A preparation method and a detection method of an electrochemical emission sensor for detecting di(2-ethylhexyl) phthalate

Abstract

The application relates to the field of electrochemiluminescence detection, in particular to a preparation method and a detection method of an electrochemiluminescence sensor for detecting di(2-ethylhexyl) phthalate. Technical points are as follows: the electrochemiluminescence aptamer sensor is formed by loading carboxylated ligands on the surface of a Zr-MOF / GDY composite material modified glassy carbon electrode; the Zr-MOF / GDY composite material is formed by electrostatic interaction between Zr-MOF and GDY; and the carboxylated aptamer is an aptamer containing a base sequence of 5'-GGGTAGGGCGGGAAGTTACTGTCTTACTGTC GTA-3'. The recovery effect of DEHP on the ECL signal intensity of the electrochemiluminescence aptamer sensor of the GDY and Zr-MOF composite material is used to realize the detection of DEHP, and the detection method is simple in operation, good in selectivity and high in sensitivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrochemiluminescence detection, and in particular to a preparation method and detection method of an electrochemiluminescence sensor for detecting di(2-ethylhexyl) phthalate. BACKGROUND

[0002] Di(2-ethylhexyl) phthalate (DEHP) is the most widely used plasticizer in the production of plastic products, with an annual production of about 1 million to 4 million tons. Since DEHP molecules are connected to plastic polymers through pure physical bonds rather than chemical bonds, they are released from microplastics into water and soil environments after weathering and photolysis, and further enter the human body through the food chain. As an endocrine disruptor, DEHP can cause endocrine disorders in the human body, induce cancer or cause reproductive toxicity. It has been listed as an environmental priority pollutant by the United States Environmental Protection Agency (EPA) and the Ministry of Ecology and Environment of the People's Republic of China. In order to ensure public health and safety, it is urgent to establish a rapid and convenient detection method to monitor DEHP in the water environment.

[0003] The currently used DEHP detection methods include gas chromatography and high performance liquid chromatography (GC-HPLC), gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry, and gas chromatography flame ionization detection (GC-FID), which require complex pretreatment steps and professional technicians. The detection method is complicated and cannot quickly obtain the detection result.

[0004] In view of the defects of the existing detection methods, the present application is based on the rich experience and professional knowledge of the inventors in such materials for many years, combined with theoretical analysis, research and innovation, to develop a preparation method and detection method of an electrochemiluminescence sensor for detecting di(2-ethylhexyl) phthalate. SUMMARY

[0005] The purpose of the present application is to develop a preparation method of an electrochemiluminescence sensor for detecting di(2-ethylhexyl) phthalate (DEHP), which utilizes Zr-MOF / GDY nanocomposite to modify the surface of a glassy carbon electrode, obtains a Zr-MOF / GDY / GCE modified electrode, and improves the detection sensitivity by high signal-to-noise ratio, so as to achieve the purpose of trace detection of the target substance, significantly improve the sensitivity and stability of the electrochemiluminescence detection of di(2-ethylhexyl) phthalate (DEHP), and have the advantages of high sensitivity, low background, easy control, strong specificity, and short detection time.

[0006] The above technical purpose of the present application is achieved by the following technical scheme:

[0007] The application provides a preparation method of an electrochemiluminescence sensor for detecting di(2-ethylhexyl) phthalate.

[0008] The Zr-MOF / GDY composite material is formed by electrostatic interaction between Zr-MOF and GDY.

[0009] The carboxylated aptamer has a base sequence of 5'-COOH-ACGCATAGGGTGCGACCACATACGCCCCATGTATGTCCCTTGGTTGTGCCCTATGCGT-3'.

[0010] 5'-COOH-ACGCATAGGGTGCGACCACATACGCCCCATGTATGTCCCTTGGTTGTGCCCTATGCGT-3'.

