Continuous monitoring method and continuous monitoring device

Abstract

The technical scheme of the present application provides a continuous monitoring device and a continuous monitoring method, which can improve the more accurate measurement of the low concentration of the target in the sample. The continuous monitoring device is used for continuously monitoring the concentration of the target in the external environment, and the continuous monitoring device comprises a sampling part, a liquid storage tank, a container, a detector and a processor. The sampling part collects the sample from the external environment, and the liquid storage tank stores the standard reagent containing the target with the first concentration. The container is in communication with the sampling part and the liquid storage tank, and a first specified amount of sample and a second specified amount of standard reagent are mixed to obtain a test reagent. The detector is in communication with the container, and detects the intensity signal reflecting the concentration of the target in the test reagent. The processor determines the concentration of the target in the sample according to the intensity signal.

Description

Technical Field

[0001] This invention relates to the field of environmental monitoring technology, and more specifically to a continuous monitoring device and a continuous monitoring method. Background Technology

[0002] Beer-Lambert law is the fundamental law of light absorption, describing the relationship between the intensity of light absorption by a substance at a specific wavelength and the concentration of the absorbing substance and the thickness of the liquid layer. The formula is as follows:

[0003] A = Kbc = lg(I0 / I) t )

[0004] Where A is absorbance, K is molar absorptivity, b is the thickness of the absorption layer, c is the concentration of the absorbing substance, I0 is the photometric intensity measured at the control solution (usually pure water), and I t The light intensity measured for the sample is calculated using the formula above, which is the standard method for measuring the concentration of target substances in water quality analysis.

[0005] Existing concentration monitoring methods based on Beer-Lambert's law can be applied to online continuous monitoring devices, such as online water quality monitoring devices or gas monitoring devices. Online water quality monitoring devices are placed near the monitoring point, automatically collecting water samples, measuring them, and uploading the data to a monitoring center. During continuous monitoring, the concentration of the target substance in the sample may fluctuate. Therefore, at certain times, the concentration of the target substance in the sample may be low, leading to incomplete color development of the solution, or the detection limit of the detection device may be high, making it impossible for the detection device to accurately identify and analyze the intensity change signal. Ultimately, this prevents the continuous monitoring device from accurately identifying low concentrations of the target substance in the sample. Therefore, how to construct a continuous monitoring device and method that can achieve accurate automated measurement even for samples with low target substance concentrations is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of the above-mentioned problems of the prior art, the present invention provides a continuous monitoring method and a continuous monitoring device, which can more accurately measure the concentration of low-concentration target substances in samples.

[0007] A first aspect of the present invention provides a continuous monitoring method for continuously monitoring the concentration of a target substance in an external environment, comprising the following steps:

[0008] The collection process involves collecting samples from the external environment.

[0009] The mixing step involves mixing a first specified amount of sample with a second specified amount of standard reagent to obtain the test reagent, wherein the standard reagent contains a first concentration of the target substance;

[0010] The detection step involves using a detector to detect the intensity signal reflecting the concentration of the target analyte in the test reagent;

[0011] The analysis procedure involves determining the concentration of the target analyte in the sample based on the intensity signal.

[0012] According to the technical solution of the present invention, by adding a first concentration of the target analyte to the standard reagent, the concentration of the target analyte in the sample can be increased. In this way, even if the concentration of the target analyte in the sample is low, the intensity change information of the test reagent can be accurately detected, and the accurate concentration of the target analyte in the test reagent can be obtained. Furthermore, during continuous monitoring of the sample, a first predetermined amount of sample and a second predetermined amount of standard reagent are drawn and mixed each time. This ensures that during continuous monitoring, the equivalent concentration of the target analyte diluted in the test solution from the standard reagent is the same in each test. Therefore, the accurate concentration of the target analyte in the sample can be obtained by simply subtracting a fixed concentration value from the detected concentration of the target analyte in the test solution. This makes it suitable for automated continuous monitoring processes without the need for unnecessary and complex calculations.

[0013] As a preferred technical solution, in the detection step, the detector's detection limit for the target analyte is a second concentration, where the second concentration is less than or equal to the first concentration.

