Method for improving the accuracy of pH detection of metal antimony-based pH electrode

Abstract

A method for improving the accuracy of pH value detection using an antimony-based pH electrode, belonging to the field of pH value detection technology, includes: measuring the dissolved oxygen concentration of the test solution; comparing this dissolved oxygen concentration with the dissolved oxygen concentration of the standard buffer solution used during pH sensor calibration; when the two dissolved oxygen concentrations differ, dissolved oxygen potential compensation is required: multiplying the difference between the two dissolved oxygen concentrations by a dissolved oxygen concentration compensation coefficient to obtain a dissolved oxygen potential compensation value; and using this dissolved oxygen potential compensation value to compensate the electrode potential of the antimony-based pH electrode in the test solution, thereby achieving accurate pH value measurement. This invention improves the measurement accuracy of the antimony-based pH electrode and the accuracy of in-situ pH value monitoring results through dissolved oxygen potential compensation.

Description

Technical Field

[0001] This invention belongs to the field of pH value detection technology, specifically relating to a method for improving the accuracy of pH value detection using a metal antimony-based pH electrode. Background Technology

[0002] pH is an important parameter for measuring the acidity or alkalinity of substances. Accurate, long-term, and in-situ monitoring of pH is of significant scientific importance in production and daily life. For dilute solutions (ionic strength I < 0.1 mol·kg⁻¹), pH is crucial. -1 The activity of hydrogen ions in a solution is defined as the negative logarithm of the hydrogen ion activity in that solution. ; in, It indicates the activity of hydrogen ions. The molar concentration of hydrogen ions is expressed as Activity coefficient at time Indicates standard molar concentration (1 mol·Kg) -1 The pH value typically ranges from 0 to 14. When pH=7, the solution is neutral; when pH<7, the solution is acidic, and the lower the pH value, the stronger the acidity; when pH>7, the solution is alkaline, and the higher the pH value, the stronger the alkalinity.

[0003] For in-situ monitoring of pH, the existing, conventional, and most commonly used method is the glass electrode-based pH detection method. The glass electrode consists of two independent electrodes: a glass bulb electrode and an external reference electrode with a liquid junction. The hydrogen ion-sensitive structure is a thin glass membrane, whose main chemical component is silicon dioxide, which readily forms a network framework structure. Alkali metal ions such as sodium, potassium, and lithium are stored within this network framework. When the glass electrode is immersed in an aqueous solution, the metal ions present in the network framework exchange with the hydrated ions, thereby generating a membrane potential. This membrane potential is controlled by the hydrogen ion activity, thus producing a pH response. The internal reference electrode is typically a silver / silver chloride electrode, while the external reference electrode is typically a saturated calomel electrode (SCE) or a silver / silver chloride electrode. Although glass electrodes have advantages such as high sensitivity, high measurement accuracy (0.02pH), short response time, and high stability, they still have disadvantages such as low mechanical strength of glass bulbs, easy scratching, and fragile glass membranes, which limit the use of glass electrodes for long-term in-situ monitoring of pH values ​​in complex working environments such as chemical, food processing, and agricultural soil.

[0004] To address the numerous drawbacks of glass electrodes, researchers have developed metal-based pH electrodes using platinum group metal oxides such as iridium (Ir), ruthenium (Ru), and palladium (Pd) and semiconductor metals / metal oxides such as tungsten (W), antimony (Sb), titanium (Ti), tantalum (Ta), and tin (Sn) as pH-responsive materials. Compared to glass electrodes, metal-based pH electrodes offer advantages such as high mechanical strength, resistance to high temperatures and pressures, low internal resistance, ease of miniaturization, and long service life, making them a potential alternative to glass electrodes for long-term in-situ monitoring under complex conditions. However, metal-based pH electrodes still suffer from the following drawbacks in practical use: relatively poor testing stability, susceptibility to hysteresis effects, and susceptibility to interference from oxidants and reducing agents, resulting in lower measurement accuracy compared to glass electrodes, and discrepancies between measurement results obtained with glass electrodes in the same solution. Summary of the Invention

[0005] To address the problem of poor measurement accuracy of existing antimony-based pH electrodes in laboratory pH testing and / or in-situ monitoring, this invention provides a method for improving the accuracy of pH detection using antimony-based pH electrodes.