[0011] Further, the preparation method specifically comprises the following operation steps:

[0012] GDY is dispersed in water to obtain solution 1; Zr-MOF is dispersed in DMF to obtain solution 2; solution 1 is drop-coated on the surface of a glassy carbon electrode; solution 2 is drop-coated on the surface of the GDY / glassy carbon electrode; and the Zr-MOF / GDY modified glassy carbon electrode is obtained by natural air drying; the carboxylated aptamer is loaded on the surface of the composite material Zr-MOF / GDY modified glassy carbon electrode through dehydration condensation reaction of NH2 and COOH, and the electrochemiluminescence aptamer sensor is prepared by natural air drying.

[0013] In the application, in addition to the dehydration condensation reaction of NH2 and COOH, electrostatic adsorption also exists between the carboxylated aptamer and the composite material, and the two effects load the carboxylated aptamer on the surface of the Zr-MOF / GDY composite material modified glassy carbon electrode; after incubation at room temperature for 6 hours, the electrochemiluminescence aptamer sensor (COOH-apt / Zr-MOF / GDY / GCE) for detecting DEHP is prepared.

[0014] Further, the preparation method of Zr-MOF is as follows: ZrCl4 and lauric acid are dissolved in an organic solvent, 2-amino terephthalic acid is added after ultrasonic mixing, and a solvothermal synthesis reaction is performed after ultrasonic mixing, so that Zr-MOF is obtained.

[0015] Further, the preparation method of GDY specifically comprises the following steps: a hexaethylbenzene monomer is synthesized by mixing and stirring a hexaalkyl-[(trimethylsilyl) ethyl] benzene, tetrahydrofuran (THF) solution and tetrabutylammonium fluoride; the GDY thin film is grown on the surface of a copper foil by adopting a cross-coupling reaction of the hexaethylbenzene monomer; and the GDY thin film is washed and dried to obtain GDY powder.

[0016] Further, the concentration of solution 1 and solution 2 is 1 mg / L, and the drop coating amount of the dispersion is 5 μL.

[0017] Further, the dehydration condensation reaction of NH2 and COOH is as follows: first, carboxylated aptamers are added to a Tris-HCl buffer solution containing KCl, NaCl, MgCl2 and ethylenediaminetetraacetic acid to prepare an aptamer solution with an aptamer concentration of 1-10 μM, then the aptamer solution is removed and dropped on the surface of the Zr-MOF / GDY modified glassy carbon electrode.

[0018] Further, the concentration of the aptamer in the aptamer solution is 3 μM, which can ensure better electrochemiluminescence intensity.

[0019] Further, the carboxylated aptamer is an aptamer containing the base sequence of 5'-COOH-ACGCATAGGGTGCGACCACATACGCCCCATGTATGTCCCTTGGTTGTGCCCTATGCGT-3'.

[0020] 5'-COOH-ACGCATAGGGTGCGACCACATACGCCCCATGTATGTCCCTTGGTTGTGCCCTATGCGT-3' base sequence.

[0021] The second object of the present application is to provide a detection method of an electrochemiluminescence sensor for detecting di(2-ethylhexyl) phthalate, which successfully realizes sensitive detection of DEHP through the recovery effect of the ECL signal intensity of the electrochemiluminescence aptamer sensor of the graphite yne GDY and zirconium-based metal organic framework Zr-MOF composite material.

[0022] The above technical objects of the present application are achieved by the following technical solutions:

[0023] The detection method of the electrochemiluminescence sensor for detecting di(2-ethylhexyl) phthalate provided by the present application is a three-electrode system composed of an electrochemiluminescence sensor as a working electrode, Ag / AgCl as a reference electrode, and a platinum wire electrode as a counter electrode, and the detection is completed through the generated electrochemiluminescence signal.

[0024] Specifically, the detection method comprises the following operation steps:

[0025] The COOH-apt / Zr-MOF / GDY / GCE electrochemiluminescence aptamer sensor is used as a working electrode, Ag / AgCl is used as a reference electrode, and a platinum wire electrode is used as a counter electrode to form a three-electrode system, di(2-ethylhexyl) phthalate in the sample to be measured is quantitatively captured to the surface of the sensor, and the detection is realized through the generated luminescence signal.

