A molecularly imprinted fluorescent sensor for detecting tetracycline antibiotics and a preparation method thereof
Patent Information
- Application Number
- CN202311666901.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-06
- Publication Date
- 2026-10-30
- Estimated Expiration
- 2043-12-06
AI Technical Summary
但是，目前检测四环素类抗生素的方法主要依赖于实验室的各种大型仪器，如：液相色谱仪、液相色谱质谱联用仪和薄层色谱仪等，导致检测费用高昂，且费时费力，难以实现实时的现场检测
[0019]本发明制备的荧光传感器表面的分子印迹空穴能够吸附四环素，并以氢键等弱的化学作用力相结合，四环素吸收了荧光传感器的部分激发光能量，减弱了荧光传感器的荧光，且随着四环素浓度增大，吸收激发光能量增加，最终导致荧光传感器荧光猝灭，因此，本发明制备的荧光传感器对四环素类抗生素能够特异性识别，具有抗干扰能力强，能够以高灵敏度在短时间内检测畜禽肉及环境水样中四环素类抗生素的优点，能够反复多次使用，节省了检测成本，提高了检测效率，实现了对四环素类抗生素的现场实时检测。
Smart Images
Figure CN117659252B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of antibiotic detection technology, specifically a molecularly imprinted fluorescent sensor for detecting tetracycline antibiotics and its preparation method. Background Technology
[0002] Tetracycline antibiotics, a class of broad-spectrum antibiotics produced by actinomycetes, were discovered in the late 1940s. They are primarily used to treat infectious diseases caused by Gram-positive and Gram-negative bacteria, intracellular mycoplasma, chlamydia, and rickettsiae, and possess anti-inflammatory, anti-apoptotic, and neuroprotective effects. In recent years, these antibiotics have been widely used in livestock farming and clinical practice. However, excessive and prolonged use of antibiotics can lead to decreased immunity and even other diseases. Therefore, the detection of tetracycline antibiotics in livestock and poultry meat products, water bodies, and food is particularly important. However, current methods for detecting tetracycline antibiotics mainly rely on various large-scale laboratory instruments, such as liquid chromatography, liquid chromatography-mass spectrometry, and thin-layer chromatography, resulting in high testing costs, time-consuming and labor-intensive processes, and difficulty in achieving real-time on-site detection.
[0003] Molecular imprinting technology utilizes specific molecules as templates. During the synthesis of polymers, specific cavity structures are formed within the polymer that interact with the template molecules, leaving behind unique cavities. These cavities can selectively recognize and specifically bind to the template molecules or their analogues, enabling the detection of specific molecules through electrochemical, optical, and thermal signal conversion. This technology has wide applications in chromatographic separation and compound detection. Carbon quantum dots possess excellent optical properties, good water solubility, low toxicity, environmental friendliness, wide availability of raw materials, low cost, and good biocompatibility. They can serve as fluorescently responsive molecularly imprinted polymers. Therefore, it holds promise for using carbon quantum dots as recognition elements to construct molecularly imprinted fluorescent sensors for the detection of tetracycline antibiotics. Summary of the Invention
[0004] To address the shortcomings of existing technologies, the present invention aims to provide a molecularly imprinted fluorescent sensor for detecting tetracycline antibiotics and its preparation method, thereby producing a molecularly imprinted fluorescent sensor with high specificity and sensitivity to tetracycline antibiotics at a low cost.
[0005] To achieve the above objectives, the present invention employs the following technical solution:
[0006] A method for preparing a molecularly imprinted fluorescent sensor for detecting tetracycline antibiotics includes the following steps:
[0007] Step 1: Add 1-5 mmol tetracycline and 4-20 mmol methacrylic acid to 15-50 mL acetonitrile, sonicate to dissolve completely, and prepolymerize at 4-8 °C for 4-6 h to obtain the intermediate product.
