A method and system for detecting cations and anions that can self-check the system stability

Abstract

The present invention relates to the technical field of ion chromatography detection, and specifically relates to a method for detecting anions and cations that can self-check the system stability. It can self-check the system stability, effectively monitor the performance of the analysis process, timely identify and correct potential problems, improve the overall analysis and detection quality, is convenient to operate, and improves the detection efficiency; when it is necessary to monitor the system stability, a quality control sample with a determined concentration is introduced for determination, and according to the linear error between the quality control sample and the calibration curve, it is judged whether the system instrument is currently stable. There is no need to frequently verify and update the calibration curve. The detection method is convenient and easy to operate, ensuring the analysis performance of the system and the accuracy of the subsequent sample detection and analysis results. The present application also provides a detection system that can realize the online automatic preparation of standard samples in the calibration curve, reduce manual operation pollution and errors, avoid the adverse impact of the dead volume of the existing preparation instrument on the concentration accuracy, is convenient to operate, and has a high preparation efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of ion chromatography detection, and particularly relates to a method and a detection system for detecting anions and cations that can self-check the stability of the system. Background Art

[0002] Ion chromatography detection is a high-performance liquid chromatography technology based on the principle of ion exchange, mainly used for separating, identifying, and quantifying ions and ionic compounds in samples. During the ion chromatography detection process, the calibration curve is used to establish the mathematical relationship between the concentration of the target ions in the sample and the response signals (such as peak area, peak height, etc.) generated in the chromatographic analysis, which is crucial for accurately determining the concentration of ions in the sample; however, the calibration curve is not immutable and needs to be verified and updated to ensure the continuous accuracy of the quantitative results. However, frequent verification or calibration of the calibration curve requires a relatively long determination time, with cumbersome operations and low work efficiency. At the same time, the stability monitoring of the ion chromatography detection system is an important link to ensure the reliable performance of the instrument and accurate data; therefore, providing a method and a system for detecting anions and cations that can self-check the stability of the system, which can reduce the frequency of frequent updates of the calibration curve and ensure the stability and accuracy of the operation of the detection system, has important significance. Summary of the Invention

[0003] The purpose of the present invention is to provide a method and a detection system for detecting anions and cations that can self-check the stability of the system, so as to solve the existing technical problems in the above background art.

[0004] To solve the above technical problems, the technical solutions provided by the present invention are as follows:

[0005] On the one hand, the present application provides a method for detecting anions and cations that can self-check the stability of the system, including the following steps:

[0006] Online preparation of the standard sample solution: According to the preset concentration of the standard sample solution, take the required volumes of pure water and the stock standard solution respectively and mix them evenly, and obtain a standard sample solution with a determined concentration after online dilution;

[0007] Determination of the calibration curve: Detect the standard sample solution obtained in the previous step to obtain the corresponding conductivity detection value; repeat the preparation and determination of the standard sample solutions with different concentrations to complete the numerical detection required for the calibration curve and the drawing of the calibration curve;

[0008] Pretreatment and detection of the sample to be tested: Pretreat the sample to be tested that actually needs to be detected to remove the impurities and gases contained in the sample to be tested; then detect the treated sample to be tested to obtain the corresponding conductivity detection value, form a chromatogram and perform subsequent quantitative calculations;

[0009] Introduction and determination of quality control samples: Introduce quality control samples with determined concentrations for testing, and self-check the system stability according to the judgment conditions to determine whether to continue testing the samples to be measured or calibrate the system.

[0010] Based on the above technical solution, the judgment condition is that the concentration measurement result of the quality control sample conforms to the expected concentration value and its response value is within the linear range of the calibration curve; if the judgment condition is met, it indicates that the system is stable and the testing of the samples to be measured can continue. If the judgment condition is not met, it indicates that the system is unstable or faulty, and it is necessary to re-determine the calibration curve or perform system maintenance.

[0011] Based on the above technical solution, the introduction timing of the quality control sample is before the testing of different batches of samples to be measured, during the testing of the same batch of samples to be measured, or after the testing of different batches of samples to be measured.

[0012] Based on the above technical solution, the online preparation method of the standard sample solution includes the following steps:

[0013] Step 1: Rinse with the standard sample mother liquor; rinse the pipeline with the standard sample mother liquor until the pipeline is filled with the standard sample mother liquor and then complete the rinsing.

[0014] Step 2: Rinse with pure water; rinse the inside of the pipeline with pure water until the pipeline is filled with pure water and then complete the rinsing. At this time, except for the pipeline connected to the standard sample mother liquor, other pipelines are filled with pure water, which is the initial state of the pipeline.

[0015] Step 3: Add the standard sample mother liquor; introduce the standard sample mother liquor into the pipeline and add the required amount of the standard sample mother liquor into the dilution container. At this time, there will be a dead volume of the standard sample mother liquor remaining in the pipeline.

