Electrochemical sensor and method thereof for detecting metal ions

Abstract

The present application relates to the technical field of water quality detection, and provides an electrochemical sensor, and a method thereof for detecting metal ions. The electrochemical sensor provided by the present application comprises: a sensor body; sensing electrodes, disposed on a surface of the sensor body, the sensing electrodes comprising a detection electrode, a reference electrode and a hydrogen ion indicator electrode; and an ion-selective permeable membrane, covering a surface of at least one of the detection electrode and the hydrogen ion indicator electrode. The present application screens corresponding target hydrogen ions or metal ions in a solution by means of the selectively permeable membrane on the sensor body. The pH value of a solution is measured by means of the hydrogen ion indicator electrode, and the concentration of an ion to be measured is calibrated thereby, so as to reduce measurement interference which is easily caused by the acidity or alkalinity of the solution. The concentration of the metal ions is detected by means of the detection electrode, and the concentration of the ion to be measured is calibrated, so as to reduce interference with the ion to be measured caused by interfering ions, thereby improving the accuracy and stability of testing.

Description

Electrochemical Sensors and Methods for Detecting Metal Ions Technical Field

[0001] This application relates to the field of water quality testing technology, and in particular to an electrochemical sensor and a method for detecting metal ions thereon. Background Technology

[0002] Calcium and magnesium ions in water are important indicators in water quality testing. The concentration of these ions directly affects water hardness, which has a significant impact on many industries, including food processing, household life, and agricultural irrigation. Traditional methods for detecting calcium and magnesium ions mainly rely on chemical titration, atomic absorption spectrometry, and inductively coupled plasma mass spectrometry. These methods typically require complex pretreatment steps, expensive equipment, and specialized operators, making them not only costly but also difficult to implement for rapid on-site testing.

[0003] In recent years, electrochemical sensors have become a popular technology choice in fields such as calcium and magnesium ion detection in water and blood gas analysis due to their advantages of high sensitivity, low cost, ease of operation, and portability. However, existing electrochemical sensors suffer from poor stability and reproducibility, and are susceptible to interference from environmental factors. Furthermore, due to the complex composition of water, the output of sensors changes over time under constant concentration conditions, leading to drift and inaccurate results. In particular, divalent metal cations such as calcium and magnesium are more prone to interference than monovalent sodium and potassium ions. Therefore, improving the accuracy, stability, and anti-interference capabilities of electrochemical sensors has become a critical issue that urgently needs to be addressed. Summary of the Invention

[0004] Based on this, this application provides an electrochemical sensor and a method for detecting metal ions, which can improve the accuracy, stability and anti-interference ability of ion detection.

[0005] The electrochemical sensor provided in this application includes:

[0006] Sensor body;

[0007] Sensing electrodes are disposed on the surface of the sensor body, and the sensing electrodes include:

[0008] The detection electrode is used to detect the concentration of metal ions in a solution.

[0009] A reference electrode is used to provide a reference to the detection electrode;

[0010] Hydrogen ion indicating electrode, used to measure the pH value of a solution;

[0011] An ion-selective permeable membrane covers the surface of at least one of the detection electrode and the hydrogen ion indicator electrode.

[0012] Optionally, the detection electrode, reference electrode, and hydrogen ion indicator electrode all include:

[0013] The transmission line section is located on the surface of the sensor body;

[0014] The electrode section is located at one end of the transmission line section and is used to collect data;

[0015] The contact section, located at the other end of the transmission line section, is used to connect measuring equipment.

[0016] Optionally, the ion-selective permeable membrane includes;

[0017] Membrane skeleton;

[0018] Ion carriers, comprising 0.5% to 8% of the ion-selective permeable membrane by mass fraction;

[0019] Surfactants, whose mass fraction in ion-selective permeable membranes ranges from 0 to 4%;

[0020] Plasticizers, which account for 1% to 10% of the mass fraction of the ion-selective permeable membrane.

[0021] Optionally, the ion-selective permeable membrane covering the hydrogen ion indicating electrode further includes:

[0022] The metal chelating agent, comprising 0.1% to 5% by mass of the ion-selective permeable membrane, includes at least one of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, and 1,10-o-phenanthroline.

