An online synthesis method and apparatus for antibiotic adsorbent materials in aquaculture environments

Abstract

This invention discloses an online synthesis method and apparatus for antibiotic adsorbent materials in aquaculture environments, belonging to the field of environmental functional material synthesis and pollutant detection technology. This invention constructs a continuous-flow online synthesis platform by using a microfluidic chip as the core reactor and integrating precise temperature control and ultrasonic perturbation. The method provided by this invention enables on-demand preparation of adsorbent materials. The microfluidic chip achieves precise proportioning and instantaneous mixing of reactants, and the external temperature-controlled silicone tube reactor and ultrasonic assistance ensure efficient and uniform material synthesis within tens of minutes. The obtained material does not require drying and storage and can be directly used in subsequent extraction processes. Its surface functional groups exhibit high activity and good dispersibility, thus maximizing the excellent and consistent adsorption performance of each batch of material, laying a solid foundation for the accurate and reliable detection of trace antibiotics in aquaculture water.

Description

Technical Field

[0001] This invention belongs to the field of environmental functional material synthesis and pollutant detection technology, and particularly relates to an online synthesis method and apparatus for antibiotic adsorbent materials in aquaculture environments. Background Technology

[0002] The rapid development of aquaculture, while ensuring protein supply, has also led to severe aquatic pollution problems due to the widespread use of antibiotics. Although the concentrations of residual antibiotics such as sulfonamides, quinolones, and tetracyclines in aquaculture waters are low, their long-term presence poses a potential risk to the ecosystem and can be transmitted through the food chain, threatening human health. Accurate monitoring of these trace pollutants is a crucial step in implementing effective environmental regulation and risk assessment. Currently, high-sensitivity detection techniques such as high-performance liquid chromatography-mass spectrometry (HPLC-MS) have become the mainstream analytical method; however, the accuracy of the analytical results heavily relies on efficient and reliable pretreatment and enrichment methods. In this context, magnetic solid-phase extraction (MSE) technology is favored due to its ease of operation and rapid separation; the core of this technology lies in the development of high-performance magnetic adsorption materials.

[0003] Currently, widely used magnetic graphene oxide adsorbent materials mainly rely on traditional laboratory batch synthesis methods. These methods typically involve the high-temperature hydrothermal synthesis of NH₂-Fe₃O₄ magnetic spheres and the preparation of graphene oxide, a lengthy process often requiring tens of hours to complete. This time-consuming and labor-intensive synthesis model leads to several drawbacks that are severely disconnected from analytical testing needs: First, it is difficult to maintain optimal material performance. Materials synthesized using traditional methods require drying and storage before reconstitution, a process that easily leads to irreversible agglomeration of nanoparticles and a reduction in surface active sites, causing fluctuations in adsorption performance between different batches and directly affecting the accuracy and reproducibility of test data. Second, the synthesis process is severely disconnected from testing applications. The "synthesize-then-store-then-use" approach may fail to meet the urgent need for high-efficiency adsorption performance in on-site, rapid testing due to the decline in adsorption performance caused by long-term storage, making it difficult to achieve real-time linkage from sampling to analysis. Finally, traditional synthesis methods themselves suffer from high energy consumption, cumbersome steps, and the use of large amounts of hazardous chemicals, contradicting the development philosophy of green, safe, and efficient modern analytical laboratories.

[0004] Microfluidics, with its superior fluid manipulation capabilities in microscale spaces, has provided a new paradigm for the precise and continuous synthesis of nanomaterials. However, current technologies have not yet effectively addressed the challenges of reaction sufficiency and precise temperature control in the synthesis of composite materials such as magnetic graphene oxide within microchannels, thus limiting the application of synthesized materials in high-end analytical detection. Summary of the Invention

[0005] To address the technical bottlenecks of existing methods for synthesizing magnetic graphene oxide adsorbent materials, such as lengthy processes, high energy consumption, poor batch-to-batch stability of material performance, and inability to meet the on-the-spot preparation requirements in detection and analysis, this invention provides an online synthesis method and apparatus for antibiotic adsorbent materials in aquaculture environments. By constructing an integrated, continuous-flow synthesis system, the preparation process of high-performance magnetic adsorbent materials is revolutionized from the traditional batch reaction that takes tens of hours to an online, continuous process that can be completed within tens of minutes. This provides fresh materials with optimal adsorption performance for the pretreatment stage of antibiotic detection in environmental water samples, fundamentally solving the problems of poor reproducibility of detection results caused by agglomeration and activity decay of traditional dry-stored materials.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides an online synthesis method for antibiotic adsorbent materials in aquaculture environments, comprising the following steps:

