Preparation method and application of an electrochemiluminescence sensor for specifically detecting trilobatin

Abstract

The application belongs to the technical field of electrochemical analysis and detection, and discloses a preparation method and application of an electrochemiluminescence sensor for specifically detecting trilobatin. The specific operation includes: (1) preparing a composite material of nitrogen-doped carbon quantum dots (N-CDs) and a silver-based metal organic framework (AgMOF) (AgMOF@N-CDs); (2) modifying the AgMOF@N-CDs on a glassy carbon electrode to obtain AgMOF@N-CDs / GCE; and (3) based on a three-electrode system, using the AgMOF@N-CDs / GCE as a working electrode, a platinum wire as an auxiliary electrode, and Ag / AgCl as a reference electrode to construct an electrochemiluminescence sensor for detecting trilobatin. The preparation of the electrochemiluminescence sensor is simple, the analysis speed is relatively fast, the detection range is relatively wide, the sensitivity is relatively high, and the selectivity is relatively good.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electrochemical analysis and detection, and particularly relates to a method for specifically detecting trilobatin by using an electrochemiluminescence sensor. In particular, the present application relates to a composite material AgMOF@N-CDs obtained by encapsulating N-CDs prepared by a hydrothermal method in AgMOF, and dropping and coating the composite material on the surface of a glassy carbon electrode to obtain AgMOF@N-CDs / GCE, and then using AgMOF@N-CDs / GCE as a sensing element to construct an electrochemiluminescence sensor for quantitatively and specifically detecting trilobatin. BACKGROUND

[0002] Traditional methods for detecting trilobatin mainly include high performance liquid chromatography (HPLC), nuclear magnetic resonance spectroscopy (NMR), high performance liquid chromatography-mass spectrometry (HPLC-MS), etc. However, these methods have some disadvantages, such as: expensive instruments and equipment, high detection cost; complex operation, requiring professional personnel to operate; long detection time. Therefore, it is of high application value to establish a simple, rapid and sensitive method for detecting trilobatin.

[0003] At present, there are few reports on detecting trilobatin by using electrochemiluminescence method. Based on the advantages of electrochemiluminescence method, it is a better new approach to construct an electrochemiluminescence sensor for detecting trilobatin. The success of constructing a sensitive electrochemiluminescence sensor depends on whether an excellent luminescent body is used. As a zero-dimensional carbon-based luminescent material, nitrogen-doped carbon quantum dots (N-CDs) are non-toxic, have high quantum yield, and are biocompatible. In addition, there are amino groups on the surface of N-CDs, which can form hydrogen bonds with the hydroxyl groups in the trilobatin molecule, so that N-CDs can be used as a luminescent body for constructing an electrochemiluminescence sensor. However, due to its strong water solubility, the stability of N-CDs is poor when tested in an aqueous electrolyte, and the stability needs to be further improved so that N-CDs can be firmly fixed on the electrode.

[0004] Silver-based metal organic framework (AgMOF) is a kind of porous material prepared by Ag +The MOF material synthesized with 1,3,5-benzene tricarboxylic acid has a simple synthesis method, a short time consumption and only needs to be carried out at room temperature without heating conditions, and the AgMOF itself also has certain electrochemiluminescence performance and better catalytic activity. Therefore, when preparing the AgMOF, N-CDs are doped to enable the N-CDs to be encapsulated in the AgMOF to prepare the AgMOF@N-CDs composite material. Based on the AgMOF@N-CDs composite material as a luminophore to construct an electrochemiluminescence sensor, the AgMOF with a larger specific surface area and higher porosity can encapsulate more N-CDs, effectively improving the electrochemiluminescence stability of the material; the combination of the AgMOF with better catalytic activity and the nitrogen-doped carbon quantum dots (N-CDs) further enhances the electrochemiluminescence response of the material, so that the constructed sensor has higher sensitivity. In addition, the N-CDs encapsulated in the AgMOF@N-CDs contain amino groups that have a hydrogen bond effect with hydroxyl groups in the forsterite molecules, and there is an electrostatic adsorption effect between the AgMOF@N-CDs and the forsterite, so that the electrochemiluminescence sensor can selectively detect forsterite. The published Chinese patent CN117233229A constructs a molecularly imprinted electrochemiluminescence sensor to detect forsterite based on g-C3N4@NiMOF, which has a lower detection limit, but the molecular imprinting process includes monomer polymerization, template molecule imprinting, template elution and specific adsorption again, and the preparation process is relatively complex and long, and a large amount of forsterite standard is consumed during preparation, which is high in cost; at the same time, the sensor needs to be specifically enriched with forsterite before detecting forsterite, and a certain period of time is needed to reach the adsorption balance of the electrode, and then quantitative analysis is carried out after the adsorption is completed, which is relatively complicated and time-consuming. The method of the present application can prepare and store the AgMOF@N-CDs modified electrode material in advance, and only needs to drop the modified electrode material on the surface of a glassy carbon electrode to complete the preparation of a sensor for selectively detecting forsterite. The present application only needs to place the prepared sensor in a small amount of to-be-detected liquid for direct testing, the sensor has high response degree and fast detection speed, and the whole detection process can be completed within 2-5 minutes. The sensor preparation process is simple and convenient, and the construction cost is low, which is suitable for large-scale application. In addition, the patent CN117233229A detects forsterite based on the molecular imprinting technology, while the present application realizes specific detection of forsterite based on the hydrogen bond and electrostatic adsorption between AgMOF@N-CDs and forsterite, has higher specific recognition rate and faster speed.

