Preparation and application of N, P-doped titanium carbide nanometer quantum dot fluorescent probe
By preparing N,P-doped titanium carbide nanoquantum dot fluorescent probes, the problem of complex and expensive tetracycline detection using traditional methods has been solved. This enables rapid, highly specific, and highly accurate detection of tetracycline in food, with a wide detection range and low detection limit, making it suitable for practical samples.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NORTHWEST NORMAL UNIVERSITY
- Filing Date
- 2024-04-17
- Publication Date
- 2026-07-07
AI Technical Summary
Existing technologies are insufficient for rapid, highly specific, and highly accurate detection of tetracycline residues in food. Traditional methods are complex to operate and require expensive instruments and professional personnel.
Using N,P-doped titanium carbide nanoquantum dot fluorescent probes, N,P-Ti3C2MXene quantum dots smaller than 10 nm were prepared by hydrothermal method. By utilizing their optical properties and fluorescence characteristics, combined with doping with ethylenediamine and diammonium phosphate, the fluorescence intensity and quantum yield were improved, achieving high selectivity and sensitivity for the detection of tetracycline.
It achieves highly selective and sensitive detection of tetracycline, with a detection range of 4.1~114.4 μM and a low detection limit of 1.35 μM. It can effectively avoid interference from coexisting substances and is suitable for the detection of actual food samples.
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Figure CN118440698B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of fluorescence sensor technology, and relates to the preparation of an N,P-doped titanium carbide nanoquantum dot fluorescent probe and its application in the detection of tetracycline. Background Technology
[0002] Tetracycline is a broad-spectrum antibiotic that inhibits bacterial protein synthesis and is effective against both Gram-positive and Gram-negative bacteria. Therefore, it is widely used in human treatment, animal husbandry, and aquaculture. However, due to the inappropriate use of tetracycline, it remains in various foods, including milk, fish, meat, eggs, and honey, causing serious harm to human health, such as liver damage, yellowing teeth, tetracycline resistance, and intestinal flora imbalance. The detection of tetracycline residues remains a major food safety issue.
[0003] Due to the serious hazards of tetracycline, many countries have stipulated maximum residue limits for tetracycline in various agricultural products and foods. For example, the Chinese national standard GB / T22990-2008 stipulates that the tetracycline content in milk must not exceed 5 μg / kg. There are many methods for detecting tetracycline, such as microbiological methods, enzyme-linked immunosorbent assay (ELISA), liquid chromatography, and capillary electrophoresis. These methods offer high precision and accuracy, but most involve complex pretreatment procedures, long detection times, and require expensive equipment and specialized personnel, thus failing to meet the requirements for rapid and highly specific detection of tetracycline content.
[0004] MXene quantum dots possess many interesting optical properties, such as light absorption, photoluminescence, and electrochemiluminescence, and have attracted widespread attention for applications in multi-peak detection optoelectronic devices, biomedicine, and catalysis. MXene quantum dots typically exhibit sizes below 10 nm and thicknesses ranging from monolayers to very few layers. They display efficient light absorption in the ultraviolet, visible, and near-infrared regions, attributed to their tunable electronic bandgap size. They can also convert absorbed energy into other forms, such as thermal or chemical energy. MXene quantum dots exhibit strong excitation-dependent fluorescence emission upon excitation at different wavelengths in the 355–505 nm range, primarily due to size effects and surface defects. This property of MXene quantum dots is particularly utilized in many in vitro and in vivo imaging applications.
[0005] Therefore, it is necessary to combine the photoluminescence properties of MXene quantum dots to provide a quantum dot fluorescent probe that can effectively detect tetracycline. Summary of the Invention
[0006] The purpose of this invention is to provide a method for preparing N,P-doped titanium carbide nanoquantum dot fluorescent probes to improve the fluorescence and quantum yield of Ti3C2MXene quantum dots, thereby achieving high selectivity and sensitive detection of tetracycline (TC).
[0007] A method for preparing an N,P-doped titanium carbide nanoquantum dot fluorescent probe includes the following steps:
[0008] 1) Disperse Ti3AlC2 in HF and stir at 30~35℃ for 40~48h to obtain a black suspension. Centrifuge the obtained black suspension at 7000~8000 rpm for 5~10min and wash the black suspension with deionized water until neutral. Dry the obtained black solid in a vacuum drying oven at 60℃ for 24~36h to obtain single-layer or multi-layer Ti3C2Tx powder; the mass concentration of Ti3AlC2 in HF is 0.05~0.1 g / ml.
