Calibration method and calibration system for hydrogen superoxide radical detector

Abstract

The present disclosure provides a calibration method and system for a hydrogen superoxide radical detector, wherein the calibration method comprises: converting a first hydrogen superoxide radical sample into gaseous nitrous acid to obtain the concentration of the gaseous nitrous acid; obtaining the standard concentration of the hydrogen superoxide radical based on the conversion relationship between the first hydrogen superoxide radical sample and the gaseous nitrous acid; detecting a second hydrogen superoxide radical sample by using the hydrogen superoxide radical detector to obtain the detection concentration of the hydrogen superoxide radical; and calibrating the hydrogen superoxide radical detector according to the standard concentration and the detection concentration to obtain the calibrated hydrogen superoxide radical detector; wherein the first hydrogen superoxide radical sample and the second hydrogen superoxide radical sample have the same concentration.

Description

Technical Field

[0001] This disclosure relates to the field of chemical analysis technology, and specifically to a calibration method and calibration system for a hydrogen superoxide radical detector. Background Technology

[0002] Hydrogen superoxide (HO2) radicals are crucial oxidants in the atmosphere, rapidly oxidizing nitric oxide (NO) to nitrogen dioxide (NO2). The photolysis of NO2 is the only pathway for tropospheric ozone formation. The bimolecular self-reaction of HO2 radicals generates hydrogen peroxide, and the reaction of HO2 radicals with organic peroxide radicals produces organic peroxides, which are key components in acid rain formation. Furthermore, the majority of HO2 radicals in the atmosphere originate from the oxidation of carbon monoxide (CO) and volatile organic compounds (VOCs) by hydroxyl (OH) radicals. These hydroxyl radicals can then react with NO to regenerate OH radicals, forming a cycle between OH and HO2 radicals. This cycle plays a central role in tropospheric atmospheric chemistry, directly impacting the degradation of primary pollutants and the formation of secondary pollutants. Therefore, understanding the concentration level of HO2 radicals in the atmosphere has always been a focus of research in atmospheric environmental chemistry.

[0003] Currently, the detection of HO2 free radicals in the atmosphere requires calibration methods to determine the concentration of free radicals. The most commonly used method is water photolysis, but the O2 and NO2 chemiphotometers used in this method complicate the experimental procedures, and the accompanying side reactions may increase the uncertainty of the calibration results. Furthermore, some of the free radicals generated by the photolysis of water molecules are lost on the tube wall, which may lead to deviations in the calibration results of HO2 free radical concentration in the atmosphere. Therefore, there is an urgent need to develop a simple and reliable method and device for calibrating atmospheric HO2 free radicals. Summary of the Invention

[0004] In view of this, the present disclosure provides a calibration method and calibration system for a hydrogen superoxide radical detector, so as to at least partially solve the above-mentioned technical problems.

[0005] To solve the above-mentioned technical problems, the technical solution provided in this disclosure is as follows:

[0006] As one aspect of this disclosure, a calibration method for a hydrogen superoxide radical detector is provided, comprising:

[0007] The first superoxide radical sample was converted into gaseous nitrous acid, and the concentration of gaseous nitrous acid was obtained.

[0008] Based on the conversion relationship between the first superoxide radical sample and gaseous nitrous acid, the standard concentration of superoxide radicals was obtained;

[0009] The second superoxide radical sample was detected using a superoxide radical detector to obtain the concentration of superoxide radicals.

[0010] The hydrogen superoxide radical detector was calibrated based on the standard concentration and the detection concentration to obtain the calibrated hydrogen superoxide radical detector.

[0011] The first and second superoxide radical samples had the same concentration.

[0012] According to embodiments of this disclosure, calibrating the superoxide radical detector based on a standard concentration and a detection concentration includes:

[0013] Linearity analysis was performed between the standard concentration and the detected concentration to obtain the correction coefficient;

[0014] The response value of the hydrogen superoxide radical detector is corrected according to the correction coefficient.