[0006] This invention aims to solve the problem of low accuracy in pH value detection results of antimony-based pH electrodes. In the field of long-term in-situ pH value monitoring, it can provide a more accurate testing method for solid antimony-based pH electrodes to replace fragile glass electrodes.

[0007] The technical solution adopted by this invention to solve the technical problem is as follows: This invention provides a method for improving the accuracy of pH value detection using an antimony-based pH electrode, comprising the following steps: The dissolved oxygen concentration of the test solution is measured and compared with the dissolved oxygen concentration of the standard buffer solution used during pH sensor calibration. When the two dissolved oxygen concentrations are different, dissolved oxygen potential compensation is required: the difference between the two dissolved oxygen concentrations is multiplied by the dissolved oxygen concentration compensation coefficient to obtain the dissolved oxygen potential compensation value. This value is then used to compensate the electrode potential of the antimony-based pH electrode in the test solution, thereby achieving accurate pH measurement.

[0008] As a preferred embodiment, the following steps are included: Step S1: Calibrate the pH sensor in a standard buffer solution to obtain the standard equation for the linear relationship between electrode potential and pH value; Step S2: Determine the dissolved oxygen concentration in the standard buffer solution; Step S3: Change the dissolved oxygen concentration in the standard buffer solution, and calculate the dissolved oxygen concentration compensation coefficient based on the linear relationship between the electrode potential of the antimony-based pH electrode and the dissolved oxygen concentration in the standard buffer solution. Step S4: Determine the dissolved oxygen concentration of the solution to be tested; Step S5: Compare the dissolved oxygen concentration of the test solution with the dissolved oxygen concentration of the standard buffer solution measured in step S2. When the two dissolved oxygen concentrations are different, multiply the difference between the two dissolved oxygen concentrations by the dissolved oxygen concentration compensation coefficient to obtain the dissolved oxygen potential compensation value. Use this dissolved oxygen potential compensation value to compensate the electrode potential of the antimony-based pH electrode in the test solution.

[0009] In a preferred embodiment, in step S3, the dissolved oxygen concentration in the standard buffer solution is changed by introducing oxygen of different concentrations into the standard buffer solution.

[0010] In a preferred embodiment, in step S3, the average value of the linear coefficients corresponding to the linear relationship between the electrode potential and dissolved oxygen concentration in the standard buffer solution is the dissolved oxygen concentration compensation coefficient.

[0011] In a preferred embodiment, in step S5, the mathematical expression for compensating the electrode potential of the antimony-based pH electrode using the dissolved oxygen potential compensation value is: E = E1 + E2; where E is the electrode potential of the antimony-based pH electrode after dissolved oxygen potential compensation, E1 is the measured electrode potential of the antimony-based pH electrode in the test solution, and E2 is the dissolved oxygen potential compensation value.

[0012] In a preferred embodiment, the antimony-based pH electrode is a pure antimony electrode, a silver-antimony alloy electrode, a copper-antimony alloy electrode, or an antimony / antimony trioxide electrode.

[0013] In a preferred embodiment, a pH sensor is constructed using a metal antimony-based pH electrode as the pH test electrode and an Ag / AgCl electrode as the reference electrode to test the pH value of the solution. The accuracy of the pH sensor test is improved by using a dissolved oxygen potential compensation method.

[0014] The beneficial effects of this invention are: This invention provides a method to improve the accuracy of pH detection using a metal antimony-based pH electrode. It solves the problem of inconsistency between the measurement results of the metal antimony-based pH electrode and the glass electrode in the same solution, as well as the problem of poor measurement accuracy of existing metal antimony-based pH electrodes in in-situ pH monitoring. This invention uses the measurement results of the glass electrode as a benchmark and improves the measurement accuracy of the metal antimony-based pH electrode and the accuracy of in-situ pH monitoring results through dissolved oxygen potential compensation, especially for metal antimony-based pH electrodes. Attached Figure Description

[0015] Figure 1The calibration curves are obtained by measuring the electrode potential of the antimony-based pH electrode in standard buffer solutions at pH 4.00, pH 6.86, and pH 9.18.

