A method for determining manganese tetraoxide chloride ion

Abstract

The present invention discloses a method for determining chloride ions in manganese tetraoxide, including sample preparation, preparation of a chlorine standard solution, drawing of a standard curve, analysis and detection, and result calculation. The method adopts spectrophotometry, and effectively reduces the influence of interfering ions by accurately preparing a standard solution and adjusting the pH value, thereby improving the accuracy and repeatability of the detection. The method is suitable for the trace detection of chloride ions in soft ferrite raw materials in the electronics industry, has the advantages of simple operation, high efficiency, and environmental friendliness, and is of great significance for improving product quality and ensuring the performance of electronic components.

Description

Technical Field

[0001] The invention relates to the field of measurement, and in particular to a method for determining manganese tetraoxide chloride ions. Background Art

[0002] Manganese tetraoxide plays a vital role in the electronics industry. It is the main raw material for the production of soft ferrites. Soft ferrites are made by mixing manganese, zinc and iron oxides in a specific ratio and sintering. The material properties include a narrow remanent magnetic induction curve, which allows for multiple magnetizations. At the same time, its DC resistivity is extremely high, which effectively prevents eddy current losses. Soft ferrites are widely used in electronic components such as storage cores, disks and tapes for electronic computers, transformers and high-quality inductors for telephones, flyback transformers for televisions, magnetic heads for magnetic recording, inductors, magnetic amplifiers, saturated inductors, and antenna rods.

[0003] At present, there is no special national standard method for the detection of chloride ions in manganese tetraoxide. The general method for chloride determination provided by the existing national standard GB / T 9729-2007 is the visual turbidimetry. This method is based on the fact that chloride ions react with silver ions in a nitric acid medium to generate insoluble silver chloride. When the chloride ion content is low, the silver chloride remains suspended for a certain period of time, resulting in turbidity of the solution, so the chloride is determined by visual turbidimetry.

[0004] Although the existing mesh turbidimetry can meet the demand of chloride ion detection in manganese tetraoxide to a certain extent, there are some significant disadvantages in this method. First, the mesh turbidimetry depends on the subjective judgment of the operator, and there may be large visual recognition differences between different operators, resulting in poor consistency and repeatability of the test results. Secondly, the method has high skill requirements for the operator, and professional training is required to accurately judge the turbidity of the solution, which increases the difficulty of operation and training costs to a certain extent. In addition, the mesh turbidimetry is less efficient when processing a large number of samples, which is not suitable for the needs of high-throughput detection. Moreover, the method has a limited detection range for chloride ion concentration, and when the chloride ion concentration is lower than a certain threshold, the change of turbidity is not obvious, and it is difficult to accurately measure. Finally, the mesh turbidimetry may affect the test results when environmental conditions (such as light, temperature) change, resulting in data instability. Therefore, these shortcomings limit the scope of application and accuracy of mesh turbidimetry in the detection of chloride ions in manganese tetraoxide, and it is urgent to develop more accurate, efficient and stable detection technology. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for determining manganese tetraoxide chloride ions.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for determining manganese tetraoxide chloride ions of the present invention comprises the following steps:

[0008] Sample preparation:

[0009] Weigh 1g of sample to an accuracy of 0.0002g and transfer it into a 100mL beaker;

[0010] Add 10 mL of 1+1 nitric acid solution and 2 mL of 30% by volume hydrogen peroxide solution, heat and dissolve for 30 minutes to obtain a mixed solution;

[0011] Transfer the mixed solution to a 100 mL volumetric flask, dilute to the mark, and shake well to obtain a sample solution;

[0012] Preparation of chlorine standard solution:

[0013] Prepare a 100 μg / mL chlorine standard solution. The specific steps are as follows: pipette 10 mL of 1000 μg / mL chlorine standard solution into a 100 mL volumetric flask, dilute to the mark with pure water, and shake well;

[0014] Standard curve drawing:

[0015] Pipette 0mL, 1mL, 2mL, 3mL, 4mL and 5mL of 100μg / mL chlorine standard solution into a 100mL volumetric flask, dilute to the mark with pure water, and the theoretical chloride ion contents are 0.00%, 0.01%, 0.02%, 0.03%, 0.04% and 0.05% respectively;

[0016] Analysis and testing:

[0017] Accurately transfer 25 mL of chlorine standard solution and sample solution into a 50 mL colorimetric tube;

[0018] Add 10 mL of 0.5% silver nitrate solution and 2.5 mL of 1+1 nitric acid solution, shake well, and place in dark place for 15 minutes;

[0019] Use a colorimetric dish and pure water as a reference to measure the absorbance, and find out the chloride ion concentration in the sample solution according to the standard curve;

[0020] Calculation results:

[0021] The chloride ion content is calculated according to the following formula, expressed as mass fraction ω, and the value is in %:

[0022]

[0023] in:

[0024] ρ: mass concentration of chloride ions in the test solution, in μg / mL;

[0025] V: total volume of test solution, in mL;

[0026] m: sample mass, in g.

[0027] The present invention proposes a complete analytical method for determining chloride ions in manganese tetraoxide, the steps of which include sample preparation, preparation of a chlorine standard solution, drawing of a standard curve, analytical detection and result calculation. The method is based on accurate sample mass and standard solution configuration, combined with chemical dissolution and dilution steps, and determines the chloride ion concentration by colorimetric analysis technology. The method ensures the repeatability and accuracy of the determination process, and is particularly suitable for detecting trace chloride ions in manganese tetraoxide.

[0028] Furthermore, the standard curve drawing comprises the following steps:

[0029] Prepare the required materials: 100 μg / mL chlorine standard solution, 6 100 mL volumetric flasks, precision pipettes with capacities of 1 mL, 2 mL, 3 mL, 4 mL, and 5 mL, and pure water for constant volume;

[0030] Label the volumetric flasks: Label the six 100mL volumetric flasks as "0mL", "1mL", "2mL", "3mL", "4mL", and "5mL" to distinguish each group of solutions;

[0031] Transfer the standard solution: Use a pipette to transfer the following volumes from the 100 μg / mL chlorine standard solution: 0 mL to the volumetric flask marked with "0 mL"; 1 mL to the volumetric flask marked with "1 mL"; 2 mL to the volumetric flask marked with "2 mL"; 3 mL to the volumetric flask marked with "3 mL"; 4 mL to the volumetric flask marked with "4 mL"; 5 mL to the volumetric flask marked with "5 mL";

[0032] Volume adjustment: Add pure water to each volumetric flask until it is close to the 90mL mark, and stir gently with a glass rod to mix; use a dropper to add pure water drop by drop to the mark on the volumetric flask, making sure the liquid level is level with the mark;

[0033] Shake the solution: Shake the solution in each volumetric flask thoroughly to ensure uniform solution concentration;

[0034] Calculation of theoretical chloride ion content: Calculate the theoretical mass concentration of chloride ions in each volumetric flask based on the volume of the 100 μg / mL standard solution transferred, in μg / mL, and then convert it to theoretical mass fraction:

[0035] 0mL: Theoretical content is 0.00%;

[0036] 1mL: (1mL×100μg / mL) / 100mL=1.00μg / mL=0.01%;

[0037] 2mL: (2mL×100μg / mL) / 100mL=2.00μg / mL=0.02%;

[0038] 3mL: (3mL×100μg / mL) / 100mL=3.00μg / mL=0.03%;

[0039] 4mL: (4mL×100μg / mL) / 100mL=4.00μg / mL=0.04%;

[0040] 5mL: (5mL×500μg / mL) / 100mL=1.00μg / mL=0.05%.

[0041] The above content describes the process of drawing a standard curve, including the preparation of standard solutions, solution dilution, and calculation of theoretical mass concentration of chloride ions. By gradually taking different volumes of chlorine standard solution and diluting them to the same total volume, the standard curve provides a benchmark for subsequent sample analysis. Clear dilution and volume determination operations improve the reliability of the curve, while the accurate calculation of the theoretical mass fraction lays the foundation for the determination of chloride ion concentration.

