A method for detecting hydroquinone in water using chemiluminescence

Abstract

The present invention discloses a method for detecting hydroquinone in water using chemiluminescence. The chemiluminescence system consists of hydroquinone, peroxydisulfate, and sodium hydroxide. The core of the present invention is that when hydroquinone is added to a mixed solution of peroxydisulfate and sodium hydroxide, chemiluminescence can be generated, and the intensity of the chemiluminescence is positively correlated with the concentration of hydroquinone. A feature of the present invention is that the constructed hydroquinone-peroxydisulfate-sodium hydroxide chemiluminescence method does not require the addition of an additional fluorescent agent, and hydroquinone plays the dual role of a co-reactant and a luminescent agent. The chemiluminescence of the present invention can be used for the selective detection of hydroquinone.

Description

Technical Field

[0001] The invention belongs to the technical field of chemiluminescence, and in particular relates to a method for detecting hydroquinone in water by utilizing chemiluminescence. Background Art

[0002] Hydroquinone, a polyphenolic compound with a certain reducing property, can be used as a raw material for developing agents and antioxidants. It is also used in industrial fields such as biomedicine and papermaking, resulting in its widespread presence in environmental water samples and soil. However, hydroquinone is toxic to the human body, has a strong corrosive effect on the skin and mucous membranes, can damage the liver, and has a suppressive effect on the central nervous system. Therefore, many countries and regions consider it an environmental pollutant. Therefore, it is of great significance to develop a method for the rapid and accurate quantitative detection of hydroquinone under environmental conditions.

[0003] Currently, the main methods for determining hydroquinone include high-performance liquid chromatography, fluorescence spectrophotometry, spectrophotometry, electrochemical methods, and chemiluminescence. Chemiluminescence is increasingly favored due to its advantages, including simple instrumentation, wide linear range, low detection limit, and rapid analysis. Previous studies have constructed various chemiluminescence systems for the detection of hydroquinone. These chemiluminescence detection platforms primarily rely on the stimulatory or inhibitory effects of hydroquinone on the chemiluminescence system signal to indirectly determine the hydroquinone content. However, this strategy often results in complex systems requiring the simultaneous presence of multiple components (such as luminescent agents, co-reactants, catalysts, and hydroquinone). This significantly reduces the system's resistance to interference and makes it difficult to achieve selective detection of hydroquinone. For example, the presence of o-catechol, which has similar physicochemical properties, severely impacts the signals of most chemiluminescence systems, making it difficult to distinguish between hydroquinone and o-catechol. Summary of the Invention

[0004] In view of this, the present invention aims to provide a method for detecting hydroquinone in water using chemiluminescence. This method can directly use hydroquinone as a chemiluminescent reagent without the need for an additional fluorescent agent to achieve selective detection of hydroquinone. The method specifically comprises the following steps:

[0005] Step 1, preparing several hydroquinone reaction solutions with different concentration gradients; preparing peroxydisulfate and sodium hydroxide reaction solutions; Step 2, mixing equal volumes of the peroxydisulfate reaction solution and the sodium hydroxide reaction solution prepared in step 1;

[0006] Step 3: Using a static injection device, the multiple hydroquinone reaction solutions prepared in step 1 are mixed with the mixed solution obtained in step 2 in equal volumes in a reaction tank. A series of chemical reactions occur at the moment of mixing: hydroquinone first reacts with sodium hydroxide to produce semiquinone free radicals; then, the semiquinone free radicals react with peroxydisulfate to produce sulfate free radicals; finally, the sulfate free radicals oxidize the hydroquinone to produce chemiluminescent substances, thereby generating chemiluminescence; the intensity of the generated chemiluminescence is detected and recorded by a chemiluminescence instrument; the maximum chemiluminescence intensity is read and recorded as CL max ;

