Online monitoring method for orthophosphate concentration, microfluidic chip assembly and equipment

Abstract

The embodiment of the invention provides an on-line monitoring method for orthophosphate concentration, a micro-fluidic chip assembly and equipment, and the method comprises the following steps: a first chip mixes a water sample to be detected and a detection reagent to obtain a first mixed solution; the first chip determines a first absorbance value of the first mixed solution, determines a first concentration of orthophosphate in the to-be-detected water sample based on the first absorbance value, and transmits the first mixed solution to a second chip when the first concentration is less than or equal to a first threshold value; the second chip is used for extracting a first product in the first mixed solution to obtain a second mixed solution; and the second chip determines a second absorbance value of the second mixed solution, and determines a second concentration of orthophosphate in the to-be-detected water sample based on the second absorbance value. According to the embodiment of the invention, the accuracy of determining the concentration of the orthophosphate in the water sample to be detected is improved, and the application range of the online monitoring method for the concentration of the orthophosphate is expanded.

Description

Technical Field

[0001] The present invention relates to the technical field of water quality monitoring, and particularly to an on-line monitoring method, a microfluidic chip assembly and a device for the concentration of orthophosphate. Background Art

[0003] Currently, the vanadium molybdate yellow spectrophotometry or the molybdenum blue spectrophotometry is usually adopted to detect the concentration of orthophosphate in water sources. Specifically, in the vanadium molybdate yellow spectrophotometry, in an acidic medium, orthophosphate in the water source reacts with ammonium molybdate and ammonium metavanadate to form yellow phosphovanadomolybdic acid, and the absorbance of the phosphovanadomolybdic acid is proportional to the content of orthophosphate in the water source. Based on the absorbance of the phosphovanadomolybdic acid, the content of orthophosphate in the water source can be determined; in the molybdenum blue spectrophotometry, in an acidic medium, orthophosphate in the water source reacts with ammonium molybdate to form phosphomolybdic heteropolyacid, and the phosphomolybdic heteropolyacid can be reduced by ascorbic acid to form a blue complex. The absorbance of the blue complex is proportional to the content of orthophosphate in the water source. Based on the absorbance of the blue complex, the content of orthophosphate in the water source can be determined.

[0004] However, the vanadium molybdate yellow spectrophotometry is only applicable to the detection of the concentration of orthophosphate in water sources with a relatively high concentration of orthophosphate. In water sources with a relatively low concentration of orthophosphate (<0.1 mg / l), there are problems of inaccurate detection results and low sensitivity; while the reducing agent ascorbic acid used in the molybdenum blue spectrophotometry has a short shelf life, and the blue complex is easy to block the pipeline, which is not suitable for use in scenarios without human presence for a long time. Summary of the Invention

[0005] Embodiments of the present invention provide an on-line monitoring method, a microfluidic chip assembly and a device for the concentration of orthophosphate, which can solve the problems of inaccurate detection results, low sensitivity and limited application scenarios in the method for detecting the concentration of orthophosphate in water sources in the related art.

[0006] To solve the above problems, an embodiment of the present invention discloses an on-line monitoring method for the concentration of orthophosphate, which is applied to a microfluidic chip assembly. The microfluidic chip assembly includes a first chip and a second chip, and the first chip is connected to the second chip. The method includes:

[0007] The first chip mixes a water sample to be measured and a detection reagent to obtain a first mixed solution. The detection reagent includes ammonium molybdate and ammonium metavanadate. The first mixed solution includes a first product, and the first product is obtained by the reaction of the water sample to be measured and the detection reagent.

[0008] The first chip determines a first absorbance value of the first mixed solution, and determines a first concentration of orthophosphate in the water sample to be measured based on the first absorbance value.

[0009] When the first concentration is less than or equal to the first threshold, the first chip transfers the first mixed solution to the second chip;

[0010] The second chip performs extraction processing on the first product in the first mixed solution to obtain a second mixed solution; the second mixed solution includes the first product and an extractant;

[0011] The second chip determines the second absorbance value of the second mixed solution and determines the second concentration of orthophosphate in the water sample to be measured based on the second absorbance value.

[0012] The present invention also discloses a microfluidic chip assembly, which includes a first chip and a second chip, and the first chip and the second chip are connected;

[0013] The first chip mixes the water sample to be measured and a detection reagent to obtain a first mixed solution; the detection reagent includes ammonium molybdate and ammonium metavanadate; the first mixed solution includes a first product, and the first product is obtained by the reaction of the water sample to be measured and the detection reagent; determines the first absorbance value of the first mixed solution and determines the first concentration of orthophosphate in the water sample to be measured based on the first absorbance value; and when the first concentration is less than or equal to the first threshold, transfers the first mixed solution to the second chip;

[0014] The second chip is used to perform extraction processing on the first product in the first mixed solution to obtain a second mixed solution; the second mixed solution includes the first product and an extractant; determines the second absorbance value of the second mixed solution and determines the second concentration of orthophosphate in the water sample to be measured based on the second absorbance value.

[0015] An embodiment of the present invention also discloses an electronic device, and the electronic device includes the microfluidic chip assembly as described above.

[0016] Compared with the prior art, the embodiments of the present invention have the following advantages:

[0017] An embodiment of the present invention provides an online monitoring method for orthophosphate concentration. First, the first chip in the microfluidic chip assembly mixes the water sample to be tested and the detection reagent and determines the first concentration of orthophosphate in the water sample to be tested based on the first absorbance value of the first mixed solution. When the first concentration is less than or equal to the first threshold value, it indicates that the orthophosphate concentration in the water sample to be tested is low, and the first concentration determined by the first chip may have a large deviation. In this case, the first chip transmits the first mixed solution to the second chip in the microfluidic chip assembly, so that the second chip can extract the first product in the first mixed solution to obtain a second mixed solution, and based on the second absorbance value of the second mixed solution, the first product in the first mixed solution is extracted. Determine the second concentration of orthophosphate in the water sample to be tested; when the orthophosphate concentration in the water sample to be tested is low, extract and enrich the first product in the first mixed solution through the second chip, thereby increasing the concentration of the first product in the second mixed solution, thereby improving the accuracy and sensitivity of the second concentration of orthophosphate in the water sample to be tested determined based on the second absorbance value of the second mixed solution; in addition, the detection reagent used in the embodiment of the present invention has a long shelf life, and will not generate complexes to block pipelines, and can be automatically operated for a long time without supervision, thereby improving the degree of automation of the detection process of the orthophosphate concentration in the water sample to be tested, and expanding the application scope of the online monitoring method of the orthophosphate concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0019] Figure 1 It is a flow chart of steps of an online monitoring method of orthophosphate concentration of the present invention;

[0020] Figure 2 is a schematic diagram of a top view of the structure of a second chip of the present invention;

[0021] Figure 3 is a schematic diagram of a top view of another second chip of the present invention;

[0022] Figure 4 It is a schematic cross-sectional view of a channel along the channel diameter direction of the present invention;

[0023] Figure 5 is a schematic diagram of a top view of a first chip of the present invention;

[0024] Figure 6 It is a structural block diagram of a microfluidic chip component of the present invention. Specific Embodiments

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the protection scope of the present invention.

[0026] The terms "first", "second", etc. in the specification and claims of the present invention are used to distinguish similar objects, rather than to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same category, and the number of objects is not limited. For example, the first object can be one or more. In addition, the term "and / or" in the specification and claims is used to describe the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after. In the embodiments of the present invention, the term "plurality" refers to two or more, and other quantifiers are similar.

[0027] Method Embodiment

[0028] Refer to Figure 1 , which shows a step flowchart of an on-line monitoring method for the concentration of orthophosphate provided by the embodiments of the present invention. The method specifically includes the following steps S101 to S105:

[0029] Step S101: The first chip mixes the water sample to be measured and the detection reagent to obtain a first mixed solution; the detection reagent includes ammonium molybdate and ammonium metavanadate; the first mixed solution includes a first product, and the first product is obtained by the reaction of the water sample to be measured and the detection reagent.

[0030] Step S102: The first chip determines the first absorbance value of the first mixed solution and determines the first concentration of orthophosphate in the water sample to be measured based on the first absorbance value.

[0031] Step S103: When the first concentration is less than or equal to the first threshold, the first chip transfers the first mixed solution to the second chip.

[0032] Step S104: The second chip performs extraction treatment on the first product in the first mixed solution to obtain a second mixed solution; the second mixed solution includes the first product and an extractant.

