Micro-reagent total phosphorus analyzer and analysis method

Abstract

The invention discloses a micro reagent total phosphorus analyzer and an analysis method, and belongs to the technical field of water quality monitoring. A liquid metering assembly comprises an injection pump, a liquid storage ring and a multi-channel valve; the digestion colorimetric assembly comprises a digestion tube, a heating element, a temperature sensor, a fan, a light source and a photodiode; the liquid discharge assembly comprises a peristaltic pump; a liquid outlet of the injection pump is connected with a first port of the liquid storage ring through the first electromagnetic pinch valve and the second electromagnetic pinch valve in sequence, a second port of the liquid storage ring is connected with a public port of the multi-channel valve, and a sample inlet of the digestion pipe is connected with a first channel of the multi-channel valve and the peristaltic pump through the first high-pressure two-way valve. The other channels of the multi-channel valve are respectively connected with the water sample to be detected, and a total phosphorus detection reagent and a total phosphorus standard solution which are used for carrying out total phosphorus analysis on the water sample to be detected. The micro-reagent total phosphorus analyzer provided by the invention can eliminate cross contamination of reagents, reduce reagent consumption and waste liquid amount, and improve metering precision and detection stability of micro-reagents.

Description

Technical Field

[0001] This invention relates to a micro-reagent total phosphorus analyzer and analytical method, belonging to the field of water quality monitoring technology. Background Technology

[0002] Total phosphorus concentration is an important parameter reflecting water quality. Total phosphorus is a key nutrient for the growth of aquatic plants and animals, especially algae. High total phosphorus levels can lead to eutrophication, causing algal blooms and blackening / odorization of water bodies. Total phosphorus is a mandatory water quality parameter for surface water, and online total phosphorus analyzers are increasingly widely used in environmental water quality testing.

[0003] Traditional total phosphorus analyzers are large in size and consume a lot of power. During operation, they consume a lot of reagents and generate a lot of waste liquid, resulting in a high frequency of instrument maintenance and a significant increase in maintenance costs. This makes them difficult to deploy on a large scale. In many places, due to high maintenance costs, existing automatic monitoring stations have reduced their operating frequency or have been forced to stop operating.

[0004] In terms of measuring the reagent volume of total phosphorus analyzers, most instruments use peristaltic pumps. However, the pump tubing in peristaltic pumps is prone to aging and deformation due to long-term rotation and compression, resulting in measurement errors.

[0005] In addition, potassium persulfate is used as an oxidizing agent during total phosphorus digestion, which has strong oxidizing properties. The sulfuric acid used is also highly corrosive, which will further shorten the service life of the pump tube, resulting in inaccurate reagent volume measurement and poor instrument measurement stability. Summary of the Invention

[0006] The purpose of this invention is to provide a microreactor total phosphorus analyzer and analytical method that can reduce reagent cross-contamination, reduce reagent consumption and waste liquid volume, and improve the metrological accuracy and detection stability of microreactors.

[0007] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a micro-reagent total phosphorus analyzer, comprising a liquid metering component, a digestion and colorimetric component, and a liquid discharge component connected by tubing; the liquid metering component includes an injection pump, a reservoir ring, and a multi-channel valve connected by tubing; the digestion and colorimetric component includes a digestion tube, a heating element disposed on the surface of the digestion tube, a temperature sensor disposed inside the digestion tube, a fan disposed outside the digestion tube, and a light source and a photodiode disposed on both sides of the digestion tube respectively; the liquid discharge component includes a peristaltic pump; the outlet of the injection pump is connected in sequence to the first port of the reservoir ring through the first port of a first electromagnetic clamp valve and the first port of a second electromagnetic clamp valve, the first electromagnetic clamp valve... The second port of the device is connected to the cleaning water, the second port of the second electromagnetic clamp valve is connected to the outside air, the second port of the liquid storage ring is connected to the common port of the multi-channel valve, the sample inlet of the digestion tube is connected to the first channel of the multi-channel valve and the first port of the peristaltic pump through the first high-pressure two-way valve, the second port of the peristaltic pump is connected to the cleaning water tank and the waste liquid tank through the first and second ports of the third electromagnetic clamp valve, and the other channels of the multi-channel valve are connected to the water sample to be tested and the total phosphorus detection reagent and the total phosphorus standard solution used for total phosphorus analysis of the water sample to be tested; all electrical components are connected to the control terminal signal, feed back signals to the control terminal and are controlled by the control terminal.

[0008] In conjunction with the first aspect, further, the outlet of the injection pump is connected to the first port and the second port of the first electromagnetic clamp valve through the first tee connector, the first port of the first electromagnetic clamp valve is connected to the first port and the second port of the second electromagnetic clamp valve through the second tee connector, the inlet of the digestion tube is connected to the first port of the first high-pressure two-way valve, the second port of the first high-pressure two-way valve is connected to the first channel of the multi-channel valve and the first port of the peristaltic pump through the third tee connector, and the second port of the peristaltic pump (31) is connected to the first port and the second port of the third electromagnetic clamp valve through the fourth tee connector.

[0009] In conjunction with the first aspect, furthermore, each tee is either a Y-type tee or a T-type tee.

[0010] In conjunction with the first aspect, furthermore, the digestion tube is a quartz digestion tube.

[0011] In addition to the first aspect, the digestion tube is also equipped with an overflow port, which is connected to the outside air through a second high-pressure two-way valve.

[0012] In conjunction with the first aspect, furthermore, the sample inlet is located at the bottom of the digestion tube, and the overflow outlet is located at the top of the digestion tube.

[0013] In conjunction with the first aspect, furthermore, the interfaces of each high-pressure two-way valve are made of polytetrafluoroethylene.

[0014] In conjunction with the first aspect, furthermore, the second, third, fourth, fifth, and sixth channels of the multi-channel valve are respectively connected to the water sample to be tested, the first total phosphorus detection reagent, the second total phosphorus detection reagent, the third total phosphorus detection reagent, and the total phosphorus standard solution; Each liter of the first total phosphorus test reagent contains 50g of potassium persulfate, which is then diluted to 500mL with a mixture of concentrated sulfuric acid and deionized water in a volume ratio of 1:1, and then diluted to 1L with water. Each liter of the second total phosphorus reagent contains 35g of ascorbic acid; Each liter of the third total phosphorus reagent contains 35g ammonium molybdate, 20g citric acid, 29mL of 25% ammonia water and 0.5g potassium antimony tartrate.