[0005] The application obtains AgMOF@N-CDs / GCE by dropping and coating AgMOF@N-CDs dispersion liquid on the surface of a bare GCE, and drying under infrared light and the like. An electrochemical luminescence sensor is constructed by using a three-electrode system, taking AgMOF@N-CDs / GCE as a working electrode, a platinum wire electrode as an auxiliary electrode, and Ag / AgCl as a reference electrode, and the performance of the AgMOF@N-CDs / GCE sensor in detecting trilostane is tested. The sensor has the advantages of simple operation, good stability, fast analysis speed, good selectivity, low cost, high sensitivity and the like, and is an effective new way for specific quantitative analysis of trilostane. SUMMARY

[0006] The first object of the application is to provide a preparation method of an electrochemical luminescence sensor for specific detection of trilostane, and the second object is to provide an application method of the electrochemical luminescence sensor for specific detection of trilostane.

[0007] The preparation method of the first object of the application is to take AgMOF@N-CDs / GCE as a working electrode, Ag / AgCl electrode as a reference electrode, and platinum wire electrode as an auxiliary electrode to form a three-electrode system. Based on the ECL response of AgMOF@N-CDs / GCE before and after detecting trilostane, sensitive and selective quantitative detection of trilostane is realized, and the sensor has the advantages of simple operation, wide detection range, fast detection speed, good selectivity, low cost, high sensitivity and convenient carrying.

[0008] The above technical objects of the application are achieved by the following technical solutions:

[0009] The preparation method of the electrochemical luminescence sensor for specific detection of trilostane provided by the application takes AgMOF@N-CDs / GCE as a working electrode, and constructs an electrochemical luminescence sensor based on AgMOF@N-CDs / GCE to detect trilostane.

[0010] Further, the preparation method of the AgMOF@N-CDs / GCE electrochemical luminescence sensor is as follows: a glassy carbon electrode is polished, and then ultrasonically cleaned with anhydrous ethanol and deionized water, and dried at room temperature to obtain a clean glassy carbon electrode for standby use; AgMOF@N-CDs DMF dispersion liquid is moved by a microsyringe and modified on the surface of the pretreated glassy carbon electrode, and dried under an infrared lamp to obtain AgMOF@N-CDs / GCE.

[0011] Further, the operation steps of the preparation method of AgMOF@N-CDs are as follows:

[0012] S1. Dissolve urea and citric acid in deionized water to form a uniform solution, then move the mixed solution to a reaction kettle, react at 180 DEG C, after the reaction is completed, cool to room temperature, centrifuge, purify by dialysis, and freeze-dry to obtain N-CDs;

[0013] The mass ratio of urea to citric acid is 1:1-1:6, and the reaction time is 1-8h. The nitrogen-doped carbon quantum dots (N-CDs) are a zero-dimensional carbon-based luminescent material with non-toxicity, high quantum yield and good biocompatibility. The amino groups on the surface of the N-CDs can form firm hydrogen bonds with the hydroxyl groups in the trilostane molecules, so that the N-CDs have strong ECL intensity and can selectively identify trilostane molecules.

[0014] S2. Dissolve 1,3,5-benzene tricarboxylic acid in ethanol to obtain solution A, dissolve silver nitrate in deionized water to obtain solution B, mix solution A and solution B and add the prepared N-CDs powder, stir at 25 DEG C, after the reaction is completed, centrifuge, wash with ethanol, and vacuum dry at 60 DEG C for 12h to obtain AgMOF@N-CDs.

[0015] The mass ratio of 1,3,5-benzene tricarboxylic acid, silver nitrate and N-CDs is 10:10:1-100:100:1, and the reaction time is 0.5-5h.

[0016] The diameter of the glassy carbon electrode used is 3mm; the concentration of the DMF dispersion solution of the AgMOF@N-CDs is 0.5-3.0mg / mL, and the drop coating amount is 2.5-10μL.

[0017] The AgMOF prepared in the scheme has the characteristics of large specific surface area and high porosity, can encapsulate N-CDs in the organic framework with Ag + as the center, and can effectively solve the phenomenon of unstable ECL caused by the dissolution of N-CDs in the water system. Meanwhile, the catalytic effect of Ag + further stimulates the synergistic effect of AgMOF and N-CDs, and further enhances the ECL performance. The N-CDs encapsulated in the AgMOF@N-CDs contain amino groups and hydroxyl groups in the trilostane molecules, and there is a hydrogen bond effect, and there is an electrostatic adsorption effect between AgMOF@N-CDs and trilostane, so that the electrochemiluminescence sensor can sensitively and stably selectively and quantitatively detect trilostane.

[0018] The second object of the present application is to provide an application method of the electrochemiluminescence sensor for specifically detecting trilostane, which has the same effect.

