An electrochemical detection method for dopamine

Abstract

This invention discloses an electrochemical detection method for dopamine, belonging to the field of analytical technology. The method involves loading SnS2 quantum dots onto a Zn-MOF and modifying it onto an electrode. Subsequently, gold nanoparticles and single chains containing thiol-containing dopamine aptamers are sequentially immobilized onto the electrode, forming an Apt / AuNPs / SnS2QDs@Zn-MOF / GCE composite electrode ("on" state). This significantly enhances the electrochemical signal. Based on the specific recognition between dopamine and the aptamer chain, the large cavity of the Zn-MOF encapsulates the SnS2 quantum dots with excellent electrochemical properties, achieving electrochemical signal amplification. When the target analyte, dopamine, is present, it quenches the ECL signal, resulting in a significant decrease in the electrochemical signal ("off" state). This establishes a linear relationship between the change in electrochemical signal and the dopamine concentration, achieving highly sensitive and selective detection of dopamine.

Description

Technical Field

[0001] This invention relates to a method for detecting dopamine, specifically an electrochemical method for detecting dopamine, belonging to the field of analytical detection technology. Background Technology

[0002] Dopamine, a catecholamine neurotransmitter, plays a crucial role in numerous physiological processes and influences various cognitive functions, including motivation, behavior, learning, and memory. Its clinical levels in human body fluids are extremely low, with a normal concentration range of 10. -8 Up to 10 -6 Moles per liter. As a neurotransmitter, dopamine plays a role in the brain and central nervous system (CNS), and disorders of these systems are associated with a variety of diseases, including schizophrenia, depression, and Parkinson's disease. Therefore, developing a simple and sensitive method to quantify dopamine levels is crucial, as it is essential for diagnostic purposes and research on related diseases.

[0003] Various technologies and methods have been developed for the quantitative analysis of dopamine, including electrochemical methods, fluorescence methods, chromatography, colorimetry, and even capillary electrophoresis. However, each method has its limitations, including complexity, high cost, stringent equipment requirements, and unstable results.

[0004] Compared to traditional dopamine detection methods, electrochemiluminescence (ECL) technology offers several unique advantages, such as eliminating the need for an excitation light source, high cost-effectiveness, and low background signal. ECL technology has been widely applied in medical diagnostics and environmental monitoring. Its ECL signal originates from electron transfer between electroactive substances on the electrode surface. For example, the literature (“Ultrasensitive electrochemiluminescence biosensor for dopamine based on ZnSe, grapheneoxide@multi-walled carbon nanotube and Ru(bpy)3”) 2+ L. Tian et al., Sensors and Actuators B: Chemical, 286 (2019) 266-271., proposed a method based on ZnSe, graphene-walled carbon nanotubes, and Ru(bpy)3. 2+ A high-sensitivity electrochemiluminescence biosensor for dopamine detection has been developed, but this method has low accuracy and is complex to operate. To date, there are no reports on constructing an ECL biosensor for dopamine determination using a technique combining Zn-MOF with SnS2 QDs for signal amplification. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide an electrochemical detection method for dopamine. This method is not intended for the diagnosis and treatment of diseases, but rather to overcome the deficiencies and defects of existing dopamine detection methods. The method leverages the excellent ECL properties of SnS2 quantum dots and the large cavity characteristics of Zn-MOF, combining the two to form a signal-amplified SnS2QDs@Zn-MOF. Simultaneously, it utilizes the dopamine quenching effect to form an "ON-OFF" strategy, and employs gold nanoparticles combined with dopamine aptamer single chains to enhance dopamine selectivity, thereby achieving highly sensitive and selective electrochemical detection of dopamine.

[0006] To achieve the above-mentioned technical objectives, the present invention provides an electrochemical detection method for dopamine, comprising the following steps:

[0007] 1) SnS2 quantum dots were loaded onto Zn-MOF to obtain SnS2QDs@Zn-MOF; the SnS2QDs@Zn-MOF were dispersed in water and then dropped onto the electrode surface and dried at room temperature.

