An electrochemical detection method of p-hydroxybenzaldehyde

Abstract

The application belongs to the technical field of electrocatalysis, and specifically discloses an electrochemical detection method for p-hydroxybenzaldehyde (PHBA), which comprises the following steps: placing a modified manganese tetroxide modified glassy carbon electrode as a working electrode, a calomel electrode as a reference electrode and a platinum sheet electrode as an auxiliary electrode in a to-be-detected solution; obtaining a characteristic peak current value of the to-be-detected solution by using a differential pulse voltammetry method; and obtaining the content of the p-hydroxybenzaldehyde in the to-be-detected solution according to a linear relationship curve through the characteristic peak current value. The method provided by the application can accurately and efficiently detect the content of the p-hydroxybenzaldehyde in various to-be-detected samples, and has a wide linear range, a low detection limit and good anti-interference performance. The method has the advantages of high sensitivity and simple operation, and is suitable for analysis and detection in the fields of chemical industry, medicine and environment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrochemical analysis and detection, and particularly relates to an electrochemical detection method of p-hydroxybenzaldehyde. BACKGROUND

[0002] As an important organic synthesis intermediate, p-hydroxybenzaldehyde (PHBA) has a wide application in the fields of medicine, perfume, cosmetics, etc., and is a raw material of saphenamides, methoxybenzylamine pyrimidine and hydroxyl ampicillin (amoxicillin), and can also be used for synthesizing food flavor vanillin. However, PHBA has irritancy to human eyes, mucous membranes, respiratory systems and skin, so it is of great significance to develop a rapid, sensitive, accurate and efficient PHBA detection method for medical detection and analysis, food safety and environmental protection.

[0003] Existing PHBA detection methods include chromatography, mass spectrometry, spectrophotometry and fluorescence method, etc., which have problems such as complex operation, difficult sample processing and high cost of some instruments. In the analysis method using liquid chromatography-electrospray ionization-mass spectrometry (Anhui Medicine, 2010 (2): 157-159), the quantitative detection of PHBA is realized, and the detection limit is 0.063 μM, and the linear range is 10.0-150.0 μM. In the spectrophotometry (Journal of AOAC International, 2023, 106 (1): 26-33), the detection limit of PHBA is 2.68 μM, and the linear range is 4.90-10.77 μM. Electrochemical analysis and detection have the advantages of simple operation, high sensitivity and accuracy, and therefore are concerned, but there is no related report on the electrochemical detection of PHBA, which may be related to the lack of high-activity and high-selectivity catalysts. SUMMARY

[0004] The present application provides an electrochemical detection method of p-hydroxybenzaldehyde. The electrochemical method is used to detect and analyze p-hydroxybenzaldehyde for the first time. This method has the advantages of wide detection range, low cost, high sensitivity, fast detection speed and non-toxicity.

[0005] The present application is based on the catalytic oxidation of manganese oxides such as trimanganese tetraoxide on phenol and aldehyde. The manganese group is transformed between different valence states, and the gain and loss of electrons will cause the oxidation of X-OH and X-CHO on the benzene ring to generate X=O and X-COOH. The redox reaction is converted into an electrical signal under the induction of an electrochemical sensor, so as to achieve the quantitative analysis and detection of p-hydroxybenzaldehyde.

[0006] The present application provides an electrochemical detection method of p-hydroxybenzaldehyde, and the steps are as follows:

[0007] (1) Put the working electrode, reference electrode and auxiliary electrode into the liquid to be measured.

[0008] The working electrode is a modified manganese tetroxide modified glassy carbon electrode, the reference electrode is a mercury-mercury electrode, and the auxiliary electrode is a platinum electrode.