[0015] In a second aspect, the present invention provides a total phosphorus analysis method for a microreactor total phosphorus analyzer as described in the first aspect, comprising: Step 1: Inject the water sample to be tested into the digestion tube through a multi-channel valve, a liquid storage ring, and a syringe pump, and then drain the liquid in the digestion tube through a peristaltic pump; Step 2: The digestion reagent and the water sample to be tested in the total phosphorus detection reagent are injected into the digestion tube in sequence through the multi-channel valve, the liquid storage ring and the injection pump. Air is blown into the digestion tube by the peristaltic pump. Then, the liquid in the digestion tube is heated to the first preset temperature by the heating element and cooled to the second preset temperature by the fan. The first absorbance is calculated based on the light emitted by the light source and transmitted through the liquid in the digestion tube by the photodiode. Step 3: The colorimetric reagent in the total phosphorus detection reagent is injected into the digestion tube sequentially through the multi-channel valve, the liquid storage ring and the injection pump. Air is then blown into the digestion tube by the peristaltic pump. After the liquid in the digestion tube has reacted for a preset time, the second absorbance is calculated based on the light emitted by the light source and transmitted through the liquid in the digestion tube by the photodiode. Step 4: Calculate the total phosphorus absorbance based on the first and second absorbance, and calculate the total phosphorus concentration in the water sample based on the total phosphorus standard curve. Step 5: Empty the liquid in the digestion tube using a peristaltic pump, and inject cleaning water into the digestion tube using a multi-channel valve and a syringe pump, then empty the liquid in the digestion tube again using a peristaltic pump; Step 6: Inject cleaning water into the digestion tube through the multi-channel valve and injection pump, and drain the liquid in the digestion tube through the peristaltic pump. Then, inject air into the pipeline through the multi-channel valve and injection pump to purge the pipeline, and then reset all electrical components.

[0016] In conjunction with the second aspect, the total phosphorus absorbance is further as follows: ; in, Indicates total phosphorus absorbance. , These represent the first absorbance and the second absorbance, respectively. The total phosphorus standard curve is as follows: ; in, This indicates the concentration of total phosphorus. This represents the slope of the total phosphorus standard curve. This represents the intercept of the total phosphorus standard curve; Substituting the total phosphorus absorbance into the total phosphorus standard curve, the concentration of total phosphorus in the water sample was calculated as follows: .

[0017] Compared with the prior art, the beneficial effects of the present invention are: (1) The total phosphorus analyzer for micro reagents provided by the present invention is equipped with an injection pump, a liquid storage ring, a multi-channel valve and an electromagnetic clamp valve, which are used to measure the total phosphorus detection reagent and the water sample to be tested. It can realize high-precision automated measurement of the volume of micro reagents, greatly reduce the consumption of total phosphorus reagents and the amount of waste liquid generated, and the instrument operates stably and reliably, significantly reducing the maintenance cost in the later stage.

[0018] (2) The micro-reagent total phosphorus analyzer provided by the present invention realizes automatic separation of waste liquid and cleaning water through electromagnetic clamp valve, which can further reduce the amount of waste liquid.

[0019] (3) The micro-reagent total phosphorus analysis method provided by the present invention fully automates the steps of pipeline rinsing, reagent metering, colorimetric measurement, pipeline cleaning and purging, and can realize automatic, rapid and accurate analysis of total phosphorus concentration in the water environment.

[0020] (4) The micro-reagent total phosphorus analysis method provided by the present invention adopts dynamic turbidity compensation technology, which can reduce the interference of water sample color and turbidity on the total phosphorus detection results and improve the anti-interference ability of the instrument. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the microreactor total phosphorus analyzer provided in the embodiment of the present invention; In the diagram: 11. Injection pump; 12. Reservoir ring; 13. Multi-channel valve; 131. First channel; 132. Second channel; 133. Third channel; 134. Fourth channel; 135. Fifth channel; 136. Sixth channel; 137. Seventh channel; 138. Eighth channel; 139. Ninth channel; 1310. Tenth channel; 21. Digestion tube; 22. Heating element; 23. Temperature sensor; 24. Fan; 25. Light source; 26. Photodiode; 31. Peristaltic pump; 41. First electromagnetic clamp valve; 42. Second electromagnetic clamp valve; 43. Third electromagnetic clamp valve; 51. First high-pressure two-way valve; 52. Second high-pressure two-way valve; 61. First tee connector; 62. Second tee connector; 63. Third tee connector. Detailed Implementation

[0022] The technical solution of the present invention will be further described in detail below with reference to specific embodiments.

[0023] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Unless otherwise specified, embodiments of the present invention and the technical features thereof can be combined with each other.

[0024] This invention provides a microreactor total phosphorus analyzer, comprising a liquid metering component, a digestion colorimetric component, and a liquid discharge component connected by tubing.

[0025] In this embodiment, as Figure 1 As shown, the liquid metering assembly includes an injection pump 11, a liquid storage ring 12, and a multi-channel valve 13 connected by a pipeline; the digestion colorimetric assembly includes a digestion tube 21, a heating element 22 disposed on the surface of the digestion tube 21, a temperature sensor 23 disposed inside the digestion tube 21, a fan 24 disposed outside the digestion tube 21, and a light source 25 and a photodiode 26 disposed on both sides of the digestion tube 21 respectively; the liquid discharge assembly includes a peristaltic pump 31.

[0026] Specifically, such as Figure 1As shown, the outlet of the syringe pump 11 is connected to the first port of the storage ring 12 via the first port of the first electromagnetic clamp valve 41 and the first port of the second electromagnetic clamp valve 42. The second port of the first electromagnetic clamp valve 41 is connected to the cleaning water, and the second port of the second electromagnetic clamp valve 42 is connected to the outside air. The second port of the storage ring 12 is connected to the common port of the multi-channel valve 13. The inlet of the digestion tube 21 is connected to the first channel 131 of the multi-channel valve 13 and the first port of the peristaltic pump 31 via the first high-pressure two-way valve 51. The second port of the peristaltic pump 31 is connected to the cleaning water tank and the waste liquid tank via the first port and the second port of the third electromagnetic clamp valve 43, respectively. The other channels of the multi-channel valve 13 are connected to the water sample to be tested and the total phosphorus detection reagent and the total phosphorus standard solution used for total phosphorus analysis of the water sample to be tested.

[0027] Figure 1 In the diagram, 1 represents the first port of each electromagnetic clamp valve, and 2 represents the second port of each electromagnetic clamp valve.

[0028] In this embodiment, each electrical component is connected to the control terminal signal, feeds back signals to the control terminal, and is controlled by the control terminal.

[0029] The micro-reagent total phosphorus analyzer provided in this invention employs a design that combines a syringe pump 11, a reservoir ring 12, a multi-channel valve 13, and various electromagnetic clamp valves to measure the total phosphorus detection reagent and the water sample to be tested. This enables high-precision automated measurement of trace reagent volumes, significantly reducing the consumption of total phosphorus reagent and the amount of waste liquid generated. The instrument operates stably and reliably, significantly reducing subsequent maintenance costs. The automatic separation of waste liquid and cleaning water through the electromagnetic clamp valves further reduces the amount of waste liquid.

[0030] In one possible embodiment, such as Figure 1 As shown, the outlet of the syringe pump 11 is connected to the first port and the second port of the first electromagnetic clamp valve 41 through the first tee connector 61. The first port of the first electromagnetic clamp valve 41 is connected to the first port and the second port of the second electromagnetic clamp valve 42 through the second tee connector 62. The inlet of the digestion tube 21 is connected to the first port of the first high-pressure two-way valve 51. The second port of the first high-pressure two-way valve 51 is connected to the first channel 131 of the multi-channel valve 13 and the first port of the peristaltic pump 31 through the third tee connector 63. The second port of the peristaltic pump 31 is connected to the first port and the second port of the third electromagnetic clamp valve 43 through the fourth tee connector 64.

