chip includes a core body, a sample flow channel is formed in the core body for injecting samples, a standard liquid flow channel is suitable for injecting standard liquid or reagents, a confluence flow channel is connected to the sample flow channel and the standard liquid flow channel, there is at least one reagent flow channel, and the reagent flow channel is connected to the confluence flow channel, and the reagent flow channel is suitable for injecting reagents; the confluence flow channel branches out a first branch connected to a metering channel, and a second branch connected to a detection channel. The aforementioned core body has a high degree of integration, and the sample, standard liquid and reagent are optionally combined and then converged to the metering channel or the detection channel through the confluence flow channel, and different reagents can be introduced through the reagent flow channel or the standard liquid flow channel to realize different types of water sample parameter detection, thereby realizing multiple parameter detection of samples on one core body.

Description

Technical Field

[0001] The present application relates to the technical field of water quality detection and analysis, and in particular to a microfluidic chip and a water quality detection system. Background Art

[0002] When conducting water quality testing, it is necessary to conduct multiple tests on the samples to be tested to determine various parameters of the samples. However, the existing water quality testing systems or devices have a low degree of integration. When testing various parameters, different tests need to be performed on the samples in different environments or equipment to obtain the corresponding results. This leads to disadvantages such as low water quality testing efficiency, large sample consumption, and high cost. Summary of the invention

[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the present application is to propose a microfluidic chip for improving the integration level of the microfluidic chip and thus improving the efficiency of water quality detection and reducing the cost.

[0004] The present application further proposes a water quality detection system comprising a microfluidic chip.

[0005] In the first aspect, the microfluidic chip according to the embodiment of the present application includes a core body, in which a sample flow channel, a standard liquid flow channel, a confluence flow channel, a reagent flow channel, a metering channel and a detection channel are formed, the sample flow channel is used to inject samples, there is at least one standard liquid flow channel, and it is arranged in parallel with the sample flow channel, the standard liquid flow channel is suitable for injecting standard liquid or reagent, the confluence flow channel is connected to the sample flow channel and the standard liquid flow channel, there is at least one reagent flow channel, and the reagent flow channel is connected to the confluence flow channel, and the reagent flow channel is suitable for injecting reagents; the confluence flow channel branches out into a first branch connected to the metering channel, and a second branch connected to the detection channel, the reagent flow channel, the sample flow channel and the standard liquid flow channel are all connected to the first branch, the other end of the metering channel is connected to the first peristaltic pump, and the other end of the detection channel is connected to the atmosphere, wherein the first branch is also connected to the second peristaltic pump and the digestion module in sequence, and the first branch and the second branch are selectively connected.

[0006] According to the microfluidic chip of the embodiment of the present application, by improving the degree of core integration, the sample, standard solution and reagent can be selected and combined to converge to the metering channel or the detection channel through the confluence flow channel, and different reagents can be introduced through the reagent flow channel or the standard solution flow channel to realize different types of water sample parameter detection, thereby realizing multiple parameter detection of water samples on one core.

[0007] According to a further embodiment of the present application, the microfluidic chip includes: a first plate body and a second plate body, the first plate body is bonded to the second plate body to define a sample flow channel, a standard liquid flow channel, a confluence flow channel, a reagent flow channel, a metering channel and a detection channel, the volume of the metering channel and the detection channel is 50ul~250ul, the length is 10mm~50mm, the width is 0.5mm~3mm, and the end connected to the confluence flow channel is provided with a chamfer.

[0008] According to a further embodiment of the present application, the reagent flow channel is connected to the metering channel and the detection channel at the center position of the metering channel and the detection channel, and the flow diameters of the sample flow channel, the standard liquid flow channel, the confluence flow channel, and the reagent flow channel are 0.5mm~1mm.

[0009] According to a further embodiment of the present application, a projection of at least part of the converging flow channels in the thickness direction of the core is U-shaped, and a closed section of the U-shape is higher than an open section of the U-shape.

[0010] According to a further embodiment of the present application, the reagent flow channel includes: a first reagent flow channel, a second reagent flow channel and a third reagent flow channel.

[0011] In some embodiments, the detection channel has a first detection area and a second detection area, the metering channel has a first metering area and a second metering area, and the first detection area, the second detection area, the first metering area and the second metering area are each correspondingly provided with at least one set of light sources and receivers.

[0012] According to a further embodiment of the present application, the core body also includes: an attached flow channel and a first transfer flow channel and a second transfer flow channel; the sample flow channel and the standard liquid flow channel are both connected to the attached flow channel, and the attached flow channel is connected to the converging flow channel through the first transfer flow channel and the second transfer flow channel.

[0013] Furthermore, the core is constructed as a piece of quartz material.

[0014] In the second aspect, the water quality detection system according to the embodiment of the present application includes: the microfluidic chip in any of the aforementioned embodiments, a first peristaltic pump, a second peristaltic pump, and a digestion module, the first peristaltic pump is connected to the metering channel; the second peristaltic pump is connected to the second branch.

[0015] According to a further embodiment of the present application, the water quality detection system also includes: a three-way valve, a first port of the three-way valve is connected to the second peristaltic pump, a second port is connected to the digestion module, and a third port is used to discharge waste liquid.

[0016] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0018] Figure 1 is a schematic diagram of a first plate structure of a core according to an embodiment of the present application;

[0019] Figure 2 is an exploded structural diagram of a core according to an embodiment of the present application;

[0020] Figure 3 is an exploded structural diagram of the core according to another angle of the embodiment of the present application;

[0021] Figure 4 is a top view of a core according to an embodiment of the present application;

[0022] Figure 5 According to the embodiment of the present application Figure 4 Schematic diagram of the cross-sectional structure corresponding to line AA in FIG.

[0023] Figure 6 is a simplified schematic diagram of the internal flow path of the core according to an embodiment of the present application;

[0024] Figure 7 It is a simplified flow chart of ammonia nitrogen detection according to an embodiment of the present application.