[0014] According to this preferred technical solution, by setting the first concentration to be higher than the detector's detection limit for the target analyte, the low concentration of the target analyte in the sample can be replenished by adding the first concentration of the target analyte to the sample, so that the concentration of the target analyte in the test reagent is not less than the detector's detection limit during detection.

[0015] As a preferred technical solution, the analysis steps also include:

[0016] The concentration of the target substance corresponding to the test reagent is calculated based on the intensity signal. Then, the concentration of the target substance in the sample is obtained by subtracting the concentration of the target substance after dilution from the concentration of the target substance in the standard reagent.

[0017] According to this preferred technical solution, since a first predetermined amount of sample and a second predetermined amount of standard reagent are added each time, the concentration of the target substance in the standard reagent after dilution in the mixed solution is also fixed. Therefore, it is only necessary to calculate the overall concentration of the solution and then subtract a fixed value from the overall concentration to obtain the concentration of the target substance in the sample.

[0018] A second aspect of the present invention provides a continuous monitoring device for continuously monitoring the concentration of a target substance in an external environment. The continuous monitoring device includes a sampling unit, a storage tank, a container, a detector, and a processor. The sampling unit collects samples from the external environment. The storage tank stores standard reagents containing a first concentration of the target substance. The container is connected to both the sampling unit and the storage tank, and a first predetermined amount of sample is mixed with a second predetermined amount of standard reagent to obtain a test reagent. The detector is connected to the container and detects an intensity signal reflecting the concentration of the target substance in the test reagent. The processor determines the concentration of the target substance in the sample based on the intensity signal.

[0019] As a preferred technical solution, the detector's detection limit for the target analyte is a second concentration, where the second concentration is less than or equal to the first concentration.

[0020] As a preferred technical solution, the test reagent is further mixed with a reaction reagent and a colorimetric reagent, and the reaction product obtained by the reaction between the target and the reaction reagent is mixed with the colorimetric reagent to develop color.

[0021] According to this preferred technical solution, since the measurement of the concentration of the target substance in the solution based on the color change reaction requires the detection of the light intensity change (i.e., absorbance) of the solution to fit the concentration value from the absorbance-concentration curve, whether the light intensity change can be accurately measured determines the accuracy of the concentration detection. The continuous monitoring device provided by this invention can better improve the accuracy of continuous concentration monitoring based on the color change reaction.

[0022] As a preferred technical solution, the reaction reagent includes a reducing agent, and the reducing agent and the target substance at a first concentration are added to the same storage tank.

[0023] According to this preferred technical solution, adding the target substance at a first concentration to the reducing agent can reduce the risk of the target substance reacting with other reagents and facilitate the color reaction of the target substance with the color developer in the container.

[0024] As a preferred technical solution, the detector includes a light source, a sample cell, and a photoelectric sensor. The sample cell and the container are connected, and the light source and the photoelectric sensor are positioned opposite each other across the container.

[0025] According to this preferred technical solution, light is emitted by a light source, and a photoelectric sensor receives the light passing through the sample cell. It can detect the change in light intensity of the light passing through the test solution compared to the light passing through pure water, and thus calculate the concentration information of the target substance in the test solution based on the light intensity information.

[0026] As a preferred technical solution, the continuous monitoring device also includes a multi-port switching valve, which has a central valve port and multiple side valve ports. The multiple side valve ports are switchably connected to the central valve port. The sampling unit, the storage tank and the detector are connected to the side valve ports, and the container is connected to the central valve port.

[0027] According to this preferred technical solution, by automatically switching the multi-port switching valve, the reagents, standard solutions and samples in the storage tank can be supplied to the container for mixing. After mixing, the mixed test reagent is filled into the sample cell of the detector for detection, thereby realizing continuous and automatic concentration monitoring of the target analyte in the sample. The monitoring results are more accurate and save manpower. Attached Figure Description

[0028] Figure 1 This is a simplified structural diagram of a continuous monitoring device provided in an embodiment of the present invention.

[0029] Figure 2 This is a schematic diagram of a preferred continuous monitoring device provided by an embodiment of the present invention.

[0030] Figure 3 This is a flowchart of the continuous monitoring method provided by an embodiment of the present invention.