[0009] Further, the specific preparation steps of the modified manganese tetroxide modified glassy carbon electrode are as follows: the modified manganese tetroxide is dispersed in N,N-dimethylformamide, and after being configured into a modification solution with a concentration of 3 mg / ml, it is uniformly distributed on the surface of a glassy carbon electrode polished by 0.05 μm Al2O3 polishing powder and then washed, and the coating amount is 0.043-0.43 mg / cm 2 , and the modified manganese tetroxide modified glassy carbon electrode is obtained by drying with an infrared lamp.

[0010] Further, the specific preparation steps of the modified manganese tetroxide are as follows: manganese dioxide, carbon source, and cetyltrimethylammonium bromide are mixed as raw materials, deionized water is added, and then ultrasonic treatment is performed, ammonia water is used to adjust the pH value to 8, magnetic stirring is performed, then N,N-dimethylformamide is added as a cosolvent, and hydrothermal reaction is performed at 180-200 ℃ for 12-18 h, and then the modified manganese tetroxide is obtained after centrifugal washing, vacuum drying, and grinding treatment.

[0011] Further, the carbon source is one of urea, glucose, and citric acid, and urea is preferred.

[0012] Further, the mass ratio of cetyltrimethylammonium bromide, urea, and manganese dioxide is

[0013] 10:(1-1.5):(12-18).

[0014] Further, the volume ratio of the amount of deionized water and N,N-dimethylformamide in the reaction system is 5:3.

[0015] Preferably, the hydrothermal reaction temperature is 200 ℃, and the reaction time is 15 h.

[0016] Further, the magnetic stirring speed is 600 rpm, and the time is 60 min; the centrifugal washing solvent is N,N-dimethylformamide and deionized water, and the rotation speed is 8500 r / min.

[0017] (2) The characteristic peak current value of the liquid to be measured is obtained by using differential pulse voltammetry.

[0018] Further, the characteristic peak current value is the characteristic oxidation peak current value.

[0019] (3) The content of p-hydroxybenzaldehyde in the liquid to be measured is obtained by the characteristic peak current value according to the linear relationship curve.

[0020] Further, the method for establishing the linear relationship curve comprises:

[0021] placing the working electrode, the reference electrode and the auxiliary electrode in a preset gradient concentration of p-hydroxybenzaldehyde solution, then obtaining characteristic peak parameters of the preset gradient concentration of p-hydroxybenzaldehyde solution by using a differential pulse voltammetry method, and finally establishing a linear relationship curve according to the characteristic peak parameters corresponding to p-hydroxybenzaldehyde solutions of different concentrations.

[0022] Further, the p-hydroxybenzaldehyde solution is prepared by mixing p-hydroxybenzaldehyde and 0.1M PBS buffer solution, and the concentration is 0.025, 0.05, 0.1, 0.15, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8, 1 mmol / L.

[0023] Further, the scanning speed of the differential pulse voltammetry method is 0.1 V / s, the scanning current is 0.1 mA, and the scanning potential is 0.5-1.1 V.

[0024] The beneficial effects of the present application are:

[0025] The present application realizes, for the first time, the detection of p-hydroxybenzaldehyde by using an electrochemical method. Compared with the existing method for detecting p-hydroxybenzaldehyde, the present application can quickly and efficiently measure the content of p-hydroxybenzaldehyde, has a wider detection range, a detection limit of 2.45 μM, and a linear range of 25-1000 μM. Compared with ordinary manganese tetroxide, the electrode prepared from modified manganese tetroxide has higher stability, good selectivity and anti-interference in the electrochemical detection of p-hydroxybenzaldehyde. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The XRD pattern of the modified manganese tetroxide prepared in Example 2.

[0027] Figure 2 The SEM pattern of the modified manganese tetroxide prepared in Example 2.