[0008] 2) Then, the gold nanoparticle dispersion and the solution containing the single chain of thiol dopamine aptamer are added dropwise to the electrode surface of step 1) and incubated for I to form an Apt / AuNPs / SnS2QDs@Zn-MOF complex on the electrode surface.

[0009] 3) The electrode modified with the Apt / AuNPs / SnS2QDs@Zn-MOF complex was subjected to ECL testing in a PBS solution containing K2S2O8 to obtain the ECL intensity response value;

[0010] 4) A series of standard dopamine solutions of different concentrations were added to the electrode surface modified with Apt / AuNPs / SnS2QDs@Zn-MOF composite and incubated for II. Then, ECL testing was performed according to step 3) to obtain a series of ECL intensity response values ​​and to construct a standard curve between dopamine concentration and ECL intensity response values.

[0011] 5) Replace the standard dopamine solution in step 4) with the dopamine solution to be tested for ECL testing, obtain the corresponding ECL intensity response value, and calculate the concentration of the dopamine solution to be tested according to the standard curve.

[0012] The key to this invention lies in constructing a biosensor with electrochemical signal response to achieve highly sensitive and selective electrochemical detection of dopamine. First, a SnS2QDs@Zn-MOF composite with significantly enhanced photoelectric signal was synthesized by encapsulating tin disulfide quantum dots (SnS2QDs) into a zinc-based metal-organic framework (Zn-MOF), thereby significantly enhancing photocurrent intensity and improving detection sensitivity. This SnS2QDs@Zn-MOF composite was then modified onto the surface of a glassy carbon electrode (GCE). Next, gold nanoparticles (AuNPs) were added to the SnS2QDs@Zn-MOF-coated electrode, as the gold atoms on their surface can bind to single chains containing thiol-containing dopamine aptamers by forming Au-S bonds. Finally, the single chains containing thiol-containing dopamine aptamers were bound to the surface of the AuNPs, utilizing the dopamine aptamer to improve selectivity for dopamine, thus constructing an aptamer sensor. As expected, SnS2QDs@Zn-MOF / S2O8 2- The system exhibits a good electrochemiluminescence (ECL) response and selectivity to dopamine (DA). In the presence of dopamine, the binding of dopamine to the aptamer leads to the activation of SnS2QDs@Zn-MOF / S2O8. 2- The system's ECL signal drops sharply, and since the ECL intensity and the logarithm of dopamine concentration have a linear relationship within a certain range, electrochemiluminescence detection of dopamine can be achieved.

[0013] As a preferred embodiment, the SnS2QDs@Zn-MOF is prepared by the following method: Zn-MOF is ultrasonically dispersed in water, then SnS2 quantum dots are added, and the mixture is ultrasonically treated for 5-15 minutes, stirred for 6-18 hours, centrifuged, and dried to obtain the product. A specific preparation method for SnS2QDs@Zn-MOF is as follows: Zn-MOF powder is dissolved in water, ultrasonically treated for 10 minutes, then SnS2QDs solution is added to the above solution, ultrasonicated for 10 minutes, magnetically stirred overnight, and finally, the product is centrifuged, washed three times with deionized water, and dried overnight at 60°C. The present invention synthesizes SnS2QDs@Zn-MOF nanocomposites via Zn-MOF. The synthesized Zn-MOF has a typical flower-like structure and a large specific surface area, which is more conducive to encapsulating more SnS2QDs. Compared with the photoelectric signal of Zn-MOF alone, the photoelectric signal of SnS2QDs@Zn-MOF composite is significantly enhanced. This is because Zn-MOF has many large cavities that can load SnS2 quantum dots with excellent optical properties, thereby significantly improving photocurrent intensity and detection sensitivity.