[0025] Reference numerals:

[0026] 100-core;

[0027] 110-first plate, 120-second plate;

[0028] 210-sample flow channel;

[0029] 220-standard liquid flow channel, 221-first standard liquid flow channel, 222-second standard liquid flow channel;

[0030] 230-converging flow channel, 231-first branch, 2311-first section branch, 2312-second section branch, 2313-second pump port, 232-second branch, 233-first converging flow channel, 234-second converging flow channel, 235-third converging flow channel, 236-closing section, 237-liquid inlet section, 238-liquid outlet section;

[0031] 240 - reagent flow channel, 241 - first reagent flow channel, 242 - second reagent flow channel, 243 - third reagent flow channel;

[0032] 250 - metering channel, 251 - first metering area, 252 - second metering area, 253 - first pump port, 254 - first chamfer;

[0033] 260 - detection channel, 261 - first detection area, 262 - second detection area, 263 - exhaust port;

[0034] 270 - additional flow channel, 271 - first transfer flow channel, 272 - second transfer flow channel;

[0035] 310-first peristaltic pump, 320-second peristaltic pump;

[0036] 400-digestion module;

[0037] 510 - first valve body, 520 - second valve body, 530 - third valve body, 540 - fourth valve body, 550 - fifth valve body, 560 - sixth valve body, 570 - seventh valve body, 580 - eighth valve body, 590 - ninth valve body;

[0038] 600-three-way valve, 610-first port, 620-second port, 630-third port. DETAILED DESCRIPTION

[0039] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0040] In the description of the embodiments of the present application, it needs to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0041] In the description of the embodiments of the present application, "first feature" and "second feature" may include one or more of the features.

[0042] In the description of the embodiments of the present application, “plurality” means two or more.

[0043] In the description of the embodiments of the present application, a first feature being “above” or “below” a second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact via another feature therebetween.

[0044] In the description of the embodiments of the present application, a first feature “above”, “above” and “on” a second feature includes the first feature being directly above and diagonally above the second feature, or simply means that the first feature is horizontally higher than the second feature.

[0045] First, some technical terms involved in this application are explained:

[0046] Total nitrogen is the total amount of various forms of inorganic and organic nitrogen in water. It includes nitrate ions (NO3 - ), nitrite ion (NO2 - ) and amino groups (NH4 + ) and organic nitrogen such as proteins, amino acids and organic amines, calculated in milligrams of nitrogen per liter of water. It is often used to indicate the degree of nutrient pollution in water bodies.

[0047] Total phosphorus refers to the total amount of all forms of phosphorus in water, including inorganic phosphorus and organic phosphorus. Total phosphorus is an important indicator in the water environment. The main sources of total phosphorus include domestic sewage, fertilizers, organophosphorus pesticides and phosphate builders used in detergents. Excessive phosphorus in water is one of the main causes of foul and smelly water, eutrophication of lakes and red tides in bays.

[0048] In the form of free ammonia (NH3) and ammonium ions (NH4 + ) is called ammonia nitrogen. Ammonia nitrogen is a nutrient in water bodies, which can cause eutrophication of water. It is the main oxygen-consuming pollutant in water bodies and is toxic to fish and some aquatic organisms.

[0049] Chemical Oxygen Demand (COD) is a chemical method to measure the amount of reducing substances in a water sample that need to be oxidized. It is the oxygen equivalent of substances (usually organic matter) that can be oxidized by strong oxidants in wastewater, effluent from wastewater treatment plants, and contaminated water.

[0050] Standard solution: also called standard solution, plays a vital role in the water quality analysis process. Its main functions include instrument calibration, method verification, quality control, result comparison, instrument performance monitoring, method standardization, etc. Figure 1-Figure 6 A microfluidic chip and a water quality detection system according to embodiments of the present application are described.

[0051] The microfluidic chip according to the embodiment of the present application includes a core body 100 arranged in the microfluidic chip. The core body 100 is the core component of the microfluidic chip to realize online monitoring of water quality and is used to realize water quality detection. A sample flow channel 210, a standard liquid flow channel 220, a confluence flow channel 230, a reagent flow channel 240, a metering channel 250 and a detection channel 260 are formed in the core body 100.

[0052] Next reference Figure 1 Provide specific instructions.

[0053] The sample flow channel 210 is used to inject samples.

[0054] Specifically, the sample is a water sample to be tested, and the sample is injected through the flow channel to perform tests on multiple parameters.

[0055] For example, total nitrogen testing is performed to obtain the total amount of various forms of inorganic and organic nitrogen in water; for example, total phosphorus testing is performed to obtain the total amount of all forms of phosphorus in water; for example, ammonia nitrogen testing is performed to obtain the amount of free ammonia (NH3) and ammonium ions (NH4 + ) in the water body; for example, chemical oxygen demand (COD) testing is performed to obtain the oxygen equivalent of substances (usually organic matter) in the sample that can be oxidized by strong oxidants.

[0056] The standard liquid flow channel 220 is suitable for injecting standard liquid or reagents. There are one or more standard liquid flow channels 220, which are arranged in parallel with the sample flow channel 210. When there is only one standard liquid flow channel 220, the standard liquid flow channel 220 is connected in parallel with the sample flow channel 210. When there are multiple standard liquid flow channels 220, each standard liquid flow channel 220 is connected in parallel with each other and in parallel with the sample flow channel 210.

[0057] The sample flow channel 210 and the standard solution flow channel 220 are connected in parallel to the confluence flow channel 230 .

