Passive sampling device and method for specifically enriching quinolone and tetracycline antibiotics

Abstract

The invention discloses a passive sampling device and method for specifically enriching quinolones and tetracyclines antibiotics, and relates to water body detection. Firstly, a hydrogel thin film prepared from ZIF-C as an adsorbent is adopted as a binding film, ZIF-C particles are uniformly dispersed on the surface of the binding film, specific adsorption of quinolones and tetracyclines antibiotics can be achieved, then the binding film, a diffusion film and a polyether sulfone filtering film are sequentially stacked to be assembled into an o-DGT device, o-DGT is put into a water body, and through diffusion and adsorption, the specific adsorption of the quinolones and tetracyclines antibiotics can be achieved. The method realizes the extraction and detection of quinolone and tetracycline antibiotics by the DGT technology.

Description

Technical Field

[0001] This invention relates to a specific in-situ sampling device for quinolone and tetracycline antibiotics in water, which can be used for simultaneous in-situ detection and contamination risk assessment of quinolone and tetracycline antibiotics in water. Background Technology

[0002] Antibiotics are a class of antimicrobial chemicals that kill or inhibit bacterial growth, playing a crucial role in treating and preventing bacterial infections in humans and animals. However, they also exhibit significant adverse effects on human health and ecological stability. Studies have found that 30%–90% of antibiotics cannot be completely absorbed and metabolized by the host organism, with the majority ultimately entering the aquatic environment through wastewater or excrement as parent compounds or metabolites. Therefore, a thorough and systematic explanation of the migration and distribution patterns of antibiotic pollutants in water, soil, and sediments is needed, along with elucidating their fate mechanisms, accurately assessing their ecological risk levels, and formulating effective emission control targets to genuinely protect the environment and human health.

[0003] Metal-organic frameworks (MOFs), a novel type of porous material formed by the self-assembly of metal ions or metal clusters with organic ligands through coordination interactions, have attracted widespread attention and importance. The unique morphology, regular and uniform pores, abundant coordination unsaturated centers, and surface functionalizability of MOFs distinguish them from other traditional porous materials, making them excellent adsorbents for removing various pollutants from the environment, including gaseous pollutants, heavy metal pollutants, and dyes.

[0004] Organic-diffusive gradients in thin-films (DGT) is a kinetic passive sampler invented by Davlson W. and Zhang H in 1994. Developed from Fick's first law, it can efficiently and accurately enrich and quantify substances, eliminating the influence of external factors on unstable pollutant concentrations. Initially applied to the determination of metal ions, DGT was later applied to the monitoring of nutrients and trace organic pollutants, and was named o-DGT. Based on the difference in chemical potential between the environmental medium and the o-DGT, pollutants spontaneously migrate into the o-DGT device, diffuse sequentially through the filter layer and diffusion layer, and are rapidly and irreversibly adsorbed by the binding layer. Compared with other passive samplers, the sampling rate of o-DGT is independent of flow rate; therefore, the concentration of the environmental medium can be directly deduced from the measured diffusion coefficient, enabling in-situ detection of pollutants.

[0005] Based on the installation time of the device in the environment and the window area of ​​the DGT device, the flux of the target substance moving into the DGT, i.e., the measured pollutant concentration C, can be obtained by measuring the cumulative mass of the target substance inside the DGT. DGT， The calculation formula is as follows:

[0006] (1)

[0007] Where: D is the diffusion coefficient of the antibiotic in the diffusion layer (cm²). 2 · s -1 Δg is the thickness of the DGT diffusion layer (cm), which is determined during the DGT fabrication process; M is the cumulative mass of antibiotics in the adsorption or binding membrane (ng); T is the device placement time (s); and A is the window area of ​​the DGT (cm²). 2 ).

[0008] In this invention, the DGT diffusion layer thickness is 0.05 cm, the adsorption film thickness is 0.08 cm, and the window area is 3.14 cm². 2 .

[0009] A search revealed a method for preparing a dual-emission fluorescence sensor, its product, and its application disclosed on November 26, 2024 (patent application number: CN202411701135.0). The dual-emission fluorescence sensor prepared by this method has the advantages of high sensitivity and fast detection speed for four tetracycline antibiotics: doxycycline, tetracycline, oxytetracycline, and aureocycline. However, this device cannot simultaneously detect quinolone antibiotics in the environment.