[0014] As a preferred embodiment, the SnS2 quantum dots are prepared by dissolving SnCl4·5H2O and cysteine ​​in water to form a precursor solution. This precursor solution is then transferred to a high-pressure reactor for hydrothermal reaction. As a preferred embodiment, the hydrothermal reaction conditions are: reaction at 160℃~200℃ for 4~8 hours. For example, a method for preparing SnS2 quantum dots involves adding 2.1g SnCl4·5H2O and 2.423g cysteine ​​to 25mL H2O to form a precursor solution. The mixture is then placed in a 50mL Teflon-lined stainless steel autoclave and heated at 180℃ for 6 hours. After the mixture cools naturally to room temperature, the reaction residue is removed by centrifugation, yielding a yellow supernatant. SnS2 quantum dots are nanoscale in size and exhibit good optical properties, significantly enhancing the photoelectric signal of Zn-MOF.

[0015] As a preferred embodiment, the Zn-MOF is prepared by the following method: A zinc acetate aqueous solution and a K4PTC aqueous solution are mixed and reacted in the dark until an orange precipitate forms. The precipitate is then centrifuged, washed, and dried to obtain Zn-MOF. Another method for preparing Zn-MOF is to mix a zinc acetate aqueous solution and a K4PTC aqueous solution and allow them to react in the dark for several days until an orange precipitate is obtained. After centrifugation, washing with deionized water, and freeze-drying, the orange powder is designated as Zn-MOF. The Zn-MOF prepared by this method exhibits a unique flower-like structure with many large cavities, enabling better loading of SnS2 quantum dots.

[0016] As a preferred embodiment, the concentration of gold nanoparticles in the gold nanoparticle dispersion is 0.5–1.5 mM. The concentration of the single-chain thiol-dopamine aptamer in the single-chain thiol-dopamine aptamer solution is 4–6 μM. The drop volumes of the gold nanoparticle dispersion and the single-chain thiol-dopamine aptamer solution on the electrode surface are 8–12 μL and 8–12 μL, respectively. The concentration of the single-chain thiol-dopamine aptamer directly affects the ECL intensity. At an appropriate concentration of the single-chain thiol-dopamine aptamer, the gold nanoparticles bind an appropriate amount of the single-chain thiol-dopamine aptamer, enabling the composite electrode to achieve the most stable signal value.

[0017] As a preferred embodiment, the incubation conditions for step I are: a reaction at 30–40°C for 0.5–1.5 hours. Incubation I primarily involves binding the single chain of the thiol-containing dopamine aptamer to the gold nanoparticles. The gold nanoparticles act as a co-reaction accelerator.

[0018] As a preferred embodiment, the concentration of K2S2O8 in the K2S2O8-containing PBS solution is 9-12 mM, and the pH of the PBS solution is in the range of 7.0-8.0. As a more preferred embodiment, the K2S2O8-containing PBS solution is specifically a 0.1 M PBS solution containing 10 mM K2S2O8.

[0019] As a preferred embodiment, the incubation conditions II are: reacting at 30~40°C for 30~50 minutes.

[0020] As a preferred embodiment, the ECL test conditions are: a test voltage of -1.8 V to 0 V. As a more preferred embodiment, the ECL data acquisition scan rate is 300 mV / s, and the photomultiplier tube (PMT) voltage is 800 V.

[0021] The DNA sequence of the single-stranded thiol-dopaamine aptamer involved in this invention is: 5′-SH-(CH2)6-GTC TCT GTGTGC GCC AGA GAC ACT GGG GCA GAT ATG GGC CAG CAC AGA ATG AGG CCC-3′. It is a commercially available product.

[0022] The K4PTC involved in this invention is prepared by the following method: 5g of phthalic anhydride (PTCDA) is added to 100ml of potassium hydroxide aqueous solution (5g KOH), and the solution is kept at 130℃ for 12 hours. Then, the solution is added dropwise to 500ml of ethanol to obtain a yellow precipitate. The yellow precipitate is then washed several times with ethanol to remove the reducing agent OH. - It was then dried under reduced pressure at 40°C to obtain a yellow powder, denoted as K4PTC.

