A chemical modified electrode for detecting furazolidone and an electrochemical detection method thereof
By using nitrogen-doped porous carbon materials and polydopamine-modified screen-printed carbon electrodes, the problems of easy passivation and poor repeatability of traditional electrodes have been solved, enabling rapid and sensitive detection of furazolidone, which is suitable for on-site detection of animal-derived foods.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHONGKAI UNIV OF AGRI & ENG
- Filing Date
- 2023-10-16
- Publication Date
- 2026-06-23
Abstract
Description
Technical Field
[0001] This invention relates to the field of furazolidone detection technology, specifically to a chemically modified electrode for detecting furazolidone and its electrochemical detection method. Background Technology
[0002] Furazolidone is an organic compound with the chemical formula C8H7N3O5. It is a nitrofuran antibiotic used to treat gastrointestinal disorders such as dysentery, enteritis, and gastric ulcers caused by bacteria and protozoa. Furazolidone is a broad-spectrum antibacterial drug that inhibits common Gram-negative and Gram-positive bacteria.
[0003] Currently, the main methods for determining furazolidone include spectrophotometry, high-performance liquid chromatography (HPLC), and electrochemical methods. Spectrophotometry is simple to operate but has low sensitivity; HPLC is accurate and sensitive, but the instruments are expensive and highly specialized, making it difficult to perform on-site analysis; electrochemical methods have advantages such as simple operation, rapid sensitivity, and low cost, but existing electrochemical analysis methods for furazolidone are mainly based on traditional electrodes such as glassy carbon electrodes or gold electrodes. These electrodes are prone to passivation, requiring polishing before each use, and have poor repeatability. Therefore, we propose a chemically modified electrode for detecting furazolidone and its electrochemical detection method. Summary of the Invention
[0004] To address the shortcomings of existing technologies, this invention provides a chemically modified electrode for detecting furazolidone and its electrochemical detection method, thus solving the problems mentioned in the background section.
[0005] To achieve the above objectives, the present invention provides a chemically modified electrode for detecting furazolidone and its electrochemical detection method, comprising the following specific steps:
[0006] (1) Preparation of Longan Carbon
[0007] Take longan shells and wash them thoroughly with distilled water. After washing, place them in a constant temperature electric oven at 110℃ and dry for 4 hours until constant weight. Then, crush them with a food processor and pass them through a 40-mesh sieve. Finally, place the obtained longan charcoal powder in a dry sealed bag for later use.
[0008] (2) Preparation of nitrogen-doped longan carbon materials
[0009] Urea and chitosan with high nitrogen content were selected as external nitrogen sources, and KOH was used as an activator. 1g of longan carbon powder was mixed with urea, chitosan and KOH in a ratio of 1:1.5:1.5:2 in a solid phase and then ground thoroughly to make them uniformly mixed together to obtain a mixture.
[0010] The mixture was placed in an alumina magnetic boat and calcined in a tube furnace. Then, it was heated to 400°C at a heating rate of 2°C / min and held for 60 min to allow the urea and chitosan to fully melt and uniformly penetrate into the pores of longan carbon along with KOH. Then, it was heated to 800°C at a rate of 3°C / min and held for 120 min before being cooled to room temperature. The crude NCs product was then removed.
[0011] The crude NCs product was washed with 0.1 mol / L hydrochloric acid until the solution became neutral, then rinsed thoroughly with ultrapure water, and finally filtered and dried to obtain the finished NCs product, which was then placed in a dehumidifying cabinet for later use.
[0012] (3) Preparation of nitrogen-doped longan carbon-polydopamine materials
[0013] Add 20 mg of NCs to 20 mL of phosphate buffer, stir, and then pass N2 through for 10 min. Then add 15 mg of dopamine hydrochloride, sonicate in an ice-water bath for 10 min, and stir the mixture at 70°C for 3 h to obtain a uniformly mixed NCs-PDA dispersion.