[0016] Figure 2 The electrode potential (E) of the antimony-based pH electrode in standard buffer solutions at pH 4.00, pH 6.86, and pH 9.18. 锑 The variation of dissolved oxygen (DO) concentration.

[0017] Figure 3 The electrode potential (E) of the antimony-based pH electrode in standard buffer solutions at pH 4.00, pH 6.86, and pH 9.18. 锑 The linear relationship between dissolved oxygen concentration (DO) and dissolved oxygen concentration (DO).

[0018] Figure 4 This is a schematic diagram of the dissolved oxygen potential compensation principle. Detailed Implementation

[0019] This invention provides a method for improving the accuracy of pH detection using a metal antimony-based pH electrode, based on the pH response mechanism of the metal-based pH electrode. The specific analysis of the pH response mechanism of the metal-based pH electrode and the metal antimony-based pH electrode is as follows: (1) pH response mechanism of metal-based pH electrodes; The pH response mechanism of metal-based pH electrodes is usually based on redox reactions, and the equilibrium redox reaction is represented as: (1); in, This is the general formula for metal oxides. For a metal, the range of x is x≥1 and the range of y is y≥1; This represents the number of electrons transferred during the reaction. According to the Nernst equation, the electrode potential of a metal-based pH electrode is expressed as: (2); Where E is the electrode potential of the metal-based pH electrode, in volts (V). for Standard electrode potential is the electrode potential under standard conditions (activity of all substances is 1, partial pressure of gas is 100 kPa, and temperature is 298.15 K); R is the gas constant, which is equal to 8.314 J·mol⁻¹. -1 K -1 T is the thermodynamic temperature, T (K) = t (°C) + 273.15; F is the Faraday constant, which is 96485°C / mol. Hydrogen ion activity; for The activity of , for solid metal oxides, is usually 1 under standard conditions; Hydrogen ion activity; Metal The activity of is typically 1 under standard conditions; It represents the activity of water, which is typically 1 under standard conditions.

[0020] Therefore, when the number of electrons transferred in the reaction is equal to the coefficient of the hydrogen ions participating in the reaction, equation (2) can be simplified to the following form: (3); By defining dilute solutions (ionic strength I < 0.1 mol·Kg) -1 (of the solution) Substituting this into equation (3), we get: (4); in, for Standard electrode potential, in V; 0.05916 is in V / pH, which is the theoretical response sensitivity of the pH electrode at 25℃, also known as the Nernst slope.

[0021] According to equation (4), under ideal conditions, the electrode potential of a metal-based pH electrode is only affected by temperature and hydrogen ion activity. The effect of temperature can be reduced or even eliminated through temperature compensation. Therefore, the electrode potential of a metal-based pH electrode is only related to pH. Thus, the purpose of testing pH value can be achieved by measuring the electrode potential of a metal-based pH electrode. However, equation (1) reflects the redox reaction in equilibrium and cannot reflect the factors affecting the equilibrium during the redox reaction. The factors affecting the equilibrium during the redox reaction often ultimately affect the accuracy of the test results.

[0022] (2) pH response mechanism of antimony-based pH electrode; The pH response mechanism of an antimony-based pH electrode can be simply represented as follows: ; At a temperature of 298.15 K, the electrode potential of the antimony-based pH electrode can be expressed as: ; in, for Standard electrode potential is the electrode potential under standard conditions (activity of all substances is 1, partial pressure of gas is 100 kPa, and temperature is 298.15 K); R is the gas constant, which is equal to 8.314 J·mol⁻¹. -1 K -1T is the thermodynamic temperature, T (K) = t (°C) + 273.15; F is the Faraday constant, which is 96485°C / mol.