[0010] A search revealed a metal polyphenol network-supported ZIF-8 composite material, its preparation method, and its application, disclosed on July 2, 2024 (Patent Application No.: CN202410563073.5). This invention discloses a metal polyphenol network-supported ZIF-8 composite material, its preparation method, and its application. A composite adsorbent is prepared by covalently coating a metal polyphenol network onto its surface. Based on the synergistic effects of π-π interactions, electrostatic interactions, and hydrogen bonding, it is used for the adsorption of fluoroquinolone antibiotics. However, this material cannot simultaneously adsorb and detect tetracyclic antibiotics in the environment, which has certain limitations. Summary of the Invention

[0011] 1. Key technical problem to be solved by the invention

[0012] When using o-DGT technology to study antibiotics in the environment, the commonly used binding layer is a broad-spectrum resin material. Coexisting substances in the natural environment may compete with the target antibiotic for adsorption, limiting its adsorption capacity and restricting its deployment in practical environments. This invention discloses a method for specifically enriching quinolone antibiotics (such as ofloxacin, enrofloxacin, ciprofloxacin, norfloxacin, etc.) and tetracycline antibiotics (such as tetracycline, chlortetracycline, oxytetracycline, etc.) in water. It uses ZIF-C, a material with high specificity for quinolone and tetracycline antibiotics, as the binding membrane material, achieving in-situ sampling by extracting these two antibiotics from the environment. This DGT detection is accurate, providing the time-averaged concentration of quinolone and tetracycline antibiotics in the environmental medium, compensating for the large errors caused by the discontinuity of instantaneous active sampling methods. Furthermore, DGT technology utilizes the mass exchange between the environmental medium and the DGT device to achieve diffusion equilibrium for sampling, thereby obtaining the bioeffective concentration of quinolone and tetracycline antibiotics at the detection location. This method solves the problems of traditional quinolone and tetracycline antibiotic detection methods, such as long processing time, complex pretreatment, high cost, and the inability to detect only total antibiotic concentration.

[0013] 2. Technical Solution

[0014] In a first aspect, the present invention provides a method for preparing a binding membrane that specifically adsorbs quinolone and tetracycline antibiotics, comprising the following steps:

[0015] (1) Add 2-methylimidazolium organic ligand solution to the metal salt organic solution, stir at room temperature for 24 h, wash and dry the solid particles with organic solvent to obtain Zn / Co-ZIF for later use.

[0016] (2) The Zn / Co-ZIF obtained in step (1) is carbonized under high temperature conditions to obtain metal carbon material (ZIF-C) consisting of metal oxide and carbon nanotubes.

[0017] (3) Add the above ZIF-C and agarose granules to deionized water one after another, and melt them into a gel by microwave heating. Pour the gel into the gap between two glass plates with a U-shaped plastic sheet sandwiched in between, place the glass plates horizontally at room temperature to cool for 1-2 hours, and slice them after solidification.

[0018] The metal salt organic solution mentioned in step (1) of this invention is a methanol solution with a molar ratio of Zn(NO3)2 and Co(NO3)2 of 1:3, and the organic solvent is methanol;

[0019] The high-temperature carbonization described in step (2) of this invention is carbonization under nitrogen conditions; the high temperature is 900℃, the heating rate is 10℃ / min, and the holding time is 5h.

[0020] In step (3) of the present invention, the concentrations of ZIF-C and agarose in the obtained gelatinous liquid are 2.0~3.0 g / L and 15~20 g / L, respectively.

[0021] A second aspect of the present invention provides a method for in-situ detection of quinolone and tetracycline antibiotics in the environment, comprising the following steps:

[0022] (1) Preparation of the binding membrane: ZIF-C and agarose particles were added to deionized water and melted into a gel by microwave heating. The gel was then injected into the gap between two glass plates with a U-shaped plastic sheet sandwiched between them. The glass plates were placed horizontally at room temperature and cooled for 1-2 hours. After solidification, the glass plates were sliced.

[0023] (2) Preparation of diffusion membrane: Agarose and deionized water are mixed in proportion and microwaved until they become a transparent gel-like liquid. The mixture is then injected into the gap between two glass plates with a U-shaped plastic sheet sandwiched between them. The glass plates are placed horizontally at room temperature and cooled for 1-2 hours. After solidification, the mixture is sliced.