[0008] (1) Fe3O4-NH2 nanoparticle solution, graphene oxide dispersion and activation solution are simultaneously injected into microfluidic chip through a three-channel injection pump for mixing to obtain a mixed solution; the flow channel of the microfluidic chip has a serpentine structure;

[0009] (2) The mixed solution is introduced into a long silicone tube and the long silicone tube is wound around a temperature control device. The reaction is carried out under heating and ultrasonic conditions to obtain the antibiotic adsorbent material in the aquaculture environment. The reaction temperature is 50°C and the time is 40 min.

[0010] Further, in step (1), the concentration of the Fe3O4-NH2 nanoparticle solution is 1-10 mg / mL; the concentration of the graphene oxide dispersion is 1-10 mg / mL;

[0011] The volume ratio of the Fe3O4-NH2 nanoparticle solution, the graphene oxide dispersion, and the activation solution is 1:1:1 to 1:2:1.

[0012] Further, in step (1), the activation solution is composed of MES buffer, carbodiimide (EDC) and N-hydroxysuccinimide (NHS); the pH value of the MES buffer in the activation solution is 5.6, the concentration of carbodiimide is 1-10 mg / mL, the concentration of N-hydroxysuccinimide is 0.5-5 mg / mL, and the molar ratio of carbodiimide to N-hydroxysuccinimide is 1:(0.5-2).

[0013] Furthermore, in step (1), the control mode of the three-channel injection pump is a multi-channel independent control mode, the flow rate of each channel is 0.1-1 mL / min, and the total feeding time is 30-60 min.

[0014] Further, in step (1), the cross-sectional dimensions of the microfluidic chip channel are 100-500μm×100-500μm, and the channel length is 5-20cm; the pressure resistance of the microfluidic chip is ≥10MPa;

[0015] The mixing is carried out under laminar flow conditions with a Reynolds number Re < 100.

[0016] Furthermore, in step (2), the inner diameter of the long silicone tube is 1.5 mm and the length is 2 m;

[0017] The long silicone tube is wound around the temperature control device in a spiral manner, with 50-80 turns.

[0018] Furthermore, in step (2), the temperature control device is a constant temperature water bath circulation system; the temperature control accuracy of the temperature control device is ±0.5℃, and the temperature control range is 25-60℃;

[0019] The ultrasonic power is 100-500W, the frequency is 20-40kHz, and the direction of the ultrasonic wave is perpendicular to the axis of the long silicone tube.

[0020] The present invention provides an online synthesis apparatus for the online synthesis method described in the above technical solution, characterized in that the online synthesis apparatus comprises: a three-channel injection pump system, a microfluidic chip module with a serpentine flow channel, a reaction pipeline system, a temperature control system, and an ultrasonic-assisted system.

[0021] Furthermore, the reaction pipeline system is composed of long silicone tubes; the temperature control system includes a heating roller, a temperature sensor, and a PID controller; and the ultrasonic auxiliary system includes an ultrasonic generator and a transducer array.

[0022] The present invention also provides an application of antibiotic adsorbent material obtained by the online synthesis method described above in the aquaculture environment for adsorbing and extracting antibiotics from aquaculture water.

[0023] Compared with the prior art, the present invention has the following advantages and technical effects:

[0024] This invention constructs a continuous-flow online synthesis platform by using a microfluidic chip as the core reactor and integrating precision temperature control and ultrasonic perturbation. The key advantage of this method lies in its ability to prepare adsorbent materials on-site. The microfluidic chip enables precise proportioning and instantaneous mixing of reactants, while an external temperature-controlled silicone tube reactor and ultrasonic assistance ensure efficient and uniform material synthesis within tens of minutes. The resulting material requires no drying or storage and can be directly used in subsequent extraction processes. Its high surface functional group activity and good dispersibility ensure excellent and consistent adsorption performance in each batch, laying a solid foundation for the accurate and reliable detection of trace antibiotics in aquaculture water. Compared to traditional methods, this invention not only achieves a leap in synthesis efficiency from hours to minutes but also seamlessly integrates material performance assurance with the actual needs of detection and analysis, providing a more advanced and reliable material preparation and supply model.