[0026] Further, the detection method provided by the present application is specifically operated as follows:

[0027] S1, preparation of a PBS nanobubble buffer solution containing K2S2O8;

[0028] S2, preparation of standard solutions of different concentrations of di(2-ethylhexyl) phthalate;

[0029] S3, draw a standard curve, respectively, immerse the electrochemiluminescence aptamer sensor in an equal amount of the standard solution prepared in step S2 and react for the same time, so that the electrochemiluminescence aptamer sensor binds the di(2-ethylhexyl) phthalate, DEHP / COOH-apt / Zr-MOF / GDY / GCE is obtained, then the electrochemiluminescence aptamer sensor is used as a working electrode, Ag / AgCl is used as a reference electrode, and platinum is used as a counter electrode, a three-electrode system is formed, a PBS nanobubble buffer solution containing K2S2O8 in step S1 is used as an electrolyte, cyclic voltammetry scanning is carried out, the luminescence intensity-time curve is recorded, the linear relationship between the luminescence intensity before and after the electrochemiluminescence aptamer sensor binds the di(2-ethylhexyl) phthalate and the logarithmic value of the di(2-ethylhexyl) phthalate in the di(2-ethylhexyl) phthalate standard solution is established, and a corresponding linear regression equation is obtained;

[0030] S4, detection of di(2-ethylhexyl) phthalate in the sample to be measured, without any pretreatment, an appropriate amount of bottled beverage is taken out from the container, and then the electrochemiluminescence aptamer sensor is reacted with the electrochemiluminescence aptamer sensor surface for the same time according to step S3, so that the electrochemiluminescence aptamer sensor binds the di(2-ethylhexyl) phthalate, then the electrochemiluminescence aptamer sensor is used as a working electrode, the luminescence intensity is detected by the method of step S3, and the concentration of di(2-ethylhexyl) phthalate in the sample to be measured is calculated according to the linear regression equation.

[0031] Further, the cyclic voltammetry scanning condition is that the electrochemical window range is-2.0~0V, the photomultiplier high voltage is 800V, and the scanning speed is 0.1V / s.

[0032] Further, the reaction time of the electrochemiluminescence aptamer sensor in step S3 is 20min.

[0033] In summary, the present application has the following beneficial effects:

[0034] The application designs an electrochemiluminescence aptamer sensor based on a graphite dyine GDY and zirconium-based metal organic framework Zr-MOF composite material, two materials are combined through electrostatic interaction, and high-efficiency and stable electrochemiluminescence performance can be obtained. The application makes full use of the unique advantages of aptamers and electrochemiluminescence sensors, successfully realizes sensitive detection of DEHP through the recovery effect of DEHP on the ECL signal intensity of the system, and experiments prove that the sensing platform can specifically identify the detection substance DEHP.

[0035] The detection range of the application is 1.0*10 -12 ~ 1.0*10 -4 mg / mL, the lowest detection limit is 2.53*10 -13 mg / mL, the method for detecting DEHP is simple in operation, good in selectivity, high in sensitivity, wide in detection range, and has important significance for popularizing the application of the aptamer sensor in actual detection. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The ECL response graph of the electrochemiluminescence aptamer sensor constructed in Example 1 after being combined with DEHP of different concentrations;

[0037] Figure 2 The standard curve of the difference (ΔECL) of the luminescence intensity of Example 1 before and after adding DEHP and the logarithmic value of the DEHP concentration;

[0038] Figure 3 The scanning electron microscope graph of the Zr-MOF / GDY composite material prepared in Example 1;

[0039] Figure 4 The ECL response graph of the Zr-MOF / GDY modified glassy carbon electrode with time;

[0040] Figure 5 The ECL response graph of the GDY modified glassy carbon electrode with time;

[0041] Figure 6 The ECL response graph of the Zr-MOF modified glassy carbon electrode with time;

[0042] Figure 7 The ECL response graph of the COOH-apt / Zr-MOF / GDY modified glassy carbon electrode with time. DETAILED DESCRIPTION

[0043] For further illustrating the technical means and effects adopted by the present application to achieve the predetermined object, the specific implementation, features and effects of the preparation method of an electrochemiluminescence sensor for detecting di(2-ethylhexyl) phthalate and the detection method thereof according to the present application are described in detail as follows.