[0033] Step S105: The second chip determines the second absorbance value of the second mixed solution, and determines the second concentration of orthophosphate in the water sample to be measured based on the second absorbance value.

[0034] The on-line monitoring method for the concentration of orthophosphate provided by the embodiment of the present invention can be applied to a microfluidic chip assembly, and the microfluidic chip assembly includes a first chip and a second chip connected to each other. Among them, the first chip can be a microfluidic chip supporting the vanadium molybdate yellow spectrophotometry method, and the second chip can be a microfluidic control chip supporting the extraction function and the vanadium molybdate yellow spectrophotometry method.

[0035] Specifically, the first chip includes a first sample inlet and a first sample outlet, the second chip includes a second sample inlet and a second sample outlet, and the first sample outlet is connected to the second sample inlet.

[0036] The first sample inlet is used to obtain the water sample to be measured from the water source, and input the water sample to be measured and the detection reagent into the first chip for the first chip to perform the operations corresponding to Step S101, Step S102, and Step S103; among them, the water source can include but is not limited to the water source at the domestic wastewater discharge outlet, the water source at the industrial wastewater discharge outlet, river water, lake water, etc.; the water sample to be measured is the water sample that needs to be detected for the concentration of orthophosphate obtained from the water source.

[0037] The first sample outlet is used to transfer the first mixed solution to the second sample inlet of the second chip when the first concentration is less than or equal to the first threshold, and the first sample outlet is also used to discharge the first mixed solution into the waste liquid collection container when the first concentration is greater than the first threshold.

[0038] The second sample inlet is used to input the first mixed solution and the extractant into the second chip for the second chip to perform the operations corresponding to Step S104 and Step S105.

[0039] The second sample outlet is used to discharge the second mixed solution and the first mixed solution after extraction treatment into the waste liquid collection container; it can be understood that the waste liquid collection container can include a first collection container and a second collection container, the first collection container is used to collect the first mixed solution in the aqueous phase and the first mixed solution after extraction treatment, and the second collection container is used to collect the second mixed solution in the organic phase.

[0040] The embodiment of the present invention uses the vanadium molybdate yellow spectrophotometry method to detect the concentration of orthophosphate in the water sample to be measured, and the detection reagent corresponding to the vanadium molybdate yellow spectrophotometry method includes ammonium molybdate and ammonium metavanadate acidic solution.

[0041] It is understandable that after the first chip mixes the water sample to be tested and the detection reagent, a first mixed solution is obtained. In the first mixed solution, the orthophosphate in the water sample to be tested reacts with ammonium molybdate and ammonium metavanadate in the detection reagent in an acidic environment to form a first product, and the first product is yellow phosphovanadomolybdic acid.

[0042] After obtaining the first mixed solution, the first chip measures the absorbance value of the first mixed solution at a preset wavelength based on the vanadium molybdate yellow spectrophotometry method, and determines the absorbance value of the first mixed solution at the preset wavelength as the first absorbance value. Among them, the preset wavelength can be any wavelength between 400 nm and 420 nm.

[0043] After obtaining the first absorbance value, the first chip searches for the orthophosphate concentration corresponding to the first absorbance value based on the first absorbance value, and determines the orthophosphate concentration corresponding to the first absorbance value found as the first concentration. Specifically, before step S101, orthophosphate solutions with different concentrations can be prepared, and the absorbance values of the mixed solutions corresponding to the orthophosphate solutions with different concentrations and the detection reagent are measured respectively at the measurement temperature by the vanadium molybdate yellow spectrophotometry method, and the absorbance values corresponding one-to-one to the orthophosphate concentration at the measurement temperature are obtained. And based on the one-to-one correspondence between the orthophosphate concentration and the absorbance value at the measurement temperature, a calibration table or calibration curve of the orthophosphate concentration corresponding to the measurement temperature is generated. In step S102, when the first absorbance value is obtained, the first chip can search for the orthophosphate concentration corresponding to the first absorbance value from the calibration table or calibration curve of the orthophosphate concentration corresponding to the measurement temperature based on the first absorbance value, and determine the orthophosphate concentration corresponding to the first absorbance value as the first concentration. Among them, the measurement temperature is the working temperature when the microfluidic chip assembly performs on-line monitoring; the number of measurement temperatures can be at least one. Before step S101, a calibration table or calibration curve of the orthophosphate concentration corresponding to each measurement temperature can be generated, so that the microfluidic chip assembly can, in step S102, determine the calibration table or calibration curve of the orthophosphate concentration corresponding to the current working temperature based on the current working temperature, and search for the orthophosphate concentration corresponding to the first absorbance value from the calibration table or calibration curve of the orthophosphate concentration corresponding to the current working temperature based on the first absorbance value, and determine the orthophosphate concentration corresponding to the first absorbance value as the first concentration.

[0044] Optionally, in one embodiment, a temperature control unit may be integrated in the microfluidic chip assembly. The temperature control unit is used to control the operating temperature of the microfluidic chip assembly at the target measurement temperature. Before step S101, the first chip may only generate a calibration table or a calibration curve of the orthophosphate concentration corresponding to the target measurement temperature. Due to the presence of the temperature control unit, the operating temperature of the microfluidic chip can be maintained at the target measurement temperature. In step S102 of the microfluidic chip assembly, the orthophosphate concentration corresponding to the first absorbance value can be directly found from the calibration table or the calibration curve of the orthophosphate concentration, and the orthophosphate concentration corresponding to the first absorbance value can be determined as the first concentration. This embodiment can be applied to extremely cold or hot regions where the operating temperature of the microfluidic chip assembly is extreme. Among them, the target measurement temperature is a temperature determined in advance that is suitable for the microfluidic chip assembly to perform on-line monitoring.

[0045] In the embodiment of the present invention, when the first concentration is greater than the first threshold, it indicates that the orthophosphate concentration in the water sample to be tested is relatively high. Within the detection range of the first chip, the accurate concentration of orthophosphate in the water sample to be tested can be determined by the first chip. At this time, the microfluidic chip assembly can determine the first concentration determined in step S102 as the measured concentration of orthophosphate in the water sample to be tested.

[0046] When the first concentration is less than or equal to the first threshold, it indicates that the orthophosphate concentration in the water sample to be tested is relatively low, and this concentration is lower than the detection range of the first chip. The first concentration determined by the first chip is larger than the actual concentration of orthophosphate in the water sample to be tested. In this case, the microfluidic chip assembly can use the second chip to execute steps S104 and S105, and determine the second concentration determined in step S105 as the measured concentration of orthophosphate in the water sample to be tested.

[0047] Among them, the first threshold can be determined according to the lower limit value of the detection range of the first chip. When the orthophosphate concentration in the water sample to be tested is lower than the lower limit value, the first chip will not be able to detect the actual concentration of orthophosphate in the water sample to be tested. At this time, the first chip usually determines the lower limit value of the detection range as the first concentration of orthophosphate in the water sample to be tested, so that the first concentration determined by the first chip is larger than the actual concentration of orthophosphate in the water sample to be tested. By steps S104 to S105 in the embodiment of the present invention, the accuracy of orthophosphate concentration detection can be improved when the orthophosphate concentration in the water sample to be tested is relatively low.

[0048] Exemplarily, the first threshold may be 0.1 mg / l.

[0049] In an embodiment of the present invention, when the first concentration is less than or equal to the first threshold, the first sample outlet of the first chip transfers the first mixed solution in the first chip to the second inlet of the second chip. The first mixed solution and the extractant are input into the second chip through the second inlet, and the second chip mixes the first mixed solution and the extractant. The extractant is used to extract the first product in the first mixed solution, and the extractant extracting the first product is determined as the second mixed solution. The first mixed solution after the extraction treatment can be discharged through the second outlet of the second chip after step S104.

[0050] Among them, the extractant may include, but is not limited to, alcohols and esters, etc.

[0051] After obtaining the second mixed solution, the second chip measures the absorbance value of the second mixed solution at a preset wavelength based on the vanadium molybdate yellow spectrophotometry, and determines the absorbance value of the second mixed solution at the preset wavelength as the second absorbance value.

[0052] After obtaining the first absorbance value, the second chip looks up the orthophosphate concentration corresponding to the second absorbance value from the orthophosphate concentration calibration table or the orthophosphate concentration calibration curve based on the second absorbance value, and determines the orthophosphate concentration corresponding to the second absorbance value as the second concentration. It should be noted that the method by which the second chip determines the second concentration of orthophosphate in the water sample to be measured based on the second absorbance value is the same as the method by which the first chip determines the first concentration of orthophosphate in the water sample to be measured based on the first absorbance value, and will not be elaborated here.