[0025] This invention revolutionizes the supply of magnetic adsorption materials by enabling on-the-spot preparation through online synthesis. This effectively prevents performance degradation caused by long-term storage and ensures high and consistent adsorption activity in each batch, significantly improving the accuracy and reproducibility of subsequent antibiotic detection data. Secondly, in terms of synthesis performance, this invention demonstrates superior efficiency, reducing synthesis time from several hours to 40 minutes compared to the traditional muffle furnace high-temperature hydrothermal synthesis method, and significantly increasing the yield to 99.2%. Furthermore, the entire synthesis process is conducted in a closed microfluidic pipeline with a mild reaction temperature, avoiding the use of high temperature, high pressure, and large amounts of hazardous chemicals, thus exhibiting better energy-saving, environmentally friendly, and safe characteristics. Microstructural characterization confirms that the materials synthesized using this method show no significant differences in morphology and structure compared to those synthesized using traditional methods. Moreover, in subsequent practical applications for the enrichment of various antibiotics such as sulfonamides, quinolones, and tetracyclines in aquaculture water samples, they demonstrated equally excellent or even better adsorption performance. This invention not only provides a reliable method for the immediate preparation of adsorbent materials for antibiotic residue detection, but also offers a novel technical path and apparatus template for the green and efficient synthesis of functional nanomaterials. Attached Figure Description

[0026] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0027] Figure 1 A schematic diagram of the online synthesis device provided by the present invention; wherein, 1-three-channel injection pump system, 2-microfluidic chip, 3-serpentine mixing channel, 4-temperature control system, 5-ultrasound-assisted system, 6-collection device, 7-long silicone tube;

[0028] Figure 2 The images show TEM images of the magnetic graphene oxide adsorbent materials obtained in Example 1 (heating temperature 50°C, time 40 min) and Comparative Example 1, where A represents Example 1 and B represents Comparative Example 1.

[0029] Figure 3 The graph shows a comparison of the adsorption efficiency of the magnetic graphene oxide adsorbent material obtained in Example 1 (heating temperature 50℃, time 40min) and Comparative Example 1 for seven quinolone antibiotics. The method described in Example 1 is the method described in Example 1, and the hydrothermal method is the method described in Comparative Example 1.

[0030] Figure 4 The cycling stability of the magnetic graphene oxide adsorbent material obtained in Example 1 when the heating temperature was 50°C and the time was 40 min. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] This invention provides an online synthesis method for antibiotic adsorbent materials in aquaculture environments, comprising the following steps:

[0034] (1) Fe3O4-NH2 nanoparticle solution, graphene oxide dispersion and activation solution are simultaneously injected into microfluidic chip through a three-channel injection pump for mixing to obtain a mixed solution; the flow channel of the microfluidic chip has a serpentine structure;

[0035] (2) The mixed solution is introduced into a long silicone tube and the long silicone tube is wound around a temperature control device. The reaction is carried out under heating and ultrasonic conditions to obtain the antibiotic adsorbent material in the aquaculture environment. The reaction temperature is 50°C and the time is 40 min.

[0036] In a preferred embodiment, in step (1), the concentration of the Fe3O4-NH2 nanoparticle solution is 1-10 mg / mL, more preferably 5 mg / mL; the concentration of the graphene oxide dispersion is 1-10 mg / mL, more preferably 5 mg / mL.

[0037] In a preferred embodiment, the solvent for the Fe3O4-NH2 nanoparticle solution is selected from water or MES buffer.

[0038] In a preferred embodiment, the preparation method of Fe3O4-NH2 nanoparticles in the Fe3O4-NH2 nanoparticle solution includes the following steps: dissolving FeCl3·6H2O in ethylene glycol to obtain a FeCl3·6H2O solution; adding anhydrous sodium acetate and 1,6-hexanediamine to the FeCl3·6H2O solution, stirring, and then transferring the resulting mixture to a high-pressure reactor and reacting at 198°C for 6 hours; after the reaction is completed, naturally cooling to room temperature, and washing and freeze-drying the reaction product to obtain Fe3O4-NH2 nanoparticles.

[0039] In a preferred embodiment, in the method for preparing Fe3O4-NH2 nanoparticles, the concentration of the FeCl3·6H2O solution is 0.05-0.2 mol / L; the molar ratio of FeCl3·6H2O, anhydrous sodium acetate, and 1,6-hexanediamine is 1:(2-5):(1-3).