[0008] Step 2: Add 8-24 mmol of ethylene glycol dimethacrylate, 0.2-0.6 mmol of azobisisobutyronitrile and 0.02-0.08 g of carbon quantum dots to the intermediate product. After purging the reactor with nitrogen to remove oxygen under ice bath conditions, react at 50-70°C for 20-30 h to obtain the polymer.
[0009] Step 3: Prepare an eluent by mixing acetic acid and methanol at a volume ratio of 1:9. Use the eluent to elute the polymer until the eluent does not contain a tetracycline UV absorption peak as detected by a UV absorber, thus obtaining the molecularly imprinted fluorescent sensor CDs@MIP.
[0010] Furthermore, the ultrasound time in step 1 is 2 to 5 minutes.
[0011] Furthermore, the carbon quantum dots in step 2 are prepared by the following method:
[0012] Step 2.1: Dissolve 1-3 mmol of citric acid and 1.5-6 mmol of thiourea in 20 mL of deionized water, sonicate to dissolve completely, and then transfer to a high-pressure reactor lined with polytetrafluoroethylene. React at 160-200℃ for 8-16 h to obtain reaction solution A.
[0013] Step 2.2: After centrifuging reaction solution A, take the supernatant and add it to a dialysis bag. Dialyze it in deionized water to remove unreacted citric acid and thiourea. Then, vacuum concentrate and freeze dry in sequence to obtain carbon quantum dots (CDs).
[0014] Furthermore, the ultrasound time in step 2.1 is 5 minutes.
[0015] Furthermore, the centrifugation in step 2.2 uses a centrifuge with a speed of 8000 to 12000 rpm.
[0016] Furthermore, the dialysis in step 2.2 is performed using a 44mm×1000kDa dialysis bag for 18–24 hours.
[0017] A molecularly imprinted fluorescent sensor that specifically recognizes and responds to tetracycline antibiotics.
[0018] Compared with the prior art, the present invention has the following technical effects:
[0019] The molecularly imprinted holes on the surface of the fluorescent sensor prepared in this invention can adsorb tetracycline and bind it with weak chemical forces such as hydrogen bonds. The tetracycline absorbs part of the excitation light energy of the fluorescent sensor, weakening the fluorescence of the sensor. Moreover, as the concentration of tetracycline increases, the absorbed excitation light energy increases, eventually leading to fluorescence quenching of the fluorescent sensor. Therefore, the fluorescent sensor prepared in this invention can specifically recognize tetracycline antibiotics, has strong anti-interference ability, and can detect tetracycline antibiotics in livestock and poultry meat and environmental water samples with high sensitivity in a short time. It can be used repeatedly, saving detection costs, improving detection efficiency, and realizing real-time on-site detection of tetracycline antibiotics.
[0020] The raw materials used in this invention are all common and inexpensive, which reduces the manufacturing cost of the fluorescence sensor and makes it suitable for industrial production. It has broad application prospects in the field of analysis and detection of tetracycline antibiotics. Attached Figure Description
[0021] Figure 1 The results of the selectivity experiment of the fluorescent sensor prepared in Example 1 for tetracycline antibiotics;
[0022] Figure 2 The results of the anti-interference experiment of metal ions when the fluorescent sensor prepared in Example 1 detects tetracycline antibiotics;
[0023] Figure 3 The fluorescence responsiveness of the fluorescence sensor prepared in Example 1 under different pH conditions;
[0024] Figure 4 The response time of the fluorescent sensor prepared in Example 1 to tetracycline;
[0025] Figure 5 The results of the recycling verification experiment for the fluorescence sensor prepared in Example 1;
[0026] Figure 6 The fluorescence spectra of the fluorescence sensor and the fitted standard curves are shown in tetracycline solutions of different concentrations. Detailed Implementation
[0027] The specific content of the present invention will be further explained in detail below with reference to the embodiments.
