Simple analysis method for measuring content of hydrogen peroxide in hydrogen peroxide

Abstract

The invention discloses a simple analysis method for determining the content of hydrogen peroxide in hydrogen peroxide. According to the method, a differential scanning calorimeter (DSC) is adopted to analyze the thermal decomposition process of hydrogen peroxide at a specific heating scanning rate, the temperature and heat flow change of a sample in the heating process is recorded to obtain a DSC curve, the thermal decomposition and heat release peak area of hydrogen peroxide in hydrogen peroxide is integrated, and the thermal decomposition and heat release peak area of hydrogen peroxide in hydrogen peroxide is calculated. And establishing a standard curve of the hydrogen peroxide content and the peak area in the hydrogen peroxide so as to calculate the content of the hydrogen peroxide in the to-be-detected sample. According to the method, the operation steps for measuring the hydrogen peroxide content are simplified. The whole analysis process consumes less than 30 minutes, the determination time is shortened compared with a general method, and the method has the advantages of being independent of manpower and specific chemical reagents and instruments and high in accuracy.

Description

Technical Field

[0001] The invention belongs to the field of analytical technology, and particularly relates to a simple analytical method for determining the content of hydrogen peroxide in hydrogen peroxide. Background Art

[0002] Hydrogen peroxide (chemical formula H 2 O 2 ), also known as aqueous hydrogen peroxide, has strong oxidizing properties and can react with strong oxidants such as chlorine and potassium permanganate to show reducing properties. It is an important inorganic chemical raw material and is widely used in the fields of medicine, textiles, papermaking, and chemicals. Hydrogen peroxide with different hydrogen peroxide contents has different uses. For example, 6% hydrogen peroxide mixed with 0.005% methylene blue can be used for blood testing, and hydrogen peroxide greater than 10% is used as a bleaching agent and deodorizer in the textile, leather, paper, and wood manufacturing industries. Hydrogen peroxide has poor stability and is easily decomposed when exposed to heat, light, or contact with heavy metal ions, releasing oxygen and a large amount of heat energy, which can easily cause combustion and explosion. Therefore, accurate analysis of the content of hydrogen peroxide during the production process is crucial to ensure its stability and safety.

[0003] At present, the conventional methods for determining the content of hydrogen peroxide include chemical titration analysis, spectrophotometry, high performance liquid chromatography, electrochemical analysis, near infrared spectroscopy, etc. Among them, the chemical titration analysis method has low cost, simple instruments and equipment, and accurate results, but the operation time is long, there are many influencing factors, and it depends on the proficiency of the operator. Spectrophotometry has high detection sensitivity, simple operation, and the required instrument is a spectrophotometer, no other complex equipment is required, low cost, good selectivity, but poor sensitivity, and low stability of the measurement results. High performance liquid chromatography has the advantages of being simple and fast, high accuracy and sensitivity, and good reproducibility, but the liquid chromatograph used in this method is expensive, the sample pretreatment is relatively troublesome, and it must be operated by professionals, and it cannot be widely used in ordinary laboratories. Electrochemical analysis has high sensitivity and can detect low levels of hydrogen peroxide, but its selectivity is poor. Near infrared spectroscopy (NIR) is easy to automate and monitor online, but changes in temperature and humidity will affect its analysis accuracy.

[0004] In order to solve the problem of rapid and accurate analysis of hydrogen peroxide content, there is an urgent need for an analytical method with simple operation, high precision and high degree of automation to guide production, transportation and use. When determining its content, the existing determination method needs to add a variety of additives, and there are problems such as complex operation, long time consumption, and the accuracy of the results depends on the proficiency and experience of the operator, which limits its wide application in industrial production. For example, patent CN201910878584.5 uses the reaction of hydrogen peroxide and methylene blue to judge the content of hydrogen peroxide by observing the change in the color of the methylene blue solution. It is suitable for colorless water samples with a pH value of less than 6.5, resulting in certain limitations on the accuracy and repeatability of the results. Patent CN202211083011.1 and patent CN202310928927.0 use iodine titration to quickly detect the content of hydrogen peroxide in industrial hydrogen peroxide, but require specific chemical reagents and materials, increase costs and preparations, and require a certain amount of time to complete the preparation, titration and analysis process, which increases the determination time. Summary of the invention