[0023] Equation (6) only reflects the relationship between the electrode potential E and pH value of the antimony-based pH electrode in equilibrium, but it cannot reflect the root cause of the electrode potential of the antimony-based pH electrode or the factors affecting the electrode potential of the antimony-based pH electrode during the pH response process. Existing studies have shown that the electrode potential of the antimony-based pH electrode originates from the corrosion potential, and the magnitude of the corrosion potential is affected by the dissolved oxygen concentration in the solution.

[0024] Specifically, antimony-based pH electrodes undergo corrosion in aerobic aqueous solutions, and the overall corrosion reaction involved in this process is as follows: 4Sb + 3O2+ 2H2O = 4HSbO2(7); Equation (7) can be decomposed into an antimony oxidation reaction occurring at the anode and an oxygen reduction reaction occurring at the cathode; The antimony oxidation reaction that occurs at the anode is as follows: Sb + 2H₂O = HSbO₂ + 3H₂O + + 3e - (8); The oxygen reduction reaction that occurs at the cathode is as follows: O2+ 4H + + 4e - = 2H2O(9; At 298.15 K, the equilibrium electrode potential of the antimony-based pH electrode is as follows: The reducing half-reaction: HSbO2 + 3H+ + + 3e - = Sb + 2H₂O, where the number of electrons transferred n=3, assuming (Sb metal exists in solid phase; H2O dilute aqueous solution exists in liquid phase; HSbO2 exists on the surface of antimony electrode as a continuous, dense pure solid film). hour: ; According to the Nernst equation, the electromotive force of the oxygen reduction electrode is: ; Corrosion driving force, corrosion electromotive force: ; As can be seen from equation (10), the equilibrium electrode potential of the antimony-based pH electrode depends on the pH value of the solution. As can be seen from equation (12), the driving force of this corrosion system does not change with the pH of the aqueous solution. The oxygen reduction potential is always higher than the potential of the antimony-based pH electrode. Thermodynamically, the antimony-based pH electrode has a spontaneous corrosion tendency in oxygen-containing aqueous solutions.

[0025] Antimony-based pH electrodes undergo oxygen absorption corrosion in oxygen-containing aqueous solutions, with the system exhibiting a pair of conjugate electrode reactions: antimony oxidation and dissolved oxygen reduction. The equilibrium electrode potentials of Sb / HSbO2 and O2 / H2O are determined by the Nernst equation, and the potential difference between them is the thermodynamic driving force of the corrosion reaction. The system's open-circuit potential is a mixed potential formed by the coupling of conjugate reactions, its value lying between the anodic and cathodic equilibrium potentials. It can directly characterize the actual corrosion state of the electrode and is influenced by both the solution pH and the dissolved oxygen partial pressure. In the actual testing of the antimony-based pH electrode sensor, this invention measures the system's open-circuit potential; therefore, the measured open-circuit potential of the antimony-based pH electrode sensor is influenced by both the solution pH and dissolved oxygen activity.

[0026] The electrode potential derivation of this invention is based on a steady-state corrosion scenario at 298.15 K, in a neutral / weakly alkaline environment, where a stable HSbO2 passivation film forms on the surface of an antimony electrode. Under this scenario, the activity of pure metallic antimony... The solid-phase antimonylic acid HSbO2 is a continuous and dense pure solid passivation film with an activity of Therefore, the electrode potential is only affected by the solution pH and dissolved oxygen activity.

[0027] The applicable boundaries of this assumption are: room temperature, neutral / weakly alkaline, steady-state passivation system. For scenarios such as strong acid, strong alkalinity, high flow rate, and the initial stage of dynamic corrosion, HSbO2 exists as a dissolved or metastable intermediate product, and its activity is no longer constant at 1. The electrode potential needs to introduce the HSbO2 activity variable, the value of which is jointly determined by factors such as anodic dissolution kinetics, mass transfer conditions, and phase transformation rate.

[0028] In this invention, the equilibrium electrode potential is calculated separately using the Nernst equation, while the measured open-circuit potential is a mixed potential formed by conjugate reaction coupling, and the two are clearly distinguishable. The simplified model of this invention is a first-order approximation under steady-state scenarios, and has a clear scope of application and predictive reliability.