[0023] The gold nanoparticle dispersion of this invention is prepared by the following method: HAuCl4 solution is heated to boiling, then C6H5Na3O7·2H2O solution is rapidly added and stirred under reflux until the solution turns wine-red. Stirring and cooling are continued to obtain the gold nanoparticle dispersion. For example, the gold nanoparticles are prepared by heating 50 mL of HAuCl4 solution (1.0 mM) to boiling, then rapidly adding 5 mL of C6H5Na3O7·2H2O solution (38.8 mM) and stirring under reflux for 10 min until the solution turns wine-red. The heat source is turned off, and the mixture is stirred for 15 min and cooled to obtain the Au NPs dispersion, which is then stored at 4 °C in the dark for later use.

[0024] The SnS2QDs@Zn-MOF complex involved in this invention can significantly improve ECL signal intensity. The synthesis method of the SnS2QDs@Zn-MOF complex is as follows: Zn-MOF powder is dissolved in H2O and sonicated for 10 min. Then, a SnS2QDs (SnS2 quantum dots) solution is added to the above solution, sonicated for 10 min, and magnetically stirred overnight. Finally, the product is centrifuged, washed three times with deionized water, and dried overnight at 60°C.

[0025] The preparation method of SnS2QDs involved in this invention is as follows: 2.1g SnCl4·5H2O and 2.423g cysteine ​​are added to 25mL H2O to form a precursor solution. Then, the mixture is placed in a 50mL Teflon-lined stainless steel autoclave and heated at 180°C for 6 hours. After the mixture cools naturally to room temperature, the reaction residue is removed by centrifugation to obtain a yellow supernatant.

[0026] This invention quenches the ECL signal by binding the target substance (dopamine) to DA-Apt, resulting in a decrease in ECL intensity. The higher the dopamine concentration, the weaker the ECL intensity. The ECL intensity and the logarithm of the dopamine concentration have a linear relationship within a certain range, thereby quantifying the target substance dopamine.

[0027] The electrochemical detection method for photodopamine provided by this invention includes the following specific steps:

[0028] (1) Construction of electrochemical biosensor: First, a glassy carbon electrode (GCE, 3 mm in diameter) was polished with 0.3 and 0.05 μm Al2O3 powders to achieve a mirror-like interface. Then, the electrode was ultrasonically treated in ultrapure water and ethanol, and finally thoroughly dried in a nitrogen atmosphere. Subsequently, 10 μL of SnS2@Zn-MOF was first modified onto the surface of the GCE (5 mg / mL), and then 10 μL of freshly prepared gold nanoparticles were dropped onto the SnS2@Zn-MOF-coated electrode to obtain AuNPs / SnS2@Zn-MOF / GCE. Finally, 5 μL of dopamine aptamer (5 μM) was added dropwise to the electrode, and the aptamer was fixed by the Au-S bond formed between the aptamer and Au NPs, finally obtaining the Apt / AuNPs / SnS2@Zn-MOF composite electrode.

[0029] (2) Electrochemical detection of dopamine: 10 μL of SnS2@Zn-MOF (5 mg / mL) was added to the GCE and dried at room temperature. Then, 10 μL of AuNPs solution (1 mM) was added to the SnS2@Zn-MOF / GCE electrode, followed by the addition of 10 μL of Apt solution (5 μM) and drying before use. A three-electrode system was used, and ECL measurements were performed in PBS (pH 7.4) containing 0.1 mM K2S2O8 within a voltage range of -2.0 V to 0 V. ECL data were acquired using a photomultiplier tube (PMT) at a scan rate of 300 mV / s and a voltage of 800 V. Dopamine quenches the ECL signal, leading to a decrease in ECL intensity. The higher the dopamine concentration, the weaker the ECL intensity. The ECL intensity shows a linear relationship with the logarithm of the dopamine concentration within a certain range, thus allowing for the quantification of the target analyte, dopamine.

[0030] The specific preparation method of the SnS2QDs@Zn-MOF dispersion of the present invention is as follows: 5 mg of SnS2QDs@Zn-MOF powder is ultrasonically dispersed in 1 mL of ultrapure water.

