Construction of a Functional-Free Long Afterglow Ratio Sensor and Its Application in Precise Detection of Tetracycline

Abstract

This invention discloses the construction of a functional-free long-persistence ratio sensor and its application in the accurate detection of tetracycline, belonging to the field of tetracycline detection technology. This invention is based on a functional-free long-persistence ratio sensor, in which Eu serves as both the binding and recognition site for TC and the luminescence center of the material. Through an internal filtering effect, phosphorescence quenching of the PLNP is achieved, and through an antenna effect, Eu on the PLNP is realized. 3+ The fluorescence enhancement was used to construct a one-step synthesized long-persistence ratio sensor. The characteristic emission peaks of this long-persistence ratio sensor are phosphorescence emission at 700 nm and fluorescence emission at 618 nm. This probe does not require functionalization modification and has the advantages of no in-situ excitation, no background interference or external interference, and high specificity. It can detect TC residues in samples with high sensitivity, accuracy and specificity.

Description

Technical Field

[0001] This invention belongs to the field of tetracycline detection technology, specifically relating to the construction of a functional-free long afterglow ratio sensor and its application in the accurate detection of tetracycline. Background Technology

[0002] Tetracycline (TC) is widely used in animal husbandry, aquaculture, and agricultural production due to its low cost, simple synthesis process, and significant antibacterial effects. However, TC is difficult for organisms to fully utilize after being introduced into them; over 75% of TC is excreted unchanged or as metabolites through urine and feces, inevitably entering the aquatic environment and exerting toxic effects on non-target organisms. It poses a potential hazard to aquatic life and can even enter the food chain through bioaccumulation in aquatic animals, thus affecting human health. Therefore, there is an urgent need to develop an accurate and sensitive detection method to monitor tetracycline residues in water and food. This will help control residue levels at the source, thereby effectively ensuring food safety and public health.

[0003] Currently, traditional detection methods, such as colorimetry, high-performance liquid chromatography (HPLC), enzyme-linked immunosorbent assay (ELISA), electrochemical methods, and fluorescence methods, are widely used in the quantitative analysis of tetracycline (TC). Among them, fluorescence detection has attracted much attention due to its significant advantages such as simple operation, rapid detection, and ease of implementation. Currently, various fluorescent materials have been successfully used for high-sensitivity and high-efficiency TC detection, including carbon quantum dots, metal nanoclusters, metal-organic frameworks (MOFs), and covalent organic frameworks (COFs). However, existing fluorescence detection methods generally rely on external light source excitation, making it difficult to avoid autofluorescence interference from complex sample matrices; moreover, introducing recognition units to achieve specific detection results in complex preparation, increased costs, and poor batch-to-batch reproducibility. Therefore, designing a simple construction strategy and developing a novel tetracycline detection method that combines flexibility, selectivity, and high sensitivity, while effectively avoiding autofluorescence and external interference, is of great significance for the analysis of complex samples. Summary of the Invention

[0004] [Technical Issues]

[0005] Most fluorescent methods for tetracycline detection require continuous excitation light, making it difficult to avoid autofluorescence interference from complex sample matrices. This necessitates post-modification to introduce specific recognition units, leading to complex synthesis and poor batch-to-batch reproducibility. Detection using long-persistence materials, however, effectively avoids matrix interference and improves the signal-to-noise ratio due to the absence of continuous excitation. However, current long-persistence-based detection probes often rely on a single emission signal, making the detection results susceptible to errors caused by instrument parameters, detection time, and probe concentration; post-modification processes are also required.

[0006] [Technical Solution]

[0007] To address the aforementioned issues, this invention provides a one-step synthesized, post-modification-free long-persistent-base ratio sensor, and enables rapid and accurate detection of tetracycline based on this long-persistent-base ratio sensor.