[0031] Figure 4 It is a comparison graph of absorbance-concentration curves obtained by continuous concentration detection of target substances according to existing technology and absorbance-concentration curves obtained by calculation.

[0032] Figure 5 This is a comparison chart of the detected absorbance-concentration curve and the calculated absorbance-concentration curve obtained after performing the continuous monitoring method using the continuous monitoring equipment provided in this embodiment.

[0033] Reference numerals: 1-Sampling unit; 11-Sampling port; 12-Sampling drive device; 2-Storage tank; 3-Container; 4-Detector; 41-Light source; 42-Sample cell; 43-Photoelectric sensor; 5-Processor; 6-Multi-port switching valve; 60-Eight-port switching valve; 61-Central valve port; 62-Side valve port; 7-Cleaning fluid supply device. Detailed Implementation

[0034] Some embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0035] The following description, with reference to the accompanying drawings, illustrates the continuous monitoring device for the concentration of target substances in samples provided by this invention. Figure 1 The diagram shown is a simplified structural diagram of a continuous monitoring device provided in an embodiment of the present invention. Figure 1 As shown, the continuous monitoring device includes a sampling unit 1, a storage tank 2, a container 3, a detector 4, and a processor 5.

[0036] The sampling unit 1 is used to collect samples from the external environment and mix them with reagents in the container 3. For example, for continuous water quality monitoring, the sampling unit 1 may have a sampling port 11 and a sampling drive device 12. The sampling port 11 is placed in the water source of the external environment. Driven by the sampling drive device 12, water samples from the external environmental monitoring point can be collected in real time, at specified intervals, or continuously. In some other embodiments, the sampling unit 1 may also be a gas sampling port for collecting air samples from the external environmental monitoring point for testing.

[0037] Preferably, the sampling unit 1 may also have a pretreatment device (not shown in the figure) disposed between the sampling port 11 and the container 3. The pretreatment device may include a filtration device, a heating and cooking device and / or a physical sedimentation device, which can pretreat the water sample to be tested by filtration, high temperature or sedimentation, thereby removing insoluble impurities in the water sample.

[0038] The continuous monitoring equipment can have multiple storage tanks 2 built into its chassis. These tanks store the same or different standard reagents or reaction reagents. Preferably, for the continuous water quality monitoring equipment, the multiple storage tanks 2 can store reaction reagents and colorimetric reagents, respectively. The reaction reagents can be reducing agents, oxidizing agents, and / or masking agents, etc. All storage tanks 2 are connected to a container 3, allowing reagents to be supplied to the container 3. In the continuous monitoring equipment provided in this embodiment, the standard reagents stored in the storage tanks 2 also contain a first concentration of the target substance. The standard reagent containing the target substance can be added to any of the storage tanks 2, or it can be placed separately in a storage tank 2 for supply to the container 3; this is not limited. Preferably, adding the standard reagent with the first concentration of the target substance to the storage tank 2 containing the reducing agent can reduce the risk of the target substance reacting with other reagents and facilitates the subsequent introduction of the target substance into the container 3 for a colorimetric reaction with the colorimetric reagent within the container 3.

[0039] Container 3 is connected to both sampling unit 1 and storage tank 2, and is used to obtain a first predetermined amount of sample and a second predetermined amount of standard reagent, and to mix the sample and standard reagent to obtain the test reagent. Therefore, preferably, container 3 can be a quantitative container 3 capable of quantitative extraction, such as a graduated piston extraction container 3. It should be noted that in this embodiment, the first predetermined amount and the second predetermined amount refer to the mass or volume of the sample and standard reagent, which is not limited here. Taking a continuous water quality monitoring device as an example, a volumetric pump or piston pump can generally be used to quantitatively extract the volume of the sample solution and the standard reagent solution.

[0040] Detector 4 can be a light intensity detector 4 or other detection device capable of acquiring intensity information. Taking light intensity detector 4 as an example, detector 4 can include a sample cell 42, a light source 41, and a photoelectric sensor 43. The sample cell 42 can be a container of any shape with light-transmitting properties, preferably formed as a transparent detection box with a regular shape and uniform thickness. The transparent detection box is connected to container 3 and can receive the test reagent from container 3. In some embodiments, the continuous monitoring device can also include an air injection mechanism (not shown in the figure) for injecting air into the transparent detection box, so that the liquid is efficiently mixed under the drive of bubbles. In other embodiments, a heat preservation device (not shown in the figure) can also be set near the transparent detection box to heat and keep the liquid in the transparent detection box, which can further accelerate the mixing and reaction rate.