[0031] Compared with the prior art, the technical solution of the present invention brings the following beneficial technical effects:

[0032] 1) This invention uses K4PTC to prepare flower-shaped Zn-MOF materials with many large cavities, which are effectively loaded with SnS2 quantum dots to form SnS2QDs@Zn-MOF composites. SnS2 quantum dots themselves are excellent optoelectronic materials. When loaded onto Zn-MOF, they further improve the utilization rate of ECL emitters. Thus, the combination of the two can significantly improve the photocurrent intensity.

[0033] 2) This invention achieves highly selective DA capture through the specific recognition of DA and aptamer single chains. It utilizes the quenching effect of dopamine to directly reduce the electrochemical signal of SnS2QDs@Zn-MOF with high ECL. The relationship between Mal concentration and ECL signal is constructed by showing that the higher the Mal concentration, the weaker the ECL intensity.

[0034] 3) This invention achieves highly sensitive ECL detection of DA by combining the excellent ECL characteristics of SnS2QDs@Zn-MOF2 with the quenching effect of DA.

[0035] 4) The signal amplification electrochemiluminescence sensing strategy for DA constructed in this invention has a good linear relationship between ECL intensity and the logarithm of target concentration in the concentration range of 0.0001~100μM, and has the advantages of wide linear range and low detection line. Attached Figure Description

[0036] Figure 1This is a schematic diagram illustrating the principle of electrochemiluminescence detection of dopamine in this invention.

[0037] Figure 2 In the image, A and B are scanning electron microscope (SEM) images of Zn-MOF; C and D are scanning electron microscope (SEM) images of SnS2QDs@Zn-MOF.

[0038] Figure 3 In the diagram, A represents the energy spectrum of the Zn-MOF material; B represents the energy spectrum of the SnS2QDs@Zn-MOF composite.

[0039] Figure 4 The results of the test on the standard sample in Example 1 are as follows: A: The concentration of the target substance detected in Example 1 and the corresponding photocurrent response curve; B: The logarithmic linear graph of the photocurrent response value and the concentration of the target substance detected in Example 1; C: The results of the selectivity test in Example 1.

[0040] Figure 5 In Figure A, the curve showing the relationship between the concentration of K2S2O8 in the PBS solution containing K2S2O8 and the ECL signal is shown; in Figure B, the curve showing the relationship between the pH value of the PBS solution containing K2S2O8 and the ECL signal is shown; in Figure C, the curve showing the relationship between the concentration of the aptamer and the ECL signal is shown; and in Figure D, the curve showing the relationship between the incubation time of the composite electrode and DA and the ECL signal is shown. Detailed Implementation

[0041] The following detailed description of the invention is provided through specific implementation examples, but these examples should not be construed as limiting the scope of protection of the claims.

[0042] Condition optimization experiment: To obtain the best performance analysis of this method, several important experimental conditions were optimized (see Example 1 for specific operation steps).

[0043] (1) Investigate the effect of K2S2O8 concentration on ECL intensity, see details. Figure 5 ECL response curves for K₂S₂O₈ concentrations in the range of 2–12 mM. The optimal signal value was found at a concentration of 10 mM.

[0044] (2) Investigating the effect of pH on ECL intensity: The signal was measured in the pH range of 5.0 to 9.0. The specific results are as follows: Figure 5 A: ECL response curves for PBS solutions with pH range of 5.0 to 9.0, showing that the signal value reaches its optimal value at pH 7.4.

[0045] (3) Investigate the effect of aptamer concentration on ECL intensity, see details below. Figure 5 The ECL response curves for C:K₂S₂O₈ concentrations in the range of 0–10 μM were obtained. The signal value was found to be most stable and optimal at a concentration of 5 μM.

[0046] (4) The effect of the reaction time for dopamine capture on ECL intensity within the range of 0–50 min was investigated. See details below. Figure 5 The effect of the reaction time for dopamine capture on ECL intensity within the range of 0-50 min was investigated, and the optimal reaction time was found to be 40 min.

