A method for quantitatively detecting hydroquinone

Abstract

The present invention relates to a method for quantitatively detecting hydroquinone. This method applies the "NaClO₂ - C₄H₁₃NO (tetramethylammonium hydroxide) - Na₂S₄O₆" clock system, that is, the Chlorite - Ammonium - Tetrathionate (CAT) clock reaction system as the detection solution. According to the different responses of this system to hydroquinone at different concentrations, that is, the different induction times, the quantitative analysis of hydroquinone is achieved. The method for quantitatively analyzing hydroquinone involved in the present invention has the characteristics of high accuracy, easy operation, convenience and rapidity, etc.

Description

Technical Field

[0001] The present invention relates to an analytical detection method, specifically to establish a "NaClO2 - C4H 13 NO (tetramethylammonium hydroxide) - Na2S4O6" clock system, that is, the Chlorite - Ammonium - Tetrathionate clock system (hereinafter referred to as the CAT clock system). According to the different responses of this system to hydroquinone with different concentrations, that is, different induction times, a quantitative analysis method for hydroquinone is realized, belonging to the field of analytical chemistry. Background Art

[0002] Hydroquinone, also known as: 1,4 - benzenediol; hydroquinone; its structural formula is as shown in (Ⅰ). White needle crystals. It is readily soluble in hot water, ethanol and ether, and slightly soluble in benzene. It is an important chemical raw material. In recent years, the domestic demand for it has shown an increasing trend, and the consumption fields have been expanding year by year. 1,4 - Benzenediol is widely used and is an important raw material, intermediate and additive in pharmaceuticals, pesticides, dyes and rubber, etc. It is mainly used in developers, anthraquinone dyes, azo dyes, rubber antioxidants and monomer inhibitors, food stabilizers and paint antioxidants, petroleum anticoagulants, synthetic ammonia catalysts, etc. The application fields of hydroquinone are gradually expanding. In addition to the applications in traditional fields, there are also new developments in fields such as chemical fertilizers, water treatment, and liquid crystal polymers. In addition, it can also be processed into other fine chemicals, such as 1,4 - diamino leuco body, quinizarin, etc. Hydroquinone is an intermediate for herbicides such as quizalofop - ethyl, haloxyfop - methyl, thiazopyr, fenoxaprop - ethyl, haloxyfop - pyrid, lactofen, and is also an intermediate for pharmaceuticals and dyes.

[0003] The determination of hydroquinone mainly uses instrumental analysis methods, such as high - performance liquid chromatography (HPLC), high - performance liquid chromatography with ultraviolet detection (HPLC - UV). There are also reports on determination methods such as iodometry, photometry, fluorescence method, and chemiluminescence method. Chromatography has the advantages of high sensitivity and good accuracy, but for samples with complex matrices, the analysis sensitivity decreases. Therefore, it is very necessary to find a detection method with good detection effect and simple and rapid operation.

[0004]

[0005] Structural formula (Ⅰ) Hydroquinone Summary of the Invention

[0006] The present invention aims to provide a new quantitative detection method for hydroquinone, that is, with "NaClO2 - C4H 13The "NaClO2 - C4H NO - Na2S4O6" CAT clock system is a method for quantitatively detecting hydroquinone in a solution. This method is a standard curve (working curve) method developed based on the sensitive response of this CAT clock system to hydroquinone. Specifically, the "NaClO2 - C4H 13 NO - Na2S4O6" CAT clock reaction system is used as the detection solution, and the graph of pH change over time is recorded; when the CAT clock reaction starts, equal - volume series of hydroquinone sample solutions with different concentrations to be detected are added to the CAT clock system respectively; according to the different induction times generated by the system when the concentrations of the solution to be detected in the CAT clock system are different, the quantitative detection of the hydroquinone sample to be detected is achieved.

[0007] A working curve is established based on the relationship between the concentration of hydroquinone in the CAT clock system and the induction time, where the abscissa is the concentration of hydroquinone in the CAT clock system and the ordinate is the induction time t; when the concentration of hydroquinone in the system is between 4.44×10 -8 mol / L and 1.33×10 -7 mol / L, the induction time t has a linear relationship with the concentration of hydroquinone, and based on this, the quantitative detection of hydroquinone in the sample can be achieved.

