Preparation method and application of imidoCOF-carbon black composite material
By modifying the electrode with imide-based COF-carbon black composite material, the problems of insensitivity and susceptibility to contamination in electrochemical detection of dopamine were solved, achieving high sensitivity and anti-interference, and improving the effect of dopamine detection.
Patent Information
- Application Number
- CN202410977443.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-15
- Publication Date
- 2026-01-16
AI Technical Summary
Existing electrochemical methods are not sensitive enough for the detection of dopamine at the nanomolar level, and traditional electrodes are easily contaminated and the dopamine signal is masked by interfering molecules such as ascorbic acid and uric acid, resulting in low detection sensitivity.
An electrochemical sensor with high sensitivity and anti-interference properties was prepared by using an imide-based COF-carbon black composite material as the electrode modification material and loading imide-based COF onto the carbon black surface through a simple one-pot solvothermal method.
This method achieves a wide detection range, high sensitivity, and good anti-interference performance, improves the sensitivity and selectivity of dopamine detection, reduces the detection limit, and provides a simple and effective application method for electrochemical sensors.
Smart Images
Figure CN121343162A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrochemical sensing technology, and more specifically to an imide-based COF-carbon black composite material electrochemically modified electrode, its preparation method, and its application. Background Technology
[0002] Under typical physiological conditions, dopamine concentrations are at the nanomolar level, which current electrochemical methods are insufficiently sensitive for detection. Furthermore, traditional electrodes used for electrochemical detection are highly susceptible to contamination, further reducing detection sensitivity. Moreover, biological samples containing dopamine also contain various interfering molecules such as ascorbic acid and uric acid, which exhibit redox behavior similar to dopamine, thus masking the dopamine signal. Therefore, it is necessary to find suitable electrode modification materials to improve electrode sensitivity and specificity. Imidoyl covalent organic frameworks, as an emerging porous material, are crystalline porous frameworks prepared from pre-designed symmetric units. They possess excellent thermal stability, high specific surface area, and unique physicochemical properties, bringing enormous application potential to many fields, particularly electrochemistry, where they have attracted widespread attention. Summary of the Invention
[0003] The purpose of this invention is to provide a method for preparing an imide-based COF-carbon black composite material that uses readily available raw materials, has high sensitivity, and good anti-interference performance.
[0004] The technical solution adopted in this invention is a method for preparing an imide-based COF-carbon black composite material, comprising the following steps: 5,10,15,20-tetra(4-aminophenyl)porphyrin, naphthalenetetracarboxylic dianhydride, N-methylpyrrolidone, trimethylbenzene, isoquinoline, and carbon black are added to a Schlenk tube and placed in an ultrasonic machine to disperse the solution evenly. Then, under liquid nitrogen and flame-sealed conditions, the mixture undergoes three cycles of freezing / vacuuming / thawing. It is then placed in a forced-air drying oven and heated at 180°C for 5 days. After cooling, the precipitate is obtained by filtration. The precipitate is extracted using a Soxhlet method with tetrahydrofuran (24h), dichloromethane (24h), and methanol (24h). The extract is transferred to a drying oven and vacuum-dried at 100°C to obtain the imide-based COF-carbon black composite material.
[0005] Furthermore, in the above preparation method, the molar ratio of 5,10,15,20-tetra(4-aminophenyl)porphyrin:naphthalenetetracarboxylic dianhydride:carbon black is 1:2:30-60.
[0006] Furthermore, in the above preparation method, N-methylpyrrolidone is first subjected to drying and dehydration treatment.
[0007] Furthermore, in the above preparation method, after the mixed solution is evenly dispersed, it is subjected to three cycles of freezing / evacuation / thawing under liquid nitrogen and flame sealing conditions.
[0008] Furthermore, in the above preparation method, the mixture is heated at 180°C for 5 days in a forced-air drying oven.
[0009] Furthermore, in the above preparation method, the precipitate is obtained by filtration after cooling.