[0028] Example 1
[0029] Step 1: Dissolve 1 mmol of citric acid and 1.5 mmol of thiourea in 20 mL of deionized water, sonicate for 5 min to ensure complete dissolution, then transfer to a high-pressure reactor lined with polytetrafluoroethylene, and react at 160 °C for 16 h to obtain reaction solution A;
[0030] Step 2: Centrifuge reaction solution A at 8000 rpm using a centrifuge, take the supernatant and add it to a dialysis bag with a specification of 44 mm × 1000 kDa. Dialyze in deionized water for 24 h to remove unreacted citric acid and thiourea. Then, vacuum concentrate and freeze dry in sequence to obtain carbon quantum dots CDs.
[0031] Step 3: Add 1 mmol tetracycline and 4 mmol methacrylic acid to a round-bottom flask containing 15 mL acetonitrile, sonicate for 2 min to dissolve completely, and prepolymerize at 4 °C for 4 h to obtain the intermediate product.
[0032] Step 4: Add 8 mmol of ethylene glycol dimethacrylate, 0.2 mmol of azobisisobutyronitrile, and 0.02 g of carbon quantum dots to the intermediate product. Under ice bath conditions, purge the round-bottom flask with nitrogen to remove oxygen and react at 50°C for 30 h to obtain the polymer.
[0033] Step 5: Prepare an eluent by mixing acetic acid and methanol at a volume ratio of 1:9. Use the eluent to elute the polymer until the eluent does not contain a tetracycline UV absorption peak as detected by a UV absorber, thus obtaining the molecularly imprinted fluorescent sensor CDs@MIP.
[0034] Example 2
[0035] Step 1: Dissolve 2 mmol of citric acid and 4.6 mmol of thiourea in 20 mL of deionized water, sonicate for 5 min to ensure complete dissolution, then transfer to a high-pressure reactor lined with polytetrafluoroethylene, and react at 180 °C for 12 h to obtain reaction solution A;
[0036] Step 2: Centrifuge reaction solution A at 10,000 rpm using a centrifuge, take the supernatant and add it to a dialysis bag with a specification of 44 mm × 1000 kDa, dialyze in deionized water for 21 h to remove unreacted citric acid and thiourea, then vacuum concentrate and freeze dry in sequence to obtain carbon quantum dots CDs.
[0037] Step 3: Add 2.5 mmol tetracycline and 12 mmol methacrylic acid to a round-bottom flask containing 30 mL acetonitrile, sonicate for 3 min to dissolve completely, and prepolymerize at 6 °C for 5 h to obtain the intermediate product.
[0038] Step 4: Add 16 mmol of ethylene glycol dimethacrylate, 0.4 mmol of azobisisobutyronitrile, and 0.05 g of carbon quantum dots to the intermediate product. Under ice bath conditions, purge the round-bottom flask with nitrogen to remove oxygen and react at 60 °C for 25 h to obtain the polymer.
[0039] Step 5: Prepare an eluent by mixing acetic acid and methanol at a volume ratio of 1:9. Use the eluent to elute the polymer until the eluent does not contain a tetracycline UV absorption peak as detected by a UV absorber, thus obtaining the molecularly imprinted fluorescent sensor CDs@MIP.
[0040] Example 3
[0041] Step 1: Dissolve 3 mmol of citric acid and 6 mmol of thiourea in 20 mL of deionized water, sonicate for 5 min to ensure complete dissolution, then transfer to a high-pressure reactor lined with polytetrafluoroethylene, and react at 200 °C for 8 h to obtain reaction solution A;
[0042] Step 2: Centrifuge reaction solution A at 12000 rpm using a centrifuge, take the supernatant and add it to a dialysis bag with a specification of 44 mm × 1000 kDa, dialyze in deionized water for 18 h to remove unreacted citric acid and thiourea, then vacuum concentrate and freeze dry in sequence to obtain carbon quantum dots CDs.
[0043] Step 3: Add 5 mmol tetracycline and 20 mmol methacrylic acid to a round-bottom flask containing 50 mL acetonitrile, sonicate for 5 min to dissolve completely, and prepolymerize at 8 °C for 6 h to obtain the intermediate product.