[0016] Step 4: Add pure water; introduce pure water into the pipeline and add the required amount of pure water into the same dilution container as in Step 3. The pure water will flush the dead volume of the standard sample mother liquor remaining in Step 3 into the same dilution container. After closing the pure water, except for the pipeline connected to the standard sample mother liquor, other pipelines are filled with pure water. At this time, the required amount of the standard sample mother liquor and pure water are collected in the dilution container, and an online dilution process of the standard sample mother liquor is completed to obtain a standard sample solution with a preset concentration. At the same time, the pipeline reaches the initial state in Step 2.

[0017] Step 5: Repeat the above Steps 3 and 4 again to prepare the standard sample solution with the next different concentration, and realize the online automatic preparation of the standard sample solutions with different concentrations.

[0018] Based on the above technical solution, the quality control sample is prepared by the online preparation method of the standard sample solution.

[0019] On the other hand, the present application provides a cation and anion detection system capable of self-checking system stability. The detection system executes the above-mentioned cation and anion detection method capable of self-checking system stability. The detection system includes an online standard sample preparation device, a sample pretreatment device, a sample selection device, and an ion chromatography detection device. The end of the online standard sample preparation device and the end of the sample pretreatment device are both connected to the head end of the sample selection device, and the end of the sample selection device is connected to the ion chromatography detection device.

[0020] Based on the above technical solution, the online standard sample preparation device includes at least one set of solution dilution assemblies. Each solution dilution assembly includes a standard sample mother liquid bottle, a first selection valve, a metering pump, and a dilution container. The head end of the first selection valve is connected to the standard sample mother liquid bottle through a mother liquid pipeline and to a pure water tank through a pure water pipeline, and the tail end is connected to the head end of the metering pump through a first pipeline. The tail end of the metering pump is connected to the dilution container through a second pipeline.

[0021] Based on the above technical solution, the sample pretreatment device includes a sample bottle, a filter, and a degassing mechanism. The head end of the filter is communicated with the sample bottle through a sample pipeline, and the tail end is communicated with the head end of the degassing mechanism. The tail end of the degassing mechanism is connected to the sample selection device.

[0022] Based on the above technical solution, the sample selection device includes at least one injection selection valve. The head end of the injection selection valve is respectively connected to the ends of the online standard sample preparation device and the sample pretreatment device, and the tail end is connected to the head end of the ion chromatography detection device.

[0023] Based on the above technical solution, the ion chromatography detection device includes at least one set of ion chromatography detection components. Each ion chromatography detection component includes a first multi-port valve, an eluent generator, a chromatographic column, a suppressor, and a conductivity detector. The head end of the first multi-port valve is respectively connected to the sample selection device and the eluent generator, and the tail end is connected to the chromatographic column. The suppressor and the conductivity detector are sequentially arranged at the tail end of the chromatographic column. The eluent generator is connected to an infusion pump through a pipeline, and the inlet of the infusion pump is communicated with the pure water tank.

[0024] The beneficial effects of the technical solution provided by the present invention are as follows:

[0025] 1. The present invention provides a cation and anion detection method capable of self-checking the system stability, which can self-check the system stability, effectively monitor the performance of the analysis process, timely identify and correct potential problems, improve the overall analysis and detection quality, is convenient to operate, saves time and effort, and improves the detection efficiency; when it is necessary to monitor the system stability, a quality control sample with a determined concentration is introduced for determination, and according to the linear error between the quality control sample and the calibration curve, it is judged whether the system instrument is stable at present. If it is in a stable state, the sample detection can be continued. When it is unstable, the calibration curve is determined or the system is checked and maintained, etc.; it is not necessary to frequently verify and update the calibration curve, that is, after detecting multiple samples to be measured or after the system has run for a period of time, only a quality control sample with a determined sample concentration needs to be introduced for determination and then self-checked. The detection method is convenient and easy to operate, improves the detection efficiency, and while monitoring the operation stability of the detection system, ensures the analysis performance of the system and the accuracy of the subsequent sample detection and analysis results.

[0026] 2. The present application also provides a detection system. In particular, by setting up an on-line standard sample preparation device, the on-line automatic preparation of the standard sample solution used in the calibration curve can be realized. It is not necessary to use the method of manual operation or manual cooperation with the preparation instrument in the prior art to prepare, store and then use the standard sample. The working efficiency is high and the storage steps are reduced. At the same time, the concentration preparation accuracy of the standard sample solution is high and the consistency is good, avoiding the adverse impact of the dead volume existing in the preparation instrument on the solution concentration accuracy, and ensuring the subsequent high detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a flow schematic diagram of the detection method in the present invention;

[0028] Figure 2 is a logic block diagram of step one of the on-line preparation method of the standard sample solution in the present invention;

[0029] Figure 3 is a logic block diagram of step two of the on-line preparation method of the standard sample solution in the present invention;

[0030] Figure 4 is a logic block diagram of step three of the on-line preparation method of the standard sample solution in the present invention;

[0031] Figure 5 is a logic block diagram of step four of the on-line preparation method of the standard sample solution in the present invention;

[0032] Figure 6 is a structural schematic diagram of the detection system in the present invention;

[0033] Figure 7 is a structural schematic diagram of the on-line standard sample preparation device in the present invention;