[0023] Optionally, the electrochemical sensor also includes:

[0024] A gel protective film is applied to the surface of the sensing electrode.

[0025] Optionally, the electrochemical sensor also includes:

[0026] An insulating layer is provided on the surface of the transmission line section to reduce external electrical interference to the transmission line section.

[0027] Optionally, the sensing electrode is a screen-printed electrode.

[0028] Optionally, a reference electrode is used as a potential reference point. The pH value in the solution is measured by a hydrogen ion indicator electrode, and the concentration of the analyte ion in the metal ion is calibrated to reduce the interference of solution acidity or alkalinity on the measurement.

[0029] Optionally, the detection electrode is used to detect the concentration of metal ions. When at least two metal ions are present in the solution, corresponding numbers of detection electrodes are set up respectively. The concentration of the analyte is calibrated by measuring the concentration and potential difference of interfering ions and the analyte in each metal ion measured by the at least two detection electrodes, thereby reducing the interference caused by interfering ions to the analyte.

[0030] Optionally, the sensor is a four-channel electrochemical sensor with a silver chloride reference electrode and a calcium ion electrode and a magnesium ion electrode, both of which are covered with an ion-selective permeable membrane.

[0031] A method for detecting metal ions using the above-mentioned electrochemical sensor includes:

[0032] The electrochemical sensor was placed in a solution, and the potential difference between the detection electrode and the reference electrode, as well as between the hydrogen ion indicator electrode and the reference electrode, was measured to obtain the measurement curves corresponding to the metal ions present in the solution and the measurement curve of hydrogen ions.

[0033] The measurement curves of metal ions and hydrogen ions were compared with the standard curves. The actual measurement signal values ​​obtained by the electrochemical sensor were compared with the values ​​on the standard curve. The corresponding ion concentrations were obtained by proportional substitution and conversion to determine the concentrations of metal ions and hydrogen ions to be detected in the solution.

[0034] The concentration of the calibrated ion in the metal ion is calibrated.

[0035] Optionally, the method for detecting metal ions using the above-mentioned electrochemical sensor further includes:

[0036] The electrochemical sensor is placed in a set of ionic solutions of calibrated concentrations for measurement, and the response of the electrochemical sensor to the concentration gradient of different metal ions is obtained, thus obtaining a standard curve.

[0037] Optionally, calibrating the concentration of the calibrated ion in the metal ions includes:

[0038] Based on the determined concentrations of metal ions in the solution and the influence coefficient of hydrogen ion concentration on the calibrated ion, the concentration value of the calibrated ion is calibrated using the following formula: C 校 =(1-A1×C) H+ )×C 校前

[0039] Among them, C 校 C represents the concentration value of the calibrated ion after calibration. H+ C is the hydrogen ion concentration. H+ The influence coefficient of the calibrated ion electron measurement value, C校前 This is the concentration value of the ion to be calibrated before calibration.

[0040] Optionally, calibrating the concentration of the calibrated ion in the metal ions also includes:

[0041] When two or more metal ions are present in the solution, the calibrated ions among the metal ions are further calibrated.

[0042] During further calibration, the concentration value of the calibrated ion is further calibrated using the following formula, based on the influence coefficient of interfering ions in the metal ion on the measured value of the calibrated ion electrode: C' 校 =(1-A 干扰 )×C 校

[0043] Among them, C' 校 To further calibrate the concentration values ​​of the calibrated ions, A 干扰 This is the influence coefficient of interfering ions on the measured values ​​of the calibrated ion electrode.

[0044] The electrochemical sensor and its method for detecting metal ions provided in this application utilize an ion-selective permeation membrane on the sensor body to screen for target hydrogen ions or metal ions in the solution. These target ions accumulate on the surface of the hydrogen ion indicator electrode or detection electrode in the sensing electrode, forming a potential difference with a reference electrode to determine their concentration. The reference electrode serves as a potential reference point. The pH value of the solution is measured by the hydrogen ion indicator electrode, and the concentration of the analyte is calibrated using this pH value to reduce interference from solution acidity or alkalinity. The concentration of metal ions is detected by the detection electrode. When two or more metal ions are present in the solution, corresponding numbers of detection electrodes are set for each. The concentration and potential difference of interfering ions in each metal ion measured by multiple detection electrodes are used to calibrate the concentration of the analyte, reducing interference from interfering ions and improving the accuracy and stability of the test. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings, without exceeding the scope of protection claimed by this application.

