Novel column [6] arene derivative-acetylene black composite material modified electrode and preparation method and application thereof

Abstract

The invention discloses a novel column [6] arene derivative-acetylene black composite material modified electrode and a preparation method and application thereof. The preparation method of the modified electrode comprises the following steps: preparing dihydroxy column [6] arene and a tripolyindole derivative, bonding the dihydroxy column [6] arene and the tripolyindole derivative under the action of sodium hydride by a Williamson ether method, synthesizing to obtain a novel column [6] arene derivative, preparing the novel column [6] arene derivative and acetylene black into a dispersion system, dispensing the dispersion system on the surface of a clean glassy carbon electrode, and drying to obtain the modified electrode. The modified electrode P6-TATR / AB / GCE is obtained. The modified electrode P6-TATR / AB / GCE has the advantages of high sensitivity, strong selectivity, low detection limit, wide linear range, good reproducibility, high recovery rate, good stability and the like.

Description

Technical Field

[0001] The present invention relates to the field of electrochemical analysis technology, in particular to a modified electrode of a novel column[6]arene derivative-acetylene black composite material and a preparation method and application thereof. Background Art

[0002] Pillar[6]arene is a cyclic macromolecule composed of six benzene rings connected by methylene bridges. Its unique structure features a hollow, columnar cavity. This molecular structure endows pillar[6]arene with excellent molecular recognition, inclusion, and catalytic properties. Due to its unique columnar structure and modifiability, pillar[6]arene has shown broad application prospects in a variety of fields, including molecular recognition and sensing, drug delivery systems, catalytic reaction promotion, environmental pollutant removal, and the development of new materials.

[0003] Electrochemical detection technology is an analytical method based on electrochemical principles. It enables qualitative or quantitative analysis of target substances by measuring parameters such as current, potential, conductivity, or charge in an electrochemical system. This technology offers high sensitivity, good selectivity, ease of operation, and low cost, and is widely used in environmental monitoring, biomedicine, food safety, industrial process control, and other fields.

[0004] Currently commercialized electrochemically modified electrodes include enzyme-modified electrodes (such as lactate sensors), nanomaterial-modified electrodes (such as carbon nanotubes and gold nanoparticles), polymer film-modified electrodes (such as Nafion membranes), and metal oxide-modified electrodes (such as tin oxide). These materials have disadvantages such as poor stability, poor reproducibility, large mass transfer resistance, and low sensitivity.

[0005] In view of the existing defects, the present invention is based on the excellent electrical conductivity and good electrode compatibility of acetylene black. The acetylene black nanocomposite material based on pillar[6]arene-tripolyindole derivatives is prepared by synthesis and simple doping-drop coating strategy, and is modified on the surface of glassy carbon electrode. Summary of the Invention

[0006] Based on this, the present invention provides a novel modified electrode of a column [6] aromatic hydrocarbon derivative-acetylene black composite material, a preparation method thereof and an application thereof. The present invention utilizes a synthesis and a simple doping-drop coating strategy to prepare an acetylene black nanocomposite material based on a column [6] aromatic hydrocarbon-tripolyindole derivative. The prepared novel composite material modified electrode P6-TATR / AB / GCE has the advantages of high sensitivity, strong selectivity, low detection limit, wide linear range, good reproducibility, high recovery rate and good stability.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A modified electrode of a novel column[6]arene derivative-acetylene black composite material is disclosed. Dihydroxy column[6]arene and tripolyindole derivatives are first prepared. The dihydroxy column[6]arene and tripolyindole derivative are bonded with each other in the presence of sodium hydride by the Williamson ether method to synthesize a novel column[6]arene derivative. The novel column[6]arene derivative and acetylene black are then prepared into a dispersion system, which is drop-coated on the surface of a clean glassy carbon electrode to obtain a modified electrode P6-TATR / AB / GCE.

[0009] The preparation method of the modified electrode of the novel column [6] aromatic hydrocarbon derivative-acetylene black composite material is carried out according to the following steps:

[0010] (1) Synthesis of triindole derivatives:

[0011] S1: Take 8-12 g of 2-indolone, add 25-35 mL of phosphorus oxychloride, and carry out a cyclization reaction at 95-105°C for 7-9 hours. Cool to room temperature, pour into ice water and stir continuously to produce a solid substance. After no solid substance is produced, adjust the pH to neutral with 5M sodium hydroxide solution, filter, wash with water 2-4 times, 25-35 mL each time, and then dry at 45-55°C for 4-6 hours to obtain a dry filter cake. Chromatography on a silica gel column is performed, and the eluent is a mixture of petroleum ether and ethyl acetate in a volume ratio of 4-6:1. The chromatographic solution is collected, concentrated, and evaporated to dryness to obtain a solid substance, which is tripolyindole;

[0012] S2: 1.8-2.2 g of tripolyindole, 550-650 mg of tetrabutylammonium bromide, and 5.8-6.5 g of potassium hydroxide were added to 35-45 mL of tetrahydrofuran solution, refluxed at 70-90 ° C under nitrogen for 25-35 min, 1.75-1.90 mL of 1-bromohexane was added, and refluxed for 11-13 hours. The mixture was cooled to room temperature, 25-35 mL of dichloromethane was added, and the mixture was extracted with water 2-4 times, 80-120 mL each time. The organic layer was collected and dried over 2.5-3.5 g of anhydrous Na2SO4, and concentrated. The concentrate was chromatographed on a silica gel column with 230-260 mL of a mixture of petroleum ether and ethyl acetate as the eluent, wherein the volume ratio of petroleum ether to ethyl acetate was 75-85:1. The mixture was concentrated and evaporated to dryness to give a white solid, namely tri-N-hexyl tripolyindole;

[0013] S3: Take 1.0-1.2g of tri-N-hexyltriindole and dissolve it in 18-22mL of chloroform at room temperature, slowly add 160-175μL of concentrated nitric acid and react for 1.8-2.2h, extract and wash with water 2-4 times, 25-35mL each time, collect the organic phase, dry the organic phase with 1.5-2.5g of anhydrous Na2SO4, and then concentrate to obtain a concentrate. The concentrate is chromatographed on a silica gel column, and the eluent is a mixture of petroleum ether and dichloromethane 280-320mL, the volume ratio of petroleum ether to dichloromethane is 1.8-2.2:1, collect the chromatographic liquid, concentrate and dry in a water bath to obtain an orange-red solid, take 1.4-1.6g of the orange-red solid, 2.2-2.6g of iron powder and 2.8-3.1g of ammonium chloride and add In a single-necked flask, 35-45 mL of aqueous ethanol and 18-22 mL of ethyl acetate were added, the volume ratio of the aqueous ethanol was 2.8-3.2: 1, refluxed under nitrogen for 20-25 h, cooled to room temperature, extracted 2-4 times with dichloromethane and water, each time using 25-35 mL of dichloromethane and 45-55 mL of water, and the organic phase was collected and dried over 1.8-2.5 g of anhydrous sodium sulfate. The organic phase was concentrated and evaporated to dryness, and the concentrate was chromatographed on a silica gel column with an eluent of 280-350 mL of a mixture of petroleum ether and ethyl acetate in a volume ratio of 1.8-2.2: 1. The mixture was concentrated and dried in a water bath to give a milky white solid, i.e., 3-aminotri-N-hexyltriindole.

[0014] S4: 500-550 mg of 3-aminotri-N-hexyltriindole was dissolved in 4-6 mL of anhydrous tetrahydrofuran, followed by the addition of 345-375 μL of anhydrous triethylamine. The mixture was stirred in an ice bath for 5-15 min, and then 150-175 μL of 4-chloromethylbenzoyl chloride was slowly added. After reacting for 10-20 minutes, the reaction was quenched with 15-25 mL of saturated brine, and then extracted with dichloromethane. The mixture was washed three times with 15-25 mL of water each time. The organic phase was collected and dried over 2.5-3.5 g of anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to 0.2-1 mL. The mixture was purified by silica gel column chromatography, with the eluent being 80-120 mL of a mixed liquid of petroleum ether and dichloromethane in a volume ratio of 1:1.3-1.8. The mixture was concentrated and evaporated to dryness to obtain a light yellow solid, which is the triindole derivative.

[0015] The specific synthesis reaction formula is as follows:

[0016]

[0017] (2) Synthesis of dihydroxy pillar[6]arene:

[0018] SS1: 1,4-dimethoxybenzene 6-7g, paraformaldehyde 1.2-1.5g, 1,2-dichloroethane 80-100mL and trifluoroacetic acid 4.5-5.5mL were placed in a single-necked flask, wherein the 1,2-dichloroethane was an anhydrous solvent. After reflux in an oil bath at 80-100°C under nitrogen protection for 1.8-2.2h, the mixture was cooled to room temperature and poured into 180-220mL of methanol. The solid was ultrasonically washed with 25-35mL of methanol and filtered. The filtrate was naturally dried to obtain the crude product of column [6].

[0019] SS2: The crude product from column [6] was dissolved in 45-55 mL of dichloromethane, and 9-11 mL of a methanol solution containing 1.8-2.0 g of cerium ammonium nitrate was slowly added dropwise. After reacting at room temperature for 1.8-2.2 h, 8-10 mL of a methanol solution containing 1.7-1.8 g of cerium ammonium nitrate was slowly added dropwise again. After reacting for 0.8-1.2 h, 90-110 mL of water was added for extraction. The organic phase was collected and dried with 2.5-3.5 g of anhydrous Na2SO4. The organic layer was then chromatographed on a silica gel column. The eluent was a mixed solution of petroleum ether and dichloromethane (280-320 mL). The volume ratio of petroleum ether to dichloromethane was 0.9-1.1:2. The product was concentrated and evaporated to dryness to obtain a red solid P6O2.