[0041] The light source 41 and the photoelectric sensor 43 are arranged opposite each other across the sample cell 42. Light of a certain wavelength emitted by the light source 41 passes through the sample cell 42 and is received by the photoelectric sensor 43, thereby realizing the measurement of the photometric intensity of the mixed test reagent in the sample cell 42.

[0042] Specifically, in some embodiments of the present invention, the detection limit of the detector 4 for the target analyte is a second concentration, and the concentration of the target analyte in the standard reagent is a first concentration, which is not less than the second concentration. In other embodiments of the present invention, the concentration of the target analyte in the test reagent (a mixture of a first specified amount of sample and a second specified amount of standard reagent) is a third concentration, which is not less than the second concentration. In other words, the concentration of the target analyte in the standard reagent itself is greater than the detection limit, and the concentration of the target analyte in the test reagent obtained after mixing the standard reagent and the sample is also greater than the detection limit. Thus, by adding the standard reagent, the detector 4 ensures accurate detection of the test reagent.

[0043] The processor 5 can perform a curve fitting program based on the intensity information detected by the detector 4 to determine the concentration of the target substance in the sample.

[0044] Specifically, when it is necessary to measure the concentration of a target substance in a sample, the standard reagent and sample can be quantitatively extracted from multiple storage tanks 2. After the first specified amount of sample and the second specified amount of standard reagent are extracted into container 3, they are mixed to obtain the test reagent. The test reagent enters the sample cell 42 of the detector 4. After continuous mixing and reaction in the sample cell 42, the light source 41 emits light of a certain wavelength. The photoelectric sensor 43 receives the light intensity signal of the light transmitted through the sample cell 42. After receiving the light intensity signal, the processor 5 fits the light intensity signal with the standard curve stored in the memory to obtain the concentration information of the target substance in the test solution. Since the sample extracted each time is the first specified amount and the standard reagent is the second specified amount, the amount of the target substance added in the standard reagent after dilution is also the same each time. Therefore, the accurate concentration information of the target substance in the sample can be obtained by simple calculation.

[0045] In this embodiment, by adding a first concentration of the target analyte to the standard reagent, and ensuring that this first concentration is not less than the detection limit of the detector 4 for the target analyte, a certain amount of the target analyte can be added to the sample, thereby ensuring that the concentration of the target analyte in the final test reagent is not less than the detection limit of the detector 4. In this way, even if the concentration of the target analyte in the sample is lower than the detection limit of the detector 4, the intensity change information of the test solution can still be accurately detected, and the accurate concentration of the target analyte in the test solution can be obtained.

[0046] Furthermore, during continuous monitoring of the sample, a second specified amount of standard reagent is drawn and mixed with the first specified amount of sample each time. This ensures that during continuous monitoring, the concentration of the target substance diluted with the test reagent in the standard reagent is the same each time. Therefore, the accurate concentration of the target substance in the sample can be obtained by subtracting a fixed value from the concentration of the target substance in the test solution obtained by the test. No complicated calculations are required, making it more suitable for long-term and multiple monitoring by continuous monitoring equipment.

[0047] For cases where the concentration of the target analyte in the sample is particularly low, close to 0, the concentration of the target analyte in the test reagent can be further adjusted by adjusting the first concentration and / or the ratio of the first specified amount and the second specified amount, so that the concentration of the target analyte in the test reagent reaches a third concentration and that the third concentration is not less than the second concentration. This further ensures that the concentration of the target analyte in the test reagent detected by the detector 4 will not be lower than the detection limit of the detector 4, ensuring the accuracy of the intensity signal detected by the detector 4, that is, further ensuring the accuracy of the obtained target analyte concentration information.