[0031] Specifically, such as Figure 1 As shown, each tee is either a Y-type tee or a T-type tee.

[0032] In one possible embodiment, the volume of the reservoir ring 12 is 10 mL to 20 mL.

[0033] In one possible embodiment, the digestion tube 21 is a quartz digestion tube, and the light source 25 is an LED light source.

[0034] Specifically, the LED light source has a power supply voltage of 2.0V to 2.2V and a typical emission wavelength of 710nm. The peak response wavelength of the photodiode 26 is 700nm. The light of a specific wavelength emitted by the LED light source is received by the photodiode 26 after passing through the desiccant 21. The photodiode 26 then converts the optical signal into an electrical signal for processing.

[0035] In one possible embodiment, the digestion tube 21 is also provided with an overflow port, which is connected to the outside air through a second high-pressure two-way valve 52.

[0036] Specifically, the sample inlet is located at the bottom of the digestion tube 21, and the overflow outlet is located at the top of the digestion tube 21.

[0037] In one possible embodiment, the interfaces of each high-pressure two-way valve are made of polytetrafluoroethylene (PTFE).

[0038] By blocking the inlet and overflow ports at both ends of the digestion tube 21 with a high-pressure two-way valve, a certain pressure is maintained inside the digestion tube 21 during total phosphorus digestion, thus promoting the digestion of total phosphorus.

[0039] In one possible embodiment, the multi-channel valve 13 is a ten-channel valve. The second channel 132, the third channel 133, the fourth channel 134, the fifth channel 135, and the sixth channel 136 of the ten-channel valve are respectively connected to the water sample to be tested, the first total phosphorus test reagent, the second total phosphorus test reagent, the third total phosphorus test reagent, and the total phosphorus standard solution. The seventh channel 137, the eighth channel 138, the ninth channel 139, and the tenth channel 1310 of the ten-channel valve are all spare channels.

[0040] Specifically, for the first total phosphorus test reagent: each liter of the first total phosphorus test reagent contains 50g of potassium persulfate, which is then diluted to 500mL with a 1:1 mixture of concentrated sulfuric acid and deionized water, and then diluted to 1L with water.

[0041] For the second total phosphorus test reagent: each liter of the second total phosphorus reagent contains 35g of ascorbic acid.

[0042] For the third total phosphorus test reagent: each liter of the third total phosphorus reagent contains 35g ammonium molybdate, 20g citric acid, 29mL of 25% ammonia water and 0.5g potassium antimony tartrate.

[0043] The micro-reagent total phosphorus analyzer provided in this invention has the advantages of accurate measurement, good stability, and miniaturization. It can solve the problems of high cost and maintenance cost of existing online total phosphorus analysis instruments, reagent measurement error caused by aging and deformation of pump tubes during peristaltic pump measurement, and large amount of reagent consumption and waste liquid generation. It provides a reliable guarantee for long-term accurate monitoring of total phosphorus in water quality.

[0044] This invention provides a total phosphorus analysis method using a microreactor total phosphorus analyzer as provided in this invention, comprising: Step 1: Pipeline flushing: The water sample to be tested is injected into the digestion tube 21 through the multi-channel valve 13, the liquid storage ring 12 and the injection pump 11, and then the liquid in the digestion tube 21 is emptied through the peristaltic pump 31. Step 2: The digestion reagent and the water sample to be tested in the total phosphorus detection reagent are sequentially injected into the digestion tube 21 through the multi-channel valve 13, the liquid storage ring 12 and the injection pump 11. Air is blown into the digestion tube 21 by the peristaltic pump 31. Then, the liquid in the digestion tube 21 is heated to the first preset temperature by the heating element 22 and cooled to the second preset temperature by the fan 24. The first absorbance is calculated based on the light emitted by the light source 25 and transmitted through the liquid in the digestion tube 21 by the photodiode 26. Step 3: The colorimetric reagent in the total phosphorus detection reagent is injected into the digestion tube 21 sequentially through the multi-channel valve 13, the liquid storage ring 12 and the injection pump 11. Air is blown into the digestion tube 21 through the peristaltic pump 31. After the liquid in the digestion tube 21 reacts for a preset time, the second absorbance is calculated based on the light emitted by the light source 25 and transmitted through the liquid in the digestion tube 21 by the photodiode 26. Step 4: Calculate the total phosphorus absorbance based on the first and second absorbance, and calculate the total phosphorus concentration in the water sample based on the total phosphorus standard curve. Step 5: Drain the liquid in the digestion tube 21 using the peristaltic pump 31, and inject cleaning water into the digestion tube 21 through the multi-channel valve 13 and the injection pump 11, and then drain the liquid in the digestion tube 21 again using the peristaltic pump 31. Step 6: Inject cleaning water into digestion tube 21 through multi-channel valve 13 and injection pump 11, and drain the liquid in digestion tube 21 through peristaltic pump 31. Then, inject air into the pipeline through multi-channel valve 13 and injection pump 11 to drain the pipeline, and then reset all electrical components.

[0045] The microreactor total phosphorus analysis method provided in this invention fully automates steps such as pipeline rinsing, reagent metering, colorimetric measurement, pipeline cleaning, and purging, enabling automatic, rapid, and accurate analysis of total phosphorus concentration in the aquatic environment. The use of dynamic turbidity compensation technology reduces the interference of water sample color and turbidity on the total phosphorus detection results, improving the instrument's anti-interference capability.

[0046] In one possible embodiment, the microreactor total phosphorus analyzer provided in this invention is described as follows: Each electromagnetic clamp valve is configured such that, when energized, the first port is open and the second port is closed, and when de-energized, the first port is closed and the second port is open.

[0047] The third electromagnetic clamp valve 43 is configured such that: the first port is connected to the cleaning water tank through a pipeline but does not contact the liquid in the cleaning water tank; the second port is connected to the waste liquid tank through a pipeline but does not contact the liquid in the waste liquid tank. When the peristaltic pump 31 rotates clockwise, the liquid is discharged into the cleaning water tank or waste liquid tank by controlling the third electromagnetic clamp valve 43 to be energized or de-energized. When the peristaltic pump 31 rotates counterclockwise, if the third electromagnetic clamp valve 43 is energized, air above the cleaning water tank is drawn into the pipeline through the first port of the third electromagnetic clamp valve 43. If the third electromagnetic clamp valve 43 is de-energized, air above the waste liquid tank is drawn into the pipeline through the second port of the third electromagnetic clamp valve 43.

[0048] The second channel 132, the third channel 133, the fourth channel 134, the fifth channel 135, and the sixth channel 136 of the multi-channel valve 13 are respectively connected to the water sample to be tested, the first total phosphorus detection reagent, the second total phosphorus detection reagent, the third total phosphorus detection reagent, and the total phosphorus standard solution.

[0049] The first total phosphorus test reagent is a digestion reagent. Each liter of the first total phosphorus test reagent contains 50g of potassium persulfate, which is then diluted to 500mL with a mixture of concentrated sulfuric acid and deionized water at a volume ratio of 1:1, and then diluted to 1L with water.