[0028] Figure 3 The XPS pattern of the modified manganese tetroxide prepared in Example 2. 3 / 2 The positions of the two main peaks of Mn2p 1 / 2 region are 638.51 and 650.22, respectively, so the spin-orbit splitting energy between Mn2p 3 / 2 and Mn2p 1 / 2 is 11.71 eV Figure 3 B), which is consistent with the reported in the literature. The O1s spectrum has three peaks at 526.82, 528.21 and 528.87 eV Figure 3C), confirming the different chemical environment states of oxygen on the surface of the composite, which can be attributed to the bonding modes of C-O-C, Mn-O-C and Mn-O-Mn, respectively. The C1s spectrum shows three different peaks at 281.86, 282.91 and 286.52 eV (Figure 2C), confirming the different chemical environment states of oxygen on the surface of the composite, which can be attributed to the bonding modes of C-O-C, Mn-O-C and Mn-O-Mn, respectively. Figure 3 D), belonging to the bonding modes of C-C, C-O and C=O, confirming that C and Mn3O4 coexist in the modified trimanganese tetraoxide.

[0029] Figure 4 Figure 2E is a differential pulse voltammogram of the modified trimanganese tetraoxide modified bare glass electrode (GCE / M-Mn3O4) in 0.1 mM of p-hydroxybenzaldehyde solution in Example 2.

[0030] Figure 5 Figure 2F is a differential pulse voltammogram of the modified trimanganese tetraoxide modified bare glass electrode (GCE / M-Mn3O4) and bare glass electrode (GCE) in 0.1 mM of p-hydroxybenzaldehyde solution in Example 2.

[0031] Figure 6 Figure 2A and Figure 2B are differential pulse voltammograms of the ordinary trimanganese tetraoxide modified bare glass electrode (GCE / Mn3O4) in Comparative Example 1 and the unmodified trimanganese tetraoxide modified bare glass electrode (GCE / Mn3O4) in Comparative Example 2, respectively, in 0.1 mM of PBS, PHBA solution.

[0032] Figure 7 Figure 2E is a differential pulse voltammogram of the modified trimanganese tetraoxide modified bare glass electrode (GCE / M-Mn3O4) in 0.1 mM of p-hydroxybenzaldehyde solution in Example 2.

[0033] Figure 8 Figure 2E is a differential pulse voltammogram of the modified trimanganese tetraoxide modified bare glass electrode (GCE / M-Mn3O4) in 0.1 mM of p-hydroxybenzaldehyde solution in Example 2.

[0034] Figure 9 Figure 2E is a differential pulse voltammogram of the modified trimanganese tetraoxide modified bare glass electrode (GCE / M-Mn3O4) in 0.1 mM of p-hydroxybenzaldehyde solution in Example 2.

[0035] Figure 10 Figure 2E is a differential pulse voltammogram of the modified trimanganese tetraoxide modified bare glass electrode (GCE / M-Mn3O4) in 0.1 mM of p-hydroxybenzaldehyde solution in Example 2.

[0036] Figure 11The modified manganese tetraoxide modified bare glass electrode (GCE / M-Mn304) in Example 1-6 was subjected to differential pulse voltammetry detection in 0.1 mM of PHBA solution to obtain the corresponding current increment contrast graph. DETAILED DESCRIPTION

[0037] The application will be further described in conjunction with specific examples, but the embodiments of the application are not limited thereto.

[0038] Example 1

[0039] 1. Preparation of modified manganese tetraoxide modified glassy carbon electrode:

[0040] (1) 0.20 g of hexadecyl ammonium bromide, 0.025 g of urea, 25 ml of deionized water were mixed and ultrasonicated until clear; the mixed solution was adjusted to pH 8 with 25% ammonia water, and then 0.30 g of manganese dioxide was added to the mixed solution, which was stirred at 600 rpm for 60 min under magnetic stirring;

[0041] (2) The mixed solution prepared in step (1) was slowly added dropwise into 15 ml of N,N-dimethylformamide, and then transferred into a 100 mL polytetrafluoroethylene reaction kettle, and subjected to hydrothermal reaction at 200°C for 12 h; after natural cooling to room temperature, the product was washed with N,N-dimethylformamide and deionized water respectively for 3 times by centrifugation to obtain an intermediate product, the centrifugation speed was 8500 r / min, and the time was 5 min; the product was placed in a vacuum drying box, dried at a vacuum degree of 0.09 MPa and a temperature of 60°C for 24 h, and then ground into powder to obtain modified manganese tetraoxide;

