A micro-reagent ammonia nitrogen online continuous analyzer and analysis method

Abstract

The invention discloses a micro-reagent ammonia nitrogen online continuous analyzer and an analysis method, which belongs to the field of water quality ammonia nitrogen monitoring technology. The micro-reagent ammonia nitrogen online continuous analyzer includes a first syringe pump, a second syringe pump, a multichannel valve, a liquid storage ring and a reaction cell; the liquid outlets of the first syringe pump and the second syringe pump are connected to one end of the liquid storage ring and the circulation port of the reaction cell through different channels of the multichannel valve respectively; the circulation port of the reaction cell is connected with a first peristaltic pump; the other end of the liquid storage ring is connected with a second peristaltic pump; the liquid outlets of the first syringe pump and the second syringe pump are connected with a third peristaltic pump; the first syringe pump and the second syringe pump are respectively provided with a first reagent and a second reagent for ammonia nitrogen analysis; the different channels of the multichannel valve are respectively connected with a standard sample and a water sample for ammonia nitrogen analysis, and cleaning water. The micro-reagent ammonia nitrogen online continuous analyzer provided by the present invention can reduce reagent cross contamination, reduce reagent consumption, and can also realize short-interval continuous analysis.

Description

Technical Field

[0001] The invention relates to a micro-reagent ammonia nitrogen online continuous analyzer and an analysis method, belonging to the technical field of water quality ammonia nitrogen monitoring. Background Art

[0002] Ammonia nitrogen is one of the important indicator factors of river basin pollution, usually referring to NH3 and NH4 + Two forms of nitrogen. Ammonia nitrogen monitoring in water quality is an important means of carrying out water quality monitoring and building water quality early warning.

[0003] Mainstream methods for monitoring ammonia nitrogen in surface water include electrode detection, Nessler's reagent spectrophotometry, and salicylic acid spectrophotometry. In the salicylic acid spectrophotometry, ammonia and ammonium ions react with salicylate and hypochlorite ions to form a blue complex. The absorbance at 697 nm is proportional to the ammonia nitrogen content, providing water quality ammonia nitrogen data. This method is sensitive, stable, and easy to use in the laboratory, and has recently become widely used in automated water quality monitoring equipment.

[0004] On the one hand, existing ammonia nitrogen online analyzers generally have problems such as large sample volume, reagent consumption, and waste liquid discharge, which can easily cause secondary pollution and are not conducive to environmental protection and the deployment of large-scale grid water quality monitoring.

[0005] On the other hand, existing analyzers must complete the entire process of the first group of water samples, from sampling, reagent metering, sample injection and mixing to reaction, measurement, emptying and cleaning, before they can start measuring the second group of water samples from the beginning. The time interval is long and the analysis efficiency is low, which is not enough to meet the monitoring needs of rapid changes in water quality in a short period of time.

[0006] Sequential injection analysis (SIA) consists of a multi-state selector valve, a bidirectional injection pump, a liquid storage loop, and other fluid lines. Compared to traditional flow injection analysis (FIA), SIA facilitates automated control of minute quantities of reagent flow, flow rate, and reaction time. While water quality analyzers based on SIA have been reported, many challenges remain.

[0007] On the one hand, due to the difference in air pressure of the liquid in the liquid storage ring on each reagent pipeline, during the process of the multi-channel switching valve rotating to switch each channel, the liquid can easily enter the unintended channel due to pressure, causing liquid residue and cross contamination.

[0008] On the other hand, when using a syringe pump to extract reagents under negative pressure, the actual measurement of the reagents is easily affected by multiple factors such as the complexity of the pipeline and the relative height difference with the reagents. When using a peristaltic pump to extract metered reagents, it is difficult to precisely control and there is a pulse effect of the liquid, making it difficult to achieve accurate and stable measurement of trace liquid volumes. Summary of the Invention

[0009] The purpose of the present invention is to provide a micro-reagent ammonia nitrogen online continuous analyzer and analysis method, which can reduce reagent cross contamination, reduce reagent consumption, and realize short-interval continuous analysis.

[0010] In order to achieve the above object, the present invention provides the following technical solutions:

[0011] In a first aspect, the present invention provides a micro-reagent ammonia nitrogen online continuous analyzer, comprising a first injection pump, a second injection pump, a multi-channel valve, a liquid storage ring and a reaction tank; the liquid outlets of the first injection pump and the second injection pump are respectively connected to one end of the liquid storage ring and the circulation port of the reaction tank through different channels of the multi-channel valve; the circulation port of the reaction tank is connected to a first peristaltic pump for pumping liquid into the reaction tank or emptying the liquid in the reaction tank; the other end of the liquid storage ring is connected to a second peristaltic pump for pumping liquid into the liquid storage ring, injecting liquid in the liquid storage ring into the reaction tank or emptying the liquid in the liquid storage ring; the liquid outlets of the first injection pump and the second injection pump are connected to a third peristaltic pump for blowing air into the pipeline connecting the first injection pump or the second injection pump and the multi-channel valve; the first injection pump and the second injection pump respectively store a first reagent and a second reagent for ammonia nitrogen analysis; different channels of the multi-channel valve are respectively connected to a standard sample and a water sample for ammonia nitrogen analysis, as well as cleaning water.

[0012] In combination with the first aspect, further, the liquid outlet of the first syringe pump is connected to the second channel of the multi-channel valve through a first three-way connector, the liquid outlet of the second syringe pump is connected to the third channel of the multi-channel valve through a second three-way connector, and the third peristaltic pump is connected to the first three-way connector and the second three-way connector respectively through a third three-way connector;

[0013] One end of the liquid storage ring is connected to the common port of the multi-channel valve, and the other end of the liquid storage ring is connected to the second peristaltic pump and the overflow tank respectively through the second three-way electromagnetic liquid valve;

[0014] The first channel of the multi-channel valve is connected to the circulation port of the reaction tank and one end of the first peristaltic pump respectively through the fourth three-way connector, and the other end of the first peristaltic pump is connected to the first waste liquid tank and the first container respectively through the first three-way electromagnetic liquid valve;

[0015] The fourth channel, the fifth channel, the sixth channel, the seventh channel and the eighth channel of the multi-channel valve are connected to the second waste liquid tank, the first container, the second container, the third container and the fourth container respectively;

[0016] The first container stores cleaning water, the second container stores a first standard sample, the third container stores a second standard sample, and the fourth container stores a water sample.

[0017] In combination with the first aspect, further, the first syringe pump and the second syringe pump are both step-by-step micro-syringe pumps;

[0018] The stepping microinjection pump comprises a syringe, a fixing assembly for fixing the syringe and a pushing assembly for pushing the piston of the syringe;

[0019] The fixing assembly includes a base plate and a support plate provided on the base plate, wherein the support plate is provided with a buckle for fixing the syringe;

[0020] The propulsion assembly includes a stepper motor arranged on the base plate and a slide connected to the piston of the syringe. The rotating shaft of the stepper motor is connected to the threaded screw, and a threaded hole matching the threaded screw is opened on the slide. When the rotating shaft of the stepper motor rotates, the threaded screw rotates in the threaded hole, driving the slide to propel the piston of the syringe.

[0021] In combination with the first aspect, further, a support rod is provided between the stepping motor and the support plate, and a buckle for fixing the syringe is also provided on the support rod.

[0022] In combination with the first aspect, further, a gasket is provided on the side where the buckle contacts the syringe.

[0023] In combination with the first aspect, further, a pulley is provided at the bottom of the slide, and when the shaft of the stepper motor rotates, the slide slides on the bottom plate through the pulley; a magnetic ring limiter is provided on the bottom plate for sensing the sliding position of the pulley.

[0024] In combination with the first aspect, further, a first pipeline water flow sensor is provided at one end of the liquid storage ring close to the multi-channel valve, and a second pipeline water flow sensor is provided at one end of the liquid storage ring close to the second peristaltic pump.

[0025] In combination with the first aspect, further, the outer wall of the reaction pool is covered with a heating wire, a temperature sensor is embedded in the reaction pool, a detection light source is provided on one side of the reaction pool, a light intensity detector is provided on the other side of the reaction pool, and a cooler is also provided on the outer wall of the reaction pool; the circulation port is provided at the bottom of the reaction pool, and an overflow port is also provided at the top of the reaction pool, and the overflow port is connected to the overflow tank through a pipeline.