[0040] In a preferred embodiment, in the method for preparing Fe3O4-NH2 nanoparticles, the stirring temperature is room temperature and the stirring time is 30 min.

[0041] In a preferred embodiment, in the preparation method of Fe3O4-NH2 nanoparticles, the reaction products are collected by a magnetic field; the washing is performed by alternating washing with ultrapure water and ethanol three times each; and the freeze-drying time is 24 hours.

[0042] In a preferred embodiment, the solvent for the graphene oxide dispersion is selected from water or MES buffer.

[0043] In a preferred embodiment, the method for preparing graphene oxide in the graphene oxide dispersion includes the following steps: adding graphite powder and NaNO3 to concentrated sulfuric acid, stirring under an ice bath, then slowly adding potassium permanganate to carry out an oxidation reaction, followed by adding distilled water to obtain a mixed solution; placing the mixed solution in a 98°C water bath and stirring, adding distilled water during the process, then adding 30% hydrogen peroxide to terminate the reaction, and obtaining graphene oxide by centrifugation, washing and drying.

[0044] In a preferred embodiment, during the preparation of graphene oxide, the ratio of graphite powder, NaNO3, concentrated sulfuric acid, and potassium permanganate by weight is 1:1:46:6.

[0045] In a preferred embodiment, during the preparation of graphene oxide, the stirring time under an ice bath is 10 min; the addition time of potassium permanganate is 10 min; the oxidation reaction time is 2 h, and the temperature is ≤10℃.

[0046] In a preferred embodiment, during the preparation of graphene oxide, the stirring time in a 98°C water bath is 15 min; the washing is performed by sequentially washing with 5% hydrochloric acid and pure water until neutral; and the drying method is vacuum drying for 12 h.

[0047] In a preferred embodiment, in step (1), the activation solution is a mixture of MES buffer, carbodiimide and N-hydroxysuccinimide; the pH of the MES buffer in the activation solution is 5.6, the concentration of carbodiimide is 1-10 mg / mL, the concentration of N-hydroxysuccinimide is 0.5-5 mg / mL, and the molar ratio of carbodiimide to N-hydroxysuccinimide is 1:(0.5-2).

[0048] In a preferred embodiment, in step (1), the volume ratio of the Fe3O4-NH2 nanoparticle solution, the graphene oxide dispersion, and the activation solution is 1:1:1-1:2:1.

[0049] In a preferred embodiment, in step (1), the control mode of the three-channel injection pump is a multi-channel independent control mode, the flow rate of each channel is 0.1-1 mL / min, and the total feeding time is 30-60 min.

[0050] In a preferred embodiment, in step (1), the flow channel of the microfluidic chip has a serpentine structure; the cross-sectional size of the flow channel of the microfluidic chip is 100-500μm×100-500μm, more preferably 200μm×200μm; the length of the flow channel of the microfluidic chip is 5-20cm, more preferably 10-15cm; and the pressure resistance of the microfluidic chip is ≥10MPa. This invention employs a microfluidic chip with an internally designed serpentine mixing flow channel, enabling the three solutions to achieve thorough and uniform mixing through diffusion and convection in a laminar flow state, laying the foundation for subsequent reactions.

[0051] In a preferred embodiment, in step (1), the mixing is carried out under laminar flow with a Reynolds number Re < 100.

[0052] In a preferred embodiment, in step (2), the inner diameter of the long silicone tube is 1.5 mm and its length is 2 m; the long silicone tube is wound spirally around the temperature control device, with 50-80 turns. The long silicone tube in this invention constitutes a continuous flow reactor, and the temperature of its internal reaction system is precisely controlled by the temperature control device to ensure uniform heating of the solution.

[0053] In a preferred embodiment, in step (2), the temperature control device is a constant temperature water bath circulation system; the temperature control accuracy of the temperature control device is ±0.5℃, and the temperature control range is 25-60℃.

[0054] In a preferred embodiment, the ultrasonic power is 100-500W, the frequency is 20-40kHz, and the direction of the ultrasonic wave is perpendicular to the axis of the long silicone tube.

[0055] The present invention provides an online synthesis apparatus for the online synthesis method described in the above technical solution, characterized in that the online synthesis apparatus comprises: a three-channel injection pump system, a microfluidic chip module with a serpentine flow channel, a reaction pipeline system, a temperature control system, and an ultrasonic-assisted system.