[0042] Furthermore, the analysis and detection comprises the following steps:

[0043] Pipette the solution: Use a precision pipette to pipette 25 mL of the chlorine standard solution and sample solution respectively, and add them into the marked 50 mL colorimetric tubes;

[0044] Add reagents: Add the following reagents to each colorimetric tube: 10 mL of 0.5% silver nitrate solution, 2.5 mL of 1+1 nitric acid solution;

[0045] Mix the solution: flick the tube with your finger or seal the tube with a stopper, and gently shake the tube to mix the solution evenly;

[0046] Light-proof reaction: Place the colorimetric tube in a light-shielding box or dark room and let it stand for 15 minutes to allow the reaction to proceed fully;

[0047] Measure absorbance: Turn on the spectrophotometer, set the wavelength to 430nm, and preheat the equipment to a stable state;

[0048] Fill the cuvette with pure water, which is used as the reference solution, and calibrate the zero-point absorbance;

[0049] Transfer the completed standard solution and sample solution into a cuvette with a 2 cm optical path, measure the absorbance of each solution, and record the results;

[0050] Find the chloride ion concentration: Draw a standard curve of absorbance and chlorine concentration based on the absorbance data of the standard solution; substitute the absorbance value of the sample solution into the standard curve to find its corresponding chloride ion concentration.

[0051] The above content describes the detailed process of sample analysis and detection, including solution transfer, reagent addition, light-proof reaction and absorbance measurement. Silver chloride precipitation is generated by adding silver nitrate and nitric acid to the sample and standard solution, and the change in absorbance is used to characterize the chloride ion content in the solution. The use of a spectrophotometer improves the sensitivity of the detection, and the standard curve provides a tool for quantifying chloride ions.

[0052] Furthermore, the pH value of the prepared sample is controlled between 1 and 2 to ensure the stable presence of chloride ions and the accuracy of detection. The low pH environment not only helps to prevent chloride ions from being volatilized or consumed by reactions, but also reduces the influence of interference factors on the experimental results. This requirement further ensures the specificity of chloride ion determination.

[0053] Furthermore, after the sample preparation step is completed, in order to ensure the specificity of the detection of chloride ions and suppress the influence of other interfering ions, a background interference control step is provided, including the following steps:

[0054] Adjust pH value: Use 1+1 nitric acid to adjust the pH of the sample solution to the range of 1-2 to inhibit the interference reaction of carbonate ions, because carbonate ions are converted into carbon dioxide gas and escape in a strong acidic environment; controlling acidity can avoid excessive acidification affecting other reactions;

[0055] Add masking agent: add 0.01 mol / L ammonium molybdate solution to the sample solution to mask phosphate ions; molybdate and phosphate form a stable ammonium phosphomolybdate complex, thereby reducing the interference of phosphate on the reaction of silver nitrate;

[0056] Add 5% barium chloride solution to precipitate and remove sulfate ions to form barium sulfate, and then remove the precipitate through a microporous filter or centrifugal device.

[0057] In order to eliminate the influence of interfering ions on chloride ion detection, background interference control steps are proposed, including pH adjustment and masking agent addition. Through strict acidity control and the addition of reagents such as ammonium molybdate and barium chloride, the interference of carbonate, phosphate and sulfate ions can be effectively suppressed to ensure the specificity and accuracy of the detection. These steps improve the operation process of the entire determination method, making the method more reliable and accurate.

[0058] The beneficial effects of the present invention are:

[0059] Improve accuracy: Through precise sample preparation and standard solution preparation, combined with spectrophotometric absorbance measurement, this method can accurately determine the chloride ion content in manganese tetraoxide, effectively reducing the uncertainty of human error and subjective judgment.

[0060] Enhanced repeatability: This method uses standard curve drawing and instrument detection to ensure the high repeatability of the experimental results, so that the tests performed by different operators or at different times can obtain consistent results.

[0061] Improve detection efficiency: Compared with the traditional eye-type turbidimetry, this method significantly improves the detection efficiency through automated measurement by spectrophotometer, and is particularly suitable for the detection of high-throughput samples.

[0062] Expand the detection range: This method can detect lower concentrations of chloride ions and can accurately determine trace amounts of chloride ions in manganese tetraoxide, thus broadening the application range of the detection.

[0063] Reduce interference: By adjusting the pH value and controlling interfering ions, this method effectively reduces the interference of other ions on chloride ion detection and improves the specificity of detection.

[0064] Transparent testing process: The steps of this method are detailed and easy to operate, making the entire testing process more transparent and convenient for quality control and management.

[0065] Environmentally friendly: This method reduces the use of chemical reagents and reduces the impact on the environment during the experiment.