[0014] The NCs-PDA dispersion was then filtered and washed three times with ultrapure water, and then dried to obtain NCs-PDA solid powder.
[0015] Furthermore, the following specific steps are also included:
[0016] (4) Preparation of NCs-PDA / SPCE modified electrode
[0017] 2 mg of NCs-PDA was ultrasonically dispersed in 1 mL of 0.05 wt% Nafion aqueous solution. The NCs-PDA dispersion in solution 5 was then dropped onto the SPCE surface, and the electrode was placed in a cool and ventilated place.
[0018] After drying at room temperature for 30 minutes, rinse the electrode surface with ultrapure water and air dry to obtain NCs-PDA / SPCE;
[0019] (5) Electrochemical detection of FZD
[0020] 30 μL of 0.1 mol / L PBS solution containing FZD was dropped onto the surface of NCs-PDA / SPCE. After standing for 90 s, differential pulse voltammetry was performed at a potential of -0.1 to -0.7 V and a scan rate of 100 mV / s to obtain the relationship curve between the response current value (I) and the potential (E).
[0021] Furthermore, the following specific steps are also included:
[0022] (6) Characterization of NCs-PDA / SPCE
[0023] A. Cyclic voltammetry (CV): 30 μL of 5 mmol / L K3Fe(CN)6 solution is dropped onto the surface of SPCE or modified electrode. Cyclic voltammetry is used to scan one cycle at a potential of -0.5 to 0.8 V and a scan rate of 50 mV / s to obtain the electrochemical response of K3Fe(CN)6 on the electrode.
[0024] B. Electrochemical impedance spectroscopy (EIS): 30 μL of 5 mmol / L K3Fe(CN)6 solution is dropped onto the surface of SPCE or modified electrode. The electrode is characterized by AC impedance spectroscopy at an amplitude of 5 mV and a frequency range of 0.1–100,000 Hz to obtain the AC impedance spectrum.
[0025] Furthermore, in the preparation process of nitrogen-doped longan carbon material in step (2), nitrogen gas needs to be purged for 20 minutes to remove oxygen before calcination is heated.
[0026] Furthermore, in step (2) of the preparation of nitrogen-doped longan carbon material, the entire calcination process must be carried out under an N2 atmosphere.
[0027] Furthermore, in step (3) of the preparation of nitrogen-doped longan carbon material, the pH of the phosphate buffer solution is 8.5.
[0028] Furthermore, in step (5) of the electrochemical detection of FZD, the pH of the PBS solution is 7.0.
[0029] This invention provides a chemically modified electrode for detecting furazolidone and its electrochemical detection method, which has the following beneficial effects: The chemically modified electrode and its electrochemical detection method for detecting furazolidone use longan shell as a carbon source and chitosan and urea as nitrogen sources. A nitrogen-doped porous carbon material (NCs) is prepared by high-temperature carbonization. Urea and chitosan with high nitrogen content are used as external nitrogen sources during the preparation of NCs, and KOH is selected as an activator. KOH can react with the carbon-based components of biomass raw materials to generate K2CO3, which then thermally decomposes to generate CO2, facilitating the formation of a porous structure. The nitrogen-doped porous carbon material (NCs) is combined with polydopamine (PDA) and a portable, disposable screen-printed carbon electrode (SPCE) to prepare an electrochemically modified electrode for determining furazolidone, NCs-PDA / SPCE. A rapid electrochemical detection method for determining furazolidone in animal-derived foods based on this modified electrode is also established. The modified material NCs-PDA is simple, readily available, and low-cost. SPCE is compact and portable, requiring no pretreatment processes such as cleaning or polishing, and can be rapidly modified in batches with a sample volume of only 30 μL. It is suitable for the rapid on-site detection of furazolidone in animal-derived foods, providing technical support for monitoring the quality and safety of animal-derived foods. Furthermore, NCs have abundant porous structures, providing a good channel for furazolidone to reach the electrode surface from the solution, which is conducive to charge transfer at the electrode-solution interface. At the same time, the active groups in NCs can interact with furazolidone through π-π bonds, hydrogen bonds, and electrostatic interactions. In addition, the abundant active groups on the PDA surface are conducive to furazolidone reaching the electrode surface and reacting. The synergistic effect of NCs and PDA composites has a significant catalytic effect on the electrochemical reduction of furazolidone, significantly improving the charge transfer rate and significantly enhancing the response current of furazolidone on NCs-PDA / SPCE. Detailed Implementation
[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to specific embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0031] A chemically modified electrode for detecting furazolidone and its electrochemical detection method, comprising the following specific steps:
[0032] (1) Preparation of Longan Carbon
[0033] Take longan shells and wash them thoroughly with distilled water. After washing, place them in a constant temperature electric oven at 110℃ and dry for 4 hours until constant weight. Then, crush them with a food processor and pass them through a 40-mesh sieve. Finally, place the obtained longan charcoal powder in a dry sealed bag for later use.