[0026] In a second aspect, the present invention provides a method for online continuous analysis of ammonia nitrogen using the micro-reagent online continuous ammonia nitrogen analyzer as described in the first aspect, comprising:

[0027] Step 1: Measure the initial absorbance of the empty reaction cell; pump the water sample into the liquid storage ring through the multi-channel valve and the second peristaltic pump, then inject the water sample in the liquid storage ring into the reaction cell through the multi-channel valve and the second peristaltic pump, and measure the initial blank absorbance of the water sample in the reaction cell; pump the water sample in the reaction cell into the liquid storage ring through the multi-channel valve and the second peristaltic pump, and then empty the water sample in the liquid storage ring through the multi-channel valve and the second peristaltic pump;

[0028] Step 2: inject a fixed amount of the first reagent and air into the liquid storage ring through the first syringe pump, the third peristaltic pump and the multi-channel valve, draw a fixed amount of the water sample into the liquid storage ring through the multi-channel valve and the second peristaltic pump, and inject a fixed amount of the second reagent and air into the liquid storage ring through the second syringe pump, the third peristaltic pump and the multi-channel valve, so that the second reagent, the water sample and the first reagent are stored in the liquid storage ring in sequence with air as the interval;

[0029] Step 3: The second reagent, the water sample, and the first reagent in the liquid storage ring are sequentially injected into the reaction cell through the multi-channel valve and the second peristaltic pump to perform a color reaction; during the color reaction, the water sample is pumped into the liquid storage ring through the multi-channel valve and the second peristaltic pump, and then the water sample in the liquid storage ring is emptied through the multi-channel valve and the second peristaltic pump, and step 2 is repeated; after the color reaction is completed, step 4 is performed;

[0030] Step 4: Measure the absorbance of the color-developing solution in the reaction pool, calculate the absorbance of the water sample based on the initial absorbance of the empty reaction pool, the initial blank absorbance of the water sample, and the absorbance of the color-developing solution, and calculate the concentration of ammonia nitrogen in the water sample based on the absorbance of the water sample; drain the color-developing solution in the reaction pool through the first peristaltic pump, pump the cleaning water into the reaction pool through the first peristaltic pump, and drain the cleaning water in the reaction pool through the first peristaltic pump; return to step 3 until the continuous analysis termination condition is met, and then enter step 5;

[0031] Step 5: Pump the cleaning water into the liquid storage ring through the multi-channel valve and the second peristaltic pump, inject the cleaning water in the liquid storage ring into the reaction tank through the multi-channel valve and the second peristaltic pump, pump the cleaning water in the reaction tank into the liquid storage ring through the multi-channel valve and the second peristaltic pump, and drain the cleaning water in the liquid storage ring through the multi-channel valve and the second peristaltic pump.

[0032] Combined with the second aspect, further, the calculation formula of the absorbance of the water sample is:

[0033] ;

[0034] in, represents the absorbance of the water sample, represents the absorbance of the color developing solution, represents the initial blank absorbance of the water sample, represents the correction factor, ,in, represents the initial absorbance of the empty reaction cell 5, Indicates the factory-calibrated absorbance of the empty reaction cell 5;

[0035] Calculating the concentration of ammonia nitrogen in water samples based on the absorbance of water samples includes:

[0036] Substitute the absorbance of the water sample into the ammonia nitrogen standard curve and calculate the concentration of ammonia nitrogen in the water sample according to the ammonia nitrogen standard curve;

[0037] Among them, the ammonia nitrogen standard curve is obtained by analyzing ammonia nitrogen on several groups of standard samples with known ammonia nitrogen concentrations. The ammonia nitrogen standard curve is:

[0038] ;

[0039] in, represents absorbance, Indicates the concentration of ammonia nitrogen, represents the slope of the ammonia nitrogen standard curve, It represents the intercept of the ammonia nitrogen standard curve;

[0040] Substitute the absorbance of the water sample into the ammonia nitrogen standard curve and calculate the concentration of ammonia nitrogen in the water sample:

[0041] ;

[0042] in, Indicates the concentration of ammonia nitrogen in the water sample.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) Compared with the existing ammonia nitrogen online analyzer, which must complete all steps such as pipeline rinsing, reagent metering, sampling, reaction, measurement, pipeline cleaning and emptying before starting the next set of sample measurements, the micro-reagent ammonia nitrogen online continuous analyzer provided by the present invention can support the metering and operation of the next set of water samples while the previous set of water samples reacts with the reagents, further shortening the measurement interval of the water samples and realizing high-frequency ammonia nitrogen online continuous analysis through the cooperation of the multi-channel valve, the liquid storage ring and the peristaltic pumps.

[0045] (2) When a general syringe pump extracts reagents under negative pressure, the actual measurement of the reagents is easily affected by multiple factors such as the length of the pipeline and the height difference of the sampling. The present invention adopts a stepping micro-injection pump to ensure the accuracy of the measurement of trace reagents, and uses air as a driving force to control the trace reagents to enter the liquid storage ring along the designated pipeline, thereby realizing the measurement and distribution of trace reagents in ammonia nitrogen analysis with high repeatability. The two reagents are pumped out in a unidirectional manner by the stepping micro-injection pump, and a water sample is inserted in the middle of the reagent measurement. The water sample is used to clean the residual reagents in the pipeline, reducing the cross interference of the reagents and saving the consumption of cleaning water.

[0046] (3) In the stepper microinjection pump provided by the present invention, the syringe is fixed by a buckle, which allows for convenient replacement of the syringe to replenish the analyzer reagent. In addition, in the event of corrosion of the container by the reagent, the pump motor is not affected, and the maintenance cost is low. By matching buckles of different sizes, syringes of different volumes can be adapted to meet the requirements of different reagent volume measurement ranges.

[0047] (4) In the online continuous analysis method for ammonia nitrogen provided by the present invention, the high-concentration colorimetric solution is directly discharged from the reaction tank, relatively isolated from other pipelines, reducing the subsequent cleaning pressure of the entire pipeline. For the reaction tank and key parts of the pipeline, sufficient cleaning is arranged between the previous and next samples, effectively reducing concentration memory effects and cross contamination. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 Schematic diagram of the structure of the micro-reagent ammonia nitrogen online continuous analyzer provided in an embodiment of the present invention;

[0049] Figure 2 Schematic diagram of the structure of a stepping microinjection pump provided by an embodiment of the present invention;

[0050] Figure 3 is a schematic structural diagram of a buckle provided in an embodiment of the present invention;

[0051] Figure 4 Schematic diagram of the structure of the liquid storage ring provided by an embodiment of the present invention;

[0052] Figure 5 Schematic diagram of the structure of the reaction pool provided by an embodiment of the present invention;

[0053] In the figure: 1. First injection pump; 101. Injector; 102. Bottom plate; 103. Support plate; 104. Buckle; 105. Stepper motor; 106. Slide; 107. Screw rod; 108. Support rod; 109. Washer; 110. Pulley; 111. Magnetic ring stopper; 2. Second injection pump; 3. Multi-channel valve; 300. Common port; 301. First channel; 302. Second channel; 303. Third channel; 304. Fourth channel; 305. Fifth channel; 306. Sixth channel; 307. Seventh channel; 308. Eighth channel; 309. Ninth channel; 310. Tenth channel; 4. Liquid storage ring; 401. First pipeline water flow sensor; 402. Second pipeline 1. Water flow sensor; 2. Reaction tank; 3. Heating wire; 4. Temperature sensor; 5. Detection light source; 5. Light intensity detector; 5. Cooler; 5. Circulation port; 5. Overflow port; 6. First peristaltic pump; 6. Second peristaltic pump; 6. Third peristaltic pump; 7. First three-way connector; 7. Second three-way connector; 7. Third three-way connector; 7. Fourth three-way connector; 8. First three-way electromagnetic liquid valve; 8. Second three-way electromagnetic liquid valve; 9. First waste liquid tank; 9. Second waste liquid tank; 9. First container; 9. Second container; 9. Third container; 9. Fourth container; 9. Overflow tank. DETAILED DESCRIPTION

[0054] The technical solution of the present invention will be further described in detail below in conjunction with specific implementation methods.

[0055] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention and are not to be construed as limiting the present invention. The embodiments of the present invention and the technical features in the embodiments may be combined with each other unless there is a conflict.