[0046] Figure 1 is a schematic diagram of the structure of the electrochemical sensor provided in this application;

[0047] Figure 2 is a top view of the electrochemical sensor provided in this application;

[0048] Figure 3 is a structural disassembly diagram of the electrochemical sensor provided in this application;

[0049] Figure 4 is a schematic diagram of the process for detecting metal ions using the electrochemical sensor provided in this application;

[0050] Figure 5 is a schematic diagram of the calibration process for the concentration of the calibrated ion in the metal ion.

[0051] Figure 6 is a comparison of the measurement curves before and after calibration when using the electrochemical sensor provided in this application to detect metal ions.

[0052] Explanation of reference numerals in the attached drawings: 1. Sensor body; 2. Sensing electrode; 21. Detection electrode; 22. Reference electrode; 23. Hydrogen ion indicator electrode; 201. Transmission line section; 202. Electrode section; 203. Contact section; 3. Ion-selective permeable membrane; 4. Gel protective membrane; 5. Insulating layer. Detailed Implementation

[0053] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0054] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0055] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0056] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0057] Referring to Figure 1, the electrochemical sensor provided in this application includes a sensor body 1, a sensing electrode 2, and an ion-selective permeable membrane 3; the sensing electrode 2 is disposed on the surface of the sensor body 1. The sensing electrode 2 includes a detection electrode 21, a reference electrode 22, and a hydrogen ion indicator electrode 23. The detection electrode 21 is used to detect the concentration of metal ions in the solution, the reference electrode 22 is used to provide a reference to the detection electrode 21, and the hydrogen ion indicator electrode 23 is used to determine the pH value of the solution. The ion-selective permeable membrane 3 covers the surface of at least one of the detection electrode 21 and the hydrogen ion indicator electrode 23.

[0058] The sensor body 1 is placed in the solution. The ion-selective permeation membrane 3 on the sensor body 1 filters the corresponding target hydrogen ions or metal ions in the solution to achieve a selective potential response to the ions. This causes the ions to accumulate on the surface of the hydrogen ion indicator electrode 23 or detection electrode 21 in the sensing electrode 2, forming a potential difference with the reference electrode 22 to determine the ion concentration. The reference electrode 22 serves as a potential reference point. The pH value of the solution is measured by the hydrogen ion indicator electrode 23, and the concentration of the analyte is calibrated accordingly to reduce interference from the solution's acidity or alkalinity. The concentration of metal ions is detected by the detection electrode 21. When two or more metal ions are present in the solution, corresponding numbers of detection electrodes 21 are set. The concentration and potential difference of interfering ions in each metal ion measured by multiple detection electrodes are used to calibrate the concentration of the analyte, reducing interference and improving the accuracy and stability of the test. The metal ions may include divalent metal cations such as calcium, magnesium, and zinc.

[0059] In some embodiments, the reference electrode 22 may be a silver chloride reference electrode, and the detection electrode 21 may include a divalent cation electrode of metals such as calcium and magnesium.

[0060] Referring to Figure 2, in an optional embodiment, the detection electrode 21, reference electrode 22, and hydrogen ion indicator electrode 23 each include a transmission line section 201, an electrode section 202, and a contact section 203. The transmission line section 201 is disposed on the surface of the sensor body 1. The electrode section 202 is disposed at one end of the transmission line section 201 for data acquisition. The contact section 203 is disposed at the other end of the transmission line section 201 for connecting to a measuring device.

[0061] The electrode section 202 collects test data of each corresponding ion in the solution. The contact section 203 is connected to the measuring device. The data collected by the electrode section 202 is transmitted to the measuring device connected to the contact section 203 through the transmission line section 201 for data processing and analysis.

[0062] Referring to Figure 3, in an optional embodiment, the ion-selective permeable membrane 3 includes a membrane framework, an ion support, a surfactant, and a plasticizer. The ion support comprises 0.5% to 8% of the ion-selective permeable membrane 3 by mass; the surfactant comprises 0% to 4% of the ion-selective permeable membrane 3 by mass; and the plasticizer comprises 1% to 10% of the ion-selective permeable membrane 3 by mass.