[0047] The following examples are all performed under optimal conditions:

[0048] Example 1

[0049] (1) Heat 50 mL of HAuCl4 solution (1.0 mM) to boiling, then quickly add 5 mL of C6H5Na3O7·2H2O solution (38.8 mM) and stir under reflux for 10 min until the solution turns wine red. Turn off the heat source, stir for 15 min, cool to obtain Au NPs dispersion, and store at 4 °C in the dark for later use.

[0050] (2) SnS2 QDs were prepared according to existing literature. In short, SnCl4·5H2O (6.0 mM) and L-cysteine ​​(20 mM) were added to 25 mL of water, and the reaction solution was heated at 180°C for 6 h in a 50 mL Teflon-lined stainless steel autoclave. After natural cooling to room temperature, the reaction mixture was centrifuged to remove the reactant residues, yielding a yellow supernatant.

[0051] (3) Dissolve 25 mg of Zn-MOF powder in 5 mL of water and sonicate it for 6 hours. Then, add 5 mL of the SnS2QD solution prepared in step (2) to the above reaction solution and sonicate it for 10 minutes. Then, stir it magnetically overnight. Then, separate the mixture by centrifugation, wash it three times with deionized water, and dry it overnight at 60°C.

[0052] (4) Prepare DA-apt solutions of the appropriate concentrations using Tris-HCl buffer solution (specific preparation methods and dosages are indicated on the purchased test tubes). Prepare 10 μL of dopamine at different concentrations (0.0001~100 μM).

[0053] (5) The glassy carbon electrode (GCE, 3 mm in diameter) was polished to a mirror-like surface using 0.3 μm and 0.05 μm Al2O3 powders, then ultrasonically treated in ultrapure water and ethanol, and finally dried in a N2 atmosphere. First, 10 μL of SnS2QDs@Zn-MOF prepared in step (3) was applied to the surface of the GCE and dried at room temperature to obtain SnS2QDs@Zn-MOF / GCE. Subsequently, 10 μL of gold nanoparticles prepared in step (1) were dropped onto the SnS2QDs@Zn-MOF coated electrode to obtain AuNPs / SnS2QDs@Zn-MOF / GCE. Finally, 5 μL of a thiol-containing dopamine aptamer (5 μM) was dropped onto the electrode to fix the aptamer by forming Au-S bonds between the aptamer and AuNPs.

[0054] (6) 10 μL of dopamine at different concentrations was dropped onto the electrode and the reaction was maintained at 37°C for 40 minutes to finally obtain the DA / AuNPs / SnS2QDs@Zn-MOF / GCE electrode.

[0055] (7) ECL measurements were performed in a PBS (pH 7.4) solution containing 10 mM K2S2O8 within a voltage range of -1.8 V to 0 V. ECL data were acquired using a photomultiplier tube (PMT) at a scan rate of 300 mV / s and a voltage of 800 V. The higher the DA concentration, the weaker the ECL intensity, and there is a definite relationship between ECL intensity and DA concentration, thus achieving sensitive detection of DA. The above detection was performed using the test solution instead of the DA standard solution, and the concentration results were obtained through a standard curve.

[0056] Example 1: DNA sequence containing thiol dopamine aptamer [purchased from Sangon Biotech (Shanghai) Co., Ltd.] is as follows:

[0057]

[0058] Figure 1 This is a schematic diagram illustrating the principle and process of electrochemiluminescence detection of dopamine based on AuNPs / SnS2QDs@Zn-MOF / GCE electrode involved in this invention. Figure 2 The images show scanning electron microscope (SEM) images of Zn-MOF and SnS2 QDs@Zn-MOF materials. The SEM images show that the synthesized Zn-MOF exhibits a uniform nanoflower morphology with an average diameter of about 18 μm. When SnS2 is loaded onto Zn-MOF, a slight increase in the diameter of the material is observed. Figure 3 The EDS plot shows the coexistence of C, O, Zn, Sn, and S elements in SnS2QDs@Zn-MOF nanospheres. Figure 4 The test results of the standard sample in Example 1 are as follows: Figure 4B shows that within the dopamine concentration range of 0.0001–100 μM, the ECL intensity exhibits a good linear relationship with the logarithm of the target analyte concentration. Furthermore, to demonstrate the practical applicability of this invention, the specificity and selectivity of the method for dopamine were investigated, with ascorbic acid (AA), glucose (GLU), and glutathione (GSH) selected as interfering agents. Experimental results show that the ECL intensity of high-concentration interfering agents is not significantly different from that of the blank sample. Therefore, this method for DA detection demonstrates good selectivity and specificity. Figure 4 C).