[0058] In some cases, the standard liquid flow channel 220 is used to pass the standard liquid. In other cases, the standard liquid flow channel 220 can also be used to pass the reagent to achieve the water quality parameter detection of the sample. Therefore, the standard liquid flow channel 220 is arranged in parallel with the sample flow channel 210 to achieve the function of simultaneously inputting the sample and the standard liquid, or simultaneously inputting the sample and the reagent. Of course, the standard liquid flow channel 220 can also be reused to inject the standard liquid and the reagent in sequence, or inject the reagent and the standard liquid in sequence.

[0059] There is one or more reagent flow channels 240 , and the multiple reagent flow channels 240 are connected in parallel. Each reagent flow channel 240 converges into the confluence flow channel 230 , and the reagent flow channels 240 are connected to the confluence flow channels 230 . The reagent flow channels 240 are suitable for injecting reagents.

[0060] Specifically, the sample flow channel 210 and the standard liquid flow channel 220 input the sample and the standard liquid, or the sample and the reagent, into the confluence flow channel 230; the reagent flow channel 240 inputs the reagent into the confluence flow channel 230. It can be seen that the confluence flow channel 230 realizes the confluence of the sample and the standard liquid, or the sample and the reagent, or the sample, the standard liquid and the reagent, and after the confluence, the confluenced liquid is transported to the metering channel 250 or the detection channel 260.

[0061] The confluence channel 230 branches into a first branch 231 connected to the metering channel 250, and a second branch 232 connected to the detection channel 260. The reagent flow channel 240, the sample flow channel 210 and the standard liquid flow channel 220 are all connected to the first branch 231. The other end of the metering channel 250 is connected to the first peristaltic pump 310, and the other end of the detection channel 260 is connected to the atmosphere. The first branch 231 is also connected to the second peristaltic pump 320 and the digestion module 400 in sequence, and the first branch 231 and the second branch 232 are selectively connected.

[0062] Specifically, the first branch 231 can branch out a bypass pipe for connecting the second peristaltic pump 320 and the digestion module 400 in sequence, and the confluence channel 230 can realize different internal circulation modes according to the connectivity between the first branch 231 and the second branch 232, for example, a valve body is set between the first branch 231 and the second branch 232 to realize the opening and closing of the first branch 231 and the second branch 232.

[0063] In an exemplary case, the first branch 231 is not connected to the second branch 232 , and the reagent flow channel 240 , the sample flow channel 210 , and the standard solution flow channel 220 are converged into the metering channel 250 through the first branch 231 .

[0064] In another exemplary case, the first branch 231 is connected to the second branch 232 , and the reagent flow channel 240 , the sample flow channel 210 , and the standard liquid flow channel 220 are connected to the second branch 232 through the first branch 231 , and then converge in the detection channel 260 through the second branch 232 .

[0065] According to the microfluidic chip of the embodiment of the present application, by improving the integration level of the core body 100, the sample, standard solution and reagent can be optionally combined and converged to the metering channel 250 or the detection channel 260 through the confluence channel 230, and different reagents can be introduced through the reagent flow channel 240 or the standard solution flow channel 220 to realize different types of water sample parameter detection, thereby realizing multiple parameter detection of water samples on one core body 100.

[0066] In some embodiments, reference Figure 2-Figure 4 As shown below for understanding.

[0067] The core 100 is plate-shaped as a whole and includes a first plate 110 and a second plate 120, the first plate 110 and the second plate 120 are bonded, wherein the first plate 110 and the second plate 120 are provided with grooves on the planes for bonding, after the first plate 110 and the second plate 120 are bonded, the grooves of the two are spliced ​​and define a sample flow channel 210, a standard liquid flow channel 220, a confluence flow channel 230, a reagent flow channel 240, a metering channel 250 and a detection channel 260. The first plate 110 and the second plate 120 can be set to quartz glass material or PDMS, silicate glass, acrylic, etc.

[0068] In some examples, the thickness of the first plate 110 and the second plate 120 are both 3-5 mm, the volume of the metering channel 250 and the detection channel 260 is 50 ul to 250 ul, the length is 10 mm to 50 mm, and the width is 0.5 mm to 3 mm. The cavity is a long and narrow rectangular parallelepiped, with a length of 10-50 mm, and a width and height of 0.5-3 mm.

[0069] For example, if the thickness of the first plate body 110 and the second plate body 120 are both 3 mm, when the first plate body 110 and the second plate body 120 are bonded, a core body 100 with a thickness of 6 mm is formed. For another example, if the thickness of the first plate body 110 and the second plate body 120 are both 5 mm, when the first plate body 110 and the second plate body 120 are bonded, a core body 100 with a thickness of 10 mm is formed. For another example, if the thickness of the first plate body 110 and the second plate body 120 are both 4 mm, when the first plate body 110 and the second plate body 120 are bonded, a core body 100 with a thickness of 8 mm is formed.

[0070] For example, if the volume of the metering channel 250 and the detection channel 260 is 50ul, the length is 10mm, and the width is 0.5mm, less body fluid is input into the metering channel 250 and the detection channel 260 to complete the detection. For another example, if the volume of the metering channel 250 and the detection channel 260 is 250ul, the length is 50mm, and the width is 3mm, more body fluid is input into the metering channel 250 and the detection channel 260 to complete the detection. It can also be set to be 60ul, 15mm, and 1mm in width.

[0071] It can be understood that the metering channel 250 is used for metering, and during metering, an external light source is required to illuminate a local area to achieve the purpose of metering. Similarly, the detection channel 260 is based on an external light source to illuminate a local area to obtain absorbance. Therefore, the metering channel 250 and the detection channel 260 are constructed as narrow and long rectangular cavities, which can reduce the illumination area of ​​the light source for the metering channel 250 or the detection channel 260, thereby improving the accuracy of detection or measurement.

[0072] In some examples, the first branch 231 is connected to the center of the metering channel 250, and similarly, the second branch 232 is connected to the center of the detection channel 260, and the flow diameters of the sample flow channel 210, the standard liquid flow channel 220, the confluence flow channel 230, and the reagent flow channel 240 are 0.5mm~1mm.