[0029] Based on the above analytical results, this invention proposes a method to improve the accuracy of pH detection using a metal antimony-based pH electrode. Specifically, it improves the accuracy of pH detection by using dissolved oxygen potential compensation. Dissolved oxygen (DO) is molecular oxygen dissolved in water, usually denoted as DO and expressed as milligrams of oxygen per liter of water. The amount of dissolved oxygen in water is an indicator of a water body's self-purification capacity.

[0030] Specifically, this invention provides a method for improving the accuracy of pH value detection using a metal antimony-based pH electrode. When using a metal antimony-based pH electrode for in-situ pH value monitoring in laboratory or industrial fields, the dissolved oxygen concentration of the test solution is first measured simultaneously. Then, this dissolved oxygen concentration is compared with the dissolved oxygen concentration of the standard buffer solution used during pH sensor calibration. When the two dissolved oxygen concentrations are different, dissolved oxygen potential compensation is required: the difference between the two dissolved oxygen concentrations is multiplied by a dissolved oxygen concentration compensation coefficient to obtain a dissolved oxygen potential compensation value. This value is then used to compensate for the electrode potential of the metal antimony-based pH electrode in the test solution, ultimately achieving accurate pH value measurement.

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1: A method for improving the accuracy of pH detection using a solid antimony-based metal pH electrode. Antimony-based pH electrodes (including pure antimony electrodes, M-antimony alloy electrodes, antimony / antimony trioxide electrodes, etc.) A pH sensor is constructed using a metal (including silver, copper, etc.) as the pH testing electrode and an Ag / AgCl (saturated KCl) electrode as the reference electrode to measure the pH value of a solution. This invention provides a method for improving the accuracy of pH detection using a metal antimony-based pH electrode, namely, a dissolved oxygen potential compensation method. The specific implementation process is as follows: (1) A pH sensor was constructed using a metal antimony-based pH electrode as the response electrode and an Ag / AgCl (saturated KCl) electrode as the reference electrode. The constructed pH sensor was calibrated in standard buffer solutions at pH 4.00, pH 6.86, and pH 9.18 under ambient temperature (25℃) and atmospheric pressure (1 atm) conditions, and the calibration curves are shown below. Figure 1As shown, the standard equation (calibration equation) for the linear relationship between the electrode potential and pH value of the antimony-based pH electrode is: E 锑 =-49.5 pH+3.03 (R) 2 =0.999).

[0033] (2) The dissolved oxygen concentrations in standard buffer solutions with pH 4.00, pH 6.86, and pH 9.18 under room temperature (25℃) and normal pressure (1 atm) conditions were measured using a dissolved oxygen sensor (Shanghai Leici JPB-607A portable dissolved oxygen meter) and recorded in Table 1. The test results shown in Table 1 indicate that the dissolved oxygen concentrations in the three standard buffer solutions are similar under normal temperature and pressure conditions.

[0034] Table 1. Dissolved oxygen concentration in standard buffer solutions under ambient temperature (25℃) and normal pressure (1 atm) conditions.

[0035] (3) Different concentrations of oxygen were introduced into standard buffer solutions with pH 4.00, pH 6.86, and pH 9.18, respectively. The oxygen was obtained through an oxygen generator. The dissolved oxygen concentration in the standard buffer solutions was changed, and the dissolved oxygen concentration was measured using a dissolved oxygen sensor (Shanghai Leici JPB-607A portable dissolved oxygen meter). At the same time, the electrode potential of the antimony-based pH electrode at each dissolved oxygen concentration in the standard buffer solutions was recorded using a potentiometer or electrochemical workstation. The electrode potential (E) of the antimony-based pH electrode was recorded. 锑 Changes with dissolved oxygen (DO) concentration Figure 2 As shown, in standard buffer solutions with pH 4.00, pH 6.86, and pH 9.18, the electrode potential (E) of the antimony-based pH electrode increases with increasing dissolved oxygen concentration. 锑 All are positive shifts.