[0024] (3) o-DGT device assembly: The binding membrane, diffusion membrane and polyethersulfone filter membrane are stacked in sequence and then assembled into an o-DGT device;

[0025] (4) Placement of o-DGT device: Place the o-DGT device in the water body to be tested for adsorption of quinolone and tetracycline antibiotics for a duration of T; o-DGT device recovery: After removing the o-DGT device, rinse it with deionized water to remove the binding membrane;

[0026] (5) Antibiotic extraction: The conjugate membrane was placed in methanol-formic acid (vmethanol:vformic acid=9:1) elution solution, sonicated for 30 min, and then the conjugate membrane was removed.

[0027] (6) Antibiotic determination: After the eluent obtained in step (5) was blown to near dryness using a nitrogen blower, it was reconstituted with deionized water, and the content of the corresponding antibiotic M in the extract was determined by high performance liquid chromatography-mass spectrometry.

[0028] In further steps (4)-(6), based on the setup time of the device in the environment and the window area of ​​the DGT device, the flux of the target substance inside the DGT, i.e., the measured pollutant concentration C, can be obtained by measuring the cumulative mass of the target substance inside the DGT. DGT， The calculation formula is as follows:

[0029] (1)

[0030] Where: D is the diffusion coefficient of the antibiotic in the diffusion layer (cm²). 2 · s -1The values ​​can be measured experimentally or obtained from data. Δg is the thickness of the DGT diffusion layer (cm), which is determined during the DGT fabrication process; M is the cumulative mass of antibiotic in the binding membrane (ng); T is the device placement time (s); and A is the window area of ​​the DGT (cm²). 2 ).

[0031] In this invention, the DGT diffusion layer thickness is 0.05 cm, the adsorption film thickness is 0.08 cm, and the window area is 3.14 cm². 2 .

[0032] The above-mentioned duration T should be less than or equal to the time when the adsorption amount is proportional to the duration, such as less than 200 hours; the water body for in-situ measurement includes those that are static or constantly flowing.

[0033] It can detect the concentrations of two different classes of antibiotics, quinolones and tetracyclines, in water at the same time.

[0034] 3. Beneficial effects

[0035] (1) This invention provides a method for preparing a metal-carbon bound membrane based on MOF derivatives. A metal-carbon bound membrane is prepared by using high-temperature carbonized Zn / Co-ZIF as an adsorbent and forming a film with agarose gel. ZIF-C particles are uniformly dispersed on the surface of the bound membrane, enabling specific adsorption of quinolone and tetracycline antibiotics. The bound membrane of this invention has a large adsorption capacity and is less affected by environmental factors such as ionic strength and pH, exhibiting good stability in practical applications.

[0036] (2) This invention provides a method for the specific in-situ detection of quinolone and tetracycline antibiotics in water based on DGT technology. A DGT device is assembled by selecting a ZIF-C binding membrane with high specificity and high adsorption capacity, a diffusion membrane made of agarose gel, and a polyethersulfone filter membrane. The device can be directly placed in the environmental medium, and the extraction and detection of quinolone and tetracycline antibiotics can be achieved by DGT technology through diffusion and adsorption.

[0037] (3) In this invention, the in-situ extraction of DGT is less affected by environmental conditions such as pH and ionic strength. The high capacity of the adsorption membrane enables the detection of antibiotics in the environment, ensuring the accuracy of the detection results.

[0038] (4) In the DGT device of the present invention, not only are the raw materials such as agarose and diffusion layer inexpensive and readily available, but the preparation process is also simple. Compared with conventional sampling techniques, DGT technology is simple and labor-saving to operate, convenient to analyze, and the test results are representative over a time span. It can be used for in-situ detection of quinolone and tetracycline antibiotics in water and for environmental risk assessment. Attached Figure Description

[0039] Figure 1 Selective adsorption of ofloxacin and tetracycline by the adsorption membrane

[0040] Figure 2 Adsorption capacity of the binding membrane for quinolone and tetracycline antibiotics

[0041] Figure 3 Elution efficiency of binding membranes for quinolone and tetracycline antibiotics

[0042] Figure 4 DGT collected antibiotic quality at different times

[0043] Figure 5 Effect of ion strength on the sampling performance of DGT device

[0044] Figure 6 The effect of pH on the sampling performance of DGT devices

[0045] Figure 7 Concentrations of quinolone and tetracycline antibiotics in wastewater treatment plant inlet and outlet water were measured using both DGT (Digital Tapping Therapy) devices and active sampling methods. Detailed Implementation

[0046] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0047] Preparation of adsorption membrane:

[0048] (1) Add 2-methylimidazolium organic ligand solution to the metal salt organic solution, stir at room temperature for 24 h, wash and dry the solid particles with organic solvent to obtain Zn / Co-ZIF for later use.