[0056] In a preferred embodiment, the microfluidic chip module with a serpentine flow channel is made of polymethyl methacrylate (PMMA); the serpentine flow channel is an irregular serpentine flow channel; the serpentine flow channel has a main flow channel that extends in a serpentine, meandering manner, and a secondary meandering path is provided within at least one straight section of the main flow channel. The secondary meandering path extends further within the straight section and is a zigzag path. This invention employs a microfluidic chip with an irregular serpentine flow channel, which helps to achieve thorough and uniform mixing of the three raw material liquids.

[0057] In a preferred embodiment, the reaction piping system is composed of a long silicone tube; the long silicone tube is wound spirally around the temperature control device.

[0058] In a preferred embodiment, the temperature control system includes a heating roller, a temperature sensor, and a PID controller; the heating roller has a diameter of 5-10 cm, and its surface is provided with equidistant spiral grooves for fixing a long silicone tube; the temperature control accuracy of the system is ±0.5℃. The temperature control system in this invention is used to ensure a constant reaction temperature.

[0059] In a preferred embodiment, the ultrasound-assisted system includes an ultrasound generator and a transducer array, the transducer array being uniformly distributed along the axial direction of a long silicone tube.

[0060] The online synthesis apparatus provided by this invention is a highly integrated system, mainly comprising: a microfluidic chip module as the core reactor, which has serpentine channels etched inside for efficient fluid mixing; a multi-channel injection pump system for precisely delivering Fe3O4-NH2 nanoparticle solution, graphene oxide dispersion, and activation solution; a tubular reactor composed of long silicone tubes; a precision temperature control system for winding the long silicone tubes and equipped with a PID control algorithm; and an ultrasonic-assisted system that provides uniform ultrasonic energy to the entire reaction system. The coordinated operation of these modules ensures the continuity, stability, and efficiency of the synthesis process.

[0061] A schematic diagram of the online synthesis device provided by this invention is shown below. Figure 1Its core includes a three-channel injection pump system 1 for precisely delivering Fe3O4-NH2 nanoparticle solution, graphene oxide dispersion and activation solution, and a microfluidic chip module 2 with a serpentine mixing channel connected to it. The outlet of the microfluidic chip module 2 is connected to a long silicone tube reaction pipeline system. The long silicone tube 7 is tightly wound on a temperature control system 4 precisely managed by a PID controller and is completely immersed in an ultrasonic-assisted system 5, thus forming a continuous flow synthesis system that integrates mixing, reaction, temperature control and ultrasonic assistance.

[0062] The present invention also provides an application of antibiotic adsorbent material obtained by the online synthesis method described above in the aquaculture environment for adsorbing and extracting antibiotics from aquaculture water.

[0063] In a preferred embodiment, the antibiotic is one or more of sulfonamide antibiotics, quinolone antibiotics, and tetracycline antibiotics.

[0064] In a preferred embodiment, the antibiotic adsorption efficiency of the antibiotic adsorbent material in the aquaculture environment is >99.2%; the antibiotic adsorbent material in the aquaculture environment can be reused ≥3 times.

[0065] In this embodiment of the invention, room temperature refers to "25±2℃".

[0066] Unless otherwise specified, all raw materials used in the embodiments of this invention were purchased through commercial channels.

[0067] In the following examples and comparative examples:

[0068] The preparation method of Fe3O4-NH2 nanoparticle solution is as follows: FeCl3·6H2O is dissolved in ethylene glycol under ultrasonic assistance to prepare a FeCl3·6H2O solution with a concentration of 0.1 mol / L; anhydrous sodium acetate and 1,6-hexanediamine are added to the obtained FeCl3·6H2O solution according to the molar ratio of FeCl3·6H2O, anhydrous sodium acetate and 1,6-hexanediamine of 1:3:2. After stirring at room temperature for 30 min, the mixture is transferred to a high-pressure reactor and reacted at 198℃ for 6 h; after the reaction is completed, the mixture is naturally cooled to room temperature, and the product is collected by applying an external magnetic field. The collected product is washed three times each with ultrapure water and ethanol, and finally freeze-dried for 24 h to obtain Fe3O4-NH2 nanoparticles; the obtained Fe3O4-NH2 nanoparticles are dispersed in water to prepare a Fe3O4-NH2 nanoparticle solution with a concentration of 5 mg / mL, which is used as solution A.