[0056] Example 1:

[0057] This embodiment provides a micro-reagent ammonia nitrogen online continuous analyzer, such as Figure 1 As shown, the system includes a first syringe pump 1, a second syringe pump 2, a multichannel valve 3, a liquid storage ring 4, and a reaction cell 5. The liquid outlets of the first syringe pump 1 and the second syringe pump 2 are connected to one end of the liquid storage ring 4 and the circulation port 506 of the reaction cell 5 through different channels of the multichannel valve 3. The circulation port 506 of the reaction cell 5 is connected to a first peristaltic pump 601 for pumping liquid into the reaction cell 5 or draining the liquid from the reaction cell 5. The other end of the liquid storage ring 4 is connected to a second peristaltic pump 602 for pumping liquid into the liquid storage ring 4, injecting liquid from the liquid storage ring 4 into the reaction cell 5, or draining the liquid from the liquid storage ring 4. The liquid outlets of the first syringe pump 1 and the second syringe pump 2 are connected to a third peristaltic pump 603 for injecting air into the pipeline connecting the first syringe pump 1 or the second syringe pump 2 and the multichannel valve 3. The first syringe pump 1 and the second syringe pump 2 respectively store a first reagent and a second reagent for ammonia nitrogen analysis. Different channels of the multi-channel valve 3 are respectively connected to standard samples and water samples for ammonia nitrogen analysis, as well as cleaning water.

[0058] In this embodiment, the first injection pump 1 , the second injection pump 2 , the multi-channel valve 3 and each peristaltic pump are all connected to the control terminal signal, feed back signals to the control terminal and are controlled by the control terminal.

[0059] The micro-reagent ammonia nitrogen online continuous analyzer provided in this embodiment, through the cooperation of the multi-channel valve 3, the liquid storage ring 4 and the peristaltic pumps, can support the metering and operation of the latter group of water samples and reagents while the previous group of water samples and reagents react, shorten the measurement interval of the water samples, and realize high-frequency ammonia nitrogen online continuous analysis; it can also reduce reagent cross contamination and reduce reagent consumption.

[0060] Example 2:

[0061] This embodiment provides a micro-reagent ammonia nitrogen online continuous analyzer, based on Example 1, as Figure 1As shown, the liquid outlet of the first injection pump 1 is connected to the second channel 302 of the multi-channel valve 3 through the first three-way joint 701, the liquid outlet of the second injection pump 2 is connected to the third channel 303 of the multi-channel valve 3 through the second three-way joint 702, and the third peristaltic pump 603 is connected to the first three-way joint 701 and the second three-way joint 702 respectively through the third three-way joint 703.

[0062] One end of the liquid storage ring 4 is connected to the common port 300 of the multi-channel valve 3 , and the other end of the liquid storage ring 4 is connected to the second peristaltic pump 602 and the overflow tank 907 respectively through the second three-way electromagnetic liquid valve 802 .

[0063] The first channel 301 of the multi-channel valve 3 is connected to the circulation port 506 of the reaction tank 5 and one end of the first peristaltic pump 601 through the fourth three-way connector 704, and the other end of the first peristaltic pump 601 is connected to the first waste liquid tank 901 and the first container 903 through the first three-way electromagnetic liquid valve 801.

[0064] The fourth channel 304 , the fifth channel 305 , the sixth channel 306 , the seventh channel 307 and the eighth channel 308 of the multi-channel valve 3 are connected to the second waste liquid pool 902 , the first container 903 , the second container 904 , the third container 905 and the fourth container 906 respectively.

[0065] In this embodiment, the first container 903 stores cleaning water, the second container 904 stores the first standard sample, the third container 905 stores the second standard sample, and the fourth container 906 stores the water sample.

[0066] Specifically, such as Figure 1 As shown, the multi-channel valve 3 is a ten-channel valve, and the multi-channel valve 3 also has two spare channels, namely a ninth channel 309 and a tenth channel 310 .

[0067] When the control terminal controls the multi-channel valve 3 to switch to a certain channel, it indicates that the channel is connected to the common port 300, while the other channels are blocked from the common port 300. For example, when the control terminal controls the multi-channel valve 3 to switch to the first channel 301, it indicates that the first channel 301 is connected to the common port 300, while the other channels are blocked from the common port 300.

[0068] In this embodiment, each three-way joint can be a T-type three-way joint, a Y-type three-way joint or any other type of three-way joint.

[0069] Specifically, such as Figure 1As shown, the liquid outlet of the first injection pump 1 is connected to the first end of the first three-way joint 701 through a pipeline, the second end of the first three-way joint 701 is connected to the second channel 302 of the multi-channel valve 3 through a pipeline, the liquid outlet of the second injection pump 2 is connected to the first end of the second three-way joint 702 through a pipeline, the second end of the second three-way joint 702 is connected to the third channel 303 of the multi-channel valve 3 through a pipeline, one end of the third peristaltic pump 603 is connected to the third end of the third three-way joint 703 through a pipeline, the other end of the third peristaltic pump 603 is connected to the outside air, the first end of the third three-way joint 703 is connected to the third end of the first three-way joint 701 through a pipeline, and the second end of the third three-way joint 703 is connected to the third end of the second three-way joint 702 through a pipeline.

[0070] One end of the liquid storage ring 4 is connected to the common port 300 of the multi-channel valve 3 through a pipeline, and the other end of the liquid storage ring 4 is connected to the third end of the second three-way electromagnetic liquid valve 802 through a pipeline. The first end of the second three-way electromagnetic liquid valve 802 is connected to one end of the second peristaltic pump 602 through a pipeline, and the second end of the second three-way electromagnetic liquid valve 802 is connected to the overflow tank 907 through a pipeline. The other end of the second peristaltic pump 602 is connected to the outside air.

[0071] The first channel 301 of the multi-channel valve 3 is connected to the first end of the fourth three-way connector 704 through a pipeline, the second end of the fourth three-way connector 704 is connected to the circulation port 506 of the reaction tank 5 through a pipeline, the third end of the fourth three-way connector 704 is connected to one end of the first peristaltic pump 601 through a pipeline, the other end of the first peristaltic pump 601 is connected to the third end of the first three-way electromagnetic liquid valve 801 through a pipeline, the first end of the first three-way electromagnetic liquid valve 801 is connected to the first waste liquid tank 901 through a pipeline, and the second end of the first three-way electromagnetic liquid valve 801 is connected to the first container 903 through a pipeline.

[0072] The fourth channel 304, the fifth channel 305, the sixth channel 306, the seventh channel 307 and the eighth channel 308 of the multi-channel valve 3 are connected to the second waste liquid tank 902, the first container 903, the second container 904, the third container 905 and the fourth container 906 through pipelines respectively.

[0073] In this embodiment, the first three-way electromagnetic liquid valve 801 and the second three-way electromagnetic liquid valve 802 are both connected to the control terminal signal, feed back signals to the control terminal and are controlled by the control terminal.

[0074] The initial state (i.e., power-off state) of the first three-way electromagnetic liquid valve 801 and the second three-way electromagnetic liquid valve 802 is set as: the first port and the third port are connected, and the second port and the third port are closed; the power-on state is: the first port and the third port are closed, and the second port and the third port are connected.

[0075] Specifically, when the control terminal controls the first three-way electromagnetic liquid valve 801 to be energized, the first port and the third port of the first three-way electromagnetic liquid valve 801 are closed, and the second port and the third port of the first three-way electromagnetic liquid valve 801 are connected, that is, the pipeline between the first peristaltic pump 601 and the first waste liquid tank 901 is closed, and the pipeline between the first peristaltic pump 601 and the first container 903 is connected; otherwise, the first port and the third port of the first three-way electromagnetic liquid valve 801 are connected, and the second port and the third port of the first three-way electromagnetic liquid valve 801 are closed, that is, the pipeline between the first peristaltic pump 601 and the first waste liquid tank 901 is connected, and the pipeline between the first peristaltic pump 601 and the first container 903 is closed.

[0076] When the control terminal controls the second three-way electromagnetic liquid valve 802 to be energized, the first port and the third port of the second three-way electromagnetic liquid valve 802 are closed, and the second port and the third port of the second three-way electromagnetic liquid valve 802 are connected, that is, the pipeline between the second peristaltic pump 602 and the liquid storage ring 4 is closed, and the pipeline between the second peristaltic pump 602 and the overflow tank 907 is connected; otherwise, the first port and the third port of the second three-way electromagnetic liquid valve 802 are connected, and the second port and the third port of the second three-way electromagnetic liquid valve 802 are closed, that is, the pipeline between the second peristaltic pump 602 and the liquid storage ring 4 is connected, and the pipeline between the second peristaltic pump 602 and the overflow tank 907 is closed.

[0077] The micro-reagent ammonia nitrogen online continuous analyzer provided in this embodiment realizes the opening and closing of different pipelines through the multi-channel valve 3 in conjunction with each peristaltic pump and the three-way electromagnetic liquid valve. It can not only support the metering of the next group of water samples and reagents during the reaction process of the previous group of water samples and reagents, but also avoid cross-interference of reagents.

[0078] Example 3:

[0079] This embodiment provides a micro-reagent ammonia nitrogen online continuous analyzer, based on Example 1, as Figure 1 As shown, the first injection pump 1 and the second injection pump 2 are both stepping micro-injection pumps.