[0034] (2) Preparation of nitrogen-doped longan carbon materials
[0035] Urea and chitosan with high nitrogen content were selected as external nitrogen sources, and KOH was used as an activator. 1g of longan carbon powder was mixed with urea, chitosan and KOH in a ratio of 1:1.5:1.5:2 in a solid phase and then ground thoroughly to make them uniformly mixed together to obtain a mixture.
[0036] The mixture was placed in an alumina magnetic boat and calcined in a tube furnace. Then, it was heated to 400°C at a heating rate of 2°C / min and held for 60 min to allow the urea and chitosan to fully melt and uniformly penetrate into the pores of longan carbon along with KOH. Then, it was heated to 800°C at a rate of 3°C / min and held for 120 min before being cooled to room temperature. The crude NCs product was then removed.
[0037] The crude NCs product was washed with 0.1 mol / L hydrochloric acid until the solution became neutral, then rinsed thoroughly with ultrapure water, and finally filtered and dried to obtain the finished NCs product, which was then placed in a dehumidifying cabinet for later use.
[0038] (3) Preparation of nitrogen-doped longan carbon-polydopamine materials
[0039] Add 20 mg of NCs to 20 mL of phosphate buffer, stir, and then pass N2 through for 10 min. Then add 15 mg of dopamine hydrochloride, sonicate in an ice-water bath for 10 min, and stir the mixture at 70°C for 3 h to obtain a uniformly mixed NCs-PDA dispersion.
[0040] The NCs-PDA dispersion was then filtered and washed three times with ultrapure water, and then dried to obtain NCs-PDA solid powder.
[0041] It also includes the following specific steps:
[0042] (4) Preparation of NCs-PDA / SPCE modified electrode
[0043] 2 mg of NCs-PDA was ultrasonically dispersed in 1 mL of 0.05 wt% Nafion aqueous solution. The NCs-PDA dispersion in solution 5 was then dropped onto the SPCE surface, and the electrode was placed in a cool and ventilated place.
[0044] After drying at room temperature for 30 minutes, rinse the electrode surface with ultrapure water and air dry to obtain NCs-PDA / SPCE;
[0045] (5) Electrochemical detection of FZD
[0046] 30 μL of 0.1 mol / L PBS solution containing FZD was dropped onto the surface of NCs-PDA / SPCE. After standing for 90 s, differential pulse voltammetry was performed at a potential of -0.1 to -0.7 V and a scan rate of 100 mV / s to obtain the relationship curve between the response current value (I) and the potential (E).
[0047] It also includes the following specific steps:
[0048] (6) Characterization of NCs-PDA / SPCE
[0049] A. Cyclic voltammetry (CV): 30 μL of 5 mmol / L K3Fe(CN)6 solution is dropped onto the surface of SPCE or modified electrode. Cyclic voltammetry is used to scan one cycle at a potential of -0.5 to 0.8 V and a scan rate of 50 mV / s to obtain the electrochemical response of K3Fe(CN)6 on the electrode.