[0066] In summary, this patent provides an efficient, accurate and reliable method for the determination of chloride ions in manganese tetraoxide, which is not only suitable for scientific research and product quality control, but also provides important technical support for the production of soft magnetic ferrites in the electronics industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 : Standard curve 1;

[0068] Figure 2 : Standard curve 2;

[0069] Figure 3 : Standard curve 3;

[0070] Figure 4 : Standard curve 4;

[0071] Figure 5 : Standard curve 5;

[0072] Figure 6 :The results of chloride ion standard curve detected by ion chromatography;

[0073] Figure 7:The results of ion chromatography testing of manganese tetraoxide 001;

[0074] Figure 8 :The results of ion chromatography testing of manganese tetraoxide 002;

[0075] Fig. 9 :The results of ion chromatography testing of manganese tetraoxide 003;

[0076] Fig.10 :The results of ion chromatography testing of manganese tetraoxide 004;

[0077] Fig.11 :The results of ion chromatography testing of manganese tetraoxide 005;

[0078] Fig.12 : Process flow chart of the present invention. DETAILED DESCRIPTION

[0079] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

[0080] Embodiment: The present invention proposes a novel method for determining chloride ions in manganese tetraoxide. The method innovatively adopts spectrophotometry to replace the traditional visual colorimetry, and uses a 2 cm quartz cuvette to measure absorbance at a specific wavelength of 430 nm. By equipping a standard chloride ion solution to construct a standard curve, the chloride ion concentration can be quickly and accurately obtained by simply substituting the sample absorbance value into the curve. Compared with traditional chemical detection methods, this method is more energy-saving and environmentally friendly, and represents the cutting-edge trend of analytical technology.

[0081] The present invention fundamentally solves the problem of chloride ion detection, and the test result is presented in the form of absorbance, which is more intuitive. By drawing a standard curve, a linear relationship between the content of the standard substance and the absorbance is established. This relationship can be directly established by a spectrophotometer, or completed using tools such as a function calculator and a computer. When the linear relationship R value reaches or exceeds 0.999, the accuracy of the detection can be ensured; if it is not reached, it is necessary to check the possible errors introduced and repeat the operation. Finally, an accurate chloride ion concentration value can be obtained through the standard curve.

[0082] Compared with visual turbidimetry, this method realizes the transformation of test results from semi-quantitative to fully quantitative, requires less skill from operators, and greatly reduces the impact of system errors and human errors on test results. The transformation from chemical analysis to instrumental analysis makes the test results more reliable and convincing.

[0083] Specifically: A method for determining manganese tetraoxide chloride ions comprises the following steps:

[0084] Sample preparation:

[0085] Weigh 1g of sample to an accuracy of 0.0002g and transfer it into a 100mL beaker;

[0086] Add 10 mL of 1+1 nitric acid solution and 2 mL of 30% by volume hydrogen peroxide solution, heat and dissolve for 30 minutes to obtain a mixed solution;

[0087] Transfer the mixed solution to a 100 mL volumetric flask, dilute to the mark, and shake well to obtain a sample solution;

[0088] Preparation of chlorine standard solution:

[0089] Prepare a 100 μg / mL chlorine standard solution. The specific steps are as follows: pipette 10 mL of 1000 μg / mL chlorine standard solution into a 100 mL volumetric flask, dilute to the mark with pure water, and shake well;

[0090] Standard curve drawing:

[0091] Pipette 0mL, 1mL, 2mL, 3mL, 4mL and 5mL of 100μg / mL chlorine standard solution into a 100mL volumetric flask, dilute to the mark with pure water, and the theoretical chloride ion contents are 0.00%, 0.01%, 0.02%, 0.03%, 0.04% and 0.05% respectively;

[0092] Analysis and testing:

[0093] Accurately transfer 25 mL of chlorine standard solution and sample solution into a 50 mL colorimetric tube;

[0094] Add 10 mL of 0.5% silver nitrate solution and 2.5 mL of 1+1 nitric acid solution, shake well, and place in dark place for 15 minutes;

[0095] Use a colorimetric dish and pure water as a reference to measure the absorbance, and find out the chloride ion concentration in the sample solution according to the standard curve;

[0096] Calculation results:

[0097] The chloride ion content is calculated according to the following formula, expressed as mass fraction ω, and the value is in %:

[0098]

[0099] in:

[0100] ρ: mass concentration of chloride ions in the test solution, in μg / mL;

[0101] V: total volume of test solution, in mL;

[0102] m: sample mass, in g.