[0015] According to embodiments of this disclosure, the calibration method for the hydrogen superoxide radical detector further includes:

[0016] A free radical sample containing hydroxyl radicals and first superoxide radicals was generated using a free radical generator.

[0017] The hydroxyl radicals in the free radical sample were converted into second superoxide radicals.

[0018] The first superoxide radical sample or the second superoxide radical sample is composed of the first superoxide radical and the second superoxide radical.

[0019] According to embodiments of this disclosure, generating a free radical sample containing hydroxyl radicals and a first superoxide radical using a free radical generator includes:

[0020] A constant flow rate of water molecules is introduced into a free radical generator. The water molecules are irradiated with 184.9 nm ultraviolet light generated by a low-pressure mercury lamp, causing the water molecules to photolyze and generate hydroxyl radicals and hydrogen atoms. The hydrogen atoms react with oxygen to generate the first superoxide radical. The free radical sample is composed of hydroxyl radicals and superoxide radicals.

[0021] The conversion of hydroxyl radicals in a free radical sample into second superoxide radicals includes:

[0022] The hydroxyl radical is converted into a second superoxide radical by reacting carbon monoxide with the hydroxyl radical.

[0023] According to embodiments of this disclosure, converting a first hydrogen superoxide radical sample into gaseous nitrous acid includes:

[0024] The first superoxide radical sample was converted into gaseous nitrous acid by reacting excess nitric oxide with the first superoxide radical sample.

[0025] As another aspect of this disclosure, a calibration system for a hydrogen superoxide radical detector based on the above-described calibration method is disclosed, the calibration system comprising:

[0026] A chemical conversion device for converting a first superoxide radical sample into gaseous nitrous acid;

[0027] A gaseous nitrous acid (HONO) detector is used to detect the concentration of gaseous nitrous acid and obtain its concentration.

[0028] A hydrogen superoxide (HO2) radical detector is used to detect second-order hydrogen superoxide radical samples and obtain the detection concentration of hydrogen superoxide radicals; and

[0029] The calibration analysis unit is used to calibrate the hydrogen superoxide radical detector based on the standard concentration and the detection concentration.

[0030] The first and second superoxide radical samples had the same concentration.

[0031] According to embodiments of this disclosure, the correction system further includes:

[0032] A free radical generator is used to photolyze water molecules to generate hydroxyl radicals and first superoxide radicals.

[0033] A radical conversion device for converting hydroxyl radicals into second superoxide radicals;

[0034] The sample is composed of a first hydrogen peroxide radical and a second hydrogen peroxide radical.

[0035] According to embodiments of this disclosure, the free radical generating apparatus includes:

[0036] Bubbling container, suitable for holding ultrapure water;

[0037] The zero-air generator is suitable for generating zero air and adjusting the flow rate of zero air so that the zero air can purge ultrapure water in a bubble container to obtain water molecules with a target concentration.

[0038] Quartz tubes are suitable for receiving water molecules from bubbling containers; and

[0039] An ultraviolet light source is used to irradiate water molecules inside a quartz tube, causing the water molecules to photolyze and generate hydroxyl radicals and first superoxide radicals.

[0040] According to embodiments of this disclosure, the free radical conversion apparatus includes:

[0041] The carbon monoxide supply unit is used to supply carbon monoxide to the free radical conversion device, so that the carbon monoxide reacts with hydroxyl radicals to generate a second superoxide radical.

[0042] The nitric oxide supply unit is used to supply nitric oxide to the chemical conversion device, so that the nitric oxide reacts with the first superoxide radical sample to generate gaseous nitrous acid.

[0043] According to embodiments of this disclosure, the correction system further includes:

[0044] Multiple flow controllers are used to regulate the gas flow rate in the free radical generator, free radical conversion unit, and chemical conversion unit;

[0045] Electrical control devices are used to electrically control free radical generating devices, free radical conversion devices, and chemical conversion devices to control the generation and conversion processes of free radicals.