[0010] Furthermore, in the above preparation method, the precipitate is extracted using a Soxhlet method with tetrahydrofuran (24h), dichloromethane (24h), and methanol (24h).
[0011] The imide-based COF-carbon black composite material provided by this invention is used as an electrode modification material in the electrochemical detection of dopamine.
[0012] Further, the method is as follows: 2 mg of the composite material is dispersed in 1 mL of distilled water and ultrasonically dispersed to obtain a uniform dispersion. 6 μL of the dispersion is uniformly dropped onto a glassy carbon electrode and dried to obtain the working electrode. A platinum wire electrode is used as the control electrode, and a saturated calomel electrode is used as the reference electrode.
[0013] Furthermore, the test solution was a dopamine-containing dipotassium hydrogen phosphate and potassium dihydrogen phosphate buffer solution in PBS, with a dopamine concentration of 2.49 μM-62.11 μM. The electrochemical reduction voltage was -0.2-0.4 V, the scan rate was 0.02-0.2 V / s, and the number of cycles was 10-100.
[0014] The beneficial effects of this invention are as follows: The imide-based COF-carbon black composite material prepared by this invention uses a simple one-pot solvothermal method to load imide-based COF onto the surface of carbon black. Subsequently, this composite material is used as an electrode modification material for electrochemical detection of dopamine, exhibiting a wide detection range, high sensitivity, and good anti-interference performance. The imide-based COF-carbon black composite material electrochemical sensor electrode modification material prepared by this invention has a simple experimental method and easily achievable experimental conditions, effectively improving the active sites and conductivity of the sensor electrode material, thereby improving detection sensitivity and anti-interference performance, reducing the detection limit, and exhibiting high selectivity and stability. This provides a new method for the practical application of electrochemical sensors in the detection of dopamine. Attached Figure Description
[0015] Figure 1 SEM image of the imide-based COF-carbon black composite material with a carbon black content of 30% prepared in this invention;
[0016] Figure 2FT-IR spectra of 5,10,15,20-tetra(4-aminophenyl)porphyrin, naphthalenetetracarboxylic dianhydride, and imide-based COF-carbon black composites with different carbon black contents prepared in this invention.
[0017] Figure 3 SWV curves of bare electrodes and electrodes modified with imide-based COF-carbon black composite materials with different carbon black contents prepared in this invention, measured in 0.1M PBS (pH=7.0) containing 50μM dopamine;
[0018] Figure 4 Images of different concentrations of dopamine were detected using differential pulse voltammetry on an electrochemical workstation with the carbon black content of 30% imide-based COF-carbon black composite material prepared by the present invention. (a) is the DPV curve, and (b) is the linear relationship between peak current and dopamine concentration.
[0019] Figure 5 The graph shows the anti-interference performance of the imide-based COF-carbon black composite material with a carbon black content of 30% prepared using the present invention in the electrochemical detection of dopamine on an electrochemical workstation. Detailed Implementation
[0020] The technical solution of the present invention will be further described below through specific embodiments.
[0021] Example 1:
[0022] Add 5,10,15,20-tetra(4-aminophenyl)porphyrin (27 mg, 0.02 mmol), naphthalenetetracarboxylic dianhydride (21.4 mg, 0.04 mmol), N-methylpyrrolidone (0.5 ml), thiol (0.5 ml), isoquinoline (0.08 ml), and carbon black (7.6 mg, 0.63 mmol) to a Schlenk tube (10 ml) and sonicate to disperse the solution evenly. Then, under liquid nitrogen and flame sealing conditions, the mixture was subjected to three cycles of freezing / vacuuming / thawing. After that, it was placed in a forced-air drying oven and heated at 180°C for 5 days. After cooling, the precipitate was obtained by filtration and then extracted with tetrahydrofuran (24 h), dichloromethane (24 h), and methanol (24 h) using the Soxhlet method. The extract was dried under vacuum at 100°C to obtain a black powder.