[0019] The above technical effects of the present application are realized by the following technical scheme:

[0020] The application provides an application method of an electrochemiluminescence sensor for specifically detecting trilobatin, an AgMOF@N-CDs / GCE is used as a working electrode, a platinum wire electrode is used as an auxiliary electrode, and Ag / AgCl is used as a reference electrode, in a three-electrode system, electrochemiluminescence intensity in electrolyte solutions containing different concentrations of trilobatin is determined by an electrochemiluminescence method, and trilobatin is quantitatively detected.

[0021] As the preferred technical solution, the specific steps are as follows:

[0022] A1. Preparation of trilobatin standard solution with different concentrations:

[0023] A trilobatin standard solution with different concentrations is prepared by using 0.1M PBS buffer solution containing 0.05M potassium persulfate with pH 7.0 to prepare a 1×10 -3 M solution of trilobatin standard, and a series of trilobatin standard solutions with different concentrations are diluted, and the concentration range is 1×10 -7 ~ 1×10 - 3 M;

[0024] A2. Drawing of a standard curve:

[0025] An AgMOF@N-CDs / GCE is used as a working electrode, a platinum wire electrode is used as an auxiliary electrode, and Ag / AgCl is used as a reference electrode to form a three-electrode system, 0.1M PBS buffer solution containing 0.05M K2S2O8 with pH 7.0 is used as a blank solution to detect electrochemiluminescence intensity, then the blank solution is placed in a series of trilobatin standard solutions with different concentrations prepared in step A1, in an electrochemical window range of-1.8-0V, a photomultiplier high voltage is 800V, a scanning speed is 0.1V / s, cyclic voltammetry scanning is performed, electrochemiluminescence intensity-time curves (ECL-Time) are recorded, a linear relationship between a difference value of luminescence intensity before and after the sensor detects trilobatin and a logarithmic value of the concentration of trilobatin is established, and a corresponding linear regression equation is obtained.

[0026] A3. Actual sample detection:

[0027] A trilobatin crude extract is diluted by using 0.1M PBS buffer solution containing 0.05M K2S2O8 with pH 7.0 to obtain a sample to be detected, electrochemiluminescence testing is performed on trilobatin in the actual sample by using a standard addition method, and the concentration of trilobatin in the sample to be detected is calculated according to the linear regression equation obtained in A2.

[0028] As the preferred technical solution, the detection range of trilobatin is 1×10 -7 ~ 1×10 -3 M, the minimum detection limit is 6.0×10 -8 M.

[0029] In summary, the present application has the following beneficial effects:

[0030] The electrochemiluminescence sensor constructed based on the AgMOF@N-CDs composite material, the N-CDs are encapsulated in the AgMOF by the N-CDs and AgMOF composite, the dissolution and shedding of the N-CDs modified on the GCE in the aqueous electrolyte during the detection are effectively reduced, and the stability of the material is improved; the AgMOF with Ag as the center has strong catalytic performance, and the ECL performance is further stimulated, and the sensitivity of the sensor is improved; the N-CDs encapsulated in the AgMOF@N-CDs contain amino groups, and there is a hydrogen bond effect between the hydroxyl groups in the trilobite; the composite material AgMOF@N-CDs and the trilobite exist electrostatic adsorption effect, so that the sensor can selectively detect the trilobite. +

[0031] The sensitive electrochemiluminescence method for selectively detecting trilobite proposed in the present application can replace the traditional methods such as high-performance liquid chromatography and nuclear magnetic resonance with high equipment cost and long detection period, has the advantages of simple operation, fast detection speed, wide linear range, good selectivity, low cost, high sensitivity and the like, and promotes the application of the electrochemiluminescence sensor in the detection of trilobite. BRIEF DESCRIPTION OF DRAWINGS

[0032] The accompanying drawings are used to provide a further understanding of the present application, and constitute a part of the specification, together with the embodiments of the present application, to explain the present application, and do not constitute a limitation of the present application.

[0033] Figure 1 is a brief flowchart of the preparation of the AgMOF@N-CDs / GCE electrochemiluminescence sensor and the detection of trilobite;

[0034] Figure 2 is the ECL curve of the AgMOF@N-CDs / GCE electrochemiluminescence sensor and the AgMOF@N-CDs / GCE detection of 10 -4 M trilobite;

[0035] Figure 3 is the ECL curve of the AgMOF@N-CDs / GCE electrochemiluminescence sensor for detecting different concentrations of trilobite (the concentration range of trilobite is: 1×10 -7 ~ 1×10 -3 M);

[0036] Figure 4 is the calibration curve of the AgMOF@N-CDs / GCE electrochemiluminescence sensor for detecting different concentrations of trilobite;

[0037] Figure 5 ​ECL curve of AgMOF / GCE electrochemiluminescence sensor is

[0038] Figure 6 ECL curve of AgMOF / GCE electrochemiluminescence sensor is

[0039] Figure 7 The selective histogram of AgMOF@N-CDs / GCE electrochemiluminescence sensor is DETAILED DESCRIPTION

[0040] In order to further illustrate the technical means and effects taken by the present application to achieve the predetermined object, the specific implementation, features and effects of the preparation method and application of the electrochemiluminescence sensor for detecting trilobatin according to the present application are described in detail as follows.

[0041] Example 1: Preparation method and application method of the electrochemiluminescence sensor for detecting trilobatin.

