Electrochemical Detection Method of Menthol Based on Its Competitive Entry into β-Cyclodextrin with Ferrocene

Abstract

The present invention discloses an electrochemical detection method for menthol based on its competitive entry into β-cyclodextrin with ferrocene. Specifically, it includes the following steps: 1) synthesize silica microspheres with bromine groups; 2) bind ferrocene to the silica microspheres; 3) detect different concentrations of menthol using the prepared material based on an electrochemical method. By utilizing the competitive reaction of menthol and ferrocene entering cyclodextrin and the electrochemical activity of ferrocene, the detection range of menthol is improved and a lower detection limit is achieved. The innovation of this method lies in that there has been no use of an electrochemical method to detect menthol before. This method does not require the aid of precise and expensive experimental equipment and does not have a strict and complex experimental treatment process. The operation method of the present invention is convenient, simple, and highly sensitive.

Description

Technical Field

[0001] The present invention belongs to the field of biotechnology, and particularly relates to an electrochemical detection method of menthol based on its competition with ferrocene for entering β-cyclodextrin. Background Art

[0002] Menthol is a terpene organic compound with the chemical formula C 10 H 20 O. Menthol generally has two isomers (D-type and L-type), and natural menthol is mainly the left-handed isomer (L-menthol). Menthol can be used as a flavoring agent in cigarettes, toothpaste, candies, etc. In medicine, it is used as a stimulant and has a cooling and antipruritic effect. During the production process of cigarettes, adding menthol can relieve the throat irritation caused by cigarette burning and smoke. In addition, menthol also has the effect of dilating the bronchus after being lit, and then can reduce the choking feeling brought by cigarette burning.

[0003] As a common additive, the detection of menthol content has attracted people's attention. The current detection methods mainly include mass spectrometry, quartz crystal microbalance, etc. The sample preparation is complex and the requirements for machine operation are high. At the same time, the obtained detection range is also small, and the sensitivity is not sufficient to meet the requirements.

[0004] And menthol is difficult to detect due to the lack of main functional groups. Therefore, there is an urgent need for a simple and highly sensitive electrochemical detection method specifically for menthol that can overcome the above problems. Summary of the Invention

[0005] Object of the Invention: The technical problem to be solved by the present invention is to indirectly determine the concentration of menthol by using the electrochemical activity of ferrocene and its competitive effect with menthol for entering cyclodextrin, overcoming the problem of difficult detection of menthol due to the lack of main functional groups, and thus proposing an electrochemical detection method of menthol based on its competition with ferrocene for entering cyclodextrin, which is simple in method and high in detection sensitivity.

[0006] Technical Solution: To solve the above technical problem, the present invention provides an electrochemical detection method of menthol based on its competition with ferrocene for entering β-cyclodextrin, including the following steps:

[0007] 1) React tetraethyl orthosilicate, (3-bromopropyl) trimethoxysilane and triethylamine in a mixed solution of water and ethanol to obtain a precipitate, and then dry the precipitate to obtain silica microspheres with bromine groups;

[0008] 2) React the silica microspheres with N,N-dimethylaminomethyl ferrocene in dichloromethane solution, wash the precipitate with absolute ethanol, and then dry the precipitate to obtain silica microspheres with ferrocene groups;

[0009] 3) Dissolve the obtained ferrocene-group-containing silica microspheres in water, sonicate, then mix with an aqueous β-cyclodextrin solution, let stand at room temperature and then centrifuge. Dissolve the obtained precipitate in water to prepare an aqueous SiO2-Fc-CD solution;

[0010] 4) Modify the prepared aqueous SiO2-Fc-CD solution on the surface of a glassy carbon electrode to obtain an electrochemical signal. Drop different concentrations of menthol solutions to obtain different electrochemical signal intensities, and establish a relationship curve between the electrochemical signal intensity and the concentration of the menthol solution;

[0011] 5) Modify the prepared aqueous SiO2-Fc-CD solution on the surface of a glassy carbon electrode, drop the target menthol solution to be measured, and obtain the concentration of the target menthol to be measured according to the electrochemical signal intensity obtained from the relationship curve in step 4).

[0012] Among them, in step 1), the mass ratio of tetraethyl orthosilicate to (3-bromopropyl) trimethoxysilane is 5:2, and the volume ratio of triethylamine, water and ethanol is 0.2:15:15.

[0013] Among them, in step 2), the mass-volume ratio of N,N-dimethylaminomethylferrocene to dichloromethane solution is 35:30 mg / mL.