[0008] The first objective of this invention is to provide a tetracycline ratio-based spectral analysis method, wherein the method uses a one-step synthesized, functionalization-free long afterglow ratio-based sensor as a detection probe;

[0009] The method for fabricating the one-step synthetic, functionalization-free long afterglow ratio sensor includes the following steps:

[0010] Zinc salt, chromium salt, and europium salt were dissolved in water. Ga2O3 was heated and dissolved in dilute nitric acid solution to obtain Ga(NO3)3 solution. Na2GeO3 was dissolved in dilute ammonia solution to obtain Na2GeO3 solution. Zinc salt, chromium salt, and europium salt were dissolved in water, and Ga(NO3)3 solution, Na2GeO3 solution, and CTAB were added. The mixture was stirred and the pH was adjusted to 8-12 to carry out a hydrothermal reaction. After the reaction was completed, the precipitate was separated and collected, washed, dried, and ground. Then, it was placed in a muffle furnace and heated to 700-1000℃ in an air atmosphere for a period of time. After calcination, it was cooled to obtain a long afterglow ratio sensor.

[0011] The present invention also provides a method for ratiometric spectral analysis of tetracycline in aquatic environments or food, wherein the method uses a long afterglow ratiometric sensor synthesized in one step without functionalization modification as a detection probe.

[0012] In one embodiment of the present invention, the concentration of the NaGeO3 solution is 0.2-0.5 mol / L; specifically, 0.4 mol / L may be selected.

[0013] In one embodiment of the present invention, the concentration of the Ga(NO3)3 solution is 0.2-1.0 mol / L; specifically, 0.4 mol / L may be selected.

[0014] In one embodiment of the present invention, the molar ratio of Zn to Ge in the zinc salt and Na2GeO3 is (1-5):(0.1-0.9). Specifically, 1.1:0.1 may be selected.

[0015] In one embodiment of the present invention, the molar ratio of Ga to Ge in Ga(NO3)3 and Na2GeO3 is (0.1-2):(0.1-0.9). Specifically, 1.8:0.1 may be selected.

[0016] In one embodiment of the present invention, the molar ratio of Ga to Cr in Ga(NO3)3 and the chromium salt is 1:(0.002-0.005). Specifically, 1:0.005 may be selected.

[0017] In one embodiment of the present invention, the molar ratio of Ga to Eu in Ga(NO3)3 and europium salt is (0.003-0.010). Specifically, a ratio of 1:0.008 may be selected.

[0018] In one embodiment of the present invention, the zinc salt is a soluble salt of zinc, specifically Zn(NO3)2·6H2O.

[0019] In one embodiment of the present invention, the europium salt is a soluble salt of europium, specifically Eu(NO3)3·5H2O.

[0020] In one embodiment of the present invention, the chromium salt is a soluble salt of chromium, specifically Cr(NO3)3·6H2O.

[0021] In one embodiment of the present invention, the pH is adjusted to 8.0-10.5 using ammonia water to carry out a hydrothermal reaction.

[0022] In one embodiment of the present invention, the hydrothermal reaction is carried out at 200-220°C for 18-72 hours.

[0023] In one embodiment of the present invention, the molar ratio of CTAB to Na2GeO3 is (0.2-0.5):1.

[0024] In one embodiment of the present invention, the temperature is increased to 700-1000°C in an air atmosphere in a muffle furnace at a heating rate of 2-10°C / min, and then held at that temperature for 2-8 hours. Specifically, the temperature is increased to 900°C in an air atmosphere in a muffle furnace at a heating rate of 5°C / min, and then held at that temperature for 4 hours.

[0025] In the long afterglow ratio sensor of this invention, Eu 3+ This invention presents a strategy for constructing a functional-free long-persistence ratiometric sensor that combines luminescence centers and recognition sites, along with a method for tetracycline (TC) detection. The sensor simultaneously achieves luminescence "decrease" at 700 nm and luminescence "on" at 618 nm, detecting tetracycline through a significant change in the ratio of luminescence intensity at these two wavelengths, thereby effectively removing matrix background fluorescence and external interference. The ratiometric sensor constructed in this invention exhibits advantages such as good stability, strong batch-to-batch repeatability, no sample autofluorescence interference, unaffected by external conditions, high sensitivity, and good selectivity, showing broad prospects for tetracycline detection in food.