[0048] It should be noted that in this embodiment, an online water quality monitoring device based on color reaction is used as an example for illustration. However, the application field of the technical solution provided by the present invention is not limited to this. It can also be applied to the continuous monitoring of liquid turbidity, or to the measurement of some gases. For example, for the measurement of some gases, air is passed into the reaction liquid to react. After the target substance in the air reacts with the reaction liquid, it causes the reaction liquid to change color or become turbid. Thus, the detector 4 detects the change in intensity signal to obtain the concentration of the target substance in the air. All of the above are within the protection scope of the present invention.

[0049] Figure 2 A schematic diagram of a preferred continuous monitoring device is shown. Figure 2 As shown, the continuous monitoring device also includes a multi-port switching valve 6. The multi-port switching valve 6 has a central valve port 61 and multiple side valve ports 62. The multiple side valve ports 62 are switchably connected to the central valve port 61. The sampling unit 1, the storage tank 2, and the detector 4 are connected to the side valve ports 62, and the container 3 is connected to the central valve port 61. Specifically, an eight-port switching valve 60 can be used. The eight-port switching valve 60 has eight side valve ports 62 on its sides, which are respectively connected to the sampling unit 1, the reduction storage tank 2 (containing the target substance), the oxidation storage tank 2, the colorimetric storage tank 2, the detector 4, the air inlet, the cleaning fluid inlet, and the outlet. The central valve port 61 of the eight-port switching valve 60 is connected to the container 3. Thus, through the automatic switching of the eight-port switching valve 60, the sample, reducing agent, oxidizing agent, and colorimetric agent can all be introduced into the container 3 for mixing to obtain the test reagent. After mixing, the test reagent in the container 3 is introduced into the detector 4 for detection. After the test is completed, the test solution in the detector 4 is discharged from the outlet. The cleaning solution supply device 7 then introduces cleaning solution into the eight-way switching valve 60, switches the eight-way switching valve 60 to clean, and finally discharges the cleaning solution. Then the concentration of the target substance in the sample can be detected again.

[0050] In this embodiment, the automatic switching of the multi-port switching valve 6 can automatically switch the process of supplying the standard solution and sample to the container 3 for mixing, and filling the sample cell 42 of the detector 4 with the mixed test reagent for detection. This enables continuous and automatic concentration monitoring of the target analyte in the sample, and the detection results are more accurate and save manpower.

[0051] The continuous monitoring device provided in this embodiment can be, for example, a continuous monitoring device for monitoring the concentration of metal ions in water. Further, the continuous monitoring device can be, for example, a continuous monitoring device for monitoring the total chromium content, hexavalent chromium content, total nickel content, total copper content, or total manganese content in water.

[0052] In some embodiments, the continuous monitoring device can be a continuous monitoring device for measuring the hexavalent chromium content in industrial wastewater. This continuous monitoring device can use the diphenylcarbazide spectrophotometric method for measurement, and specific measurement methods can adopt, for example, the measurement schemes in standard documents GB 7467-87 and HJ 609-2019. The storage tank 2 can store chromium standard solution, sulfuric acid solution, and diphenylcarbazide solution; in some embodiments, a suitable masking agent can also be selected according to the water quality conditions.

[0053] In some embodiments, the continuous monitoring device can be a continuous monitoring device for measuring the total chromium content in industrial wastewater. This continuous monitoring device can use the sodium persulfate oxidation-diphenylcarbazide spectrophotometric method for measurement, and the specific measurement method can adopt the measurement scheme in the standard document GB / T15555.5-1995. The storage tank 2 can store chromium standard solution, sodium persulfate solution, sulfuric acid solution, and diphenylcarbazide solution.

[0054] In some embodiments, the continuous monitoring equipment can be a continuous monitoring device for measuring the total copper content in industrial wastewater. This continuous monitoring equipment can use methods such as the 2,9-dimethyl-1,10-phenanthroline spectrophotometric method, the sodium diethyldithiocarbamate spectrophotometric method, the dicyclohexanone oxaloyl dihydrazone spectrophotometric method, and the methyl methacrylate spectrophotometric method to measure total copper. Specific measurement methods can refer to the measurement schemes in standard documents such as HJ 486—2009 and HJ 485—2009. Taking the methyl methacrylate spectrophotometric method as an example, the storage tank 2 can store a copper standard solution (e.g., copper sulfate standard solution), sulfuric acid solution, sodium persulfate solution, hydroxylamine hydrochloride solution, and disodium methyl methacrylate disulfonate solution. The sodium persulfate solution acts as an oxidant, used to oxidize and decompose the organic matter in the sample, allowing copper to enter the solution in ionic form. The hydroxylamine hydrochloride solution and sulfuric acid solution act as reducing agents, used to reduce copper ions to cuprous ions and provide an acidic environment. The disodium disulfonate solution of ketone is used as a colorimetric agent to react cuprous ions with ketone to form a colored complex. The concentration of copper ions can then be determined by spectrophotometry at 475 nm. In some embodiments, the storage tank 2 may also store a masking agent, such as a trisodium citrate solution of a certain concentration.