[0014] Among them, in step 3), the concentration of the aqueous β-cyclodextrin solution is 200 mg / mL, and the concentration of the aqueous SiO2-Fc-CD solution is 2 mg / mL.

[0015] Among them, in step 4), the concentration of menthol is 10 2 -10 7 nM.

[0016] Among them, in steps 4) and 5), the pH of the reaction solution is 7.

[0017] Application of the electrochemical detection and analysis method of menthol based on competing with ferrocene to enter β-cyclodextrin described in the content of the present invention in the field of detection of foods or other products containing menthol.

[0018] Among them, the concentration of menthol is 10 2 -10 7 nM, and the electrolyte used for the electrochemical detection is a 0.1 M KCl solution.

[0019] Among them, the food includes white sugar, and other products containing menthol include essential oils.

[0020] The specific steps of the electrochemical detection and analysis method are as follows: 1) React tetraethyl orthosilicate, (3-bromopropyl)trimethoxysilane, and triethylamine in a mixed solution of water and ethanol for 12 hours at a reaction temperature of 80 °C, and then dry the precipitate at 60 °C for 24 hours to obtain bromine-group-containing silica microspheres;

[0021] 2) React the silica microspheres with N,N-dimethylaminomethylferrocene in dichloromethane solution for 24 hours at a reaction temperature of 85 °C, wash the precipitate three times with absolute ethanol, and then dry the precipitate at 60 °C for 24 hours;

[0022] 3) Dissolve the obtained ferrocene-group-containing silica microspheres in water and ultrasonicate. Then mix with an aqueous β-cyclodextrin solution, let it stand at room temperature for 1 hour and then centrifuge, and dry the obtained precipitate at 60 °C to prepare the material;

[0023] 4) Modify the prepared material SiO2-Fc-CD on the surface of a glassy carbon electrode to obtain a lower electrochemical signal, drop different concentrations of menthol solution, and obtain different electrochemical signal intensities.

[0024] The present invention also includes an electrochemical material, which is obtained by modifying the synthesized SiO2-Fc-CD on a glassy carbon electrode.

[0025] Among them, the specific application includes: dissolving the detection target molecule menthol in a certain amount of aqueous solution to prepare a series of menthol solutions with different concentrations, using the prepared electrochemical material to detect menthol by an electrochemical method with a three-electrode system to obtain a corresponding concentration gradient change curve. Use a potentiostat with differential pulse voltammetry to detect the electrochemical signal intensity of each concentration of the target substance, and different electrochemical signals corresponding to different concentrations can be obtained according to different signal intensities, and a change curve is prepared, so that the concentration of the target substance can be reflected by the electrochemical signal intensity on the curve. After the detection is completed, polish the working electrode with aluminum oxide powder. Each concentration of the target molecule is detected in parallel 3 times to reduce the influence of errors.

[0026] Among them, the concentration of the target molecule menthol is 10 2 -10 7 nM; the three-electrode system uses a platinum electrode as the counter electrode, a silver-silver chloride electrode as the reference electrode, and a glassy carbon electrode as the working electrode, and the electrolyte used for the electrochemical detection is a 0.1 M KCl solution.

[0027] Advantages: Compared with the prior art, the present invention has the following advantages: The principle of the present invention is simple, the method used is simple, the experimental period is short, no large-scale instruments are required, the experimental cost is low, the detection is relatively sensitive, and the target substance can be detected more conveniently and quickly under the same conditions. The present invention relies on the competitive effect of ferrocene and menthol entering cyclodextrin, and uses an electrochemical method to detect the change in the electrochemical signal of ferrocene to indirectly detect the concentration of menthol. By using the electrochemical signal response detected by the electrochemical method, the detection of target menthol at a lower concentration can be achieved. Compared with other detection methods for menthol, differential pulse voltammetry is used for the first time to detect menthol, with a wider detection concentration range, a lower detection limit, and higher sensitivity. The present invention does not require expensive and precise instruments for detection, and the detection method is simple and easy to perform, greatly reducing the detection cost of menthol, and having the advantages of high sensitivity and short detection time. Description of the Drawings

[0028] Figure 1 Shows a flowchart of the construction of an electrochemical detection method for menthol based on its competitive entry into cyclodextrin with ferrocene, Figure 1 A shows a schematic diagram of the synthesis of SiO2-Fc microspheres, Figure 1 B shows a process diagram for detecting target molecules based on an electrochemical method;