[0063] As an optional embodiment, the ion-selective permeable membrane 3 covering the hydrogen ion indicator electrode 23 further includes a metal chelating agent, which accounts for a mass fraction of 0.1% to 5% of the ion-selective permeable membrane 3. The metal chelating agent includes at least one of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, and 1,10-o-phenanthroline.

[0064] Referring to Figure 3, as an optional embodiment, the electrochemical sensor further includes a gel protective film 4, which is disposed on the surface of the sensing electrode 2. The gel protective film 4 protects the surface of the sensing electrode 2.

[0065] Referring to FIG3, as an optional embodiment, the electrochemical sensor further includes an insulating layer 5, which is disposed on the surface of the transmission line section 201 to reduce external electrical interference received by the transmission line section 201.

[0066] As an optional implementation, the sensing electrode 2 is a screen-printed electrode. The screen-printed electrode may include conductive materials such as carbon paste, silver paste, gold paste, or platinum paste.

[0067] It should be noted that the sensing electrode 2 is not limited to screen-printed electrodes. Any electrode form that can react with the ions to be measured and generate an electrical signal, such as carbon rods or gold sheets, can also be used and is suitable for electrochemical ion sensors.

[0068] Referring to Figure 4, this application also provides a method for detecting metal ions using the above-mentioned electrochemical sensor, including steps S120-S140.

[0069] In step S120, the electrochemical sensor is placed in a solution. The electrochemical sensor has a reference electrode 22, a hydrogen ion indicator electrode 23, and detection electrodes 21 corresponding to different metal ions present in the solution. After placement, the potential difference between each detection electrode 21 and the reference electrode 22, and between the hydrogen ion indicator electrode 23 and the reference electrode 22, is measured to obtain the corresponding measurement curves for each metal ion present in the solution and the hydrogen ion measurement curve.

[0070] In step S130, the measurement curves of metal ions and hydrogen ions are compared with their corresponding standard curves. The actual measurement signal values ​​obtained by the electrochemical sensor are compared with the values ​​on the standard curve. The corresponding ion concentrations are obtained by proportional substitution and conversion, so as to determine the concentrations of metal ions and hydrogen ions to be detected in the solution.

[0071] In step S140, the concentration of the calibrated ion in the metal ion is calibrated.

[0072] In summary, by constructing a multi-channel sensing electrode 2, utilizing the cross-interference between each sensing electrode 2 as the basis for data calibration, and performing real-time regression calibration of the measured values ​​through a calibration algorithm, the detection accuracy of divalent cations or metal ions such as calcium, magnesium, and zinc in the solution is effectively improved, enabling component identification in a multi-ion mixed system.

[0073] As an optional implementation, the method for detecting metal ions using the above-described electrochemical sensor further includes step S110.

[0074] In step S110, the electrochemical sensor is placed in a set of ionic solutions of calibrated concentrations for measurement to obtain the response of the electrochemical sensor to different metal ion concentration gradients, thereby obtaining a standard curve.

[0075] Referring to Figure 5, as an optional embodiment, calibrating the concentration of the calibrated ion in the metal ions includes sub-step S141.

[0076] In sub-step S141, based on the determined concentration of metal ions in the solution and the influence coefficient of hydrogen ion concentration on the calibrated ion, the concentration value of the calibrated ion is calibrated using the following formula: C 校 =(1-A1×C) H+ )×C 校前

[0077] Among them, C 校 C represents the concentration value of the calibrated ion after calibration. H+ C is the hydrogen ion concentration. H+ The influence coefficient of the calibrated ion electron measurement value, C 校前 This is the concentration value of the ion to be calibrated before calibration.

[0078] Referring to Figure 5, as an optional embodiment, calibrating the concentration of the calibrated ion in the metal ions further includes sub-step S142.

[0079] In sub-step S142, when two or more metal ions are present in the solution, the calibrated ion among the metal ions is further calibrated. During this further calibration, the concentration of the calibrated ion is further calibrated using the following formula, based on the influence coefficient of interfering ions among the metal ions on the measured value of the calibrated ion electrode: C' 校 =(1-A 干扰 )×C 校

[0080] Among them, C' 校 To further calibrate the concentration values ​​of the calibrated ions, A 干扰 This is the influence coefficient of interfering ions on the measured values ​​of the calibrated ion electrode.