[0050] B. Electrochemical impedance spectroscopy (EIS): 30 μL of 5 mmol / L K3Fe(CN)6 solution is dropped onto the surface of SPCE or modified electrode. The electrode is characterized by AC impedance spectroscopy at an amplitude of 5 mV and a frequency range of 0.1–100,000 Hz to obtain the AC impedance spectrum.
[0051] In step (2), during the preparation of nitrogen-doped longan carbon material, nitrogen gas needs to be purged for 20 minutes before heating during calcination. In step (2), during the preparation of nitrogen-doped longan carbon material, the entire calcination process must maintain an N2 atmosphere. In step (3), during the preparation of nitrogen-doped longan carbon material, the pH of the phosphate buffer solution is 8.5. In step (5), during the electrochemical detection of FZD, the pH of the PBS solution is 7.0.
[0052] Example 1
[0053] Chicken samples were cut into small pieces and pulverized evenly. 2.0 g (±0.01 g) of the chicken sample was then weighed into a 50 mL centrifuge tube, 10 mL of ethyl acetate was added, and the mixture was extracted by sonication for 10 min. After centrifugation at 10000 r / min for 10 min, the supernatant was collected. This process was repeated once, and the supernatants were combined. 10 mL of n-hexane was added to remove fat. After centrifugation, the lower layer was collected and rotary evaporated at 30 °C until the ethyl acetate was completely removed. 5 mL of pH 7.0 PBS was added to dissolve the effluent before testing. During testing, 30 μL of the chicken sample solution was dropped onto the surface of an NCs-PDA / SPCE. After standing for 90 s, a differential pulse voltammetry scan was performed at a potential of -0.1 to -0.7 V and a scan rate of 100 mV / s. The relationship curve between the response current (I) and the potential (E) was obtained, which allowed for the detection of FZD in the chicken sample.
[0054] Example 2
[0055] Cut the beef sample into small pieces and grind it evenly. Then weigh 2.0 g (±0.01 g) of the beef sample into a 50 mL centrifuge tube, add 10 mL of ethyl acetate, and extract by sonication for 10 min. Centrifuge at 10000 r / min for 10 min and take out the supernatant. Repeat the operation once and combine the supernatants. Evaporate at 30℃ until the ethyl acetate is completely removed. Add 5 mL of pH 7.0 PBS to dissolve and then test. For detection, drop 30 μL of the beef sample solution to be tested onto the surface of NCs-PDA / SPCE. After standing for 90 s, perform differential pulse voltammetry scanning at a potential of -0.1 to -0.7 V and a scan rate of 100 mV / s to obtain the relationship curve between the response current value (I) and the potential (E). The FZD contained in the beef sample can then be detected.
[0056] Example 3
[0057] Weigh 3.0 g (±0.01 g) of milk sample into a 50 mL centrifuge tube, add 30 mL of pH 7.0 PBS, sonicate for 10 min, centrifuge at 10000 r / min for 10 min, take out the supernatant, repeat the centrifugation once for the remaining liquid, and combine the supernatants for testing; during detection, drop 30 μL of the milk sample solution to be tested onto the surface of NCs-PDA / SPCE, let stand for 90 s, and then perform differential pulse voltammetry scanning at a potential of -0.1 to -0.7 V and a scan rate of 100 mV / s to obtain the relationship curve between the response current value (I) and the potential (E), which can be used to detect FZD in the milk sample.