[0029] Figure 2 A shows the feasibility verification of differential pulse voltammetry for the electrochemical detection method of menthol based on its competitive entry into cyclodextrin with ferrocene, and the experimental purpose is achieved according to the change in the electrical signal, Figure 2 B shows the feasibility verification of cyclic voltammetry for this method;

[0030] Figure 3 Shows a TEM image of the synthesized SiO2-Fc material, and the inset is a particle size diagram of the material;

[0031] Figure 4 Shows the zeta potential diagram of the synthesized material and intermediate;

[0032] Figure 5 Shows the FT-IR diagram of the synthesized material;

[0033] Figure 6 Shows the thermogravimetric analysis diagram of the material, with a heating range of 50 - 600 °C;

[0034] Figure 7 Shows the change in electrochemical signal intensity under different conditions; Figure 7 A shows the change in electrochemical signal intensity with pH from 6.5 - 8.5, Figure 7 B shows the change in electrochemical signal intensity with the material concentration from 1 - 5 mg / mL;

[0035] Figure 8Shows the electrochemical detection method of menthol based on its competition with ferrocene for entry into cyclodextrin, with the target molecule being 10. 2 -10 7 The change in the electrochemical signal intensity at -10 nM and the fitted linear curve.

[0036] Figure 9 Shows the structural formulas of the substances used in the selectivity experiment. 1 - Menthol acetate; 2 - Mentholamide; 3 - Glucose; 4 - Fructose; 5 - Glutamic acid; 6 - Menthol.

[0037] Figure 10 Shows the selectivity of the electrochemical detection method of menthol based on its competition with ferrocene for entry into cyclodextrin. 1 - Menthol acetate; 2 - Mentholamide; 3 - Glucose; 4 - Fructose; 5 - Glutamic acid; 6 - Menthol. Detailed implementation manners

[0038] The present invention will be further described below through specific examples and drawings. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several variations and improvements can also be made, which should also be regarded as belonging to the protection scope of the present invention.

[0039] Reagents and instruments used in this experiment:

[0040] Triethylamine was purchased from Sinopharm Chemical Reagent Co., Ltd., China. Tetraethyl orthosilicate (TEOS) was purchased from Sigma - Aldrich. N,N - Dimethylaminomethylferrocene was purchased from Macklin Reagent (China, Shanghai). (3 - Bromopropyl)trimethoxysilane was purchased from Shanghai Yuanye Bio - Technology Co., Ltd. Dichloromethane (DCM), β - cyclodextrin (β - CD), menthol (Men), N - ethyl - p - toluene - 3 - carboxamide (WS - 3), (1R)-(-)-menthol acetate were purchased from Aladdin (China, Shanghai). All reagents were of analytical grade and did not require further treatment. All experimental water used was ultrapure water (with an impedance of 18.2 MΩ·cm at 25 °C).

[0041] The time - current curve was obtained by measuring the change in the current signal over time using an electrochemical workstation (CHI 660C, Shanghai Chenhua, China). The solution was mixed using an oscillator.

[0042] Example 1 Synthesis of the electrochemical material SiO2 - Fc - CD

[0043] First, weigh 200 mg of tetraethyl orthosilicate and 80 mg of (3-bromopropyl)trimethoxysilane and place them in a round-bottom flask. Add 0.2 mL of triethylamine, and the reaction solvent is a mixed solution of 15 mL of water and 15 mL of ethanol. Heat it in an oil bath to 80 °C and stir the reaction for 12 hours with a magnetic stirrer. Wash the obtained white precipitate three times with absolute ethanol, and then dry it at 60 °C for 24 hours to obtain silica microspheres with bromine groups (SiO2-Br material). Next, weigh 100 mg of silica microspheres and 35 mg of N,N-dimethylaminomethylferrocene and place them in a round-bottom flask. The reaction solvent is 30 mL of dichloromethane. Heat it in an oil bath to 85 °C and stir the reaction for 24 hours. Connect the amino group in N,N-dimethylaminomethylferrocene to the bromine group on the silica microspheres, that is, introduce ferrocene onto the silica microspheres. After reacting for 24 hours, a light orange precipitate is obtained. Wash it three times with absolute ethanol, and then dry the precipitate at 60 °C for 24 hours to obtain SiO2-Fc. Finally, weigh 100 mg of the obtained SiO2-Fc and 200 mg of β-cyclodextrin and dissolve them together in ultrapure water. Let the mixture stand at room temperature for 1 hour, then centrifuge. Wash the precipitate three times with ultrapure water to remove free β-cyclodextrin, and then dry the precipitate at 60 °C for 24 hours to obtain SiO2-Fc-CD. The synthesized material is stored under closed conditions at room temperature. Figure 1 The synthesis process of the material is shown. When used later, weigh 2 mg of SiO2-Fc-CD and disperse it in 1 mL of water by ultrasonic to obtain an aqueous solution of SiO2-Fc-CD.