[0080] In this embodiment, Figure 2 As shown, the stepping micro-injection pump includes a syringe 101 , a fixing component for fixing the syringe 101 , and a pushing component for pushing the piston of the syringe 101 .

[0081] Specifically, such as Figure 2 As shown, the fixing assembly includes a base plate 102 and a support plate 103 provided on the base plate 102 , and a buckle 104 for fixing the syringe 101 is provided on the support plate 103 .

[0082] The propulsion assembly includes a stepper motor 105 arranged on the base plate 102, and a slide 106 connected to the piston of the syringe 101. The rotating shaft of the stepper motor 105 is connected to the threaded screw 107. A threaded hole matching the threaded screw 107 is provided on the slide 106. When the rotating shaft of the stepper motor 105 rotates, the threaded screw 107 rotates in the threaded hole, driving the slide 106 to propel the piston of the syringe 101.

[0083] In this embodiment, the stepper motor 105 is signal-connected to the control terminal, feeds back signals to the control terminal and is controlled by the control terminal.

[0084] Specifically, when the control terminal controls the stepper motor 105 to rotate, the rotating shaft of the stepper motor 105 drives the threaded screw 107 to rotate in the threaded hole of the slide 106, so that the slide 106 moves relative to the threaded screw 107, thereby advancing the piston of the syringe 101.

[0085] In this embodiment, the capacity of the syringe 101 is 5 mL, and the metering volume of a single reagent is 20 μL to 1000 μL.

[0086] Given that the cross-sectional area of ​​the empty barrel of the syringe 101 is fixed, the positioning accuracy of the stepper motor 105's rotating shaft driving the threaded screw 107 to rotate in the threaded hole of the slide 106 is 0.02 mm. When the diameter of the empty barrel of the syringe 101 is 13 mm, the volume of liquid pushed out by the syringe 101 each time can be accurately adjusted to approximately 1.3 μL.

[0087] The micro-reagent ammonia nitrogen online continuous analyzer provided by the present embodiment adopts a step-by-step micro-injection pump, which can ensure the accuracy of micro-reagent metering, and utilizes air as a driving force to control micro-reagent to enter the liquid storage ring 4 along the specified pipeline, so that the metering and distribution of micro-reagents in ammonia nitrogen analysis can be realized, and the repeatability is high. The first reagent and the second reagent are respectively pumped out by the first syringe pump 1 and the second syringe pump 2 unidirectionally, and the water sample metering can be inserted in the middle of the reagent metering. The residual of the reagent in the water sample cleaning pipeline can be used to reduce the reagent cross interference, and the consumption of cleaning water can be saved. In the step-by-step micro-injection pump, syringe 101 is fixed by buckle 104, which can easily replace syringe 101, realize the supplement of analyzer reagent, and in case the corrosion of the reagent to the container itself occurs, the motor of the pump is not affected, and the maintenance cost is small. By arranging buckles 104 of different sizes, syringes 101 of different volumes can be adapted to meet the reagent volume measurement requirements of different scopes.

[0088] Example 4:

[0089] This embodiment provides a micro-reagent ammonia nitrogen online continuous analyzer, based on Example 3, as Figure 2As shown, a support rod 108 is provided between the stepping motor 105 and the support plate 103 , and a buckle 104 for fixing the syringe 101 is also provided on the support rod 108 .

[0090] In this embodiment, the buckles 104 on the support plate 103 and the buckles 104 on the support rod 108 respectively fix the two ends of the syringe 101. The buckles 104 on the support plate 103 and the buckles 104 on the support rod 108 are kept at the same height.

[0091] Specifically, such as Figure 3 As shown, one side of the buckle 104 is movably connected by a hinge, and the other side of the buckle 104 can be rotated around the hinge to open and close. The other side of the buckle 104 is provided with a pair of screw holes, and bolts are passed through the pair of screw holes to close the buckle 104 and fix the syringe 101.

[0092] The micro-reagent ammonia nitrogen online continuous analyzer provided in this embodiment secures the syringe 101 with two clips 104, thereby improving the stability of the syringe 101. One end of the clip 104 is hinged for opening and closing, while the other end of the clip 104 is secured to the syringe 101 by a bolt passing through a pair of screw holes. This simple structure facilitates replacement of the syringe 101 or replenishment of reagents.

[0093] Example 5:

[0094] This embodiment provides a micro-reagent ammonia nitrogen online continuous analyzer, based on embodiment 3 or embodiment 4, as Figure 3 As shown, a gasket 109 is provided on the side of the buckle 104 that fits with the syringe 101 .

[0095] Specifically, the gasket 109 is made of rubber.

[0096] In the micro-reagent ammonia nitrogen online continuous analyzer provided in this embodiment, a gasket 109 is provided on the side where the buckle 104 contacts the syringe 101. This reduces wear on the outer wall of the syringe 101 caused by the buckle 104 and prevents damage to the syringe 101 during the process of securing the syringe 101 with the buckle 104. The rubber material not only increases the stability of the contact surface, but also accommodates minor dimensional differences caused by different syringe 101 manufacturing processes within a certain range.

[0097] Example 6:

[0098] This embodiment provides a micro-reagent ammonia nitrogen online continuous analyzer, based on Example 3, as Figure 2 As shown, a pulley 110 is provided at the bottom of the slide 106. When the shaft of the stepper motor 105 rotates, the slide 106 slides on the bottom plate 102 through the pulley 110. A magnetic ring limiter 111 is provided on the bottom plate 102 for sensing the sliding position of the pulley 110.

[0099] In this embodiment, the magnetic ring limiter 111 is connected to the control terminal signal, feeds back signals to the control terminal and is controlled by the control terminal.

[0100] Specifically, two magnetic ring stoppers 111 are provided on the base plate 102, one at each end of the base plate 102, for sensing the sliding distance of the pulley 110 on the base plate 102. When the pulley 110 slides past the magnetic ring stoppers 111, the magnetic ring stoppers 111 generate a sensing signal and feed it back to the control terminal.

[0101] When the control terminal receives the induction signal generated by the magnetic ring limiter 111 at the end of the bottom plate 102, it indicates that the reagent in the syringe 101 is about to be injected, and the control terminal prompts that the reagent in the syringe 101 needs to be supplemented or replaced.

[0102] The micro-reagent ammonia nitrogen online continuous analyzer provided in this embodiment uses pulley 110 to reduce the resistance of slide 106 when sliding relative to base plate 102, preventing the piston of syringe 101 from getting stuck during advancement and improving the metering accuracy of the reagent. Magnetic ring stopper 111 not only assists in positioning but also indicates that the reagent in syringe 101 needs to be replenished or replaced.

[0103] Example 7:

[0104] This embodiment provides a micro-reagent ammonia nitrogen online continuous analyzer, based on Example 1, as Figure 1 As shown, a first pipeline water flow sensor 401 is provided at one end of the liquid storage ring 4 close to the multi-channel valve 3 , and a second pipeline water flow sensor 402 is provided at one end of the liquid storage ring 4 close to the second peristaltic pump 602 .

[0105] In this embodiment, the effective volume of the liquid storage ring 4 is larger than the total volume of the reagents and water samples required for one measurement. Liquids of different components are stored independently with air as the interval, and follow the first-in-last-out principle.

[0106] Specifically, such as Figure 4 As shown, the liquid storage ring 4 can be a section of spiral curved pipe, such as Figure 1 As shown, the liquid storage ring 4 can also be a plurality of sections of spirally curved pipes connected by straight pipes to form an uneven pipeline, or can be any other shape.

[0107] In this embodiment, the first pipeline water flow sensor 401 and the second pipeline water flow sensor 402 are both signal-connected to the control terminal, feed back signals to the control terminal, and are controlled by the control terminal.

[0108] Specifically, when liquid flows through the first pipeline water flow sensor 401 and the second pipeline water flow sensor 402, the first pipeline water flow sensor 401 and the second pipeline water flow sensor 402 can generate water flow signals and feed them back to the control terminal. The control terminal can judge the amount of liquid flowing through the first pipeline water flow sensor 401 based on the duration of the water flow signal fed back by the first pipeline water flow sensor 401 and the set flow value of the corresponding peristaltic pump, and then control the amount of liquid injected into the liquid storage ring 4 or the amount of liquid extracted from the liquid storage ring 4. It can also judge whether the liquid storage ring 4 overflows based on whether the second pipeline water flow sensor 402 feeds back a water flow signal.