[0020] SS3: Take 850-900 mg of red solid P6O2 and dissolve it in 9-11 mL of dichloromethane. Add 9-11 mL of methanol solution containing 45-55 mg of sodium borohydride under nitrogen protection, and react until the solution becomes colorless and transparent. Quench with 4-6 mL of water and extract. Collect the organic phase, then dry the organic layer with 0.8-1.2 g of anhydrous Na2SO4, concentrate and evaporate to dryness to obtain a white solid, that is, dihydroxy column [6] aromatic hydrocarbon;

[0021] The specific synthesis reaction formula is as follows:

[0022]

[0023] (3) Synthesis of novel pillar[6]arene derivatives:

[0024] Take 140-160 mg of dihydroxy column [6] aromatic hydrocarbon and 15-17 mg of sodium hydride and mix them in 2.5-3.5 mL of N, N-dimethylformamide, which is an anhydrous solvent. Stir for 25-35 minutes under nitrogen atmosphere, add 300-350 mg of tripolyindole derivative, stir at 40-50 ° C for 20-25 hours, cool, extract with 8-12 mL of dichloromethane and 18-22 mL of saturated brine, and wash with reverse osmosis water for 3 minutes. -5 times of organic phase to remove residual N, N-dimethylformamide, the amount of reverse osmosis water used each time is 18-22 mL, the organic layer is collected, and the organic layer is dried with 0.8-1.2 g of anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and the concentrate is purified by silica gel column chromatography, the eluent is a mixed solution of petroleum ether and dichloromethane 45-55 mL, the petroleum ether and dichloromethane are in a volume ratio of 1.8-2.2:1, concentrated and evaporated to dryness to obtain a brown solid, that is, a new column [6] aromatic derivative;

[0025] The specific synthesis reaction formula is as follows:

[0026]

[0027] (4) Preparation method of modified electrode:

[0028] SSS1: Polish a glassy carbon electrode with 250-350μm Al2O3 for 1.5-3 minutes, then polish it with 40-60μm Al2O3 for 1.5-3 minutes. Then, ultrasonically clean it with ultrapure water for 2-4 times, each time for 8-15 seconds, and then ultrasonically clean it with anhydrous ethanol for 8-15 seconds. The electrode is then dried at room temperature to obtain a clean glassy carbon electrode for use.

[0029] SSS2: 2.5-3.5 mg of acetylene black was added to 0.8-1.5 mL of DMF and ultrasonically dispersed for 25-35 min. Then, 1.5-2.5 mg of the novel column[6] aromatic derivative was added and ultrasonically dispersed again for 25-35 min to obtain a P6-TATR / AB composite dispersion.

[0030] SSS3: Use a pipette to transfer 8-15 μL of the P6-TATR / AB composite material dispersion and apply it dropwise on the clean surface of the glassy carbon electrode. After drying under an infrared lamp for 25-35 minutes, the electrode surface is rinsed with deionized water and allowed to air dry naturally to obtain the modified electrode P6-TATR / AB / GCE.

[0031] In the aforementioned step (1), the synthesis method of the triindole derivative is:

[0032] S1: Take 10 g of 2-indolone, add 30 mL of phosphorus oxychloride, and carry out cyclization reaction at 98°C for 8 hours. Cool to room temperature, pour into ice water and stir continuously to produce solid matter. After no solid matter is produced, adjust the pH to neutral with 5M sodium hydroxide solution, filter, wash with water 3 times, each time with 30 mL, and then dry at 50°C for 5 hours to obtain a dry filter cake. Chromatography on a silica gel column is performed, and the eluent is a mixture of petroleum ether and ethyl acetate in a volume ratio of 5:1. The chromatographic solution is collected, concentrated and evaporated to dryness to obtain a solid matter, which is tripolyindole;

[0033] S2: 2.0 g of triindole, 596 mg of tetrabutylammonium bromide, and 6.2 g of potassium hydroxide were added to 40 mL of tetrahydrofuran solution, and the mixture was refluxed at 80° C. under nitrogen for 30 min. 1-bromohexane 1.83 mL was added and refluxed for 12 hours. The mixture was cooled to room temperature, 30 mL of dichloromethane was added, and the mixture was extracted with water three times, 100 mL each time. The organic layer was collected and dried over 3 g of anhydrous Na2SO4, and concentrated to 0.2-1.0 mL. The concentrate was chromatographed on a silica gel column with 243 mL of a mixture of petroleum ether and ethyl acetate as the eluent, wherein the volume ratio of petroleum ether to ethyl acetate was 80:1. The mixture was concentrated and evaporated to dryness to give a white solid, namely tri-N-hexyltriindole;

[0034] S3: 1.12 g of tri-N-hexyltriindole was dissolved in 20 mL of chloroform at room temperature, 168 μL of concentrated nitric acid was slowly added dropwise and reacted for 2 h, the mixture was extracted and washed with water 3 times, 30 mL each time, the organic phase was collected, the organic phase was dried with 2 g of anhydrous Na2SO4, and then concentrated to 0.2-1.0 mL to obtain a concentrate, which was chromatographed on a silica gel column with an eluent of 300 mL of a mixture of petroleum ether and dichloromethane in a volume ratio of 2:1. The chromatographic solution was collected and concentrated and dried in a water bath to obtain an orange-red solid. 1.51 g of the orange-red solid, 2.46 g of iron powder and 2.97 g of ammonium chloride were added Pour into a single-necked flask, add 40mL of ethanol aqueous solution and 20mL of ethyl acetate, the volume ratio of the ethanol aqueous solution is 3:1, reflux under nitrogen protection for 22h, cool to room temperature, extract with dichloromethane and water 3 times, each time the amount of dichloromethane is 30mL, the amount of water is 50mL, collect the organic phase, then dry the organic phase with 2g of anhydrous sodium sulfate, concentrate and evaporate to dryness, the concentrate is chromatographed on a silica gel column, the eluent is a mixture of petroleum ether and ethyl acetate 300mL, the volume ratio of petroleum ether and ethyl acetate is 2:1, concentrate and dry in a water bath to give a milky white solid, i.e., 3-aminotri-N-hexyltriindole;

[0035] S4: Take 526 mg of 3-aminotri-N-hexyltriindole, dissolve it in 5 mL of anhydrous tetrahydrofuran, then add 366 μL of anhydrous triethylamine, stir in an ice bath for 10 minutes, and then slowly add 164 μL of 4-chloromethylbenzoyl chloride. After reacting for 15 minutes, quench the reaction with 20 mL of saturated brine, extract with dichloromethane, wash three times with water, add 20 mL of water each time, collect the organic phase, and then dry the organic phase with 3 g of anhydrous sodium sulfate, filter, and concentrate under reduced pressure to 0.2-1 mL. Purify by silica gel column chromatography, the eluent is 100 mL of a mixed liquid of petroleum ether and dichloromethane, and the volume ratio of petroleum ether and dichloromethane is 1:1.5. Concentrate and evaporate to dryness to obtain a light yellow solid, which is the triindole derivative.

[0036] In the aforementioned step (2), the synthesis method of dihydroxy pillar [6] aromatic hydrocarbons is as follows:

[0037] SS1: 6.21 g of 1,4-dimethoxybenzene, 1.35 g of paraformaldehyde, 90 mL of 1,2-dichloroethane and 5 mL of trifluoroacetic acid were placed in a single-necked flask, with the 1,2-dichloroethane being an anhydrous solvent. The mixture was refluxed in an oil bath at 90 °C for 2 h under nitrogen protection, then cooled to room temperature, poured into 200 mL of methanol, and filtered. The solid was ultrasonically washed with 30 mL of methanol and filtered. The filtrate was naturally dried to obtain the crude product of column [6].

[0038] SS2: The crude product from column [6] was dissolved in 50 mL of dichloromethane, and 10 mL of a methanol solution containing 1.90 g of cerium ammonium nitrate was slowly added dropwise. After reacting at room temperature for 2 h, 9 mL of a methanol solution containing 1.76 g of cerium ammonium nitrate was slowly added dropwise again. After reacting for 1 h, 100 mL of water was added for extraction. The organic phase was collected and dried over 3 g of anhydrous Na2SO4. The organic layer was then chromatographed on a silica gel column. The eluent was a mixed solution of 300 mL of petroleum ether and dichloromethane, with a volume ratio of 1:2. The mixture was concentrated and evaporated to dryness to obtain a red solid P6O2.

[0039] SS3: 872 mg of red solid P6O2 was dissolved in 10 mL of dichloromethane. Under nitrogen protection, 10 mL of methanol solution containing 51 mg of sodium borohydride was added. The reaction was continued until the solution became colorless and transparent. The solution was quenched with 5 mL of water and extracted. The organic phase was collected and dried with 1 g of anhydrous Na2SO4. The organic layer was concentrated and evaporated to dryness to obtain a white solid, i.e., dihydroxy columnar [6] aromatic hydrocarbon.

[0040] In the aforementioned step (3), the synthesis method of the novel pillar[6]arene derivative is:

[0041] Take 150 mg of dihydroxy column [6] aromatic hydrocarbon and 16 mg of sodium hydride and mix them in 3 mL of N,N-dimethylformamide, wherein the N,N-dimethylformamide is an anhydrous solvent, stir for 30 minutes under a nitrogen atmosphere, add 330 mg of tripolyindole derivative, stir at 45 ° C for 22 hours, cool, extract with 10 mL of dichloromethane and 20 mL of saturated brine, wash the organic phase with reverse osmosis water 4 times to remove residual N,N-dimethylformamide, the amount of reverse osmosis water used each time is 20 mL, collect the organic layer, dry the organic layer with 1 g of anhydrous sodium sulfate, filter, concentrate under reduced pressure, and purify the concentrate by silica gel column chromatography, the eluent is 50 mL of a mixed solution of petroleum ether and dichloromethane, wherein the petroleum ether and dichloromethane are in a volume ratio of 2:1, concentrate and evaporate to dryness to obtain a brown solid, that is, a new column [6] aromatic hydrocarbon derivative.