[0046] Based on the above technical solution, the calibration method and calibration system for the superoxide radical detector provided in this disclosure have at least one of the following beneficial effects:

[0047] (1) In the embodiments of this disclosure, by quantitatively converting the superoxide radical sample into gaseous nitrous acid, the quantitative conversion of the non-steady-state radical into the steady-state nitrous acid is realized, and the standard concentration of superoxide radical in the sample can be indirectly calculated based on the detection concentration of gaseous nitrous acid.

[0048] (2) In the embodiments of this disclosure, the standard concentration and detection concentration of hydrogen superoxide radicals are linearly analyzed to obtain the corresponding correction coefficients, which can then be used to correct the response value during the testing process of the hydrogen superoxide radical detector, thereby effectively improving the accuracy of the hydrogen superoxide radical detector.

[0049] (3) In the embodiments of this disclosure, the first superoxide radical sample can be completely converted into gaseous nitrous acid. The loss of free radicals on the transmission tube wall is deducted, which can avoid the influence of free radical wall loss on the calibration results. Furthermore, a photometer is not required, which simplifies the operation steps of the calibration technique, helps to reduce costs and shorten the experimental time. Attached Figure Description

[0050] Figure 1 This is a flowchart of the method for calibrating the hydrogen superoxide radical detector in an embodiment of this disclosure;

[0051] Figure 2 This is a schematic diagram of the calibration system of the hydrogen superoxide radical detector in one embodiment of the present disclosure;

[0052] Figure 3 This is a schematic diagram of the calibration system of the superoxide radical detector in another embodiment of the present disclosure.

[0053] [Explanation of Labels in the Attached Image]

[0054] 100-Free Radical Generator;

[0055] 101-Zero Air Generator;

[0056] 102 - First electromagnetic three-way valve;

[0057] 1021 - First mass flow controller;

[0058] 1022 - Second mass flow controller;

[0059] 103 - Bubble container;

[0060] 104-Low-pressure mercury lamp;

[0061] 105-Quartz Tube;

[0062] 200-Free Radical Conversion Device;

[0063] 201 - Carbon monoxide supply unit;

[0064] 2011 - Third mass flow controller;

[0065] 202-Nitric oxide supply unit;

[0066] 2021 - Caustic soda asbestos;

[0067] 2022 - Fourth Mass Flow Controller;

[0068] 300-Chemical Conversion Unit;

[0069] 301 - Second electromagnetic three-way valve;

[0070] 400-HONO detector;

[0071] 401 - High-purity nitrogen supply unit;

[0072] 4011 - Fifth Mass Flow Controller;

[0073] 402 - Nitrite standard solution;

[0074] 500-Hydrogen superoxide radical detector;

[0075] 600 - Calibration Analysis Unit. Detailed Implementation

[0076] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0077] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein, indicate the presence of features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components. The terms “center,” “upper,” “lower,” “left,” “right,” “vertical,” “horizontal,” “inner,” “outer,” etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the purpose of facilitating and simplifying the description of the invention, 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 limiting the invention. Furthermore, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Unless otherwise expressly specified and limited, the terms “installed,” “connected,” and “linked” should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two components. For those skilled in the art, the specific meaning of the terms used in this invention will be understood on a case-by-case basis. All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification and not in an idealized or overly rigid way.

[0078] When using expressions such as "at least one of A, B, and C", they should generally be interpreted in accordance with the meaning that is commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B, and C, etc.).

[0079] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0080] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available. Methods not specifically described in the examples are conventional and can be performed according to the techniques or conditions described in the literature or the product instructions.

[0081] Figure 1 This is a flowchart of the superoxide radical detector calibration method in the embodiments of this disclosure.

[0082] like Figure 1 As shown, as one aspect of this disclosure, this disclosure provides a calibration method for a hydrogen superoxide radical detector, comprising steps S1 to S4.