[0059] The above description is only the preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention shall be covered by the present invention.

Claims

1. An electrochemical detection method for dopamine, characterized in that: Includes the following steps: 1) SnS2 quantum dots were loaded onto Zn-MOF to obtain SnS2QDs@Zn-MOF; the SnS2QDs@Zn-MOF were dispersed in water and then dropped onto the electrode surface and dried at room temperature. 2) Then, the gold nanoparticle dispersion and the solution containing the single chain of thiol dopamine aptamer are added dropwise to the electrode surface of step 1) and incubated for I to form an Apt / AuNPs / SnS2QDs@Zn-MOF complex on the electrode surface. 3) The electrode modified with the Apt / AuNPs / SnS2QDs@Zn-MOF complex was subjected to ECL testing in a PBS solution containing K2S2O8 to obtain the ECL intensity response value; 4) A series of standard dopamine solutions of different concentrations were added to the electrode surface modified with Apt / AuNPs / SnS2QDs@Zn-MOF composite and incubated for II. Then, ECL testing was performed according to step 3) to obtain a series of ECL intensity response values ​​and to construct a standard curve between dopamine concentration and ECL intensity response values. 5) Replace the standard dopamine solution in step 4) with the dopamine solution to be tested for ECL testing, obtain the corresponding ECL intensity response value, and calculate the concentration of the dopamine solution to be tested according to the standard curve.

2. The electrochemical detection method for dopamine according to claim 1, characterized in that: The SnS2QDs@Zn-MOF was prepared by the following method: Zn-MOF was ultrasonically dispersed in water, SnS2 quantum dots were added, ultrasonic treatment was continued for 5-15 min, and then stirred for 6-18 h. After centrifugation and drying, the product was obtained.

3. The electrochemical detection method for dopamine according to claim 1 or 2, characterized in that: The SnS2 quantum dots were prepared by dissolving SnCl4·5H2O and cysteine ​​in water to form a precursor solution, which was then transferred into a high-pressure reactor for hydrothermal reaction to obtain the product.

4. The electrochemical detection method for dopamine according to claim 3, characterized in that: The hydrothermal reaction conditions are: reaction at 160℃~200℃ for 4~8 hours.

5. The electrochemical detection method for dopamine according to claim 1, characterized in that: The Zn-MOF was prepared by mixing an aqueous solution of zinc acetate and an aqueous solution of K4PTC in the dark and reacting them until an orange precipitate was formed. After centrifugation, washing and drying, Zn-MOF was obtained.

6. The electrochemical detection method for dopamine according to claim 1, characterized in that: The concentration of gold nanoparticles in the gold nanoparticle dispersion is 0.5~1.5mM; The concentration of the single chain containing the thiol dopamine aptamer in the solution is 4~6 μM; The drop volumes of the gold nanoparticle dispersion and the single-chain solution containing thiol dopamine aptamer on the electrode surface are 8~12 μL and 8~12 μL, respectively.

7. The electrochemical detection method for dopamine according to claim 1 or 6, characterized in that: The incubation conditions for I are: reaction at 30~40℃ for 0.5~1.5 hours.

8. The electrochemical detection method for dopamine according to claim 1, characterized in that: The concentration of K2S2O8 in the PBS solution containing K2S2O8 is 9-12 mM, and the pH of the PBS solution is in the range of 7.0-8.

0.

9. The electrochemical detection method for dopamine according to claim 1, characterized in that: The conditions for incubation II are: reaction at 30~40℃ for 30~50 minutes.

10. The electrochemical detection method for dopamine according to claim 1, characterized in that: The conditions for the ECL test are: the test voltage is -1.8 V to 0 V.

Images