[0036] (4) According to Figure 2 Plot the electrode potentials (E0) of antimony-based pH electrodes in standard buffer solutions at pH 4.00, pH 6.86, and pH 9.18. 锑 The linear relationship between dissolved oxygen (DO) and dissolved oxygen concentration is shown in the figure. Figure 3 As shown, the electrode potentials (E0) of the antimony-based pH electrode in standard buffer solutions at pH 4.00, pH 6.86, and pH 9.18 are... 锑 The linear relationships between E and dissolved oxygen concentration (DO) are as follows: 锑 =4.56 DO-200.9 (R) 2 =0.960), E 锑 =4.95 DO-355.11 (R) 2=0.984) and E 锑 =5.86 DO-462.5 (R) 2 =0.989), with corresponding linear coefficients of 4.56 mV / (mg / L), 4.95 mV / (mg / L), and 5.86 mV / (mg / L), respectively. The average linear coefficients from the three standard buffer solutions yielded a dissolved oxygen concentration compensation coefficient of k = 5.13 mV / (mg / L) for the antimony-based pH electrode.

[0037] (5) A pH sensor consisting of a metal antimony-based pH electrode as the response electrode and an Ag / AgCl (saturated KCl) electrode as the reference electrode was used to test the pH value of the solution, and the pH sensor test accuracy was improved by using dissolved oxygen potential compensation.

[0038] like Figure 4 As shown, this pH sensor measures the electrode potential E of the antimony-based pH electrode in the test solution. 锑测试 Without dissolved oxygen potential compensation, the pH value of the test solution is calculated as pH0 according to the calibration equation. However, the dissolved oxygen concentration measured by the dissolved oxygen sensor may be DO1 or DO2, while the dissolved oxygen concentration corresponding to the calibration equation is DO0 (DO0 = 3.64 mg / L). In this case, dissolved oxygen potential compensation is needed to improve the accuracy of the test. The specific operation method is as follows: calculate the dissolved oxygen potential compensation values ​​E corresponding to the dissolved oxygen concentrations DO1 and DO2. 锑补偿1 =k (DO0-DO1) and E 锑补偿2 =k (DO0 - DO2), where DO2 > DO0 > DO1, the electrode potentials of the antimony-based pH electrode after dissolved oxygen potential compensation are E 锑1 =E 锑测试 +E 锑补偿1 and E 锑2 =E 锑测试 +E 锑补偿2 The pH values ​​of the test solution were then calculated using the calibration equation to obtain pH1 and pH2, respectively. The difference between pH0 and pH1, and the difference between pH0 and pH2, represent the errors caused by not compensating for dissolved oxygen potential.

[0039] (6) Verification of dissolved oxygen potential compensation effect using actual samples; An outdoor natural water body was sampled, and the pH value was measured to be 9.60 using a calibrated glass electrode. A metal antimony-based pH electrode was used to measure the potential at -456 mV, and a dissolved oxygen sensor was used to measure DO2 at 6.46 mg / L. Without dissolved oxygen potential compensation, the pH value of the natural water body measured by the metal antimony-based pH electrode was (-456 - 3.03) / -49.5 = 9.27, which differs from the glass electrode result of 9.60 by ΔpH = pH. 玻璃 -pH 锑 =9.60-9.27=0.33. The electrode potential ΔE of the antimony-based pH electrode after dissolved oxygen potential compensation is... 锑 =k (DO0-DO2)=5.13 (3.64-6.46) = -14.5 mV, the electrode potential E of the antimony-based pH electrode after dissolved oxygen potential compensation. 锑 =E 锑测试 +E 锑补偿 =-456-14.5= -470.5mV. After dissolved oxygen potential compensation, the pH measured by the antimony-based pH electrode is (-470.5-3.03) / -49.5=9.57. The difference between the compensated antimony-based pH electrode result of 9.57 and the glass electrode result of 9.60 is ΔpH=pH. 玻璃 -pH 锑 =9.60-9.57=0.03. Compared with the glass electrode, the test results after compensation are significantly improved compared with the test results without compensation. The accuracy of pH value testing by the antimony-based metal pH electrode is greatly improved, indicating that the present invention has achieved significant beneficial effects.