[0042] Preparation method of the electrochemiluminescence sensor for detecting trilobatin:

[0043] (1) Preparation method of AgMOF@N-CDs:

[0044] S1. Dissolve urea and citric acid in 30 mL of deionized water to form a uniform solution, then move the mixed solution to a reaction kettle, react at 180℃, after the reaction is completed, cool to room temperature, centrifuge, purify by dialysis, and freeze-dry to obtain N-CDs;

[0045] wherein, the mass ratio of urea to citric acid is 1:3, i.e. the mass of urea and citric acid is 1 g and 3 g respectively, and the reaction time is 5 h;

[0046] S2. Dissolve 1,3,5-benzene tricarboxylic acid in 10 mL of ethanol to obtain solution A; dissolve silver nitrate in 10 mL of deionized water to obtain solution B; mix solution A and solution B and add the prepared N-CDs powder, stir at 25℃, after the reaction is completed, centrifuge, wash with ethanol, and vacuum dry at 60℃ for 12 h to obtain AgMOF@N-CDs;

[0047] wherein, the mass ratio of 1,3,5-benzene tricarboxylic acid, silver nitrate and N-CDs is 50:50:1, i.e. the mass of 1,3,5-benzene tricarboxylic acid, silver nitrate and N-CDs is 0.25 g, 0.25 g and 5 mg respectively, and the reaction time is 1.5 h.

[0048] (2) Preparation method of AgMOF@N-CDs / GCE is:

[0049] The glassy carbon electrode was polished, and then ultrasonically cleaned with anhydrous ethanol solution and deionized water for 15 min, and dried at room temperature to obtain a pretreated glassy carbon electrode; 5 μL of 1 mg / mL AgMOF@N-CDs DMF dispersion was transferred to the surface of a clean glassy carbon electrode with a diameter of 3 mm using a microsyringe, and dried under an infrared lamp to obtain AgMOF@N-CDs / GCE; the prepared electrochemiluminescence sensor was named AgMOF@N-CDs / GCE;

[0050] An application method of an electrochemiluminescence sensor for detecting trilobatin;

[0051] AgMOF@N-CDs / GCE was used as the working electrode, a platinum wire electrode was used as the auxiliary electrode, and Ag / AgCl was used as the reference electrode; the electrochemiluminescence intensity of the modified electrode before and after detecting trilobatin was tested by cyclic voltammetry scanning (electrochemical window: -1.8 V-0 V; photomultiplier high voltage: 800 V; scan rate: 0.1 V / s) under a three-electrode system;

[0052] The electrochemiluminescence sensor prepared based on AgMOF@N-CDs / GCE detected trilobatin; the electrochemiluminescence intensity of the electrolyte containing trilobatin was compared with the electrochemiluminescence intensity of the electrolyte without trilobatin, and the electrochemiluminescence signal intensity was obviously reduced, that is, the quenching value of the electrochemiluminescence intensity of the sensor for detecting trilobatin was large, and the results are shown in Figure 2 , which shows that the sensitivity of the AgMOF@N-CDs / GCE electrochemiluminescence sensor for selectively detecting trilobatin is high.

[0053] As a preferred embodiment of the above technical solution, the specific steps are as follows:

[0054] A1. Preparation of trilobatin standard solution with different concentrations:

[0055] A series of trilobatin standard solutions with different concentrations were prepared by diluting a 1×10 -3 M solution of trilobatin standard with 0.1 M PBS buffer solution containing 0.05 M potassium persulfate at pH 7.0, and the concentration range was 1×10 -7 -1×10 - 3 M;

[0056] A2. Drawing of standard curve:

[0057] A three-electrode system was constructed using AgMOF@N-CDs / GCE as the working electrode, a platinum wire electrode as the auxiliary electrode, and Ag / AgCl as the reference electrode. Electrochemiluminescence intensity was detected using 0.1M PBS buffer (pH 7.0) containing 0.05M K₂S₂O₈ as the blank solution. The solution was then placed in a series of trifolin standard solutions of different concentrations prepared in step A1. Cyclic voltammetry was performed within an electrochemical window of -1.8 to 0V, with a photomultiplier tube voltage of 800V and a scan rate of 0.1V / s. The electrochemiluminescence intensity-time curve (ECL-Time) was recorded. A linear relationship was established between the difference in luminescence intensity (ΔECL) before and after trifolin detection and the logarithm of the trifolin concentration, yielding the corresponding linear regression equation. When the trifolin concentration was 1×10⁻⁶... -7 ~1×10 -3 When M is between, the electrochemiluminescence intensity decreases with increasing concentration, such as Figure 3 As shown, ΔECL exhibits a good linear relationship with the logarithm of trifolin concentration. Figure 4 The linear regression equation is ΔECL = 2865.55Log C(M) + 23039.90, and the correlation coefficient (R²) is... 2 The value was 0.9942, and the detection limit was 6.0 × 10⁻⁶. -8 M;

[0058] A3. Actual sample testing:

[0059] Five g of *Ligustrum lucidum* leaf sample was added to 100 mL of deionized water at a solid-liquid ratio of 1:20. After extraction by heating and reflux for 3 h, the sample was filtered under reduced pressure to obtain the filtrate. The filtrate was then diluted to 100 mL to obtain the crude extract of trifolin for later use. 0.1 mL of the crude extract was diluted to 100 mL with 0.1 M PBS buffer solution containing 0.05 M K2S2O8 at pH 7.0 to obtain the sample to be tested. The sample was used for ECL detection. The concentration of trifolin in the sample to be tested was calculated according to the linear regression equation obtained in A2 above. The results are listed in Table 1.