[0050] The second and third total phosphorus reagents are colorimetric reagents. Each liter of the second total phosphorus reagent contains 35g of ascorbic acid, and each liter of the third total phosphorus reagent contains 35g of ammonium molybdate, 20g of citric acid, 29mL of 25% ammonia water, and 0.5g of potassium antimony tartrate.

[0051] The general procedure for liquid measurement is as follows: first, draw the reagent (or water sample) and then blow 5 mL of air (the second electromagnetic clamp valve 42 is de-energized to draw air and energized to expel air), and finally, clean the reservoir ring with 2 mL of cleaning water (the first electromagnetic clamp valve 41 is de-energized to draw cleaning water into the syringe pump 11, and the first electromagnetic clamp valve 41 is energized to pump the cleaning water in the syringe pump 11 out of the reservoir ring 12).

[0052] In this embodiment, the total phosphorus analysis method specifically includes the following steps: Step 1: Pipeline flushing: The water sample to be tested is injected into the digestion tube 21 through the multi-channel valve 13, the liquid storage ring 12 and the injection pump 11, and then the liquid in the digestion tube 21 is emptied through the peristaltic pump 31. Specifically, the control terminal energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, controls the multi-channel valve 13 to switch to the second channel 132, controls the syringe pump 11 to draw a certain volume of water sample to be tested into the storage ring 12, controls the multi-channel valve 13 to switch to the first channel 131, controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to be conducted, controls the syringe pump 11 to inject the water sample to be tested from the storage ring 12 into the digestion tube 21, controls the third electromagnetic clamp valve 43 to energize, controls the peristaltic pump 31 to rotate clockwise, and drains the liquid in the digestion tube 21 into the cleaning water tank, completing the pipeline rinsing.

[0053] Step 2: Digestion reagent metering: The digestion reagent in the total phosphorus detection reagent is injected into the digestion tube 21 through the multi-channel valve 13, the liquid storage ring 12 and the syringe pump 11; Specifically, the control terminal energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, controls the multi-channel valve 13 to switch to the third channel 133, controls the syringe pump 11 to draw a certain volume of the first total phosphorus detection reagent into the storage ring 12, controls the multi-channel valve 13 to switch to the first channel 131, controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, and controls the syringe pump 11 to inject the first total phosphorus detection reagent in the storage ring 12 into the digestion tube 21, thus completing the digestion reagent metering.

[0054] Step 3: Measurement of water sample to be tested: The water sample to be tested is injected into the digestion tube 21 through the multi-channel valve 13, the liquid storage ring 12 and the injection pump 11; Specifically, the control terminal energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, controls the multi-channel valve 13 to switch to the second channel 132, controls the injection pump 11 to draw a certain volume of water sample to be tested into the storage ring 12, controls the multi-channel valve 13 to switch to the first channel 131, controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to be turned on, and controls the injection pump 11 to inject the water sample to be tested from the storage ring 12 into the digestion tube 21, thus completing the measurement of the water sample to be tested.

[0055] Step 4: Total phosphorus digestion: Air is blown into the digestion tube 21 by the peristaltic pump 31, the liquid in the digestion tube 21 is heated to the first preset temperature by the heating element 22, and the liquid in the digestion tube 21 is cooled to the second preset temperature by the fan 24. The first absorbance is calculated based on the light emitted by the light source 25 and transmitted through the liquid in the digestion tube 21 by the photodiode 26. Specifically, the control terminal controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, controls the peristaltic pump 31 to rotate counterclockwise, and blows air into the digestion tube 21 to make the liquid in the digestion tube 21 mix evenly. The control terminal controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to close. The temperature sensor 23 collects the temperature of the liquid in the digestion tube 21, controls the heating power supply 22 to turn on, and keeps the temperature of the liquid in the digestion tube 21 at about 120°C. After the preset time for the timed digestion reaction, the heating power supply 22 stops heating, controls the fan 24 to turn on, and keeps the temperature of the liquid in the digestion tube 21 at about 60°C. The light source 25 emits light of a specific wavelength, and the photodiode 26 receives the light that penetrates the liquid in the digestion tube 21, calculates the first absorbance as a blank value, and completes the total phosphorus digestion.

[0056] Step 5: Total phosphorus color development: The color development reagent in the total phosphorus detection reagent is injected into the digestion tube 21 sequentially through the multi-channel valve 13, the liquid storage ring 12 and the injection pump 11. Air is blown into the digestion tube 21 by the peristaltic pump 31. After the liquid in the digestion tube 21 reacts for a preset time, the second absorbance is calculated based on the light emitted by the light source 25 and transmitted through the liquid in the digestion tube 21 by the photodiode 26. Specifically, the control terminal energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, controls the multi-channel valve 13 to switch to the fourth channel 134, controls the syringe pump 11 to draw a certain volume of the second total phosphorus detection reagent into the storage ring 12, controls the multi-channel valve 13 to switch to the first channel 131, controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, controls the syringe pump 11 to inject the second total phosphorus detection reagent from the storage ring 12 into the digestion tube 21; controls the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42 to energize, controls the multi-channel valve 13 to switch to the fifth channel 135, controls the syringe pump 11 to draw a certain volume of the third total phosphorus detection reagent into the storage ring 12, controls the multi-channel... When valve 13 is switched to open the first channel 131, the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 are opened, and the syringe pump 11 is controlled to inject the third total phosphorus detection reagent in the storage ring 12 into the digestion tube 21. When the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 are opened, the peristaltic pump 31 is controlled to rotate counterclockwise to blow air into the digestion tube 21, so that the liquid in the digestion tube 21 is mixed evenly. The control terminal controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to close, so that the liquid in the digestion tube 21 undergoes a timed color reaction. After the preset time, the light source 25 is controlled to emit light of a specific wavelength, and the light penetrating the liquid in the digestion tube 21 is received by the photodiode 26. The second absorbance is calculated to complete the total phosphorus color development.

[0057] Step 6: Total phosphorus detection: Calculate the total phosphorus absorbance based on the first and second absorbance, and calculate the concentration of total phosphorus in the water sample based on the total phosphorus standard curve to complete the total phosphorus detection. Specifically, the total phosphorus absorbance is: ; in, Indicates total phosphorus absorbance. , These represent the first absorbance and the second absorbance, respectively.

[0058] The total phosphorus standard curve is as follows: ; in, This indicates the concentration of total phosphorus. This represents the slope of the total phosphorus standard curve. This represents the intercept of the total phosphorus standard curve.

[0059] Substituting the total phosphorus absorbance into the total phosphorus standard curve, the concentration of total phosphorus in the water sample was calculated as follows: .

[0060] Step 7: Draining the tubing: Drain the liquid in the digestion tube 21 using the peristaltic pump 31, and inject cleaning water into the digestion tube 21 through the multi-channel valve 13 and the injection pump 11, and then drain the liquid in the digestion tube 21 again using the peristaltic pump 31. Specifically, the control terminal controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to be turned on, controls the third electromagnetic clamp valve 43 to be de-energized, and controls the peristaltic pump 31 to rotate clockwise to drain the liquid in the digestion tube 21 into the waste liquid tank, thus completing the pipeline emptying.