[0103] The present invention proposes a complete analytical method for determining chloride ions in manganese tetraoxide, the steps of which include sample preparation, preparation of a chlorine standard solution, drawing of a standard curve, analytical detection and result calculation. The method is based on accurate sample mass and standard solution configuration, combined with chemical dissolution and dilution steps, and determines the chloride ion concentration by colorimetric analysis technology. The method ensures the repeatability and accuracy of the determination process, and is particularly suitable for detecting trace chloride ions in manganese tetraoxide.

[0104] Furthermore, the standard curve drawing comprises the following steps:

[0105] Prepare the required materials: 100 μg / mL chlorine standard solution, 6 100 mL volumetric flasks, precision pipettes with capacities of 1 mL, 2 mL, 3 mL, 4 mL, and 5 mL, and pure water for constant volume;

[0106] Label the volumetric flasks: Label the six 100mL volumetric flasks as "0mL", "1mL", "2mL", "3mL", "4mL", and "5mL" to distinguish each group of solutions;

[0107] Transfer the standard solution: Use a pipette to transfer the following volumes from the 100 μg / mL chlorine standard solution: 0 mL to the volumetric flask marked with "0 mL"; 1 mL to the volumetric flask marked with "1 mL"; 2 mL to the volumetric flask marked with "2 mL"; 3 mL to the volumetric flask marked with "3 mL"; 4 mL to the volumetric flask marked with "4 mL"; 5 mL to the volumetric flask marked with "5 mL";

[0108] Volume adjustment: Add pure water to each volumetric flask until it is close to the 90mL mark, and stir gently with a glass rod to mix; use a dropper to add pure water drop by drop to the mark on the volumetric flask, making sure the liquid level is level with the mark;

[0109] Shake the solution: Shake the solution in each volumetric flask thoroughly to ensure uniform solution concentration;

[0110] Calculation of theoretical chloride ion content: Calculate the theoretical mass concentration of chloride ions in each volumetric flask based on the volume of the 100 μg / mL standard solution transferred, in μg / mL, and then convert it to theoretical mass fraction:

[0111] 0mL: Theoretical content is 0.00%;

[0112] 1mL: (1mL×100μg / mL) / 100mL=1.00μg / mL=0.01%;

[0113] 2mL: (2mL×100μg / mL) / 100mL=2.00μg / mL=0.02%;

[0114] 3mL: (3mL×100μg / mL) / 100mL=3.00μg / mL=0.03%;

[0115] 4mL: (4mL×100μg / mL) / 100mL=4.00μg / mL=0.04%;

[0116] 5mL: (5mL×500μg / mL) / 100mL=1.00μg / mL=0.05%.

[0117] The above content describes the process of drawing a standard curve, including the preparation of standard solutions, solution dilution, and calculation of theoretical mass concentration of chloride ions. By gradually taking different volumes of chlorine standard solution and diluting them to the same total volume, the standard curve provides a benchmark for subsequent sample analysis. Clear dilution and volume determination operations improve the reliability of the curve, while the accurate calculation of the theoretical mass fraction lays the foundation for the determination of chloride ion concentration.

[0118] Furthermore, the analysis and detection comprises the following steps:

[0119] Pipette the solution: Use a precision pipette to pipette 25 mL of the chlorine standard solution and sample solution respectively, and add them into the marked 50 mL colorimetric tubes;

[0120] Add reagents: Add the following reagents to each colorimetric tube: 10 mL of 0.5% silver nitrate solution, 2.5 mL of 1+1 nitric acid solution;

[0121] Mix the solution: flick the tube with your finger or seal the tube with a stopper, and gently shake the tube to mix the solution evenly;

[0122] Light-proof reaction: Place the colorimetric tube in a light-shielding box or dark room and let it stand for 15 minutes to allow the reaction to proceed fully;

[0123] Measure absorbance: Turn on the spectrophotometer, set the wavelength to 430nm, and preheat the equipment to a stable state;

[0124] Fill the cuvette with pure water, which is used as the reference solution, and calibrate the zero-point absorbance;

[0125] Transfer the completed standard solution and sample solution into a cuvette with a 2 cm optical path, measure the absorbance of each solution, and record the results;

[0126] Find the chloride ion concentration: Draw a standard curve of absorbance and chlorine concentration based on the absorbance data of the standard solution; substitute the absorbance value of the sample solution into the standard curve to find its corresponding chloride ion concentration.