[0044] Step 4: Add 24 mmol of ethylene glycol dimethacrylate, 0.6 mmol of azobisisobutyronitrile, and 0.08 g of carbon quantum dots to the intermediate product. Under ice bath conditions, purge the round-bottom flask with nitrogen to remove oxygen and react at 70°C for 20 h to obtain the polymer.
[0045] Step 5: Prepare an eluent by mixing acetic acid and methanol at a volume ratio of 1:9. Use the eluent to elute the polymer until the eluent does not contain a tetracycline UV absorption peak as detected by a UV absorber, thus obtaining the molecularly imprinted fluorescent sensor CDs@MIP.
[0046] Example 4
[0047] Step 1: Dissolve 1.5 mmol of citric acid and 3.8 mmol of thiourea in 20 mL of deionized water, sonicate for 5 min to ensure complete dissolution, then transfer to a high-pressure reactor lined with polytetrafluoroethylene, and react at 190 °C for 10 h to obtain reaction solution A;
[0048] Step 2: Centrifuge reaction solution A at 11,000 rpm using a centrifuge, take the supernatant and add it to a dialysis bag with a specification of 44 mm × 1000 kDa, dialyze in deionized water for 20 h to remove unreacted citric acid and thiourea, then vacuum concentrate and freeze dry in sequence to obtain carbon quantum dots CDs.
[0049] Step 3: Add 3 mmol tetracycline and 15 mmol methacrylic acid to a round-bottom flask containing 40 mL acetonitrile, sonicate for 4 min to dissolve completely, and prepolymerize at 7 °C for 4 h to obtain the intermediate product.
[0050] Step 4: Add 12 mmol of ethylene glycol dimethacrylate, 0.3 mmol of azobisisobutyronitrile, and 0.04 g of carbon quantum dots to the intermediate product. Under ice bath conditions, purge the round-bottom flask with nitrogen to remove oxygen and react at 60°C for 30 h to obtain the polymer.
[0051] Step 5: Prepare an eluent by mixing acetic acid and methanol at a volume ratio of 1:9. Use the eluent to elute the polymer until the eluent does not contain a tetracycline UV absorption peak as detected by a UV absorber, thus obtaining the molecularly imprinted fluorescent sensor CDs@MIP.
[0052] Example 5
[0053] Step 1: Dissolve 2.5 mmol citric acid and 5.5 mmol thiourea in 20 mL deionized water, sonicate for 5 min to fully dissolve, then transfer to a high-pressure reactor lined with polytetrafluoroethylene, and react at 170 °C for 14 h to obtain reaction solution A;
[0054] Step 2: Centrifuge reaction solution A at 9000 rpm using a centrifuge, take the supernatant and add it to a dialysis bag with a specification of 44 mm × 1000 kDa, dialyze in deionized water for 22 h to remove unreacted citric acid and thiourea, and then vacuum concentrate and freeze dry in sequence to obtain carbon quantum dots CDs.
[0055] Step 3: Add 4 mmol tetracycline and 8 mmol methacrylic acid to a round-bottom flask containing 20 mL acetonitrile, sonicate for 2 min to dissolve completely, and prepolymerize at 5 °C for 5 h to obtain the intermediate product.
[0056] Step 4: Add 20 mmol of ethylene glycol dimethacrylate, 0.5 mmol of azobisisobutyronitrile, and 0.07 g of carbon quantum dots to the intermediate product. Under ice bath conditions, purge the round-bottom flask with nitrogen to remove oxygen and react at 50 °C for 20 h to obtain the polymer.
[0057] Step 5: Prepare an eluent by mixing acetic acid and methanol at a volume ratio of 1:9. Use the eluent to elute the polymer until the eluent does not contain a tetracycline UV absorption peak as detected by a UV absorber, thus obtaining the molecularly imprinted fluorescent sensor CDs@MIP.