[0083] Step S1: Convert the first superoxide radical sample into gaseous nitrous acid and obtain the concentration of gaseous nitrous acid;

[0084] Step S2: Based on the conversion relationship between the first hydrogen superoxide radical sample and gaseous nitrous acid, the standard concentration of hydrogen superoxide radicals is obtained;

[0085] Step S3: Use a hydrogen superoxide radical detector to detect the second hydrogen superoxide radical sample and obtain the detection concentration of hydrogen superoxide radicals;

[0086] Step S4: Calibrate the hydrogen superoxide radical detector according to the standard concentration and the detection concentration to obtain the calibrated hydrogen superoxide radical detector;

[0087] The first and second superoxide radical samples had the same concentration.

[0088] According to embodiments of this disclosure, the quantitative conversion of non-steady-state free radicals to steady-state nitrous acid is achieved by quantitatively converting a hydrogen superoxide radical sample into gaseous nitrous acid. The standard concentration of hydrogen superoxide radicals in the sample can be indirectly calculated based on the detected concentration of gaseous nitrous acid. Therefore, the hydrogen superoxide radical detector can be calibrated based on the relationship between the detected concentration and the standard concentration. Since the calibration process no longer relies on O2 and N2O chemiphotometers, but is based on the free radical conversion reaction with relatively few side reactions and the detection of steady-state nitrous acid, the experimental operation is simpler, the experimental time is shortened, and the calibration results are more accurate and reliable.

[0089] According to embodiments of this disclosure, step S4 may further include: performing linear analysis on the standard concentration and the detection concentration to obtain a correction coefficient; and correcting the response value of the hydrogen superoxide radical detector based on the correction coefficient.

[0090] According to embodiments of this disclosure, standard concentrations and detection concentrations of multiple sets of hydrogen superoxide radical samples with different concentrations can be tested and obtained separately. A linear equation is established based on these multiple standard and detection concentrations to obtain the relationship between the standard and detection concentrations, thereby yielding corresponding correction coefficients. By performing detection and linear analysis on multiple sets of samples, the obtained correction coefficients are more reliable.

[0091] Furthermore, after correcting the response value of the hydrogen superoxide radical detector according to the correction coefficient, the above steps S1 to S3 can be repeated to verify the corrected detector. During the verification process, the corresponding standard concentration and detection concentration are obtained. When the standard concentration and detection concentration are the same, it indicates that the calibration of the hydrogen superoxide radical detector is complete. When there is still a deviation between the standard concentration and the detection concentration, the above step S4 is repeated for calibration.

[0092] According to embodiments of this disclosure, the calibration method for the hydrogen superoxide radical detector may further include steps S001 to S002:

[0093] In step S001, a free radical sample containing hydroxyl radicals and first superoxide radicals is generated using a free radical generator.

[0094] In step S002, the hydroxyl radicals in the free radical sample are converted into second superoxide radicals;

[0095] The first superoxide radical sample or the second superoxide radical sample is composed of the first superoxide radical and the second superoxide radical.

[0096] According to the embodiments of this disclosure, step S001 may specifically include: introducing water molecules at a constant flow rate into a free radical generating device, as shown in the following formula (1), using a low-pressure mercury lamp to generate 184.9 nm ultraviolet light to irradiate water molecules, causing the water molecules to photolyze to generate hydroxyl radicals and hydrogen atoms. Other methods may be selected to provide ultraviolet light sources according to actual conditions.

[0097] H₂O + hv(184.9 nm) = OH + H (1)

[0098] Subsequently, hydrogen atoms react with oxygen to generate the first hydrogen superoxide radical, as shown in equation (2):

[0099] H + O₂ = HO₂ (2)

[0100] The hydroxyl radicals and superoxide radicals obtained from the above reaction constitute the radical sample.

[0101] According to embodiments of this disclosure, the concentration of free radicals generated can be controlled by adjusting the flow rate of water molecules introduced into the free radical generator, thereby obtaining a fixed concentration of hydrogen superoxide free radicals.