[0034] Figure 8 It is a schematic structural diagram of the ion chromatography detection device in the present invention; Specific embodiments

[0035] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0036] In the present invention, unless otherwise clearly defined and limited, terms such as "installation", "connection", "connection", "fixation" and other terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be directly connected, or indirectly connected through an intermediate medium, and can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "left", "right", "front", "rear", "top", "bottom", etc. are all based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0038] As Figures 1 to 8 shown, the present application provides a method for detecting anions and cations that can self-check the system stability, including the following steps:

[0039] Online preparation of standard sample solution: According to the preset concentration of the standard sample solution, take the required volumes of pure water and the stock solution of the standard sample respectively and mix them evenly, and obtain a standard sample solution with a determined concentration after online dilution;

[0040] Determination of calibration curve: Detect the standard sample solution obtained in the previous step to obtain the corresponding conductivity detection value; Repeat the preparation and determination of standard sample solutions with different concentrations to complete the numerical detection required for the calibration curve and the drawing of the calibration curve;

[0041] Pretreatment and detection of the sample to be tested: Pretreat the sample to be tested that actually needs to be detected to remove the impurities and gases contained in the sample to be tested; Then detect the treated sample to be tested to obtain the corresponding conductivity detection value, form a chromatogram and perform subsequent quantitative calculations;

[0042] Introduction and determination of quality control samples: Introduce quality control samples with a determined concentration for detection, self-check the system stability according to the judgment conditions, and judge whether to continue the detection of the sample to be tested or perform system calibration.

[0043] The present invention provides a method for detecting cations and anions that can self-check the system stability. It can self-check the system stability, effectively monitor the performance of the analysis process, promptly identify and correct potential problems, improve the overall analysis and detection quality, is convenient to operate, saves time and effort, and improves the detection efficiency. Before detecting the sample to be tested, a calibration curve is measured first, and then the sample to be tested is detected. When it is necessary to monitor the system stability, a quality control sample with a determined concentration is introduced for measurement. According to the linear error between the quality control sample and the calibration curve, it is judged whether the system instrument is stable at present. If it is in a stable state, the sample detection can continue; if it is unstable, the calibration curve is measured again or the system is checked and maintained, etc. It is not necessary to frequently verify and update the calibration curve, that is, after detecting multiple samples to be tested or after the system has run for a period of time, only a quality control sample with a determined sample concentration is introduced for measurement and then self-checked. The detection method is convenient and easy to operate, improves the detection efficiency, and while monitoring the operation stability of the detection system, ensures the analysis performance of the system and the accuracy of the subsequent sample detection and analysis results.

[0044] Based on the above technical solution, the judgment condition is that the measured result of the concentration of the quality control sample conforms to the expected concentration value and its response value is within the linear range of the calibration curve. If the judgment condition is met, it indicates that the system is stable and the detection of the sample to be tested continues; if the judgment condition is not met, it indicates that the system is unstable or faulty and the calibration curve needs to be measured again or the system needs to be maintained.

[0045] It should be noted that the above steps are not the only and unchangeable ones. After the system completes the initial measurement of the calibration curve, the introduction and measurement steps of the quality control sample can occur before the next measurement of the calibration curve or before the measurement of the sample to be tested, that is, according to the time when the system stability needs to be monitored, the time for introducing the quality control sample is flexibly selected.

[0046] Based on the above technical solution, the introduction time of the quality control sample is before the detection of different batches of samples to be tested, during the detection of the same batch of samples to be tested, or after the detection of different batches of samples to be tested.

[0047] In a preferred embodiment, before starting the batch detection of the sample to be tested, that is, initial verification is carried out using the quality control sample to verify the operation state of the instrument. The analysis result of the quality control sample should conform to the expectation, and its response value should be within the linear range of the previous calibration curve.

[0048] In another preferred embodiment, during the process of detecting and analyzing the same batch of samples, quality control samples are periodically inserted for analysis. The number of injections or the detection time can be used as a cycle to monitor the stability of the system during the analysis process. Any quality control sample that deviates from the expected result may indicate system drift, contamination, instrument failure, or other problems. At this time, the cause needs to be investigated and corresponding measures taken, such as recalibration, system cleaning, or adjustment of instrument parameters, etc.

[0049] In another preferred embodiment, after the batch-by-batch detection and analysis of the samples to be tested are completed, quality control samples are introduced again to determine the end performance of the entire analysis process. At this time, the results of the quality control samples should be similar to those during the initial verification, indicating that the system detection and analysis conditions remain stable throughout the batch and the system stability is good.

[0050] Based on the above technical solution, the on-line preparation method of the standard sample solution includes the following steps:

[0051] Step 1: Rinse with the stock standard solution; rinse the pipeline with the stock standard solution until the pipeline is filled with the stock standard solution and then complete the rinsing.

[0052] Step 2: Rinse with pure water; rinse the inside of the pipeline with pure water until the pipeline is filled with pure water and then complete the rinsing. At this time, except for the pipeline connected to the stock standard solution, other pipelines are filled with pure water, which is the initial state of the pipeline.