[0042] (3) 3 mg of modified manganese tetraoxide was weighed, added into 1 ml of N,N-dimethylformamide, ultrasonicated for 10 min, and then configured into a glassy carbon electrode modification solution with a concentration of 3 mg / ml, and then dropped onto the surface of a glassy carbon electrode (diameter 3 mm, purchased from Frank Company, Japan) polished with 0.05 μm Al2O3 polishing powder and washed, and the coating amount was 0.129 mg / cm 2 , and dried with an infrared lamp to obtain a modified manganese tetraoxide modified glassy carbon electrode.

[0043] 2. Establishment of linear relationship curve of characteristic peak current value of p-hydroxybenzaldehyde and concentration relationship:

[0044] The p-hydroxybenzaldehyde is diluted with 0.1M PBS buffer to 0.025, 0.05, 0.1, 0.15, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8, 1 mmol / L standard solution 20 mL respectively, and the modified manganese tetroxide modified glassy carbon electrode, mercury electrode (purchased from Shanghai Huayu Instrument Company), platinum electrode (5mm*10mm*0.1mm, purchased from Beijing Jingke Company) are placed in the above different concentration standard solution, then the characteristic peak parameters of different concentrations of p-hydroxybenzaldehyde solution are obtained by differential pulse voltammetry, the scanning speed is 0.1V / s, and finally the linear relationship curve is established according to the characteristic peak parameters corresponding to different concentrations of p-hydroxybenzaldehyde solution, I p (μA) = 14.6901C PHBA (mM) + 1.6720(R 2 = 0.9976), wherein I p is the oxidation peak current value, C PHBA is the concentration of p-hydroxybenzaldehyde, the detection limit is 3.06μM, and the linear range is 25-1000μM.

[0045] 3. Detection of p-hydroxybenzaldehyde content in the test solution:

[0046] A 0.1mM PHBA solution is prepared with 0.1M PBS buffer as a solvent, 20mL of which is taken as a test solution, and a three-electrode system composed of a modified manganese tetroxide modified glassy carbon electrode, a mercury electrode and a platinum electrode is connected, then differential pulse voltammetry is used for measurement, and the corresponding current intensity I1 is recorded; then a three-electrode system composed of a glassy carbon electrode, a mercury electrode and a platinum electrode is connected, then differential pulse voltammetry is used for measurement, and the corresponding current intensity I0 is recorded; the current increment I1 / I0=1.55.

[0047] Example 2

[0048] The difference between Example 2 and Example 1 is that the hydrothermal reaction time in the preparation step (2) of the modified manganese tetroxide modified glassy carbon electrode is replaced by 15h.

[0049] Figure 4 The differential pulse voltammetry curves of p-hydroxybenzaldehyde at different concentrations corresponding to the modified manganese tetroxide modified glassy carbon electrode prepared in Example 2 are shown, and the oxidation peak current also gradually increases with the increase of the concentration of p-hydroxybenzaldehyde, and the two show a good linear relationship Figure 10 ): I p (μA) =

[0050] 15.9239C PHBA (mM) + 1.5943(R 2= 0.9972) with a detection limit of 2.45 μM, a linear range of 25-1000 μM and a current increment of I1 / I0 = 1.76.

[0051] Example 3

[0052] Example 3 differs from Example 1 in that the hydrothermal reaction time in the preparation step (2) of the modified trimanganese tetraoxide modified glassy carbon electrode is replaced by 18 h, and the current increment is I1 / I0 = 1.51.