[0055] The above is merely an exemplary description of the applicable scope of the technical solution of the continuous monitoring device of this application. In other embodiments of the present invention, the continuous monitoring device may also be a continuous monitoring device for monitoring other parameters, such as a continuous monitoring device for monitoring parameters such as total phosphorus, total sulfur, and volatile organic compounds, which will not be elaborated here.

[0056] In this embodiment, the processor 5 can be a component of a processing terminal, such as a computer processor, or a computing processing device directly installed inside the continuous monitoring device. There are no limitations on this. The processor 5 can control the aforementioned mechanisms and container 3 to perform corresponding operations and functions. Furthermore, the processor 5 can be configured to execute code or instructions to control the aforementioned mechanisms to perform corresponding operations and functions. The processor 5 can be a general-purpose processor, processor core, multiprocessor, reconfigurable processor, microcontroller, digital signal processor (DSP), application-specific integrated circuit (ASIC), graphics processing unit (GPU), field-programmable gate array (FPGA), programmable logic device (PLD), controller, state machine, gated logic, discrete hardware component, any other processing unit, or any combination or multiple thereof. The processor 5 can be a single processing unit, multiple processing units, a single processing core, a dedicated processing core, a coprocessor, or any combination thereof. According to a specific embodiment, the processor 5 can be a virtualized computer running within one or more other computing machines.

[0057] Preferably, the continuous monitoring device may also include a memory for storing a standard curve between intensity information and the concentration of the target analyte. The memory may comprise non-volatile memory, such as read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), flash memory (FLASH), or any other means capable of storing program instructions or data with or without applied power. The memory 7 may also include volatile memory, such as random access memory (RAM), static random access memory (SRAM), dynamic random access memory (DRAM), and synchronous dynamic random access memory (SDRAM). Other types of RAM may also be used to implement the memory. The memory may be implemented using a single memory module or multiple memory modules. Although the memory is depicted as part of a computer, those skilled in the art will recognize that the memory can be separated from the computer without departing from the scope of the subject matter.

[0058] The following section provides a further description of a continuous monitoring method provided by the present invention, based on the aforementioned continuous monitoring equipment and specific embodiments.

[0059] This embodiment provides a continuous monitoring method applicable to continuous monitoring instruments with the above-described structure, or to other analytical monitoring instruments capable of detecting and analyzing the concentration of a target substance based on the intensity signal of the solution.

[0060] Figure 3 This is a flowchart of the continuous monitoring method provided by an embodiment of the present invention, such as... Figure 3As shown, the continuous monitoring method for target substance concentration provided in this embodiment includes the following steps:

[0061] S1, collecting samples from the external environment;

[0062] In mixing step S2, a first specified amount of sample is mixed with a second specified amount of standard reagent to obtain the test reagent, wherein the standard reagent contains a first concentration of the target substance;

[0063] In detection step S3, detector 4 is used to detect the intensity signal reflecting the concentration of the target substance in the test reagent. The detection limit of detector 4 for the target substance is the second concentration, which is less than or equal to the first concentration.

[0064] In analysis step S4, the concentration of the target analyte in the sample is determined based on the intensity signal.

[0065] Specifically, when it is necessary to continuously measure the concentration of a target analyte in a sample online, firstly, the acquisition step S1 is performed to collect a sample from the external environment. Then, the mixing step S2 is performed to quantitatively extract standard reagents and samples from multiple storage tanks 2. After a first specified amount of sample and a second specified amount of standard reagent are extracted into container 3, they are mixed to obtain the test solution. Then, the detection step S3 is performed to pass the test solution into the sample cell 42 of detector 4. After continuous mixing and reaction, light source 41 emits light, and photoelectric sensor 43 receives the light emitted by light source 41 that passes through sample cell 42 and detects the absorbance.