[0069] The preparation method of graphene oxide dispersion is as follows: 1 part by weight of graphite powder and 1 part by weight of NaNO3 are added to 46 parts by weight of concentrated sulfuric acid and stirred for 10 min under ice bath conditions. Then, 6 parts by weight of potassium permanganate are slowly added over 10 min, controlling the system temperature to not exceed 10℃. The solution gradually turns dark green. After continuous stirring for 2 h to complete the oxidation reaction, distilled water is slowly added to obtain a dark brown solution. The obtained dark brown solution is placed in a 98℃ water bath and stirred for 15 min, during which distilled water is added for dilution. Then, 30% hydrogen peroxide is added. The reaction is terminated after 1 h, and the solution gradually changes from yellow to brown. After centrifugation, it is washed successively with 5% hydrochloric acid and pure water until neutral, and vacuum dried for 12 h to obtain graphene oxide. The obtained graphene oxide is dispersed in water to prepare a graphene oxide dispersion with a concentration of 5 mg / mL, which is used as solution B.

[0070] Activation solution: It is a mixture of MES buffer, carbodiimide (EDC) and N-hydroxysuccinimide (NHS); the pH of the MES buffer is 5.6, the concentration of EDC is 10 mg / mL, the concentration of NHS is 2 mg / mL, and the molar ratio of EDC to NHS is 1:1, which is used as solution C.

[0071] Example 1

[0072] An online synthesis method for antibiotic adsorbent materials in aquaculture environments is described, and a schematic diagram of the online synthesis apparatus used is shown below. Figure 1 The online synthesis device consists of a three-channel injection pump system, a microfluidic chip module with a serpentine flow channel, a reaction tubing system, a temperature control system, and an ultrasonic-assisted system. The microfluidic chip module with the serpentine flow channel has a cross-sectional dimension of 200μm × 200μm, a channel length of 10cm, and is made of PMMA. The chip has a pressure resistance ≥10MPa and is also made of PMMA. The serpentine flow channel has a main flow channel that extends in a serpentine, meandering pattern. At least one straight section of the main flow channel contains a secondary meandering path. The secondary winding path extends further within the partition, forming a zigzag pattern. The reaction piping system consists of a 1.5mm inner diameter and 2m long silicone tube, which is spirally wound around the heating roller of the temperature control device. The temperature control system comprises the heating roller, a temperature sensor, and a PID controller. The heating roller has a diameter of 5cm and equidistant spiral grooves on its surface to fix the long silicone tube. The temperature control accuracy of the system is ±0.5℃. The ultrasonic auxiliary system consists of an ultrasonic generator and a transducer array, which is uniformly distributed along the axial direction of the long silicone tube.

[0073] The specific steps of the online synthesis method are as follows:

[0074] (1) Fe3O4-NH2 nanoparticle solution (solution A), graphene oxide dispersion (solution B) and activation solution (solution C) were simultaneously injected into a microfluidic chip module with a serpentine flow channel at a volume ratio of 1:1.5:1 using a three-channel injection pump system (the flow rate of the three solutions was 0.5 mL / min, and the total feeding time was 40 min). The mixture was then mixed under laminar flow conditions with a Reynolds number Re < 100 to obtain a mixed solution.

[0075] (2) The obtained mixed solution was introduced into a long silicone tube with an inner diameter of 1.5 mm and a length of 2 m, and the long silicone tube was wound in a spiral manner on the heating roller of the temperature control device, with 80 turns. Under the conditions of heating and ultrasound, magnetic graphene oxide adsorbent material was synthesized online, which is the antibiotic adsorbent material in the aquaculture environment. The ultrasound power was 200 W, the frequency was 40 kHz, and the ultrasound direction was perpendicular to the axis of the long silicone tube. The heating temperatures were 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, and 60℃, and the heating times were 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, and 80 min, respectively.

[0076] Comparative Example 1 (Traditional Synthesis Method)

[0077] A Fe3O4-NH2 nanoparticle solution with a concentration of 5 mg / mL, a graphene oxide dispersion with a concentration of 5 mg / mL, and an activation solution were mixed at a volume ratio of 1:1.5:1 and placed in a muffle furnace. The mixture was then heated at 190 °C for 6 h to obtain a magnetic graphene oxide adsorbent material.