[0053] It can be understood that the microfluidic chip may further include a power pump for providing transmission power for the solutions in the first chip and the second chip. Among them, the power pump may include, but is not limited to, syringe pumps, peristaltic pumps, etc.

[0054] In an embodiment of the present invention, after determining the measured concentration of orthophosphate in the water sample to be measured, the microfluidic chip assembly may transmit the measured concentration to the target electronic device. The target electronic device analyzes and records the measured concentration, and when the measured concentration meets the alarm condition, an alarm message is sent to the relevant personnel. Among them, the target electronic device is a device for analyzing and recording the measured concentration of orthophosphate in the water sample to be measured. The target electronic device may be an electronic device that establishes a communication connection with the microfluidic chip assembly, or an electronic device equipped with the microfluidic chip assembly; the alarm condition may be that the measured concentration of orthophosphate in the water sample to be measured is greater than or equal to the second threshold.

[0055] The related technologies usually use the vanadium molybdenum yellow spectrophotometry or the phosphomolybdenum blue spectrophotometry to detect the concentration of orthophosphate in water sources. The principle of the vanadium molybdenum yellow spectrophotometry is as follows: in an acidic medium, the orthophosphate in the water sample to be measured reacts with ammonium molybdate and ammonium metavanadate to form yellow phosphovanadomolybdic acid. The absorbance of phosphovanadomolybdic acid is proportional to the content of orthophosphate in the water source. Based on the absorbance of phosphovanadomolybdic acid, the content of orthophosphate in the water source can be determined. The principle of the phosphomolybdenum blue spectrophotometry is as follows: in an acidic medium, the orthophosphate in the water sample to be measured reacts with ammonium molybdate to form phosphomolybdic heteropolyacid, and the phosphomolybdic heteropolyacid can be reduced by ascorbic acid to form a blue complex. The absorbance of this blue complex is proportional to the content of orthophosphate in the water source. Based on the absorbance of the blue complex, the content of orthophosphate in the water source can be determined. For the phosphomolybdenum blue spectrophotometry, the shelf life of the reducing agent ascorbic acid is relatively short (usually 1 month), and the blue complex generated in the phosphomolybdenum blue spectrophotometry is also prone to clogging the pipeline of the testing device, requiring relevant personnel to maintain and process it in a timely manner. It is not suitable for use in scenarios with long-term unattended operation. In addition, the phosphomolybdenum blue spectrophotometry requires a large amount of detection reagents, resulting in a large amount of waste liquid and increasing the detection cost. And the detection time of the phosphomolybdenum blue spectrophotometry increases with the increase of the orthophosphate concentration in the water sample to be measured. The detection time is usually more than 20 minutes, and the detection efficiency is low. In the existing vanadium molybdenum yellow spectrophotometry, although it will not generate complexes to clog the pipeline, it is only suitable for detecting the orthophosphate concentration in water samples with a relatively high orthophosphate concentration. In the case of a relatively low orthophosphate concentration in the water sample to be measured, there is a problem of inaccurate detection results. Further, the volume of the detection equipment for detecting the orthophosphate concentration in the related technologies is generally large, and to maintain the working temperature of the detection equipment at a certain measurement temperature, a special air-conditioned room needs to be provided for the detection equipment, which further increases the detection cost.

[0056] The on-line monitoring method for the concentration of orthophosphate provided by the embodiments of the present invention first mixes the water sample to be measured and the detection reagent in the first chip of the microfluidic chip assembly and determines the first concentration of orthophosphate in the water sample to be measured based on the first absorbance value of the first mixed solution. When the first concentration is less than or equal to the first threshold, it indicates that the concentration of orthophosphate in the water sample to be measured is relatively low, and there may be a large deviation in the first concentration determined by the first chip. In this case, the first chip transfers the first mixed solution to the second chip in the microfluidic chip assembly, so that the second chip can extract the first product in the first mixed solution to obtain a second mixed solution, and determine the second concentration of orthophosphate in the water sample to be measured based on the second absorbance value of the second mixed solution; when the concentration of orthophosphate in the water sample to be measured is relatively low, the second chip extracts and enriches the first product in the first mixed solution, which increases the concentration of the first product in the second mixed solution, thereby improving the accuracy of the second concentration of orthophosphate in the water sample to be measured determined based on the second absorbance value of the second mixed solution; further, the detection reagent adopted by the embodiments of the present invention has a long shelf life and does not generate complexes to block the pipeline, and can operate automatically for a long time without human supervision, which improves the automation degree of the process of detecting the concentration of orthophosphate in the water sample to be measured and expands the application range of the on-line monitoring method for the concentration of orthophosphate; the on-line monitoring method for the concentration of orthophosphate provided by the embodiments of the present invention can realize the detection of the concentration of orthophosphate in the water sample to be measured with only a small amount of detection reagent, reduces the consumption of the detection reagent, thereby reducing the generation of waste liquid and lowering the detection cost; and the embodiments of the present invention can complete the whole process of pipeline flushing, detection of the concentration of orthophosphate in the water sample to be measured, and waste liquid discharge within 2 minutes to 3 minutes, which improves the detection efficiency of detecting the concentration of orthophosphate. Further, the embodiments of the present invention can realize the on-line monitoring of the concentration of orthophosphate by using a microfluidic chip assembly, and the volume of the detection device is small. By integrating a temperature control unit in the microfluidic chip assembly, the working temperature of the microfluidic chip assembly can be maintained at the target measurement temperature, which further reduces the detection cost of on-line monitoring the concentration of orthophosphate in the water sample to be measured while improving the detection accuracy and detection efficiency.

[0057] Optionally, in one embodiment, the second chip has a second sampling part, an extraction part and a second detection part. The second sampling part is connected to the inlet of the extraction part, and the outlet of the extraction part is connected to the second detection part; the connection between the first chip and the second chip includes: the second sampling part is connected to the first chip.

[0058] The step S104 in which the second chip extracts the first product in the first mixed solution to obtain a second mixed solution includes steps S1041 to S1042:

[0059] Step S1041: The second chip injects the first mixed solution and the extractant into the extraction part by using the second sample injection part.

[0060] Step S1042: The second chip uses the extractant to perform extraction processing on the first product in the first mixed solution in the extraction part to obtain a second mixed solution.

[0061] Specifically, when the first concentration is less than or equal to the first threshold, the second chip first injects the first mixed solution and the extractant into the extraction part by using the second sample injection part; then uses the extractant to perform extraction processing on the first product in the first mixed solution in the extraction part to obtain a second mixed solution; then, transmits the second mixed solution to the second detection part; finally, uses the second detection part to determine the second absorbance value of the second mixed solution, and determines the second concentration of orthophosphate in the water sample to be measured based on the second absorbance value.

[0062] Refer to Figure 2 , which shows a top view structural schematic diagram of a second chip provided by an embodiment of the present invention. As Figure 2 shown, the second chip 20 has a second sample injection part 21, an extraction part 22, and a second detection part 23. The second sample injection part 21 is connected to the inlet of the extraction part 22, and the outlet of the extraction part 22 is connected to the second detection part 23.

[0063] Among them, the second sample injection part 21 includes a second sample injection port 211 and a second sample injection port 212. The second sample injection port 211 is used to inject the extractant into the extraction part 22, and the second sample injection port 212 is used to inject the first mixed solution into the extraction part 22. The second sample injection part 21 is connected to the first sample outlet of the first chip through the second sample injection port 212. It should be noted that the microfluidic chip assembly can simultaneously inject the extractant and the first mixed solution into the extraction part 22 by using the second sample injection port 211 and the second sample injection port 212, or can first inject the extractant into the extraction part 22 by using the second sample injection port 211, and then inject the first mixed solution into the extraction part 22 by using the second sample injection port 212. The embodiments of the present invention do not limit this.

[0064] In addition, as an optional implementation manner, the second sample injection part 21 may also only include one sample injection port, and the microfluidic chip assembly can use this sample injection port to sequentially inject the extractant and the first mixed solution into the extraction part 22.

[0065] The extraction section 22 is used to extract the first product in the first mixed solution using an extractant to obtain a second mixed solution; the extraction section 22 is connected to the second injection section 21 and the second detection section 23 respectively, and a second sample outlet 241 is provided between the extraction section 22 and the second detection section 23; the microfluidic component extracts the first product in the first mixed solution using an extractant in the extraction section 22, and after obtaining the second mixed solution, the second mixed solution can be transferred to the second detection section 23, and the first mixed solution after the extraction treatment can be transferred to the second sample outlet 241, and discharged through the second sample outlet 241.