[0042] In the aforementioned step (4), the synthesis method of the novel pillar[6]arene derivative is:

[0043] SSS1: Polish a glassy carbon electrode with 280-320 μm Al2O3 for 1.5-2.5 min, then polish it with 45-55 μm Al2O3 for 1.5-2.5 min, then ultrasonically clean it with ultrapure water for 2-4 times, each time for 8-12 seconds, and then ultrasonically clean it with anhydrous ethanol for 8-12 seconds. The electrode is then dried at room temperature to obtain a clean glassy carbon electrode for later use.

[0044] SSS2: 2.8-3.2 mg of acetylene black was added to 0.8-1.2 mL of DMF and ultrasonically dispersed for 28-32 min. Then, 1.8-2.2 mg of the novel column[6] aromatic derivative was added and ultrasonically dispersed again for 28-32 min to obtain a P6-TATR / AB composite dispersion.

[0045] SSS3: Use a pipette to transfer 8-12 μL of the P6-TATR / AB composite material dispersion and apply it on the clean surface of the glassy carbon electrode. After drying under an infrared lamp for 28-32 minutes, the electrode surface is washed with deionized water and allowed to air dry naturally to obtain the modified electrode P6-TATR / AB / GCE.

[0046] Specifically, in the aforementioned step (4), the preparation method of the modified electrode is:

[0047] SSS1: Polish a glassy carbon electrode with 300 μm Al2O3 for 2 min, then with 50 μm Al2O3 for 2 min, then ultrasonically clean it with ultrapure water for 10 s three times, then ultrasonically clean it with anhydrous ethanol for 10 s. Dry the electrode at room temperature to obtain a clean glassy carbon electrode for later use.

[0048] SSS2: 3 mg of acetylene black was added to 1 mL of DMF and dispersed with ultrasound for 30 min. Then 2 mg of the novel column[6]arene derivative was added and dispersed with ultrasound again for 30 min to obtain a P6-TATR / AB composite dispersion.

[0049] SSS3: Use a pipette to transfer 10 μL of the P6-TATR / AB composite material dispersion and apply it dropwise on the clean surface of the glassy carbon electrode. After drying under an infrared lamp for 30 minutes, the electrode surface is washed with deionized water and allowed to air dry naturally to obtain the modified electrode P6-TATR / AB / GCE.

[0050] Application of the aforementioned modified electrode in electrochemical detection.

[0051] The modified electrode can realize sensitive and selective analysis of positively charged analytes in aqueous solution, and the modified electrode can detect diquat.

[0052] Beneficial effects:

[0053] 1. The present invention synthesizes the target supramolecular pillar[6]arene-tripolyindole derivatives by the Williamson ether method, and prepares acetylene black nanocomposites based on pillar[6]arene-tripolyindole derivatives by using the synthesis and simple doping-drop coating strategy, and modifies them on the surface of a glassy carbon electrode. The electrode has the advantages of high sensitivity, strong selectivity, low detection limit, wide linear range, good reproducibility, high recovery rate, and good stability.

[0054] 2. The novel composite material prepared by doping AB with the novel compound P6-TATR designed and synthesized in this invention combines the advantages of the suitable cavity inclusion capacity of the pillar[6]arene structure, the electron-rich properties of the tripolyindole derivative structure, and the excellent conductivity of acetylene black. The prepared modified electrode can achieve sensitive and selective analysis of positively charged analytes in aqueous solution. At the same time, after being modified on a glassy carbon electrode, the material has a uniform nanoparticle morphology, effectively increasing its contact area with the analyte, further improving the analytical sensitivity of the target analyte.

[0055] 3. The pillar[6]arene-trimer derivative and acetylene black synthesized in the present invention are both hydrophobic substances, and both the acetylene black and the trimer derivative structure introduced into the pillar[6]arene have excellent electrode compatibility. The composite material exhibits excellent stability and tolerance when detecting analytes in an aqueous phase. The pillar[6]arene-trimer derivative is doped with the highly conductive and electrode-compatible hydrophobic acetylene black to form a composite material. When prepared into an electrode, the material has high sensitivity for detecting diquat. The P6-TATR / AB / GCE electrode has good accuracy, durability, and anti-interference ability, ensuring the reliability and specificity of diquat detection in actual samples.

[0056] Description of the drawings:

[0057] Figure 1 is the H NMR spectrum of TAT;

[0058] Figure 2 is the H NMR spectrum of TATR;

[0059] Figure 3 This is the H NMR spectrum of TATR-NO2;

[0060] Figure 4 is the H NMR spectrum of TATR-NH2;

[0061] Figure 5 is the H NMR spectrum of TATR-NHPhCH2Cl;

[0062] Figure 6 is the H NMR spectrum of pillar[6]arene (P6);

[0063] Figure 7 is the H NMR spectrum of P6O2;

[0064] Figure 8 This is the H NMR spectrum of dihydroxy pillar[6]arene (P6(OH)2);

[0065] Figure 9 is the H NMR spectrum of P6-TATR;

[0066] Figure 10 is the C NMR spectrum of P6-TATR;

[0067] Figure 11 is the mass spectrum of P6-TATR;

[0068] Figure 12 Scanning electron micrographs of AB modified electrode and P6-TATR / AB composite material modified electrode (a is AB modified electrode at 5.00KX magnification; b is AB modified electrode at 10.00KX magnification; c is P6-TATR / AB composite material modified electrode at 5.00KX magnification; d is P6-TATR / AB composite material modified electrode at 10.00KX magnification);

[0069] Figure 13 IR spectra of AB, P6-TATR and P6-TATR / AB composite material;

[0070] Figure 14 CV curves of GCE, AB / GCE, P6-TATR / GCE and P6-TATR / AB / GCE electrodes in 5 mM K4 / K3[Fe(CN)6] solution containing 0.1 M KCl;

[0071] Figure 15 Nerquist plots of GCE, AB / GCE, P6-TATR / GCE, and P6-TATR / AB / GCE electrodes in 5 mM K4 / K3[Fe(CN)6] solution containing 0.1 M KCl;

[0072] Figure 16 CV curve of P6-TATR / AB / GCE electrode in 5 mM K4 / K3[Fe(CN)6] solution with 20 scans;

[0073] Figure 17 CV curves of each electrode in BR buffer with pH 8.00 containing 10 μM DQ;

[0074] Figure 18 SWV curves of the P6-TATR / AB / GC electrode in BR buffer (pH 8.00) containing 0.001-16.00 μM DQ;

[0075] Figure 19 is the linear fitting curve of the peak current value and concentration corresponding to the SWV curve;

[0076] Figure 20 is the relative error of the peak current value of the interferents (a is the relative error of the peak current value of 8 pesticide interferents containing 100 μM in 1.00 μM DQ BR buffer at pH 8.00; b is the relative error of the peak current value of 9 cationic and 4 anionic interferents containing 100 μM in 1.00 μM DQ BR buffer at pH 8.00). DETAILED DESCRIPTION

[0077] The present invention will be further described below with reference to the examples, but they are not intended to limit the present invention.

[0078] Unless otherwise specified, the chemical reagents used in the embodiments of the present invention are all commercially available products commonly used in the art. Equivalent substitutes for the reagents used in the present invention are deemed to fall within the scope of protection of the present invention as long as they meet the technical specifications.

[0079] The synthesis of pillar[6]arene-trimerized indole derivatives (P6-TATR) is mainly achieved by the Williamson ether method. Dihydroxy pillar[6]arene (P6(OH)2) and trimerized indole derivatives (TATR-NHPhCH2Cl) are bonded under the action of sodium hydride.

[0080] 1. Main test reagents

[0081] The reagents used in the experiments were of analytical grade and were not further purified. Diquat dibromide (China Institute of Metrology), acetylene black, phoxim, and naptalam were purchased from Aladdin. Pymetrozine, quinalphos, and nitenpyram were purchased from Tanmo Quality Inspection Technology Co., Ltd., China. Penconazole was purchased from TargetMol Chemical Company, USA. Thiabendazole and glufosinate-ammonium were purchased from Shanghai MacLean Biochemical Technology Co., Ltd. Limited Company 2-oxindole, 1-bromhexine, 4-(Chloromethyl)benzoyl chloride, 1,4-dimethoxybenzene, tetrabutylammonium bromide, trifluoroacetic acid, ammonium ceric nitrate, sodium hydride, phosphorusoxychloride, and iron powder were purchased from Beijing Inokai Technology Co., Ltd.

[0082] Example 1:

[0083] Synthesis and Structural Characterization of Triindole Derivatives (TATR-NHPhCH2Cl)

[0084] TATR-NHPhCH2Cl was synthesized according to scheme 1. 2-Indole was used as a raw material to undergo a cyclization reaction in phosphorus oxychloride to obtain triindole (TAT), and then TAT was alkylated to prepare tri-N-hexyl triindole (TATR). Subsequently, TATR was nitrated at room temperature to obtain 3-nitro-tri-N-hexyl triindole, which was reduced with iron powder to obtain 3-aminotri-N-hexyl triindole TATR-NH2. Finally, TATR-NH2 was acylated with 4-chloromethylbenzoyl chloride to obtain the intermediate TATR-NHPhCH2Cl. The specific steps are as follows:

[0085] (1) 10 g (75 mmol) of 2-indolone was added to 30 mL of phosphorus oxychloride, and a cyclization reaction was carried out at 98° C. for 8 hours. The mixture was cooled to room temperature, poured into ice water and stirred continuously to produce a solid substance. After no solid substance was produced, the pH was adjusted to neutral with 5 M sodium hydroxide solution, filtered, washed with water 3 times, 30 mL each time, and then dried at 50° C. for 5 hours to obtain a dry filter cake. The filter cake was chromatographed on a silica gel column, and the eluent was a mixture of petroleum ether and ethyl acetate 2.4 L, wherein the volume ratio of petroleum ether to ethyl acetate was 5:1. The chromatographic solution was collected, concentrated, and evaporated to dryness to obtain 2.2 g of a solid substance, namely tripolyindole (TAT), with a yield of 25.4%;

[0086] (2) 2.0 g (5.8 mmol) of triindole, 596 mg (1.85 mmol) of tetrabutylammonium bromide, and 6.2 g (110 mmol) of potassium hydroxide were added to 40 mL of tetrahydrofuran solution. The mixture was refluxed at 80°C for 30 min under nitrogen protection. 1.83 mL of 1-bromohexane was added and refluxed for 12 hours. The mixture was cooled to room temperature, 30 mL of dichloromethane was added, and the mixture was extracted with water three times, each time with 100 mL. The organic layer was collected and dried over 3 g of anhydrous Na2SO4. The organic layer was concentrated and the concentrate was chromatographed on a silica gel column. The eluent was a mixture of petroleum ether and ethyl acetate (243 mL, with a volume ratio of petroleum ether to ethyl acetate of 80:1). The mixture was concentrated and evaporated to dryness to obtain 3.01 g of a white solid, namely tri-N-hexyltriindole (TATR), with a yield of 87%.