[0061] Step 8: Pipeline cleaning: Inject cleaning water into digestion tube 21 through multi-channel valve 13 and injection pump 11, and drain the liquid in digestion tube 21 through peristaltic pump 31. Then, inject air into the pipeline through multi-channel valve 13 and injection pump 11 to drain the pipeline, and then reset all electrical components.

[0062] Specifically, the control terminal de-energizes the first electromagnetic clamp valve 41, controls the injection pump 11 to draw a certain volume of cleaning water, energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, controls the multi-channel valve 13 to switch to the first channel 131, controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, controls the injection pump 11 to inject the cleaning water into the digestion tube 21, energizes the third electromagnetic clamp valve 43, and controls the peristaltic pump 31 to rotate clockwise, thus opening the digestion tube 21. The liquid in the tubing is drained into the cleaning water tank. The first electromagnetic clamp valve 41 is energized, the second electromagnetic clamp valve 42 is de-energized, the injection pump 11 is pumped out, the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42 are energized, the multi-channel valve 13 is switched to the first channel 131, the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 are opened, the injection pump 11 is injected into the digestion tube 21 to drain the tubing, and all electrical components are reset to complete the tubing cleaning.

[0063] To verify the effectiveness of the microreactor total phosphorus analyzer and analytical method provided in the embodiments of the present invention, the following experiments were conducted: (1) Micro-reagent metrological stability test: The densities of the first total phosphorus test reagent R1, the second total phosphorus test reagent R2, and the third total phosphorus test reagent R3 were measured in advance as follows: ρ1=0.9956g / mL, ρ2=0.9948g / mL, and ρ3=0.9963g / mL, respectively.

[0064] Before the experiment, fill the corresponding injection tubing with reagent, and then perform the measurement according to the following steps: Using a multi-channel valve 13, a liquid storage ring 12, and a syringe pump 11, 0.1 mL of the first total phosphorus test reagent R1, the second total phosphorus test reagent R2, and the third total phosphorus test reagent R3 were drawn into 5 mL centrifuge tubes respectively. The mass was weighed using an electronic balance and converted into the corresponding volume. The measurement was repeated three times, and the reagent measurement test results are shown in Table 1.

[0065] Table 1: Results of Reagent Volume Measurement Test .

[0066] As shown in Table 1, the standard deviation of the total phosphorus detection reagents R1, R2 and R3 in 100 μL is within 0.8, and the relative standard deviation is no more than ±1%, indicating that the reagent measurement is very stable.

[0067] (2) Water sample measurement stability test: The density of the water sample was measured beforehand as ρ = 1.0056 g / mL.

[0068] Before the test, fill the corresponding inlet pipe with the water sample to be tested, and then perform the measurement according to the following steps: 1 mL and 3 mL of water samples were drawn into 5 mL centrifuge tubes through a multi-channel valve 13, a liquid storage ring 12, and a syringe pump 11. The mass was measured using an electronic balance and converted into the corresponding volume. The measurement was repeated three times, and the water sample measurement results are shown in Table 2.

[0069] Table 2: Results of Water Sample Volume Measurement Test .

[0070] As shown in Table 2, the standard deviation of the 1 mL and 3 mL water sample measurements is within 0.05, and the relative standard deviation is no more than ±1.5%, indicating that the water sample measurement is very stable.

[0071] As can be seen from the above experiments, the total phosphorus analysis method using microreactors provided in this embodiment of the invention has excellent consistency in measurement, whether for reagents or water samples, and is the basis for realizing the miniaturization and microreactor of total phosphorus.

[0072] In one possible embodiment, the microreactor total phosphorus analyzer was calibrated using total phosphorus standard solutions of different concentrations, and the resulting total phosphorus standard curve was: .

[0073] The total phosphorus standard curve is input into the control terminal, which can call up the total phosphorus standard curve in real time when calculating the concentration of total phosphorus in the water sample.

[0074] Based on this total phosphorus standard curve, the following total phosphorus detection experiments were conducted: (1) Turbidity interference experiment: A total phosphorus standard solution with a turbidity of 300 NTU (total phosphorus concentration of 1 mg / L) was prepared using a turbidity standard solution, and then the following steps were taken for testing: Step 1: Pipeline flushing: The control terminal energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, controls the multi-channel valve 13 to switch to the second channel 132, controls the syringe pump 11 to draw 5 mL of total phosphorus standard solution into the storage ring 12, controls the multi-channel valve 13 to switch to the first channel 131, controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, controls the syringe pump 11 to inject the total phosphorus standard solution in the storage ring 12 into the digestion tube 21, controls the third electromagnetic clamp valve 43 to energize, controls the peristaltic pump 31 to rotate clockwise, and drains the liquid in the digestion tube 21 into the cleaning water tank, completing the pipeline rinsing.

[0075] Step 2: Digestion reagent dosage: The control terminal energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, controls the multi-channel valve 13 to switch to the third channel 133, controls the syringe pump 11 to draw 0.1 mL of the first total phosphorus detection reagent into the storage ring 12, controls the multi-channel valve 13 to switch to the first channel 131, controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, and controls the syringe pump 11 to inject the first total phosphorus detection reagent in the storage ring 12 into the digestion tube 21, thus completing the digestion reagent metering.

[0076] Step 3: Measurement of total phosphorus standard solution: The control terminal energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, controls the multi-channel valve 13 to switch to the second channel 132, controls the syringe pump 11 to draw 3 mL of total phosphorus standard solution into the storage ring 12, controls the multi-channel valve 13 to switch to the first channel 131, controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, and controls the syringe pump 11 to inject the total phosphorus standard solution in the storage ring 12 into the digestion tube 21, thus completing the measurement of total phosphorus standard solution.

[0077] Step 4: Total phosphorus digestion: The control terminal controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, controls the peristaltic pump 31 to rotate counterclockwise, and blows air into the digestion tube 21 for 10 seconds to make the liquid in the digestion tube 21 mix evenly. The control terminal then controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to close. The temperature sensor 23 collects the temperature of the liquid in the digestion tube 21, and controls the heating power supply 22 to turn on the heating to keep the temperature of the liquid in the digestion tube 21 at about 120°C. After the timed digestion reaction for 15 minutes, the heating power supply 22 is turned off, and the fan 24 is turned on to keep the temperature of the liquid in the digestion tube 21 at about 60°C. The light source 25 emits light of a specific wavelength, and the photodiode 26 receives the light that penetrates the liquid in the digestion tube 21. The first absorbance is calculated to be 0.0560, which is used as a blank value to complete the total phosphorus digestion.