[0053] Step 3: Add the stock standard solution; introduce the stock standard solution into the pipeline and add the required amount of the stock standard solution into the dilution container. At this time, there will be a dead volume of the stock standard solution remaining in the pipeline.

[0054] Step 4: Add pure water; introduce pure water into the pipeline and add the required amount of pure water into the same dilution container as in Step 3. The pure water flushes the dead volume of the stock standard solution remaining in Step 3 into the same dilution container. After closing the pure water, except for the pipeline connected to the stock standard solution, other pipelines are filled with pure water. At this time, the required amount of the stock standard solution and pure water are collected in the dilution container, and an on-line dilution process of the stock standard solution is completed to obtain a standard sample solution with a preset concentration. At the same time, the pipeline reaches the initial state in Step 2.

[0055] Step 5: Repeat the above Steps 3 and 4 again to prepare the standard sample solution with the next different concentration, realizing the on-line automatic preparation of the standard sample solutions with different concentrations.

[0056] The online preparation method of the standard sample solution provided in this application realizes the online automatic preparation of the standard sample solution, reduces manual operation, and improves work efficiency and preparation accuracy. The design of each step and its operation sequence effectively solves the influence of the dead volume in the existing instruments and pipelines on the concentration accuracy of the finally prepared solution. It is not affected by the dead volume and has high concentration preparation accuracy. At the same time, it is not necessary to consider the concentration influence between the preparations of two standard sample solutions with different concentrations. During the preparation process, the pipeline is automatically flushed, that is, the initial state of the pipeline is set, and there is no need to repeatedly clean the pipeline additionally, realizing the continuous automatic preparation of standard sample solutions with different required concentrations, with high work efficiency, more convenient use, and strong practicability.

[0057] On the basis of the above technical solution, the quality control sample is prepared by the online preparation method of the standard sample solution.

[0058] In a preferred embodiment, the quality control sample can directly select the prepared solution and enter the detection device for detection in the same way as the sample to be tested to detect the stability of the detection system.

[0059] In another preferred embodiment, the quality control sample is prepared online by the standard sample solution preparation method and enters the detection device for detection through the same channel and method as the standard sample solution.

[0060] This application also provides a cation and anion detection system that can self-check the system stability. The detection system executes the above-mentioned cation and anion detection method that can self-check the system stability. The detection system includes a standard sample online preparation device 1, a sample pretreatment device 2, a sample selection device 3, and an ion chromatography detection device 4. The end of the standard sample online preparation device 1 and the end of the sample pretreatment device 2 are both connected to the head end of the sample selection device 3, and the end of the sample selection device 3 is connected to the ion chromatography detection device 4.

[0061] Among them, the end of the standard sample online preparation device 1 is connected to the sample selection device 3 for the continuous preparation of standard sample solutions with different concentrations; the end of the sample pretreatment device 2 is connected to the sample selection device for the pretreatment of the sample solution to be tested; the end of the sample selection device 3 is connected to the ion chromatography detection device 4 for selecting the standard sample solution, the sample solution to be tested, or the quality control sample, and the ion chromatography detection device 4 is used for quantitative detection of the solution flowing in from the sample selection device 3.

[0062] Based on the above technical solution, the on-line standard sample preparation device 1 includes at least one set of solution dilution assemblies. Each solution dilution assembly includes a standard sample mother liquor bottle 11, a first selection valve 12, a metering pump 13, and a dilution container 14. The head end of the first selection valve 12 is connected to the standard sample mother liquor bottle 11 through a mother liquor pipeline 15 and to the pure water tank 10 through a pure water pipeline 16. The tail end is connected to the head end of the metering pump 13 through a first pipeline 17. The tail end of the metering pump 13 is connected to the dilution container 14 through a second pipeline 18.

[0063] In this application, by setting up the on-line standard sample preparation device, the on-line automatic preparation of the standard sample solution used in the calibration curve can be realized. There is no need to use the method of manual operation or manual cooperation with the preparation instrument in the prior art to prepare, store, and then use the standard sample, reducing manual operation pollution, preparation errors, and measurement deviations caused by the change of the concentration of low-concentration standard samples during long-term storage. Moreover, the on-line preparation device can avoid the adverse effects of the dead volume existing in the existing preparation instrument on the solution concentration accuracy through a new pipeline connection method and preparation process, with more convenient operation and higher preparation efficiency. The concentration preparation accuracy of the standard sample solution is high and the consistency is good, ensuring high detection accuracy in the follow-up. Specifically, the pure water from the pure water tank 10 flows through the pure water pipeline 16, and the standard sample mother liquor from the standard sample mother liquor bottle 15 flows through the mother liquor pipeline 15, respectively passing through the first selection valve 12, the first pipeline 17, the metering pump 13, and the second pipeline 18 and then entering the dilution container 14. A metering pump is provided to accurately measure and transport the preset delivery amounts of pure water and standard sample mother liquor, that is, by adding a preset volume of pure water and standard sample mother liquor and mixing them evenly in the dilution container to dilute and obtain a standard sample solution with a corresponding concentration. The preparation of multiple standard sample solutions with different concentrations can be carried out by respectively transporting the required volumes of pure water and standard sample mother liquor to the dilution container according to the preset concentration. After the on-line preparation of standard sample solutions with different concentrations and then injecting them for detection respectively, the determination of the calibration curve is realized, with simple and convenient operation and high precision.