[0007] Step 4: Use the logarithm of hydroquinone concentration as the horizontal axis and CL as the horizontal axis in the graphing software. max The logarithm of the value is the vertical axis, and the logarithm of the hydroquinone concentration in the solution when the chemical reaction occurs in step 3, the number of CL obtained in step 3 max The logarithm of the value is plotted as a scatter plot, CL max The relationship between the value and the concentration of hydroquinone satisfies the relationship: lg(CL max )=a×lg(hydroquinone concentration)+b, thus obtaining the description of CL max A linear expression is formed between the logarithm of the value and the logarithm of the hydroquinone concentration; wherein, the values ​​of constants a and b (a>0, b≥0) can be solved by inserting a quadratic polynomial curve into the scatter plot;

[0008] Step 5: Determine the corresponding CL of the water sample to be tested according to step 3. max value; the obtained CL max The value is substituted into the linear expression in step 4 to obtain the corresponding hydroquinone concentration; the obtained hydroquinone concentration is the hydroquinone content in the water sample to be tested.

[0009] Preferably, in step 1, the number of hydroquinone reaction solutions is at least 4; the gradient concentration range of the hydroquinone reaction solution is 1.0-200.0 μmol / L; the concentration of the peroxodisulfate reaction solution is 10.0-100.0 mmol / L; the concentration of the sodium hydroxide reaction solution is 1.0-10.0 mmol / L;

[0010] Preferably, in step 2, the volume of the mixed solution is 20.0-200.0 μL;

[0011] Preferably, in step 4, the linear expression is monotonically increasing in the first quadrant. max When the value is determined, there is only one hydroquinone concentration value corresponding to it;

[0012] Preferably, in step 5, the content of hydroquinone in the water sample to be tested is within the detection range of the linear expression.

[0013] The beneficial effects brought about by the technical solution of the present invention are:

[0014] (1) The constructed chemiluminescence method is simple to operate, highly sensitive, and can be carried out in an aqueous solution environment.

[0015] (2) This chemiluminescence method does not rely on additional luminescent agents and catalysts. Hydroquinone plays the dual role of co-reactant and luminescent agent.

[0016] (3) This chemiluminescence method can achieve selective detection of hydroquinone. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The chemiluminescence curves of Example 1 and Comparative Examples 1 to 3 are shown;

[0018] Figure 2 The chemiluminescence intensity dotted line graph of Example 2 at different hydroquinone concentrations;

[0019] Figure 3 The chemiluminescence intensity dotted line graph of Example 3 at different sodium hydroxide concentrations. Implementation Method

[0020] In order to better understand the content of the present invention, the technical solution of the present invention is further described below through specific embodiments and drawings. However, these embodiments do not limit the scope of protection of the present invention. Example

[0021] Step 1, respectively preparing a 50 μmol / L hydroquinone reaction solution, a 50 mmol / L sodium persulfate reaction solution, and a 10 mmol / L sodium hydroxide reaction solution;

[0022] Step 2: Pipette 50 μL each of the sodium persulfate and sodium hydroxide reaction solutions prepared in step 1 and mix them;

[0023] Step 3. Take 100 μL of the hydroquinone reaction solution prepared in step 1 and quickly inject it into the mixed solution obtained in step 2 using a static injection device. A series of chemical reactions will occur at the moment of mixing: hydroquinone first reacts with sodium hydroxide to produce semiquinone free radicals; then, the semiquinone free radicals react with peroxydisulfate to produce sulfate free radicals; finally, the sulfate free radicals can oxidize hydroquinone to produce chemiluminescent substances, thereby producing chemiluminescence; the intensity of the generated chemiluminescence is detected and recorded by a chemiluminescence instrument.

[0024] Step 1, respectively preparing a 50 mmol / L sodium persulfate reaction solution and a 10 mmol / L sodium hydroxide reaction solution;

[0025] Step 2: Pipette 50 μL each of the sodium persulfate and sodium hydroxide reaction solutions prepared in step 1 and mix them;

[0026] Step 3. Draw 100 μL of ultrapure water and, using a static injection device, quickly inject 100 μL of hydroquinone solution into the mixed solution obtained in Step 2. A series of chemical reactions will occur at the moment of mixing: hydroquinone first reacts with sodium hydroxide to produce semiquinone free radicals; then, the semiquinone free radicals react with peroxydisulfate to produce sulfate free radicals; finally, the sulfate free radicals can oxidize hydroquinone to produce chemiluminescent substances, thereby producing chemiluminescence; the intensity of the generated chemiluminescence is detected and recorded by a chemiluminescence instrument.