[0078] Step 5: Total phosphorus color development: The control terminal energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, switches the multi-channel valve 13 to the fourth channel 134, and controls the syringe pump 11 to draw 0.1 mL of the second total phosphorus test reagent into the reservoir ring 12. It then switches the multi-channel valve 13 to the first channel 131, and controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to inject the second total phosphorus test reagent from the reservoir ring 12 into the digestion tube 21. Finally, it energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, switches the multi-channel valve 13 to the fifth channel 135, and controls the syringe pump 11 to draw 0.1 mL of the third total phosphorus test reagent into the reservoir ring 12. The multi-channel valve 13 then switches to the fifth channel 135. When the first channel 131 is open, the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 are opened, and the injection pump 11 is controlled to inject the third total phosphorus detection reagent in the storage ring 12 into the digestion tube 21. When the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 are opened, the peristaltic pump 31 is controlled to rotate counterclockwise to blow air into the digestion tube 21 for 15 seconds, so that the liquid in the digestion tube 21 is mixed evenly. The control terminal controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to close, so that the liquid in the digestion tube 21 undergoes a timed color development reaction for 4 minutes. Then, the light source 25 is controlled to emit light of a specific wavelength, and the light penetrating the liquid in the digestion tube 21 is received by the photodiode 26. The second absorbance is calculated to be 0.2085, and the total phosphorus color development is completed.

[0079] Step 6: Total Phosphorus Detection: Based on the first and second absorbance values, the total phosphorus absorbance was calculated to be 0.2085 - 0.0560 = 0.1525. Based on the total phosphorus standard curve, the concentration of total phosphorus in the total phosphorus standard solution was calculated to be (0.1525 + 0.0538) / 0.2248 mg / L = 0.9177 mg / L, with a relative error of -8.23%. The total phosphorus detection was thus completed. Step 7: Drain the pipes: The control terminal controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, controls the third electromagnetic clamp valve 43 to de-energize, and controls the peristaltic pump 31 to rotate clockwise, emptying the liquid in the digestion tube 21 into the waste liquid tank, thus completing the pipeline emptying.

[0080] Step 8: Pipeline cleaning: The control terminal de-energizes the first electromagnetic clamp valve 41, controls the syringe pump 11 to draw 3 mL of cleaning water, energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, controls the multi-channel valve 13 to switch to the first channel 131, controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, controls the syringe pump 11 to inject cleaning water into the digestion tube 21, energizes the third electromagnetic clamp valve 43, controls the peristaltic pump 31 to rotate clockwise, and drains the liquid from the digestion tube 21. Empty the cleaning water tank, energize the first electromagnetic clamp valve 41, de-energize the second electromagnetic clamp valve 42, control the injection pump 11 to draw 5mL of air, energize the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, control the multi-channel valve 13 to switch to the first channel 131, control the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, control the injection pump 11 to inject air into the digestion tube 21 to empty the pipeline, control all electrical components to reset, and complete the pipeline cleaning.

[0081] If turbidity compensation is not performed and only the absorbance of the colorimetric solution is measured, the concentration of total phosphorus in the total phosphorus standard solution is (0.2645+0.0538) / 0.2248mg / L=1.4159mg / L, with a relative error of 41.59%. The measured value is significantly larger than expected, indicating that even when the turbidity reaches 300NTU, this embodiment can still accurately measure the concentration of total phosphorus.

[0082] (2) Experiment for detecting the concentration of total phosphorus in wastewater: Step 1: Pipeline flushing: The control terminal energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, controls the multi-channel valve 13 to switch to the second channel 132, controls the syringe pump 11 to draw 5 mL of wastewater sample into the storage ring 12, controls the multi-channel valve 13 to switch to the first channel 131, controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, controls the syringe pump 11 to inject the wastewater sample in the storage ring 12 into the digestion tube 21, controls the third electromagnetic clamp valve 43 to energize, controls the peristaltic pump 31 to rotate clockwise, and drains the liquid in the digestion tube 21 into the cleaning water tank, completing the pipeline rinsing.

[0083] Step 2: Digestion reagent dosage: The control terminal energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, controls the multi-channel valve 13 to switch to the third channel 133, controls the syringe pump 11 to draw 0.1 mL of the first total phosphorus detection reagent into the storage ring 12, controls the multi-channel valve 13 to switch to the first channel 131, controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, and controls the syringe pump 11 to inject the first total phosphorus detection reagent in the storage ring 12 into the digestion tube 21, thus completing the digestion reagent metering.

[0084] Step 3: Wastewater sample measurement: The control terminal energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, controls the multi-channel valve 13 to switch to the second channel 132, controls the syringe pump 11 to draw 3 mL of wastewater sample into the storage ring 12, controls the multi-channel valve 13 to switch to the first channel 131, controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, and controls the syringe pump 11 to inject the wastewater sample in the storage ring 12 into the digestion tube 21, thus completing the wastewater sample metering.

[0085] Step 4: Total phosphorus digestion: The control terminal controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, controls the peristaltic pump 31 to rotate counterclockwise, and blows air into the digestion tube 21 for 10 seconds to make the liquid in the digestion tube 21 mix evenly. The control terminal then controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to close. The temperature sensor 23 collects the temperature of the liquid in the digestion tube 21, and controls the heating power supply 22 to turn on the heating to keep the temperature of the liquid in the digestion tube 21 at about 120°C. After the timed digestion reaction for 15 minutes, the heating power supply 22 is turned off, and the fan 24 is turned on to keep the temperature of the liquid in the digestion tube 21 at about 60°C. The light source 25 emits light of a specific wavelength, and the photodiode 26 receives the light that penetrates the liquid in the digestion tube 21. The first absorbance is calculated to be 0.0012, which is used as a blank value to complete the total phosphorus digestion.

[0086] Step 5: Total phosphorus color development: The control terminal energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, switches the multi-channel valve 13 to the fourth channel 134, and controls the syringe pump 11 to draw 0.1 mL of the second total phosphorus test reagent into the reservoir ring 12. It then switches the multi-channel valve 13 to the first channel 131, and controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to inject the second total phosphorus test reagent from the reservoir ring 12 into the digestion tube 21. Finally, it energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, switches the multi-channel valve 13 to the fifth channel 135, and controls the syringe pump 11 to draw 0.1 mL of the third total phosphorus test reagent into the reservoir ring 12. The multi-channel valve 13 then switches to the fifth channel 135. When the first channel 131 is open, the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 are opened, and the syringe pump 11 is controlled to inject the third total phosphorus detection reagent in the storage ring 12 into the digestion tube 21. When the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 are opened, the peristaltic pump 31 is controlled to rotate counterclockwise to blow air into the digestion tube 21 for 15 seconds, so that the liquid in the digestion tube 21 is mixed evenly. The control terminal controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to close, so that the liquid in the digestion tube 21 undergoes a timed color development reaction for 4 minutes. Then, the light source 25 is controlled to emit light of a specific wavelength, and the light penetrating the liquid in the digestion tube 21 is received by the photodiode 26. The second absorbance is calculated to be 0.1025, and the total phosphorus color development is completed.