[0127] The above content describes the detailed process of sample analysis and detection, including solution transfer, reagent addition, light-proof reaction and absorbance measurement. Silver chloride precipitation is generated by adding silver nitrate and nitric acid to the sample and standard solution, and the change in absorbance is used to characterize the chloride ion content in the solution. The use of a spectrophotometer improves the sensitivity of the detection, and the standard curve provides a tool for quantifying chloride ions.

[0128] Furthermore, the pH value of the prepared sample is controlled between 1 and 2 to ensure the stable presence of chloride ions and the accuracy of detection. The low pH environment not only helps to prevent chloride ions from being volatilized or consumed by reactions, but also reduces the influence of interference factors on the experimental results. This requirement further ensures the specificity of chloride ion determination.

[0129] Furthermore, after the sample preparation step is completed, in order to ensure the specificity of the detection of chloride ions and suppress the influence of other interfering ions, a background interference control step is provided, including the following steps:

[0130] Adjust pH value: Use 1+1 nitric acid to adjust the pH of the sample solution to the range of 1-2 to inhibit the interference reaction of carbonate ions, because carbonate ions are converted into carbon dioxide gas and escape in a strong acidic environment; controlling acidity can avoid excessive acidification affecting other reactions;

[0131] Add masking agent: add 0.01 mol / L ammonium molybdate solution to the sample solution to mask phosphate ions; molybdate and phosphate form a stable ammonium phosphomolybdate complex, thereby reducing the interference of phosphate on the reaction of silver nitrate;

[0132] Add 5% barium chloride solution to precipitate and remove sulfate ions to form barium sulfate, and then remove the precipitate through a microporous filter or centrifugal device.

[0133] In order to eliminate the influence of interfering ions on chloride ion detection, background interference control steps are proposed, including pH adjustment and masking agent addition. Through strict acidity control and the addition of reagents such as ammonium molybdate and barium chloride, the interference of carbonate, phosphate and sulfate ions can be effectively suppressed to ensure the specificity and accuracy of the detection. These steps improve the operation process of the entire determination method, making the method more reliable and accurate.

[0134] The following is a comparative experiment of five samples numbered as trimanganese tetraoxide 001, trimanganese tetraoxide 002, trimanganese tetraoxide 003, trimanganese tetraoxide 004 and trimanganese tetraoxide 005, using the method of the present invention and the ion chromatography method. When the method provided by the present invention is used, five consecutive measurements are made and the average value is taken as the final result. The data are as follows:

[0135] Data of standard curve 1:

[0136] standard Absorbance Theoretical content% STD1 0.006 0 STD2 0.065 0.01 STD3 0.135 0.02 STD4 0.191 0.03 STD5 0.247 0.04 STD6 0.309 0.05

[0137] Standard curve 1 is attached Figure 1 ;

[0138] Determination results of manganese tetraoxide 001:

[0139]

[0140]

[0141] Data of standard curve 2:

[0142] standard Absorbance Theoretical content% STD1 0.012 0 STD2 0.072 0.01 STD3 0.132 0.02 STD4 0.195 0.03 STD5 0.252 0.04 STD6 0.306 0.05

[0143] Standard curve 2 is attached Figure 2 ;

[0144] Determination results of manganese tetraoxide 002:

[0145]

[0146] Data of standard curve 3:

[0147] standard Absorbance Theoretical content% STD1 0.005 0 STD2 0.059 0.01 STD3 0.117 0.02 STD4 0.184 0.03 STD5 0.239 0.04 STD6 0.294 0.05

[0148] Standard curve 3 is attached Figure 3 ;

[0149] Determination results of manganese tetraoxide 003:

[0150]

[0151]

[0152] Data of standard curve 4:

[0153] standard Absorbance Theoretical content% STD1 0.005 0 STD2 0.059 0.01 STD3 0.117 0.02 STD4 0.184 0.03 STD5 0.239 0.04 STD6 0.294 0.05