[0066] In the embodiment of the present invention, the second sample outlet includes a second sample outlet 241 and a second sample outlet 242. The second sample outlet 241 is used to discharge the first mixed solution after the extraction process, and the second sample outlet 242 is used to discharge the second mixed solution detected by the second detection unit 23. After the second chip determines the second concentration of orthophosphate in the water sample to be tested by the second detection unit 23, the second mixed solution is discharged through the second sample outlet 242.

[0067] It is understandable that the second detection unit 23 includes a cuvette 231, and in the process of determining the second absorbance value of the second mixed solution, the cuvette 231 in the second detection unit 23 is used as a reference background to determine the second absorbance value of the second mixed solution at a preset wavelength.

[0068] In the online monitoring method of orthophosphate concentration provided by an embodiment of the present invention, a second sampling part, an extraction part and a second detection part which are connected in sequence are arranged in the second chip. When the first concentration is less than or equal to the first threshold value, the second chip uses the second sampling part to inject the first mixed solution and the extractant into the extraction part, and uses the extractant in the extraction part to extract the first product in the first mixed solution to obtain a second mixed solution. The first product in the first mixed solution is enriched in the extraction part, thereby increasing the concentration of the first product in the second solution, thereby improving the accuracy of the second concentration determined by step S105.

[0069] Optionally, in one embodiment, the extraction part includes a curved channel; the inlet of the channel is connected to the second injection part, and the outlet of the channel is connected to the second detection part.

[0070] In an embodiment of the present invention, in order to improve the extraction effect of the first product and extract as much of the first product in the first mixed solution into the extractant as possible to obtain the second mixed solution, a tortuous channel can be provided in the extraction section so that the extractant and the first mixed solution can fully collide and mix in the process of flowing through the tortuous channel in the extraction section, thereby increasing the contact probability between the first product in the first mixed solution and the extractant, speeding up the extraction process and improving the extraction effect of the first product.

[0071] As an implementation manner, referring to Figure 2 , the bent channels 221 in the extraction part 22 can be interconnected "S-shaped" channels. As another implementation manner, referring to Figure 3 , a top view structural schematic diagram of another second chip provided by an embodiment of the present invention is shown, and the bent channels 221 in the extraction part 22 can be interconnected broken-line channels. As still another implementation manner, the bent channels in the extraction part can also be interconnected "C-shaped" channels.

[0072] It can be understood that arranging bent channels in the extraction part can enable the first mixed solution and the extractant to be fully mixed during the process of flowing through the extraction part. The shape of the bent channels and the length of the bent channels can be determined according to the extraction effect. Exemplarily, the length of the bent channels can be 0.5 meters to 2 meters. The embodiments of the present invention do not specifically limit the shape of the bent channels and the length of the bent channels.

[0073] Optionally, in one implementation manner, the second chip includes a bottom plate and a cover plate. The bottom plate has the second sample introduction part, the extraction part, and the second detection part; the channels include a first sub-channel and a second sub-channel; the first sub-channel and the second sub-channel are separated from each other in a first area far from the cover plate, and the first sub-channel and the second sub-channel are interconnected in a second area close to the cover plate.

[0074] Among them, the bottom plate is used to carry the second sample introduction part, the extraction part, and the second detection part of the second chip; the cover plate is used to protect the second sample introduction part, the extraction part, and the second detection part in the bottom plate. The bottom plate is made of the high molecular polymer polydimethylsiloxane (PDMS). Specifically, a mold with the required size and channel structure can be prepared by ultraviolet lithography technology, and then the PDMS molten liquid that has been vacuum degassed is poured on the mold, and it can be solidified by baking at 60 °C for 2 hours to obtain the above bottom plate. The cover plate and the bottom plate can be bonded by oxygen plasma bonding; it can be understood that the bonding method between the cover plate and the bottom plate is not limited to the oxygen plasma bonding method provided by the embodiments of the present invention. In actual application scenarios, a suitable method can be selected according to needs to bond the cover plate and the bottom plate. The embodiments of the present invention do not specifically limit this.

[0075] In the embodiment of the present invention, during the extraction process, to improve the separation effect between the second mixed solution and the first mixed solution, a first sub-channel and a second sub-channel which are separated from each other may be arranged in a first area away from the cover plate in the channel. The first mixed solution is transmitted through the first sub-channel, and the second mixed solution is transmitted through the second sub-channel, which facilitates transmitting the second mixed solution to the second detection unit after the extraction process, and discharging the first mixed solution after the extraction process through the second sample outlet. In addition, the first sub-channel and the second sub-channel communicate with each other in a second area close to the cover plate, so that the first mixed solution transmitted in the first channel and the second mixed solution transmitted in the second sub-channel collide and mix when passing through the bent part in the channel, so as to achieve the purpose of extracting the first product.

[0076] It can be understood that the smaller the diameter of the bent channel in the extraction unit, the greater the surface tension of the liquid transmitted in the channel. In the embodiment of the present invention, the diameter of the bent channel in the extraction unit is less than 300 μm, and the extraction agent transmitted in the channel has a large surface tension. Therefore, the extraction of the first product in the first mixed solution can be realized based on the surface tension of the extraction agent.

[0077] Refer to Figure 4 , which shows a schematic cross-sectional view of a channel along the channel diameter direction provided by an embodiment of the present invention. As Figure 4 shown, the channel 221 includes a first sub-channel 01 and a second sub-channel 02. In a first area 221-1 of the channel 221 away from the cover plate, the first sub-channel 01 and the second sub-channel 02 are separated from each other. In a second area 221-2 of the channel 221 close to the cover plate, the first sub-channel 01 and the second sub-channel 02 communicate with each other.

[0078] It should be noted that the magnitude of a first length of the first area 221-1 along the direction from the bottom plate to the cover plate and a second length of the second area 221-2 along the direction from the bottom plate to the cover plate can be determined according to the extraction effect of the first product in the first mixed solution and the separation effect between the first mixed solution and the second mixed solution. Exemplarily, the first length may be 1 / N of the second length, and the value range of N is from 1 to 3.

[0079] The on-line monitoring method for the orthophosphate concentration provided by the embodiment of the present invention, while ensuring the extraction effect of the first product in the first mixed solution, is also beneficial to separating the second mixed solution and the first mixed solution after the extraction process, and improves the efficiency of detecting the orthophosphate concentration.

[0080] Optionally, in one embodiment, the first volume of the first mixed solution is M times the second volume of the extractant, where M ranges from 1 to 100. For example, M can be one of 1, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 or any range value between any two of them.

[0081] Optionally, in one embodiment, the first chip has a first sample inlet part, a mixing reaction part, and a first detection part. The first sample inlet part is connected to the inlet of the mixing reaction part, and the outlet of the mixing reaction part is connected to the first detection part. The connection between the first chip and the second chip includes: the first detection part is connected to the second chip. Step S101: The first chip mixes the water sample to be measured and the detection reagent to obtain a first mixed solution, including steps S1011 to S1012:

[0082] Step S1011: The first chip uses the first sample inlet part to inject the water sample to be measured and the detection reagent into the mixing reaction part.

[0083] Step S1012: The first chip uses the mixing reaction part to mix the water sample to be measured and the detection reagent to obtain a first mixed solution.

[0084] Specifically, the first chip first uses the first sample inlet part to inject the water sample to be measured and the detection reagent into the mixing reaction part; then, uses the mixing reaction part to mix the water sample to be measured and the detection reagent to obtain a first mixed solution; then, transmits the first mixed solution to the first detection part; finally, uses the first detection part to determine the first absorbance value of the first mixed solution and determine the first concentration of orthophosphate in the water sample to be measured based on the first absorbance value.

[0085] Referring to Figure 5 , a top view structural schematic diagram of a first chip provided by an embodiment of the present invention is shown. As Figure 5 shown, the first chip 10 has a first sample inlet part 11, a mixing reaction part 12, and a first detection part 13. The first sample inlet part 11 is connected to the inlet of the mixing reaction part 12, and the outlet of the mixing reaction part 12 is connected to the first detection part 13.

[0086] Among them, the first sample inlet part 11 includes a first sample inlet 111, a first sample inlet 112, and a first sample inlet 113. The first sample inlet 111 is used to inject the detection reagent into the mixing reaction part 12, the first sample inlet 112 is used to inject the water sample to be measured into the mixing reaction part 12, and the first sample inlet 113 is used to inject pure water into the mixing reaction part 12.