[0060] In Example 1, AgMOF@N-CDs was used as the electrode modification material. Based on the high electrochemiluminescence performance of N-CDs and the good chemical stability, high porosity, excellent catalytic activity, and large specific surface area of ​​AgMOF, the composite material exhibits strong and stable electrochemiluminescence performance. The electrochemiluminescence sensor constructed based on the AgMOF@N-CDs / GCE chemically modified electrode demonstrates superior performance in detecting trifolin, exhibiting higher sensitivity, better stability, a wider linear range, a lower detection limit, and better selectivity.

[0061] Comparative Example 1: A method for preparing and applying an electrochemiluminescence sensor for detecting trifolin.

[0062] A preparation method of an electrochemiluminescence sensor for detecting trilobatin:

[0063] (1) A preparation method of AgMOF@N-CDs2:

[0064] The preparation method of N-CDs is the same as S1 of step (1) of Example 1;

[0065] The preparation method of AgMOF@N-CDs2 is the same as S2 of step (1) of Example 1, wherein the mass ratio of 1,3,5-benzenetricarboxylic acid, silver nitrate and N-CDs is 1:1:0.12, that is, the mass of 1,3,5-benzenetricarboxylic acid, silver nitrate and N-CDs is 0.25 g, 0.25 g and 30 mg respectively, and the prepared material is named as AgMOF@N-CDs2;

[0066] (2) The preparation method of AgMOF@N-CDs2 / GCE is:

[0067] The preparation method of AgMOF@N-CDs2 / GCE is the same as step (2) of Example 1, wherein the dispersion solution taken by the microsyringe is 1 mg / mL AgMOF@N-CDs2 DMF dispersion solution;

[0068] An application method of an electrochemiluminescence sensor for detecting trilobatin:

[0069] AgMOF@N-CDs2 / GCE is used as a working electrode, a platinum wire electrode is used as an auxiliary electrode, and Ag / AgCl is used as a reference electrode, and the electrochemiluminescence intensity before and after the modified electrode detects trilobatin is tested by cyclic voltammetry scanning (electrochemical window: -1.8V-0V; photomultiplier high voltage: 800V; scan rate: 0.1V / s) in a three-electrode system;

[0070] The specific application method is the same as that of Example 1, and the results of the sensor detecting trilobatin in the actual sample are listed in Table 1.

[0071] Comparative Example 2: A preparation method and application method of an electrochemiluminescence sensor for detecting trilobatin.

[0072] A preparation method of an electrochemiluminescence sensor for detecting trilobatin:

[0073] (1) A preparation method of AgMOF@N-CDs3:

[0074] The preparation method of N-CDs is the same as S1 of step (1) of Example 1;

[0075] The preparation method of AgMOF@N-CDs3 is the same as that of S2 in step (1) of Example 1, wherein the mass ratio of 1,3,5-benzenetricarboxylic acid, silver nitrate and N-CDs is 1:1:0.008, that is, the mass of 1,3,5-benzenetricarboxylic acid, silver nitrate and N-CDs is 0.25 g, 0.25 g and 2 mg respectively, and the prepared material is named as AgMOF@N-CDs3;

[0076] The preparation method of AgMOF@N-CDs3 / GCE is the same as that of step (2) in Example 1, wherein the dispersion solution taken by the microsyringe is a DMF dispersion solution of 1 mg / mL AgMOF@N-CDs3;

[0077] The preparation method of AgMOF@N-CDs3 / GCE is the same as that of step (2) in Example 1, wherein the dispersion solution taken by the microsyringe is a DMF dispersion solution of 1 mg / mL AgMOF@N-CDs3;

[0078] An application method of an electrochemiluminescence sensor for detecting trilobatin:

[0079] AgMOF@N-CDs3 / GCE is used as a working electrode, a platinum wire electrode is used as an auxiliary electrode, and Ag / AgCl is used as a reference electrode, and the electrochemiluminescence intensity of the modified electrode before and after detecting trilobatin is tested in a three-electrode system through cyclic voltammetry scanning (electrochemical window: -1.8V-0V; photomultiplier high voltage: 800V; scan rate: 0.1V / s);

[0080] The specific application method is the same as that of Example 1, and the results of the sensor in detecting trilobatin in an actual sample are shown in Table 1.

[0081] A preparation method and an application method of an electrochemiluminescence sensor for detecting trilobatin.