[0109] The micro-reagent ammonia nitrogen online continuous analyzer provided in this embodiment uses the first pipeline water flow sensor 401 to measure the liquid injected into the liquid storage ring 4 or the liquid extracted from the liquid storage ring 4, and uses the second pipeline water flow sensor 402 to prevent the liquid storage ring 4 from overflowing, which can further improve the measurement accuracy of water samples and reagents and reduce the consumption of water samples and reagents.

[0110] Example 8:

[0111] This embodiment provides a micro-reagent ammonia nitrogen online continuous analyzer, based on Example 1, as Figure 4 As shown, the outer wall of the reaction pool 5 is covered with a heating wire 501, a temperature sensor 502 is embedded in the reaction pool 5, a detection light source 503 is provided on one side of the reaction pool 5, a light intensity detector 504 is provided on the other side of the reaction pool 5, and a cooler 505 is also provided on the outer wall of the reaction pool 5; a circulation port 506 is provided at the bottom of the reaction pool 5, and an overflow port 507 is also provided at the top of the reaction pool 5, and the overflow port 507 is connected to the overflow pool 907 through a pipeline.

[0112] In this embodiment, the heating wire 501, the temperature sensor 502, the detection light source 503, the light intensity detector 504 and the cooler 505 are all signal-connected to the control terminal, feed back signals to the control terminal and are controlled by the control terminal.

[0113] Specifically, the control terminal can collect the temperature of the liquid in the reaction pool 5 through the temperature sensor 502, and control the heating wire 501 to continuously heat or stop heating the liquid in the reaction pool 5 according to the temperature of the liquid in the reaction pool 5. It can also control the cooler 505 to continuously cool or stop cooling the liquid in the reaction pool 5 according to the temperature of the liquid in the reaction pool 5.

[0114] The control terminal can also control the detection light source 503 to emit light of a specified wavelength band through the reaction pool 5 to reach the receiving end of the light intensity detector 504, and measure the absorbance of the reaction pool 5 or the liquid in the reaction pool 5 through the light intensity detector 504.

[0115] The micro-reagent ammonia nitrogen online continuous analyzer provided in this embodiment has a detection light source 503 emitting light with a typical wavelength of approximately 700 nm and a narrow half-width (FWHM). The control terminal utilizes a voltage-stabilized design to ensure stable optical power, resulting in high overall measurement accuracy, good stability, and good repeatability. High-concentration color-developing wastewater in the reaction tank 5 can be directly discharged through the circulation port 506, relatively isolated from other pipelines, reducing the subsequent cleaning pressure of the entire pipeline.

[0116] Example 9:

[0117] This embodiment provides a method for online continuous analysis of ammonia nitrogen using the micro-reagent online continuous ammonia nitrogen analyzer provided in Embodiments 1 to 8 of the present invention, comprising:

[0118] Step 1: Measure the initial absorbance of the empty reaction cell 5; pump the water sample into the liquid storage ring 4 through the multi-channel valve 3 and the second peristaltic pump 602, then inject the water sample in the liquid storage ring 4 into the reaction cell 5 through the multi-channel valve 3 and the second peristaltic pump 602, and measure the initial blank absorbance of the water sample in the reaction cell 5; pump the water sample in the reaction cell 5 into the liquid storage ring 4 through the multi-channel valve 3 and the second peristaltic pump 602, and then drain the water sample in the liquid storage ring 4 through the multi-channel valve 3 and the second peristaltic pump 602;

[0119] Step 2: inject a fixed amount of the first reagent and air into the liquid storage ring 4 through the first syringe pump 1, the third peristaltic pump 603 and the multi-channel valve 3, draw a fixed amount of the water sample into the liquid storage ring 4 through the multi-channel valve 3 and the second peristaltic pump 602, and inject a fixed amount of the second reagent and air into the liquid storage ring 4 through the second syringe pump 2, the third peristaltic pump 603 and the multi-channel valve 3, so that the second reagent, the water sample, and the first reagent are stored in the liquid storage ring 4 in sequence with air as the interval;

[0120] Step 3: The second reagent, the water sample, and the first reagent in the liquid storage ring 4 are sequentially injected into the reaction cell 5 through the multi-channel valve 3 and the second peristaltic pump 602 to perform a color reaction. During the color reaction, the water sample is pumped into the liquid storage ring 4 through the multi-channel valve 3 and the second peristaltic pump 602, and then the water sample in the liquid storage ring 4 is emptied through the multi-channel valve 3 and the second peristaltic pump 602, and step 2 is repeated. After the color reaction is completed, step 4 is entered.

[0121] Step 4: Measure the absorbance of the color-developing solution in the reaction tank 5, calculate the absorbance of the water sample based on the initial absorbance of the empty reaction tank 5, the initial blank absorbance of the water sample, and the absorbance of the color-developing solution, and calculate the concentration of ammonia nitrogen in the water sample based on the absorbance of the water sample; drain the color-developing solution in the reaction tank 5 through the first peristaltic pump 601, pump the cleaning water into the reaction tank 5 through the first peristaltic pump 601, and drain the cleaning water in the reaction tank 5 through the first peristaltic pump 601; return to step 3 until the continuous analysis termination condition is met, and then enter step 5;

[0122] Step 5: Pump the cleaning water into the liquid storage ring 4 through the multi-channel valve 3 and the second peristaltic pump 602, inject the cleaning water in the liquid storage ring 4 into the reaction tank 5 through the multi-channel valve 3 and the second peristaltic pump 602, pump the cleaning water in the reaction tank 5 into the liquid storage ring 4 through the multi-channel valve 3 and the second peristaltic pump 602, and drain the cleaning water in the liquid storage ring 4 through the multi-channel valve 3 and the second peristaltic pump 602.

[0123] In this embodiment, the calculation formula of the absorbance of the water sample is:

[0124] ;

[0125] in, represents the absorbance of the water sample, represents the absorbance of the color developing solution, represents the initial blank absorbance of the water sample, represents the correction factor, ,in, represents the initial absorbance of the empty reaction cell 5, Indicates the factory-calibrated absorbance of the empty reaction cell 5.

[0126] Calculating the concentration of ammonia nitrogen in a water sample based on the absorbance of the water sample includes: substituting the absorbance of the water sample into an ammonia nitrogen standard curve, and calculating the concentration of ammonia nitrogen in the water sample based on the ammonia nitrogen standard curve; wherein, the ammonia nitrogen standard curve is obtained by performing ammonia nitrogen analysis on a standard sample with a known ammonia nitrogen concentration, and the ammonia nitrogen standard curve is:

[0127] ;

[0128] in, represents absorbance, Indicates the concentration of ammonia nitrogen, represents the slope of the ammonia nitrogen standard curve, Represents the intercept of the ammonia nitrogen standard curve.

[0129] Substitute the absorbance of the water sample into the ammonia nitrogen standard curve and calculate the concentration of ammonia nitrogen in the water sample:

[0130] ;

[0131] in, Indicates the concentration of ammonia nitrogen in the water sample.

[0132] Referring to the online continuous analysis method for ammonia nitrogen provided in this embodiment, ammonia nitrogen analysis was performed on several groups of standard samples with known ammonia nitrogen concentrations to obtain an ammonia nitrogen standard curve.

[0133] Specifically, referring to the online continuous analysis method of ammonia nitrogen provided in this embodiment, ammonia nitrogen analysis is performed on 4 to 6 groups of standard samples with different ammonia nitrogen concentrations, the absorbance of each group of standard samples is obtained, and the ammonia nitrogen concentration and absorbance of each group of standard samples are data fitted to obtain an ammonia nitrogen standard curve.

[0134] After obtaining the ammonia nitrogen standard curve, the ammonia nitrogen standard curve is input into the control terminal. When the control terminal calculates the concentration of ammonia nitrogen in the water sample, the ammonia nitrogen standard curve can be called in real time.

[0135] Referring to the online continuous analysis method for ammonia nitrogen provided in this embodiment, ammonia nitrogen analysis is performed on the first standard sample and the second standard sample with known ammonia nitrogen concentration (actual concentration) in the second container 904 and the third container 905, respectively. The absorbance of the first standard sample and the second standard sample is obtained, and the ammonia nitrogen concentration (measured concentration) of the first standard sample and the second standard sample is calculated in combination with the ammonia nitrogen standard curve. The ammonia nitrogen standard curve is corrected based on the ratio of the measured concentration to the actual concentration of the first standard sample and the second standard sample.

[0136] The specific steps of measuring the ammonia nitrogen concentration of the first standard sample and the second standard sample are the same as the steps of measuring the ammonia nitrogen concentration of the water sample in this embodiment.