[0049] (2) The Zn / Co-ZIF obtained in step (1) is carbonized under high temperature conditions to obtain a metal carbon material (ZIF-C) composed of metal oxide and carbon nanotubes.

[0050] (3) Add the above ZIF-C and agarose granules to deionized water one after another, melt them into a gel by microwave heating, inject them into the gap between two glass plates with U-shaped plastic sheets, place the glass plates horizontally at room temperature to cool for 1-2 hours, and slice them after solidification.

[0051] The metal salt organic solution mentioned in step (1) is a methanol solution with a molar ratio of Zn(NO3)2 and Co(NO3)2 of 1:3, and the organic solvent is methanol;

[0052] The high-temperature carbonization described in step (2) is carbonization under nitrogen conditions; the high temperature is 900℃, the heating rate is 10℃ / min, and the holding time is 5h.

[0053] In step (3), the concentrations of ZIF-C and agarose in the resulting gel-like liquid are 2.5 g / L and 15 g / L, respectively.

[0054] Example 1

[0055] This embodiment examines the specific adsorption performance of the adsorption membrane for quinolone and tetracycline antibiotics.

[0056] A mixed solution containing 2 mg / L ofloxacin, tetracycline, sulfamethoxazole, and erythromycin was prepared in a 10 mL brown glass bottle. Before placing the adsorption membrane, the concentration of each antibiotic in the original solution was measured. Then, the adsorption membrane was placed in the bottle and shaken at room temperature for 12 h. After that, the solution was removed and the concentration of each antibiotic in the remaining solution was measured. The mass of antibiotics adsorbed by the adsorption membrane was calculated by calculating the concentration difference between the two solutions, and the adsorption capacity of the adsorption membrane for each substance was determined.

[0057] like Figure 1 As shown, the adsorption mass of ofloxacin and tetracycline is significantly higher than that of sulfamethoxazole and erythromycin, indicating that the adsorption membrane exhibits good adsorption capacity for ofloxacin and tetracycline, while its adsorption capacity for sulfamethoxazole and erythromycin is poor, proving that the membrane has good specificity for quinolone antibiotics and tetracycline antibiotics.

[0058] Example 2

[0059] This embodiment examines the adsorption and elution performance of the adsorption membrane.

[0060] Prepare an antibiotic solution with a concentration of 50 mg / L in a 10 mL brown glass bottle. Before placing the adsorption membrane, measure the concentration of each antibiotic in the original solution. Then, place the adsorption membrane into the solution, shake it at room temperature for 12 h, and remove it. Measure the concentration of each antibiotic in the remaining solution and calculate the difference between the two antibiotic concentrations to obtain the amount of antibiotic adsorbed by the adsorption layer.

[0061] Depend on Figure 2 The maximum adsorption capacities of the adsorption membrane for quinolone antibiotics (ofloxacin, enrofloxacin, ciprofloxacin, norfloxacin) and tetracycline antibiotics (tetracycline, chlortetracycline, oxytetracycline) were 58.9–132.1 μg / tablet and 92.8–110.2 μg / tablet, respectively. The thickness of the adsorption membrane was 0.08 cm, and the surface area was 3.14 cm². 2 .

[0062] A 2 mg / L antibiotic solution was placed in a 10 mL amber glass bottle. Before placing the adsorption membrane, the concentration of each antibiotic in the original solution was measured. The adsorption membrane was then placed in the bottle and shaken at room temperature for 12 h. The remaining solution was then used to measure the concentration of each antibiotic. The removed adsorption membrane was placed in 10 mL of formic acid-methanol solution (v:v:formic acid = 1:1) as eluent and sonicated for 30 min. The membrane was then removed. The eluent was concentrated to near dryness using a nitrogen blower and then reconstituted with deionized water. The antibiotic concentration in the reconstituted solution was determined using high-performance liquid chromatography-mass spectrometry (HPLC-MS). The difference between the obtained antibiotic concentration and the concentration in the original solution was used to calculate the elution efficiency.

[0063] like Figure 3 As shown, the elution efficiency of this adsorption membrane for quinolone antibiotics is approximately 67%–99%, and for tetracycline antibiotics, it is approximately 34%–39%. In practical applications, the elution efficiency is multiplied by the concentration measured by the device to obtain the actual concentration of the substance in the environment.