[0073] Specifically, when the flow diameter of the sample flow channel 210, the standard liquid flow channel 220, the confluence flow channel 230, and the reagent flow channel 240 is 0.5 mm, the liquid in each flow channel is less. For another example, when the flow diameter of the sample flow channel 210, the standard liquid flow channel 220, the confluence flow channel 230, and the reagent flow channel 240 is 1 mm, the liquid in each flow channel is more. Alternatively, the flow diameter of the sample flow channel 210, the standard liquid flow channel 220, the confluence flow channel 230, and the reagent flow channel 240 is set to 0.8 mm.

[0074] It can be understood that by setting the first branch 231 at the center of the metering channel 250 and the second branch 232 at the center of the detection channel 260, the liquid will flow into the metering channel 250 and the detection channel 260 from the center, which can prevent bubbles generated by liquid flow from hanging on the inner wall of the metering channel 250 or the detection channel 260 during operation of the microfluidic chip.

[0075] Moreover, the core body 100 constructed based on the corresponding specific parameters has the characteristics of miniaturization and integration. The projected area of ​​the core body 100 in the thickness direction in this example is reduced to a rectangular structure of 72 mm by 62 mm, so as to integrate all functions of sampling, liquid preparation, metering, and detection on the miniaturized core body 100.

[0076] Furthermore, one end of the metering channel 250 communicating with the confluence channel 230 and one end of the detection channel 260 communicating with the confluence channel 230 are both provided with chamfers. Specifically, a first chamfer 254 is provided in the metering channel 250, and a second chamfer (not shown in the figure) is provided in the detection channel 260.

[0077] Combination Figure 2-Figure 5 As shown, the first chamfer 254 is described by taking the metering channel 250 as an example.

[0078] The first branch 231 in the converging flow channel 230 is connected to the metering channel 250. Here, the end of the metering channel 250 connected to the first branch 231 is defined as the first end. Figure 2-3 As shown, the metering channel 250 formed by the first plate 110 and the second plate 120 is a rectangular hollow structure as a whole, which is connected to the first branch 231 at the center of the first end, and the first end is configured with a plurality of first chamfers 254 arranged around the center of the first end, for example Figure 5 Two oppositely disposed first chamfers 254 are shown.

[0079] The second chamfer in the detection channel 260 is substantially consistent with the first chamfer 254 in the metering channel 250 and will not be described in detail herein.

[0080] It is understandable that the chamfered structure can guide the liquid in the metering channel 250 or the detection channel 260 to flow in the chamfered direction to avoid bubbles or liquid residues in the metering channel 250 or the detection channel 260 .

[0081] In order to better illustrate the flow channel in the core 100 of the embodiment of the present application, Figure 1 and Figure 6 Provide detailed explanation.

[0082] The core 100 is provided with a plurality of valve bodies, which control the flow of liquid inside the core 100 by controlling the opening and closing of the valve bodies. The valve bodies include a first valve body 510, a second valve body 520, a third valve body 530, a fourth valve body 540, a fifth valve body 550, a sixth valve body 560, a seventh valve body 570, an eighth valve body 580 and a ninth valve body 590. The ninth valve body 590 is used to connect the first branch 231 with the second branch 232.

[0083] It is also worth noting that one end of the metering channel 250 is connected to the first pump port 253, and the other end is connected to the first branch 231. Among them, the first pump port 253 is used to be externally connected to the first peristaltic pump 310, and the middle section of the first branch 231 is provided with a second pump port 2313, and the second pump port 2313 is used to be externally connected to the second peristaltic pump 320. The first branch 231 is divided into a first branch 2311 and a second branch 2312 by the second pump port 2313. The first branch 2311 is used to connect to the metering channel 250, and the middle section of the second branch 2312 is connected to the converging flow channel 230, and the outlet end is connected to the ninth valve body 590. In addition, one end of the detection channel 260 is connected to the second branch 232, and the other end is an exhaust port 263 (that is, the other end of the detection channel is connected to the atmosphere).

[0084] refer to Figure 1 and Figure 6 As shown, the reagent flow channel 240 includes a first reagent flow channel 241 , a second reagent flow channel 242 and a third reagent flow channel 243 . The three reagent flow channels 240 are respectively used to connect different reagents, and a valve body for controlling the opening and closing is provided between each reagent flow channel 240 and the confluence flow channel 230 .

[0085] Specifically, a sixth valve body 560 is provided between the first reagent flow channel 241 and the confluence flow channel 230, and two interfaces of the sixth valve body 560 are respectively connected to the first reagent flow channel 241 and the confluence flow channel 230, and the opening and closing between the first reagent flow channel 241 and the confluence flow channel 230 is controlled by the sixth valve body 560. A seventh valve body 570 is provided between the second reagent flow channel 242 and the confluence flow channel 230, and two interfaces of the seventh valve body 570 are respectively connected to the second reagent flow channel 242 and the confluence flow channel 230, and the opening and closing between the second reagent flow channel 242 and the confluence flow channel 230 is controlled by the seventh valve body 570. An eighth valve body 580 is provided between the third reagent flow channel 243 and the confluence flow channel 230, and two interfaces of the eighth valve body 580 are respectively connected to the third reagent flow channel 243 and the confluence flow channel 230, and the opening and closing between the third reagent flow channel 243 and the confluence flow channel 230 is controlled by the sixth valve body 560.

[0086] It is understandable that the three reagent flow channels 240 can be configured to achieve gating between different reagent flow channels 240 and the confluence flow channel 230, thereby allowing different reagents to pass into the metering channel 250 or the detection channel 260 according to different situations to achieve different parameter detection. The three reagent flow channels 240 are integrated into the same core 100 and the gating is achieved through the valve body, which helps to improve the integration of the core 100, thereby integrating multiple parameter detection functions on one core 100.