[0044] In the present specific implementation, the Zr-MOF contains

[0045] The aptamer with the base sequence of 5'-COOH-ACGCATAGGGTGCGACCACATACGCCCCATGTATGTCCCTTGGTTGTGCCCTATGCGT-3' is purchased from Shengong Bioengineering (Shanghai) Co., Ltd.

[0046] The concentration of DEHP in the DEHP standard solution is (a) 1.0×10 -4 g / L, (b) 1.0×10 -5 g / L, (c) 1.0×10 -6 g / L, (d) 1.0×10 -7 g / L, (e) 1.0×10 -8 g / L, (f) 1.0×10 -9 g / L, (g) 1.0×10 -10 g / L, (h) 1.0×10 -11 g / L, and (i) 1.0×10 -12 g / L.

[0047] Example 1: A preparation method of an electrochemiluminescence sensor for detecting di(2-ethylhexyl) phthalate and a detection method thereof

[0048] Preparation of the electrochemiluminescence sensor:

[0049] S1, Preparation of Zr-MOF:

[0050] Zirconium tetrachloride (80 mg, 0.34 mmol) and lauric acid (2.4 g, 12 mmol) were dissolved in 20 mL of DMF, and the mixture was subjected to intense ultrasonic treatment at room temperature for 20 min. 2-Aminoterephthalic acid (31 mg, 0.17 mmol) was added to the above solution, and the ultrasonic treatment was continued for 5 min. The obtained uniform mixture was transferred to an autoclave for reaction at 120℃ for 12 h. The yellow precipitate was washed with DMF and ethanol for 3 times respectively, and was centrifuged, washed at 12000 rpm. Finally, it was dried under vacuum at room temperature.

[0051] S2, Preparation of GDY material:

[0052] Synthesis of hexaethylbenzene monomer by mixing hexaethyl-[(trimethylsilyl)ethyl]benzene, tetrahydrofuran (THF) solution and tetrabutylammonium fluoride (TBAF) at 8℃ and stirring for 10 min, synthesis of GDY thin film by cross-coupling reaction of hexaethylbenzene monomer under the condition of nitrogen atmosphere at 60℃ for 72 h, ultrasonic treatment and washing with acetone of the thin film, then ultrasonic treatment with hot dimethylformamide (DMF; 80℃) for 1 h, peeling off the black solid, refluxing the solid in NaOH (4M), HCl (6M) and NaOH (4M) at 100℃ for 2 h in sequence to remove residual copper and other impurities, and obtaining the product by washing with hot DMF (80℃) and hot ethanol (70℃), centrifugal collection and drying in a vacuum oven overnight to obtain GDY crystalline black powder;

[0053] S3, dispersing the Zr-MOF obtained in step S1 in DMF to obtain solution 1, dispersing GDY in ultrapure water to obtain solution 2, and the concentration of the two dispersions is 1 mg / mL;

[0054] S4, preparation of the electrochemiluminescence aptamer sensor for detecting DEHP, polishing the glassy carbon electrode into a mirror surface with polishing powder (Al2O3) on a suede, then ultrasonic cleaning with nitric acid solution, ethanol solution and ultrapure water, and drying at room temperature to obtain a pretreated glassy carbon electrode, dropping 5 μL of solution 2 prepared in step S3 on the surface of the glassy carbon electrode with a microsyringe, and naturally air-drying, then dropping 5 μL of solution 1 obtained in step S3 on the surface of the glassy carbon electrode, naturally air-drying, and modifying 5 μL of the prepared Tris-HCl buffer solution containing carboxylated aptamer, and incubating at room temperature for 6 h to obtain a COOH-apt / Zr-MOF / GDY / GCE sensor as a sensing element for electrochemiluminescence test.