[0087] (3) 1.12 g (1.18 mmol) of tri-N-hexyltriindole was dissolved in 20 mL of chloroform at room temperature, and 168 μL (3.76 mmol) of concentrated nitric acid was slowly added dropwise and reacted for 2 h. The mixture was extracted and washed with water 3 times, 30 mL each time. The organic phase was collected and dried with 2 g of anhydrous Na2SO4. The organic phase was concentrated to 0.2-1.0 mL to obtain a concentrated solution. The concentrated solution was chromatographed on a silica gel column with 300 mL of a mixture of petroleum ether and dichloromethane as the eluent. The volume ratio of petroleum ether to dichloromethane was 2:1. The chromatographic solution was collected and concentrated and dried in a water bath to obtain 1.08 g of an orange-red solid with a yield of 90%. 1.51 g (2.35 mmol) of an orange-red solid and 2.46 g (44 mmol) of iron powder were taken. l) and ammonium chloride 2.97g (56mmol) were added to a single-necked flask, 40mL of aqueous ethanol and 20mL of ethyl acetate were added, the volume ratio of the aqueous ethanol was 3:1, and the mixture was refluxed under nitrogen for 22h, cooled to room temperature, and extracted 3 times with dichloromethane and water, each time with 30mL of dichloromethane and 50mL of water. The organic phase was collected and dried over 2g of anhydrous sodium sulfate, concentrated and evaporated to dryness, and the concentrate was chromatographed on a silica gel column with 300mL of a mixture of petroleum ether and ethyl acetate as the eluent, the volume ratio of petroleum ether and ethyl acetate being 2:1. The mixture was concentrated and evaporated to dryness to give 1.06g of an off-white solid, namely 3-aminotri-N-hexyltriindole (TATR-NH2), in a yield of 73.6%;

[0088] (4) 526 mg of 3-aminotri-N-hexyltriindole was dissolved in 5 mL of anhydrous tetrahydrofuran, and then 366 μL (2.64 mmol) of anhydrous triethylamine was added. After stirring in an ice bath for 10 min, 164 μL (1.3 mmol) of 4-chloromethylbenzoyl chloride was slowly added. After reacting for 15 minutes, the reaction was quenched with 20 mL of saturated brine, and then extracted with dichloromethane. The mixture was washed three times with 20 mL of water each time. The organic phase was collected and dried over 3 g of anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to 0.2-1 mL. The mixture was purified by silica gel column chromatography. The eluent was 100 mL of a mixed liquid of petroleum ether and dichloromethane, wherein the volume ratio of petroleum ether to dichloromethane was 1:1.5. The mixture was concentrated and evaporated to dryness to obtain 592 mg of a light yellow solid, i.e., the triindole derivative (TATR-NHPhCH2Cl) with a yield of 92.9%;

[0089] Structural characterization: The H NMR spectra of TAT, TATR, TATR-NO2, TATR-NH2 and TATR-NHPhCH2Cl are shown in Figure 1-Figure 5 . 1H NMR (400MHz, CDCl3) δ8.27(d,J=4.4Hz,2H),8.17(s,1H),8.05(s,1H)7.95(d,J=5.3Hz,2H),7.59(d,J=5.4Hz,2H),7.53(t,J=4 .6Hz,2H),7.44(s,2H),7.37-7.27(m,2H),4.89(s,6H),4.64(s,2H),2.0-1.93(m,6H),1.26-1.22(m,18H),0.81-0.77(m,9H).

[0090] Example 2

[0091] Synthesis and Structural Characterization of Dihydroxy Pillar[6] Arene (P6(OH)2)

[0092] P6(OH)2 was synthesized according to Scheme 2. First, 1,4-dimethoxybenzene and polyoxymethylene were cyclized under trifluoroacetic acid catalysis to form pillar[6]arene (P6). Subsequently, P6 was oxidized by ammonium cerium nitrate to generate P6O2, which was then reduced to dihydroxy pillar[6]arene (P6(OH)2) using sodium borohydride. The H NMR spectra of P6, P6O2, and P6(OH)2 were (see Figure 6-8 The specific steps are as follows:

[0093] (1) 6.21 g (45 mmol) of 1,4-dimethoxybenzene, 1.35 g (45 mmol) of paraformaldehyde, 90 mL of 1,2-dichloroethane (anhydrous) and 5 mL of trifluoroacetic acid were placed in a single-necked flask, refluxed in an oil bath at 90 °C for 2 h under nitrogen protection, cooled to room temperature, poured into 200 mL of methanol, and filtered. The solid was ultrasonically washed with 30 mL of methanol and filtered. The filtrate was naturally dried to obtain the crude product of column [6].

[0094] (2) The crude product from column [6] was dissolved in 50 mL of dichloromethane, and 10 mL of a methanol solution containing 1.90 g (3.46 mmol) of cerium ammonium nitrate was slowly added dropwise. After reacting at room temperature for 2 h, 9 mL of a methanol solution containing 1.76 g (3.21 mmol) of cerium ammonium nitrate was slowly added dropwise again. After reacting for 1 h, 100 mL of water was added for extraction. The organic phase was collected and dried over 3 g of anhydrous Na2SO4. The organic layer was then chromatographed on a silica gel column. The eluent was 300 mL of a mixed solution of petroleum ether and dichloromethane, with a volume ratio of petroleum ether to dichloromethane of 1:2. The product was concentrated and evaporated to dryness to obtain 3.51 g of red solid P6O2 with a yield of 53.7%.

[0095] (3) 872 mg of red solid P6O2 (1.21 mmol) was dissolved in 10 mL of dichloromethane. 10 mL of methanol solution containing 51 mg of sodium borohydride was added under nitrogen protection. The reaction was continued until the solution became colorless and transparent. The solution was quenched with 5 mL of water and extracted. The organic phase was collected and dried over 1 g of anhydrous Na2SO4. The organic layer was concentrated and evaporated to dryness to obtain a white solid, i.e., dihydroxy pillar [6] aromatic hydrocarbon.

[0096] Example 3

[0097] Synthesis and Structural Characterization of Pillar[6]arene-Triindole Derivative (P6-TATR)

[0098] P6-TATR was synthesized according to Scheme 3. The specific synthesis steps are as follows:

[0099] 150 mg (0.172 mmol) of the dihydroxy pillar [6] aromatic hydrocarbon prepared in Example 2 and 16 mg (0.67 mmol) of sodium hydride were mixed in 3 mL of N,N-dimethylformamide (anhydrous), stirred under a nitrogen atmosphere for 30 minutes, and 330 mg of the tripolyindole derivative prepared in Example 1 was added, stirred at 45°C for 22 hours, and after cooling, extracted with 10 mL of dichloromethane and 20 mL of saturated brine. The organic phase was washed 4 times with reverse osmosis water to remove residual N,N-dimethylformamide, with the amount of reverse osmosis water used each time being 20 mL. The organic layer was collected, dried with 1 g of anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by silica gel column chromatography, and the eluent was a mixed solution of petroleum ether and dichloromethane 50 mL, wherein the petroleum ether and dichloromethane were in a volume ratio of 2:1. The solution was concentrated and evaporated to dryness to obtain 72 mg of a brown solid, i.e., a novel pillar [6] aromatic hydrocarbon derivative P6-TATR, with a yield of 18%.

[0100] Structural characterization

[0101] 1 H NMR (400MHz, CDCl3) δ8.30-8.05 (m, 10H), 7.92 (d, J = 8.1Hz, 4H), δ7.58-7.45 (m,8H),7.40-7.33(m,4H),7.30-7.22(m,6H),6.82(d,J=3.8Hz,2H),6.66(d, J=16.5Hz,10H),4.99-4.73(m,16H),3.77-3.66(m,12H),3.59-3.45(m,24H), 3.34(s,6H),1.89(d,J=6.5Hz,12H),1.22-1.08(m,36H),0.74-0.66(m,18H). 13C NMR (400MHz, CDCl3) δ187.86,150.18,150.01,149.94,149.90,149.81,149.78,149. 17,145.57,132.50,131.47,130.09,128.43,127.99,127.59,127.54,127.41,127.10 ,126.97,126.43,122.52,114.49,113.50,113.28,113.18,112.85,112.78,55.18,55 .05,54.99,54.83,54.55,30.63,28.90,25.51,21.66,13.10.ESI-MS:m / zcalculated for C 152 H 168 N8O 14 NH4 + 2348.3052[M+NH4] + ;found:2348.3730.

