A sensitive detection of tert-butyl hydroquinone modified glassy carbon electrode, preparation method and application

Abstract

The present application relates to the technical field of electrochemical analysis detection, and particularly relates to a modified glassy carbon electrode for sensitive detection of tert-butyl hydroquinone, a preparation method and application, which has a high specific surface area and catalytic activity, and has good conductivity, and can realize sensitive detection of tert-butyl hydroquinone, the modified glassy carbon electrode comprises a glassy carbon electrode and a composite coating, the composite coating is wrapped on the surface of the glassy carbon electrode, and the composite coating is composed of graphene oxide and a Ti-based MOF derivative; the preparation method comprises the following steps: (1) preparation of MIL-125 (Ti); (2) preparation of TiO2 / NC; (3) preparation of 15% GO@TiO2 / NC; (4) preparation of a 15% GO@TiO2 / NC composite material dispersion liquid; (5) preparation of a modified electrode; and the application comprises the following steps: S1, establishing a concentration-electrochemical response signal relationship; S2, determining the concentration of a to-be-detected substance.

Description

Technical Field

[0001] This invention relates to the technical field of electrochemical analysis and detection, and in particular to a sensitive glassy carbon electrode for detecting tert-butylhydroquinone, its preparation method, and its application. Background Technology

[0002] tert-Butylhydroquinone is a key synthetic antioxidant in the food industry, effectively blocking oil oxidation and significantly extending the shelf life of food. Its unique antioxidant properties make it widely used in fried foods, instant noodles, and other oily foods. However, excessive intake may pose potential risks to human health. Therefore, establishing detection methods for tert-Butylhydroquinone is of great value in ensuring food safety, regulating the use of food additives, and protecting consumer health, while also providing scientific evidence for regulatory authorities.

[0003] Currently, the detection of the food additive tert-butylhydroquinone mainly relies on traditional methods such as gas chromatography, liquid chromatography, and fluorescence analysis. However, these techniques generally suffer from limitations such as cumbersome pretreatment and complex operation. In contrast, electrochemical analysis methods have shown great potential due to their advantages of rapid response, high precision, and good selectivity; however, the detection performance of bare electrodes remains insufficient. In recent years, chemically modified electrode technology, especially composite modified electrodes, has been widely used in analytical detection due to its high active site density and strong signal response. Notably, research on drop-coated modified electrodes based on graphene oxide composite Ti-based MOF derivative materials for the detection of tert-butylhydroquinone has not yet been reported. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a modified glassy carbon electrode with high specific surface area and catalytic activity, as well as good conductivity, which enables sensitive determination of tert-butylhydroquinone, along with its preparation method and applications.

[0005] The present invention provides a sensitive detection method for tert-butylhydroquinone modified glassy carbon electrode, comprising a glassy carbon electrode and a composite coating, wherein the composite coating is coated on the surface of the glassy carbon electrode and is composed of graphene oxide and Ti-based MOF derivatives.

[0006] The present invention provides a method for preparing a glassy carbon electrode modified with tert-butylhydroquinone for sensitive detection, comprising the following steps:

[0007] (1) Preparation of MIL-125(Ti): 2-aminoterephthalic acid and terephthalic acid were completely dissolved in N,N-dimethylformamide solution, and methanol was added. Tetraisopropyl titanate was added to the solution, and the mixture was stirred until a yellow precipitate appeared. After sonication, the mixture was sealed in a reaction vessel. After the reaction vessel cooled to room temperature, it was removed, centrifuged, and washed three times each with DMF and methanol. Then it was dried in a vacuum drying oven to obtain yellow MOF powder.

[0008] (2) Preparation of TiO2 / NC: The obtained MIL-125 (Ti) was completely carbonized in a tube furnace under N2 atmosphere. A black powder of TiO2 / NC composite material was obtained;

[0009] (3) Preparation of 15% GO@TiO2 / NC: A certain amount of monolayer GO was dissolved in DMF and ultrasonically treated. TiO2 / NC and terephthalic acid were weighed and mixed with the solution, and stirred at room temperature. Then, the solution was transferred to a reaction vessel for reaction. After the reaction vessel cooled to room temperature, the solution was removed, washed three times each with DMF and deionized water, and centrifuged. Finally, the obtained 15% GO@TiO2 / NC was dried in a vacuum oven to obtain a black powder;

[0010] (4) Preparation of 15% GO@TiO2 / NC dispersion: Disperse 15% GO@TiO2 / NC in N,N-dimethylformamide and sonicate it to obtain 15% GO@TiO2 / NC dispersion;

[0011] (5) Fabrication of modified electrode: The composite material dispersion from step (4) is drop-coated onto the polished and cleaned glassy carbon electrode surface using a drop-coating method. After drying, a 15% GO@TiO2 / NC composite modified electrode is obtained.