[0058] The molecularly imprinted fluorescent sensors prepared in Examples 1 to 5 are all solid powders that can form a uniform dispersion when dispersed in ultrapure water. Under a 365 nm UV lamp, the solution exhibits blue-green fluorescence. The optimal excitation wavelength and the optimal emission wavelength are 410 nm and 505 nm, respectively. When tetracycline antibiotics are added to the solution, the tetracycline antibiotics can be specifically recognized by the molecularly imprinted holes on the sensor surface and adsorbed into the imprinted holes, binding with weak chemical forces such as hydrogen bonds. When irradiated with excitation light, the fluorescence of the fluorescent sensor weakens because the tetracycline absorbs part of the excitation light energy of the fluorescent sensor. When the concentration of tetracycline increases, the absorbed excitation light energy increases, eventually leading to the quenching of the fluorescence of the fluorescent sensor.
[0059] For the performance tests of the molecularly imprinted fluorescent sensor prepared in Example 1, please refer to Examples 6 to 12.
[0060] Example 6
[0061] The selectivity of the molecularly imprinted fluorescent sensor prepared in Example 1 for tetracycline was tested.
[0062] The molecularly imprinted fluorescent sensor prepared in Example 1 was dispersed in ultrapure water to prepare a molecularly imprinted fluorescent sensor solution with a concentration of 1 μg / mL, denoted as solution A. Solution A was first divided into several equal portions, and then these portions were divided into two groups, denoted as group one and group two. Next, deionized water was added to one portion of solution A in group one and group two as a control. Then, equal volumes and concentrations of different types of antibiotic solutions (excluding tetracycline) were added to each portion of solution A in group one and group two, respectively. Then, an equal volume of tetracycline TET solution was added to each solution in group one, and an equal volume of ultrapure water was added to each solution in group two, so that the final volume of each portion of solution in group one and group two was equal.
[0063] The fluorescence intensity changes of each solution in the first and second groups were recorded using a fluorescence spectrometer, and the results are as follows: Figure 1 As shown, only the fluorescence intensity of the solution containing tetracycline was quenched, indicating that the molecularly imprinted fluorescence sensor prepared in Example 1 has a specific recognition ability for tetracycline antibiotics.
[0064] Example 7
[0065] The anti-interference performance of the molecularly imprinted fluorescent sensor prepared in Example 1 against metal ions was determined:
[0066] The molecularly imprinted fluorescent sensor prepared in Example 1 was dispersed in ultrapure water to prepare a molecularly imprinted fluorescent sensor solution with a concentration of 1 μg / mL, denoted as solution A. Solution A was first divided into several equal portions, and then these portions were divided into two groups, denoted as group one and group two. Next, deionized water was added to one portion of solution A in group one and group two as a control. Then, equal volumes and concentrations of different types of metal ion solutions were added to each portion of solution A in group one and group two, respectively. Then, an equal volume of tetracycline (TET) solution was added to each solution in group one, and an equal volume of ultrapure water was added to each solution in group two, so that the final volumes of each portion of solution in group one and group two were equal.
[0067] The fluorescence intensity changes of each solution in the first and second groups were recorded using a fluorescence spectrometer, and the results are as follows: Figure 2 As shown, only the fluorescence intensity of the solution containing tetracycline was quenched, indicating that metal ions did not affect the fluorescence quenching of the molecularly imprinted fluorescence sensor caused by tetracycline. It can be seen that the molecularly imprinted fluorescence sensor prepared in Example 1 has a strong anti-interference ability against metal ions.
[0068] Example 8
[0069] The fluorescence responsiveness of the molecularly imprinted fluorescence sensor prepared in Example 1 at different pH values was determined:
[0070] First, prepare equal volumes of ultrapure water at different pH values. Then, disperse equal volumes of the molecularly imprinted fluorescence sensor prepared in Example 1 in ultrapure water at different pH values to prepare several equal volumes of molecularly imprinted fluorescence sensor solutions with a concentration of 1 μg / mL at different pH values, denoted as solution A. Then, record the fluorescence intensity changes of each solution A using a fluorescence spectrometer. The results are as follows: Figure 3 As shown, the fluorescence of the molecularly imprinted fluorescence sensor is relatively stable under weakly acidic conditions with a pH of 5-7, but unstable under strongly acidic and alkaline conditions.