[0078] Transmission electron microscopy (TEM) was used to observe the magnetic graphene oxide adsorbent material prepared in Example 1. The results showed that reaction temperature and reaction time were two key synergistic factors determining the loading effect of Fe3O4 nanoparticles on the graphene oxide sheets. At lower temperatures (e.g., 20-40℃) or shorter times (e.g., 10-30 min), TEM images showed that the loading density of Fe3O4 nanoparticles on the graphene oxide support was low and sparsely distributed, indicating that the amidation coupling reaction was insufficient. Conversely, at excessively high temperatures (e.g., 55-60℃) or excessively long times (e.g., exceeding 60 min), a significant tendency for Fe3O4 nanoparticles to agglomerate was observed, with sintering even occurring in some areas. This could potentially impair the effective specific surface area and dispersibility of the material. Comparing all combinations of conditions, the material synthesized under the conditions of a reaction temperature of 50℃ and a reaction time of 40 min exhibited the most ideal microstructure.

[0079] Figure 2The images show TEM images of the magnetic graphene oxide adsorbent materials obtained in Example 1 (heating temperature 50°C, time 40 min) and Comparative Example 1, where A represents Example 1 and B represents Comparative Example 1. Figure 2 As can be seen from Part A of the diagram, the Fe3O4 nanoparticles in the magnetic graphene oxide adsorbent material obtained in Example 1, heated to 50°C for 40 minutes, are uniform in size and well-dispersed. They are also anchored densely and uniformly on the surface of the graphene oxide sheets, forming a stable composite structure. Comparison with the sample prepared using the traditional muffle furnace high-temperature hydrothermal synthesis method (Comparative Example 1) reveals no significant difference in nanoparticle dispersion, loading density, or the integrity of the composite structure. This demonstrates the effectiveness of the online synthesis method of this invention in ensuring material structure quality, while also possessing the unparalleled advantages of speed and efficiency compared to traditional methods.

[0080] Adsorption experiment:

[0081] Seven quinolone antibiotics commonly used in aquaculture were selected as target analytes: ciprofloxacin, lomefloxacin, pefloxacin, enrofloxacin, norfloxacin, ofloxacin, and fleroxacin. A mixed antibiotic solution with a concentration of 0.2 mg / kg for each antibiotic was prepared to simulate polluted water. 1 mL of the above mixed antibiotic solution was thoroughly mixed with 1 mL of a suspension of magnetic graphene oxide adsorbent material obtained in Example 1 (heated at 50°C for 40 min) at a concentration of 20 mg / mL (i.e., the amount of adsorbent material added was 20 mg) or a suspension of magnetic graphene oxide adsorbent material obtained in Comparative Example 1. The mixture was vortexed to ensure complete contact, and then rapidly separated using an external magnetic field. The supernatant was collected and filtered, and then analyzed using high-performance liquid chromatography-mass spectrometry (HPLC-MS). The adsorption rate was calculated by comparing the peak areas of each antibiotic in the solution before and after adsorption. The results are shown in [Figure 1]. Figure 3 .

[0082] Figure 3 The graph shows a comparison of the adsorption efficiency of the magnetic graphene oxide adsorbent material obtained in Example 1 (heating temperature 50℃, time 40min) and Comparative Example 1 for seven quinolone antibiotics. The method described in Example 1 is the method described in Example 1, and the hydrothermal method is the method described in Comparative Example 1. Figure 3 The results show that the magnetic graphene oxide adsorbent material synthesized in this invention exhibits extremely high affinity and capture ability for all seven quinolone antibiotics mentioned above, with an adsorption rate of over 99% for each antibiotic. This superior adsorption performance verifies that the material synthesized online using the method and apparatus of this invention has abundant surface active sites and a complete structure, enabling it to efficiently enrich trace amounts of various antibiotic residues in water, fully meeting the stringent requirements for adsorbent materials in high-sensitivity detection pretreatment processes.

[0083] Seven quinolone antibiotics commonly used in aquaculture were selected as target analytes: ciprofloxacin, lomefloxacin, pefloxacin, enrofloxacin, norfloxacin, ofloxacin, and fleroxacin. A mixed antibiotic solution with a concentration of 0.2 mg / kg for each antibiotic was prepared to simulate polluted water. 1 mL of the mixed antibiotic solution was mixed thoroughly with 1 mL of a suspension of magnetic graphene oxide adsorbent material (obtained in Example 1 at 50°C for 40 min with a concentration of 20 mg / mL) (i.e., the amount of adsorbent material added was 20 mg). The mixture was vortexed to ensure complete contact, followed by rapid separation using an external magnetic field. The supernatant was collected and filtered. The filtered solid was reused in the adsorption experiment for seven consecutive times. The capture efficiency of the adsorbent material for the antibiotics was recorded after each adsorption experiment. The results are shown in [Figure number missing]. Figure 4 .