[0009] 2) Disperse Ti3C2Tx powder in deionized water, sonicate for 15-24 hours and freeze dry to obtain Ti3C2-Mxene nanosheets; the mass concentration of Ti3C2Tx in deionized water is 0.015-0.025 g / ml.
[0010] 3) Dissolve Ti3C2-Mxene and diammonium phosphate in deionized water and sonicate for 30-45 min. Then add ethylenediamine to the mixture and perform a hydrothermal reaction at 120-160℃ for 4-8 h. Filter the solution using a 220 nm polyethersulfone needle filter and dialyze the resulting filtrate in a dialysis bag with a molecular weight retention of 1000 Da for 10-12 h to obtain N,P-Ti3C2MXene. The mass ratio of Ti3C2-Mxene to diammonium phosphate is 1:1 to 1.5:1, the mass concentration of diammonium phosphate in deionized water is 0.01-0.015 g / ml, and the amount of ethylenediamine (99.1%) added to every 10 ml of the mixture is 0.5-1 ml.
[0011] The synthesis mechanism of this invention involves hydrothermal cleaving of layered Ti3C2-Mxene into quantum dots smaller than 10 nm to impart optical characteristics. Nitrogen and phosphorus elements are incorporated during the hydrothermal reaction, and the co-doping of N and P elements modulates the structure and composition of the MQDs. Furthermore, this may stem from the synergistic effect of the surface chemistry, edge effects, and lateral size of the MQDs in different reaction solvents, leading to higher fluorescence intensity and higher quantum yield.
[0012] Another object of the present invention is to provide the application of N,P-doped Ti3C2MXene quantum dot fluorescent probes in the detection of tetracycline.
[0013] When detecting tetracycline (TC), different concentrations of tetracycline (TC) to be detected are added to the above fluorescent probe, and the intensity of the fluorescence emission peak of the fluorescent probe at 420 nm is measured by the test system at an excitation wavelength of 330 nm.
[0014] Experimental data show that the detection range of the fluorescent probe tetracycline (TC) of this invention is 4.1~114.4 μM, and the limit of detection is 1.35 μM.
[0015] Furthermore, the fluorescent probe based on N,P-Ti3C2MXene quantum dots provided by this invention exhibits high selectivity, effectively avoiding coexistence with other antibiotics (oxytetracycline, doxycycline, pefloxacin), small biological molecules (glutathione, L-cysteine, L-phenylalanine, ascorbic acid, histidine), rutin, folic acid, and ions (Ca). 2+ Zn 2+ Mn 2+ K + Fe 3+ Interference.
[0016] In summary, this invention synthesized blue-emitting N,P-doped Ti3C2MXene quantum dots using ethylenediamine and diammonium hydrogen phosphate as nitrogen and phosphorus sources, respectively, and achieved quantitative detection of tetracycline (TC) based on the quenching effect of its fluorescence. This method exhibits good selectivity and a wide linear range, providing a novel approach for the sensitive detection of tetracycline (TC), and can effectively detect tetracycline (TC) in actual milk samples. Attached Figure Description
[0017] Figure 1 This is a high-magnification transmission electron microscope image of the N,P-Ti3C2MXene quantum dots of this invention;
[0018] Figure 2 This is a histogram of the particle size distribution of the N,P-Ti3C2MXene quantum dots under high magnification transmission according to the present invention.
[0019] Figure 3 The images show a fluorescence comparison of N,P-Ti3C2MXene quantum dots, N-Ti3C2MXene quantum dots, and P-Ti3C2MXene quantum dots from this invention.
[0020] Figure 4 The fluorescence response diagrams of the N,P-Ti3C2MXene quantum dots of this invention under different concentrations of tetracycline (TC) are shown.
[0021] Figure 5 Linear graph of tetracycline (TC) detection.
[0022] Figure 6The effect of different interfering substances on the intensity of fluorescent probes Detailed Implementation
[0023] The present invention will be further explained and described below with reference to specific embodiments.