[0044] Example 2 Detection application of SiO2-Fc-CD

[0045] Characterize the material SiO2-Fc-CD synthesized in Example 1.

[0046] For the SiO2-Fc aqueous solution obtained in Example 1, use a three-electrode system. Among them, the three-electrode system uses a platinum electrode as the counter electrode, a silver-silver chloride electrode as the reference electrode, and a glassy carbon electrode as the working electrode. Add 20 mL of a 0.1 M KCl solution to the electrolytic cell as the electrolyte. Drop 5 μL of the SiO2-Fc aqueous solution (2 mg / mL) and 5 μL of the SiO2-Fc-CD aqueous solution (2 mg / mL) on the glassy carbon electrode respectively, and dry them in a silica gel box for two hours; then drop 5 μL of water on the electrode attached with the SiO2-Fc material. The electrode attached with the SiO2-Fc-CD material is divided into two parts. One part is dropped with 5 μL of water, and the other part is dropped with 5 μL of menthol solution (10 4The final pH of water and its aqueous solutions above nM) is 7.0. They are dried in a silica gel box for one hour, and then the current signal is detected using differential pulse voltammetry at this time. Meanwhile, the above electrode preparation steps are repeated to prepare the same differently modified electrodes, and the electrochemical signals are detected using cyclic voltammetry. Figure 2 A shows the curve graph verifying the principle of this method by differential pulse voltammetry; Figure 2 B shows the curve graph verifying the principle of this method by cyclic voltammetry.

[0047] 1) Drop the synthesized material, SiO2-Br aqueous solution, and SiO2-Fc aqueous solution onto a copper mesh for TEM testing. Figure 3 Figures are TEM images of SiO2-Br and SiO2-Fc. The inset in the upper left corner is the particle size test of the SiO2-Br material, and the obtained particle size is consistent with that of the TEM. The following figure is the mapping graph of the SiO2-Fc material, where purple, blue, red, yellow, and green represent the distribution of Si, O, C, Fe, and Br elements respectively.

[0048] 2) Conduct zeta potential analysis on the obtained material intermediates SiO2-Br and SiO2-Fc, as Figure 4 shown. The connection between the amino group and the bromine group causes the potential of the material to increase.

[0049] 3) The FT-IR of β-cyclodextrin, SiO2-Fc, and SiO2-Fc-CD is as Figure 5 shown. The peak around 1076 cm -1 belongs to ferrocene, and the peak around 3000 cm -1 belongs to cyclodextrin.

[0050] 4) The thermogravimetric analysis of SiO2-Fc-CD is as Figure 6 shown. There is a rapid degradation process between 275 - 355 °C, which is the decomposition stage of β-cyclodextrin. Then, the slow weight loss with the increase in temperature represents the decomposition of the silica precursor.

[0051] Example 3 Optimization of the pH of the reaction solution for the host-guest interaction between menthol and cyclodextrin and the concentration of the SiO2-Fc-CD material

[0052] The pH of the reaction solution for the host-guest interaction between menthol and cyclodextrin was optimized. The pH of the aqueous solution was adjusted using 1 M hydrochloric acid solution and measured with a pH meter. Reaction solutions with five different pH values of 6.5, 7.0, 7.5, 8.0, and 8.5 were obtained. The other reaction conditions, such as the concentration of SiO2-Fc-CD material, reaction temperature, and reaction time, were kept the same as those in Example 1 and Example 2. The difference in electrochemical signal intensity in the presence and absence of menthol at different pH values was measured to select the optimal pH condition. Using the differential pulse voltammetry detection method, the experimental parameter was set with the voltage scan range of 0 - 0.6 V, and the experimental sensitivity was selected as 10 -5 , after the parameter setting was completed, the three electrodes were inserted into the electrolyte solution, and the start button was clicked to measure its current signal, obtaining different current signal intensities at different pH values. By comparing the current intensities in the presence and absence of menthol, it can be concluded that the optimal effect is achieved at pH 7.0. Figure 7 Figure A shows the difference in current signal intensity at different pH values. It can be seen from the figure that under the same other conditions, the optimal reaction solution pH condition is pH 7.0.