[0055] In the aptamer solution, the concentration of the carboxylated aptamer is 3 μM.

[0056] Method for detecting DEHP based on the COOH-apt / Zr-MOF / GDY / GCE sensor

[0057] A1, drawing of a standard curve

[0058] The prepared electrochemiluminescence aptamer sensor was immersed in equal amounts of different concentrations of DEHP standard solution and reacted for the same time, so that the electrochemiluminescence aptamer sensor combined with DEHP, then DEHP / COOH-apt / Zr-MOF / GDY / GCE was used as the working electrode, Ag / AgCl as the reference electrode, and platinum electrode as the counter electrode to form a three-electrode system, with PBS nanobubble buffer solution containing 0.1 mol / L K2S2O8 and having a pH of 7.4 as the electrolyte, in the electrochemical window range of -2.0~0 V, the photomultiplier high voltage was 800 V, the scanning speed was 0.1 V / s, cyclic voltammetry scanning was performed, the luminescence intensity-time curve was recorded, the linear relationship between the luminescence intensity difference (ΔECL) of the electrochemiluminescence aptamer sensor before and after combining with DEHP and the logarithmic value of the DEHP concentration in the DEHP standard solution was established, and the corresponding linear regression equation was obtained; ∆ECL=12945.1099+1002.9124lgC(mg / mL), the detection range was 1.0×10 -12 ~1.0×10 -4 g / L, and the detection limit was 2.53×10 -13 mg / mL.

[0059] A2, detection of samples

[0060] 0.1 ng·L -1 DEHP was added to the river water sample, the prepared electrochemiluminescence aptamer sensor was immersed in the above solution, and the concentration of DEHP in the sample to be detected was calculated according to the linear regression equation obtained in step A1, and the results are shown in Table 1.

[0061] In this example, Zr-MOF / GDY was used as the substrate material (morphology as shown in Figure 4 ), and the electrostatic interaction between Zr-MOF and GDY was used to stably combine, which could greatly improve the electrochemiluminescence intensity of the single material, had good conductivity, good stability, and good sensor selectivity.

[0062] Comparative Example 1

[0063] Preparation of electrochemiluminescence sensor:

[0064] 5 μL of solution 1 prepared in Example 1 was removed by a micro-syringe and dropped on the surface of the pretreated glassy carbon electrode (the pretreatment method was the same as in Example 1), and a Zr-MOF / GCE chemically modified electrode was obtained. After natural air drying, 5 μL of 3 μM carboxylated aptamer was dropped on the surface of the Zr-MOF / GCE chemically modified electrode, and a COOH-apt / Zr-MOF / GCE sensor was obtained after incubation at room temperature for 6 h, which was used as a sensing element for electrochemiluminescence test.

[0065] DEHP detection based on COOH-apt / Zr-MOF / GCE sensor

[0066] A1, standard curve drawing

[0067] The COOH-apt / Zr-MOF / GCE sensor prepared above was used as a sensing element, and an equal amount of DEHP standard solution of different concentrations was modified on the surface of the sensor and reacted for 30 min. Then, the sensor was used as a working electrode, Ag / AgCl was used as a reference electrode, and platinum was used as a counter electrode to form a three-electrode system. The luminescence intensity was measured in a 0.1 mol / L PBS buffer solution containing 0.05 mol / L K2S2O8 at pH 7.4 as an electrolyte. In the electrochemical window range of -2.0-0 V, the high voltage of the photomultiplier tube was 800 V, the scanning speed was 0.1 V / s, and the cyclic voltammetry scanning was performed. The luminescence intensity-time curve was recorded, and the linear relationship between the luminescence intensity difference before and after the combination of the electrochemiluminescence aptamer sensor and DEHP and the logarithmic value of the DEHP concentration in the DEHP standard solution was established. The corresponding linear regression equation was obtained.