[0082] A preparation method of an electrochemiluminescence sensor for detecting trilobatin:

[0083] The preparation method of N-CDs is the same as that of S1 in step (1) of Example 1;

[0084] The preparation method of N-CDs is the same as that of S1 in step (1) of Example 1;

[0085] The preparation method of N-CDs / GCE is:

[0086] A glassy carbon electrode is polished and ultrasonically cleaned with anhydrous ethanol solution and deionized water for 15 minutes respectively, and is blown dry at room temperature to obtain a pretreated glassy carbon electrode for standby use; 5 μL of a DMF dispersion solution of 1 mg / mL N-CDs is taken by a microsyringe and modified on the surface of a clean glassy carbon electrode with a diameter of 3 mm, and is dried under an infrared lamp to obtain N-CDs / GCE;

[0087] An application method of an electrochemiluminescence sensor for detecting trilobatin:

[0088] N-CDs / GCE as working electrode, platinum wire electrode as auxiliary electrode, Ag / AgCl as reference electrode, under three-electrode system, through cyclic voltammetry scanning (electrochemical window: -1.8V-0V; photomultiplier high voltage: 800V; scan rate: 0.1V / s) test the electrochemiluminescence intensity of the modified electrode before and after the detection of trilostane;

[0089] The specific application method is the same as that in Example 1, the electrochemiluminescence intensity curve of the sensor is shown in Figure 5 , and the results of the sensor in detecting trilostane in actual samples are listed in Table 1.

[0090] The single N-CDs has a certain electrochemiluminescence signal, but its stability is poor, and the electrochemiluminescence intensity gradually decreases with the extension of the test time during the test. This is because N-CDs has strong hydrophilicity and water solubility, which will gradually fall off from the surface of the sensor in the test solution, thereby causing a sharp change in ECL intensity (RSD = 89.31).

[0091] Comparative Example 4: A preparation method and application method of an electrochemiluminescence sensor for detecting trilostane.

[0092] A preparation method of an electrochemiluminescence sensor for detecting trilostane:

[0093] (1) A preparation method of AgMOF:

[0094] The preparation method of AgMOF is as follows: 0.25g of 1,3,5-benzene tricarboxylic acid is dissolved in 10mL of ethanol to obtain solution A; 0.25g of silver nitrate is dissolved in 10mL of deionized water to obtain solution B; solution A and solution B are mixed, stirred at 25℃ for 1.5h, after the reaction is completed, centrifuged, washed with ethanol, and then vacuum dried at 60℃ for 12h to obtain AgMOF;

[0095] (2) The preparation method of AgMOF / GCE is as follows:

[0096] The glassy carbon electrode is polished and ultrasonically cleaned with anhydrous ethanol solution and deionized water for 15min, and then dried at room temperature to obtain a pretreated glassy carbon electrode for standby use; 5μL of 1mg / mL AgMOF DMF dispersion solution is transferred to the surface of a clean glassy carbon electrode with a diameter of 3mm using a microsyringe, and dried under an infrared lamp to obtain AgMOF / GCE;

[0097] An application method of an electrochemiluminescence sensor for detecting trilostane:

[0098] AgMOF / GCE as the working electrode, platinum wire electrode as auxiliary electrode, Ag / AgCl as reference electrode, in a three-electrode system, through cyclic voltammetry scanning (electrochemical window: -1.8V~0V; photomultiplier high voltage: 800V; scan rate: 0.1V / s) test modified electrode detection before and after the electrochemiluminescence intensity of trilostane;

[0099] The specific application method is the same as that in Example 1, the electrochemiluminescence intensity curve of the sensor is shown in Figure 6 Table 1, and the results of the sensor detecting trilostane in actual samples are shown in Table 1.

[0100] Preparation method and application method of an electrochemiluminescence sensor for detecting trilostane.

[0101] Preparation method of an electrochemiluminescence sensor for detecting trilostane:

[0102] (1) Preparation method of N-CDs and AgMOF:

[0103] The preparation method of N-CDs is the same as S1 in step (1) of Example 1.

[0104] The preparation method of AgMOF is the same as step (1) of Comparative Example 4.

[0105] (2) Preparation method of AgMOF / N-CDs / GCE is:

[0106] The glassy carbon electrode was polished and ultrasonically cleaned with anhydrous ethanol solution and deionized water for 15 min, and then dried at room temperature to obtain a pretreated glassy carbon electrode; 5 μL of 1 mg / mL N-CDs DMF dispersion was transferred to the surface of a clean glassy carbon electrode with a diameter of 3 mm using a microsyringe, and dried under an infrared lamp to obtain N-CDs / GCE; 5 μL of 1 mg / mL AgMOF DMF dispersion was then transferred to the electrode using a microsyringe to obtain AgMOF / N-CDs / GCE; the prepared electrochemiluminescence sensor was named AgMOF / N-CDs / GCE.

[0107] Application method of an electrochemiluminescence sensor for detecting trilostane:

[0108] AgMOF / N-CDs / GCE as the working electrode, platinum wire electrode as auxiliary electrode, Ag / AgCl as reference electrode, in a three-electrode system, through cyclic voltammetry scanning (electrochemical window: -1.8V~0V; photomultiplier high voltage: 800V; scan rate: 0.1V / s) test modified electrode detection before and after the electrochemiluminescence intensity of trilostane;

[0109] The specific application method is the same as that in Example 1, and the results of the sensor detecting trilobatin in actual samples are shown in Table 1.

[0110] Preparation method and application method of an electrochemiluminescence sensor for detecting trilobatin.