[0064] Example 3

[0065] This embodiment examines the sampling dynamics of the DGT device.

[0066] An antibiotic solution with a concentration of 200 μg / L was prepared in a 5 L beaker. Before placing the specific DGT device, the concentration of each antibiotic in the stock solution was measured. The solution was then placed in the device and stirred at 300 rpm at room temperature. The solution was removed after 12, 24, 48, 72, and 144 h. The adsorption membrane in the device was removed and eluted. The antibiotic concentration in the reconstituted solution was determined using high-performance liquid chromatography-mass spectrometry (HPLC-MS), and the antibiotic concentration was calculated according to the DGT concentration formula. Figure 4 As shown, DGT exhibited linear extraction of all seven antibiotics over time, meeting the application conditions for DGT dynamic sampling, and preliminarily proving that this DGT is suitable for the collection of quinolone and tetracycline antibiotics in water.

[0067] Example 4

[0068] This embodiment examines the effectiveness of the DGT device under different ionic strengths.

[0069] Solutions containing 0.001 M, 0.01 M, and 0.05 M NaCl, with an antibiotic concentration of 100 μg / L, were prepared in 1 L beakers. Before placing the specific DGT device, the concentration of each antibiotic in the stock solution was measured. The solutions were then placed in the device and stirred at 300 rpm for 24 h at room temperature. The adsorption membrane in the device was removed, and eluted using the eluent from Example 2. The antibiotics in the eluent were determined using high-performance liquid chromatography-mass spectrometry (HPLC-MS), and the antibiotic concentrations were calculated. DGT To measure antibiotic concentration, C SOLNThe ratio of the two values ​​represents the concentration of antibiotics in the original solution. The closer the ratio is to 1, the more accurate the results of the device's determination of the target analyte under these conditions.

[0070] like Figure 5 As shown, C DGT / C SOLN The values ​​remained between 0.8 and 1.2 under the three ionic strength conditions, indicating that the device maintained good effectiveness even at higher ionic strengths.

[0071] Example 5

[0072] This embodiment examines the effectiveness of the DGT device at different pH levels.

[0073] Antibiotic solutions with a pH of 4-9 and a concentration of 2 mg / L were prepared in 1 L beakers. Before placing the specific DGT device, the concentration of each antibiotic in the stock solution was measured. Then, the solutions were placed in the device and stirred at 300 rpm for 24 h at room temperature. The adsorption membrane in the device was removed, and eluted with the eluent from Example 2. The antibiotics in the eluent were determined by high performance liquid chromatography-mass spectrometry (HPLC-MS), and the antibiotic concentrations were calculated.

[0074] like Figure 6 As shown, C DGT / C SOLN The values ​​remained between 0.8 and 1.2 under pH conditions of 4-9, indicating that the device maintained good adsorption performance over a wide pH range.

[0075] Example 6

[0076] DGT Practical Applications

[0077] The DGT prepared according to this invention was applied to the determination of antibiotics in actual water bodies. The DGT device was immersed at the inlet of a wastewater treatment plant for 7 days. The adsorption membrane was then removed, and an elution experiment was performed on the adsorption membrane using the eluent from Example 2. The eluent was nitrogen-blown to near dryness, then reconstituted with distilled water. Finally, the reconstituted solution was quantitatively analyzed using LC-MS / MS. Active sampling was simultaneously performed at the inlet for control.

[0078] like Figure 7 As shown, in a wastewater treatment plant, four quinolone antibiotics (ofloxacin, norfloxacin, enrofloxacin, and ciprofloxacin) and two tetracycline antibiotics (tetracycline and oxytetracycline) were detected in the inlet using both passive and active sampling methods (DGT). Figure 7The results showed that passive and active sampling methods had consistent detection capabilities for target antibiotics. Furthermore, the passive sampling method (DGT) performed well for most antibiotics. Active sampling, however, is more susceptible to factors such as rainfall and emissions in practical applications. Therefore, this passive sampling device can be applied in real-world environmental monitoring, providing a more accurate description of the time-averaged and bioavailable concentrations of antibiotics.