[0064] In a preferred embodiment, the on-line standard sample preparation device 1 includes a cation solution dilution assembly 101 and an anion solution dilution assembly 102. The cation solution dilution assembly 101 and the anion solution dilution assembly 102 have the same structural assembly and are arranged in parallel, and the tail ends of both are connected to the sample selection device. Setting the preparation and injection of cation and anion solutions as two parallel paths has a relatively high preparation efficiency, will not cause cross-contamination between them, and can also ensure the accuracy of the solution concentration between them.

[0065] More preferably, the pure water in the pure water tank 10 is prepared by a pure water preparation device, realizing the on-line automatic preparation of pure water, providing continuous and reliable pure water for the standard sample on-line preparation device 1 and the ion chromatography detection device 4. It does not require the operation of manually replenishing pure water in the traditional pure water bucket, making the operation more convenient. At the same time, it can also ensure the cleanliness of the pure water and the accuracy of the ion chromatography detection data. Among them, a liquid level sensor is arranged in the pure water tank 10. By setting the liquid level sensor, the pure water in the pure water tank 10 can be prepared and replenished in a timely manner to meet the demand for pure water in the system.

[0066] Specifically, the above-mentioned standard sample on-line preparation device is used for the on-line dilution process of the standard sample stock solution, including the following steps:

[0067] Step 1: Flush the pipeline with the standard sample stock solution. The standard sample stock solution passes through the stock solution pipeline 15, the first selection valve 12, the first pipeline 17, the metering pump 13, and the second pipeline 18 in sequence from the standard sample stock solution bottle 11 to complete the flushing; at this time, the stock solution pipeline 15, the first pipeline 17, and the second pipeline 18 are all filled with the standard sample stock solution;

[0068] Step 2: Flush the pipeline with pure water. The pure water passes through the pure water pipeline 16, the first selection valve 12, the first pipeline 17, the metering pump 13, and the second pipeline 18 in sequence to complete the flushing; at this time, the pure water pipeline 16, the first pipeline 17, and the second pipeline 18 are all filled with pure water; the initial state of the pipeline is set;

[0069] Step 3: The required amount of the standard sample stock solution passes through the stock solution pipeline 15, the first selection valve 12, the first pipeline 17, the metering pump 13, and the second pipeline 18 in sequence and then enters the dilution container 14; at this time, the pure water in the first pipeline 17 and the second pipeline 18 in Step 2 is flushed into the dilution container 14; after closing the standard sample stock solution, there will be a dead volume of the standard sample stock solution remaining in the first pipeline 17 and the second pipeline 18;

[0070] Step 4: The required amount of pure water passes through the pure water pipeline 16, the first selection valve 12, the first pipeline 17, the metering pump 13, and the second pipeline 18 in sequence and then enters the dilution container 14. The pure water flushes the remaining standard sample stock solution in Step 3 into the same dilution container; after closing the pure water, there is still pure water remaining in the first pipeline 17 and the second pipeline 18; at this time, the required amount of the standard sample stock solution and pure water are taken in the dilution container 14, and a dilution process of the standard sample stock solution is completed to obtain a standard sample solution with a preset concentration; at the same time, the pipeline also maintains the initial state in Step 2;

[0071] Step 5: Repeat the above Steps 3 and 4 again to prepare the standard sample solution of the next different concentration, realizing the on-line automatic preparation of the standard sample solutions of different concentrations.

[0072] In a preferred embodiment, the quality control sample can be introduced by online preparation using the above-mentioned standard sample online preparation device 1, and online dilution can be performed according to the required sample concentration to obtain a quality control sample with a specific concentration, which enters the ion chromatography detection device through the sample selection device for detection, and the system stability can be detected based on the detection results.

[0073] As shown in the logic block diagram of the online preparation method of the standard sample solution in the figures, the bold arrows in the figures indicate the liquids added in this step and their flow directions. It should also be noted that the state diagram of the dilution container after adding two liquids is given in the figure, which does not mean that there is a phenomenon such as stratification in the dilution container.