[0087] It should be noted that pure water is injected into the mixing reaction part 12 through the first sampling port 113 to determine the absorbance value when the orthophosphate concentration is 0 in the orthophosphate concentration calibration table or the orthophosphate concentration calibration curve before step S101, and to flush the pipeline in the first chip with pure water before step S101. Specifically, when pure water is injected into the mixing reaction part 12 through the first sampling port 113 before step S101 to determine the absorbance value when the orthophosphate concentration is 0 in the orthophosphate concentration calibration table or the orthophosphate concentration calibration curve, the first sampling part 11 needs to simultaneously inject the detection reagent into the mixing reaction part 12 through the first sampling port 111. The flow rate of injecting the detection reagent into the mixing reaction part 12 can be 50 μl / min, and the flow rate of injecting pure water into the mixing reaction part 12 can be 100 μl / min. When flushing the pipeline in the first chip with pure water before step S101, the first sampling part 11 can only inject pure water into the mixing reaction part 12 through the first sampling port 113, so that the pure water can flow through the first sampling part 11, the mixing reaction part 12 and the first detection part 13 in sequence, realizing the flushing of the first chip 10. After flushing the pipeline in the first chip, the operations corresponding to steps S101 to S102 are performed to avoid the influence of impurities in the pipeline on the detection result and improve the accuracy of determining the first concentration.

[0088] The mixing reaction part 12 is used to mix the detection reagent injected by the first sampling part 11 and the water sample to be measured, so that the orthophosphate in the water sample to be measured reacts with ammonium molybdate and ammonium metavanadate in the detection reagent to generate a first product. The mixing reaction part 12 is respectively connected to the first sampling part 11 and the first detection part 13. After the first chip mixes the water sample to be measured and the detection reagent by using the mixing reaction part 12 to obtain a first mixed solution, the first mixed solution can be transmitted to the first detection part 13.

[0089] After the first chip determines the first absorbance value of the first mixed solution by using the first detection part 13 and determines the first concentration of orthophosphate in the water sample to be measured based on the first absorbance value, when the first concentration is less than or equal to the first threshold, the first mixed solution can be transmitted to the second chip through the first sampling port 142. When the first concentration is greater than the first threshold, the first mixed solution can be discharged through the first sampling port 141, and the first concentration is determined as the measured concentration of orthophosphate in the water sample to be measured. It can be understood that when the first concentration is greater than the first threshold, the operations corresponding to steps S103 to S105 are not continued.

[0090] In an embodiment of the present invention, the first sample outlet includes a first sample outlet 141 and a first sample outlet 142. The first sample outlet 141 is used to discharge the first mixed solution, and the first sample outlet 142 is used to transfer the first mixed solution to the second chip.

[0091] It can be understood that the first detection unit 13 also includes a cuvette 131. In the process of determining the first absorbance value of the first mixed solution, the cuvette 131 in the first detection unit 13 is used as a reference background to determine the first absorbance value of the first mixed solution at a preset wavelength.

[0092] Optionally, in one embodiment, the mixing reaction unit 12 may also include a bent channel 121 that is the same or similar to that in the extraction unit. The inlet of the channel 121 is connected to the first sample inlet unit 11, and the outlet of the channel 121 is connected to the first detection unit 13.

[0093] Among them, the shape of the cross-section of the bent channel in the mixing reaction unit along the diameter direction can be circular, and the diameter of the circle can be any value less than 300 μm. Exemplarily, the channel diameter can be 200 μm or 100 μm.

[0094] Optionally, in one embodiment, the first chip in step S102 determines the first concentration of orthophosphate in the water sample to be measured based on the first absorbance value, including steps S1021 to S1022:

[0095] Step S1021, the first chip determines, according to the first absorbance value, the orthophosphate concentration corresponding to the first absorbance value from a first calibration curve; the first calibration curve is used to indicate the one-to-one correspondence between the absorbance value and the orthophosphate concentration.

[0096] Step S1022, the first chip determines the orthophosphate concentration corresponding to the first absorbance value as the first concentration.

[0097] Among them, the first calibration curve can be a curve fitted based on the correspondence between the orthophosphate concentration and the absorbance at a previously determined measurement temperature.

[0098] Optionally, in one embodiment, the method further includes steps A11 to A14:

[0099] Step A11, the first chip mixes a positive phosphate solution with a first preset concentration and the detection reagent to obtain a third mixed solution.

[0100] Step A12, the first chip determines the third absorbance value of the third mixed solution.

[0101] Step A13: The first chip mixes the orthophosphate solution with the second preset concentration and the detection reagent to obtain a fourth mixed solution.

[0102] Step A14: The first chip determines the fourth absorbance value of the fourth mixed solution.

[0103] Step A15: The first chip generates a first calibration curve based on the third absorbance value, the fourth absorbance value, the first preset concentration, and the second preset concentration.

[0104] In an embodiment of the present invention, the first chip can also determine the first calibration curve based on the third absorbance value corresponding to the orthophosphate solution with the first preset concentration and the fourth absorbance value corresponding to the orthophosphate solution with the second preset concentration through steps A11 to A15.

[0105] Specifically, the first preset concentration and the second preset concentration can be any concentrations that are different from each other. Exemplarily, the first preset concentration can be 0, and the second preset concentration can be 80% of the detection range of the first chip. When the detection range of the first chip is 0 to 5 mg / l, the second preset concentration can be 4 mg / l.

[0106] The first chip generates a first calibration curve based on the third absorbance value, the fourth absorbance value, the first preset concentration, and the second preset concentration specifically as follows: Based on the third absorbance value corresponding to the first preset concentration and the fourth absorbance value corresponding to the second preset concentration, a straight line with the orthophosphate concentration as the abscissa and the absorbance value as the ordinate is determined as the first calibration curve. In the first calibration curve, the absorbance value and the orthophosphate concentration correspond one by one. In the process of determining the first concentration of orthophosphate in the water sample to be measured based on the first absorbance value in step S102, the orthophosphate concentration corresponding to the first absorbance value can be determined from the first calibration curve determined in step A15, and the orthophosphate concentration corresponding to the first absorbance value is determined as the first concentration.

[0107] It can be understood that the first chip can determine the first calibration curve corresponding to any measurement temperature through steps A11 to A15.

[0108] Optionally, in an implementation manner, step S105 where the second chip determines the second concentration of orthophosphate in the water sample to be measured based on the second absorbance value includes steps S1051 to S1052:

[0109] Step S1051: The second chip determines the orthophosphate concentration corresponding to the second absorbance value from the second calibration curve according to the second absorbance value; the second calibration curve is used to indicate the one-to-one correspondence between the absorbance value and the orthophosphate concentration.

[0110] Step S1052: The second chip determines the orthophosphate concentration corresponding to the second absorbance value as the second concentration.

[0111] The second calibration curve can be a curve fitted based on the corresponding relationship between the orthophosphate concentration and the absorbance at a previously determined measurement temperature.

[0112] Optionally, in one implementation, the method further includes steps A21 to A25:

[0113] Step A21: The second chip mixes a third preset concentration of orthophosphate solution and an extractant to obtain a fifth mixed solution;

[0114] Step A22: The second chip determines the fifth absorbance value of the fifth mixed solution;

[0115] Step A23: The second chip mixes a fourth preset concentration of orthophosphate solution and an extractant to obtain a sixth mixed solution;

[0116] Step A24: The second chip determines the sixth absorbance value of the sixth mixed solution;

[0117] Step A25: The second chip generates a second calibration curve based on the fifth absorbance value, the sixth absorbance value, the third preset concentration, and the fourth preset concentration; the second calibration curve is used to indicate the one-to-one correspondence between the absorbance value and the orthophosphate concentration.

[0118] Specifically, the third preset concentration and the fourth preset concentration can be any concentrations that are different from each other. Exemplarily, the third preset concentration can be 0, and the fourth preset concentration can be 80% of the detection range of the second chip. When the detection range of the second chip is 0 to 50 μg / l, the fourth preset concentration can be 40 μg / l; the volume ratio of the orthophosphate solution with the third preset concentration to the extractant is 5, and the volume ratio of the orthophosphate solution with the fourth preset concentration to the extractant is also 5.