[0023] Scanning electron microscopy (SEM) revealed that the composite material in Example 1 exhibited a morphology of small spheres clustered together, with carbon black particles uniformly distributed throughout the material. Figure 1 As shown.
[0024] The presence of imide vibrational bands was confirmed by FT-IR spectroscopy, with C=O stretching vibrations appearing near 1666 cm⁻¹ and 1708 cm⁻¹, and CNC stretching vibrations near 1332 cm⁻¹. Figure 2 As shown.
[0025] Example 2:
[0026] Add 5,10,15,20-tetra(4-aminophenyl)porphyrin (27 mg, 0.02 mmol), naphthalenetetracarboxylic dianhydride (21.4 mg, 0.04 mmol), N-methylpyrrolidone (0.5 ml), trimethylbenzene (0.5 ml), isoquinoline (0.08 ml), and carbon black (11.3 mg, 0.94 mmol) to a Schlenk tube (10 ml) and sonicate to disperse the solution evenly. Then, under liquid nitrogen and flame sealing conditions, the mixture was subjected to three cycles of freezing / vacuuming / thawing. After that, it was placed in a forced-air drying oven and heated at 180°C for 5 days. After cooling, the precipitate was obtained by filtration and then extracted with tetrahydrofuran (24 h), dichloromethane (24 h), and methanol (24 h) using the Soxhlet method. The extract was dried under vacuum at 100°C to obtain a black powder.
[0027] Example 3:
[0028] 5,10,15,20-tetra(4-aminophenyl)porphyrin (27 mg, 0.02 mmol), naphthalenetetracarboxylic dianhydride (21.4 mg, 0.04 mmol), N-methylpyrrolidone (0.5 ml), trimethylbenzene (0.5 ml), isoquinoline (0.08 ml), and carbon black (15.2 mg, 1.26 mmol) were added to a Schlenk tube (10 ml) and the solution was sonicated to ensure uniform dispersion. The mixture was then subjected to a three-cycle freeze / vacuum / thaw cycle under liquid nitrogen and flame sealing conditions. Afterward, it was placed in a forced-air drying oven and heated at 180°C for 5 days. Upon cooling, the precipitate was obtained by filtration and then extracted using a Soxhlet method with tetrahydrofuran (24 h), dichloromethane (24 h), and methanol (24 h). The extract was dried under vacuum at 100°C to obtain a black powder.
[0029] Example 4:
[0030] The imide-based COF-carbon black composite material obtained in Example 2 was used as an electrode modification material in the electrochemical detection of dopamine. 2 mg of the composite material was dispersed in 1 mL of distilled water and ultrasonically dispersed to obtain a uniform dispersion. 6 μL of the dispersion was uniformly added dropwise onto a glassy carbon electrode, and after drying, the working electrode was obtained. A platinum wire electrode was used as the control electrode, and a saturated calomel electrode was used as the reference electrode. The concentration of the dipotassium hydrogen phosphate and potassium dihydrogen phosphate buffer solution (pH = 7) was 0.1 M, the dopamine concentration was 100 μM, and the scan rate was 0.02–0.2 V / s. With increasing scan rate, the currents of the oxidation and reduction peaks gradually increased.
[0031] Example 5:
[0032] The imide-based COF-carbon black composite material obtained in Example 2 was used as an electrode modification material in the electrochemical detection of dopamine. 2 mg of the composite material was dispersed in 1 mL of distilled water and ultrasonically dispersed to obtain a uniform dispersion. 6 μL of the dispersion was uniformly added dropwise onto a glassy carbon electrode, and after drying, the working electrode was obtained. A platinum wire electrode was used as the control electrode, and a saturated calomel electrode was used as the reference electrode. When 50 μM of dopamine was added to a 0.1 M potassium dihydrogen phosphate buffer solution (pH = 7), the peak current increased significantly. When 1 mM of interfering substances (Alanine, KCl, L-histidine, NaCl, Tryptophan, Glycine, CaCl2, FeCl3) were added, the current remained essentially unchanged. Then, when 50 μM of dopamine was added again, the peak current increased significantly again.