[0005] The existing methods have the problems of complex operation, long time consumption and low accuracy of results when determining the content of hydrogen peroxide, which limits its wide application in industrial production. The purpose of the present invention is to provide a simple analytical method for determining the content of hydrogen peroxide in hydrogen peroxide, that is, using a differential scanning calorimeter (DSC) to analyze the thermal decomposition process of hydrogen peroxide at a specific heating scanning rate, recording the temperature and heat flow changes of the sample during the heating process, obtaining a DSC curve, integrating the thermal decomposition exothermic peak area of ​​hydrogen peroxide in hydrogen peroxide, establishing a standard curve of hydrogen peroxide content and peak area in hydrogen peroxide, and thus calculating the content of hydrogen peroxide in the hydrogen peroxide of the sample to be tested.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A simple analytical method for determining the content of hydrogen peroxide in hydrogen peroxide comprises the following steps:

[0008] (1) Accurately weigh a series of hydrogen peroxide standard samples with different hydrogen peroxide contents of equal mass;

[0009] (2) using a differential scanning calorimeter, the hydrogen peroxide standard sample is subjected to a temperature increase test in the range of 30 to 200° C. at a temperature increase scanning rate of 5 to 15° C. / min, the heat change of the sample is recorded, and a corresponding DSC curve is generated;

[0010] (3) integrating the peak area of ​​the DSC curve obtained in step (2) to obtain the thermal decomposition exothermic peak area As of hydrogen peroxide in hydrogen peroxide, and establishing a linear standard curve of hydrogen peroxide content c-thermal decomposition exothermic peak area As in hydrogen peroxide, with the hydrogen peroxide content c in hydrogen peroxide as the abscissa and the thermal decomposition exothermic peak area As in hydrogen peroxide as the ordinate;

[0011] (4) Accurately weigh an amount of the hydrogen peroxide sample to be tested that is equal to the amount of the hydrogen peroxide standard sample, obtain the corresponding DSC curve according to step (2), integrate the exothermic area to obtain As, and substitute As into the linear standard curve of hydrogen peroxide content c in hydrogen peroxide-thermal decomposition exothermic peak area As established in step (3) to obtain the content of hydrogen peroxide in the hydrogen peroxide sample to be tested.

[0012] In a specific embodiment, in step (1), the hydrogen peroxide content of the series of hydrogen peroxide standard samples ranges from 10wt% to 50wt%; for example, the series of hydrogen peroxide concentrations are 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, and 50wt%, respectively. In a specific embodiment, the weighing amount of each hydrogen peroxide standard sample is 80 to 120mg, for example, 100mg, and the weighing error is within ±0.5mg, and a 1 / 10,000 balance can be used for weighing.

[0013] In a specific embodiment, in step (2), the hydrogen peroxide standard sample is preferably scanned by heating in the range of 40 to 180°C.

[0014] In a specific implementation, in step (2), the hydrogen peroxide standard sample is subjected to a temperature increase test at a temperature increase scanning rate of 8 to 12°C / min; preferably, the hydrogen peroxide standard sample is subjected to a temperature increase test at a temperature increase scanning rate of 10°C / min.

[0015] In a specific embodiment, in step (2), the atmosphere for heating the sample using a differential scanning calorimeter is nitrogen, and the output pressure does not exceed 0.1 MPa, for example, 0.05 MPa to 0.06 MPa.

[0016] In a specific embodiment, in step (3), the linear standard curve of hydrogen peroxide content in hydrogen peroxide-thermal decomposition exothermic peak area As is established as As=1.94c+15.63, r 2 =0.9905, and its linear range is 10wt%≤c≤50wt%.

[0017] Beneficial effects of the technical solution of the present invention:

[0018] The present invention uses a differential scanning calorimeter (DSC) to analyze the thermal decomposition process of hydrogen peroxide with different hydrogen peroxide contents at a specific temperature rise scanning rate, thereby simplifying the operation steps for determining the content of hydrogen peroxide. The entire analysis process takes less than 30 minutes, which shortens the determination time compared to the general method, and has the advantages of being independent of manual labor and specific chemical reagents and instruments and having high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a typical DSC curve diagram of hydrogen peroxide with different hydrogen peroxide contents in Example 1.