[0066] Finally, in analysis step S4, after receiving the light intensity signal, the processor 5 fits the light intensity signal with the standard curve stored in the memory to obtain the concentration information of the target substance in the test solution, and then calculates the concentration information of the target substance in the sample.

[0067] It should be noted that this embodiment illustrates the case where the collection step S1 is performed first and the mixing step S2 is performed later. However, the present invention is not limited to this. For example, the collection step S1 and the mixing step S2 can be performed simultaneously, that is, the sample and reagent are extracted into the container 3 at the same time as the sample is collected. This is also applicable to the present invention.

[0068] Preferably, the analysis step S4 further includes: calculating the concentration of the target substance corresponding to the test reagent based on the intensity signal, and then subtracting the concentration of the target substance after dilution of the target substance in the standard reagent from the concentration of the target substance to obtain the concentration of the target substance in the sample.

[0069] Specifically, in analysis step S4, the concentration A of the target analyte corresponding to the test reagent is first obtained by fitting the intensity signal with the standard curve. 总Calculate the total amount of target class substances of the first concentration A1 in the standard reagent of the second specified amount V2, and then calculate the concentration A of this portion of target substances after mixing with the sample solution of the first specified amount V1 and diluting it. 标 for:

[0070]

[0071] Finally, the formula for calculating the concentration A of the target analyte in the sample is as follows:

[0072] A = A 总 -A 标

[0073] In some implementations, for A 标 In cases where this can be determined in advance, A can be included in the standard curve. 标 The concentration of the target substance can be obtained by subtracting it, through curve fitting or a database or table lookup.

[0074] The following are examples of using the continuous monitoring equipment provided in this embodiment to perform a continuous monitoring method to test the total copper content in a sample.

[0075] The sample used in this embodiment is copper sulfate solution, the oxidant is sodium persulfate, the reducing agent is hydroxylamine hydrochloride and sulfuric acid, the masking agent is trisodium citrate, and the colorant is disodium disulfonate solution of ketone sulfonate (CAS No.: 52698-84-7). The preparation methods of each reagent are shown in Table 1.

[0076] Table 1. Reagent Preparation Methods

[0077]

[0078]

[0079] First, as a comparative experiment, the copper standard stock solution was diluted with pure water to obtain nine standard samples with copper concentrations as shown in Table 2. 3.006 mL of each standard sample was taken, and 0.150 mL of acidic sodium persulfate solution was added. The mixture was then digested at high temperature for at least 10 minutes. Next, 0.374 mL of a common reducing agent was added to the mixture to reduce the divalent copper in the standard sample to cuprous ions. Then, 0.800 mL of trisodium citrate was added to mask interfering factors and adjust the pH of the solution to neutral or slightly acidic. Finally, 1.200 mL of the colorimetric reagent, disodium disulfonate solution, was added. After reacting for 5 minutes, the solution was passed through a light intensity detector for detection. The measured values ​​are shown in Table 2.

[0080] Table 2. Measurement Record of Total Copper Absorbance with Common Reducing Agent

[0081]

[0082]

[0083] The actual absorbance-concentration curve obtained by fitting the detection results is compared with the calculated absorbance-concentration curve. For example... Figure 4 As shown, the data obtained using the standard method of existing technology reveals that the actual curve deviates significantly from the calculated curve in the low concentration region. Particularly at concentrations below 0.2 mg / L, the absorbance of the emitted color is much lower than the calculated linear curve. This is because the change in light intensity (absorbance) at this point is very subtle, and the change in refractive index caused by the change in liquid color is too small. Considering the influence of noise such as liquid convection, this change cannot be accurately detected by the photoelectric sensor 43.

[0084] In an embodiment of the present invention, a copper standard stock solution was added to a common reducing agent to prepare a standard reducing agent with a copper concentration of 0.3 mg / L, and the standard reducing agent was used to completely replace the original common reducing agent in the experimental reaction.