[0154] Standard curve 4 is attached Figure 4 ;

[0155] Determination results of manganese tetraoxide 004:

[0156]

[0157] Data of standard curve 5:

[0158] standard Absorbance Theoretical content% STD1 0.017 0 STD2 0.078 0.01 STD3 0.139 0.02 STD4 0.196 0.03 STD5 0.255 0.04 STD6 0.311 0.05

[0159] Standard curve 5 is attached Figure 5 ;

[0160] Determination results of manganese tetraoxide 005:

[0161]

[0162] Ion chromatography was used for detection. The detection results of the chloride ion standard curve are shown in the attached Figure 6 , the test results of manganese tetroxide 001-005 are attached Figure 7-11 ;

[0163] 5 sets of data detection comparison table, the comparison data are as follows:

[0164] Serial number Sample No. The method of the present invention Ion chromatography % error% 1 Manganese tetraoxide 001 0.035 0.0345 0.0005 2 Manganese tetraoxide 002 0.028 0.0276 0.0004 3 Manganese tetraoxide 003 0.0211 0.0217 0.0006 4 Manganese tetraoxide 004 0.0193 0.0198 0.0005 5 Manganese tetraoxide 005 0.0172 0.0176 0.0004

[0165] It can be seen that by conducting comparative experiments on the same sample using two different methods, the experimental results meet the requirements of precision and accuracy.

[0166] In addition, a feasibility experiment was conducted on the method of the present invention by calculating the spike recovery rate. The specific experiment is as follows: 1 mL, 2 mL, and 3 mL of a 100 ug / mL chloride ion standard substance were added to the sample numbered manganese tetraoxide 006, and parallel samples were made:

[0167] Data of standard curve 6:

[0168] standard Absorbance Theoretical content% STD1 0.015 0 STD2 0.124 0.02 STD3 0.239 0.04 STD4 0.345 0.06 STD5 0.468 0.08

[0169] The recovery rate test data table of manganese tetraoxide 006 sample is as follows:

[0170]

[0171] It can be seen that the recovery rate in the sample was calculated by the spike recovery method, and the average value of the spike recovery rate was 98.11%, which was in line with the required range of recovery rate, and the spike recovery verification was feasible.

[0172] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for determining manganese tetraoxide chloride ion, characterized in that: The following steps are involved: Sample preparation: Weigh 1g of sample to an accuracy of 0.0002g and transfer it into a 100mL beaker; Add 10 mL of 1+1 nitric acid solution and 2 mL of 30% by volume hydrogen peroxide solution, heat and dissolve for 30 minutes to obtain a mixed solution; Transfer the mixed solution to a 100 mL volumetric flask, dilute to the mark, and shake well to obtain a sample solution; Preparation of chlorine standard solution: Prepare a 100 μg / mL chlorine standard solution. The specific steps are as follows: pipette 10 mL of 1000 μg / mL chlorine standard solution into a 100 mL volumetric flask, dilute to the mark with pure water, and shake well; Standard curve drawing: Pipette 0mL, 1mL, 2mL, 3mL, 4mL and 5mL of 100μg / mL chlorine standard solution into a 100mL volumetric flask, dilute to the mark with pure water, and the theoretical chloride ion contents are 0.00%, 0.01%, 0.02%, 0.03%, 0.04% and 0.05% respectively; Analysis and testing: Accurately transfer 25 mL of chlorine standard solution and sample solution into a 50 mL colorimetric tube; Add 10 mL of 0.5% silver nitrate solution and 2.5 mL of 1+1 nitric acid solution, shake well, and place in dark place for 15 minutes; Use a colorimetric dish and pure water as a reference to measure the absorbance, and find out the chloride ion concentration in the sample solution according to the standard curve; Calculation results: The chloride ion content is calculated according to the following formula, expressed as mass fraction ω, and the value is in %: in: ρ: mass concentration of chloride ions in the test solution, in μg / mL; V: total volume of test solution, in mL; m: sample mass, in g.