[0020] Figure 2 It is a linear standard curve of the hydrogen peroxide content in hydrogen peroxide in Example 1-the thermal decomposition exothermic peak area As of hydrogen peroxide in hydrogen peroxide. DETAILED DESCRIPTION

[0021] The present invention solves the problems of complicated operation and long time consumption when determining the content of hydrogen peroxide in hydrogen peroxide, and adopts a differential scanning calorimeter (DSC) to analyze the thermal decomposition process of hydrogen peroxide with different contents at a specific heating scanning rate. The inventors found that under a specific temperature range and a specific heating rate, a differential scanning calorimeter (DSC) is used to analyze a hydrogen peroxide sample, and the obtained DSC peak area is integrated, and the obtained thermal decomposition exothermic peak area As of hydrogen peroxide in hydrogen peroxide is linearly related to the hydrogen peroxide content of the hydrogen peroxide sample, thereby establishing a simple analytical method for determining the content of hydrogen peroxide in hydrogen peroxide of the present invention.

[0022] In order to better understand the technical solution provided by the present invention, the present invention is described in detail below through specific implementation methods, but the claims of the present invention are not limited to these embodiments, and the embodiments only provide some experimental conditions for achieving the purpose of the present technical invention.

[0023] Unless otherwise specified, the raw materials, reagents, methods, etc. used in the examples are conventional raw materials, reagents, methods in the art.

[0024] Differential scanning calorimeter (DSC) was purchased from Hunan Sande Technology Co., Ltd., model: WS-C800A.

[0025] Hydrogen peroxide was obtained from Dongming Xuyang Chemical Co., Ltd.

[0026] Potassium permanganate was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0027] Sulfuric acid was purchased from Seika Industry Co., Ltd. The content of hydrogen peroxide in hydrogen peroxide herein refers to the mass percentage.

[0028] Example 1

[0029] (1) Use a 1 / 10,000 balance to accurately weigh 100 ± 0.5 mg of a standard sample of hydrogen peroxide containing 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, and 50 wt% hydrogen peroxide, and place it in a glass crucible of the DSC instrument.

[0030] (2) Turn on the power of the DSC instrument and set the corresponding parameters of the DSC, temperature range: 30-200°C, heating rate: 10°C / min, atmosphere: nitrogen, output pressure: 0.05MPa-0.06MPa; perform the heating test according to the set temperature program, automatically record the heat change of the sample, and generate the corresponding DSC curve. The DSC curve of the exemplary sample is shown in Figure 1 .

[0031] (3) After the test, the peak area of ​​the DSC curve obtained in step (2) is integrated to obtain the thermal decomposition exothermic peak area As of hydrogen peroxide in hydrogen peroxide. A linear standard curve of hydrogen peroxide content c-thermal decomposition exothermic peak area As is established with the hydrogen peroxide content c in hydrogen peroxide as the abscissa and the thermal decomposition exothermic peak area As in hydrogen peroxide as the ordinate. Figure 2 .

[0032] (4) Using a 1 / 10,000 balance, accurately weigh 100±0.5 mg of the hydrogen peroxide sample to be tested (see Table 1 for the hydrogen peroxide sample to be tested), perform detection according to step (2) to obtain the corresponding DSC curve, integrate the exothermic area to obtain As, substitute As into the standard curve established in step (3), and calculate the content of hydrogen peroxide in the hydrogen peroxide sample to be tested.

[0033] At the same time, in order to verify the accuracy of the DSC detection method of the present invention, the chemical titration method was used to perform three parallel measurements on the hydrogen peroxide sample to be tested. The chemical titration method is the mainstream detection method of the national standard method. In this method, hydrogen peroxide and potassium permanganate undergo an oxidation-reduction reaction in an acidic medium, and the content of hydrogen peroxide is calculated based on the consumption of the potassium permanganate standard titration solution. The steps are:

[0034] Weigh 100 mg of hydrogen peroxide sample and place it in a 250 mL conical flask with 100 mL of 98% mass concentration sulfuric acid solution. Titrate with about 0.1 mol / L potassium permanganate standard titration solution until the solution turns pink and does not disappear within 30 seconds. Calculate the concentration of hydrogen peroxide in the sample according to the following formula.