[0102] According to an embodiment of this disclosure, step S002 may specifically include: using carbon monoxide to react with hydroxyl radicals to convert hydroxyl radicals into second superoxide radicals, the reaction process being shown in the following formula (3):

[0103] CO + OH + O₂ = HO₂ + CO₂ (3)

[0104] According to embodiments of this disclosure, converting the first hydrogen superoxide radical sample into gaseous nitrous acid in step S1 may include:

[0105] The first superoxide radical sample was converted into gaseous nitrous acid by reacting excess nitric oxide with the first superoxide radical sample. Specifically, when the superoxide radical reacts with nitric oxide, hydroxyl radicals and nitrogen dioxide are generated. The hydroxyl radicals then react with excess nitric oxide to generate gaseous nitrous acid. The reaction process is shown in equations (4) and (5) below.

[0106] HO2 + NO = OH + NO2 (4)

[0107] OH + NO = HONO (5)

[0108] According to the embodiments of this disclosure, during the reaction of excess nitric oxide with the first superoxide radical sample, the superoxide radicals are completely converted into gaseous nitrous acid. It can be calculated that the concentration of gaseous nitrous acid is equal to the concentration of superoxide radicals, and the conversion relationship is shown in the following equation (6):

[0109] C = C1 (6)

[0110] Where C is the concentration of gaseous nitrous acid; C1 is the concentration of hydrogen superoxide free radicals.

[0111] Therefore, the standard concentration of hydrogen superoxide radicals can be obtained based on the detected concentration of gaseous nitrous acid according to this conversion relationship.

[0112] Figure 2 This is a schematic diagram of the calibration system of a hydrogen superoxide radical detector in one embodiment of this disclosure.

[0113] like Figure 2 As shown, as another aspect of this disclosure, a calibration system for a hydrogen superoxide radical detector based on the above-described calibration method is disclosed. The calibration system includes: a chemical conversion device 300, a gaseous nitrous acid (HONO) detector 400, a hydrogen superoxide (HO2) radical detector 500, and a calibration analysis unit 600.

[0114] Chemical conversion device 300 is used to convert the first hydrogen superoxide radical sample into gaseous nitrous acid;

[0115] The HONO gaseous nitrous acid detector 400 is used to detect the concentration of gaseous nitrous acid and obtain the concentration of gaseous nitrous acid.

[0116] The hydrogen superoxide (HO2) radical detector 500 is used to detect a second hydrogen superoxide radical sample and obtain the detection concentration of hydrogen superoxide radicals; and

[0117] The calibration analysis unit 600 is used to calibrate the hydrogen superoxide radical detector 500 according to the standard concentration and the detection concentration;

[0118] The first and second superoxide radical samples had the same concentration.

[0119] According to embodiments of this disclosure, a first superoxide radical sample is first introduced into a chemical conversion device 300, where it reacts with excess nitric oxide to quantitatively convert into gaseous nitrous acid. The gaseous nitrous acid is then sent to a gaseous nitrous acid detector 400 for detection, obtaining the detection concentration of the gaseous nitrous acid, thereby indirectly obtaining the standard concentration value of the first superoxide radical. Next, a second superoxide radical sample of the same concentration is introduced into a superoxide radical detector 500, and the corresponding detection concentration value is obtained. A calibration analysis unit 600 is then used to calibrate the superoxide radical detector 500 based on the linear relationship between the standard concentration and the detection concentration.

[0120] Figure 3 This is a schematic diagram of the calibration system of the superoxide radical detector in another embodiment of the present disclosure.

[0121] like Figure 3 As shown, the calibration system may also include a high-purity nitrogen supply unit 401 and a nitrous acid standard solution 402 connected to the gaseous nitrous acid detector 400 for calibrating the gaseous nitrous acid detector 400.