[0058] Example 4
[0059] Weigh 3.0 g (±0.01 g) of honey sample into a 50 mL centrifuge tube, add 30 mL of pH 7.0 PBS to dissolve, centrifuge at 10000 r / min for 10 min, and take the supernatant for testing; during detection, drop 30 μL of the honey sample solution to be tested onto the surface of NCs-PDA / SPCE, let it stand for 90 s, and then perform differential pulse voltammetry scanning at a potential of -0.1 to -0.7 V and a scan rate of 100 mV / s to obtain the relationship curve between the response current value (I) and the potential (E), which can be used to detect FZD in the honey sample.
[0060] In summary, the chemically modified electrode for detecting furazolidone and its electrochemical detection method include the following specific steps:
[0061] (1) Preparation of Longan Carbon: Take longan shells and wash them thoroughly with distilled water. After washing, place them in a constant temperature electric oven at 110℃ and dry for 4 hours until constant weight. Then, crush them with a food processor and pass them through a 40-mesh sieve. Finally, place the prepared longan carbon powder in a dry sealed bag for later use.
[0062] (2) Preparation of nitrogen-doped longan carbon material: Urea and chitosan with high nitrogen content were selected as external nitrogen sources, and KOH was used as an activator. 1g of longan carbon powder was mixed with urea, chitosan and KOH in a ratio of 1:1.5:1.5:2 in a solid phase and ground thoroughly to ensure uniform mixing. The mixture was placed in an alumina magnetic boat and calcined in a tube furnace. Before heating, nitrogen gas was purged for 20min to remove oxygen. Then, the mixture was heated at a heating rate of 2℃ / min. The temperature was raised to 400℃ and held for 60 minutes to allow urea and chitosan to fully melt and penetrate evenly into the pores of longan carbon along with KOH. Then, the temperature was increased to 800℃ at a rate of 3℃ / min and held for 120 minutes before cooling to room temperature. The crude NCs product was then removed. The entire calcination process required the maintenance of an N2 atmosphere. The crude NCs product was then rinsed with 0.1mol / L hydrochloric acid until the solution became neutral. It was then thoroughly rinsed with ultrapure water and finally filtered and dried to obtain the finished NCs product, which was then placed in a dehumidifying cabinet for later use.
[0063] (3) Preparation of nitrogen-doped longan carbon-polydopamine material: 20 mg of NCs was added to 20 mL of phosphate buffer solution with pH = 8.5. After stirring, N2 was passed through for 10 min. Then, 15 mg of dopamine hydrochloride was added and sonicated in an ice-water bath for 10 min. The mixed solution was stirred at 70°C for 3 h to obtain a uniformly mixed NCs-PDA dispersion. The NCs-PDA dispersion was then filtered and washed three times with ultrapure water, and then dried to obtain NCs-PDA solid powder.
[0064] (4) Preparation of NCs-PDA / SPCE modified electrode: 2 mg of NCs-PDA was ultrasonically dispersed in 1 mL of 0.05 wt% Nafion aqueous solution. The NCs-PDA dispersion in the solution was drop-coated onto the SPCE surface. The electrode was then placed in a cool and ventilated place. After drying at room temperature for 30 min, the electrode surface was rinsed with ultrapure water and then dried to obtain NCs-PDA / SPCE.
[0065] (5) Electrochemical detection of FZD: 30 μL of 0.1 mol / L PBS solution containing FZD was dropped onto the surface of NCs-PDA / SPCE, where the pH of the PBS solution was 7.0. After standing for 90 s, differential pulse voltammetry was performed at a potential of -0.1 to -0.7 V and a scan rate of 100 mV / s to obtain the relationship curve between the response current value (I) and the potential (E).
[0066] (6) Characterization of NCs-PDA / SPCE
[0067] A. Cyclic voltammetry (CV): 30 μL of 5 mmol / L K3Fe(CN)6 solution is dropped onto the surface of SPCE or modified electrode. Cyclic voltammetry is used to scan one cycle at a potential of -0.5 to 0.8 V and a scan rate of 50 mV / s to obtain the electrochemical response of K3Fe(CN)6 on the electrode.