[0035] The calculation formula of hydrogen peroxide content in hydrogen peroxide is:

[0036] Where: w 1- the content of hydrogen peroxide in the hydrogen peroxide sample, wt%; v- the volume of the potassium permanganate standard titration solution consumed in the titration, unit: mL; c- the concentration of the potassium permanganate standard titration solution, unit: mol / L; M- the molar mass of hydrogen peroxide, 34.0147 g / mol; m- the mass of the hydrogen peroxide sample, unit: g.

[0037] The test results of the hydrogen peroxide samples are shown in Table 1.

[0038] Table 1.

[0039] Sample number to be tested National Standard Law DSC 1 10.54±0.21 10.18±0.10 2 28.14±0.18 27.93±0.13 3 48.82±0.20 48.26±0.09 4 2.66±0.24 5.21±1.07 5 55.23±0.15 62.45±4.22

[0040] As can be seen from Table 1, the results of the DSC analysis of the hydrogen peroxide content in hydrogen peroxide in the present invention are very consistent with the results obtained by the national standard method. There is no significant difference between the two methods for hydrogen peroxide samples (samples 1-3) with a hydrogen peroxide content within 10 to 50 wt%. When the content exceeds this range, the accuracy of the DSC method decreases.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A simple analytical method for determining the content of hydrogen peroxide in hydrogen peroxide, comprising the following steps: (1) Accurately weigh a series of hydrogen peroxide standard samples with different hydrogen peroxide contents of equal mass; (2) using a differential scanning calorimeter, the hydrogen peroxide standard sample is subjected to a temperature increase test in the range of 30 to 200° C. at a temperature increase scanning rate of 5 to 15° C. / min, the heat change of the sample is recorded, and a corresponding DSC curve is generated; (3) integrating the peak area of ​​the DSC curve obtained in step (2) to obtain the thermal decomposition exothermic peak area As of hydrogen peroxide in hydrogen peroxide, and establishing a linear standard curve of hydrogen peroxide content c-thermal decomposition exothermic peak area As in hydrogen peroxide, with the hydrogen peroxide content c in hydrogen peroxide as the abscissa and the thermal decomposition exothermic peak area As in hydrogen peroxide as the ordinate; (4) Accurately weigh an amount of the hydrogen peroxide sample to be tested that is equal to the amount of the hydrogen peroxide standard sample, obtain the corresponding DSC curve according to step (2), integrate the exothermic area to obtain As, and substitute As into the linear standard curve of hydrogen peroxide content c in hydrogen peroxide-thermal decomposition exothermic peak area As established in step (3) to obtain the content of hydrogen peroxide in the hydrogen peroxide sample to be tested.

2. The method according to claim 1, characterized in that In step (1), the hydrogen peroxide content of the series of hydrogen peroxide standard samples ranges from 10 wt % to 50 wt %.

3. The method according to claim 1, characterized in that In step (1), the weighing amount of each hydrogen peroxide standard sample is 80-120 mg, and the weighing error is within ±0.5 mg.

4. The method according to claim 3, characterized in that In step (1), the weighing amount of each hydrogen peroxide standard sample is 100 mg, and the weighing error is within ±0.5 mg.

5. The method according to claim 1, characterized in that In step (2), the hydrogen peroxide standard sample is scanned by heating in the range of 40 to 180°C.

6. The method according to claim 1, characterized in that In step (2), the hydrogen peroxide standard sample is subjected to a temperature increase test at a temperature increase scanning rate of 8 to 12° C. / min.

7. The method according to claim 1, characterized in that In step (2), the hydrogen peroxide standard sample is subjected to a temperature increase test at a temperature increase scanning rate of 10° C. / min.

8. The method according to claim 1, characterized in that In step (2), the atmosphere for the temperature rise test of the sample using a differential scanning calorimeter is nitrogen, and the output pressure does not exceed 0.1 MPa.

9. The method according to claim 8, characterized in that The output pressure is 0.05MPa~0.06MPa.

10. The method according to claim 1, characterized in that In step (3), the linear standard curve of hydrogen peroxide content in hydrogen peroxide-thermal decomposition exothermic peak area As is established as As = 1.94c + 15.63, r 2 =0.9905, and its linear range is 10wt%≤c≤50wt%.

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