[0008] The difference between this quantitative detection method and the prior art is that this invention uses the "NaClO2 - C4H 13 NO - Na2S4O6" CAT clock system as the detection solution, and due to the different responses of this system to hydroquinone with different concentrations, that is, different induction times, the quantitative analysis of hydroquinone is achieved.

[0009] The detected concentration range of hydroquinone in the detection solution (CAT clock system) is 4.44×10 -8 mol / L to 1.33×10 -7 mol / L.

[0010] When hydroquinone is detected in the detection solution (CAT clock system), the temperature of the CAT clock system is controlled at 23 ± 0.5 °C.

[0011] Using the above - mentioned CAT clock system, the detectable concentration range of hydroquinone is the optimal concentration range determined through experiments. Within this concentration range, the induction time has a good response to the change in hydroquinone concentration, and the linear correlation coefficient is large. In addition, the concentration ranges of each component in the detection solution (CAT clock system) are shown in Table 1, and the optimal concentrations of the detection solution (CAT clock system) obtained through multiple experiments are shown in Table 2:

[0012] Table 1: Concentrations of each component in the CAT clock system

[0013] <![CDATA[NaClO2 (mol / L)]]> <![CDATA[C4H 13 NO (tetramethylammonium hydroxide) (mol / L)]]> <![CDATA[Na2S4O6 (mol / L)]]> 0.01-0.02 0.00021-0.0004 0.0012-0.0019

[0014] Table 2: Optimal Concentrations of Each Component in the CAT Clock System

[0015] <![CDATA[NaClO2 (mol / L)]]> <![CDATA[C4H 13 NO (tetramethylammonium hydroxide) (mol / L)]]> <![CDATA[Na2S4O6 (mol / L)]]> 0.01067 0.0003889 0.001556

[0016] The specific experimental steps are as follows:

[0017] 1. Prepare a detection solution (CAT clock system) within the concentration range specified in Table 1, and control its temperature at 23 ± 0.5 °C. Insert the prepared working electrode (pH composite electrode, Leici, E-331) into the solution. Connect the other end of the working electrode to a computer through a potential / temperature / pH comprehensive tester (Jiaxing Disheng Electronic Technology Co., Ltd., ZHFX-595). After setting the acquisition time and sampling rate in the chemical signal acquisition and analysis program on the computer, quickly click the start button to monitor the pH of the solution. The computer records the curve of the collected pH changing with time, which is the CAT clock spectrum. When detecting a substance, quickly add the substance to be detected simultaneously when the CAT clock system reaction starts, and record the CAT clock spectrum of the pH changing with time in the same way.

[0018] The basic parameters of the CAT clock spectrum include:

[0019] Induction time: The time required for the pH to stabilize from the start of the CAT clock system reaction.

[0020] pH jump range: The pH corresponding to the start of the pH jump in the system to the pH corresponding to the end of the pH jump.

[0021] 2. Establish a working curve for the relationship between the concentration of hydroquinone in the detection solution and the pH induction time

[0022] Prepare a series of low-concentration hydroquinone solutions as sample solutions with distilled water as the solvent. At the same time as the CAT clock system reaction starts, use a pipette to add 20 μL of the above series of sample solutions with different concentrations to 45 mL of the CAT clock system respectively, so that the concentration of hydroquinone in the system is between 4.44×10 -8 mol / L - 1.33×10 -7 mol / L; The change amount of the CAT clock system response is the induction time, denoted as t; When the concentration of hydroquinone in the system is different, the induction time t of the CAT clock system is also different; Plot a graph with the concentration of hydroquinone in the system as the abscissa and t as the ordinate; When the concentration of hydroquinone in the system is between 4.44×10 -8 mol / L - 1.33×10 -7When it is between

[0023] 3. Quantitative detection of hydroquinone

[0024] When a test sample with an unknown concentration is added to the detection solution (CAT clock system) at the beginning of the reaction of the CAT clock system, the corresponding induction time (t) of the CAT clock system can be measured. According to the corresponding relationship between t and the concentration on the working curve, the concentration of hydroquinone in the detection system can be obtained, and then the concentration of hydroquinone in the test sample can be calculated. Description of the drawings

[0025] Figure 1 It is the graph of the change of the pH value of the detection solution (CAT clock system) with time when no test sample is added in Example 1.