[0102] 1 H NMR spectrum (see Figure 9 ), the peaks at chemical shifts of 8.33-8.03, 7.92, 7.58-7.45, 7.40-7.33 and 7.30-7.22 ppm are the protons on the triindole and phenyl structures; the characteristic proton peaks of the n-hexyl chain are at 4.99-4.73, 1.89, 1.22-1.08 and 0.74-0.66 ppm, respectively; the peaks at 6.82 and 6.66 ppm are attributed to the protons on the aromatic rings of the columnar [6] aromatic hydrocarbons in P6-TATR, and the peaks at 3.77-3.66, 3.59-3.45 and 3.34 ppm are the corresponding methyl and methylene protons. 13 C NMR spectrum (see Figure 10 ), the peak of the carbon on the aromatic ring in P6-TATR is between 150.18 and 112.78 ppm; 187.86 ppm (C a ) are attributed to the carbonyl carbon of the P6-TATR structure, 25.51, 21.66 and 13.10 ppm (C b ) is attributed to the carbon of the n-hexyl chain in the TATR structure. 55.18 ppm (C c ) near the peaks belonging to the methyl carbon in the column [6] aromatic column structure, 30.63 and 28.90 ppm (C d ) belongs to the methylene carbon of column [6] aromatic hydrocarbon column. The presence of these characteristic carbon peaks further indicates the correct structure of the target compound. The expected mass of P6-TATR compound ([M+NH4] +) was 2348.3052Da, and the measured [M+NH4] + 2348.3730Da (see Figure 11 ), further demonstrating the successful synthesis of the target compound.

[0103] Example 4

[0104] Preparation of modified electrodes based on P6-TATR and acetylene black composite materials

[0105] (1) Polishing and cleaning of glassy carbon electrodes

[0106] The glass carbon electrode (GCE) was polished with 300 μm and 50 μm Al2O3 for 2 min respectively, and then ultrasonically cleaned with ultrapure water for 3 times, each time for 10 s, and then ultrasonically cleaned with anhydrous ethanol for 10 s. The electrode was then dried at room temperature for use.

[0107] (2) Preparation of P6-TATR and acetylene black composite dispersion

[0108] 3 mg of acetylene black (AB) was added to 1 ml of DMF and dispersed with ultrasound for 30 minutes. Then, 2 mg of P6-TATR (Example 3) was added and dispersed with ultrasound again for 30 minutes to obtain a P6-TATR / AB composite material dispersion.

[0109] (3) Preparation of modified electrodes

[0110] Use a pipette to transfer 10 μL of the P6-TATR / AB composite material dispersion in step (2) and apply it to the clean glassy carbon electrode surface. After drying under an infrared lamp for 30 minutes, the electrode surface is washed with deionized water and allowed to air dry naturally to obtain a modified electrode P6-TATR / AB / GCE.

[0111] Comparative Example 1

[0112] (1) Polishing and cleaning of glassy carbon electrodes

[0113] The glass carbon electrode (GCE) was polished with 300 μm and 50 μm Al2O3 for 2 min respectively, and then ultrasonically cleaned with ultrapure water for 3 times, each time for 10 s, and then ultrasonically cleaned with anhydrous ethanol for 10 s. The electrode was then dried at room temperature.

[0114] (2) Preparation of P6-TATR and acetylene black composite dispersion

[0115] 3 mg of acetylene black (AB) was added to 1 ml of DMF and dispersed with ultrasound for 30 minutes to obtain an AB / DMF dispersion.

[0116] (3) Preparation of modified electrodes

[0117] Use a pipette to transfer 10 μL of AB / DMF dispersion onto the clean surface of the glassy carbon electrode. After drying under an infrared lamp for 30 minutes, the electrode surface is washed with deionized water and allowed to air dry naturally to obtain a modified electrode AB / GCE.

[0118] Comparative Example 2

[0119] (1) Polishing and cleaning of glassy carbon electrodes

[0120] The glass carbon electrode (GCE) was polished with 300 μm and 50 μm Al2O3 for 2 min respectively, and then ultrasonically cleaned with ultrapure water for 3 times, each time for 10 s, and then ultrasonically cleaned with anhydrous ethanol for 10 s. The electrode was then dried at room temperature for use.

[0121] (2) Preparation of P6-TATR and acetylene black composite dispersion

[0122] 2 mg of P6-TATR (Example 3) was added to 1 ml of DMF and dispersed with ultrasound assistance for 30 minutes to obtain a P6-TATR / DMF dispersion.

[0123] (3) Preparation of modified electrodes

[0124] Use a pipette to transfer 10 μL of the above P6-TATR / DMF dispersion system and apply it to the clean surface of the glassy carbon electrode. After drying under an infrared lamp for 30 minutes, the electrode surface is washed with deionized water and allowed to air dry naturally to obtain the modified electrode P6-TATR / GCE.

[0125] The following is an experimental study on electrode characterization and detection performance of the modified electrodes prepared in Example 4, Comparative Example 1 and Comparative Example 2. The specific experimental results are as follows:

[0126] Characterization of 1P6-TATR / AB / GCE electrode and P6-TATR / GCE electrode

[0127] 1.1 Physical properties characterization

[0128] The surface morphology of P6-TATR / AB / GCE electrode and AB / GCE electrode was characterized by scanning electron microscopy, and the structures of P6-TATR, AB, and P6-TATR / AB composite materials were characterized by infrared technology.

[0129] From electron microscope Figure 12 It can be seen that both AB / GCE and P6-TATR / AB / GCE exhibit obvious spherical particle structure. Figure 12a and 12b show the loose, porous and irregular morphology of the AB / GCE sensor. Figure 12 c and 12d show that the P6-TATR / AB / GCE modified electrode has a relatively dense, porous, uniform and regular structure. P6-TATR can evenly adhere to the AB surface, thus causing changes in the AB surface morphology. In addition, compared Figure 12 As can be clearly seen in Figures 12b and 12d, the incorporation of AB into P6-TATR produces a more uniformly distributed surface of beaded spherical nanoparticles. This enhanced uniformity demonstrates the successful assembly of the P6-TATR / AB composite. The uniformly distributed porous spherical nanoparticle structure on the surface of this modified composite increases its contact area with the analyte, thereby enhancing adsorption.

[0130] Infrared spectrum (see Figure 13 ), due to the inherent poor light transmittance of AB, its light transmittance is almost zero. The characteristic peak of P6-TATR / AB is basically the same as that of P6-TATR. 3430cm -1 The broad absorption band at 1665 cm is attributed to the stretching vibration of the NH group. The stretching vibration of the NHC=O group in the amide corresponds to -1 ;3052cm -1 The peaks at 1581, 1506, and 1466 cm-1 are the bending vibrations of the carbon-hydrogen bonds in the aromatic rings. -1 The peaks at 2960-2985cm are attributed to the characteristic peaks of aromatic skeleton; -1 The stretching vibration of CH in the alkyl chain is at 1405 and 1330 cm -1 It is the bending vibration; In addition, at 1212 and 1046 cm -1 The peak at [6] is the stretching vibration of the C-O-C bond in the pillar[6]arene

[46] . The infrared spectroscopy analysis results further confirmed the successful preparation of the P6-TATR / AB composite material.

[0131] 1.2 Electrochemical performance

[0132] The electrochemical properties of the electrode were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in 5 mM K4 / K3[Fe(CN)6] solution containing 0.1 M KCl.

[0133] like Figure 14 As shown, the AB / GCE electrode produced the highest redox current (I pa =198.50μA, I pc=198.07μA). In contrast, the P6-TATR / GCE electrode showed the weakest signal response. The redox peak current of the AB-doped P6-TATR electrode (P6-TATR / AB / GCE) increased significantly, I pa Reaching 86.42μA, I pc reached 86.42μA, which is higher than the corresponding bare GCE (I pa =71.16μA, I pc =71.88μA). This indicates that the P6-TATR / AB composite material has been successfully prepared and successfully modified onto the electrode, and the P6-TATR / GCE electrode has good electrochemical performance. Figure 15 The semicircular portion of the Nyquist plot at higher frequencies reflects the electron transfer resistance (R ct ), R ct The open circuit potentials of bare GCE, P6-TATR / GCE, AB / GCE, and P6-TATR / AB / GCE electrodes in electrolyte are 0.184 V, 0.171 V, 0.184 V, and 0.186 V, respectively. The R values ​​of the four electrodes are determined by fitting the equivalent circuit model shown in the figure. ct value( Figure 15 The resistances of the P6-TATR / AB / GCE electrode are between those of the bare GCE electrode and the AB / GCE electrode, further confirming its good electrochemical performance. Figure 16 The figure shows the P6-TATR / AB / GCE electrode in the potential range of -1000 to 1000 mV, with a value of 100 mVs -1 After 20 CV scans at a scan rate of 100 nm, no obvious changes were observed in the curve, which proved that the P6-TATR / AB / GCE electrode had excellent electrochemical stability.

[0134] 2. Detection performance of P6-TATR / AB / GCE electrode

[0135] Diquat (DQ), a non-selective contact bipyridyl quaternary ammonium herbicide, has become one of the most widely used water-soluble herbicides since the ban on paraquat. Even at low concentrations, it poses significant toxicity risks to humans and animals, potentially leading to multiple organ dysfunction. This study used diquat as a representative target analyte and employed cyclic voltammetry to detect diquat in aqueous solution using newly prepared bare GCE and modified electrodes (AB / GCE, P6-TATRGCE, P6 / AB / GCE, TATRNHPhCH2Cl / AB / GCE, and P6-TATR / AB / GCE).

[0136] The optimization of test experimental conditions includes three parts: electrochemical parameters, electrolyte environment detection, and the amount of electrode modification materials.

[0137] (1) The optimized electrochemical parameters are:

[0138] ① Cyclic voltammetry (CV): electrochemical window -1.0-1.0V, scan rate 0.1Vs -1 , sensitivity 10 -4 AV -1 .

[0139] ② Square wave voltammetry (SWV): electrochemical window -0.9--0.2V, amplitude 50mV, period 0.1s, sensitivity 10 -4 A / V.