[0081] According to some embodiments, such as that shown in Figure 1, a four-channel electrochemical sensor is described. The reference electrode 22 is a silver chloride reference electrode, and the detection electrode 21 includes a calcium ion electrode and a magnesium ion electrode. The calcium ion electrode and magnesium ion electrode of the detection electrode 21, as well as the hydrogen ion indicator electrode 23, are all covered with an ion-selective permeable membrane 3. The ion-selective permeable membrane 3 covering the calcium ion electrode is a calcium ion selective permeable membrane containing 1.5% by mass of ion carrier. The ion-selective permeable membrane 3 covering the magnesium ion electrode is a magnesium ion selective permeable membrane containing 2% by mass of ion carrier. The hydrogen ion indicator electrode 23 is a pH hydrogen ion electrode, and the ion-selective permeable membrane 3 covering the hydrogen ion indicator electrode 23 is a hydrogen ion selective permeable membrane containing 1% by mass of ion carrier and 0.3% by mass of ethylenediaminetetraacetic acid metal chelating agent.

[0082] This electrochemical sensor was used to measure the concentration of magnesium ions in a solution. During the measurement, the potential difference V between the hydrogen ion indicator electrode 23 and the silver chloride reference electrode was first determined. 41 The hydrogen ion concentration C was determined by comparing the corresponding measurement curve with the standard curve. H+ Under the above-mentioned hydrogen ion selective permeation membrane formulation ratio, the hydrogen ion concentration C H+ Influence coefficient A1 on calcium ion electrode measurement Ca The hydrogen ion concentration C is 0.024. H+ Influence coefficient A1 on the measured value of magnesium ion electrode Mg It is 0.031.

[0083] Measurement of the potential difference between the calcium ion electrode and the silver chloride reference electrode V21 The calcium ion concentration C was determined by comparing it with the standard curve. Ca According to the hydrogen ion concentration C H+ Influence coefficient A1 on calcium ion electrode measurement Ca The calculated calcium ion calibration concentration value is C. H Ca =(1-A1) Ca ×C H+ )×C Ca .

[0084] Among them, C H Ca This is the calibrated calcium ion concentration value, C. Ca This is the calcium ion concentration value before calibration.

[0085] The potential difference V between the magnesium ion electrode and the silver chloride reference electrode again 31 The magnesium ion concentration C was determined by comparing the corresponding measurement curve with the standard curve. Mg According to the hydrogen ion concentration CH+ Influence coefficient A1 on the measured value of magnesium ion electrode Mg The calculated magnesium ion calibration concentration value is C. H Mg =(1-A1) Mg ×C H+ )×C Mg .

[0086] Among them, C H Mg This is the calibrated magnesium ion concentration value, C Mg This is the magnesium ion concentration value before calibration.

[0087] Since the presence of calcium ions in the solution can also interfere with the electrode measurement of magnesium ions, the secondary calibration concentration value of magnesium ions is further calculated based on the calcium ion correction factor A2 to obtain C. H-Ca Mg = (1-A2)*C H Mg .

[0088] Among them, C H-Ca Mg This is the magnesium ion concentration value after secondary calibration.

[0089] Magnesium chloride solutions of 0.25, 0.5, 1, 2, 4, and 8 mM were prepared by adding magnesium chloride to six 10 mL beakers containing aqueous solution. Measurements were taken using a sensor, and the values ​​were calibrated using the above calibration parameters. Simultaneously, the magnesium ion concentration in the six water samples was calibrated using flame atomic absorption spectrometry. Table 1 shows a comparison of the measured values ​​before and after sensor calibration with the calibrated values.

[0090] Table 1

[0091] As shown in Table 1, the deviation rate between the measured and actual magnesium ion values ​​of the six test samples, as determined by flame spectroscopy, ranged from -22% to -14%, while the deviation rate between the calibrated and actual magnesium ion values ​​ranged from -5% to -2%. This demonstrates a significant reduction in the deviation rate.