2. The method for determining manganese tetraoxide chloride ion according to claim 1, wherein: Described standard curve drawing comprises the following steps: Prepare the required materials: 100 μg / mL chlorine standard solution, 6 100 mL volumetric flasks, precision pipettes with capacities of 1 mL, 2 mL, 3 mL, 4 mL, and 5 mL, and pure water for constant volume; Label the volumetric flasks: Label the six 100mL volumetric flasks as "0mL", "1mL", "2mL", "3mL", "4mL", and "5mL" to distinguish each group of solutions; Transfer the standard solution: Use a pipette to transfer the following volumes from the 100 μg / mL chlorine standard solution: 0 mL to the volumetric flask marked with "0 mL"; 1 mL to the volumetric flask marked with "1 mL"; 2 mL to the volumetric flask marked with "2 mL"; 3 mL to the volumetric flask marked with "3 mL"; 4 mL to the volumetric flask marked with "4 mL"; 5 mL to the volumetric flask marked with "5 mL"; Volume adjustment: Add pure water to each volumetric flask until it is close to the 90mL mark, and stir gently with a glass rod to mix; use a dropper to add pure water drop by drop to the mark on the volumetric flask, making sure the liquid level is level with the mark; Shake the solution: Shake the solution in each volumetric flask thoroughly to ensure uniform solution concentration; Calculation of theoretical chloride ion content: Calculate the theoretical mass concentration of chloride ions in each volumetric flask based on the volume of the 100 μg / mL standard solution transferred, in μg / mL, and then convert it to theoretical mass fraction: 0mL: Theoretical content is 0.00%; 1mL: (1mL×100μg / mL) / 100mL=1.00μg / mL=0.01%; 2mL: (2mL×100μg / mL) / 100mL=2.00μg / mL=0.02%; 3mL: (3mL×100μg / mL) / 100mL=3.00μg / mL=0.03%; 4mL: (4mL×100μg / mL) / 100mL=4.00μg / mL=0.04%; 5mL: (5mL×500μg / mL) / 100mL=1.00μg / mL=0.05%.

3. The method for determining manganese tetraoxide chloride ion according to claim 1, wherein: The analysis and detection comprises the following steps: Pipette the solution: Use a precision pipette to pipette 25 mL of the chlorine standard solution and sample solution respectively, and add them into the marked 50 mL colorimetric tubes; Add reagents: Add the following reagents to each colorimetric tube: 10 mL of 0.5% silver nitrate solution, 2.5 mL of 1+1 nitric acid solution; Mix the solution: flick the tube with your finger or seal the tube with a stopper, and gently shake the tube to mix the solution evenly; Light-proof reaction: Place the colorimetric tube in a light-shielding box or dark room and let it stand for 15 minutes to allow the reaction to proceed fully; Measure absorbance: Turn on the spectrophotometer, set the wavelength to 430nm, and preheat the equipment to a stable state; Fill the cuvette with pure water, which is used as the reference solution, and calibrate the zero-point absorbance; Transfer the completed standard solution and sample solution into a cuvette with a 2 cm optical path, measure the absorbance of each solution, and record the results; Find the chloride ion concentration: Draw a standard curve of absorbance and chlorine concentration based on the absorbance data of the standard solution; substitute the absorbance value of the sample solution into the standard curve to find its corresponding chloride ion concentration.

4. A method for determining manganese tetraoxide chloride ion as described in any one of claims 1 to 3, characterized in that: The pH value of the prepared sample is controlled between 1 and 2 to ensure the stable existence of chloride ions and the accuracy of detection.

5. A method for determining manganese tetraoxide chloride ion as claimed in claim 4, characterized in that: After the sample preparation step is completed, in order to ensure the specificity of the detection of chloride ions and suppress the influence of other interfering ions, a background interference control step is set, including the following steps: Adjust pH value: Use 1+1 nitric acid to adjust the pH of the sample solution to the range of 1-2 to inhibit the interference reaction of carbonate ions, because carbonate ions are converted into carbon dioxide gas and escape in a strong acidic environment; controlling acidity can avoid excessive acidification affecting other reactions; Add masking agent: add 0.01 mol / L ammonium molybdate solution to the sample solution to mask phosphate ions; molybdate and phosphate form a stable ammonium phosphomolybdate complex, thereby reducing the interference of phosphate on the reaction of silver nitrate; Add 5% barium chloride solution to precipitate and remove sulfate ions to form barium sulfate, and then remove the precipitate through a microporous filter or centrifugal device.

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