[0071] Example 9
[0072] The response time of the molecularly imprinted fluorescent sensor prepared in Example 1 to tetracycline was determined:
[0073] The molecularly imprinted fluorescent sensor prepared in Example 1 was dispersed in ultrapure water to prepare a molecularly imprinted fluorescent sensor solution with a concentration of 1 μg / mL, denoted as solution A. Solution A was divided into two equal portions. Tetracycline solution was added to one portion, and an equal volume of ultrapure water was added to the other portion. The changes in fluorescence intensity of the solution were recorded at regular intervals using a fluorescence spectrometer. Figure 4As shown, the fluorescence intensity of solution A with added tetracycline decreased rapidly and stabilized after 90 minutes. This demonstrates that the fluorescence sensor prepared in Example 1 can accurately determine tetracycline after 90 minutes.
[0074] Example 10
[0075] The recyclability of the molecularly imprinted fluorescent sensor prepared in Example 1 was determined:
[0076] The molecularly imprinted fluorescent sensor prepared in Example 1 was dispersed in ultrapure water to prepare a molecularly imprinted fluorescent sensor solution with a concentration of 1 μg / mL, denoted as solution A. Tetracycline solution was added to solution A, and after 90 min, the fluorescence intensity of the solution was measured using a fluorescence spectrometer. Then, solution A containing tetracycline was eluted with an eluent prepared from acetic acid and methanol at a volume ratio of 1:9 until a UV absorption spectrometer detected no tetracycline UV absorption peak in the eluent. The resulting tetracycline-free solution was then reconstituted to a concentration of 1 μg / mL, and tetracycline solution was added again. The fluorescence intensity of the solution was then measured using a fluorescence spectrometer. This process was repeated, and the results are as follows: Figure 5 As shown, after 6 cycles of use, the fluorescence intensity of the molecularly imprinted fluorescence sensor only decreased slightly, indicating that the molecularly imprinted fluorescence sensor prepared in Example 1 can be used repeatedly.
[0077] Example 11
[0078] The detection range and detection limit of the molecularly imprinted fluorescence sensor prepared in Example 1 were determined:
[0079] The molecularly imprinted fluorescent sensor prepared in Example 1 was dispersed in ultrapure water to prepare a solution with a concentration of 1 μg / mL, denoted as solution A. Solution A was divided into several equal portions, and different amounts of tetracycline were added to each portion to form a series of solutions containing different concentrations of tetracycline, denoted as solutions B. After stabilization, the fluorescence intensity of each solution B was recorded using a fluorescence spectrometer. A standard curve was plotted with the natural logarithm of the tetracycline concentration (lnC) as the abscissa and F0 / F as the ordinate, where F0 and F are the initial fluorescence intensity of solution A and the fluorescence intensity of solution B after the addition of tetracycline, respectively. The results are as follows: Figure 6 As shown, the fluorescence of the molecularly imprinted fluorescence sensor is gradually quenched as the tetracycline concentration increases, and the fluorescence intensity ratio F0 / F exhibits a linear correlation with the natural logarithm of the tetracycline concentration, with a linear correlation coefficient r. 2 =0.999, indicating that accurate quantification of tetracycline can be achieved through fluorescence quenching. The detection limit is calculated to be 0.18 ng / mL using 3σ / k, where σ is the standard deviation of the blank sample and k is the slope of the calibration curve.
[0080] Example 12
[0081] The molecularly imprinted fluorescence sensor prepared in Example 1 was used to determine the recovery rate of pork samples.