[0111] Preparation method of an electrochemiluminescence sensor for detecting trilobatin:

[0112] (1) Preparation method of N-CDs and AgMOF:

[0113] The preparation method of N-CDs is the same as S1 in step (1) of Example 1;

[0114] The preparation method of AgMOF is the same as step (1) of Comparative Example 4;

[0115] (2) Preparation method of N-CDs / AgMOF / GCE is:

[0116] The glassy carbon electrode was polished and ultrasonically cleaned with anhydrous ethanol solution and deionized water for 15 min, and then dried at room temperature to obtain a pretreated glassy carbon electrode; 5 μL of 1 mg / mL AgMOF DMF dispersion was transferred to the surface of a clean glassy carbon electrode with a diameter of 3 mm using a microsyringe, and dried under an infrared lamp to obtain AgMOF / GCE; 5 μL of 1 mg / mL N-CDs DMF dispersion was then transferred to the electrode using a microsyringe to obtain N-CDs / AgMOF / GCE; the prepared electrochemiluminescence sensor was named N-CDs / AgMOF / GCE;

[0117] Application method of an electrochemiluminescence sensor for detecting trilobatin:

[0118] N-CDs / AgMOF / GCE was used as the working electrode, a platinum wire electrode was used as the auxiliary electrode, and Ag / AgCl was used as the reference electrode, and the electrochemiluminescence intensity of the modified electrode before and after detecting trilobatin was tested by cyclic voltammetry scanning (electrochemical window: -1.8 V-0 V; photomultiplier high voltage: 800 V; scan rate: 0.1 V / s) in a three-electrode system;

[0119] The specific application method is the same as that in Example 1, and the results of the sensor detecting trilobatin in actual samples are shown in Table 1.

[0120] Preparation method and application method of an electrochemiluminescence sensor for detecting trilobatin.

[0121] Preparation method of an electrochemiluminescence sensor for detecting trilobatin:

[0122] (1) Preparation method of CuMOF@N-CDs:

[0123] The preparation method of the N-CDs is the same as that of S1 in step (1) of Example 1;

[0124] The preparation method of the CuMOF@N-CDs is as follows: 0.25 g of 1,3,5-benzenetricarboxylic acid is dissolved in 10 mL of ethanol to obtain solution A; 0.25 g of copper nitrate is dissolved in 10 mL of deionized water to obtain solution B; solution A and solution B are mixed, 5 mg of prepared N-CDs powder is added, and stirring is performed at 25 DEG C for 1.5 h; after the reaction is completed, centrifugation is performed, and ethanol washing and vacuum drying at 60 DEG C for 12 h are performed to obtain CuMOF@N-CDs;

[0125] The preparation method of the CuMOF@N-CDs / GCE is as follows:

[0126] The preparation method of the CuMOF@N-CDs / GCE is the same as that of step (2) of Example 1, wherein the dispersion solution taken by the microsyringe is a 1 mg / mL CuMOF@N-CDs DMF dispersion solution;

[0127] An application method of an electrochemiluminescence sensor for detecting triflavin;

[0128] CuMOF@N-CDs / GCE is used as a working electrode, a platinum wire electrode is used as an auxiliary electrode, and Ag / AgCl is used as a reference electrode; in a three-electrode system, the electrochemiluminescence intensity before and after the triflavin is detected by the modified electrode is tested through cyclic voltammetry scanning (an electrochemical window: -1.8 V to 0 V; a photomultiplier high voltage: 800 V; and a scanning speed: 0.1 V / s).

[0129] The specific application method is the same as that of Example 1, and the results of the triflavin detected by the sensor in actual samples are shown in Table 1.

[0130] Table 1 shows the detection results of the leaf samples of L. polystachyus.

[0131]

[0132]

[0133] As shown in Table 1, the electrochemiluminescence sensor based on the AgMOF@N-CDs / GCE has a standard addition recovery rate of 95.78% to 101.81% for detecting triflavin in the leaf samples of L. polystachyus, and the relative standard deviation is less than 5%, indicating that the detection effect is good. According to the above experimental results, it can be obviously observed that the triflavin in the leaf samples of L. polystachyus cannot be detected after the AgMOF@N-CDs composite material prepared in the mass ratio range of 1,3,5-benzenetricarboxylic acid, silver nitrate and N-CDs is not used and the sensor element is assembled, and therefore the electrochemiluminescence sensor constructed in the application can be used for sensitively and selectively detecting triflavin in the leaf samples of L. polystachyus.

[0134] Selective detection: a selective application method of an electrochemiluminescence sensor for detecting trilobatin.

[0135] A selective application method of an electrochemiluminescence sensor for detecting trilobatin:

[0136] AgMOF@N-CDs / GCE is used as a working electrode, a platinum wire electrode is used as an auxiliary electrode, Ag / AgCl is used as a reference electrode, 1*10 -4 M trilobatin is used as a control, 50 times of glucose (Glu), sucralose (Suc), ascorbic acid (AA), 100 times of Na + , K + , Cl - are selected as interference substances, and the electrochemiluminescence intensity of the modified electrode in an electrolyte containing trilobatin and interference substances is tested through cyclic voltammetry scanning (an electrochemical window: -1.8V-0V; a photomultiplier high voltage: 800V; a scanning speed: 0.1V / s), and the results are shown in Figure 7 Compared with the change value of the electrochemiluminescence detected without interference substances, the change value of the electrochemiluminescence detected with interference substances has no obvious difference, which indicates that the introduction of each interference substance has no obvious influence on the detection of trilobatin, that is, the AgMOF@N-CDs / GCE electrochemiluminescence sensor has good selectivity for detecting trilobatin.