[0027] Step 1, respectively preparing a 50 μmol / L hydroquinone reaction solution and a 10 mmol / L sodium hydroxide reaction solution;

[0028] Step 2: Pipette 50 μL each of the sodium hydroxide reaction solution prepared in step 1 and ultrapure water and mix them;

[0029] Step 3. Take 100 μL of the hydroquinone reaction solution prepared in step 1 and quickly inject 100 μL of the hydroquinone solution into the mixed solution obtained in step 2 using a static injection device. A series of chemical reactions will occur at the moment of mixing: hydroquinone first reacts with sodium hydroxide to produce semiquinone free radicals; then, the semiquinone free radicals react with peroxydisulfate to produce sulfate free radicals; finally, the sulfate free radicals can oxidize hydroquinone to produce chemiluminescent substances, thereby producing chemiluminescence; the intensity of the generated chemiluminescence is detected and recorded by a chemiluminescence instrument.

[0030] Step 1, respectively preparing a 50 μmol / L hydroquinone reaction solution and a 50 mmol / L sodium persulfate reaction solution;

[0031] Step 2: Pipette 50 μL of the sodium persulfate reaction solution prepared in step 1 and 50 μL of ultrapure water and mix them;

[0032] Step 3. Take 100 μL of the hydroquinone reaction solution prepared in step 1 and quickly inject 100 μL of the hydroquinone solution into the mixed solution obtained in step 2 using a static injection device. A series of chemical reactions will occur at the moment of mixing: hydroquinone first reacts with sodium hydroxide to produce semiquinone free radicals; then, the semiquinone free radicals react with peroxydisulfate to produce sulfate free radicals; finally, the sulfate free radicals can oxidize hydroquinone to produce chemiluminescent substances, thereby producing chemiluminescence; the intensity of the generated chemiluminescence is detected and recorded by a chemiluminescence instrument.

[0033] The chemiluminescence curves of Example 1 and Comparative Examples 1 to 3 are as follows: Figure 1As shown, when hydroquinone is added to a mixed solution of peroxodisulfate and sodium hydroxide, a strong chemiluminescent signal is instantly generated. Furthermore, comparative analysis shows that hydroquinone, peroxodisulfate, and an alkaline environment are the three essential conditions for chemiluminescence in this system. Example

[0034] Step 1. Prepare several gradient concentrations of (2, 4, 20, 50, 100, 150, 200 μmol / L) hydroquinone reaction solutions, 50 mmol / L sodium persulfate reaction solution, and 10.0 mmol / L sodium hydroxide reaction solution;

[0035] Step 2: Pipette 50 μL each of the sodium persulfate and sodium hydroxide reaction solutions prepared in step 1 and mix them;

[0036] Step 3: Using a static injection device, the multiple hydroquinone reaction solutions prepared in step 1 are mixed with the mixed solution obtained in step 2 in equal volumes in a reaction tank. A series of chemical reactions occur at the moment of mixing: hydroquinone first reacts with sodium hydroxide to produce semiquinone free radicals; then, the semiquinone free radicals react with peroxydisulfate to produce sulfate free radicals; finally, the sulfate free radicals oxidize the hydroquinone to produce chemiluminescent substances, thereby generating chemiluminescence; the intensity of the generated chemiluminescence is detected and recorded by a chemiluminescence instrument; the maximum chemiluminescence intensity is read and recorded as CL max ;

[0037] Step 4: Use the logarithm of hydroquinone concentration as the horizontal axis and CL as the horizontal axis in the graphing software. max The logarithm of the value is the vertical axis, and the logarithm of the hydroquinone concentration (1, 2, 10, 25, 50, 75, 100 μmol / L) in the solution when the chemical reaction occurs in step 3, the logarithm of the CL obtained in step 3 max The logarithm of the value is plotted as a scatter plot, CL max The relationship between the value and the concentration of hydroquinone satisfies the relationship: lg(CL max )=a×lg(hydroquinone concentration)+b, thus obtaining the description of CL max A linear expression is formed between the logarithm of the value and the logarithm of the hydroquinone concentration; wherein, the values ​​of constants a and b (a>0, b≥0) can be solved by inserting a quadratic polynomial curve on the scatter plot.