[0074] Specifically, first, during the process of flushing the pipeline: in step one, the pipeline is rinsed with the standard sample mother liquor. The main purpose is that the mother liquor pipeline 15 is filled with the mother liquor concentrate. In step two, the pipeline is rinsed with pure water, that is, except for the mother liquor pipeline 15, the other pipelines, namely the pure water pipeline 16, the first pipeline 17, and the second pipeline 18, are filled with pure water. Secondly, during the continuous preparation process: the first selection valve 12 and the metering pump 13 cooperate to work. First, the required amount of the standard sample mother liquor is added. At this time, the pure water remaining in the pipeline, that is, the pure water in the first pipeline 17 and the second pipeline 18, is added to the dilution container 14, and a part of the dead volume of the standard sample mother liquor will remain in the corresponding pipeline. Then, the required amount of pure water is added. The pure water adds the standard sample mother liquor remaining in the pipeline, that is, the standard sample mother liquor in the first pipeline 17 and the second pipeline 18, to the dilution container 14, and the corresponding pipeline is cleaned into pure water. Since the volume of the pure water remaining in the pipeline at this time is equal to the volume of the pure water remaining in the pipeline in step two, the error caused by the pipeline dead volume of the pure water is eliminated. Similarly, the pipeline dead volume of the standard sample mother liquor is also excluded. At the same time, the pipeline is in the initial state of the pipeline. When the previous concentration of the standard sample solution completes the injection detection, the preparation of the standard sample solution of the next concentration is carried out, that is, the processes of adding the mother liquor and adding pure water in step three and step four above are repeated to complete the preparation of the standard sample solution of the next concentration. Therefore, by using the online continuous preparation method of the standard sample solution in this application, the continuous automatic preparation of standard sample solutions with different concentrations can be realized, and there is no need to repeatedly clean the pipeline, and the operation is more convenient. The setting of each step and the order between steps in the preparation method of this application plays a crucial role and is also one of the important invention points of this application. That is, if the order of flushing or adding liquid of the mother liquor and pure water is changed, not only the error caused by the dead volume cannot be solved, but also a greater preparation error will be brought.

[0075] Based on the above technical solution, the sample pretreatment device 2 includes a sample bottle, a filter 21, and a degassing mechanism 22. The head end of the filter 21 is connected to the sample bottle through a sample pipeline 23, and the tail end is connected to the head end of the degassing mechanism 22. The tail end of the degassing mechanism 22 is connected to the sample selection device 3.

[0076] Before the injection detection in this application, a sample pretreatment device 2 is provided to pretreat the sample to be tested, which can effectively prevent contamination, reduce the influence of possible impurities in the sample on the detection result, and at the same time protect the subsequent ion chromatography detection device 4 and maintain the analysis performance. Specifically, the prepared sample solution to be tested is stored in a sample bottle. When detection is required, the sample to be tested enters the filter through the sample pipeline, removing the possible particulate matter, suspended matter and other impurities in the sample that may interfere with the analysis result or damage the chromatographic system, ensuring the purity of the sample, and thus improving the accuracy and sensitivity of the analysis; the sample solution to be tested flowing out of the filter 21 enters the degassing mechanism 22 to remove the dissolved gas contained in the sample solution to be tested, eliminate the interference of bubbles, maintain a stable flow rate and pressure during transportation, and ensure the accuracy of ion chromatography analysis and the normal operation of the instrument.

[0077] It should be noted that the filter 21 and the degassing mechanism 22 in this embodiment can be obtained from the prior art; among them, the filter is a filtering device such as a common needle-type sample filter, a microporous filter membrane or a pretreatment column, and the degassing mechanism is an on-line degassing mechanism such as common vacuum degassing, membrane degassing or heating degassing.

[0078] In a preferred embodiment, the quality control sample can be introduced into the ion chromatography detection device in the same way as the sample to be tested, that is, the prepared or purchased quality control sample is placed in a sample bottle, pretreated by the above sample pretreatment device, and then enters the ion chromatography detection device through the sample selection device for detection, and the system stability is detected according to the detection result.

[0079] Based on the above technical solution, the sample selection device 3 at least includes an injection selection valve 31. The head end of the injection selection valve 1 is respectively connected to the on-line preparation device 1 of the standard sample and the tail end of the sample pretreatment device 2, and the tail end is connected to the head end of the ion chromatography detection device 4.

[0080] By providing the sample selection device 3, mainly including the injection selection valve 31, each injection selection valve includes at least two channels, that is, one channel can select to enter the standard sample solution for the determination of the calibration curve or select the quality control sample to enter; the other channel selects to enter the sample solution to be tested for the quantitative detection of the actual sample or select the quality control sample to enter, realizing automatic injection selection and making the operation more convenient; more preferably, in this embodiment, two injection selection valves 31 are provided in the sample selection device 3, that is, one corresponds to the injection of the anion standard sample solution and the sample solution to be tested, and the other corresponds to the injection of the cation standard sample solution and the sample solution to be tested, that is, the injection of the anion and cation solutions is separated to avoid cross-contamination, and the detection result is more accurate and the precision is higher.

[0081] Based on the above technical solution, the ion chromatography detection device 4 at least includes a set of ion chromatography detection components. The ion chromatography detection components include a first multi-port valve 41, an eluent generator 42, a chromatographic column 43, a suppressor 44, and a conductivity detector 45. The head end of the first multi-port valve 41 is respectively connected to the sample selection device 3 and the eluent generator 42, and the tail end is connected to the chromatographic column 43. The suppressor 44 and the conductivity detector 45 are sequentially arranged at the tail end of the chromatographic column 43. The eluent generator 42 is connected through a pipeline infusion pump 46, and the inlet of the infusion pump is communicated with the pure water tank 10.