[0040] This invention discloses a method for improving the accuracy of pH value detection using an antimony-based pH electrode. Those skilled in the art can refer to this document and appropriately modify the process parameters to achieve the desired result. It is particularly important to note that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The product of this invention has been described through preferred embodiments, and those skilled in the art will clearly be able to modify or appropriately change and combine the product described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

Claims

1. A method for improving the accuracy of pH detection by a metal antimony-based pH electrode, characterized in that, Includes the following steps: The dissolved oxygen concentration of the test solution is measured and compared with the dissolved oxygen concentration of the standard buffer solution used during pH sensor calibration. When the two dissolved oxygen concentrations are different, dissolved oxygen potential compensation is required: the difference between the two dissolved oxygen concentrations is multiplied by the dissolved oxygen concentration compensation coefficient to obtain the dissolved oxygen potential compensation value. This dissolved oxygen potential compensation value is used to compensate the electrode potential of the antimony-based pH electrode in the test solution to achieve accurate pH value measurement. The method includes the following steps: Step S1: Calibrate the pH sensor in a standard buffer solution to obtain the standard equation for the linear relationship between electrode potential and pH value; Step S2: Determine the dissolved oxygen concentration in the standard buffer solution; Step S3: Change the dissolved oxygen concentration in the standard buffer solution, and calculate the dissolved oxygen concentration compensation coefficient based on the linear relationship between the electrode potential of the antimony-based pH electrode and the dissolved oxygen concentration in the standard buffer solution.

2. The method for improving the accuracy of pH detection of a metal antimony-based pH electrode according to claim 1, characterized in that, The method also includes the following steps: Step S4: Determine the dissolved oxygen concentration of the solution to be tested; Step S5: Compare the dissolved oxygen concentration of the test solution with the dissolved oxygen concentration of the standard buffer solution measured in step S2. When the two dissolved oxygen concentrations are different, multiply the difference between the two dissolved oxygen concentrations by the dissolved oxygen concentration compensation coefficient to obtain the dissolved oxygen potential compensation value. Use this dissolved oxygen potential compensation value to compensate the electrode potential of the antimony-based pH electrode in the test solution.

3. The method for improving the accuracy of pH detection of a metal antimony-based pH electrode according to claim 2, characterized in that, In step S3, the dissolved oxygen concentration in the standard buffer solution is changed by introducing different concentrations of oxygen into the standard buffer solution.

4. The method for improving the accuracy of pH detection of a metal antimony-based pH electrode according to claim 2, characterized in that, In step S3, the average value of the linear coefficients corresponding to the linear relationship between the electrode potential and dissolved oxygen concentration in the standard buffer solution is the dissolved oxygen concentration compensation coefficient.

5. The method for improving the accuracy of pH detection of a metal antimony-based pH electrode according to claim 2, characterized in that, In step S5, the mathematical expression for compensating the electrode potential of the antimony-based pH electrode using the dissolved oxygen potential compensation value is: E = E1 + E2; where E is the electrode potential of the antimony-based pH electrode after dissolved oxygen potential compensation, E1 is the measured electrode potential of the antimony-based pH electrode in the test solution, and E2 is the dissolved oxygen potential compensation value.

6. The method for improving the accuracy of pH detection of a metal antimony-based pH electrode according to claim 1, characterized in that, The antimony-based pH electrode is a pure antimony electrode, a silver-antimony alloy electrode, a copper-antimony alloy electrode, or an antimony-antimony trioxide electrode.

7. The method for improving the accuracy of pH detection of a metal antimony-based pH electrode according to claim 1, characterized in that, A pH sensor was constructed using an antimony-based pH electrode as the pH test electrode and an Ag / AgCl electrode as the reference electrode to test the pH value of a solution. The accuracy of the pH sensor was improved by employing dissolved oxygen potential compensation.

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