[0140] (2) Optimized electrolyte: Britton-Robinson (BR) buffer with a pH of 8.00.

[0141] (3) Optimized material modification amount: uniform dispersion system of 2 mg P6-TATR, 3 mg AB, and 1 mL DMF.

[0142] 2.1 Comparison of detection performance of various modified electrodes for diquat

[0143] like Figure 17 and Figure 18 As shown in the figure, the response of P6-TATR / GCE to DQ is weak. The incorporation of AB enhances the conductivity of the P6-TATR electrode, and the peak current of the P6-TATR / AB / GCE electrode is significantly enhanced. The two intermediates constituting P6-TATR, P6 and TATRNHPhCH2Cl, are doped with AB to prepare P6 / AB / GCE and TATRNHPhCH2Cl / AB / GCE electrodes. Compared with the P6-TATR / AB / GCE electrode, the peak current values ​​of these electrodes when detecting DQ are much smaller than those of the P6-TATR / AB / GCE electrode. The P6-TATR / AB / GCE electrode produces a significant reduction peak when detecting DQ. The peak currents of each electrode in DQ are shown in Table 1.

[0144] Table 1 Peak current values ​​of different electrodes in BR buffer with pH 8.00 containing 10 μM DQ

[0145]

[0146] 2.2 Application of P6-TATR / AB / GCE Electrode

[0147] Diquat is widely used for the rapid control of weeds in farmland, orchards, and non-arable land. However, its residues on vegetables may pose a threat to human health and the ecological environment. Square wave voltammetry (SWV) is a highly sensitive electrochemical analysis technique that combines the characteristics of pulse voltammetry and step-sweep voltammetry. It achieves efficient detection of target substances by applying a square wave potential excitation signal and measuring the response current. Therefore, we used the newly prepared P6-TATR / AB / GCE electrode and the SWV method to analyze and determine DQ in complex matrices of environmental water samples, white radish, and spinach under optimized conditions.

[0148] 2.2.1 Linear range and detection limit of the method

[0149] Under optimized conditions, DQ was detected using the SWV method with a P6-TATR / AB / GCE electrode in a concentration gradient range of 0.001μM to 16μM.

[0150] like Figure 19 As shown, a reduction peak appears at -0.64 V. In the concentration range of 0.001-16.00 mM, the peak current is divided into two linear ranges, 0.001-1.00 μM and 1.00-16.00 μM, respectively. The two calibration curves fitted are I pc 1(μA)=2.1037c+0.6480(R 2 =0.9832) and I pc 2(μA)=0.1110c+2.6433(R 2 =0.9922). Combining the slope of the first linear equation and the standard deviation S of the blank sample, the minimum detection limit of DQ by the P6-TATR / AB / GCE electrode is 7.28×10 -10 mol L -1 , confirming that the sensor has good sensitivity and can quantitatively detect DQ. 2.2.2 Reproducibility and durability of P6-TATR / AB / GCE electrode

[0151] Under optimized conditions, the reproducibility and stability of the P6-TATR / AB / GCE electrode were evaluated. As shown in Table 2, the intra-day and inter-day precision and inter-batch repeatability (RSD%) of the modified electrode were all less than 5.00%. Furthermore, the relative sensitivity of the P6-TATR / AB / GCE electrode within 100 days was calculated from the average of three repeated measurements. The response signal on day 100 was 97.13% of the initial response. After multiple measurements, no significant swelling or shedding of the modified material was observed, which is attributed to the excellent stability of the modified electrode composite material. Compared with existing related reports (Table 2), the modified electrode proposed in the present invention exhibited commendable durability. These results confirm that the P6-TATR / AB / GCE electrode has good repeatability and durability in detecting DQ.

[0152] Table 2 Repeatability, reproducibility (RSD%) and relative sensitivity after long-term storage of P6-TATR / AB / GCE electrodes

[0153]

[0154] Comparison of 2.3P6-TATR / AB / GCE Electrode with Reported DQ Detection Modified Electrodes

[0155] A comprehensive comparison of the P6-TATR / AB / GCE electrode with previously reported modified electrodes (Table 3) shows that the proposed modified electrode achieves detection limits comparable to or superior to most, and exhibits high electrocatalytic activity. Furthermore, the proposed modified electrode exhibits a wider linear range and superior long-term durability.

[0156] Table 3 Comparison of P6-TATR / AB / GCE electrode performance with existing studies

[0157] sensor method Linear range (μM) Minimum detection limit (nM) Stability (% response) <![CDATA[NF a GCE]]> DPV 0.003-0.4 0.21 - <![CDATA[FAP b -CPE]]> SWV 0.5-100 31 - Kaolin-CPE SWV 0-80 4.21 - Dental amalgam electrode SWV 0.498-1.96 29.0 - Boron-doped diamond electrode SWV 0.099-0.99 0.16 - <![CDATA[NP c / Pt]]> DPV 1.0-160 5.32 - Bismuth film / copper electrode SWV 0.19-9.3 89 - <![CDATA[CA DNA–GNP d electrode]]> DPV 0.001-1.26 0.20 98%, 3 months <![CDATA[ND-MS e / GCE]]> SWV 0.5-46 110 - <![CDATA[β-CD f / hydroxyapatite / GCE]]> DPV 0.05-0.45 0.466 96%,7 days <![CDATA[Pal / Super-P g / GCE]]> DPV 0.00050-1.00 0.1514 86.7%,30 days <![CDATA[MWCNT / NiTsPc LbL h films]]> DPV 1.3-6.7 962 - <![CDATA[CFP-1000 i electrode]]> DPV 0.025-0.75 1.00 - <![CDATA[P6-TATR / AB j / GCE]]> SWV 0.001-1.00,1.00-16 0.782 97.1%,100days

[0158] a NF: Nafion

[0159] b FAP: Fluorapatite

[0160] c NP: natural phosphate

[0161] d CA DNA-GNP: adenine-DNA / gold nanoparticles

[0162] e ND-MS: Nanodiamond-tapioca starch

[0163] f β-CD: β-cyclodextrin

[0164] g Pal / Super-P: Magnesium aluminum quartz / Carbon black

[0165] h MWCNT / NiTsPc LbL: layer-by-layer assembly of MWCNT / NiTsPc

[0166] i CFP: Ceramic Fiber Paper

[0167] j AB: Acetylene black

[0168] 2.4 Investigation of the Anti-interference Performance of P6-TATR / AB / GCE Electrode in Various Pesticides and Ions

[0169] The specific detection of DQ by the electrode in the presence of interferences was further evaluated. The test involved eight herbicides, fungicides, and insecticides (naphthalenesulfonate, glufosinate, thiabendazole, penconazole, nitenpyram, quinalphos, pymetrozine, and phoxim); in addition, nine potential cations in actual water samples (Fe 3+ ,Al 3+ ,Cu 2+ ,Mg 2+ ,Ca 2+ ,Zn 2+ ,Pb 2+ ,Ni 2+ ,Ag + ) and 4 anions (Cl - ,NO3 - ,SO4 2- ,CO3 2- The peak current of 1μM DQ solution containing more than 100μM interfering substances was measured by SWV method. Figure 20 It can be seen from a that the interference of the tested pesticides on the DQ current is very small or negligible (Er<±5.0%). In addition, Figure 20 b It can be seen that, except for Fe 3+ and Ag + Besides significantly reducing the DQ reduction peak current, other ions showed only slight interference (Er < ± 5.0%). This shows that the modified electrode has good specificity in detecting DQ.

[0170] 2.5 Recovery of actual samples and comparison with high performance liquid chromatography (HPLC)

[0171] A P6-TATR / AB / GCE modified electrode was used to analyze DQ in river water, radish, and spinach samples. River water was collected from Huaxi River in Huaxi District, Guiyang City, Guizhou Province, China, and radish and spinach were purchased from a local farmers' market (with a small amount of soil attached to the roots). The river water was filtered through a 0.45μm filter membrane and prepared into BR buffer with a pH of 8.00. 30g of radish and spinach were each ground into a pulp, and the resulting slurry was centrifuged at 36000rpm for 8 minutes. 2.5mL of the supernatant was taken, diluted 100 times with BR buffer with a pH of 8.00, and filtered through a 0.45μm filter membrane. Using standard DQ solution, the above actual samples were prepared into four sample solutions with concentrations of 0.10μM, 0.50μM, and 1.00μM, respectively, and tested.

[0172] The SWV method failed to detect DQ in any real-world samples. Three spiked solutions at each concentration were then tested in parallel. As shown in Table 4, the sample recoveries ranged from 90.6% to 106.0%, demonstrating high accuracy. HPLC was used to further validate the feasibility of the SWV method for detection of DQ using the P6-TATR / AB / GCE electrode. Four replicates of each of the three real-world samples spiked at a concentration of 1 μM were tested in parallel. The results shown in Table 4 demonstrate good agreement between the two methods within a recovery range of 94.6% to 106.0%. F-tests and t-tests showed no significant differences in the means and variances between the two methods at the 95% confidence limit, confirming that the prepared P6-TATR / AB / GCE electrode possesses excellent precision and accuracy for detecting DQ using the SWV method.

[0173] Table 4 Comparison of the results of SWV and HPLC methods for detecting DQ in actual samples

[0174]

[0175] BDL:Below detection limit. a The critical tabulated value at 95% confidence interval is F=19.16(9.55), b The critical tabulated value at 95% confidence interval is t=2.57.

[0176] In summary, the novel composite modified electrode (P6-TATR / AB / GCE), prepared by doping the novel compound P6-TATR with AB, exhibits high sensitivity, strong selectivity, low detection limit, wide linear range, good reproducibility, high recovery, and excellent stability. This novel method involves doping a nitrogen-rich, electron-rich, and electrode-compatible hydrophobic structure with highly conductive and electrode-compatible acetylene black to form a composite electrode. When prepared as an electrode, this material exhibits highly sensitive detection of diquat. The P6-TATR / AB / GCE electrode exhibits excellent accuracy, durability, and anti-interference capabilities, ensuring reliable and specific detection of diquat in real-world samples.