[0087] Furthermore, the core 100 further defines an attached flow channel 270 and a first transfer flow channel 271 and a second transfer flow channel 272 connected to the attached flow channel 270 , and the attached flow channel 270 is also connected to the sample flow channel 210 , the first standard liquid flow channel 221 and the second standard liquid flow channel 222 .

[0088] In order to better explain the first transfer channel 271 and the second transfer channel 272, Figure 1 The flow channels in the converging flow channel 230 shown in the figure that converge to the second branch 2312 are respectively defined as: the first converging flow channel 233, the second converging flow channel 234, and the third converging flow channel 235. One end of the first transfer flow channel 271 is connected to the attached flow channel 270, and the other end is directly connected to the second converging flow channel 234; one end of the second transfer flow channel 272 is connected to the attached flow channel 270, and the other end is directly connected to the third converging flow channel 235, and the second reagent flow channel 242 is connected to the second converging flow channel 234, and the third reagent flow channel 243 is connected to the third converging flow channel 235.

[0089] The standard liquid flow channel 220 is connected to the attached flow channel 270 through the first valve body 510, the first standard liquid flow channel 221 is connected to the attached flow channel 270 through the second valve body 520, the second standard liquid flow channel 222 is connected to the attached flow channel 270 through the third valve body 530, the attached flow channel 270 is connected to the first transfer flow channel 271 through the fourth valve body 540, the attached flow channel 270 is transferred to the second transfer flow channel 272 through the fifth valve body 550, the first reagent flow channel 241 is connected to the first confluence flow channel 233 through the sixth valve body 560, the second reagent flow channel 242 is connected to the second confluence flow channel 234 through the seventh valve body 570, and the third reagent flow channel 243 is connected to the third confluence flow channel 235 through the eighth valve body 580. Each valve body controls the passage between the two flow channels by opening and closing itself.

[0090] It can be understood that the standard liquid flow channel 220 and the sample flow channel 210 are connected to the corresponding confluence flow channel 230 through the auxiliary flow channel 270 and the first transfer flow channel 271 and the second transfer flow channel 272, respectively, so as to realize the reuse of the confluence flow channel 230 (the same confluence flow channel 230 is used to pass different liquids), thereby realizing the function of simultaneously inputting multiple reagents into the core body 100 for detection, so as to complete the detection of different parameters. Therefore, the reuse of the confluence flow channel 230 can not only improve the integration degree of the core body 100, but also realize the function of simultaneously inputting multiple types of reagents to complete the detection of different parameters.

[0091] Combining the above content, we can know that:

[0092] The sample enters the core body 100 from the sample flow channel 210, and enters the auxiliary flow channel 270 through the first valve body 510, and then enters the first transfer flow channel 271 through the fourth valve body 540. The liquid further enters the second confluence flow channel 234 from the first transfer flow channel 271, keeping the ninth valve body 590 closed, and the liquid flows into the metering channel 250 from the first branch 231; after the metering is completed, the ninth valve body 590 is opened to allow the liquid to flow into the detection channel 260 through the ninth valve body 590.

[0093] The standard liquid enters the core body 100 from the first standard liquid flow channel 221 or the second standard liquid flow channel 222, and then enters the first transfer flow channel 271 or the second transfer flow channel 272 from the fourth valve body 540 or the fifth valve body 550 through the auxiliary flow channel 270. The rest is basically the same as the sample flow method, and the process is not repeated here.

[0094] The reagent enters the core 100 from the first reagent flow channel 241, the second reagent flow channel 242, or the third reagent flow channel 243. Since the reagent flow channel 240 is directly connected to the confluence flow channel 230, the first reagent flow channel 241, the second reagent flow channel 242, and the third reagent flow channel 243 respectively converge into the first branch 231 from the first confluence flow channel 233, the second confluence flow channel 234, and the third confluence flow channel 235. The subsequent process is basically the same as the above two processes and will not be repeated here.

[0095] In some examples, the projection of the converging flow channel 230 in the thickness direction of the core 100 is U-shaped, and the closed section 236 of the U-shape is higher than the open section of the U-shape.

[0096] Continue to combine Figure 1 As shown in the figure, the first confluence channel 233, the second confluence channel 234, and the third confluence channel 235 are all U-shaped and arranged in sequence from the outside to the inside. The following is a detailed description taking the first confluence channel 233 as an example.

[0097] The U-shaped structure of the first converging flow channel 233 projected in the thickness direction of the core 100 includes two straight flow channels and one arcuate flow channel, the open ends of the two straight flow channels are respectively connected to the second branch 2312 and the first reagent flow channel 241, and the arcuate section is a closed section 236. For better explanation, the straight line section connected to the first reagent flow channel 241 is defined as a liquid inlet section 237, and the straight line section connected to the second branch 2312 is defined as a liquid outlet section 238.

[0098] It is understandable that when testing different parameters, various types of liquids enter the converging flow channel 230 from the liquid inlet section 237 and flow to the liquid outlet section 238 after passing through the closed section 236 (i.e., the arc-shaped portion). After the liquid flow is completed, since the detection channel 260 and the metering channel 250 are in a filled state, the liquid outlet section 238 has a higher hydraulic pressure than the liquid inlet section 237 directly connected to the detection channel 260 and the metering channel 250, thereby causing liquid reflux. The closed section 236 (i.e., the arc-shaped section) is constructed so that the projection in the thickness direction is higher than the two straight sections (i.e., the liquid inlet section 237 and the liquid outlet section 238), which can prevent the reflux of liquid caused by the pressure difference.

[0099] In order to detect different parameters of the liquid, the microfluidic chip also includes multiple light sources (not shown in the figure) and multiple receivers (not shown in the figure). The light sources and receivers are arranged in pairs on both sides of the thickness of the core 100, and at least one set of light sources and receivers are arranged corresponding to the metering channel 250 and the detection channel 260, and the light emission wavelengths of the multiple light sources are different.