[0012] Further, in step (1), 0.5435 g (3 mmol) of 2-aminoterephthalic acid and 0.4984 g (3 mmol) of terephthalic acid were completely dissolved in 20 ml of N,N-dimethylformamide solution, and 2.2 ml of methanol was added. 0.9 ml of tetraisopropyl titanate was added to the solution, and the mixture was stirred for 30 min until a yellow precipitate appeared. The mixture was then sonicated for 30 s and sealed in a reaction vessel, and reacted at 150 °C for 24 h. After the reaction vessel cooled to room temperature, the solution was removed, washed three times each with DMF and methanol, centrifuged (12000 rpm), and then placed in a vacuum drying oven at 100 °C for 12 h to obtain yellow MOF powder.

[0013] Furthermore, in step (2), the MIL-125 (Ti) obtained in step (1) is carbonized in a tube furnace at a heating rate of 5°C / min under a N2 atmosphere at 1000°C for 5 hours to completely carbonize the material. A black powder of TiO2 / NC composite material is obtained.

[0014] Further, in step (3), a certain amount of monolayer GO was dissolved in 15 ml of DMF and sonicated for 30 min. 0.15 g of TiO2 / NC and 0.1 g of terephthalic acid were weighed and mixed with the solution, and stirred at room temperature for 68 h (300 r / min). Then, the solution was transferred to a reaction vessel and reacted at 120 °C for 4 h. After the reaction vessel cooled to room temperature, the solution was removed, centrifuged, and washed three times each with DMF and deionized water. Finally, the obtained 15% GO@TiO2 / NC was dried in a vacuum oven at 80 °C for 24 h to obtain a black powder. Other samples x% GO@TiO2 / NC (x% represents the weight percentage of GO and TiO2 / NC) were synthesized using a similar method to obtain GO@TiO2 / NC with different proportions.

[0015] Further, 2 mg of 15% GO@TiO2 / NC was weighed and dispersed in 2 ml of N,N-dimethylformamide. The mixture was sonicated for 3 min to obtain a 15% GO@TiO2 / NC dispersion with a concentration of 1 mg / ml and uniform dispersion. In step (4), N,N-dimethylformamide was selected as the solvent. N,N-dimethylformamide is an excellent organic solvent and is often used to disperse nanomaterials. N,N-dimethylformamide has a good affinity with graphene oxide, which can make the 15% GO@TiO2 / NC composite material dispersed quickly and uniformly in it. Moreover, N,N-dimethylformamide is a polar inert solvent and will not react with graphene oxide or Ti-based MOF derivatives, thus avoiding the generation of side reactions.

[0016] Furthermore, in step (5), the amount of 15% GO@TiO2 / NC composite material dispersion is 10 μL. The amount of composite material on the electrode affects the electrochemical reduction response current of the analyte. If the amount of composite material is too small, the response current will be too small. As the amount of composite material is increased, the electrochemical response current of the analyte gradually increases.

[0017] The present invention provides an application of a sensitive detection electrode for tert-butylhydroquinone modified glassy carbon, comprising the following steps:

[0018] S1. Establish the concentration-electrochemical response signal relationship: Prepare a series of standard solutions with concentration gradients, and place them in the working electrode, auxiliary electrode and reference electrode respectively. Detect the electrochemical response signal on the working electrode, and establish the concentration-electrochemical response signal relationship based on the correspondence between the electrochemical response signal and the concentration.

[0019] S2. Determine the concentration of the analyte: Place the working electrode, auxiliary electrode, and reference electrode into the analyte solution, detect the electrochemical response signal on the working electrode, and calculate the concentration of the analyte based on the concentration-electrochemical response signal relationship obtained in S1.

[0020] Furthermore, the working electrode is a 15% GO@TiO2 / NC composite modified electrode.

[0021] Furthermore, the analyte solution in S2 is a tert-butylhydroquinone solution obtained by dissolving tert-butylhydroquinone in a phosphate buffer solution and bringing the volume to a constant volume. When electricity is applied, tert-butylhydroquinone undergoes a redox reaction at the working electrode, generating a corresponding current.