Claims

1. A novel modified electrode of a pillar[6]arene derivative-acetylene black composite material, characterized in that: First, dihydroxy pillar[6]arene and tripolyindole derivatives were prepared. Then, dihydroxy pillar[6]arene and tripolyindole derivatives were bonded with each other in the presence of sodium hydride by the Williamson ether method to obtain a novel pillar[6]arene derivative. Then, the novel pillar[6]arene derivative was doped with acetylene black to prepare a dispersion system, which was drop-coated on the surface of a clean glassy carbon electrode to obtain a modified electrode P6-TATR / AB / GCE.

2. The method for preparing a modified electrode of a novel pillar[6]arene derivative-acetylene black composite material according to claim 1, characterized in that: The preparation method is carried out according to the following steps: (1) Synthesis of triindole derivatives: S1: Take 8-12 g of 2-indolone, add 25-35 mL of phosphorus oxychloride, and carry out a cyclization reaction at 95-105°C for 7-9 hours. Cool to room temperature, pour into ice water and stir continuously to produce a solid substance. After no solid substance is produced, adjust the pH to neutral with 5M sodium hydroxide solution, filter, wash with water 2-4 times, 25-35 mL each time, and then dry at 45-55°C for 4-6 hours to obtain a dry filter cake. Chromatography on a silica gel column is performed, and the eluent is a mixture of petroleum ether and ethyl acetate in a volume ratio of 4-6:

1. The chromatographic solution is collected, concentrated, and evaporated to dryness to obtain a solid substance, which is tripolyindole; S2: 1.8-2.2 g of tripolyindole, 550-650 mg of tetrabutylammonium bromide, and 5.8-6.5 g of potassium hydroxide were added to 35-45 mL of tetrahydrofuran solution, refluxed at 70-90 ° C under nitrogen for 25-35 min, 1.75-1.90 mL of 1-bromohexane was added, and refluxed for 11-13 hours. The mixture was cooled to room temperature, 25-35 mL of dichloromethane was added, and the mixture was extracted with water 2-4 times, 80-120 mL each time. The organic layer was collected and dried over 2.5-3.5 g of anhydrous Na2SO4, and concentrated. The concentrate was chromatographed on a silica gel column with 230-260 mL of a mixture of petroleum ether and ethyl acetate as the eluent, wherein the volume ratio of petroleum ether to ethyl acetate was 75-85:

1. The mixture was concentrated and evaporated to dryness to give a white solid, namely tri-N-hexyl tripolyindole; S3: Take 1.0-1.2g of tri-N-hexyltriindole and dissolve it in 18-22mL of chloroform at room temperature, slowly add 160-175μL of concentrated nitric acid and react for 1.8-2.2h, extract and wash with water 2-4 times, 25-35mL each time, collect the organic phase, dry the organic phase with 1.5-2.5g of anhydrous Na2SO4, and then concentrate to obtain a concentrate. The concentrate is chromatographed on a silica gel column, and the eluent is a mixture of petroleum ether and dichloromethane 280-320mL, the volume ratio of petroleum ether to dichloromethane is 1.8-2.2:1, collect the chromatographic liquid, concentrate and dry in a water bath to obtain an orange-red solid, take 1.4-1.6g of the orange-red solid, 2.2-2.6g of iron powder and 2.8-3.1g of ammonium chloride and add In a single-necked flask, 35-45 mL of aqueous ethanol and 18-22 mL of ethyl acetate were added, the volume ratio of the aqueous ethanol was 2.8-3.2: 1, refluxed under nitrogen for 20-25 h, cooled to room temperature, extracted 2-4 times with dichloromethane and water, each time using 25-35 mL of dichloromethane and 45-55 mL of water, and the organic phase was collected and dried over 1.8-2.5 g of anhydrous sodium sulfate. The organic phase was concentrated and evaporated to dryness, and the concentrate was chromatographed on a silica gel column with an eluent of 280-350 mL of a mixture of petroleum ether and ethyl acetate in a volume ratio of 1.8-2.2:

1. The mixture was concentrated and dried in a water bath to give a milky white solid, i.e., 3-aminotri-N-hexyltriindole. S4: 500-550 mg of 3-aminotri-N-hexyltriindole was dissolved in 4-6 mL of anhydrous tetrahydrofuran, followed by the addition of 345-375 μL of anhydrous triethylamine. The mixture was stirred in an ice bath for 5-15 min, and then 150-175 μL of 4-chloromethylbenzoyl chloride was slowly added. After reacting for 10-20 minutes, the reaction was quenched with 15-25 mL of saturated brine, and then extracted with dichloromethane. The mixture was washed three times with 15-25 mL of water each time. The organic phase was collected and dried over 2.5-3.5 g of anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to 0.2-1 mL. The mixture was purified by silica gel column chromatography, with the eluent being 80-120 mL of a mixed liquid of petroleum ether and dichloromethane in a volume ratio of 1:1.3-1.

8. The mixture was concentrated and evaporated to dryness to obtain a light yellow solid, which is the triindole derivative. The specific synthesis reaction formula is as follows: (2) Synthesis of dihydroxy pillar[6]arene: SS1: 1,4-dimethoxybenzene 6-7g, paraformaldehyde 1.2-1.5g, 1,2-dichloroethane 80-100mL and trifluoroacetic acid 4.5-5.5mL were placed in a single-necked flask, wherein the 1,2-dichloroethane was an anhydrous solvent. After reflux in an oil bath at 80-100°C under nitrogen protection for 1.8-2.2h, the mixture was cooled to room temperature and poured into 180-220mL of methanol. The solid was ultrasonically washed with 25-35mL of methanol and filtered. The filtrate was naturally dried to obtain the crude product of column [6]. SS2: The crude product from column [6] was dissolved in 45-55 mL of dichloromethane, and 9-11 mL of a methanol solution containing 1.8-2.0 g of cerium ammonium nitrate was slowly added dropwise. After reacting at room temperature for 1.8-2.2 h, 8-10 mL of a methanol solution containing 1.7-1.8 g of cerium ammonium nitrate was slowly added dropwise again. After reacting for 0.8-1.2 h, 90-110 mL of water was added for extraction. The organic phase was collected and dried with 2.5-3.5 g of anhydrous Na2SO4. The organic layer was then chromatographed on a silica gel column. The eluent was a mixed solution of petroleum ether and dichloromethane (280-320 mL). The volume ratio of petroleum ether to dichloromethane was 0.9-1.1:

2. The product was concentrated and evaporated to dryness to obtain a red solid P6O2. SS3: Take 850-900 mg of red solid P6O2 and dissolve it in 9-11 mL of dichloromethane. Add 9-11 mL of methanol solution containing 45-55 mg of sodium borohydride under nitrogen protection, and react until the solution becomes colorless and transparent. Quench with 4-6 mL of water and extract. Collect the organic phase, then dry the organic layer with 0.8-1.2 g of anhydrous Na2SO4, concentrate and evaporate to dryness to obtain a white solid, that is, dihydroxy column [6] aromatic hydrocarbon; The specific synthesis reaction formula is as follows: (3) Synthesis of novel pillar[6]arene derivatives: Take 140-160 mg of dihydroxy column [6] aromatic hydrocarbon and 15-17 mg of sodium hydride and mix them in 2.5-3.5 mL of N, N-dimethylformamide, which is an anhydrous solvent. Stir for 25-35 minutes under nitrogen atmosphere, add 300-350 mg of tripolyindole derivative, stir at 40-50 ° C for 20-25 hours, cool, extract with 8-12 mL of dichloromethane and 18-22 mL of saturated brine, and wash with reverse osmosis water for 3 minutes. -5 times of organic phase to remove residual N, N-dimethylformamide, the amount of reverse osmosis water used each time is 18-22 mL, the organic layer is collected, and the organic layer is dried with 0.8-1.2 g of anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and the concentrate is purified by silica gel column chromatography, the eluent is a mixed solution of petroleum ether and dichloromethane 45-55 mL, the petroleum ether and dichloromethane are in a volume ratio of 1.8-2.2:1, concentrated and evaporated to dryness to obtain a brown solid, that is, a new column [6] aromatic derivative; The specific synthesis reaction formula is as follows: (4) Preparation method of modified electrode: SSS1: Polish a glassy carbon electrode with 250-350μm Al2O3 for 1.5-3 minutes, then polish it with 40-60μm Al2O3 for 1.5-3 minutes. Then, ultrasonically clean it with ultrapure water for 2-4 times, each time for 8-15 seconds, and then ultrasonically clean it with anhydrous ethanol for 8-15 seconds. The electrode is then dried at room temperature to obtain a clean glassy carbon electrode for later use. SSS2: 2.5-3.5 mg of acetylene black was added to 0.8-1.5 mL of DMF and ultrasonically dispersed for 25-35 min. Then, 1.5-2.5 mg of the novel column[6] aromatic derivative was added and ultrasonically dispersed again for 25-35 min to obtain a P6-TATR / AB composite dispersion. SSS3: Use a pipette to transfer 8-15 μL of the P6-TATR / AB composite material dispersion and apply it dropwise on the clean surface of the glassy carbon electrode. After drying under an infrared lamp for 25-35 minutes, the electrode surface is rinsed with deionized water and allowed to air dry naturally to obtain the modified electrode P6-TATR / AB / GCE.