[0100] The light source of the microfluidic chip can be a xenon lamp, a deuterium lamp or other light source that can emit a specific wavelength. The light source is connected to a microphotovoltaic cell, which can also be a photodiode, a spectrometer or other device. The light source irradiates the liquid and is received by a receiver to realize the corresponding detection function.

[0101] When the first branch 231 passes liquid into the metering channel 250 during metering, or when the second branch 232 passes liquid into the detection channel 260 during detection, the liquid will gradually fill the corresponding channel. Therefore, metering or detection can be performed at different filling levels based on the degree of liquid filling into the channel.

[0102] For example, the detection channel 260 has a first detection area 261 and a second detection area 262, the metering channel 250 has a first metering area 251 and a second metering area 252, and the first detection area 261, the second detection area 262, the first metering area 251 and the second metering area 252 are each correspondingly provided with at least one set of light sources and receivers.

[0103] The metering area on the side of the metering channel 250 away from the first branch 231 is the first metering area 251, and the side close to the first branch 231 is the second metering area 252. When the liquid is charged and filled to half the capacity of the metering channel 250, the liquid capacity in the second metering area 252 is 50ul, and the liquid in the second metering area 252 is metered based on the light sources and receivers on both sides of the first metering area 251. When the liquid fills the capacity of the metering channel 250, the liquid capacity in the metering channel 250 is 100ul when the light sources and receivers on both sides of the first metering area 251 perform metering.

[0104] Similarly, two detection areas are provided in the detection channel 260, namely the first detection area 261 and the second detection area 262. Each detection area is provided with a light source and a receiver, which are respectively located on both sides of the microfluidic chip and installed opposite to each other. Similarly, according to the fullness of the liquid in the detection channel 260, the light point of the light source corresponding to the first detection area 261 is located below the liquid level of 60ul, and the light point of the light source corresponding to the second detection area 262 is located below the liquid level of 150ul, which will not be repeated here.

[0105] Next, several detection situations are described with examples.

[0106] For example, when the sample to be tested is subjected to ammonia nitrogen detection, the first detection area 261 uses 230 nanometers of light to measure the absorbance of the water sample, and the second detection area 262 uses 275 nanometers of light to measure the absorbance of the water sample.

[0107] For another example, when the sample to be tested is tested for total nitrogen, the first detection area 261 uses 700 nanometer light to measure the absorbance of the water sample.

[0108] For another example, when the sample to be tested is subjected to a chemical oxygen demand (COD) test, the first detection area 261 uses 254 nanometer light to measure the absorbance of the water sample.

[0109] According to the water quality detection system of the embodiment of the present application, the microfluidic chip described in any one of the aforementioned embodiments and the first peristaltic pump 310, the second peristaltic pump 320 and the digestion module 400, the first peristaltic pump 310 is connected to the metering channel 250, and the second peristaltic pump 320 is connected to the second branch 232.

[0110] Specifically, a ninth valve body 590 is provided between the second peristaltic pump 320 and the second branch 232, and the ninth valve body 590 controls the on-off between the second peristaltic pump 320 and the second branch 232. Of course, it can also be set as follows: Figure 1 As shown, the second peristaltic pump 320 is connected to the middle section of the first branch 231 through the second pump port 2313, and then connected to the second branch 232 through the first branch 231, and a ninth valve body 590 is set between the first branch 231 and the second branch 232 to control the flow of the second peristaltic pump 320 and the second branch 232.

[0111] Furthermore, the system further comprises a three-way valve 600, a first port 610 of the three-way valve 600 is connected to the second peristaltic pump 320, a second port 620 is connected to the digestion module 400, and a third port 630 is used to discharge waste liquid. The digestion module 400 is used for heating and digestion treatment.

[0112] Exemplary, reference Figure 6 As shown, the second peristaltic pump 320 is connected to the first branch 231, and the first branch 231 and the second branch 232 are connected through the ninth valve body 590, and the opening and closing between the first branch 231 and the second branch 232 is controlled by the ninth valve body 590. Therefore, the second peristaltic pump 320 is connected to the ninth valve body 590 and the second branch 232 through the first branch 231. The second peristaltic pump 320 is connected to the first port 610 of the three-way valve 600, and the waste liquid is discharged to the third port 630 or the liquid is transported to the digestion module 400 through the driving action of the second peristaltic pump 320.

[0113] It is understandable that the three-way valve 600 and the second peristaltic pump 320 can realize the function of liquid delivery to the digestion module 400 or liquid delivery to the detection channel 260 or discharge of waste liquid, thereby realizing multiple different functions in the core body 100 structure, thereby improving the integration level of the core body 100.

[0114] Next, continue to combine Figure 1 and Figure 6 For understanding, taking the case of ammonia nitrogen detection as an example, the working condition of the detection system of the embodiment of the present application is explained.

[0115] Specifically, ammonia nitrogen detection uses salicylic acid spectrophotometry, which requires reducing the nitrate in the sample to nitrite under acidic conditions through a reducing agent, and then the nitrite reacts with salicylic acid under acidic conditions to generate a red azo dye. The color depth of the azo dye is proportional to the concentration of nitrite, and its absorbance is measured at a specific wavelength by a spectrophotometer. The maximum absorption wavelength of the dye is usually between 630-700 nanometers. Lambert-Beer's law can be used to determine the concentration of ammonia nitrogen in the water sample by measuring the absorbance at this wavelength.

[0116] refer to Figure 7 To understand and test, the following steps are included:

[0117] S1 . The sample to be tested connected to the sample flow channel 210 is pumped into the core 100 by the first peristaltic pump 310 .