[0053] Example 4

[0054] Example 4 differs from Example 1 in that the hydrothermal reaction temperature in the preparation step (2) of the modified trimanganese tetraoxide modified glassy carbon electrode is replaced by 180°C, and the current increment is I1 / I0 = 1.22.

[0055] Example 5

[0056] Example 5 differs from Example 1 in that the hydrothermal reaction time and temperature in the preparation step (2) of the modified trimanganese tetraoxide modified glassy carbon electrode are replaced by 15 h and 180°C, respectively, and the current increment is I1 / I0 = 1.41.

[0057] Example 6

[0058] Example 6 differs from Example 1 in that the hydrothermal reaction time and temperature in the preparation step (2) of the modified trimanganese tetraoxide modified glassy carbon electrode are replaced by 18 h and 180°C, respectively, and the current increment is I1 / I0 = 1.33.

[0059] Example 7

[0060] Example 7 differs from Example 1 in that the amount of the modified trimanganese tetraoxide coated in the preparation step (3) of the modified trimanganese tetraoxide modified glassy carbon electrode is 0.258 mg / cm 2 , and the current increment is I1 / I0 = 1.53.

[0061] Example 8

[0062] Example 8 differs from Example 1 in that the amount of the modified trimanganese tetraoxide coated in the preparation step (3) of the modified trimanganese tetraoxide modified glassy carbon electrode is 0.387 mg / cm 2 , and the current increment is I1 / I0 = 1.54.

[0063] Example 9

[0064] Example 9 differs from Example 1 in that the urea in the preparation step (1) of the modified trimanganese tetraoxide modified glassy carbon electrode is replaced by glucose, and the current increment is I1 / I0 = 1.42.

[0065] Example 10

[0066] Example 10 is different from Example 1 in that the preparation step (1) of the modified trimanganese tetroxide modified glassy carbon electrode is replaced with citric acid, and the current increment is: I1 / I0=1.41.

[0067] Comparative Example 1

[0068] 1. Preparation of a general trimanganese tetroxide modified glassy carbon electrode:

[0069] Take 3 mg of general trimanganese tetroxide (purchased from Zhejiang Zhiti Nanwei New Material Co., Ltd.), add 1 ml of N,N-dimethylformamide, and ultrasonic for 10 min to prepare a glassy carbon electrode modification solution with a concentration of 3 mg / ml. Drop it onto the surface of a glassy carbon electrode polished with 0.05 μm Al2O3 polishing powder and then cleaned, and the coating amount is 0.129 mg / cm 2 , and dry it with an infrared lamp to make a general trimanganese tetroxide modified glassy carbon electrode.

[0070] 2. Detection of the content of p-hydroxybenzaldehyde in the test solution:

[0071] Prepare a 0.1 mM PHBA solution with 0.1 M PBS buffer as the solvent; take 20 mL of 0.1 mM PHBA solution and 0.1 mM PBS solution as the test solution, respectively, and connect them to a three-electrode system composed of a general trimanganese tetroxide modified glassy carbon electrode, a calomel electrode, and a platinum sheet electrode. Then measure and record the response current intensity I1 using differential pulse voltammetry. Then connect them to a three-electrode system composed of a glassy carbon electrode, a calomel electrode, and a platinum sheet electrode. Then measure and record the response current intensity I0 using differential pulse voltammetry. The current increment I1 / I0=0.93.

[0072] Comparative Example 2

[0073] 1. Preparation of an unmodified trimanganese tetroxide modified glassy carbon electrode:

[0074] (1) Take 0.20 g of cetyltrimethylammonium bromide, mix it with 25 ml of deionized water and ultrasonic until clear; adjust the pH of the mixed solution to 8 with 25% ammonia water, and then add 0.30 g of manganese dioxide to the mixed solution and stir at 600 rpm for 60 min;