[0119] Generating the second calibration curve based on the fifth absorbance value, the sixth absorbance value, the third preset concentration, and the fourth preset concentration is specifically: Based on the fifth absorbance value corresponding to the third preset concentration and the sixth absorbance value corresponding to the fourth preset concentration, a straight line with the orthophosphate concentration as the abscissa and the absorbance value as the ordinate is determined as the second calibration curve. In the second calibration curve, the absorbance value and the orthophosphate concentration are in one-to-one correspondence. In the process of determining the second concentration of orthophosphate in the water sample to be measured based on the second absorbance value in step S105, the orthophosphate concentration corresponding to the second absorbance value can be determined from the second calibration curve determined in step A25, and the orthophosphate concentration corresponding to the second absorbance value is determined as the second concentration.

[0120] It can be understood that the second chip can determine the second calibration curve corresponding to any measured temperature through steps A21 to A25.

[0121] Optionally, in one implementation, the microfluidic chip assembly can also determine the absorbance value corresponding to the mixed solution of the detection reagent and pure water with a phosphate concentration of 0 at a preset detection period; it can be understood that during the use of the first chip, the life of the first chip will continuously decrease. The absorbance value obtained in the first preset detection period is A1, and the absorbance value obtained in the second preset detection period is A2. When the difference between A2 and A1 is greater than the third threshold, it indicates that the colorimetric cuvette in the first detection unit of the first chip has reached the preset service life. At this time, the microfluidic chip assembly can notify relevant personnel through the target electronic device to replace the colorimetric cuvette in the first detection unit in a timely manner.

[0122] Correspondingly, the microfluidic chip assembly can also determine the absorbance value corresponding to the mixed solution of the extractant and pure water with a phosphate concentration of 0 at a preset detection period. The absorbance value obtained in the third preset detection period is B1, and the absorbance value obtained in the fourth preset detection period is B2. When the difference between B2 and B1 is greater than the fourth threshold, it indicates that the colorimetric cuvette in the second detection unit of the second chip has reached the preset service life. At this time, the microfluidic chip assembly can notify relevant personnel through the target electronic device to replace the colorimetric cuvette in the second detection unit in a timely manner, realizing the automatic judgment of the service life of the colorimetric cuvettes in the first detection unit of the first chip and the second detection unit of the second chip, and improving the automation degree of the microfluidic chip assembly for detecting the phosphate concentration.

[0123] The present invention will be described in detail below through embodiments.

[0124] Embodiment 1

[0125] (1) Preparation of the detection reagent:

[0126] First, weigh 40 g of ammonium molybdate and dissolve it in 400 mL of pure water to obtain an ammonium molybdate solution; then, weigh 1.0 g of ammonium metavanadate and dissolve it in a mixed solvent of 300 mL of pure water and 80 mL of concentrated sulfuric acid to obtain an ammonium metavanadate solution; then, add the ammonium molybdate solution to the ammonium metavanadate solution to obtain a first acidic solution; finally, add pure water to the first acidic solution and dilute the first acidic solution to 1 L to obtain an ammonium vanadomolybdate solution.

[0127] (2) Preparation of the phosphate solution:

[0128] Weigh 0.2197 ± 0.001 g of potassium dihydrogen phosphate (KH₂PO₄) that has been dried at 110 °C for 2 hours and cooled to room temperature; dissolve the potassium dihydrogen phosphate in pure water and transfer it to a 1000 mL volumetric flask. Add approximately 800 mL of pure water, 5 mL of sulfuric acid, dilute to the mark with pure water and mix well to obtain a stock solution of orthophosphate with a concentration of 50 mg / L; other orthophosphate solutions with lower concentrations are obtained by diluting this stock solution of orthophosphate.

[0129] (3) Pipeline flushing

[0130] Inject pure water into the mixing and reaction section using the first sample injection section, and the mixing and reaction section transmits the pure water to the first detection section. Finally, the pure water is discharged through the first sample outlet connected to the first detection section to achieve flushing of the pipeline in the first chip; among them, the flow rate of the injected pure water is 100 μl / min, and the injection duration of the pure water is 1 min.

[0131] (4) Generate the first calibration curve:

[0132] First, inject pure water (the first preset concentration is 0) and ammonium vanadomolybdate solution into the mixing and reaction section using the first sample injection section; use the mixing and reaction section to mix the pure water and ammonium vanadomolybdate solution to obtain a first calibration solution, and transmit the first calibration solution to the first detection section; use the first detection section to determine the third absorbance value of the first calibration solution at a preset wavelength with the quartz ultra-micro cuvette in the first detection section as the reference background; among them, the flow rate of the pure water is 100 μl / min, the flow rate of the ammonium vanadomolybdate solution is 50 μl / min, and the injection duration of the pure water and ammonium vanadomolybdate solution is 20 s;

[0133] After that, inject an orthophosphate solution with a concentration of 4 mg / L (the second preset concentration) and ammonium vanadomolybdate solution into the mixing and reaction section using the first sample injection section; use the mixing and reaction section to mix the orthophosphate solution and ammonium vanadomolybdate solution to obtain a second calibration solution, and transmit the second calibration solution to the first detection section; use the first detection section to determine the fourth absorbance value of the second calibration mixed solution at a wavelength of 420 nm with the quartz ultra-micro cuvette in the first detection section as the reference background; among them, the flow rate of the orthophosphate solution is 100 μl / min, the flow rate of the ammonium vanadomolybdate solution is 50 μl / min; the injection duration of the orthophosphate solution and ammonium vanadomolybdate solution is 20 s;

[0134] Finally, generate the first calibration curve based on the third absorbance value, the fourth absorbance value, the first preset concentration, and the second preset concentration.

[0135] (5) Standard sample test:

[0136] Inject a 1 mg / l orthophosphate solution and an ammonium vanadomolybdate solution into the mixing reaction part using the first sample injection part; mix the orthophosphate solution and the ammonium vanadomolybdate solution in the mixing reaction part to obtain a first standard mixed solution, and transfer the first standard mixed solution to the first detection part; use the quartz ultra-micro cuvette in the first detection part as a reference background, and use the first detection part to determine the absorbance value of the first standard mixed solution at a wavelength of 420 nm; determine the orthophosphate concentration corresponding to this absorbance value based on the first calibration curve generated in step (4); where the flow rate of the orthophosphate solution is 100 μl / min, and the flow rate of the ammonium vanadomolybdate solution is 50 μl / min; the injection duration of the orthophosphate solution and the ammonium vanadomolybdate solution is 20 s.

[0137] According to the same method, determine the orthophosphate concentrations corresponding to the second standard mixed solution, the third standard mixed solution, the fourth standard mixed solution, and the fifth standard mixed solution obtained by mixing orthophosphate solutions with concentrations of 2 mg / l, 3 mg / l, 4 mg / l, and 5 mg / l and ammonium vanadomolybdate solutions respectively. Referring to Table 1, a test result of the orthophosphate concentration provided by an embodiment of the present invention is shown. As shown in Table 1, the relative error between the orthophosphate concentration measured by the on-line monitoring method for the orthophosphate concentration provided by the embodiment of the present invention and the actual orthophosphate concentration is less than 0.005 mg / l, indicating that when the orthophosphate concentration is greater than 0.1 mg / l, the orthophosphate concentration measured by the on-line monitoring method for the orthophosphate concentration provided by the embodiment of the present invention has high accuracy and meets the requirements of the standard method.

[0138] Table 1

[0139] Standard solution concentration (mg / l) 1 2 3 4 5 Measured concentration in the embodiment of the present invention (mg / l) 1.001 1.998 2.997 3.995 5.005

[0140] (6) Repeatability test:

[0141] According to the on-line monitoring method described in step (5), repeat the determination of the orthophosphate concentrations corresponding to the first standard mixed solution, the second standard mixed solution, the third standard mixed solution, the fourth standard mixed solution, and the fifth standard mixed solution obtained by mixing orthophosphate solutions with concentrations of 1 mg / l, 2 mg / l, 3 mg / l, 4 mg / l, and 5 mg / l and ammonium vanadomolybdate solutions 3 times. The obtained test results are shown in Table 2. The relative standard deviation (RSD) between the measured concentrations obtained by repeatedly measuring the orthophosphate concentration in the orthophosphate solution with the same concentration using the on-line monitoring method for the orthophosphate concentration provided by the embodiment of the present invention is less than 0.4%, indicating that the on-line monitoring method for the orthophosphate concentration provided by the embodiment of the present invention has good repeatability and meets the requirements of the standard method.