[0068] B. Electrochemical impedance spectroscopy (EIS): 30 μL of 5 mmol / L K3Fe(CN)6 solution is dropped onto the surface of SPCE or modified electrode. The electrode is characterized by AC impedance spectroscopy at an amplitude of 5 mV and a frequency range of 0.1–100,000 Hz to obtain the AC impedance spectrum.
[0069] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. An electrochemical detection method for furazolidone, characterized in that, The specific steps include the following: (1) Preparation of Longan Carbon Take longan shells and wash them thoroughly with distilled water. After washing, place them in a constant temperature electric oven at 110 ℃ and dry for 4 hours until constant weight. Then, crush them with a food processor and pass them through a 40-mesh sieve. Finally, place the obtained longan charcoal powder in a dry sealed bag for later use. (2) Preparation of nitrogen-doped longan carbon (NCs) materials Urea and chitosan with high nitrogen content were selected as external nitrogen sources, and KOH was used as an activator. 1 g of longan carbon powder was mixed with urea, chitosan and KOH in a ratio of 1:1.5:1.5:2 in a solid phase and then ground thoroughly to make them uniformly mixed together to obtain a mixture. The mixture was placed in an alumina magnetic boat and calcined in a tube furnace. Then, it was heated to 400 °C at a heating rate of 2 °C / min and held for 60 min to allow the urea and chitosan to fully melt and uniformly penetrate into the pores of longan carbon along with KOH. Then, it was heated to 800 °C at a rate of 3 °C / min and held for 120 min before being cooled to room temperature. The crude NCs product was then removed. The crude NCs product was washed with 0.1 mol / L hydrochloric acid until the solution became neutral, then rinsed thoroughly with ultrapure water, and finally filtered and dried to obtain the finished NCs product, which was then placed in a dehumidifying cabinet for later use. (3) Preparation of nitrogen-doped longan carbon-polydopamine materials Add 20 mg of NCs to 20 mL of phosphate buffer, stir, and then pass N2 through for 10 min. Then add 15 mg of dopamine hydrochloride, sonicate in an ice-water bath for 10 min, and stir the mixture at 70 ℃ for 3 h to obtain a well-mixed NCs-PDA dispersion. The NCs-PDA dispersion was then filtered and washed three times with ultrapure water, and then dried to obtain NCs-PDA solid powder. (4) Preparation of NCs-PDA / SPCE modified electrode 2 mg of NCs-PDA was ultrasonically dispersed in 1 mL of 0.05 wt% Nafion aqueous solution. The NCs-PDA dispersion from step (3) was drop-coated onto the SPCE surface, and then the electrode was placed in a cool and ventilated place. After drying at room temperature for 30 minutes, rinse the electrode surface with ultrapure water and air dry to obtain NCs-PDA / SPCE; (5) Electrochemical detection of FZD 30 µL of 0.1 mol / L PBS solution containing FZD was dropped onto the surface of NCs-PDA / SPCE. After standing for 90 s, differential pulse voltammetry was performed at a potential of -0.1 to -0.7 V and a scan rate of 100 mV / s to obtain the relationship curve between the response current (I) and the potential (E).
2. The electrochemical detection method for furazolidone according to claim 1, characterized in that: In the preparation of nitrogen-doped longan carbon material in step (2), nitrogen gas needs to be passed through for 20 minutes to remove oxygen before calcination is heated.
3. The electrochemical detection method for furazolidone according to claim 1, characterized in that: In step (2), during the preparation of nitrogen-doped longan carbon material, the entire calcination process must be carried out under an N2 atmosphere.
4. The electrochemical detection method for furazolidone according to claim 1, characterized in that: In step (3), during the preparation of nitrogen-doped longan carbon material, the pH of the phosphate buffer solution is 8.
5.
5. The electrochemical detection method for furazolidone according to claim 1, characterized in that: In step (5) of the electrochemical detection of FZD, the pH of the PBS solution is 7.0.