[0122] According to the embodiments of this disclosure, before performing the above-described calibration method steps S1 to S4, the controllers on the channels of the gaseous nitrous acid detector 400 and the high-purity nitrogen supply unit 401 can be turned on to allow high-purity nitrogen to be introduced into the gaseous nitrous acid detector 400 to obtain a detection zero point. Then, the gaseous nitrous acid detector 400 is calibrated using a nitrite standard sample of known concentration to obtain the relationship between the actual concentration of the nitrite standard sample and the detection concentration response value of the gaseous nitrous acid detector 400, so that the gaseous nitrous acid detector 400 can obtain test results with high accuracy.

[0123] According to embodiments of this disclosure, the correction system may further include: a free radical generating device 100 and a free radical conversion device 200. The free radical generating device 100 is used to photolyze water molecules to generate hydroxyl radicals and first superoxide radicals; the free radical conversion device 200 is used to convert the hydroxyl radicals into second superoxide radicals; wherein the first superoxide radical sample or the second superoxide radical sample is composed of the first superoxide radical and the second superoxide radical.

[0124] According to embodiments of this disclosure, such as Figure 3 As shown, the correction system may also include multiple flow controllers: a first mass flow controller 1021, a second mass flow controller 1022, a third mass flow controller 2011, a fourth mass flow controller 2022, and a fifth mass flow controller 4011, for regulating the gas flow of the free radical generator 100, the free radical conversion device 200, and the chemical conversion device 300.

[0125] According to an embodiment of this disclosure, before the calibration system is operated, the method further includes: turning on the second mass flow controller 1022, and adjusting the first electromagnetic three-way valve 102 to allow zero air to pass through the free radical generator 100, the free radical conversion device 200 and the chemical conversion device 300 once through the second mass flow controller 1022 to clean the calibration system. The cleaning process lasts for about 1 minute.

[0126] According to embodiments of this disclosure, reference is made to Figure 3 The free radical generating device 100 includes: a zero air generator 101, a bubbling container 103, a low-pressure mercury lamp 104, and a quartz tube 105. The low-pressure mercury lamp 104 is used to provide an ultraviolet light source, and other methods can be selected to provide an ultraviolet light source that can be used for photolysis of water molecules, depending on the actual situation.

[0127] According to an embodiment of this disclosure, in step S001 above, zero air is generated by the zero air generator 101 and the flow rate of the zero air is adjusted. The first electromagnetic three-way valve 102 and the first mass flow controller 1021 are adjusted so that the zero air blows through the ultrapure water in the bubbling container 103, carrying water molecules into the quartz tube 105. The low-pressure mercury lamp 104 is turned on to generate an ultraviolet light source of 184.9 nm. The ultraviolet light source irradiates the water molecules in the quartz tube 105, causing the water molecules to photolyze to generate hydroxyl radicals and first superoxide radicals.

[0128] According to embodiments of this disclosure, the free radical conversion device 200 includes: a carbon monoxide supply unit 201 and a nitric oxide supply unit 202, wherein the carbon monoxide supply unit 201 is used to supply carbon monoxide to the free radical conversion device 200, so that the carbon monoxide reacts with hydroxyl radicals to generate a second superoxide radical; the nitric oxide supply unit 202 is used to supply nitric oxide to the chemical conversion device 300, so that the nitric oxide reacts with a first superoxide radical sample to generate gaseous nitrous acid.

[0129] According to an embodiment of this disclosure, in step S002 above, by turning on the carbon monoxide supply unit 201, adjusting the third mass flow controller 2011, a quantitative amount of carbon monoxide is provided to react with hydroxyl radicals to generate hydrogen superoxide radicals, and adjusting the second electromagnetic three-way valve 302 to introduce the hydrogen superoxide radicals into the chemical conversion device 300.

[0130] According to an embodiment of this disclosure, in step S1 above, the nitric oxide supply unit 202 is turned on, allowing nitric oxide to pass through the caustic soda asbestos 2021 to remove nitrous acid from the nitric oxide standard gas, thus preventing nitrous acid or other impurity gases from affecting the detection results of the gaseous nitrous acid detector 400. When superoxide free radicals are introduced into the chemical conversion device 300, the fourth mass flow controller 2022 is adjusted to control the flow rate of nitric oxide into the chemical conversion device 300, so that the superoxide free radicals and nitric oxide react fully to generate gaseous nitrous acid.