[0092] According to some embodiments, such as this example, another four-channel electrochemical sensor design is used. In this design, the reference electrode 22 is a silver chloride reference electrode, and the detection electrode 21 includes a calcium ion electrode and a magnesium ion electrode. The calcium ion electrode and magnesium ion electrode of the detection electrode 21, as well as the hydrogen ion indicator electrode 23, are all covered with an ion-selective permeable membrane 3. The calcium ion electrode is covered with a calcium ion-selective permeable membrane containing 1.8% by mass of ion carrier; the magnesium ion electrode is covered with a calcium ion-selective permeable membrane containing 1.8% by mass of ion carrier; and the pH hydrogen ion electrode is covered with a hydrogen ion-selective permeable membrane containing 1% by mass of ion carrier and 0.6% by mass of diethylenetriaminepentaacetic acid metal chelating agent.

[0093] This electrode was used to measure the concentration of magnesium ions in a solution. During the measurement, the potential difference V between the pH hydrogen ion electrode and the silver chloride reference electrode was first determined. 41 The hydrogen ion concentration C was determined by comparing the corresponding measurement curve with the standard curve. H+ In this embodiment, under the hydrogen ion selective permeation membrane formulation ratio, the hydrogen ion concentration C H+ Influence coefficient A1 on calcium ion electrode measurement Ca The hydrogen ion concentration C is 0.043. H+ Influence coefficient A1 on the measured value of magnesium ion electrode Mg The value is 0.067. Similarly, the potential difference between the calcium ion electrode and the magnesium ion electrode and the silver chloride reference electrode is measured, and the concentration value of the calibrated ion is calculated using the formula, and A1 is used. Ca and A1 Mg The magnesium ion calibration concentration value was calculated.

[0094] Magnesium chloride at different concentrations (0.25, 0.5, 1, 2, 4, and 8 mM) was added to six 10 mL beakers containing aqueous solution to prepare magnesium ion solutions. The electrochemical sensor described in this application was used to measure the solutions, and the measured values ​​were calibrated using the aforementioned calibration concentration parameters. Simultaneously, the magnesium ion concentration in the six water samples was calibrated using flame atomic absorption spectrometry. Table 2 shows a comparison of the measured values ​​before and after calibration with the calibrated values ​​of the electrochemical sensor.

[0095] Table 2

[0096] As shown in Table 2, the deviation rate between the measured and actual magnesium ion values ​​of the six test samples, as determined by flame spectroscopy, ranged from 19% to 24%, while the deviation rate between the calibrated and actual magnesium ion values ​​ranged from 2% to 5%. This demonstrates a significant reduction in the deviation rate.

[0097] In some embodiments, the aqueous solution may be mineral water or tap water.

[0098] Figure 6 shows a comparison of the magnesium ion measurement curves before and after calibration. As can be seen from the figure, the use of the electrochemical sensor of this application to detect magnesium ions effectively compensates for the interference caused by hydrogen ions and calcium ions in the measurement.

[0099] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this application. Furthermore, any changes or modifications made by those skilled in the art based on the ideas of this application, and on the specific implementation methods and application scope of this application, are all within the scope of protection of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. An electrochemical sensor, characterized in that, The sensor comprises: a sensor body; a sensing electrode disposed on the surface of the sensor body, the sensing electrode comprising: a detection electrode for detecting the concentration of metal ions in a solution; a reference electrode for providing a reference to the detection electrode; a hydrogen ion indicating electrode for measuring the pH value of the solution; an ion-selective permeable membrane covering the surface of at least one of the detection electrode and the hydrogen ion indicating electrode.

2. The electrochemical sensor of claim 1, wherein, The detection electrode, the reference electrode and the hydrogen ion indicating electrode each comprise: a transmission line portion disposed on the surface of the sensor body; an electrode portion disposed at one end of the transmission line portion for collecting data; a contact portion disposed at the other end of the transmission line portion for connecting to a measuring device.

3. The electrochemical sensor of claim 1, wherein, The ion-selective permeable membrane comprises: a membrane skeleton; an ion carrier, the mass fraction of the ion carrier in the ion-selective permeable membrane ranging from 0.5% to 8%; a surfactant, the mass fraction of the surfactant in the ion-selective permeable membrane ranging from 0 to 4%; a plasticizer, the mass fraction of the plasticizer in the ion-selective permeable membrane ranging from 1% to 10%.