[0026] Figure 2 It is in Example 1, after adding 1.33×10 -7 mol / L of hydroquinone, the graph of the change of the pH value of the detection solution (CAT clock system) with time.

[0027] Figure 3 It is in Example 1, after adding 1.11×10 -7 mol / L of hydroquinone, the graph of the change of the pH value of the detection solution (CAT clock system) with time.

[0028] Figure 4 It is the working curve between the pH induction time t and the hydroquinone concentration in Example 1.

[0029] Figure 5 It is the graph of the change of the pH value of the detection solution (CAT clock system) with time when no test sample is added in Example 2.

[0030] Figure 6 It is in Example 2, after adding 8.89×10 -8 mol / L of hydroquinone, the graph of the change of the pH value of the detection solution (CAT clock system) with time.

[0031] Figure 7 It is in Example 2, after adding 6.67×10 -8 mol / L of hydroquinone, the graph of the change of the pH value of the detection solution (CAT clock system) with time.

[0032] Figure 8 It is the working curve between the pH induction time t and the hydroquinone concentration in Example 2.

[0033] Figure 9It is the graph of the change in the pH value of the detection solution (CAT clock system) over time when no test sample is added in Example 3.

[0034] Figure 10 It is the graph of the change in the pH value of the detection solution (CAT clock system) over time after adding 1.33×10 -7 mol / L hydroquinone in Example 3.

[0035] Figure 11 It is the graph of the change in the pH value of the detection solution (CAT clock system) over time after adding 4.44×10 -8 mol / L hydroquinone in Example 3.

[0036] Figure 12 It is the working curve between the pH induction time t and the hydroquinone concentration in Example 3. Embodiment Example 1

[0037] Apply the CAT clock system with “NaClO2 - C4H 13 NO - Na2S4O6” as the substrate as the detection solution to quantitatively analyze hydroquinone. Add equal - volume hydroquinone sample solutions with different concentrations to the CAT clock system to establish a working curve (such as a linear relationship) between the hydroquinone concentration and the induction time in the detection system, so as to achieve the purpose of detecting hydroquinone in the CAT clock system, and then calculate the concentration of hydroquinone in the test sample.

[0038] (1) Prepare the detection solution

[0039] First, prepare 0.02 mol / L NaClO2 solution, 0.0025 mol / L C4H 13 NO and 0.005 mol / L Na2S4O6 solutions with distilled water respectively. Add 25 mL NaClO2 solution, 5 mL 0.02 mol / L C4H 13 NO solution, and 15 mL 0.005 mol / L Na2S4O6 solution to a 50 - mL small beaker in sequence to ensure that the concentrations of each component in the “NaClO2 - C4H 13 NO - Na2S4O6” CAT clock system are NaClO2 0.01111 mol / L, C4H 13 NO 0.0002778 mol / L, and Na2S4O6 0.001667 mol / L, with a total volume of 45 mL and the temperature controlled at 23 °C.

[0040] Meanwhile, using distilled water as the solvent, a series of hydroquinone sample solutions with different concentrations were prepared.

[0041] (2)Obtain the CAT clock diagram

[0042] The diagram of the change in the pH value of the prepared detection solution over time was recorded by a computer equipped with a chemical signal acquisition and analysis program (without adding the detection sample). As Figure 1 shown. The pH induction time was 1463 s as a blank control. Another two groups of detection solutions with the same component concentrations as the above detection solution were prepared. For one group, simultaneously at the start of the reaction, 20 μL of 0.0003 mol / L hydroquinone sample solution was added to the 45 mL CAT clock system, such that the concentration of hydroquinone in the detection solution was 1.33×10 -7 mol / L, and the added hydroquinone shortened the induction time to 935 s as Figure 2 shown; for the other group, simultaneously at the start of the reaction, 20 μL of 0.00025 mol / L hydroquinone sample solution was added to the 45 mL CAT clock system, such that the concentration of hydroquinone in the detection solution was 1.11×10 -7 mol / L, and the added hydroquinone changed the induction time to 995 s as Figure 3 shown. Figure 2 、 Figure 3 It was confirmed that different concentrations of hydroquinone in the detection solution led to different induction times in the CAT clock system. When the concentration of hydroquinone in the detection system was between 4.44×10 -8 mol / L - 1.33×10 -7 mol / L, the results of different induction times caused by different concentrations could be observed.