[0084] Figure 4 The cycling stability of the magnetic graphene oxide adsorbent material obtained in Example 1 when heated to 50°C for 40 minutes is measured. Figure 4 It can be seen that the magnetic graphene oxide adsorbent material obtained in Example 1, with a heating temperature of 50℃ and a time of 40 min, did not show a significant decrease in antibiotic capture efficiency after being cycled 3 times, indicating that the magnetic graphene oxide adsorbent material prepared in this invention has good cycle stability.

[0085] The above embodiments fully demonstrate that the online synthesis method and apparatus provided by the present invention can not only significantly shorten the synthesis time and reduce energy consumption, but also ensure that the prepared magnetic adsorption material has a stable and excellent microstructure and excellent adsorption performance, providing a reliable material basis and technical support for the rapid and accurate detection of antibiotics in environmental water bodies.

[0086] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for the in-line synthesis of an antibiotic adsorbent material in an aquaculture environment, characterized in that, The method comprises the following steps: (1) Fe3O4-NH2 nanoparticle solution, graphene oxide dispersion and activation solution are synchronously injected into a microfluidic chip through a three-channel injection pump for mixing to obtain a mixed solution; the flow channel of the microfluidic chip is a serpentine structure; the activation solution is mixed from MES buffer, carbodiimide and N-hydroxysuccinimide; (2) The mixed solution is introduced into a long silica gel tube, and the long silica gel tube is wound on a temperature control device to react under the conditions of heating and ultrasonic to obtain the antibiotic adsorption material in the aquatic environment; the reaction temperature is 50 DEG C, and the reaction time is 40 min.

2. The method for on-line synthesis of an antibiotic adsorbent material in an aquaculture environment according to claim 1, characterized in that, In step (1), the concentration of the Fe3O4-NH2 nanoparticle solution is 1-10 mg / mL; the concentration of the graphene oxide dispersion is 1-10 mg / mL; The volume ratio of the Fe3O4-NH2 nanoparticle solution, the graphene oxide dispersion and the activation solution is 1:1:1-1:2:

1.

3. The method for in-line synthesis of an antibiotic adsorbent material in an aquaculture environment according to claim 1, wherein, In step (1), the pH value of the MES buffer in the activation solution is 5.6, the concentration of the carbodiimide is 1-10 mg / mL, the concentration of the N-hydroxysuccinimide is 0.5-5 mg / mL, and the molar ratio of the carbodiimide to the N-hydroxysuccinimide is 1: (0.5-2).

4. The method for in-line synthesis of an antibiotic adsorbent material in an aquaculture environment according to claim 1, wherein, In step (1), the control mode of the three-channel injection pump is a multi-channel independent control mode, the flow rate of each channel is 0.1-1 mL / min, and the total feeding time is 30-60 min.

5. The method of online synthesis of an antibiotic adsorbent material in an aquaculture environment according to claim 1, wherein, In step (1), the cross-sectional dimension of the flow channel of the microfluidic chip is 100-500 μm x 100-500 μm, and the length of the flow channel is 5-20 cm; the pressure resistance of the microfluidic chip is ≥10 MPa; and / or, The mixing is carried out under laminar flow with Reynolds number Re < 100.

6. The method for in-line synthesis of an antibiotic adsorbent material in an aquaculture environment according to claim 1, wherein, In step (2), the inner diameter of the long silica gel tube is 1.5 mm, and the length is 2 m; The long silica gel tube is wound on the temperature control device in a spiral manner, and the number of winding turns is 50-80 turns.

7. The method for in-line synthesis of an antibiotic adsorbent material in an aquaculture environment according to claim 1, wherein, In step (2), the temperature control device is a constant temperature water bath circulation system; and / or, The power of the ultrasonic is 100-500 W, the frequency is 20-40 kHz, and the direction of the ultrasonic is perpendicular to the axial direction of the long silica gel tube.

8. The use of the antibiotic adsorption material in the aquatic environment obtained by the online synthesis method of any one of claims 1-7 for adsorbing antibiotics in the extraction of aquaculture water.

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