[0068] A2, sample detection

[0069] 0.1 ng·L -1 DEHP was added to the river water sample, and the electrochemiluminescence aptamer sensor prepared above was immersed in the above solution. The concentration of DEHP in the sample to be detected was calculated according to the linear regression equation obtained in step A1, and the results are shown in Table 1.

[0070] Comparative Example 2:

[0071] Preparation of electrochemical sensor

[0072] 5 μL of solution 2 prepared in Example 1 was removed with a microsyringe and dropped on the surface of the pretreated glassy carbon electrode (the pretreatment method was the same as in Example 1). 5 μL of 3 μM carboxylated aptamer was dropped on the surface of the GDY / GCE chemical modification electrode, and the COOH-apt / GDY / GCE sensor was obtained after natural air drying, which was used as a sensing element for electrochemiluminescence test. (The modification amount of the monomer test was kept as a single variable with the sample concentration in Example 1)

[0073] DEHP detection based on COOH-apt / GDY / GCE sensor

[0074] A1, standard curve drawing

[0075] The COOH-apt / GDY / GCE sensor prepared above was used as a sensing element, and an equal amount of DEHP standard solution of different concentrations was modified on the surface of the sensor and reacted for 30 min. Then, the sensor was used as a working electrode, Ag / AgCl was used as a reference electrode, and platinum was used as a counter electrode to form a three-electrode system. The luminescence intensity was measured in a 0.1 mol / L PBS buffer solution containing 0.1 mol / L K2S2O8 and having a pH of 7.4. The electrochemical window was -2.0-0 V, the high voltage of the photomultiplier tube was 800 V, the scanning speed was 0.1 V / s, and the cyclic voltammetry scanning was performed. The luminescence intensity-time curve was recorded, and the linear relationship between the luminescence intensity difference before and after the electrochemiluminescence sensor combined with DEHP and the logarithmic value of the DEHP concentration in the DEHP standard solution was established, and the corresponding linear regression equation was obtained.

[0076] A2, detection of samples

[0077] 0.1 ng·L -1 DEHP was added to the river water sample. The electrochemiluminescence aptamer sensor prepared was immersed in the above solution, and the concentration of DEHP in the sample to be detected was calculated according to the linear regression equation obtained in step A1. The results are shown in Table 1.

[0078] Comparative Example 3:

[0079] Preparation of COOH-apt / Zr-MOF@GDY / GCE sensor

[0080] 5 μL of solution 1 and solution 2 prepared in Example 1 were respectively taken by a microsyringe and dropped on the surface of the pretreated glassy carbon electrode (the pretreatment method was the same as that in Example 1) to obtain a Zr-MOF@GDY / GCE chemical modified electrode. After natural air drying, 5 μL of 3 μM carboxylated aptamer was dropped on the surface of the Zr-MOF@GDY / GCE chemical modified electrode, and the COOH-apt / Zr-MOF@GDY / GCE sensor was obtained after incubation at room temperature for 6 h, which was used as a sensing element for electrochemiluminescence test. (The modification amount of the monomer test was kept as a single variable with the sample concentration in Example 1.)

[0081] DEHP detection based on COOH-apt / Zr-MOF@GDY / GCE sensor

[0082] A1, preparation of standard curve

[0083] The COOH-apt / Zr-MOF@GDY / GCE sensor prepared in step A1 was immersed in an equal amount of DEHP standard solution of different concentrations and reacted for 30 min, then it was used as a working electrode, Ag / AgCl was used as a reference electrode, and platinum electrode was used as a counter electrode to form a three-electrode system, and the luminescence intensity was measured in 0.1 mol / L PBS buffer solution containing 0.1 mol / L K2S2O8 and pH 7.4. In the electrochemical window range of -2.0~0 V, the photomultiplier high voltage was 800 V, the scanning speed was 0.1 V / s, the cyclic voltammetry scanning was carried out, the luminescence intensity-time curve was recorded, the linear relationship between the luminescence intensity difference before and after the electrochemiluminescence aptamer sensor combined with DEHP and the logarithmic value of the DEHP concentration in the DEHP standard solution was established, and the corresponding linear regression equation was obtained.