[0043] (3)Quantitative detection

[0044] According to the relationship between the concentration of hydroquinone in the detection system and the induction time, a working curve was established, as Figure 4 shown, where the abscissa is the concentration of hydroquinone in the CAT clock system, and the ordinate is the induction time t. When the concentration of hydroquinone in the detection system was between 4.44×10 -8 mol / L - 1.33×10 -7 mol / L, the induction time and the concentration of hydroquinone showed a linear relationship, and the linear equation was t = -3×10 9 c + 1317.5, R 2 = 0.9972. Based on this, quantitative detection of hydroquinone in the sample can be achieved. Example 2

[0045] (1) Preparation of the detection solution

[0046] First, prepare 0.02 mol / L NaClO2 solution, 0.0025 mol / L C4H 13 NO, and 0.005 mol / L Na2S4O6 solution with distilled water respectively. Add 24.0 mL NaClO2 solution, 7 mL 0.02 mol / L C4H 13 NO solution, and 14 mL 0.005 mol / L Na2S4O6 solution into a 50 mL small beaker in sequence to ensure that the concentrations of each component in the "NaClO2 - C4H 13 NO - Na2S4O6" CAT clock system are NaClO2 0.01067 mol / L, C4H 13 NO 0.0003889 mol / L, and Na2S4O6 0.001556 mol / L, with a total volume of 45 mL, and the temperature is controlled at 23 °C.

[0047] Meanwhile, prepare a series of hydroquinone sample solutions with different concentrations using distilled water as the solvent.

[0048] (2)Obtaining the CAT clock spectrogram

[0049] The spectrogram of the pH value of the prepared detection solution changing with time is recorded by a computer equipped with a chemical signal acquisition and analysis program (without adding the detection sample). As Figure 5 shown. The pH induction time is 1464 s as a blank control. Prepare another two groups of detection solutions with the same concentrations of each component as the above detection solution. For one group, at the same time as the reaction starts, add 20 μL of 0.0002 mol / L hydroquinone sample solution to the 45 mL CAT clock system, so that the concentration of hydroquinone in the detection solution is 8.89×10 -8 mol / L, and the added hydroquinone makes the induction time shorten to 1070 s as Figure 6 shown; for the other group, at the same time as the reaction starts, add 20 μL of 0.00015 mol / L hydroquinone sample solution to the 45 mL CAT clock system, so that the concentration of hydroquinone in the detection solution is 6.67×10 -8 mol / L, and the added hydroquinone makes the induction time become 1130 s as Figure 7 shown. Figure 6 、 Figure 7 It is confirmed that different concentrations of hydroquinone in the detection solution lead to different induction times in the CAT clock system. When the concentration of hydroquinone in the detection system is in the range of 4.44×10 -8 mol / L - 1.33×10 -7When it is between

[0050] (3) Quantitative detection

[0051] A working curve is established according to the relationship between the concentration of hydroquinone in the detection system and the induction time. As Figure 8 shown, where the abscissa is the concentration of hydroquinone in the CAT clock system, and the ordinate is the induction time t. When the concentration of hydroquinone in the detection system is between 4.44×10 -8 mol / L - 1.33×10 -7 mol / L, the induction time and the concentration of hydroquinone are linearly related, and the linear equation is t = -3×10 9 c + 1323.8, R 2 = 0.9987. Based on this, the quantitative detection of hydroquinone in the sample can be achieved. Example 3

[0052] (1) Preparation of detection solution

[0053] First, prepare 0.02 mol / L NaClO2 solution, 0.0025 mol / L C4H 13 NO and 0.005 mol / L Na2S4O6 solution with distilled water. Add 26.0 mL NaClO2 solution, 6 mL 0.02 mol / L C4H 13 NO solution, and 13 mL 0.005 mol / L Na2S4O6 solution to a 50 mL small beaker in sequence to ensure that the concentrations of each component in the "NaClO2 - C4H 13 NO - Na2S4O6" CAT clock system are NaClO2 0.01156 mol / L, C4H 13 NO 0.0003333 mol / L, Na2S4O6 0.001444 mol / L, the total volume is 45 mL, and the temperature is controlled at 23 °C.