[0137] The online continuous analysis method for ammonia nitrogen provided in this embodiment can solve the problems of large reagent consumption, large amount of waste liquid generated, and low continuous analysis efficiency in existing online ammonia nitrogen analysis. Through the cooperation of the multi-channel valve, the liquid storage ring and each peristaltic pump, it can support the metering and operation of the latter group of water samples while the previous group of water samples reacts with the reagent, further shortening the measurement interval of the water samples, realizing high-frequency online continuous analysis of ammonia nitrogen, and providing effective technical support for the high-frequency real-time monitoring needs of water quality emergency monitoring and long-term management.

[0138] Example 10:

[0139] This embodiment provides a method for online continuous analysis of ammonia nitrogen using the micro-reagent online continuous ammonia nitrogen analyzer provided in Examples 1 to 8 of the present invention.

[0140] In this embodiment, the components of each reagent and its corresponding standard solution are:

[0141] First reagent: 70g / L sodium hydroxide, 98g / L sodium hypochlorite (10% available chlorine);

[0142] Second reagent: 60g / L sodium hydroxide, 70g / L salicylic acid, 80g / L L-tartaric acid, 10g / L sodium nitrosoferricyanide;

[0143] Standard solution corresponding to the first and second reagents: NH4 + The concentration of ammonium chloride is 1000 mg / L.

[0144] Taking the first reagent as an example, the typical process of reagent volume dosage is explained:

[0145] The control terminal controls the multi-channel valve 3 to switch to the second channel 302, controls the second three-way electromagnetic liquid valve 802 to be energized, controls the stepper motor 105 of the first injection pump 1 to work, injects a quantitative amount of the first reagent into the pipeline through the first three-way connector 701, controls the third peristaltic pump 603 to rotate clockwise, and blows air into the pipeline through the third three-way connector 703. The air separates the liquid column of the first reagent in the first three-way connector 701, and injects the first reagent into the liquid storage ring 4 along the pipeline. When the first pipeline water flow sensor 401 generates a water flow signal from presence to absence, the third peristaltic pump 603 is controlled to stop rotating, and the second three-way electromagnetic liquid valve 802 is controlled to be de-energized, so that the liquid column of the first reagent in the liquid storage ring 4 remains stable.

[0146] To verify the actual reagent volume of the micro-reagent online continuous ammonia nitrogen analyzer provided in this embodiment, a centrifuge tube was used to replace the reaction cell 5 and connect to the first channel 301 of the multichannel valve 3 to load the reagent. The control terminal, controlled by a program, metered volumes of 20 μL, 50 μL, 100 μL, and 500 μL of the first reagent, respectively. After the first reagent metering step was completed, the control terminal controlled the multichannel valve 3 to switch to the first channel 301 and controlled the second peristaltic pump 602 to rotate clockwise, injecting the first reagent from the liquid storage ring 4 into the centrifuge tube. The reagent in the centrifuge tube was weighed using an electronic balance, and the actual metered volume of the first reagent was calculated using the formula: volume (V) = mass (m) / volume density (ρ). Each volume was measured three times.

[0147] The actual measurement volume and error data of the first reagent are shown in Table 1.

[0148] Table 1: Actual measurement volume and error data of the first reagent

[0149] .

[0150] As shown in Table 1, in the volume range of 20 μL to 500 μL, the relative error between the mean of the actual measured volume and the set value is less than 4%, and the maximum deviation between the single value of the actual measured volume and the set value is less than 5%.

[0151] The method for online continuous analysis of ammonia nitrogen provided in this embodiment specifically comprises the following steps:

[0152] Step 1: Initial pipeline rinsing;

[0153] Step 1.1: The control terminal controls the detection light source 503 to emit light of a specified wavelength band through the empty reaction cell 5 to the receiving end of the light intensity detector 504, and the light intensity detector 504 measures the initial absorbance of the empty reaction cell 5;

[0154] Step 1.2: The control terminal controls the multi-channel valve 3 to switch to the eighth channel 308, controls the second three-way electromagnetic liquid valve 802 to be energized, controls the second peristaltic pump 602 to rotate counterclockwise, and pumps an appropriate amount of water sample from the fourth container 906 along the pipeline into the liquid storage ring 4. When the first pipeline water flow sensor 401 generates a water flow signal for 4 seconds, controls the second peristaltic pump 602 to stop rotating, controls the multi-channel valve 3 to switch to the first channel 301, controls the second peristaltic pump 602 to rotate clockwise, injects the water sample in the liquid storage ring 4 along the pipeline into the reaction tank 5, and controls the second peristaltic pump 602 to stop rotating;

[0155] Step 1.3: The control terminal controls the detection light source 503 to emit light of a specified wavelength band through the reaction cell 5 containing the water sample to reach the receiving end of the light intensity detector 504, and the light intensity detector 504 measures the initial blank absorbance of the water sample in the reaction cell 5;

[0156] Step 1.4: The control terminal controls the second peristaltic pump 602 to rotate counterclockwise, draws all the water samples in the reaction tank 5 into the liquid storage ring 4 along the pipeline, controls the second peristaltic pump 602 to stop rotating, controls the multi-channel valve 3 to switch to the fourth channel 304, controls the second peristaltic pump 602 to rotate clockwise, drains the water samples in the liquid storage ring 4 into the second waste liquid tank 902 along the pipeline, and controls the second peristaltic pump 602 to stop rotating.

[0157] Step 2: Measuring reagents and water samples;

[0158] Step 2.1: The control terminal controls the multi-channel valve 3 to switch to the second channel 302, controls the second three-way electromagnetic liquid valve 802 to be energized, controls the stepper motor 105 of the first syringe pump 1 to operate, injects a fixed amount of the first reagent into the pipeline through the first three-way connector 701, controls the third peristaltic pump 603 to rotate clockwise, and blows air into the pipeline through the third three-way connector 703. The air separates the liquid column of the first reagent in the first three-way connector 701, and injects the first reagent into the liquid storage ring 4 along the pipeline. When the water flow sensor 401 of the first pipeline generates a water flow signal from being present to being absent, controls the third peristaltic pump 603 to stop rotating, controls the second three-way electromagnetic liquid valve 802 to be de-energized, and ensures that the liquid column of the first reagent in the liquid storage ring 4 remains stable.

[0159] Step 2.2: The control terminal controls the multi-channel valve 3 to switch to the eighth channel 308, controls the second peristaltic pump 602 to rotate counterclockwise, pumps a fixed amount of water sample from the fourth container 906 along the pipeline into the liquid storage ring 4, and controls the second peristaltic pump 602 to stop rotating;

[0160] Specifically, in step 2.2, the water sample is used to clean the residue of the first reagent in the common pipeline of the multi-channel valve 3, which can further reduce the cross interference of the reagents and save the consumption of cleaning water.

[0161] Step 2.3: The control terminal controls the multi-channel valve 3 to switch to the third channel 303, controls the second three-way electromagnetic liquid valve 802 to be energized, controls the stepper motor 105 of the second syringe pump 2 to work, injects a fixed amount of the second reagent into the pipeline through the second three-way connector 702, controls the third peristaltic pump 603 to rotate clockwise, and blows air into the pipeline through the third three-way connector 703. The air separates the liquid column of the second reagent in the second three-way connector 702, and injects the second reagent into the liquid storage ring 4 along the pipeline. When the first pipeline water flow sensor 401 generates a water flow signal from presence to absence, the third peristaltic pump 603 is controlled to stop rotating, and the second three-way electromagnetic liquid valve 802 is controlled to be de-energized, so that the second reagent, air, water sample, air, and first reagent are stored in the liquid storage ring 4 in sequence, and the position of the liquid column in the liquid storage ring 4 is kept stable.

[0162] Step 3: color reaction;

[0163] Step 3.1: The control terminal controls the multi-channel valve 3 to switch to the first channel 301, controls the second peristaltic pump 602 to rotate clockwise, and injects the second reagent, water sample, and first reagent in the liquid storage ring 4 into the reaction cell 5 along the pipeline in sequence. Air is continuously blown into the reaction cell 5, and the second peristaltic pump 602 is controlled to stop rotating.

[0164] Specifically, after the second reagent, water sample and first reagent in the liquid storage ring 4 are sequentially injected into the reaction pool 5 along the pipeline, air is continuously blown into the reaction pool 5 , and the generated bubbles can further mix the liquid in the reaction pool 5 .

[0165] Step 3.2: The control terminal controls the heating wire 501 to start heating, controls the temperature sensor 502 to collect the temperature of the liquid in the reaction tank 5 in real time, and when the temperature of the liquid in the reaction tank 5 reaches the reaction temperature, controls the heating wire 501 to stop heating and start the timed reaction. After the timed reaction is completed, controls the cooler 505 to start cooling. When the temperature of the liquid in the reaction tank 5 reaches the cooling temperature, controls the cooler 505 to stop cooling.