[0022] Further, in step S2, 0.0083 g of tert-butylhydroquinone is weighed and dissolved in a 50 ml beaker, stirred with a glass rod until completely dissolved, and then transferred to a 50 ml volumetric flask to obtain a tert-butylhydroquinone concentration of 1*10. -3 mol / L.

[0023] Furthermore, the phosphate buffer solution in S2 is a phosphate buffer solution obtained by mixing 0.1 mol / L Na2HPO4 and 0.1 mol / L NaH2PO4 solutions until the pH reaches 7.0.

[0024] Furthermore, the method for detecting the electrochemical response signal on the working electrode in S2 is to use cyclic voltammetry to detect the reduction peak current on the working electrode. When the analyte undergoes a redox reaction on the electrode, there is a unique reduction peak current that corresponds one-to-one with the concentration of the analyte during the cyclic voltammetry detection process. Therefore, a definite concentration-electrochemical response signal relationship can be established.

[0025] Graphene oxide, due to its unique spatial structure, geometric morphology, electronic and chemical properties, can promote electron transfer when adsorbed on the electrode surface, and is therefore often used as a material to modify glassy carbon electrodes. In addition, Ti-based MOF derivatives, as metal-organic framework materials, have the advantages of high specific surface area and easily tunable pores. This invention adopts a novel electrode preparation method, in which 15% GO@TiO2 / NC composite material is drop-coated onto a glassy carbon electrode. By utilizing the synergistic effect of the two, the electrochemical detection performance of glassy carbon electrodes for tert-butylhydroquinone is enhanced.

[0026] The glassy carbon electrode used in this invention has good conductivity, high chemical stability, and a small coefficient of thermal expansion. It is also hard, has good airtightness, and a wide potential range, making it very suitable as a base electrode. However, the bare electrode's detection performance for tert-butylhydroquinone is still insufficient. Therefore, suitable modification materials need to be developed to provide a sensitive electrochemical response for the detection of tert-butylhydroquinone. Graphene oxide, due to its high specific surface area, porous structure, and high graphitization degree, is beneficial for the exposure of catalytic active sites, electrocatalysis-related substance transport, and electron transfer, thus showing broad application prospects in the sensing field. Studies have shown that metal-organic frameworks have attracted attention due to their wide applications in gas storage, separation, biomedicine, and heterogeneous catalysis. TiO2 / NC can be used as an electrode modification material for the detection of tert-butylhydroquinone. Ti-based MOF derivatives and graphene oxide can synergistically interact, exhibiting better catalytic performance. Therefore, a 15% GO@TiO2 / NC composite is used (…). Figure 1 , Figure 2 Modifying glassy carbon electrodes with α-phosphorus compounds can enhance their catalytic performance, stability, and conductivity.

[0027] In the preparation method provided by this invention, graphene oxide has a high specific surface area, which increases the specific surface area of ​​the electrode, thereby increasing the enrichment of analytes on the electrode surface. At the same time, it retains the stability of Ti-based MOF derivatives, ensuring the catalytic performance of the electrode and improving its conductivity. In addition, graphene oxide and Ti-based MOF derivatives can have a synergistic effect, further improving the conductivity of the electrode.

[0028] Electrochemical detection was performed using the 15% GO@TiO2 / NC composite modified electrode prepared according to this invention. Under energized conditions, tert-butylhydroquinone underwent an electrochemical redox reaction on the 15% GO@TiO2 / NC composite modified electrode, generating an electrochemical signal. The electrochemical response signal has a one-to-one correspondence with the analyte concentration, thus enabling accurate detection of the analyte. Simultaneously, the catalytically active sites of the modified material are fully exposed, exhibiting excellent catalytic activity and catalyzing the electrode reaction. The graphene oxide within it possesses a rich porous structure, enabling rapid transfer of the analyte to the surface of the 15% GO@TiO2 / NC composite modified electrode, forming an analyte-enriched region, thereby accelerating the electron transfer rate and improving the electrode reaction rate. Attached Figure Description

[0029] Figure 1 SEM images of 15% GO@TiO2 / NC composite material;

[0030] Figure 2 TEM of 15% GO@TiO2 / NC composite material;

[0031] Figure 3 Electrochemical detection results for the electrode modified with 15% GO@TiO2 / NC composite material: concentration-reduction peak current standard curve between reduction peak current and tert-butylhydroquinone concentration;

[0032] Figure 4A Comparison of cyclic voltammetry for tert-butylhydroquinone using electrodes modified with different materials;