[0033] Example 6:
[0034] The imide-based COF-carbon black composite material obtained in Example 2 was used as an electrode modification material in the electrochemical detection of dopamine. 2 mg of the composite material was dispersed in 1 mL of distilled water and ultrasonically dispersed to obtain a uniform dispersion. 6 μL of the dispersion was uniformly added dropwise onto a glassy carbon electrode, and after drying, a working electrode was obtained. A platinum wire electrode was used as the control electrode, and a saturated calomel electrode as the reference electrode. A certain amount of river water, seawater, and tap water were centrifuged to remove impurities. The supernatant was used to prepare a 0.1 M potassium dihydrogen phosphate buffer solution (pH = 7). Dopamine was then added to the prepared buffer solution to achieve a concentration of 50 μM. The SWV test was performed three times, and the test data were substituted into a linear equation to calculate the theoretical concentration. The RSD was found to be < 3.8, indicating that the modified electrode has great potential for the detection of real dopamine samples.
Claims
1. A method for preparing imide COF-carbon black composite materials, characterized in that, The method comprises the following steps: adding 5,10,15,20-tetrakis(4-aminophenyl) porphyrin, naphthalene tetracarboxylic dianhydride, N-methyl pyrrolidone, mesitylene, isoquinoline and carbon black in a Schlenk tube, and placing the solution in an ultrasonic machine to uniformly disperse the solution. Then, under the conditions of liquid nitrogen and flame sealing, after the mixed solution is subjected to three cycles of freezing / vacuumizing / thawing, the mixed solution is placed in a blast drying oven and heated at 180 DEG C for 5 days. After cooling, the precipitate is obtained by suction filtration. Then, the precipitate is extracted by Soxhlet method using tetrahydrofuran (24 hours), dichloromethane (24 hours) and methanol (24 hours), and the extract is dried at 100 DEG C under vacuum to obtain the imide COF-carbon black composite material.
2. The production method according to claim 1, characterized by, The molar ratio of 5,10,15,20-tetrakis(4-aminophenyl) porphyrin, naphthalene tetracarboxylic dianhydride and carbon black is 1:2:30-60.
3. The preparation method according to claim 1, characterized in that, The N-methyl pyrrolidone is subjected to drying and water removal treatment.
4. The production method according to claim 1, characterized by, After the mixed solution is uniformly dispersed, the mixed solution is subjected to three cycles of freezing / vacuumizing / thawing under the conditions of liquid nitrogen and flame sealing.
5. The production method according to claim 1 or 4, characterized by, The mixed solution is heated at 180 DEG C for 5 days in a blast drying oven.
6. The production method according to claim 1 or 5, characterized by, After cooling, the precipitate is obtained by suction filtration.
7. The production method according to claim 1 or 6, characterized by, The precipitate is extracted by Soxhlet method using tetrahydrofuran (24 hours), dichloromethane (24 hours) and methanol (24 hours).
8. Application of the imide COF-carbon black composite material prepared by the method of claim 1 to electrochemical detection of dopamine as electrode modification material.
9. Use according to claim 8, characterized in that, The method is as follows: 2 mg of the imide COF-carbon black composite material is dispersed in 1 mL of distilled water, and ultrasonic dispersion is performed to obtain a uniform dispersion liquid. 6 microliters of the dispersion liquid is uniformly dropped on a glassy carbon electrode, and after drying, a working electrode is obtained. A platinum wire electrode is used as a counter electrode, and a saturated calomel electrode is used as a reference electrode.
10. Use according to claim 8, characterized in that, The to-be-detected solution is a dopamine potassium phosphate buffer solution PBS, the concentration of dopamine is 2.49 μM-62.11 μM, the voltage of electrochemical reduction is-0.2-0.4 V, the scanning rate is 0.02-0.2 V / s, and the cycle number is 10-100 cycles.