[0054] At the same time, prepare a series of hydroquinone sample solutions with different concentrations using distilled water as the solvent.

[0055] (2) Obtaining the CAT clock map

[0056] The map of the pH value change of the prepared detection solution over time is recorded by a computer equipped with a chemical signal acquisition and analysis program (without adding the detection sample). As Figure 9As shown. The pH induction time is 1467 s as a blank control. Another two groups of detection solutions with the same component concentrations as the above detection solution were prepared. For one group, at the same time as the reaction started, 20 μL of 0.0003 hydroquinone sample solution was added to 45 mL of the CAT clock system, so that the concentration of hydroquinone in the detection solution was 1.33×10 -7 mol / L, and the added hydroquinone shortened the induction time to 936 s as Figure 10 shown; for the other group, at the same time as the reaction started, 20 μL of 0.0001 mol / L hydroquinone sample solution was added to 45 mL of the CAT clock system, so that the concentration of hydroquinone in the detection solution was 4.44×10 -8 mol / L, and the added hydroquinone changed the induction time to 1190 s as Figure 11 shown. Figure 10 , Figure 11 It was confirmed that different concentrations of hydroquinone in the detection solution led to different induction times in the CAT clock system. When the concentration of hydroquinone in the detection system was between 4.44×10 -8 mol / L - 1.33×10 -7 mol / L, the results of different induction times caused by different concentrations could be observed in the CAT clock system.

[0057] (3) Quantitative detection

[0058] According to the relationship between the concentration of hydroquinone in the detection system and the induction time, a working curve was established, as Figure 12 shown, where the abscissa is the concentration of hydroquinone in the CAT clock system, and the ordinate is the induction time t. When the concentration of hydroquinone in the detection system was between 4.44×10 -8 mol / L - 1.33×10 -7 mol / L, the induction time and the concentration of hydroquinone showed a linear relationship, and the linear equation was t = -3×10 9 c + 1329.8, R 2 = 0.993. Based on this, the quantitative detection of hydroquinone in the sample can be achieved.

Claims

1. A quantitative detection method for hydroquinone, characterized in that: Prepare a solution of the sample hydroquinone to be tested using distilled water as solvent; Application of "NaClO2-C4H 13 NO-Na2S4O6" CAT clock reaction system was used as the detection solution, in which C4H 13 NO represents tetramethylammonium hydroxide, and a graph of pH changes over time is recorded. The CAT clock system temperature is controlled within the range of 23±0.5°C. When the CAT clock reaction begins, equal volumes of a series of different concentrations of the sample solution to be tested, hydroquinone, are added to the CAT clock system. Quantitative detection of the sample to be tested is achieved based on the different induction times generated by the system at different concentrations of the test solution in the CAT clock system. The induction time is the time required from the start of the CAT clock reaction to pH stabilization. A working curve was established based on the relationship between the concentration of hydroquinone in the test solution in the CAT clock system and the induction time, where the horizontal axis is the concentration of hydroquinone in the test solution in the CAT clock system and the vertical axis is the induction time t. When the concentration of hydroquinone in the system is 4.44×10 -8 mol / L to 1.33×10 -7 When the concentration of hydroquinone is between 0.1% and 0.2%, there is a linear relationship between the induction time t and the concentration of hydroquinone, based on which the quantitative detection of hydroquinone in the sample can be achieved; The molar concentration range of each component in the test solution is: NaClO2 0.01-0.02mol / L, C4H 13 NO 0.00021-0.0004mol / L, Na2S4O6 0.0012-0.0019mol / L.

2. The quantitative detection method according to claim 1, wherein: The molar concentrations of the components in the test solution are NaClO2 0.01067mol / L, C4H 13 NO 0.0003889mol / L, Na2S4O60.001556mol / L.

3. The quantitative detection method according to claim 1, wherein: The temperature of the CAT clock system was controlled at 23°C when detecting the hydroquinone solution.

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