[0033] Figure 4B Cyclic voltammetry comparison of electrodes modified with different proportions of GO@TiO2 / NC composite material for tert-butylhydroquinone;

[0034] Figure 5 Comparison of cyclic voltammetry of modified electrodes for tert-butylhydroquinone under different pH conditions;

[0035] Figure 6 The effect of different interfering substances on tert-butylhydroquinone (it curve) is shown in the figure: When tert-butylhydroquinone is added to phosphate buffer, the current has a significant response, while other interfering substances have little effect on it. Detailed Implementation

[0036] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention. Example 1

[0037] Electrochemical response comparison experiment of electrode modified with 15% GO@TiO2 / NC composite

[0038] Take a glassy carbon electrode, polish it with 0.3μm Al2O3 slurry on a polishing cloth for 5 minutes, clean it with ultrapure water, and then sonicate it with HNO3 (1:1), ethanol (1:1) and double-distilled water for 30 seconds in sequence. After rinsing it with ultrapure water, dry it under an infrared lamp.

[0039] Weigh out 2 mg of 15% GO@TiO2 / NC, 2 mg of GO, 2 mg of TiO2 / NC, 2 mg of MIL-125 (Ti), 2 mg of 15% GO@MIL-125 (Ti), 2 mg of 5% GO@TiO2 / NC, 2 mg of 10% GO@TiO2 / NC, 2 mg of 20% GO@TiO2 / NC, and 2 mg of 25% GO@TiO2 / NC respectively, and disperse them in 2 mL of N,N-dimethylformamide. Sonicate the solutions for 3 min to obtain a uniform dispersion with a concentration of 1 mg / mL.

[0040] (3) Take 10 μL of 15% GO@TiO2 / NC dispersion (concentration of 1 mg / ml) and drop it onto the bare electrode after polishing and cleaning. After the electrode surface is completely dried, the modified electrode 6 with 15% GO@TiO2 / NC composite is obtained.

[0041] As a comparative experiment, the unmodified bare electrode was labeled as electrode 1. Dispersions of 10 μL each of GO, TiO2 / NC, MIL-125(Ti), 15% GO@MIL-125(Ti), 25% GO@TiO2 / NC, 10% GO@TiO2 / NC, 20% GO@TiO2 / NC, and 5% GO@TiO2 / NC were drop-coated onto the surface of a glassy carbon electrode and dried under an infrared lamp to obtain modified electrodes, labeled as modified electrodes 2, 3, 4, 5, 7, 8, 9, and 10. Using a saturated calomel electrode as the reference electrode and a platinum electrode as the control electrode, electrodes 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 were used as working electrodes and connected to a CHI660E electrochemical workstation. Figure 4A and Figure 4B It can be seen that the modified electrode 6, i.e., the electrode modified with 15% GO@TiO2 / NC composite, has a significant current signal response and the best effect. Example 2

[0042] Effect of pH on the concentration of tert-butylhydroquinone in samples detected by a 15% GO@TiO2 / NC composite modified electrode

[0043] S1. Prepare a series of tert-butylhydroquinone standard concentration solutions with pH=5-9;

[0044] S2. The working electrode, auxiliary electrode, and reference electrode were placed separately, and the electrochemical response signal on the working electrode was detected to obtain the CV curves of tert-butylhydroquinone standard solutions at different concentrations and pH conditions on modified electrode 5. Based on... Figure 5 It can be seen that the composite-modified electrode exhibits the most significant current signal response and the best effect at pH=7. Example 3

[0045] A method for detecting the concentration of tert-butylhydroquinone in samples using a 15% GO@TiO2 / NC composite modified electrode.

[0046] S1. Prepare a series of standard solutions with varying concentrations, and place them on the working electrode, auxiliary electrode, and reference electrode, respectively. Detect the electrochemical response signal on the working electrode to obtain the DPV curves of different concentrations of tert-butylhydroquinone standard solutions on modified electrode 5. Establish a concentration-electrochemical response signal relationship based on the correspondence between the electrochemical response signal and the concentration.

[0047] S2. Place the working electrode, auxiliary electrode, and reference electrode into the analyte solution, detect the electrochemical response signal on the working electrode, and obtain the corresponding concentration-reduction peak current standard curve to obtain the corresponding tert-butylhydroquinone concentration.

[0048] Figure 3 The results show that the 15% GO@TiO2 / NC composite modified electrode of the present invention can effectively and accurately detect tert-butylhydroquinone and has good applicability. Example 4

[0049] Effect of interfering substances on tert-butylhydroquinone

[0050] Experimental study on the response of modified electrode 6 to current and a range of possible disturbances.