[0082] The prepared standard sample solution, the sample to be measured, or the quality control sample enters the ion chromatography detection device 4 through the sample selection device 3. The eluent is automatically prepared online by the eluent generator 42 to provide continuous supply to the detection system. The sample and the eluent enter the subsequent chromatographic column 43 and suppressor 44 through different channels of the first multi-port valve 41, and finally enter the conductivity detector 45 for detection. The chromatographic column 43 is a key component in ion chromatography analysis. A cation chromatographic column or an anion chromatographic column is set according to the analysis requirements, and the effective separation of each component in the mixture is realized according to the different physical and chemical properties of the substances to be separated. The suppressor 44 is used to remove the strong electrolyte background conductivity in the eluent and improve the detection sensitivity. The conductivity detector 45 is used to measure the conductivity change of the effluent to obtain ion concentration information. Finally, the data processing system receives the electrical signal output by the conductivity detector, forms a calibration curve or a chromatogram, etc., and performs peak identification and quantitative calculation, etc.

[0083] It should be noted that the ion chromatography detection device 4 in this application can use the existing ion chromatograph equipment of the company to complete the quantitative detection of ion concentration. The chromatographic column, suppressor, and conductivity detector therein can be obtained from the prior art as long as ion chromatography detection is achieved.

[0084] In a preferred embodiment, the ion chromatography detection device 4 includes a cation chromatography detection component 401 and an anion chromatography detection component 402, which are correspondingly arranged with the cation solution dilution assembly 101 and the anion solution dilution assembly 102. The structural assemblies of the cation chromatography detection component 401 and the anion chromatography detection component 402 are the same and are arranged in parallel. In this embodiment, the cation chromatography detection component 401 and the anion chromatography detection component 402 are arranged corresponding to the cation solution dilution assembly 101 and the anion solution dilution assembly 102, so as to realize the separate dilution, injection and detection of the cation standard mother liquor and the anion standard mother liquor, which are independent of each other and do not affect each other, avoid cross-contamination between the cation solution and the anion solution, are more convenient to operate, and achieve high-precision detection. Among them, the types of the corresponding eluents, chromatographic columns and suppressors in the cation chromatography detection component 401 and the anion chromatography detection component 402 are all adaptively adjusted according to the detection of cations or anions.

[0085] The selection devices such as the first selection valve, injection selection valve and first multi-way valve mentioned in this application can all adopt multi-channel selection valves in the prior art, which are mainly used for the selection and injection of different liquid samples. The metering pump can be obtained from the prior art, and this application does not involve the improvement of the specific structure of the selection valve or the metering pump. At the same time, the head end and the tail end mentioned above are defined according to the direction of liquid flow, which is only for the convenience of understanding this technical solution and does not constitute a limitation to this application.

[0086] The above has shown and described the basic principles and main features of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments. Therefore, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to include all changes falling within the meaning and scope of the equivalent elements of the claims in the present invention.

[0087] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for detecting anions and cations that can self-check the system stability, characterized in that, It includes the following steps: Online preparation of standard sample solution: According to the preset concentration of the standard sample solution, take the required volumes of pure water and stock standard solution respectively, mix them evenly, and obtain a standard sample solution with a determined concentration after online dilution; Determination of calibration curve: Detect the standard sample solution obtained in the previous step to get the corresponding conductivity detection values; Repeat the preparation and determination of standard sample solutions with different concentrations to complete the numerical detection required for the calibration curve and the drawing of the calibration curve; Pretreatment and detection of samples to be tested: Pretreat the samples to be tested that actually need to be detected to remove the impurities and gases contained in the samples to be tested; Then detect the treated samples to be tested to obtain the corresponding conductivity detection values, form a chromatogram and perform subsequent quantitative calculations; Introduction and determination of quality control samples: Introduce quality control samples with a determined concentration for detection, self-check the system stability according to the judgment conditions, and judge whether to continue the detection of samples to be tested or perform system calibration; Among them, the quality control samples are prepared by the online preparation method of the standard sample solution; The online preparation method of the standard sample solution includes the following steps: Step 1: Rinse with stock standard solution; Rinse the pipeline with the stock standard solution until the pipeline is filled with the stock standard solution and then complete the rinsing; Step 2: Rinse with pure water; Rinse the inside of the pipeline with pure water until the pipeline is filled with pure water and then complete the rinsing; At this time, except for the pipeline connected to the stock standard solution, other pipelines are filled with pure water, which is the initial state of the pipeline; Step 3: Add stock standard solution; Introduce the stock standard solution into the pipeline and add the required amount of stock standard solution into the dilution container. At this time, there will be a dead volume of stock standard solution remaining in the pipeline; Step 4: Add pure water; Introduce pure water into the pipeline and add the required amount of pure water into the same dilution container as in Step 3. The pure water flushes the dead volume of stock standard solution remaining in Step 3 into the same dilution container. After closing the pure water, except for the pipeline connected to the stock standard solution, other pipelines are filled with pure water; At this time, the required amounts of stock standard solution and pure water are collected in the dilution container, and one online dilution process of the stock standard solution is completed to obtain a standard sample solution with a preset concentration; At the same time, the pipeline reaches the initial state in Step 2; Step 5: Repeat the above Steps 3 and 4 again to prepare the standard sample solution with the next different concentration and achieve the online automatic preparation of standard sample solutions with different concentrations.