3. The method for preparing a modified electrode of a novel pillar [6] aromatic hydrocarbon derivative-acetylene black composite material according to claim 2, characterized in that: In the step (1), the synthesis method of the triindole derivative is: S1: Take 10 g of 2-indolone, add 30 mL of phosphorus oxychloride, and carry out cyclization reaction at 98°C for 8 hours. Cool to room temperature, pour into ice water and stir continuously to produce solid matter. After no solid matter is produced, adjust the pH to neutral with 5M sodium hydroxide solution, filter, wash with water 3 times, each time with 30 mL, and then dry at 50°C for 5 hours to obtain a dry filter cake. Chromatography on a silica gel column is performed, and the eluent is a mixture of petroleum ether and ethyl acetate in a volume ratio of 5:

1. The chromatographic solution is collected, concentrated and evaporated to dryness to obtain a solid matter, which is tripolyindole; S2: 2.0 g of triindole, 596 mg of tetrabutylammonium bromide, and 6.2 g of potassium hydroxide were added to 40 mL of tetrahydrofuran solution, and the mixture was refluxed at 80° C. under nitrogen for 30 min. 1-bromohexane 1.83 mL was added and refluxed for 12 hours. The mixture was cooled to room temperature, 30 mL of dichloromethane was added, and the mixture was extracted with water three times, 100 mL each time. The organic layer was collected and dried over 3 g of anhydrous Na2SO4, and concentrated to 0.2-1.0 mL. The concentrate was chromatographed on a silica gel column with 243 mL of a mixture of petroleum ether and ethyl acetate as the eluent, wherein the volume ratio of petroleum ether to ethyl acetate was 80:

1. The mixture was concentrated and evaporated to dryness to give a white solid, namely tri-N-hexyltriindole; S3: 1.12 g of tri-N-hexyltriindole was dissolved in 20 mL of chloroform at room temperature, 168 μL of concentrated nitric acid was slowly added dropwise and reacted for 2 h, the mixture was extracted and washed with water 3 times, 30 mL each time, the organic phase was collected, the organic phase was dried with 2 g of anhydrous Na2SO4, and then concentrated to 0.2-1.0 mL to obtain a concentrate, which was chromatographed on a silica gel column with an eluent of 300 mL of a mixture of petroleum ether and dichloromethane in a volume ratio of 2:

1. The chromatographic solution was collected and concentrated and dried in a water bath to obtain an orange-red solid. 1.51 g of the orange-red solid, 2.46 g of iron powder and 2.97 g of ammonium chloride were added Pour into a single-necked flask, add 40mL of ethanol aqueous solution and 20mL of ethyl acetate, the volume ratio of the ethanol aqueous solution is 3:1, reflux under nitrogen protection for 22h, cool to room temperature, extract with dichloromethane and water 3 times, each time the amount of dichloromethane is 30mL, the amount of water is 50mL, collect the organic phase, then dry the organic phase with 2g of anhydrous sodium sulfate, concentrate and evaporate to dryness, the concentrate is chromatographed on a silica gel column, the eluent is a mixture of petroleum ether and ethyl acetate 300mL, the volume ratio of petroleum ether and ethyl acetate is 2:1, concentrate and dry in a water bath to give a milky white solid, i.e., 3-aminotri-N-hexyltriindole; S4: Take 526 mg of 3-aminotri-N-hexyltriindole, dissolve it in 5 mL of anhydrous tetrahydrofuran, then add 366 μL of anhydrous triethylamine, stir in an ice bath for 10 minutes, and then slowly add 164 μL of 4-chloromethylbenzoyl chloride. After reacting for 15 minutes, quench the reaction with 20 mL of saturated brine, extract with dichloromethane, wash three times with water, add 20 mL of water each time, collect the organic phase, and then dry the organic phase with 3 g of anhydrous sodium sulfate, filter, and concentrate under reduced pressure to 0.2-1 mL. Purify by silica gel column chromatography, the eluent is 100 mL of a mixed liquid of petroleum ether and dichloromethane, and the volume ratio of petroleum ether and dichloromethane is 1:1.

5. Concentrate and evaporate to dryness to obtain a light yellow solid, which is the triindole derivative.

4. The method for preparing a modified electrode of a novel pillar [6] aromatic hydrocarbon derivative-acetylene black composite material according to claim 2, characterized in that: In the step (2), the synthesis method of dihydroxy pillar [6] aromatic hydrocarbons is: SS1: 6.21 g of 1,4-dimethoxybenzene, 1.35 g of paraformaldehyde, 90 mL of 1,2-dichloroethane and 5 mL of trifluoroacetic acid were placed in a single-necked flask, with the 1,2-dichloroethane being an anhydrous solvent. The mixture was refluxed in an oil bath at 90 °C for 2 h under nitrogen protection, then cooled to room temperature, poured into 200 mL of methanol, and filtered. The solid was ultrasonically washed with 30 mL of methanol and filtered. The filtrate was naturally dried to obtain the crude product of column [6]. SS2: The crude product from column [6] was dissolved in 50 mL of dichloromethane, and 10 mL of a methanol solution containing 1.90 g of cerium ammonium nitrate was slowly added dropwise. After reacting at room temperature for 2 h, 9 mL of a methanol solution containing 1.76 g of cerium ammonium nitrate was slowly added dropwise again. After reacting for 1 h, 100 mL of water was added for extraction. The organic phase was collected and dried over 3 g of anhydrous Na2SO4. The organic layer was then chromatographed on a silica gel column. The eluent was a mixed solution of 300 mL of petroleum ether and dichloromethane, with a volume ratio of 1:

2. The mixture was concentrated and evaporated to dryness to obtain a red solid P6O2. SS3: 872 mg of red solid P6O2 was dissolved in 10 mL of dichloromethane. Under nitrogen protection, 10 mL of methanol solution containing 51 mg of sodium borohydride was added. The reaction was continued until the solution became colorless and transparent. The solution was quenched with 5 mL of water and extracted. The organic phase was collected and dried with 1 g of anhydrous Na2SO4. The organic layer was concentrated and evaporated to dryness to obtain a white solid, i.e., dihydroxy columnar [6] aromatic hydrocarbon.

5. The method for preparing a modified electrode of a novel pillar [6] aromatic hydrocarbon derivative-acetylene black composite material according to claim 2, characterized in that: In the step (3), the synthesis method of the novel pillar [6] aromatic hydrocarbon derivative is: Take 150 mg of dihydroxy column [6] aromatic hydrocarbon and 16 mg of sodium hydride and mix them in 3 mL of N,N-dimethylformamide, wherein the N,N-dimethylformamide is an anhydrous solvent, stir for 30 minutes under a nitrogen atmosphere, add 330 mg of tripolyindole derivative, stir at 45 ° C for 22 hours, cool, extract with 10 mL of dichloromethane and 20 mL of saturated brine, wash the organic phase with reverse osmosis water 4 times to remove residual N,N-dimethylformamide, the amount of reverse osmosis water used each time is 20 mL, collect the organic layer, dry the organic layer with 1 g of anhydrous sodium sulfate, filter, concentrate under reduced pressure, and purify the concentrate by silica gel column chromatography, the eluent is 50 mL of a mixed solution of petroleum ether and dichloromethane, wherein the petroleum ether and dichloromethane are in a volume ratio of 2:1, concentrate and evaporate to dryness to obtain a brown solid, that is, a new column [6] aromatic hydrocarbon derivative.

6. The method for preparing a modified electrode of a novel pillar [6] aromatic hydrocarbon derivative-acetylene black composite material according to claim 2, characterized in that: In the step (4), the synthesis method of the novel pillar [6] aromatic derivative is: SSS1: Polish a glassy carbon electrode with 280-320 μm Al2O3 for 1.5-2.5 min, then polish it with 45-55 μm Al2O3 for 1.5-2.5 min, then ultrasonically clean it with ultrapure water for 2-4 times, each time for 8-12 seconds, and then ultrasonically clean it with anhydrous ethanol for 8-12 seconds. The electrode is then dried at room temperature to obtain a clean glassy carbon electrode for later use. SSS2: 2.8-3.2 mg of acetylene black was added to 0.8-1.2 mL of DMF and ultrasonically dispersed for 28-32 min. Then, 1.8-2.2 mg of the novel column[6] aromatic derivative was added and ultrasonically dispersed again for 28-32 min to obtain a P6-TATR / AB composite dispersion. SSS3: Use a pipette to transfer 8-12 μL of the P6-TATR / AB composite material dispersion and apply it on the clean surface of the glassy carbon electrode. After drying under an infrared lamp for 28-32 minutes, the electrode surface is washed with deionized water and allowed to air dry naturally to obtain the modified electrode P6-TATR / AB / GCE.

7. The method for preparing a modified electrode of a novel pillar [6] aromatic hydrocarbon derivative-acetylene black composite material according to claim 6, characterized in that: In the step (4), the preparation method of the modified electrode is: SSS1: Polish a glassy carbon electrode with 300 μm Al2O3 for 2 min, then with 50 μm Al2O3 for 2 min, then ultrasonically clean it with ultrapure water for 10 s three times, then ultrasonically clean it with anhydrous ethanol for 10 s. Dry the electrode at room temperature to obtain a clean glassy carbon electrode for later use. SSS2: 3 mg of acetylene black was added to 1 mL of DMF and dispersed with ultrasound for 30 min. Then 2 mg of the novel column[6]arene derivative was added and dispersed with ultrasound again for 30 min to obtain a P6-TATR / AB composite dispersion. SSS3: Use a pipette to transfer 10 μL of the P6-TATR / AB composite material dispersion and apply it dropwise on the clean surface of the glassy carbon electrode. After drying under an infrared lamp for 30 minutes, the electrode surface is washed with deionized water and allowed to air dry naturally to obtain the modified electrode P6-TATR / AB / GCE.

8. Use of a modified electrode of the novel pillar [6] aromatic hydrocarbon derivative-acetylene black composite material according to any one of claims 1 to 7 in electrochemical detection.

9. The use according to claim 8, characterized in that: The modified electrode can realize sensitive and selective analysis of positively charged analytes in aqueous solution; and the modified electrode can detect diquat.

Images