[0075] (2) The mixed solution prepared in step (1) is slowly added into 15 ml of N,N-dimethylformamide and then transferred into a 100 mL polytetrafluoroethylene reactor, and then subjected to hydrothermal reaction at 200°C for 15 h; after natural cooling to room temperature, the product is washed by centrifugation with N,N-dimethylformamide and deionized water respectively for 3 times, the centrifugal speed is 8500 r / min, and the time is 5 min; after being placed in a vacuum drying box, dried at a vacuum degree of 0.09 MPa and at 60°C for 24 h, and ground into powder, unmodified trimanganese tetroxide is obtained;

[0076] (3) 3 mg of unmodified trimanganese tetroxide is weighed, 1 ml of N,N-dimethylformamide is added, and ultrasonic treatment is performed for 10 min to prepare a glassy carbon electrode modification liquid with a concentration of 3 mg / ml; the glassy carbon electrode surface polished with 0.05 μm Al2O3 polishing powder and then cleaned is dropped with the glassy carbon electrode modification liquid, and the coating amount is 0.129 mg / cm 2 , and dried with an infrared lamp to prepare a glassy carbon electrode modified with ordinary trimanganese tetroxide.

[0077] 2. Detection of the content of p-hydroxybenzaldehyde in the test solution:

[0078] A 0.1 mM PHBA solution is prepared with 0.1 M PBS buffer as a solvent; 20 mL of the 0.1 mM PHBA solution and 0.1 mM PBS solution are taken as test solutions, respectively, and then connected to a three-electrode system composed of a glassy carbon electrode modified with unmodified trimanganese tetroxide, a calomel electrode, and a platinum sheet electrode; then, differential pulse voltammetry is used for measurement, and the response current intensity I1 is recorded; then, a three-electrode system composed of a glassy carbon electrode, a calomel electrode, and a platinum sheet electrode is connected; then, differential pulse voltammetry is used for measurement, and the response current intensity I0 is recorded; the current increment I1 / I0 is 1.34.

[0079] Table 1. Current increment (I1 / I0) generated by samples prepared from different carbon sources

[0080]

[0081] Table 2. Current increment (I1 / I0) of modified Mn3O4, ordinary Mn3O4, and unmodified Mn3O4

[0082]

[0083] Table 3. Actual peak current, theoretical peak current, and deviation rate of the modified trimanganese tetroxide modified bare glassy carbon electrode prepared in Example 2 for detection of PHBA with different concentrations

[0084]

[0085] As shown in Table 1, the samples prepared by using glucose and citric acid instead of urea as carbon source have catalytic property for detecting PHBA with the same concentration, which indicates that urea, glucose and citric acid can be used as carbon source in modified trimanganese tetroxide, and through the comparison of the increment of peak current in the examples, the effect of urea as carbon source is the most obvious.

[0086] As shown in Table 2, the purchased common trimanganese tetroxide has strong oxidation-reduction property and has no obvious electric signal for PHBA; the unmodified trimanganese tetroxide prepared without adding urea also has strong oxidation-reduction property and has weak electric signal for PHBA; the C-O-C, Mn-O-C and Mn-O-Mn bonds formed by adding urea as carbon source in the modified trimanganese tetroxide can produce strong electric signal in the electrocatalysis of PHBA.

[0087] It is found through the research that the performance of the modified trimanganese tetroxide in the hydrothermal reaction is mainly affected by the reaction temperature and reaction time, and the coating amount of the modified trimanganese tetroxide on the surface of the glassy carbon electrode has no obvious effect on the result. In addition, the unmodified trimanganese tetroxide itself has strong oxidation-reduction property Figure 6 ), which can produce strong electric signal in the standard PBS buffer solution and has strong interference, so the corresponding stability and anti-interference property are not discussed in depth. The samples prepared in each example are detected in the same concentration of PHBA solution to obtain the corresponding current increment Figure 11 ).