[0082] First, the molecularly imprinted fluorescent sensor prepared in Example 1 was dispersed in ultrapure water to prepare a solution with a concentration of 1 μg / mL, denoted as Solution A. Then, pork tenderloin was ground into minced meat using an ultrafine grinder. Tetracycline (TET), oxytetracycline (OXY), and chlortetracycline (CTE) were spiked separately. 5g of the spiked minced meat was weighed into centrifuge tubes and added to 10mL of a 2% lead acetate solution. The mixture was thoroughly shaken and vortexed at high speed for 10 minutes, then centrifuged at 8000 rpm for 5 minutes. The supernatant was collected and added to Solution A. Fluorescence intensity changes were recorded using a fluorescence spectrometer. Figure 6 The content of tetracycline antibiotics was calculated using the fitted standard curve, and the results are shown in Table 1. No tetracycline antibiotic residues were found in the unspecified pork, while tetracycline antibiotics were detected in the pork spiked with TET, CTE, and OXY, respectively, with recoveries ranging from 98.0% to 108%. When the three tetracycline antibiotics were spiked simultaneously, the molecularly imprinted fluorescence sensor could detect the total amount of the three antibiotics, with relative standard deviations ranging from 1.23% to 4.95%, indicating that the molecularly imprinted fluorescence sensor prepared in Example 1 can accurately detect tetracycline antibiotics.
[0083] Table 1. Application of molecularly imprinted fluorescence sensor in pork sample detection and results of spiked recovery test.
[0084]
[0085] a mean±std,n=3; b mean±std,n=3; c Not detected.
Claims
1. A method for preparing a molecularly imprinted fluorescent sensor for detecting tetracycline antibiotics, characterized in that, Includes the following steps: Step 1: Take 1-5 mmol of tetracycline and 4-20 mmol of methacrylic acid and add them to 15-50 mL of acetonitrile. Sonicate the solution until it is fully dissolved. Prepolymerize at 4-8 °C for 4-6 h to obtain the intermediate product. Step 2: Add 8-24 mmol of ethylene glycol dimethacrylate, 0.2-0.6 mmol of azobisisobutyronitrile (AIBN), and 0.02-0.08 g of carbon quantum dots to the intermediate product. After purging the reactor with nitrogen to remove oxygen under ice bath conditions, react at 50-70 °C for 20-30 h to obtain the polymer. The carbon quantum dots are prepared by the following method: Step 2.1: Dissolve 1-3 mmol of citric acid and 1.5-6 mmol of thiourea in 20 mL of deionized water, sonicate to dissolve completely, and then transfer to a high-pressure reactor lined with polytetrafluoroethylene. React at 160-200 °C for 8-16 h to obtain reaction solution A. Step 2.2: After centrifuging reaction solution A, take the supernatant and add it to a dialysis bag. Dialyze it in deionized water to remove unreacted citric acid and thiourea. Then, vacuum concentrate and freeze dry in sequence to obtain carbon quantum dots CDs. Step 3: Prepare an eluent by mixing acetic acid and methanol at a volume ratio of 1:
9. Use the eluent to elute the polymer until the eluent does not contain a tetracycline UV absorption peak as detected by a UV absorber, thus obtaining the molecularly imprinted fluorescent sensor CDs@MIP.
2. The method for preparing a molecularly imprinted fluorescent sensor for detecting tetracycline antibiotics according to claim 1, characterized in that, The ultrasound time in step 1 is 2-5 minutes.
3. The method for preparing a molecularly imprinted fluorescent sensor for detecting tetracycline antibiotics according to claim 1, characterized in that, The ultrasound time in step 2.1 is 5 minutes.
4. The method for preparing a molecularly imprinted fluorescent sensor for detecting tetracycline antibiotics according to claim 1, characterized in that, The centrifugation in step 2.2 uses a centrifuge with a speed of 8000~12000 rpm.
5. The method for preparing a molecularly imprinted fluorescent sensor for detecting tetracycline antibiotics according to claim 1, characterized in that, The dialysis in step 2.2 is performed using a 44 mm × 1000 kDa dialysis bag for 18–24 hours.
6. A molecularly imprinted fluorescent sensor prepared by the method according to any one of claims 1 to 5, characterized in that, It exhibits specific recognition and fluorescence response to tetracycline antibiotics.