[0024] Example 1
[0025] Preparation of Ti3C2MXene: The aluminum layer of bulk Ti3AlC2 powder was etched using HF acid to obtain multilayer Ti3C2Tx (Tx = OH, O, or F). The specific steps were as follows: 1 g of Ti3AlC2 was dispersed in a polytetrafluoroethylene beaker containing 20 ml of HF (40%), stirred at 35°C for 48 h to obtain a black suspension. The black suspension was centrifuged at 8000 rpm for 5 min and washed with deionized water until neutral. The resulting black solid was dried in a vacuum drying oven at 60°C for 24 h. 0.5 g of the dried Ti3C2Tx powder was taken, dispersed in 100 ml of deionized water, sonicated for 18 h, and then freeze-dried to further obtain Ti3C2MXene nanosheets.
[0026] Preparation of N,P-Ti3C2MXene quantum dots: 0.3 g of prepared Ti3C2-MXene powder, 0.2 g of diammonium phosphate (DAP), and 20 mL of deionized (DI) water were mixed and sonicated for 30 min. The solution was then transferred to a 50 mL hydrothermal reactor, and 2.0 mL of EDA was added. The hydrothermal reaction was carried out at 120°C for 6 h. Afterward, the solution was filtered through a 220 nm polyethersulfone needle filter, and the resulting solution was further dialyzed for 12 h in a dialysis bag (retaining molecular weight: 1000 Da) to obtain stable N,P-Ti3C2MXene quantum dot fluorescent probes.
[0027] Structural characterization such as Figure 1 As shown, simultaneously by Figure 2 It can be seen that its particle size distribution is between 2.5 and 3.0 nm.
[0028] Example 2
[0029] N-Ti3C2MXene was prepared using the preparation method of Ti3C2MXene in Example 1.
[0030] Preparation of N-Ti3C2MXene quantum dot fluorescent probe: 0.3 g of prepared Ti3C2-MXene powder was mixed with 20 mL of deionized (DI) water and sonicated for 30 min. The solution was then transferred to a 50 mL hydrothermal reactor, and 2.0 mL of EDA (99.1%) was added. The hydrothermal reaction was carried out at 120 °C for 6 h. Afterward, the solution was filtered through a 220 nm polyethersulfone needle filter, and the resulting solution was further dialyzed for 12 h in a dialysis bag (retaining molecular weight: 1000 Da) to obtain the N-Ti3C2MXene quantum dot fluorescent probe.
[0031] Example 3
[0032] P-Ti3C2MXene was prepared using the preparation method of Ti3C2MXene in Example 1.
[0033] Preparation of P-Ti3C2MXene quantum dot fluorescent probes: 0.30 g of prepared Ti3C2-MXene powder, 0.2 g of diammonium phosphate (DAP), and 20 mL of deionized (DI) water were mixed and sonicated for 30 minutes. The solution was then transferred to a 50 mL hydrothermal reactor and hydrothermally reacted at 120 °C for 6 h. Afterward, the solution was filtered through a 220 nm polyethersulfone needle filter, and the resulting solution was further dialyzed for 12 h in a dialysis bag (retaining molecular weight: 1000 Da) to obtain P-Ti3C2MXene quantum dots.
[0034] like Figure 3 As shown, when nitrogen and phosphorus sources are simultaneously doped into Ti3C2MXene quantum dots, their fluorescence is enhanced by 2 to 3 times compared to Ti3C2, N-Ti3C2 and P-Ti3C2 quantum dots.
[0035] The N,P-Ti3C2MXene quantum dot fluorescent probe prepared in Example 1 was used for tetracycline detection experiments.
[0036] Detection of tetracycline (TC): 200 μL of tetracycline (TC) at different concentrations (4.1, 7.2, 8.7, 11.8, 14.7, 17.5, 20.2, 26.7, 36.2, 41.6, 47.6, 55.0, 63.2, 70.6, 80.3, 91.2, 100.2, 114.4 μM) was added to the N,P-Ti3C2MXene quantum dot fluorescent probe mixed solution prepared in Example 1. After reacting for 10 min, the intensity of the fluorescence emission peak of the fluorescent probe at 420 nm was measured at an excitation wavelength of 330 nm. Figure 4 As shown, the fluorescence of the N,P-Ti3C2MXene quantum dot probe gradually decreases with increasing tetracycline (TC) concentration. Figure 5As shown, the fluorescence intensity showed a linear relationship with tetracycline (TC) concentration, with a linear range of 4.1 μM to 114.4 μM, and a detection limit (LOD = 3σ / K). Sv (σ is the standard deviation of the blank sample) is 1.35 μmol.