[0088] In order to verify that the glassy carbon electrode modified by the modified trimanganese tetroxide has good selectivity and anti-interference property, 0.1mM Vanillin solution and 0.1mM HBA solution are prepared by using 0.1M PBS buffer solution as solvent, 20mL Vanillin solution, HBA solution and 0.1M PBS buffer solution are taken as the to-be-detected solution, the three-electrode system composed of the glassy carbon electrode modified by the modified trimanganese tetroxide, the mercury electrode and the platinum electrode and the three-electrode system composed of the glassy carbon electrode, the mercury electrode and the platinum electrode are connected, and the differential pulse voltammetry method is used for measurement, and the test results are as shown in Table 3. Figure 7 、 8 、9.

[0089] The above examples only roughly study the reaction conditions and express several preferred examples of the present application, but are not used to limit the present application. It should be pointed out that the present application can also have various changes and modifications for the person skilled in the art, any modification, equivalent replacement, improvement, etc. made within the concept and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for electrochemical detection of p-hydroxybenzaldehyde, characterized by: It comprises the following steps: (1) taking the modified manganese tetroxide modified glassy carbon electrode as a working electrode, a mercury-mercury electrode as a reference electrode, and a platinum plate electrode as an auxiliary electrode, and placing them in a to-be-measured liquid; (2) obtaining the characteristic peak current value of the to-be-measured liquid by using a differential pulse voltammetry method; (3) obtaining the content of p-hydroxybenzaldehyde in the to-be-measured liquid according to the linear relationship curve through the characteristic peak current value; The preparation method of the modified manganese tetroxide modified glassy carbon electrode comprises the following specific steps: (1) mixing manganese dioxide, a carbon source, and hexadecyltrimethylammonium bromide according to a mass ratio of 10:(1-1.5):(12-18), adding deionized water after ultrasonic, adjusting the pH value to 8, stirring uniformly, adding a cosolvent N,N-dimethylformamide, and then performing a hydrothermal reaction, and after centrifugal washing, vacuum drying, and grinding treatment, a modified manganese tetroxide is obtained; (2) The modified trimanganese tetraoxide is dispersed in N,N-dimethylformamide to configure a modification liquid, which is uniformly distributed on the surface of the polished and cleaned glassy carbon electrode with a coating amount of 0.043-0.43 mg / cm 2 The modified trimanganese tetraoxide modified glassy carbon electrode is prepared by drying with an infrared lamp. The carbon source is one of urea, glucose, and citric acid.

2. The method of electrochemical detection of p-hydroxybenzaldehyde according to claim 1, characterized in that: The volume ratio of the amount of deionized water and N,N-dimethylformamide in step (1) is 5:

3.

3. The method of electrochemical detection of p-hydroxybenzaldehyde according to claim 1, characterized in that: The hydrothermal reaction temperature is 180-200 DEG C, and the reaction time is 12-18 h.

4. The method of electrochemical detection of p-hydroxybenzaldehyde according to claim 1, characterized in that: The characteristic peak current value is a characteristic oxidation peak current value.

5. The method of electrochemical detection of p-hydroxybenzaldehyde according to claim 1, characterized by: The method for establishing a linear relationship curve comprises the following steps: placing a working electrode, a reference electrode, and an auxiliary electrode in a preset gradient concentration p-hydroxybenzaldehyde solution, then obtaining the characteristic peak parameters of the preset gradient concentration p-hydroxybenzaldehyde solution by using a differential pulse voltammetry method, and finally establishing a linear relationship curve according to the characteristic peak parameters corresponding to p-hydroxybenzaldehyde solutions with different concentrations.

6. The method of electrochemical detection of p-hydroxybenzaldehyde according to claim 5, characterized in that: The solvent of the p-hydroxybenzaldehyde solution is a PBS buffer solution, and the pH value is 7.

7. The method of electrochemical detection of p-hydroxybenzaldehyde according to claim 5, characterized by: In the differential pulse voltammetry method, the scanning speed is 0.1 V / s, the scanning current is 0.1 mA, and the scanning potential is 0.5-1.1 V.

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