[0053] Next, the concentration of SiO2-Fc-CD material was optimized. 1, 2, 3, 4, and 5 mg of SiO2-Fc-CD material were ultrasonically dispersed in 1 mL of aqueous solution to obtain different material concentrations of 1, 2, 3, 4, and 5 mg / mL. The other reaction conditions, such as reaction pH, reaction temperature, and reaction time, were kept the same as those in Example 1 and Example 2. The difference in electrochemical signal intensity in the presence and absence of menthol at different material concentrations was measured to select the optimal material concentration condition. The testing process was the same as above. By comparing the current intensities, it can be concluded that the optimal effect is achieved at a material concentration of 2 mg / mL. Figure 7 Figure B shows the difference in current signal intensity at different material concentrations. It can be seen from the figure that the optimal condition is to select a SiO2-Fc-CD material concentration of 2 mg / mL.

[0054] Establishment of the standard curve and sensitivity detection in Example 4

[0055] Menthol was dissolved in absolute ethanol to prepare a 1 M menthol solution, and then diluted to 10 2 -10 7Target molecule solution with nM series concentration gradients. Use a pipette to aspirate 5 μL of the SiO2-Fc-CD aqueous solution prepared in Example 1 and drop it onto the glassy carbon electrode, then insert the glassy carbon electrode into a box filled with silica gel. After one hour, aspirate 5 μL of menthol solutions (concentrations are 100 nM, 1 μM, 10 μM, 100 μM, 1 mM, 10 mM) and drop them onto the glassy carbon electrode. At this time, menthol and ferrocene compete because both can form host-guest interactions with cyclodextrin. In addition, use a pipette to take 5 μL of ultrapure water and drop it onto the modified glassy carbon electrode as a blank sample. Use a platinum electrode as the counter electrode, a silver-silver chloride electrode as the reference electrode, and a glassy carbon electrode as the working electrode in a three-electrode system to detect the target molecule electrochemically. Add 20 mL of 0.1 M KCl solution as the electrolyte to the electrode cell, and use differential pulse voltammetry as the detection method. Set the scanning voltage range to 0 - 0.6 V for the experimental parameters, and select an experimental sensitivity of 10 -5 . After the parameters are set, wait until the electrolyte is added, then click start to measure its current signal. Set three parallel samples for each concentration of the target molecule. After measurement, polish the electrode with alumina and then sonicate for 5 minutes. Figure 8 The curve graph of A is the electrochemical signal intensity corresponding to different concentrations of menthol in the system, Figure 8 The linear graph of B reflects the linear change of menthol within the detected concentration range, indicating good detection effect and feasibility. Compared with some existing detection methods, this method is the first to propose using electrochemistry to detect menthol, and it has a wider detection range and a lower detection limit. See Table 1.

[0056] Table 1

[0057]

[0058] Based on the above step conditions, replace the target molecule menthol with 0.1 M menthyl acetate, 0.1 M menthylamide, 0.1 M glucose, 0.1 M fructose, and 0.1 M glutamic acid respectively to verify the selectivity of this method, Figure 9 The structural formulas of these substances are listed. Menthyl acetate and menthylamide are menthol derivatives that change the hydroxyl group on menthol to an ester group and an amide bond respectively, and they are currently also used as cooling agents in many industries. Figure 10 The electrochemical detection results of menthol based on competing with ferrocene to enter β-cyclodextrin are shown. The competition of the above menthol derivatives and functional analogues with cyclodextrin is not significant, and they do not compete ferrocene out, resulting in very low measured electrochemical signal values.

[0059] Example 5 Detection of the spiked recovery of menthol in white sugar

[0060] To apply this method to actual samples, ordinary white sugar (product number: TGTZ002) was purchased from Suguo Supermarket. The white sugar was dissolved in ultrapure water, then shaken. The supernatant was taken to dissolve menthol for use. The spiking experiment was carried out within the linear range, and the actual sample was added at 10% of the total volume. 5 μL of the SiO2-Fc-CD aqueous solution (2 mg / mL) was dropped onto the glassy carbon electrode, and then the glassy carbon electrode was inserted into a box containing silica gel for color change. After one hour, menthol solutions with the actual sample diluted to final concentrations of 10 mM, 100 μM, and 100 nM were added dropwise and the reaction continued in the silica gel for color change. Using the differential pulse voltammetry detection method, the experimental parameters were set with a voltage scanning range of 0 - 0.6 V, and the experimental sensitivity was selected as 10 -5 , after the parameter settings were completed, the three electrodes were inserted into the electrolyte solution, the start button was clicked, and the current signal intensity was measured. The current signal intensity was substituted into the standard curve established in Example 4. The concentration results are shown in Table 2. The recovery rate was between 95 - 115%, and the RSD was less than 10. The results showed that this method had an acceptable recovery rate and relative standard deviation, indicating that the prepared method had good performance and could be used to detect menthol in actual samples.