[0038] Figure 2 The chemiluminescence intensity dotted line graph of Example 2 at different hydroquinone concentrations. The results show that the logarithm of the hydroquinone concentration is linearly related to the logarithm of its chemiluminescence intensity: lg(CL max )=1.726×lg(hydroquinone concentration)+0.878, R 2(Correlation coefficient) > 0.998. According to the linear equation, when the signal-to-noise ratio is 3, the detection limit of hydroquinone is 0.52 μmol / L. Example

[0039] Step 1, respectively preparing a 50 μmol / L hydroquinone reaction solution, a 50 mmol / L sodium persulfate reaction solution, and different concentrations (0, 1.0, 2.0, 4.0, 6.0, 8.0, 10.0 mmol / L) of sodium hydroxide reaction solutions;

[0040] Step 2: 50 μL of the sodium persulfate reaction solution prepared in step 1 was taken and mixed with equal volumes of sodium hydroxide reaction solutions of different concentrations;

[0041] Step 3: Using a static injection device, the hydroquinone reaction solution prepared in step 1 is mixed with several mixed solutions obtained in step 2 in equal volumes in a reaction tank; a series of chemical reactions occur at the moment of mixing: hydroquinone first reacts with sodium hydroxide to produce semiquinone free radicals; then, the semiquinone free radicals react with peroxydisulfate to produce sulfate free radicals; finally, the sulfate free radicals can oxidize the hydroquinone to produce a chemiluminescent substance, thereby generating chemiluminescence; the intensity of the generated chemiluminescence is detected and recorded by a chemiluminescence instrument; the maximum chemiluminescence intensity is read and recorded as CL max ;

[0042] Step 4: Use the sodium hydroxide concentration as the horizontal axis and CL as the horizontal axis in the graphing software. max The value is the vertical axis, and the concentration of sodium hydroxide in the solution when the chemical reaction occurs in step 3 (0, 0.25, 0.5, 1.0, 1.25, 2.0, 2.5 mmol / L), the number of CL obtained in step 3 max Draw a scatter plot of the value and get CL max The relationship between the value and the concentration of sodium hydroxide.

[0043] Figure 3 The figure shows the chemiluminescence intensity under different sodium hydroxide conditions in Example 3. The results show that the chemiluminescence signal intensity increases with the increase of sodium hydroxide concentration, but there is a limit to the sodium hydroxide concentration. Excessive sodium hydroxide concentration will inhibit the chemiluminescence signal intensity to a certain extent. Example

[0044] Step 1: Use lake water to prepare different concentrations of hydroquinone reaction solutions (20, 100, 150, 200 μmol / L), 50 mmol / L sodium persulfate reaction solution, and 10.0 mmol / L sodium hydroxide reaction solution;

[0045] Step 2: Pipette 50 μL each of the sodium persulfate and sodium hydroxide reaction solutions prepared in step 1 and mix them;

[0046] Step 3: Using a static injection device, the multiple hydroquinone reaction solutions prepared in step 1 are mixed with the mixed solution obtained in step 2 in equal volumes in a reaction tank. A series of chemical reactions occur at the moment of mixing: hydroquinone first reacts with sodium hydroxide to produce semiquinone free radicals; then, the semiquinone free radicals react with peroxydisulfate to produce sulfate free radicals; finally, the sulfate free radicals oxidize the hydroquinone to produce chemiluminescent substances, thereby generating chemiluminescence; the intensity of the generated chemiluminescence is detected and recorded by a chemiluminescence instrument; the maximum chemiluminescence intensity is read and recorded as CL max ;

[0047] Step 4: The CL measured in step 3 max The value is brought into the linear expression (log (CL) obtained in Example 2 max )=1.726×lg(hydroquinone concentration)+0.878) to obtain the corresponding hydroquinone concentration; the obtained hydroquinone concentration is the measured hydroquinone content in the lake water; thus, the recovery rate can be calculated based on the actual hydroquinone concentration in the reaction solution (10, 50, 750, 1000 μmol / L) and the measured hydroquinone concentration.