[0037] The N,P-Ti3C2MXene quantum dot fluorescent probe prepared in Example 1 was used to conduct a tetracycline detection selectivity experiment.
[0038] Validation of high selectivity for tetracycline (TC) detection: 200 μL of 114.4 μM tetracycline (TC) and interfering substances with concentrations ten times higher than tetracycline were added to the N,P-Ti3C2MXene quantum dot fluorescent probe mixed solution prepared in Example 1: antibiotics (oxytetracycline, doxycycline, pefloxacin), small biological molecules (glutathione, L-cysteine, L-phenylalanine, ascorbic acid, histidine), rutin, folic acid, and ions (Ca). 2+ Zn 2+ Mn 2+ K + Fe 3+ The fluorescence response of the N,P-Ti3C2MXene quantum dot fluorescent probe was determined.
[0039] The results are as follows Figure 6 As shown, the fluorescence response intensity for tetracycline differs significantly from that of other interfering substances, thus allowing for a direct detection of tetracycline content in various samples, such as milk.
[0040] N,P-Ti3C2MXene quantum dot fluorescent probe for detecting tetracycline in milk:
[0041] First, 1% (v / v) trichloroacetic acid and chloroform were added to the milk stock solution, and the mixture was vortexed for 3-5 min to remove organic matter such as proteins and lipids. Next, the sample was sonicated for 20 min and centrifuged at 12000 rpm for 10 min. The supernatant was then filtered through a 0.22 μM filter. In the standard addition recovery experiment, different concentrations of TC (including 4.1, 11.8, and 17.5 μM TC) were added to the milk sample. The intensity of the fluorescence emission peak of the fluorescent probe at 420 nm was measured at an excitation wavelength of 330 nm to calculate the recovery rate. The results are shown in Table 1.
[0042] Table 1. Detection results of tetracycline (TC) in milk
[0043]
[0044] 'a' represents the average value calculated based on three measurements.
Claims
1. The application of an N,P-doped titanium carbide nanoquantum dot fluorescent probe in the detection of tetracycline, characterized in that, The sample containing tetracycline to be detected was added to the N,P-doped titanium carbide nanoquantum dot fluorescent probe, and the intensity of the fluorescence emission peak of the fluorescent probe at 420 nm was tested at an excitation wavelength of 330 nm. The preparation method of the N,P-doped titanium carbide nanoquantum dot fluorescent probe includes the following steps: 1) Disperse Ti3AlC2 in HF and stir at 30~35℃ for 40~48h to obtain a black suspension. Centrifuge the obtained black suspension at 7000~8000 rpm for 5~10min and wash the black suspension with deionized water until neutral. Dry the obtained black solid in a vacuum drying oven at 60℃ for 24~36h to obtain single-layer or multi-layer Ti3C2Tx powder. 2) Disperse Ti3C2Tx powder in deionized water, sonicate for 15-24 hours, and freeze-dry to obtain Ti3C2-Mxene nanosheets; 3) Dissolve Ti3C2-Mxene and diammonium phosphate in deionized water and sonicate for 30-45 min. Then add ethylenediamine to the mixture at a rate of 0.5-1 mL per 10 mL of mixture. Perform hydrothermal reaction at 120-160 °C for 4-8 h. Filter the solution using a 220 nm polyethersulfone needle filter. Dialyze the resulting filtrate in a dialysis bag with a molecular weight retention of 1000 Da for 10-12 h to obtain N,P-Ti3C2Mxene. The mass ratio of Ti3C2-Mxene to diammonium phosphate is 1:1 to 1.5:1, and the mass concentration of diammonium phosphate in deionized water is 0.01-0.015 g / mL.
2. The application of the N,P-doped titanium carbide nanoquantum dot fluorescent probe as described in claim 1 in the detection of tetracycline, characterized in that, In step 1), the mass concentration of Ti3AlC2 in HF is 0.05~0.1 g / mL.
3. The application of the N,P-doped titanium carbide nanoquantum dot fluorescent probe as described in claim 1 in the detection of tetracycline, characterized in that, In step 2), the mass concentration of Ti3C2Tx in deionized water is 0.015~0.025 g / mL.