[0166] Specifically, the reaction temperature of the color development reaction is 40°C, and the timed reaction time is 5 minutes. The total duration of step 3.2 is equal to the sum of the heating and timed reaction time. When the ambient temperature is lower than the reaction temperature, the heating time is equal to the time it takes for the heating wire 501 to heat the temperature of the liquid in the reaction tank 5 to the reaction temperature, and the maximum time is no more than 3 minutes. When the ambient temperature is higher than the reaction temperature, there is no heating time.

[0167] Step 3.3: The control terminal controls the multi-channel valve 3 to switch to the eighth channel 308, controls the second peristaltic pump 602 to rotate counterclockwise, draws an appropriate amount of water sample from the fourth container 906 along the pipeline into the liquid storage ring 4, controls the second peristaltic pump 602 to stop rotating, controls the multi-channel valve 3 to switch to the fourth channel 304, controls the second peristaltic pump 602 to rotate clockwise, drains the water sample in the liquid storage ring 4 along the pipeline to the second waste liquid tank 902, and controls the second peristaltic pump 602 to stop rotating.

[0168] Specifically, if only a single analysis of ammonia nitrogen is performed, or it is the last round of measurement of online continuous analysis of ammonia nitrogen, then after executing step 3.2, skip step 3.3 and go directly to step 4. If online continuous analysis of ammonia nitrogen is required and it is not the last round of measurement of online continuous analysis of ammonia nitrogen, then while executing step 3.2, execute step 3.3 synchronously and then go to step 4. This can shorten the interval between water sample measurements and improve the efficiency of online continuous analysis of ammonia nitrogen.

[0169] Step 4: Ammonia nitrogen analysis;

[0170] Step 4.1: The control terminal controls the detection light source 503 to emit light of a specified wavelength band through the reaction cell 5 containing the color developing solution to reach the receiving end of the light intensity detector 504, and the light intensity detector 504 measures the absorbance of the color developing solution in the reaction cell 5;

[0171] Step 4.2: The control terminal calculates the absorbance of the water sample according to the initial absorbance of the empty reaction cell 5, the initial blank absorbance of the water sample, and the absorbance of the color developing solution, and calculates the concentration of ammonia nitrogen in the water sample according to the absorbance of the water sample;

[0172] Step 4.3: The control terminal controls the first peristaltic pump 601 to rotate counterclockwise to drain the color-developing liquid in the reaction tank 5 along the pipeline to the first waste liquid tank 901; the control terminal controls the first peristaltic pump 601 to stop rotating, controls the first three-way electromagnetic liquid valve 801 to be energized, controls the first peristaltic pump 601 to rotate clockwise, and draws an appropriate amount of cleaning water from the first container 903 along the pipeline to the reaction tank 5; the control terminal controls the first peristaltic pump 601 to stop rotating, controls the first three-way electromagnetic liquid valve 801 to be de-energized, controls the first peristaltic pump 601 to rotate counterclockwise, drains the cleaning water in the reaction tank 5 along the pipeline to the first waste liquid tank 901, and controls the first peristaltic pump 601 to stop rotating.

[0173] Specifically, if only a single analysis of ammonia nitrogen is performed, or the last round of measurement of online continuous analysis of ammonia nitrogen has been completed, then after executing step 4.3, directly proceed to step 5. If online continuous analysis of ammonia nitrogen is required, and it is not the last round of measurement of online continuous analysis of ammonia nitrogen, then after executing step 4.3, return to step 3 and perform the next water sample measurement until the continuous analysis termination condition is met, and then proceed to step 5.

[0174] Step 5: Final pipeline cleaning.

[0175] Step 5.1: The control terminal controls the multi-channel valve 3 to switch to the fifth channel 305, controls the second peristaltic pump 602 to rotate counterclockwise, and pumps an appropriate amount of cleaning water from the first container 903 along the pipeline to the liquid storage ring 4. When the first pipeline water flow sensor 401 generates a water flow signal for 4 seconds, the second peristaltic pump 602 is controlled to stop rotating, and the multi-channel valve 3 is controlled to switch to the first channel 301. The second peristaltic pump 602 is controlled to rotate clockwise to inject the cleaning water in the liquid storage ring 4 into the reaction tank 5 along the pipeline. The second peristaltic pump 602 is controlled to rotate counterclockwise. The cleaning water in the reaction tank 5 is pumped into the liquid storage ring 4 along the pipeline, the second peristaltic pump 602 is controlled to stop rotating, the multi-channel valve 3 is controlled to switch to the fourth channel 304, the second peristaltic pump 602 is controlled to rotate clockwise, and the cleaning water in the liquid storage ring 4 is emptied into the second waste liquid tank 902 along the pipeline, the second peristaltic pump 602 is controlled to stop rotating, the multi-channel valve 3 is controlled to switch to the eighth channel 308, the second peristaltic pump 602 is controlled to rotate clockwise, and the water sample in the pipeline is emptied into the fourth container 906, and the second peristaltic pump 602 is controlled to stop rotating.

[0176] In this embodiment, the second waste liquid pool 902 collects low-concentration contaminated waste liquid from pipeline rinsing and cleaning, which can be discharged after simple treatment, while the high-concentration color development waste liquid that requires special treatment is collected separately in the first waste liquid pool 901 for subsequent processing.

[0177] Testing for a single analysis of ammonia nitrogen:

[0178] The standard solutions corresponding to the first reagent and the second reagent were diluted to standard solutions with concentrations of 0 mg / L, 0.5 mg / L, 1 mg / L, 2 mg / L, and 10 mg / L, and the injection volume of the standard solution was kept consistent with the injection volume of the water sample. According to the ammonia nitrogen online continuous analysis method provided in Example 10, the micro-reagent ammonia nitrogen online continuous analyzer provided in Examples 1 to 8 was operated to carry out a single ammonia nitrogen analysis test. The total running time of a single process was less than 15 min, and the absorbance corresponding to the standard solutions of different concentrations was recorded respectively. According to the ammonia nitrogen standard curve, the test results of the standard solutions of different concentrations were obtained. The test results of the standard solutions of different concentrations are shown in Table 2.

[0179] Table 2: Test results of standard solutions with different concentrations

[0180] .

[0181] Test the online continuous analysis of ammonia nitrogen:

[0182] The standard solutions corresponding to the first reagent and the second reagent were diluted to a standard solution with a concentration of 2 mg / L, and the injection volume of the standard solution was kept consistent with the injection volume of the water sample. According to the ammonia nitrogen online continuous analysis method provided in Example 10, the micro-reagent ammonia nitrogen online continuous analyzer provided in Examples 1 to 8 was operated to carry out an ammonia nitrogen online continuous analysis test. The ammonia nitrogen concentration in the water sample was calculated based on the absorbance obtained by continuous measurement and the ammonia nitrogen standard curve. The interval between adjacent ammonia nitrogen concentration measurements was less than 8 minutes. The results of the ammonia nitrogen online continuous analysis test are shown in Table 3.

[0183] Table 3: Ammonia nitrogen online continuous analysis test results

[0184] .

[0185] As shown in Examples 1 to 8 of the present invention, the present invention has realized the metering and distribution of trace reagents in the online automatic analysis of ammonia nitrogen, and has the advantages of small volume, high repeatability, and few cross interference. As shown in Example 10, the relative error of the test result of the standard solution of different concentrations can meet the error requirement specified in current standards, illustrating that the micro-reagent ammonia nitrogen online continuous analyzer provided by the present invention and analytical method thereof can accurately and reliably monitor the content of ammonia nitrogen in water quality. While the previous group of water sample reacted, the latter group of water sample was measured in parallel, shortening the detection interval of water sample, and the adjacent ammonia nitrogen concentration detection value produced an interval less than 8min, realizing the continuous analysis of ammonia nitrogen concentration short interval.