[0142] Table 2

[0143]

[0144] Example 2

[0145] The preparation method of the detection reagent in Example 2 is the same as step (1) in Example 1, and the preparation method of the orthophosphate solution is the same as step (2) in Example 1;

[0146] (3) Pipeline flushing

[0147] Inject pure water into the mixing and reaction part by the first sample injection part, and the mixing and reaction part transports the pure water to the first detection part. The first detection part injects the pure water into the extraction part through the second sample injection port of the second chip through the first sample outlet. The extraction part transports the pure water to the second detection part, and finally discharges the pure water through the second sample outlet connected to the second detection part to realize the flushing of the pipelines in the first chip and the second chip; wherein, the flow rate of the injected pure water is 100 μl / min, and the injection duration of the pure water is 1.5 min.

[0148] (4) Generate the second calibration curve:

[0149] First, inject pure water (the third preset concentration is 0) and ammonium vanadomolybdate solution into the mixing and reaction part by the first sample injection part; the mixing and reaction part mixes the pure water and the ammonium vanadomolybdate solution to obtain the third calibration solution, and transports the third calibration solution to the first detection part; inject the third calibration solution into the extraction part of the second chip through the second sample injection part. Before that, the microfluidic chip assembly injects n-pentanol into the extraction part by the second sample injection part; in the extraction part, use n-pentanol to extract the first product in the third calibration solution to obtain the first extraction solution, and transport the first extraction solution to the second detection part; use the quartz ultra-micro cuvette in the second detection part as the reference background, and use the second detection part to determine the fifth absorbance value of the first extraction solution at a wavelength of 420 nm; wherein, the flow rate of the pure water is 100 ul / min, the flow rate of the ammonium vanadomolybdate solution is 50 ul / min, the injection duration of the pure water and the ammonium vanadomolybdate solution is 200 s; the volume ratio of n-pentanol to the third calibration solution is 10:1;

[0150] After that, use the first sample injection part to inject a potassium dihydrogen phosphate solution with a concentration of 50 μg / L (the fourth preset concentration) and an ammonium vanadomolybdate solution into the mixing reaction part; use the mixing reaction part to mix the potassium dihydrogen phosphate solution and the ammonium vanadomolybdate solution to obtain a fourth calibration solution, and transfer the fourth calibration solution to the first detection part; inject the fourth calibration solution into the extraction part of the second chip through the second sample injection part. Before that, the microfluidic chip assembly uses the second sample injection part to inject n-pentanol into the extraction part; use n-pentanol in the extraction part to extract the first product in the fourth calibration solution to obtain a second extraction solution, and transfer the second extraction solution to the second detection part; use the second detection part to determine the sixth absorbance value of the second extraction solution at a wavelength of 420 nm with the quartz ultra-micro cuvette in the second detection part as the reference background; among them, the flow rate of the potassium dihydrogen phosphate solution is 100 μL / min, the flow rate of the ammonium vanadomolybdate solution is 50 μL / min, and the injection duration of the potassium dihydrogen phosphate solution and the ammonium vanadomolybdate solution is 200 s; the volume ratio of n-pentanol to the fourth calibration solution is 10:1;

[0151] Finally, generate a second calibration curve based on the fifth absorbance value, the sixth absorbance value, the third preset concentration, and the fourth preset concentration.

[0152] (5) Standard sample test:

[0153] Use the first sample injection part to inject a potassium dihydrogen phosphate solution with a concentration of 10 μg / L and an ammonium vanadomolybdate solution into the mixing reaction part; use the mixing reaction part to mix the potassium dihydrogen phosphate solution and the ammonium vanadomolybdate solution to obtain a sixth standard mixed solution, and transfer the sixth standard mixed solution to the first detection part; inject the sixth standard mixed solution into the extraction part of the second chip through the second sample injection part. Before that, the microfluidic chip assembly uses the second sample injection part to inject n-pentanol into the extraction part; use n-pentanol in the extraction part to extract the first product in the sixth standard mixed solution to obtain a third extraction solution, and transfer the third extraction solution to the second detection part; use the second detection part to determine the absorbance value of the third extraction solution at a wavelength of 420 nm with the quartz ultra-micro cuvette in the second detection part as the reference background; among them, the flow rate of the potassium dihydrogen phosphate solution is 100 μL / min, the flow rate of the ammonium vanadomolybdate solution is 50 μL / min, and the injection duration of the potassium dihydrogen phosphate solution and the ammonium vanadomolybdate solution is 200 s; the volume ratio of n-pentanol to the sixth standard mixed solution is 10:1;

[0154] According to the same method, the corresponding orthophosphate concentrations of the seventh standard mixed solution, eighth standard mixed solution, ninth standard mixed solution, and tenth standard mixed solution obtained by mixing orthophosphate solutions with concentrations of 30 μg / l, 50 μg / l, 80 μg / l, and 100 μg / l and ammonium vanadomolybdate solution were determined respectively. Referring to Table 3, another test result of the orthophosphate concentration provided by the embodiment of the present invention is shown. As shown in Table 3, the relative error between the orthophosphate concentration measured by the on-line monitoring method for the orthophosphate concentration provided by the embodiment of the present invention and the actual orthophosphate concentration is less than 0.2 μg / l, indicating that when the orthophosphate concentration is less than 0.1 mg / l, the orthophosphate concentration measured by the on-line monitoring method for the orthophosphate concentration provided by the embodiment of the present invention has high accuracy and meets the requirements of the standard method.

[0155] Table 3

[0156]

[0157] Example 3

[0158] Using the method described in Example 2, the first test water sample and the second test water sample were respectively obtained from two rivers in Xi'an, and the orthophosphate concentrations in the first test water sample and the second test water sample were measured. The measurement results are shown in Table 4. The relative error between the orthophosphate concentration measured by the on-line monitoring method for the orthophosphate concentration provided by the embodiment of the present invention and the orthophosphate concentration measured by the method of using the national standard (GB / T 6913.4-93) and subsequent manual extraction is less than 0.9 μg / l, indicating that the on-line monitoring method for the orthophosphate concentration provided by the embodiment of the present invention has high accuracy and is suitable for detecting the orthophosphate concentration in water sources.

[0159] Table 4

[0160]

[0161] In summary, for the on-line monitoring method for orthophosphate concentration provided by the embodiments of the present invention, first, the first chip in the microfluidic chip assembly mixes the water sample to be measured and the detection reagent, and determines the first concentration of orthophosphate in the water sample to be measured based on the first absorbance value of the first mixed solution. When the first concentration is less than or equal to the first threshold, it indicates that the orthophosphate concentration in the water sample to be measured is relatively low, and there may be a large deviation in the first concentration determined by the first chip. In this case, the first chip transfers the first mixed solution to the second chip in the microfluidic chip assembly, so that the second chip can extract the first product in the first mixed solution to obtain a second mixed solution, and determine the second concentration of orthophosphate in the water sample to be measured based on the second absorbance value of the second mixed solution; when the orthophosphate concentration in the water sample to be measured is relatively low, the second chip extracts and enriches the first product in the first mixed solution, which increases the concentration of the first product in the second mixed solution, thereby improving the accuracy and sensitivity of the second concentration of orthophosphate in the water sample to be measured determined based on the second absorbance value of the second mixed solution; in addition, the detection reagent used in the embodiments of the present invention has a long shelf life and does not generate complexes to block the pipeline, and can operate automatically for a long time without human supervision, improving the automation degree of the process of detecting the orthophosphate concentration in the water sample to be measured and expanding the application range of the on-line monitoring method for orthophosphate concentration.

[0162] It should be noted that, for the method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the embodiments of the present invention are not limited by the described action sequence, because according to the embodiments of the present invention, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily essential to the embodiments of the present invention.

[0163] Device embodiments

[0164] Referring to Figure 6 , a structural block diagram of a microfluidic chip assembly provided by an embodiment of the present invention is shown. The microfluidic chip assembly includes a first chip and a second chip; the first chip and the second chip are connected;

[0165] The first chip 10 mixes the water sample to be measured and the detection reagent to obtain a first mixed solution; the detection reagent includes ammonium molybdate and ammonium metavanadate; the first mixed solution includes a first product, and the first product is obtained by the reaction of the water sample to be measured and the detection reagent; determines the first absorbance value of the first mixed solution, and determines the first concentration of orthophosphate in the water sample to be measured based on the first absorbance value; and when the first concentration is less than or equal to the first threshold, transfers the first mixed solution to the second chip;

[0166] The second chip 20 is configured to extract the first product in the first mixed solution to obtain a second mixed solution; the second mixed solution includes the first product and an extractant; determine a second absorbance value of the second mixed solution, and determine a second concentration of orthophosphate in the water sample to be measured based on the second absorbance value.

[0167] Optionally, the second chip has a second sample injection part, an extraction part, and a second detection part. The second sample injection part is connected to the inlet of the extraction part, and the outlet of the extraction part is connected to the second detection part.