[0118] Under the suction force of the first peristaltic pump 310, the sample to be tested passes through the first valve body 510 into the auxiliary flow channel 270, and the auxiliary flow channel 270 passes through the fifth valve body 550 into the first transfer flow channel 271, and then enters the third confluence flow channel 235 from the first transfer flow channel 271 to converge the liquid to the first branch 231, and finally flows into the metering channel 250 through the first branch 231 for metering.

[0119] S2. Push the sample to be detected in the metering channel into the digestion module 400 through the first peristaltic pump 310 .

[0120] After completing S1, the driving direction of the first peristaltic pump 310 is reversed so that the sample to be tested in the metering channel 250 is input into the first branch 231, the first port 610 and the second port 620 of the three-way valve 600 are kept in an open state, the third port 630 is closed, and then input into the digestion module 400 through the second peristaltic pump 320 and the first port 610 and the second port 620 of the three-way valve 600.

[0121] S3 . The reagent connected to the first reagent flow channel 241 is pumped into the core body 100 by the first peristaltic pump 310 .

[0122] Combination Figure 1 and Figure 6As shown, the driving direction of the first peristaltic pump 310 is reversed again to achieve the suction effect on the liquid, and the third reagent flow channel 243 is connected to the third confluence flow channel 235 through the eighth valve body 580, so the eighth valve body 580 can be switched to an open state to achieve the reuse of the third confluence flow channel 235, and the first reagent is input into the first branch 231 through the third confluence flow channel 235 and then sucked into the metering channel 250 for metering. Specifically, the first reagent is sulfuric acid and aminosulfonic acid amine solution.

[0123] S4. Push the first reagent in the metering channel into the digestion module 400 through the first peristaltic pump 310 .

[0124] The process in this step is basically the same as that in S2, where the sample to be detected is replaced with the first reagent, and after being mixed with the sample to be detected in the digestion module 400, it is heated to perform a reduction reaction, and then cooled after the reaction is completed.

[0125] S5 , pumping the second reagent externally connected to the first standard liquid flow channel 221 into the core 100 through the first peristaltic pump 310 .

[0126] The second reagent flows from the first standard liquid flow channel 221 into the auxiliary flow channel 270 , and the subsequent flow process of the second reagent is basically the same as S1 , replacing the sample to be detected with the second reagent.

[0127] S6. Push the first reagent in the metering channel into the digestion module 400 through the first peristaltic pump 310 .

[0128] This step is basically the same as S2, where the sample to be tested is replaced with the second reagent and input into the digestion module 400 to mix with other liquids. Specifically, the second reagent is a salicylic acid solution and a naphthalene ethylenediamine hydrochloride solution, and the salicylic acid solution and the naphthalene ethylenediamine hydrochloride solution are mixed with other solutions in the digestion module 400 for a period of time to form an azo dye solution.

[0129] S7 . Inject the azo dye solution into the detection channel 260 through the second peristaltic pump 320 .

[0130] The second peristaltic pump 320 draws the azo dye solution in the digestion module 400 into the first branch 231, while the first peristaltic pump 310 is closed and the detection channel 260 is opened for external air, so that the azo dye solution cannot enter the metering channel 250 and can only enter the detection channel 260 for absorbance testing. Finally, a standard curve is prepared using a nitrate nitrogen standard solution of known concentration, and the concentration of ammonia nitrogen in the water sample is determined by comparing the absorbance.

[0131] Next, other exemplary situations are briefly described in combination with the description of the previous example.

[0132] For example, the total phosphorus test uses ammonium molybdate spectrophotometry. Ammonium molybdate reacts with phosphate under acidic conditions to form a yellow phosphomolybdic acid complex, the concentration of which is proportional to the concentration of phosphate in the water sample. Under acidic conditions, phosphate reacts with ammonium molybdate to form a yellow phosphomolybdic acid complex, whose maximum absorption wavelength is usually around 420 nanometers. By measuring the absorbance at this wavelength, the phosphate content in the water sample can be quantitatively analyzed according to the Lambert-Beer law.

[0133] During the test, the sample to be tested is extracted by the first peristaltic pump 310, and is input into the metering channel 250 through the first valve body 510 and the fifth valve body 550 for metering, and then the measured water sample is injected into the detection channel 260 through the ninth valve body 590 by the first peristaltic pump 310. Then, the sulfuric acid solution is extracted by the first peristaltic pump 310, and is injected into the detection channel 260 after being metered through the metering channel 250.

[0134] Then, in the same way, the ascorbic acid solution and the ammonium molybdate solution are injected into the detection channel 260 successively, mixed thoroughly, and then left to stand for a certain period of time to complete the color development reaction. Finally, the absorbance of the solution after color development is measured under light of a wavelength of about 700 nanometers. Finally, a standard curve is prepared using a phosphate standard solution of known concentration, and the concentration of phosphate in the water sample is determined by comparing the absorbance.

[0135] For another example, the total nitrogen detection adopts ultraviolet spectrophotometry. Under acidic conditions, potassium persulfate is used as an oxidant to oxidize organic nitrogen, ammonia nitrogen and nitrite nitrogen in the water sample into nitrate. Nitrate has a strong absorption in the ultraviolet region of about 220 nanometers, and its absorbance is proportional to the concentration of nitrate. Lambert-Beer's law can be used to quantitatively analyze the total nitrogen content in the water sample by measuring the absorbance at this wavelength.

[0136] During the test, the sample to be tested is extracted by the first peristaltic pump 310, and enters the metering channel 250 for metering through the first valve body 510 and the fifth valve body 550. Then, the measured water sample is injected into the digestion module 400 through the first peristaltic pump 310. Then, the potassium persulfate solution and the sulfuric acid solution are respectively extracted by the first peristaltic pump 310, and are injected into the digestion module 400 after being metered through the metering channel 250, and are fully mixed and heated for a certain period of time for digestion and oxidation.