[0186] The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A micro-reagent ammonia nitrogen online continuous analyzer, characterized in that: The invention comprises a first injection pump (1), a second injection pump (2), a multi-channel valve (3), a liquid storage ring (4) and a reaction pool (5); the liquid outlets of the first injection pump (1) and the second injection pump (2) are connected to one end of the liquid storage ring (4) and the circulation port (506) of the reaction pool (5) through different channels of the multi-channel valve (3); the circulation port (506) of the reaction pool (5) is connected to a first peristaltic pump (601) for pumping liquid into the reaction pool (5) or emptying the liquid in the reaction pool (5); the other end of the liquid storage ring (4) is connected to a first peristaltic pump (601) for pumping liquid into the liquid storage ring (4), a second peristaltic pump (602) for injecting the liquid in the liquid storage ring (4) into the reaction tank (5) or for draining the liquid in the liquid storage ring (4); a third peristaltic pump (603) for blowing air into a pipeline connecting the first injection pump (1) or the second injection pump (2) and the multi-channel valve (3) is connected to the liquid outlet of the first injection pump (1) and the second injection pump (2); a first reagent and a second reagent for ammonia nitrogen analysis are stored in the first injection pump (1) and the second injection pump (2), respectively; and a standard sample and a water sample for ammonia nitrogen analysis, as well as cleaning water, are connected to different channels of the multi-channel valve (3); The liquid outlet of the first injection pump (1) is connected to the second channel (302) of the multi-channel valve (3) via a first three-way connector (701), the liquid outlet of the second injection pump (2) is connected to the third channel (303) of the multi-channel valve (3) via a second three-way connector (702), and the third peristaltic pump (603) is connected to the first three-way connector (701) and the second three-way connector (702) respectively via a third three-way connector (703); One end of the liquid storage ring (4) is connected to the common port (300) of the multi-channel valve (3), and the other end of the liquid storage ring (4) is connected to the second peristaltic pump (602) and the overflow tank (907) respectively through the second three-way electromagnetic liquid valve (802); The first channel (301) of the multi-channel valve (3) is connected to the circulation port (506) of the reaction tank (5) and one end of the first peristaltic pump (601) through the fourth three-way connector (704), and the other end of the first peristaltic pump (601) is connected to the first waste liquid tank (901) and the first container (903) through the first three-way electromagnetic liquid valve (801). The fourth channel (304), the fifth channel (305), the sixth channel (306), the seventh channel (307), and the eighth channel (308) of the multi-channel valve (3) are respectively connected to the second waste liquid pool (902), the first container (903), the second container (904), the third container (905), and the fourth container (906); The first container (903) stores cleaning water, the second container (904) stores a first standard sample, the third container (905) stores a second standard sample, and the fourth container (906) stores a water sample; The first injection pump (1) and the second injection pump (2) are both step-by-step microinjection pumps; The stepping microinjection pump comprises a syringe (101), a fixing assembly for fixing the syringe (101) and a propulsion assembly for propelling a piston of the syringe (101); The fixing assembly comprises a base plate (102) and a support plate (103) provided on the base plate (102), wherein the support plate (103) is provided with a buckle (104) for fixing the syringe (101); The propulsion assembly includes a stepper motor (105) disposed on a base plate (102), and a slide (106) connected to the piston of the syringe (101); the rotating shaft of the stepper motor (105) is connected to a threaded screw (107); a threaded hole matching the threaded screw (107) is provided on the slide (106); when the rotating shaft of the stepper motor (105) rotates, the threaded screw (107) rotates in the threaded hole, driving the slide (106) to propel the piston of the syringe (101); The outer wall of the reaction pool (5) is covered with a heating wire (501), the reaction pool (5) is embedded with a temperature sensor (502), a detection light source (503) is provided on one side of the reaction pool (5), a light intensity detector (504) is provided on the other side of the reaction pool (5), and a cooler (505) is also provided on the outer wall of the reaction pool (5); a circulation port (506) is provided at the bottom of the reaction pool (5), and an overflow port (507) is also provided at the top of the reaction pool (5), and the overflow port (507) is connected to the overflow pool (907) through a pipeline.

2. The micro-reagent ammonia nitrogen online continuous analyzer according to claim 1, characterized in that, A support rod (108) is provided between the stepping motor (105) and the support plate (103), and a buckle (104) for fixing the syringe (101) is also provided on the support rod (108).

3. The micro-reagent ammonia nitrogen online continuous analyzer according to claim 2, characterized in that, A gasket (109) is provided on the side where the buckle (104) contacts the syringe (101).

4. The micro-reagent ammonia nitrogen online continuous analyzer according to claim 1, characterized in that, A pulley (110) is provided at the bottom of the slide (106). When the rotating shaft of the stepping motor (105) rotates, the slide (106) slides on the bottom plate (102) through the pulley (110); a magnetic ring limiter (111) is provided on the bottom plate (102) for sensing the sliding position of the pulley (110).

5. The micro-reagent ammonia nitrogen online continuous analyzer according to claim 1, characterized in that, A first pipeline water flow sensor (401) is provided at one end of the liquid storage ring (4) close to the multi-channel valve (3), and a second pipeline water flow sensor (402) is provided at one end of the liquid storage ring (4) close to the second peristaltic pump (602).

6. A method for online continuous analysis of ammonia nitrogen using the micro-reagent online continuous analyzer for ammonia nitrogen according to any one of claims 1 to 5, characterized in that: include: Step 1: measuring the initial absorbance of the empty reaction cell (5); pumping the water sample into the liquid storage ring (4) through the multi-channel valve (3) and the second peristaltic pump (602), then injecting the water sample in the liquid storage ring (4) into the reaction cell (5) through the multi-channel valve (3) and the second peristaltic pump (602), and measuring the initial blank absorbance of the water sample in the reaction cell (5); pumping the water sample in the reaction cell (5) into the liquid storage ring (4) through the multi-channel valve (3) and the second peristaltic pump (602), then emptying the water sample in the liquid storage ring (4) through the multi-channel valve (3) and the second peristaltic pump (602); Step 2: injecting a fixed amount of the first reagent and air into the liquid storage ring (4) through the first syringe pump (1), the third peristaltic pump (603) and the multi-channel valve (3), pumping a fixed amount of the water sample into the liquid storage ring (4) through the multi-channel valve (3) and the second peristaltic pump (602), and injecting a fixed amount of the second reagent and air into the liquid storage ring (4) through the second syringe pump (2), the third peristaltic pump (603) and the multi-channel valve (3), so that the second reagent, the water sample and the first reagent are stored in the liquid storage ring (4) in sequence with air as the interval; Step 3: The second reagent, the water sample, and the first reagent in the liquid storage ring (4) are sequentially injected into the reaction tank (5) through the multi-channel valve (3) and the second peristaltic pump (602) to perform a color development reaction; during the color development reaction, the water sample is pumped into the liquid storage ring (4) through the multi-channel valve (3) and the second peristaltic pump (602), and then the water sample in the liquid storage ring (4) is emptied through the multi-channel valve (3) and the second peristaltic pump (602), and step 2 is repeated; after the color development reaction is completed, step 4 is entered; Step 4: Measure the absorbance of the color-developing solution in the reaction tank (5), calculate the absorbance of the water sample based on the initial absorbance of the empty reaction tank (5), the initial blank absorbance of the water sample and the absorbance of the color-developing solution, and calculate the concentration of ammonia nitrogen in the water sample based on the absorbance of the water sample; drain the color-developing solution in the reaction tank (5) through the first peristaltic pump (601), pump the cleaning water into the reaction tank (5) through the first peristaltic pump (601), and drain the cleaning water in the reaction tank (5) through the first peristaltic pump (601); return to step 3 until the continuous analysis termination condition is reached, and enter step 5; Step 5: The cleaning water is pumped into the liquid storage ring (4) through the multi-channel valve (3) and the second peristaltic pump (602), the cleaning water in the liquid storage ring (4) is injected into the reaction tank (5) through the multi-channel valve (3) and the second peristaltic pump (602), the cleaning water in the reaction tank (5) is pumped into the liquid storage ring (4) through the multi-channel valve (3) and the second peristaltic pump (602), and the cleaning water in the liquid storage ring (4) is drained through the multi-channel valve (3) and the second peristaltic pump (602).

7. The method for online continuous analysis of ammonia nitrogen according to claim 6, wherein: The formula for calculating the absorbance of water samples is: ； in, represents the absorbance of the water sample, represents the absorbance of the color developing solution, represents the initial blank absorbance of the water sample, represents the correction factor, ,in, represents the initial absorbance of the empty reaction cell (5), Indicates the factory-calibrated absorbance of the empty reaction cell (5); Calculating the concentration of ammonia nitrogen in water samples based on the absorbance of water samples includes: Substitute the absorbance of the water sample into the ammonia nitrogen standard curve and calculate the concentration of ammonia nitrogen in the water sample according to the ammonia nitrogen standard curve; Among them, the ammonia nitrogen standard curve is obtained by analyzing ammonia nitrogen on several groups of standard samples with known ammonia nitrogen concentrations. The ammonia nitrogen standard curve is: ； in, represents absorbance, Indicates the concentration of ammonia nitrogen, represents the slope of the ammonia nitrogen standard curve, It represents the intercept of the ammonia nitrogen standard curve; Substitute the absorbance of the water sample into the ammonia nitrogen standard curve and calculate the concentration of ammonia nitrogen in the water sample: ； in, Indicates the concentration of ammonia nitrogen in the water sample.

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