[0168] The connection between the first chip and the second chip includes:

[0169] The second sample injection part is connected to the first chip.

[0170] The second chip is specifically configured to:

[0171] Inject the first mixed solution and the extractant into the extraction part by using the second sample injection part.

[0172] In the extraction part, use the extractant to extract the first product in the first mixed solution to obtain a second mixed solution.

[0173] Optionally, the extraction part includes a bent channel; the inlet of the channel is connected to the second sample injection part, and the outlet of the channel is connected to the second detection part.

[0174] Optionally, the second chip includes a bottom plate and a cover plate. The bottom plate has the second sample injection part, the extraction part, and the second detection part.

[0175] The channel includes a first sub-channel and a second sub-channel; the first sub-channel and the second sub-channel are separated from each other in a first area away from the cover plate, and the first sub-channel and the second sub-channel communicate with each other in a second area close to the cover plate; the first sub-channel is used to transport the first mixed solution, and the second sub-channel is used to transport the second mixed solution.

[0176] Optionally, in the extraction part, a first volume of the first mixed solution is M times a second volume of the extractant, and the value range of M is from 1 to 100.

[0177] Optionally, the first chip has a first sample injection part, a mixing and reaction part, and a first detection part. The first sample injection part is connected to the inlet of the mixing and reaction part, and the outlet of the mixing and reaction part is connected to the first detection part.

[0178] The connection between the first chip and the second chip includes:

[0179] The first detection unit is connected to the second chip;

[0180] The first chip is specifically configured to:

[0181] Inject the water sample to be measured and the detection reagent into the mixing and reaction unit by using the first sample injection unit;

[0182] Mix the water sample to be measured and the detection reagent by using the mixing and reaction unit to obtain a first mixed solution.

[0183] Optionally, the first chip is specifically configured to:

[0184] Determine the concentration of orthophosphate corresponding to the first absorbance value from a first calibration curve; the first calibration curve is used to indicate the one-to-one correspondence between the absorbance value and the orthophosphate concentration;

[0185] Determine the concentration of orthophosphate corresponding to the first absorbance value as the first concentration.

[0186] Optionally, the first chip is further configured to:

[0187] Mix a solution of orthophosphate with a first preset concentration and the detection reagent to obtain a third mixed solution;

[0188] Determine the third absorbance value of the third mixed solution;

[0189] Mix a solution of orthophosphate with a second preset concentration and the detection reagent to obtain a fourth mixed solution;

[0190] Determine the fourth absorbance value of the fourth mixed solution;

[0191] Generate a first calibration curve based on the third absorbance value, the fourth absorbance value, the first preset concentration, and the second preset concentration.

[0192] For the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple. For related parts, please refer to the partial description of the method embodiment.

[0193] Each embodiment in this specification is described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same and similar parts among the embodiments, please refer to each other.

[0194] The embodiment of the present invention further provides an electronic device, and the electronic device includes the microfluidic chip assembly as described above.

[0195] Each embodiment in this specification is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0196] Through the description of the above embodiments, those skilled in the art can clearly understand that the above method of the embodiment can be implemented by means of software plus a necessary general hardware platform. Of course, it can also be implemented by hardware. However, in many cases, the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, in essence, or the part that makes contributions to the prior art can be embodied in the form of a software product. The computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes several instructions to enable a terminal (which can be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in each embodiment of the present invention.

[0197] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the above specific embodiments. The above specific embodiments are merely illustrative rather than restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the purpose of the present invention and the scope protected by the claims. All of these are within the protection scope of the present invention.

Claims

1. An on-line monitoring method for the concentration of orthophosphate, characterized in that, Applied to a microfluidic chip component, the microfluidic chip component includes a first chip and a second chip, and the first chip is connected to the second chip; the method includes: The first chip mixes a water sample to be tested and a detection reagent to obtain a first mixed solution; the detection reagent includes ammonium molybdate and ammonium metavanadate; the first mixed solution includes a first product, and the first product is obtained by the reaction of the water sample to be tested and the detection reagent; The first chip determines a first absorbance value of the first mixed solution, and determines a first concentration of orthophosphate in the water sample to be tested based on the first absorbance value; When the first concentration is less than or equal to a first threshold, the first chip transfers the first mixed solution to the second chip; The second chip performs extraction treatment on the first product in the first mixed solution to obtain a second mixed solution; the second mixed solution includes the first product and an extractant; The second chip determines a second absorbance value of the second mixed solution, and determines a second concentration of orthophosphate in the water sample to be tested based on the second absorbance value.

2. The method according to claim 1, wherein The second chip has a second sample injection part, an extraction part and a second detection part, the second sample injection part is connected to the inlet of the extraction part, and the outlet of the extraction part is connected to the second detection part; The connection between the first chip and the second chip includes: The second sample injection part is connected to the first chip; The second chip performs extraction treatment on the first product in the first mixed solution to obtain a second mixed solution, including: The second chip injects the first mixed solution and the extractant into the extraction part by using the second sample injection part; The second chip performs extraction treatment on the first product in the first mixed solution by using the extractant in the extraction part to obtain a second mixed solution.

3. The method according to claim 2, wherein The extraction part includes a bent channel; the inlet of the channel is connected to the second sample injection part, and the outlet of the channel is connected to the second detection part.

4. The method according to claim 3, characterized in that The second chip includes a bottom plate and a cover plate, and the bottom plate has the second sample injection part, the extraction part and the second detection part; The channel includes a first sub-channel and a second sub-channel; the first sub-channel and the second sub-channel are separated from each other in a first area away from the cover plate, and the first sub-channel and the second sub-channel communicate with each other in a second area close to the cover plate; the first sub-channel is used to transport the first mixed solution, and the second sub-channel is used to transport the second mixed solution.

5. The method according to claim 2, characterized in that, In the extraction part, a first volume of the first mixed solution is M times a second volume of the extractant, and the value range of M is from 1 to 100.

6. The method according to claim 1, wherein The first chip has a first sample injection part, a mixing and reaction part and a first detection part, the first sample injection part is connected to the inlet of the mixing and reaction part, and the outlet of the mixing and reaction part is connected to the first detection part; The connection between the first chip and the second chip includes: The first detection part is connected to the second chip; The first chip mixes a water sample to be tested and a detection reagent to obtain a first mixed solution, including: The first chip injects the water sample to be measured and the detection reagent into the mixing and reaction part by using the first sample injection part; The first chip mixes the water sample to be measured and the detection reagent by using the mixing and reaction part to obtain a first mixed solution.

7. The method according to claim 1, characterized in that The first chip determines the first concentration of orthophosphate in the water sample to be measured based on the first absorbance value, including: The first chip determines the orthophosphate concentration corresponding to the first absorbance value from a first calibration curve according to the first absorbance value; the first calibration curve is used to indicate the one-to-one correspondence between the absorbance value and the orthophosphate concentration; The first chip determines the orthophosphate concentration corresponding to the first absorbance value as the first concentration.

8. The method according to claim 7, characterized in that, The method further includes: The first chip mixes a positive phosphate solution with a first preset concentration and the detection reagent to obtain a third mixed solution; The first chip determines the third absorbance value of the third mixed solution; The first chip mixes a positive phosphate solution with a second preset concentration and the detection reagent to obtain a fourth mixed solution; The first chip determines the fourth absorbance value of the fourth mixed solution; The first chip generates a first calibration curve based on the third absorbance value, the fourth absorbance value, the first preset concentration, and the second preset concentration.

9. A microfluidic chip component, characterized in that, The microfluidic chip assembly includes a first chip and a second chip, and the first chip and the second chip are connected; The first chip mixes the water sample to be measured and the detection reagent to obtain a first mixed solution; the detection reagent includes ammonium molybdate and ammonium metavanadate; The first mixed solution includes a first product, which is obtained by the reaction of the water sample to be measured and the detection reagent; determine the first absorbance value of the first mixed solution, and determine the first concentration of orthophosphate in the water sample to be measured based on the first absorbance value; and in the case where the first concentration is less than or equal to a first threshold, transfer the first mixed solution to the second chip; The second chip is used to perform extraction treatment on the first product in the first mixed solution to obtain a second mixed solution; The second mixed solution includes the first product and an extractant; Determine the second absorbance value of the second mixed solution, and determine the second concentration of orthophosphate in the water sample to be measured based on the second absorbance value.

10. An electronic device, characterized in that, The electronic device includes the microfluidic chip assembly according to claim 9.

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