[0048] Example 4 evaluated the detection reliability of the system of the present invention in actual water samples. The results are shown in Table 1. For different concentrations of hydroquinone, the sample recovery rate ranged from 95.2% to 97.3%. This data fully demonstrates that the recovery rate of the system is good and that this system is highly practical for detecting hydroquinone.

[0049] Table 1 Determination of hydroquinone concentration in lake water

[0050] Hydroquinone concentration (μmol / L) Detection of hydroquinone concentration (μmol / L) Recovery rate (%) 10 9.52 95.2 50 47.90 95.8 75 72.14 96.2 100 97.26 97.3

[0051] As can be seen from the above examples, the present invention provides a chemiluminescence method in which hydroquinone, when added dropwise to a mixed solution of peroxodisulfate and sodium hydroxide, produces chemiluminescence. The intensity of the chemiluminescence is positively correlated with the concentration of hydroquinone. The present invention can utilize chemiluminescence for the quantitative detection of hydroquinone.

[0052] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for detecting hydroquinone in water using chemiluminescence, characterized in that: The method comprises the following steps: Step 1, preparing several concentration gradients of hydroquinone reaction solutions; preparing peroxydisulfate and sodium hydroxide reaction solutions; wherein the concentration gradient of the hydroquinone reaction solution ranges from 1.0 to 200.0 μmol / L; the concentration of the peroxydisulfate reaction solution ranges from 10.0 to 100.0 mmol / L; and the concentration of the sodium hydroxide reaction solution ranges from 1.0 to 10.0 mmol / L; Step 2: Mix equal volumes of the peroxodisulfate reaction solution prepared in step 1 and the sodium hydroxide reaction solution; wherein the volume of the mixed solution is 20.0-200.0 μL; Step 3: Using a static injection device, a plurality of hydroquinone reaction solutions prepared in Step 1 are mixed with the mixed solution obtained in Step 2 in equal volumes in a reaction tank; a series of chemical reactions occur upon mixing: hydroquinone first reacts with sodium hydroxide to produce semiquinone free radicals; then, the semiquinone free radicals react with peroxydisulfate to produce sulfate free radicals; finally, the sulfate free radicals oxidize the hydroquinone to produce a chemiluminescent substance, thereby generating chemiluminescence; the intensity of the generated chemiluminescence is detected and recorded by a chemiluminescence instrument; and the maximum chemiluminescence intensity is read and recorded as CLmax; Step 4. Using a plotting software, draw a scatter plot using the logarithm of the hydroquinone concentration as the abscissa and the logarithm of the CLmax value as the ordinate, using the logarithm of the hydroquinone concentration in the solution at the time of the chemical reaction in Step 3 and the logarithm of the several CLmax values ​​obtained in Step 3. Subsequently, perform a linear fit on the scatter plot to obtain a standard curve. The equation of the standard curve is: lg(CLmax)=a×lg(hydroquinone concentration)+b; where a and b are constants, a>0, b≥0; Step 5: Determine the corresponding CLmax value of the water sample to be tested according to step 3; substitute the obtained CLmax value into the standard curve in step 4 to obtain the corresponding hydroquinone concentration; the obtained hydroquinone concentration is the hydroquinone content in the water sample to be tested.

2. The method for detecting hydroquinone in water using chemiluminescence according to claim 1, wherein: In step 1, at least four hydroquinone reaction solutions with different concentration gradients are prepared.

3. The method for detecting hydroquinone in water using chemiluminescence according to claim 1, wherein: In step 4, the equation of the standard curve is monotonically increasing in the first quadrant. When the CLmax value is determined, there is only one hydroquinone concentration value corresponding to it.

4. The method for detecting hydroquinone in water using chemiluminescence according to claim 1, wherein: In step 5, the hydroquinone content in the water sample to be tested is within the detection range of the linear expression.

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