[0051] The addition of 10 μM tert-butylhydroquinone resulted in a significant current response. Interference from compounds such as MgCl2, NaCl, CaCl2, L-cysteine, glycine, glucose, luteolin, quercetin, and catechol was minimal; no current response was observed after the addition of these interfering substances. These results indicate that modified electrode 6 exhibits good selectivity. Figure 6 ).

[0052] This invention is not limited to the above-described embodiments. If any modifications or variations to this invention do not depart from the spirit and scope of this invention, and if such modifications and variations fall within the scope of the claims and equivalent technologies of this invention, then this invention also intends to include such modifications and variations.

Claims

1. A method for preparing a glassy carbon electrode modified with tert-butylhydroquinone for detection, characterized in that, Includes the following steps: (1) Preparation of MIL-125(Ti): 2-aminoterephthalic acid and terephthalic acid were completely dissolved in N,N-dimethylformamide solution and methanol was added. Tetraisopropyl titanate was added to the solution and stirred until a yellow precipitate appeared. After ultrasonic treatment, it was sealed in a reaction vessel. After the reaction vessel was cooled to room temperature, the solution was taken out and washed with DMF and methanol three times each. After centrifugation, it was placed in a vacuum drying oven to dry and obtain yellow MOF powder. (2) Preparation of TiO2 / NC: The obtained MIL-125 (Ti) was completely carbonized in a tube furnace under N2 atmosphere to obtain a black powder of TiO2 / NC composite material; (3) Preparation of 15% GO@TiO2 / NC: A certain amount of monolayer GO was dissolved in DMF and ultrasonically treated. TiO2 / NC and terephthalic acid were weighed and mixed with the solution. The mixture was stirred at room temperature. The solution was then transferred to a reaction vessel for reaction. After the reaction vessel cooled to room temperature, the solution was removed and washed three times each with DMF and deionized water. The obtained 15% GO@TiO2 / NC was dried in a vacuum oven to obtain a black powder. 15% represents the weight percentage of GO and TiO2 / NC. (4) Preparation of 15% GO@TiO2 / NC dispersion: Disperse 15% GO@TiO2 / NC in N,N-dimethylformamide and sonicate it to obtain 15% GO@TiO2 / NC dispersion; (5) Fabrication of modified electrode: The composite material dispersion from step (4) is drop-coated onto the polished and cleaned glassy carbon electrode surface using a drop-coating method. After drying, a 15% GO@TiO2 / NC composite modified electrode is obtained.

2. The method for preparing a glassy carbon electrode modified with tert-butylhydroquinone as described in claim 1, characterized in that, In step (1), the mixed solution is ultrasonically treated for 30 seconds, then transferred to a reaction vessel and placed in an oven at 150°C for 24 hours. After centrifugation, it is placed in a vacuum drying oven at 100°C for 12 hours.

3. The method for preparing a glassy carbon electrode modified with tert-butylhydroquinone as described in claim 1, characterized in that, In step (2), the MIL-125 (Ti) powder is carbonized at 1000°C for 5 hours under N2 atmosphere.

4. The method for preparing a glassy carbon electrode modified with tert-butylhydroquinone as described in claim 1, characterized in that, In step (5), the amount of 15% GO@TiO2 / NC dispersion is 10 μL.

5. An application of a glassy carbon electrode for detecting tert-butylhydroquinone, characterized in that, Includes the following steps: S1. Establish the concentration-electrochemical response signal relationship: Prepare a series of standard solutions with concentration gradients, and place them in the working electrode, auxiliary electrode and reference electrode respectively. Detect the electrochemical response signal on the working electrode, and establish the concentration-electrochemical response signal relationship based on the correspondence between the electrochemical response signal and the concentration. S2. Determine the concentration of the analyte: Place the working electrode, auxiliary electrode, and reference electrode into the analyte solution, detect the electrochemical response signal on the working electrode, and calculate the concentration of the analyte based on the concentration-electrochemical response signal relationship obtained in S1. The working electrode is a 15% GO@TiO2 / NC composite modified electrode prepared by the preparation method according to any one of claims 1-4; the analyte solution in S2 is a tert-butylhydroquinone solution.

6. The application of the glassy carbon electrode for detecting tert-butylhydroquinone modified as described in claim 5, characterized in that, The method for detecting the electrochemical response signal on the working electrode in S2 is to use cyclic voltammetry to detect the reduction peak current on the working electrode.

Images