[0084] A2, detection of samples

[0085] 0.1 ng·L -1 DEHP was added to the river water sample, the prepared electrochemiluminescence aptamer sensor was immersed in the above solution, and the concentration of DEHP in the sample to be detected was calculated according to the linear regression equation obtained in step A1. The results are shown in Table 1.

[0086] Table 1 Test of DEHP in a river water sample

[0087]

[0088] Note: a is the average value of three determinations

[0089] As shown in Table 1, the sample was determined in triplicate, the recovery rate was between 97% and 103%, and the relative standard deviation was less than 5%, indicating that the recovery effect was good. The above experimental results show that the sensor of the present application can be used for detecting DEHP in bottled beverages.

[0090] Based on the above verification, it can be known that the application is based on the electrochemiluminescence recovery effect of DEHP on the COOH-apt / Zr-MOF / GDY / GCE system, and a new method for rapidly and sensitively detecting DEHP is constructed. Since Zr-MOF and GDY have good electrostatic interaction, the Zr-MOF / GDY composite material with high electrochemiluminescence intensity and good stability can be formed. When there is a trace amount of DEHP, the Zr-MOF in the COOH-apt / Zr-MOF / GDY / GCE system can enrich the specific binding of the detection substance DEHP and the aptamer, change the material properties of the electrode surface, and make DEHP and COOH-apt fall off from the electrode surface together, so that the ECL signal of COOH-apt / Zr-MOF / GDY / GCE is increased. It is found through research that the enhanced value (ΔECL) of the ECL signal of the COOH-apt / Zr-MOF / GDY / GCE sensor system and the concentration of DEHP show a good linear relationship. The electrochemiluminescence method used in the application not only has the advantages of high sensitivity, fast detection speed, good selectivity and wide linear range, but also has great application potential in the quantitative analysis of DEHP in water environment.

[0091] The above is only a preferred embodiment of the application, and does not limit the application in any form. Although the application has been shown as above with a preferred embodiment, it is not intended to limit the application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content without departing from the scope of the technical solution of the application, and any simple modification, equivalent change and modification of the above embodiment according to the technical essence of the application still belong to the scope of the technical solution of the application.

Claims

1. A method for preparing an electrochemiluminescent sensor for detecting di(2-ethylhexyl) phthalate, characterized by, The electrochemiluminescence aptamer sensor is formed by loading carboxylated aptamer on the surface of a Zr-MOF / GDY composite material modified glassy carbon electrode; wherein the Zr-MOF / GDY composite material is formed by electrostatic interaction between Zr-MOF and GDY; and the carboxylated aptamer is an aptamer containing a 5'-COOH-ACGCATAGGGTGCGACCACATACGCCCCATGTATGTCCCTTGGTTGTGCCCTATGCGT-3' base sequence.

2. The method for preparing an electrochemiluminescence sensor for detecting di(2- ethylhexyl) phthalate according to claim 1, characterized in that, The method comprises the following operation steps: GDY is dispersed in water to obtain solution 1; Zr-MOF is dispersed in DMF to obtain solution 2; solution 1 is drop-coated on the surface of a glassy carbon electrode; solution 2 is drop-coated on the surface of a GDY / glassy carbon electrode; and the Zr-MOF / GDY modified glassy carbon electrode is obtained by natural air drying; The carboxylated aptamer is loaded on the surface of the Zr-MOF / GDY composite material modified glassy carbon electrode through a dehydration condensation reaction between -NH2 and -COOH, and the electrochemiluminescence aptamer sensor is obtained by natural air drying.

3. The method for preparing an electrochemiluminescent sensor for detecting di(2- ethylhexyl) phthalate according to claim 2, characterized in that, The Zr-MOF is prepared by the following method: ZrCl4 and lauric acid are dissolved in an organic solvent, ultrasonically mixed until uniform, 2-amino terephthalic acid is added, ultrasonically mixed, and then a solvothermal synthesis reaction is performed to obtain Zr-MOF.