4. The electrochemical sensor according to any one of claims 1 to 3, characterized in that, The ion-selective permeable membrane covering the hydrogen ion indicating electrode further comprises: a metal chelating agent, the mass fraction of the metal chelating agent in the ion-selective permeable membrane ranging from 0.1% to 5%, the metal chelating agent comprising at least one of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid and 1,10-phenanthroline.

5. The electrochemical sensor according to any one of claims 1-3, wherein, The sensor further comprises: a gel protective film disposed on the surface of the sensing electrode.

6. The electrochemical sensor of claim 2, wherein, The sensor further comprises: an insulating layer disposed on the surface of the transmission line portion for reducing external electrical interference on the transmission line portion.

7. The electrochemical sensor according to any one of claims 1-3, wherein, The sensing electrode is a screen-printed electrode.

8. The electrochemical sensor according to any one of claims 1-3, wherein, The reference electrode serves as a potential reference point, measures the pH value of the solution through the hydrogen ion indicating electrode, and calibrates the concentration of the measured ion in the metal ions, reducing the interference of the solution acidity and alkalinity on the measurement.

9. The electrochemical sensor according to any one of claims 1-3, wherein, The detection electrode is used to detect the concentration of the metal ions, and when there are at least two kinds of metal ions in the solution, a corresponding number of detection electrodes are provided, and the concentration of the measured ion is calibrated by the concentration and potential difference of the interfering ion and the measured ion in each of the at least two detection electrodes, reducing the interference of the interfering ion on the measured ion.

10. The electrochemical sensor according to any one of claims 1-3, wherein, The sensor is a four-channel electrochemical sensor, the reference electrode is a silver chloride reference electrode, the detection electrode comprises a calcium ion electrode and a magnesium ion electrode, and the calcium ion electrode and the magnesium ion electrode each have the ion-selective permeable membrane covering thereon.

11. A method for detecting metal ions using the electrochemical sensor according to any one of claims 1 to 10, characterized in that, The method comprises: placing the electrochemical sensor in a solution, and measuring the potential difference between the detection electrode and the reference electrode, and the potential difference between the hydrogen ion indicating electrode and the reference electrode, to obtain a measurement curve corresponding to the metal ions present in the solution and a measurement curve of hydrogen ions; The measurement curve of the metal ion and the measurement curve of the hydrogen ion are compared with a standard curve, each actual measurement signal value measured by the electrochemical sensor corresponds to a value on the standard curve, the corresponding ion concentration is obtained by substituting the value in the standard curve in proportion, so as to determine the metal ion concentration and the hydrogen ion concentration in the solution to be detected; The concentration of the calibrated ion in the metal ion is calibrated.

12. The method of claim 11, wherein, Further comprising: The electrochemical sensor is placed in a group of ion solutions with standard concentrations for measurement, the response of the electrochemical sensor to the concentration gradient of different metal ions is obtained, and thus the standard curve is obtained.

13. The method of claim 11, wherein, The concentration of the calibrated ion in the metal ion is calibrated, comprising: According to the determined concentration of the metal ion in the solution and the influence coefficient of the hydrogen ion concentration on the calibrated ion, the concentration value of the calibrated ion is calibrated by the following calculation formula: C 校＝ (1-A1×C H+ )×C 校前 wherein C 校 is the calibrated concentration value of the calibrated ion, C H+ is the hydrogen ion concentration, A1 is the hydrogen ion concentration C H+ is the influence coefficient of the calibrated ion electronic measurement value on the hydrogen ion concentration, C 校前 is the concentration value of the calibrated ion before calibration.

14. The method of claim 13, wherein, The concentration of the calibrated ion in the metal ion is calibrated, further comprising: When there are two or more metal ions in the solution, the calibrated ion in the metal ion is further calibrated; When the further calibration is performed, the concentration value of the calibrated ion is further calibrated according to the influence coefficient of the interfering ion in the metal ion on the measurement value of the calibrated ion electrode by the following calculation formula: C' 校＝ (1-A 干扰 )×C 校 wherein C 校 is the concentration value of the calibrated ion after further calibration, A 干扰 is the influence coefficient of the interfering ion on the electrode measurement value of the calibrated ion.

Images