[0131] According to an embodiment of the present disclosure, in step S2 above, the gaseous nitrous acid generated in the chemical conversion device 300 is passed into the gaseous nitrous acid detector 400 for detection to obtain the detection concentration of gaseous nitrous acid, and the standard concentration C1 of superoxide free radicals is indirectly obtained according to the concentration conversion relationship shown in formula (6).

[0132] According to an embodiment of this disclosure, in step S3 above, a second superoxide free radical sample with the same concentration is generated using a free radical generator 100 and a free radical conversion device 200. The second electromagnetic three-way valve 302 is adjusted to introduce the superoxide free radical into the superoxide free radical detector 500 to obtain the detection concentration C1' of the superoxide free radical.

[0133] According to embodiments of this disclosure, by progressively adjusting the first mass flow controller 1021, the flow rate of zero air through the bubbling container 103 is controlled to obtain water molecules with different concentration gradients. These water molecules are then photolyzed under ultraviolet light to generate free radicals of a fixed concentration, resulting in multiple sets of hydrogen superoxide free radicals with concentration gradients. These are then converted into multiple sets of gaseous nitrous acid with concentration gradients by a chemical conversion device 300. Detection of these gaseous nitrous acid sets indirectly yields the standard concentrations C1, C2, C3, C4, C5… of the multiple sets of hydrogen superoxide free radicals with concentration gradients. The corresponding concentrations of hydrogen superoxide free radicals are detected by a hydrogen superoxide free radical detector 500, obtaining the instrument's response values ​​for different concentrations of hydrogen superoxide free radicals, i.e., multiple detection concentrations C1', C2', C3', C4', C5'….

[0134] According to an embodiment of this disclosure, in step S4 above, the calibration analysis unit 600 is used to analyze the standard concentrations C1, C2, C3, C4, C5... and the detection concentrations C1', C2', C3', C4', C5'... of hydrogen superoxide radicals, establish a linear relationship between the standard concentrations and the detection concentrations, obtain relevant calibration coefficients, and calibrate the response value of the hydrogen superoxide radical detector 500 based on the calibration coefficients.

[0135] According to embodiments of this disclosure, the correction system further includes an electrical control device (not shown) for electrically controlling the free radical generating device, the free radical conversion device, and the chemical conversion device to control the generation and conversion process of free radicals.

[0136] Based on the above technical solution, the calibration method and system for the hydrogen nitrous oxide free radical detector provided in this disclosure quantitatively converts unsteady free radicals into steady-state nitrous acid through chemical conversion for concentration detection. The standard concentration of hydrogen nitrous oxide free radicals is indirectly obtained based on the conversion relationship, avoiding loss on the tube wall during free radical transport. The response value of the hydrogen nitrous oxide free radical detector is calibrated based on the standard concentration of hydrogen nitrous oxide free radicals, eliminating the need for a photometer, simplifying the calibration process, and controlling quantitative detection during the process, thus reducing the uncertainty of the detection results.

[0137] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of this disclosure. It should be understood that the above are only specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A calibration method for a hydrogen superoxide radical detector, comprising: The first superoxide radical sample was converted into gaseous nitrous acid to obtain the concentration of the gaseous nitrous acid; Based on the conversion relationship between the first hydrogen superoxide radical sample and the gaseous nitrous acid, the standard concentration of the hydrogen superoxide radical was obtained; The second superoxide radical sample was detected using a superoxide radical detector to obtain the concentration of the superoxide radicals. The hydrogen superoxide radical detector is calibrated according to the standard concentration and the detection concentration to obtain the calibrated hydrogen superoxide radical detector. The first hydrogen superoxide radical sample and the second hydrogen superoxide radical sample have the same concentration, and the first hydrogen superoxide radical sample and the second hydrogen superoxide radical sample are prepared by the following methods respectively: A free radical sample containing hydroxyl radicals and first superoxide radicals was generated using a free radical generator. The hydroxyl radicals in the radical sample are converted into second superoxide radicals by reacting carbon monoxide with the hydroxyl radicals. The first superoxide radical sample or the second superoxide radical sample is composed of the first superoxide radical and the second superoxide radical.