[0079] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a binding membrane that specifically enriches quinolone and tetracycline antibiotics, characterized in that, Includes the following steps: (1) Add 2-methylimidazolium organic ligand solution to metal salt organic solution, stir at room temperature for 24 h, wash and dry solid particles with organic solvent to obtain Zn / Co-ZIF for later use; (2) The Zn / Co-ZIF obtained in step (1) is carbonized under high temperature conditions to obtain metal carbon material (ZIF-C) of metal oxide and carbon nanotubes. (3) Add the above ZIF-C and agarose granules to deionized water one after another, and melt them into a gel by microwave heating. Pour the gel into the gap between two glass plates with a U-shaped plastic sheet sandwiched in between, place the glass plates horizontally at room temperature to cool for 1-2 hours, and slice them after solidification.

2. The method according to claim 1, characterized in that, The metal salt organic solution mentioned in step (1) is a methanol solution with a molar ratio of Zn(NO3)2 and Co(NO3)2 of 1:3, and the organic solvent is methanol.

3. The method according to claim 1, characterized in that, The high-temperature carbonization described in step (2) is carbonization under nitrogen conditions; the high temperature is 900℃, the heating rate is 10℃ / min, and the holding time is 5h.

4. The method according to claim 1, characterized in that, In step (3), the concentrations of ZIF-C and agarose in the resulting gel-like liquid are 2.0~3.0 g / L and 15~20 g / L, respectively.

5. A binding membrane specifically enriched with quinolone and tetracycline antibiotics prepared according to the method of any one of claims 1-4.

6. A passive sampling device for specifically enriching quinolone and tetracycline antibiotics, characterized in that, The binding membrane that specifically adsorbs quinolone and tetracycline antibiotics is used as the binding membrane of the gradient diffusion thin film passive sampler (DGT); the binding membrane that specifically adsorbs quinolone and tetracycline antibiotics is the binding membrane that specifically enriches quinolone and tetracycline antibiotics prepared according to the method of any one of claims 1-4.

7. The application of the passive sampling device according to claim 6, for in-situ detection of the concentration of quinolone and tetracycline antibiotics in the environment.

8. A method for in-situ detection of quinolone and tetracycline antibiotics in the environment, characterized in that, Includes the following steps: (1) Preparation of the binding membrane: prepared according to the method of any one of claims 1-4; (2) Preparation of diffusion membrane: Mix agarose and deionized water in a certain proportion and microwave heat until it becomes a transparent gel-like liquid. Inject it into the gap between two glass plates with a U-shaped plastic sheet sandwiched in between. Place the glass plates horizontally at room temperature and cool for 1-2 hours. After solidification, slice it. (3) o-DGT device assembly: The binding membrane, diffusion membrane and polyethersulfone filter membrane are stacked in sequence and then assembled into an o-DGT device; (4) Placement of o-DGT device: Place the o-DGT device in the water body to be tested for adsorption of quinolone and tetracycline antibiotics for a duration of T; o-DGT device recovery: After removing the o-DGT device, rinse it with deionized water to remove the binding membrane; (5) Antibiotic extraction: The conjugate membrane was placed in methanol-formic acid (vmethanol:vformic acid=9:1) elution solution, sonicated for 30 min, and then the conjugate membrane was removed. (6) Antibiotic determination: After the eluent obtained in step (5) was blown to near dryness using a nitrogen blower, it was reconstituted with deionized water, and the content of the corresponding antibiotic M in the extract was determined by high performance liquid chromatography-mass spectrometry. In steps (4) to (6), based on the setup time of the device in the environment and the window area of ​​the DGT device, the flux of the target substance inside the DGT, i.e., the measured pollutant concentration C, can be obtained by measuring the cumulative mass of the target substance inside the DGT. DGT， The calculation formula is as follows: （1） Where: D is the diffusion coefficient of the antibiotic in the diffusion layer (cm²). 2 · s -1 The values ​​can be measured experimentally or obtained from data. Δg is the thickness of the DGT diffusion layer (cm), which is determined during the DGT fabrication process; M is the cumulative mass of antibiotic in the binding membrane (ng); T is the device placement time (s); and A is the window area of ​​the DGT (cm²). 2 ); The preferred DGT diffusion layer thickness is 0.05 cm, the adsorption film thickness is 0.08 cm, and the window area is 3.14 cm². 2 .

9. The method according to claim 8, characterized in that, The above-mentioned time T should be less than or equal to the time when the adsorption amount is proportional to the time; the water body measured in situ includes water that is stationary or constantly flowing.

10. The method according to claim 8, characterized in that, It can detect the concentrations of two different classes of antibiotics, quinolones and tetracyclines, in water at the same time.

Images