4. The method for preparing an electrochemiluminescent sensor for detecting di(2- ethylhexyl) phthalate according to claim 2, characterized in that, The GDY is prepared by the following steps: a hexaethylbenzene monomer is synthesized by mixing and stirring a hexaalkyl-[(trimethylsilyl)ethyl]benzene, tetrahydrofuran (THF) solution and tetrabutylammonium fluoride; a GDY thin film is grown on the surface of a copper foil through a cross-coupling reaction of the hexaethylbenzene monomer; and the GDY thin film is washed and dried to obtain GDY powder.

5. The method for preparing an electrochemiluminescent sensor for detecting di(2- ethylhexyl) phthalate according to claim 2, characterized in that, The concentrations of the solution 1 and the solution 2 are both 1 mg / L, and the drop-coating amount of the dispersion is 5 μL.

6. The method for preparing an electrochemiluminescence sensor for detecting di(2- ethylhexyl) phthalate according to claim 2, characterized in that, The dehydration condensation reaction between -NH2 and -COOH is as follows: first, carboxylated aptamer is added to a Tris-HCl buffer solution containing KCl, NaCl, MgCl2 and ethylenediaminetetraacetic acid to prepare an aptamer solution with an aptamer concentration of 1-10 μM; then, the aptamer solution is removed and drop-coated on the surface of the Zr-MOF / GDY composite material modified glassy carbon electrode.

7. A method for detecting an electrochemiluminescence sensor of di(2-ethylhexyl) phthalate prepared by the method according to any one of claims 1 to 6, characterized in that, The electrochemiluminescence aptamer sensor is used as a working electrode, Ag / AgCl is used as a reference electrode, and a platinum wire electrode is used as a counter electrode to form a three-electrode system; di(2-ethylhexyl) phthalate in a sample to be measured is quantitatively captured on the surface of the sensor; and detection is realized through a luminescence signal generated.

8. The detection method according to claim 7, characterized in that, The detection method is specifically operated as follows: S1, preparation of a PBS nanobubble buffer solution containing K2S2O8; S2, preparation of standard solutions of di(2-ethylhexyl) phthalate with different concentrations; S3, draw a standard curve, respectively, the electrochemiluminescence aptamer sensor is soaked in the same amount of standard solution prepared in step S2 and reacted for the same time, so that the electrochemiluminescence aptamer sensor binds to the phthalic acid di (2-ethylhexyl) ester, DEHP / COOH-apt / Zr-MOF / GDY / GCE is obtained, then it is used as a working electrode, Ag / AgCl is used as a reference electrode, and platinum electrode is used as a counter electrode to form a three-electrode system, with the PBS nanobubble buffer solution containing K2S2O8 in step S1 as an electrolyte, cyclic voltammetry scanning is carried out, the luminescence intensity-time curve is recorded, the linear relationship between the luminescence intensity before and after the electrochemiluminescence aptamer sensor binds to the phthalic acid di (2-ethylhexyl) ester and the logarithmic value of the phthalic acid di (2-ethylhexyl) ester concentration in the phthalic acid di (2-ethylhexyl) ester standard solution is established, and a corresponding linear regression equation is obtained; S4, detection of phthalic acid di (2-ethylhexyl) ester in the sample to be tested, according to step S3, the sample to be tested and the electrochemiluminescence aptamer sensor surface are reacted for the same time, so that the electrochemiluminescence aptamer sensor binds to the phthalic acid di (2-ethylhexyl) ester, then it is used as a working electrode, and the method of step S3 is used to detect the luminescence intensity, and the concentration of phthalic acid di (2-ethylhexyl) ester in the sample to be tested is calculated according to the linear regression equation.

9. The detection method according to claim 8, characterized in that, The conditions of the cyclic voltammetry scanning are that the electrochemical window range is-2.0~0V, the photomultiplier high voltage is 800V, and the scanning speed is 0.1V / s.

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