[0085] Specifically, the testing process of the embodiment of the present invention is as follows: First, the copper standard stock solution is diluted with pure water to obtain 15 standard samples with copper concentrations of target substances as shown in Tables 2 and 3. Take 3.006 mL of each concentration of standard sample, add 0.150 mL of acidic sodium persulfate solution, and digest the mixed solution at high temperature for at least 10 minutes; then add more than 0.374 mL of standard reducing agent to the mixed solution, then add 0.800 mL of trisodium citrate, and finally add 1.200 mL of colorimetric reagent disodium disulfonate solution. After reacting for 5 minutes, the solution to be tested is passed into a light intensity detector for detection, and the detected values ​​are shown in Table 3.

[0086] Table 3. Measurement Record of Total Copper Absorbance of Standard Reducing Agent

[0087]

[0088]

[0089] The actual absorbance-concentration curve obtained by fitting the detection results is compared with the calculated absorbance-concentration curve. For example... Figure 5 As shown, a standard reducing agent with a copper concentration of 0.3 mg / L was obtained by adding copper standard stock solution to a common reducing agent. Experiments were conducted and detected using this standard reducing agent. It can be seen that even in the low concentration range, absorbance and concentration still maintained good linearity and resolution. Therefore, through comparison and calculation, it can be seen that the continuous monitoring equipment and continuous monitoring method of this application can effectively improve the detection accuracy of the continuous monitoring equipment in the low concentration range.

[0090] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.

[0091] The technical solutions of the present invention have been described in conjunction with the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions resulting from such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A continuous monitoring method for continuously monitoring the concentration of a target substance in an external environment, characterized in that, Includes the following steps: The collection step involves collecting samples from the external environment; The mixing step involves mixing a first predetermined amount of the sample with a second predetermined amount of standard reagent to obtain a test reagent, wherein the standard reagent contains a first concentration of the target substance; The detection step involves using a detector to detect an intensity signal reflecting the concentration of the target analyte in the test reagent; The analysis step involves determining the concentration of the target analyte in the sample based on the intensity signal.

2. The continuous monitoring method according to claim 1, characterized in that, In the detection step, the detector's detection limit for the target analyte is a second concentration, where the second concentration is less than or equal to the first concentration.

3. The continuous monitoring method according to claim 1, characterized in that, The analysis step also includes: The concentration of the target substance corresponding to the test reagent is calculated based on the intensity signal, and then the concentration of the target substance after dilution in the standard reagent is subtracted from the concentration of the target substance to obtain the concentration of the target substance in the sample.

4. A continuous monitoring device for continuously monitoring the concentration of a target substance in an external environment, characterized in that, include: The sampling unit collects samples from the external environment; A storage tank containing standard reagents, wherein the standard reagents contain a first concentration of the target substance; The container is connected to both the sampling unit and the storage tank, and a first predetermined amount of the sample is mixed with a second predetermined amount of the standard reagent to obtain the test reagent; A detector, connected to the container, detects an intensity signal reflecting the concentration of the target substance in the test reagent; The processor determines the concentration of the target analyte in the sample based on the intensity signal.

5. The continuous monitoring device according to claim 4, characterized in that, The detector's detection limit for the target analyte is a second concentration, where the second concentration is less than or equal to the first concentration.

6. The continuous monitoring device according to claim 4, characterized in that, The test reagent also contains a reaction reagent and a colorimetric reagent. The reaction product obtained by the reaction between the target analyte and the reaction reagent is mixed with the colorimetric reagent to develop a color.

7. The continuous monitoring device according to claim 6, characterized in that, The reaction reagent includes a reducing agent, and the reducing agent and the target substance at the first concentration are added to the same storage tank.

8. The continuous monitoring device according to claim 4, characterized in that, The detector includes a light source, a sample cell, and a photoelectric sensor. The sample cell is connected to the container, and the light source and the photoelectric sensor are positioned opposite each other across the container.

9. The continuous monitoring device according to claim 4, characterized in that, Also includes: A multi-port switching valve has a central valve port and multiple side valve ports, all of which are switchably connected to the central valve port. The sampling unit, the liquid storage tank, and the detector are connected to the side valve ports, and the container is connected to the central valve port.

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