[0137] Based on the AgMOF@N-CDs composite material modified glassy carbon electrode, the electrochemiluminescence sensor is constructed, when there is a small amount of trilobatin in a detection liquid, the electrochemiluminescence signal of the AgMOF@N-CDs / GCE has an obvious reduction phenomenon. It is found through research that the change value of the electrochemiluminescence intensity of the AgMOF@N-CDs / GCE electrochemiluminescence sensor for detecting trilobatin has a good linear relationship with the logarithm of the trilobatin concentration. The electrochemiluminescence method used in the present application has the advantages of simple operation, high sensitivity, fast response speed, wide linear range, low detection limit and good selectivity, and lays a foundation for subsequent design and development of the electrochemiluminescence sensor for sensitive, selective and quantitative detection of trilobatin.

[0138] The above description is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above, it is not intended to limit the present application. Any skilled person in the art can make some changes or modifications to the above disclosed technical content without departing from the technical solution range of the present application, and any simple modification, equivalent change and modification of the above embodiments based on the technical essence of the present application are still within the scope of the technical solution of the present application.

Claims

1. An electrochemiluminescence sensor for specifically detecting trilobatin, characterized in that, The electrochemiluminescence sensor is AgMOF@N-CDs / GCE; Preparation of AgMOF@N-CDs: 1,3,5-benzene tricarboxylic acid is dissolved in ethanol to obtain solution A; silver nitrate is dissolved in deionized water to obtain solution B; after mixing solution A and solution B, N-CDs is added, stirring reaction is carried out, after the reaction is completed, centrifugation, washing, drying, AgMOF@N-CDs is obtained; wherein stirring reaction is stirring reaction at 25 ℃ for 0.5-5 h; The mass ratio of 1,3,5-benzene tricarboxylic acid, silver nitrate and N-CDs is 100:100:1-10:10:1; The preparation method of N-CDs is as follows: urea and citric acid are dissolved in deionized water to obtain a mixed solution, which is transferred to a reaction kettle, reacted at 180 ℃, cooled to room temperature after the reaction is completed, centrifuged, purified by dialysis, and then freeze-dried to obtain N-CDs; wherein the mass ratio of urea to citric acid is 1:1-1:6, and the reaction time is 1-8 h.

2. The electrochemiluminescence sensor for specifically detecting trilobatin according to claim 1, characterized in that, The AgMOF@N-CDs dispersion liquid is modified on the surface of the pretreated glassy carbon electrode, dried under an infrared lamp, and AgMOF@N-CDs / GCE is obtained; the concentration of the AgMOF@N-CDs dispersion liquid is 0.5-3.0 mg / mL.

3. The use of the electrochemiluminescent sensor for specific detection of trilobatin according to claim 1, characterized in that: In a three-electrode system, AgMOF@N-CDs / GCE is used as a working electrode, a platinum wire electrode is used as an auxiliary electrode, and Ag / AgCl is used as a reference electrode, the ECL intensity of different concentrations of trilostane is detected by electrochemiluminescence method, so as to realize specific detection and quantitative analysis of trilostane.

4. The method of using the electrochemiluminescent sensor for specific detection of trifolin according to claim 3, characterized in that: The specific steps are as follows: A1. Preparation of standard solution containing different concentrations of trilostane: A stock solution of triptolide was prepared at a concentration of 1 x 10 -3 M in 0.1 M PBS buffer solution at pH 7.0 containing 0.05 M potassium persulfate, and a series of different concentrations of triptolide standard solutions were diluted, with a concentration range of 1 x 10 -7 ~1 x 10 -3 M. A2. Drawing of standard curve: AgMOF@N-CDs / GCE is used as a working electrode, a platinum wire electrode is used as an auxiliary electrode, and Ag / AgCl is used as a reference electrode to form a three-electrode system, 0.1 mol / L PBS buffer solution containing 0.05 mol / L K2S2O8 with pH 7.0 is used as a blank solution to detect electrochemiluminescence intensity, then it is placed in a series of different concentrations of trilostane standard solution prepared in step A1, cyclic voltammetry scanning is carried out, electrochemiluminescence intensity-time curve is recorded, linear relationship between the difference of luminescence intensity before and after the sensor detects trilostane and the logarithmic value of trilostane concentration is established, and the corresponding linear regression equation is obtained; A3. Actual sample detection: The solution containing trilostane is diluted with 0.1 mol / L PBS buffer solution containing 0.05 mol / L K2S2O8 with pH 7.0 to obtain a sample to be tested, electrochemiluminescence test is carried out on trilostane in the sample to be tested by standard addition method, and the concentration of trilostane in the sample to be tested is calculated according to the linear regression equation obtained in A2.

5. The method of using the electrochemiluminescent sensor for specific detection of trifolin according to claim 4, characterized in that, The linear range of electrochemiluminescence sensor for detecting trioside was 1 x 10 -7 mol / L; the lowest detection limit was 6.0 x 10 -3 mol / L. -8 mol / L; the lowest detection limit was 6.0 x 10 -3 mol / L.

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