[0087] Step 6: Total Phosphorus Detection: Based on the first and second absorbance values, the total phosphorus absorbance was calculated to be 0.1025 - 0.0012 = 0.1013. Based on the total phosphorus standard curve, the concentration of total phosphorus in the wastewater sample was calculated as (0.1013 + 0.0538) / 0.2248 mg / L = 0.6899 mg / L. The concentration of total phosphorus in the wastewater sample was measured manually in the laboratory to be 0.7025 mg / L, with a relative error of -1.79%. The total phosphorus detection was thus completed. Step 7: Drain the pipes: The control terminal controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, controls the third electromagnetic clamp valve 43 to de-energize, and controls the peristaltic pump 31 to rotate clockwise, emptying the liquid in the digestion tube 21 into the waste liquid tank, thus completing the pipeline emptying.

[0088] Step 8: Pipeline cleaning: The control terminal de-energizes the first electromagnetic clamp valve 41, controls the syringe pump 11 to draw 3 mL of cleaning water, energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, controls the multi-channel valve 13 to switch to the first channel 131, controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, controls the syringe pump 11 to inject cleaning water into the digestion tube 21, energizes the third electromagnetic clamp valve 43, controls the peristaltic pump 31 to rotate clockwise, and drains the liquid from the digestion tube 21. Empty the cleaning water tank, energize the first electromagnetic clamp valve 41, de-energize the second electromagnetic clamp valve 42, control the injection pump 11 to draw 5mL of air, energize the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, control the multi-channel valve 13 to switch to the first channel 131, control the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, control the injection pump 11 to inject air into the digestion tube 21 to empty the pipeline, control all electrical components to reset, and complete the pipeline cleaning.

[0089] (3) Experiment to detect the concentration of total phosphorus in river water: Step 1: Pipeline flushing: The control terminal energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, controls the multi-channel valve 13 to switch to the second channel 132, controls the syringe pump 11 to draw 5 mL of river water sample into the storage ring 12, controls the multi-channel valve 13 to switch to the first channel 131, controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, controls the syringe pump 11 to inject the river water sample in the storage ring 12 into the digestion tube 21, controls the third electromagnetic clamp valve 43 to energize, controls the peristaltic pump 31 to rotate clockwise, and drains the liquid in the digestion tube 21 into the cleaning water tank, completing the pipeline rinsing.

[0090] Step 2: Digestion reagent dosage: The control terminal energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, controls the multi-channel valve 13 to switch to the third channel 133, controls the syringe pump 11 to draw 0.1 mL of the first total phosphorus detection reagent into the storage ring 12, controls the multi-channel valve 13 to switch to the first channel 131, controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, and controls the syringe pump 11 to inject the first total phosphorus detection reagent in the storage ring 12 into the digestion tube 21, thus completing the digestion reagent metering.

[0091] Step 3: River water sample measurement: The control terminal energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, controls the multi-channel valve 13 to switch to the second channel 132, controls the syringe pump 11 to draw 3 mL of river water sample into the storage ring 12, controls the multi-channel valve 13 to switch to the first channel 131, controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, and controls the syringe pump 11 to inject the river water sample in the storage ring 12 into the digestion tube 21, thus completing the river water sample measurement.

[0092] Step 4: Total phosphorus digestion: The control terminal controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, controls the peristaltic pump 31 to rotate counterclockwise, and blows air into the digestion tube 21 for 10 seconds to make the liquid in the digestion tube 21 mix evenly. The control terminal then controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to close. The temperature sensor 23 collects the temperature of the liquid in the digestion tube 21, and controls the heating power supply 22 to turn on the heating to keep the temperature of the liquid in the digestion tube 21 at about 120°C. After the timed digestion reaction for 15 minutes, the heating power supply 22 is turned off, and the fan 24 is turned on to keep the temperature of the liquid in the digestion tube 21 at about 60°C. The light source 25 emits light of a specific wavelength, and the photodiode 26 receives the light that penetrates the liquid in the digestion tube 21. The first absorbance is calculated to be 0.0014, which is used as a blank value to complete the total phosphorus digestion.

[0093] Step 5: Total phosphorus color development: The control terminal energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, switches the multi-channel valve 13 to the fourth channel 134, and controls the syringe pump 11 to draw 0.1 mL of the second total phosphorus test reagent into the reservoir ring 12. It then switches the multi-channel valve 13 to the first channel 131, and controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to inject the second total phosphorus test reagent from the reservoir ring 12 into the digestion tube 21. Finally, it energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, switches the multi-channel valve 13 to the fifth channel 135, and controls the syringe pump 11 to draw 0.1 mL of the third total phosphorus test reagent into the reservoir ring 12. The multi-channel valve 13 then switches to the fifth channel 135. When the first channel 131 is open, the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 are opened, and the injection pump 11 is controlled to inject the third total phosphorus detection reagent in the storage ring 12 into the digestion tube 21. When the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 are opened, the peristaltic pump 31 is controlled to rotate counterclockwise to blow air into the digestion tube 21 for 15 seconds, so that the liquid in the digestion tube 21 is mixed evenly. The control terminal controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to close, so that the liquid in the digestion tube 21 undergoes a timed color development reaction for 4 minutes. Then, the light source 25 is controlled to emit light of a specific wavelength, and the light penetrating the liquid in the digestion tube 21 is received by the photodiode 26. The second absorbance is calculated to be 0.0409, and the total phosphorus color development is completed.

[0094] Step 6: Total Phosphorus Detection: Based on the first and second absorbance values, the total phosphorus absorbance was calculated to be 0.0409 - 0.0014 = 0.0395. Based on the total phosphorus standard curve, the total phosphorus concentration in the river water sample was calculated as (0.0395 + 0.0538) / 0.2248 mg / L = 0.4150 mg / L. The national standard method was used to determine the total phosphorus concentration in the river water sample. Three measurements of the same river water sample yielded an average total phosphorus concentration of 0.4382 mg / L, with a relative error of 5.29%. The total phosphorus detection was thus completed. Step 7: Drain the pipes: The control terminal controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, controls the third electromagnetic clamp valve 43 to de-energize, and controls the peristaltic pump 31 to rotate clockwise, emptying the liquid in the digestion tube 21 into the waste liquid tank, thus completing the pipeline emptying.

[0095] Step 8: Pipeline cleaning: The control terminal de-energizes the first electromagnetic clamp valve 41, controls the syringe pump 11 to draw 3 mL of cleaning water, energizes the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, controls the multi-channel valve 13 to switch to the first channel 131, controls the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, controls the syringe pump 11 to inject cleaning water into the digestion tube 21, energizes the third electromagnetic clamp valve 43, controls the peristaltic pump 31 to rotate clockwise, and drains the liquid from the digestion tube 21. Empty the cleaning water tank, energize the first electromagnetic clamp valve 41, de-energize the second electromagnetic clamp valve 42, control the injection pump 11 to draw 5mL of air, energize the first electromagnetic clamp valve 41 and the second electromagnetic clamp valve 42, control the multi-channel valve 13 to switch to the first channel 131, control the first high-pressure two-way valve 51 and the second high-pressure two-way valve 52 to open, control the injection pump 11 to inject air into the digestion tube 21 to empty the pipeline, control all electrical components to reset, and complete the pipeline cleaning.