[0137] After oxidation and cooling to room temperature, the mixed solution is injected into the detection channel 260 by the second peristaltic pump 320, and the absorbance of the mixed solution is measured under light with a wavelength of 230 nanometers. A series of nitrate standard solutions of known concentrations are used to perform oxidation digestion and absorbance measurement according to the above steps. A standard curve is drawn with nitrate concentration as the horizontal coordinate and absorbance as the vertical coordinate. According to the absorbance of the sample, the corresponding nitrate concentration is found on the standard curve, which is the concentration of total nitrogen.

[0138] For another example, when performing a chemical oxygen demand (COD) test, the pretreated water sample is pumped into the detection channel 260 through the first peristaltic pump 310, and the absorbance of the water sample is measured under light with a wavelength of 254 nanometers. A standard solution with a known chemical oxygen demand test result (hereinafter referred to as COD value) is used to measure the UV254 absorbance of the standard solution and establish a calibration curve.

[0139] Specifically, UV254 refers to the ultraviolet absorbance at a wavelength of 254 nanometers. It is an indicator for measuring the content of organic matter in water, especially organic matter containing conjugated double bonds or aromatic rings. There is a certain correlation between UV254 and COD, so the COD value can be quickly estimated by measuring UV254.

[0140] The calibration curve relates the COD value to the UV254 absorbance. According to the UV254 absorbance of the water sample, the COD value is calculated by the calibration curve. During the process, the first standard liquid flow channel 221 and the second standard liquid flow channel 222 are respectively used to pass the standard liquid to obtain the corresponding standard result.

[0141] It can be understood that the detection system of the embodiment of the present application realizes the detection of multiple parameters of water quality by using a highly integrated microfluidic chip, thereby improving the efficiency of water quality detection, reducing the amount of reagents and standard solutions used, and reducing the cost of use.

[0142] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0143] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A microfluidic chip, characterized in that: include: A core body (100), wherein a sample flow channel (210), a standard liquid flow channel (220), a confluence flow channel (230), a reagent flow channel (240), a metering channel (250), and a detection channel (260) are formed in the core body (100); The sample flow channel (210) is used to inject a sample, the standard liquid flow channel (220) is at least one and is arranged in parallel with the sample flow channel (210), the standard liquid flow channel (220) is suitable for injecting a standard liquid or a reagent, the confluence flow channel (230) is connected to the sample flow channel (210) and the standard liquid flow channel (220), the reagent flow channel (240) is at least one and is connected to the confluence flow channel (230), and the reagent flow channel (240) is suitable for injecting a reagent; The confluence flow channel (230) branches into a first branch (231) connected to the metering channel (250), and a second branch (232) connected to the detection channel (260); the reagent flow channel (240), the sample flow channel (210), and the standard liquid flow channel (220) are all connected to the first branch (231); the other end of the metering channel (250) is connected to the first peristaltic pump (310), and the other end of the detection channel (260) is connected to the atmosphere; wherein the first branch (231) is also connected to the second peristaltic pump (320) and the digestion module (400) in sequence, and the first branch (231) and the second branch (232) are selectively connected; The projection of at least part of the converging flow channel (230) in the thickness direction of the core (100) is a U-shaped structure, the U-shaped structure comprising: two straight line segments and an arc segment for connecting the two straight line segments, wherein the arc segment is a closed segment (236), one end of the straight line segment away from the arc segment is configured as an open segment, and the closed segment (236) of the U-shaped structure is higher than the open segment; The microfluidic chip further comprises: an attached flow channel (270), a first transfer flow channel (271), and a second transfer flow channel (272); The sample flow channel (210) and the standard liquid flow channel (220) are both connected to the attached flow channel (270), and the attached flow channel (270) is connected to the converging flow channel (230) via the first transfer flow channel (271) and the second transfer flow channel (272).

2. The microfluidic chip according to claim 1, characterized in that: The microfluidic chip comprises: a first plate body (110) and a second plate body (120), wherein the first plate body (110) is bonded to the second plate body (120) to define the sample flow channel (210), the standard liquid flow channel (220), the confluence flow channel (230), the reagent flow channel (240), the metering channel (250) and the detection channel (260), wherein the volume of the metering channel (250) and the detection channel (260) is 50ul~250ul, the length is 10mm~50mm, the width is 0.5mm~3mm, and one end connected to the confluence flow channel (230) is provided with a chamfer.

3. The microfluidic chip according to claim 1, characterized in that: The reagent flow channel (240) is connected to the confluence flow channel (230), and the confluence flow channel (230) is connected to the metering channel (250) and the detection channel (260) at the center position of the metering channel (250) and the detection channel (260), and the diameters of the sample flow channel (210), the standard solution flow channel (220), the confluence flow channel (230), and the reagent flow channel (240) are 0.5 mm to 1 mm.

4. The microfluidic chip according to claim 1, characterized in that: The reagent flow channel (240) comprises: a first reagent flow channel (241), a second reagent flow channel (242) and a third reagent flow channel (243).

5. The microfluidic chip according to claim 4, characterized in that: The detection channel (260) has a first detection area (261) and a second detection area (262); the metering channel (250) has a first metering area (251) and a second metering area (252); the first detection area (261), the second detection area (262), the first metering area (251), and the second metering area (252) are each correspondingly provided with at least one set of light sources and receivers.

6. The microfluidic chip according to claim 5, characterized in that: The core (100) is constructed as a quartz material piece.

7. A water quality detection system, characterized in that: include: The microfluidic chip according to any one of claims 1 to 6; a first peristaltic pump (310), the first peristaltic pump (310) being connected to the metering channel (250); A second peristaltic pump (320) and a digestion module (400), wherein the second peristaltic pump (320) is connected to the second branch (232).

8. The water quality detection system according to claim 7, characterized in that: Also includes: A three-way valve (600), wherein the first port (610) of the three-way valve (600) is connected to the second peristaltic pump (320), the second port (620) is connected to the digestion module (400), and the third port (630) is used to discharge waste liquid.

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