[0061] Table 2

[0062]

[0063] Spiking Recovery Detection of Menthol in Essential Oil in Example 6

[0064] To apply this method to actual samples, essential oil (menthol content 0.25%) was purchased from the supermarket. The essential oil was dissolved in ultrapure water, then shaken for 30 minutes. The supernatant was taken to dissolve menthol for use. The spiking experiment was carried out within the linear range, and the actual sample was added at 10% of the total volume. All detection steps were the same as those in Example 5. The experimental results of the concentrations obtained based on the establishment of the standard curve in Example 4 are shown in Table 3. The recovery rate was between 80 - 105%, and the RSD was less than 10.

[0065] Table 3

[0066]

[0067] The results showed that this method had an acceptable recovery rate and relative standard deviation, indicating that the prepared method had good performance and could be used to detect menthol in actual samples.

Claims

1. An electrochemical detection method for menthol based on its competitive entry with ferrocene into β-cyclodextrin, characterized in that, It includes the following steps: 1) React tetraethyl orthosilicate, (3-bromopropyl)trimethoxysilane and triethylamine in a mixed solution of water and ethanol to obtain a precipitate, and then dry the precipitate to obtain silica microspheres with bromine groups; 2) React the silica microspheres with N,N-dimethylaminomethylferrocene in dichloromethane solution, wash the precipitate with absolute ethanol, and then dry the precipitate to obtain silica microspheres with ferrocene groups; 3) Dissolve the obtained silica microspheres with ferrocene groups in water, sonicate, then mix with an aqueous β-cyclodextrin solution, let it stand at room temperature and then centrifuge, and dissolve the dried precipitate in water to prepare an aqueous SiO2-Fc-CD solution; 4) Modify the prepared aqueous SiO2-Fc-CD solution on the surface of a glassy carbon electrode to obtain an electrochemical signal, drop different concentrations of menthol solutions, obtain different electrochemical signal intensities, and establish a relationship curve between the electrochemical signal intensity and the concentration of the menthol solution; 5) Modify the prepared aqueous SiO2-Fc-CD solution on the surface of a glassy carbon electrode, drop the target menthol solution to be measured, and obtain the concentration of the target menthol to be measured according to the electrochemical signal intensity obtained from the relationship curve in step 4).

2. The electrochemical detection method of menthol based on the competition with ferrocene for entering β-cyclodextrin according to claim 1, characterized in that In step 1), the mass ratio of tetraethyl orthosilicate to (3-bromopropyl)trimethoxysilane is 5:2, and the volume ratio of triethylamine, water and ethanol is 0.2:15:

15.

3. The electrochemical detection method of menthol based on competing with ferrocene for entering β-cyclodextrin according to claim 1, characterized in that, In step 2), the mass-volume ratio of N,N-dimethylaminomethylferrocene to dichloromethane solution is 35:30 mg / mL.

4. The electrochemical detection method of menthol based on competing with ferrocene for entering β-cyclodextrin according to claim 1, characterized in that, In step 3), the concentration of the aqueous β-cyclodextrin solution is 200 mg / mL, and the concentration of the aqueous SiO2-Fc-CD solution is 2 mg / mL.

5. The electrochemical detection method of menthol based on competing with ferrocene for entering β-cyclodextrin according to claim 1, characterized in that, The menthol concentration described in step 4) is 10 2 -10 7 nM.

6. The electrochemical detection method of menthol based on competing with ferrocene for entering β-cyclodextrin according to claim 1, characterized in that, The pH of the aqueous solutions and the menthol solution in steps 4) and 5) is 7.

0.

7. Application of the electrochemical detection method of menthol based on competing with ferrocene to enter β-cyclodextrin according to any one of claims 1-6 in the field of detection of foods or other products containing menthol.

8. The application according to claim 7, characterized in that, The menthol concentration is 10 2 -10 7 nM, and the electrolyte used for the electrochemical detection is a 0.1 M KCl solution.

9. The application according to claim 7, characterized in that, The foods include white sugar, and the other products containing menthol include essential oils.

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