[0096] The above experiments show that even when the turbidity reaches 300 NTU, the microreactor total phosphorus analysis method provided in this embodiment of the invention can still accurately measure the total phosphorus content. Test data from actual wastewater and river water samples show that the relative error of the total phosphorus measurement meets the error requirements stipulated in current standards. Therefore, the microreactor total phosphorus analysis method provided in this embodiment of the invention can accurately and reliably measure the total phosphorus concentration.

[0097] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A micro-reagent total phosphorus analyzer, characterized in that, The system includes a liquid metering assembly, a digestion and colorimetric assembly, and a liquid discharge assembly connected by pipelines. The liquid metering assembly includes an injection pump (11), a reservoir ring (12), and a multi-channel valve (13) connected by pipelines. The digestion and colorimetric assembly includes a digestion tube (21), a heating element (22) on the surface of the digestion tube (21), a temperature sensor (23) inside the digestion tube (21), a fan (24) outside the digestion tube (21), and a light source (25) and a photodiode (26) respectively located on both sides of the digestion tube (21). The liquid discharge assembly includes a peristaltic pump (31). The outlet of the injection pump (11) is connected to the first port of the reservoir ring (12) in sequence through the first port of the first electromagnetic clamp valve (41) and the first port of the second electromagnetic clamp valve (42). The second port of valve (41) is connected to the cleaning water, the second port of the second electromagnetic clamp valve (42) is connected to the outside air, the second port of the liquid storage ring (12) is connected to the common port of the multi-channel valve (13), the sample inlet of the digestion tube (21) is connected to the first channel (131) of the multi-channel valve (13) and the first port of the peristaltic pump (31) through the first high-pressure two-way valve (51), the second port of the peristaltic pump (31) is connected to the cleaning water tank and the waste liquid tank through the first port and the second port of the third electromagnetic clamp valve (43), and the other channels of the multi-channel valve (13) are connected to the water sample to be tested and the total phosphorus detection reagent and the total phosphorus standard solution used for total phosphorus analysis of the water sample to be tested; wherein, each electrical component is connected to the control terminal signal, feeds back signals to the control terminal and is controlled by the control terminal.

2. The microreactor total phosphorus analyzer according to claim 1, characterized in that, The outlet of the syringe pump (11) is connected to the first port and the second port of the first electromagnetic clamp valve (41) through the first three-way connector (61). The first port of the first electromagnetic clamp valve (41) is connected to the first port and the second port of the second electromagnetic clamp valve (42) through the second three-way connector (62). The inlet of the digestion tube (21) is connected to the first port of the first high-pressure two-way valve (51). The second port of the first high-pressure two-way valve (51) is connected to the first channel (131) of the multi-channel valve (13) and the first port of the peristaltic pump (31) through the third three-way connector (63). The second port of the peristaltic pump (31) is connected to the first port and the second port of the third electromagnetic clamp valve (43) through the fourth three-way connector (64).

3. The microreactor total phosphorus analyzer according to claim 2, characterized in that, Each tee is either a Y-type tee or a T-type tee.

4. The microreactor total phosphorus analyzer according to claim 1, characterized in that, The digestion tube (21) is a quartz digestion tube.

5. The microreactor total phosphorus analyzer according to claim 1, characterized in that, The digestion tube (21) is also equipped with an overflow port, which is connected to the outside air through a second high-pressure two-way valve (52).

6. The microreactor total phosphorus analyzer according to claim 5, characterized in that, The sample inlet is located at the bottom of the digestion tube (21), and the overflow outlet is located at the top of the digestion tube (21).

7. The microreactor total phosphorus analyzer according to claim 5, characterized in that, The interfaces of each high-pressure two-way valve are made of polytetrafluoroethylene.

8. The microreactor total phosphorus analyzer according to claim 1, characterized in that, The second channel (132), third channel (133), fourth channel (134), fifth channel (135), and sixth channel (136) of the multi-channel valve (13) are respectively connected to the water sample to be tested, the first total phosphorus test reagent, the second total phosphorus test reagent, the third total phosphorus test reagent, and the total phosphorus standard solution; Each liter of the first total phosphorus test reagent contains 50g of potassium persulfate, which is then diluted to 500mL with a mixture of concentrated sulfuric acid and deionized water in a volume ratio of 1:1, and then diluted to 1L with water. Each liter of the second total phosphorus reagent contains 35g of ascorbic acid; Each liter of the third total phosphorus reagent contains 35g ammonium molybdate, 20g citric acid, 29mL of 25% ammonia water and 0.5g potassium antimony tartrate.

9. A total phosphorus analysis method using a microreactor total phosphorus analyzer as described in any one of claims 1 to 8, characterized in that, include: Step 1: The water sample to be tested is injected into the digestion tube (21) through the multi-channel valve (13), the liquid storage ring (12) and the injection pump (11), and then the liquid in the digestion tube (21) is emptied through the peristaltic pump (31); Step 2: The digestion reagent and the water sample to be tested in the total phosphorus detection reagent are injected into the digestion tube (21) in sequence through the multi-channel valve (13), the liquid storage ring (12) and the injection pump (11). Air is blown into the digestion tube (21) by the peristaltic pump (31). Then, the liquid in the digestion tube (21) is heated to the first preset temperature by the heating element (22). The liquid in the digestion tube (21) is cooled to the second preset temperature by the fan (24). The first absorbance is calculated based on the light emitted by the light source (25) and transmitted through the liquid in the digestion tube (21) by the photodiode (26). Step 3: The colorimetric reagent in the total phosphorus detection reagent is injected into the digestion tube (21) sequentially through the multi-channel valve (13), the liquid storage ring (12) and the injection pump (11), and air is blown into the digestion tube (21) by the peristaltic pump (31). After the liquid in the digestion tube (21) reacts for a preset time, the second absorbance is calculated based on the light emitted by the light source (25) and transmitted through the liquid in the digestion tube (21) by the photodiode (26). Step 4: Calculate the total phosphorus absorbance based on the first and second absorbance, and calculate the total phosphorus concentration in the water sample based on the total phosphorus standard curve. Step 5: Drain the liquid in the digestion tube (21) using a peristaltic pump (31), and inject cleaning water into the digestion tube (21) using a multi-channel valve (13) and a syringe pump (11), and then drain the liquid in the digestion tube (21) again using a peristaltic pump (31); Step 6: Inject cleaning water into the digestion tube (21) through the multi-channel valve (13) and the injection pump (11), and drain the liquid in the digestion tube (21) through the peristaltic pump (31). Then, inject air into the pipeline through the multi-channel valve (13) and the injection pump (11) to drain the pipeline, and then reset each electrical component.

10. The total phosphorus analysis method according to claim 9, characterized in that, The total phosphorus absorbance is: ； in, Indicates total phosphorus absorbance. , These represent the first absorbance and the second absorbance, respectively. The total phosphorus standard curve is as follows: ； in, This indicates the concentration of total phosphorus. This represents the slope of the total phosphorus standard curve. This represents the intercept of the total phosphorus standard curve; Substituting the total phosphorus absorbance into the total phosphorus standard curve, the concentration of total phosphorus in the water sample was calculated as follows: 。

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