2. The anion and cation detection method for self-checking system stability according to claim 1, characterized in that The judgment condition is that the measured result of the concentration of the quality control sample meets the expected concentration value and its response value is within the linear range of the calibration curve; If the judgment condition is met, it indicates that the system is stable and continue the detection of samples to be tested. If the judgment condition is not met, it indicates that the system is unstable or faulty and it is necessary to re-determine the calibration curve or perform system maintenance.

3. A method for detecting cations and anions capable of self-checking the stability of a system, as claimed in claim 1, wherein The introduction timing of the quality control samples is before the detection of samples to be tested in different batches or during the detection of samples to be tested in the same batch or after the detection of samples to be tested in different batches.

4. The anion-cation method for self-checking the stability of a system according to claim 1, wherein The online preparation method of the standard sample solution includes the following steps: Step 1: Rinse with stock standard solution; Rinse the pipeline with the stock standard solution until the pipeline is filled with the stock standard solution and then complete the rinsing; Step 2: Flush with pure water; Flush the pipeline with pure water until the pipeline is filled with pure water, and then the flushing is completed. At this time, except for the pipeline connected to the standard sample mother liquor, other pipelines are filled with pure water, which is the initial state of the pipeline. Step 3: Add the standard sample mother liquor; Introduce the standard sample mother liquor into the pipeline and add the required amount of the standard sample mother liquor into the dilution container. At this time, there will be a dead volume of the standard sample mother liquor remaining in the pipeline. Step 4: Add pure water; Introduce pure water into the pipeline and add the required amount of pure water into the same dilution container as in Step 3. The pure water will flush the dead volume of the standard sample mother liquor remaining in Step 3 into the same dilution container. After closing the pure water, except for the pipeline connected to the standard sample mother liquor, other pipelines are filled with pure water. At this time, the required amount of the standard sample mother liquor and pure water are collected in the dilution container, and an online dilution process of the standard sample mother liquor is completed to obtain a standard sample solution with a preset concentration. At the same time, the pipeline reaches the initial state in Step 2. Step 5: Repeat the above Steps 3 and 4 again to prepare the next standard sample solution with a different concentration, so as to achieve the online automatic preparation of standard sample solutions with different concentrations.

5. A method for detecting cations and anions capable of self-checking system stability according to claim 1, characterized in that, The quality control sample is prepared by the online preparation method of the standard sample solution.

6. An anion and cation detection system capable of self-checking system stability, characterized in that, The detection system executes the anion and cation detection method for self-checking the system stability as described in any one of Claims 1 to 5. The detection system includes an online standard sample preparation device (1), a sample pretreatment device (2), a sample selection device (3), and an ion chromatography detection device (4). The end of the online standard sample preparation device (1) and the end of the sample pretreatment device (2) are both connected to the head of the sample selection device (3), and the end of the sample selection device (3) is connected to the ion chromatography detection device (4).

7. The anion and cation detection system according to claim 6, wherein The online standard sample preparation device (1) includes at least one set of solution dilution assemblies. Each solution dilution assembly includes a standard sample mother liquor bottle (11), a first selection valve (12), a metering pump (13), and a dilution container (14). The head of the first selection valve (12) is connected to the standard sample mother liquor bottle (11) through a mother liquor pipeline (15) and to a pure water tank (10) through a pure water pipeline (16), and the end is connected to the head of the metering pump (13) through a first pipeline (17). The end of the metering pump (13) is connected to the dilution container (14) through a second pipeline (18).

8. An anion and cation detection system according to claim 6, characterized in that, The sample pretreatment device (2) includes a sample bottle, a filter (21), and a degassing mechanism (22). The head of the filter (21) is communicated with the sample bottle through a sample pipeline (23), and the end is communicated with the head of the degassing mechanism (22). The end of the degassing mechanism (22) is connected to the sample selection device (3).

9. An anion and cation detection system according to claim 6, characterized in that, The sample selection device (3) includes at least one injection selection valve (31). The head of the injection selection valve (31) is respectively connected to the ends of the online standard sample preparation device (1) and the sample pretreatment device (2), and the end is connected to the head of the ion chromatography detection device (4).

10. A cation and anion detection system according to claim 6, characterized in that, The ion chromatography detection device (4) includes at least one set of ion chromatography detection components. The ion chromatography detection components include a first multi-way valve (41), an eluent generator (42), a chromatographic column (43), a suppressor (44), and a conductivity detector (45). The first end of the first multi-way valve (41) is respectively connected to the sample selection device (3) and the eluent generator (42), and the end is connected to the chromatographic column (43). The suppressor (44) and the conductivity detector (45) are sequentially arranged at the end of the chromatographic column (43). The eluent generator (42) is connected to an infusion pump (46) through a pipeline, and the inlet of the infusion pump is communicated with a pure water tank (10).

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