2. The calibration method for the hydrogen superoxide radical detector according to claim 1, wherein, The calibration of the hydrogen superoxide radical detector based on the standard concentration and the detection concentration includes: Linearity analysis was performed on the standard concentration and the detected concentration to obtain the correction coefficient; The response value of the superoxide radical detector is corrected according to the correction coefficient.

3. The calibration method for the hydrogen superoxide radical detector according to claim 1, wherein, The method of generating a free radical sample containing hydroxyl radicals and first superoxide radicals using a free radical generator includes: A constant flow rate of water molecules is introduced into a free radical generator. The water molecules are irradiated with 184.9 nm ultraviolet light generated by a low-pressure mercury lamp, causing the water molecules to photolyze and generate hydroxyl radicals and hydrogen atoms. The hydrogen atoms react with oxygen to generate the first hydrogen superoxide radical. The free radical sample is composed of the hydroxyl radical and the hydrogen superoxide radical.

4. The calibration method for the hydrogen superoxide radical detector according to claim 1, wherein, The process of converting the first hydrogen superoxide radical sample into gaseous nitrous acid includes: The first superoxide radical sample is converted into gaseous nitrous acid by reacting excess nitric oxide with the first superoxide radical sample.

5. A calibration system for a hydrogen superoxide radical detector based on the calibration method according to any one of claims 1 to 4, comprising: A chemical conversion device for converting a first superoxide radical sample into gaseous nitrous acid; A gaseous nitrous acid detector is used to detect the concentration of gaseous nitrous acid and obtain the concentration of gaseous nitrous acid. A hydrogen superoxide radical detector is used to detect a second hydrogen superoxide radical sample to obtain the detection concentration of the hydrogen superoxide radicals; and A calibration analysis unit is used to calibrate the hydrogen superoxide radical detector based on the standard concentration and the detection concentration. The first hydrogen superoxide radical sample and the second hydrogen superoxide radical sample have the same concentration.

6. The calibration system for the hydrogen superoxide radical detector according to claim 5 further includes: A free radical generator is used to photolyze water molecules to generate hydroxyl radicals and first superoxide radicals. as well as A free radical conversion device for converting the hydroxyl radical into a second superoxide radical; The first superoxide radical sample or the second superoxide radical sample is composed of the first superoxide radical and the second superoxide radical.

7. The calibration system for the hydrogen superoxide radical detector according to claim 6, wherein, The free radical generator includes: Bubbling container, suitable for holding ultrapure water; A zero-air generator is suitable for generating zero air and adjusting the flow rate of the zero air so that the zero air purges ultrapure water in the bubbling container to obtain water molecules with a target concentration. Quartz tube, suitable for receiving water molecules from the bubbling container; An ultraviolet light source is used to irradiate water molecules inside the quartz tube, causing the water molecules to photolyze and generate the hydroxyl radical and the first superoxide radical.

8. The calibration system for the hydrogen superoxide radical detector according to claim 6, wherein, The free radical conversion device includes: A carbon monoxide supply unit is used to supply carbon monoxide to the free radical conversion device, so that the carbon monoxide reacts with the hydroxyl radical to generate the second superoxide radical. A nitric oxide supply unit is used to supply nitric oxide to the chemical conversion device, so that the nitric oxide reacts with the first superoxide radical sample to generate the gaseous nitrous acid.

9. The calibration system for the hydrogen superoxide radical detector according to claim 6 further includes: Multiple flow controllers are used to regulate the gas flow rates of the free radical generator, the free radical conversion device, and the chemical conversion device; An electrical control device is used to electrically control the free radical generating device, the free radical conversion device, and the chemical conversion device to control the generation and conversion process of free radicals.

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