[0026] A second objective of this invention is to provide a method for the quantitative detection of tetracycline, comprising the following steps:

[0027] This invention also provides a method for the quantitative detection of tetracycline in aquatic environments or food. The method involves mixing a series of tetracycline standard solutions of known concentrations with a long afterglow ratio sensor and incubating for a period of time. Then, the luminescence intensity at 618±5nm and 700±5nm is measured on a fluorescence spectrometer in fluorescence and phosphorescence modes, respectively, to obtain the luminescence intensities I1 and I2. The luminescence intensity ratio I1 / I2 is calculated. A linear quantitative model is constructed using the concentration of the tetracycline standard sample and the luminescence intensity ratio I1 / I2.

[0028] In one embodiment of the present invention, a long-afterglow ratio sensor is dispersed in Tris-HCl buffer to obtain a long-afterglow ratio sensor solution; the long-afterglow ratio sensor solution is added to a tetracycline standard solution and mixed and incubated.

[0029] In one embodiment of the present invention, the concentration of the long afterglow ratio sensor solution is 0.1-1.0 mg / mL. -1 Further optional: 1.0 mg / mL -1 .

[0030] In one embodiment of the present invention, the tetracycline standard solution is prepared by dissolving tetracycline in Tris-HCl buffer.

[0031] In one embodiment of the present invention, a long afterglow ratio sensor solution, a tetracycline standard solution, and a Tris-HCl buffer are mixed and incubated for a period of time; the volume ratio of the long afterglow ratio sensor solution, the tetracycline standard solution, and the Tris-HCl buffer is 1:1:3.

[0032] In one embodiment of the present invention, the pH of the Tris-HCl buffer solution is 8.0.

[0033] In one embodiment of the invention, the mixing incubation time is 20-40 minutes, preferably 25 minutes.

[0034] In one embodiment of the present invention, the water environment includes: surface water, seawater, groundwater, drinking water, and sediments.

[0035] Specifically, the steps include the following:

[0036] An equal volume of PLNP solution was added to tetracycline solutions with different concentration gradients, and the mixture was shaken and incubated at room temperature for 10-40 min. Then, the phosphorescence emission spectrum and fluorescence emission spectrum of each group of solutions were measured by a fluorescence spectrometer under 254 nm excitation. A standard curve was established with tetracycline concentration as the abscissa and the ratio of the luminescence intensity of the detection probe PLNP at 618 nm to 700 nm as the ordinate.

[0037] In one embodiment of the present invention, the preferred conditions for mixed incubation are: pH 8.0, room temperature, and shaking incubation for 25 min.

[0038] In one embodiment of the present invention, the concentration of the tetracycline standard solution is 0-300 ug / mL. Specifically, 0 ug / mL, 3 ug / mL, 5 ug / mL, 30 ug / mL, 50 ug / mL, 100 ug / mL, 150 ug / mL, 200 ug / mL, 250 ug / mL, and 300 ug / mL can be selected.

[0039] The long-persistence ratio sensor fabricated in this invention possesses unique energy storage characteristics. It can store energy after absorbing excitation light and continuously release phosphorescence after the excitation source is removed, enabling in-situ excitation-free detection. By avoiding continuous external light source irradiation, this material can effectively suppress autofluorescence interference from complex sample matrices, significantly improving the signal-to-noise ratio of the detection signal. However, current detection probes based on long-persistence materials mostly employ a single-signal output mode. This detection method is susceptible to fluctuations in instrument performance and differences in probe concentration, leading to unstable detection results and requiring strict control of complex experimental conditions. Therefore, developing a low-cost, simple-to-fabricate, streamlined, and optically stable long-persistence ratio sensor has become a key direction for overcoming existing technological bottlenecks.

[0040] This invention is based on a functional-free Eu-doped long afterglow material (PLNP) sensor. Utilizing the overlap between the UV absorption spectrum of tetracycline and the excitation spectrum of PLNP, and through the internal filtering effect (IFE), it achieves phosphorescence quenching of the long afterglow material and the interaction between tetracycline and Eu on the long afterglow. 3+ By leveraging the antenna effect (AE) to enhance fluorescence, a functional-free long-persistence ratiometric sensor was constructed for the highly sensitive detection of tetracycline (TC) residues, belonging to the field of spectroscopic analysis technology. The characteristic emission peaks of the constructed long-persistence ratiometric sensor are phosphorescence emission at 700 nm and fluorescence emission at 618 nm. This probe possesses advantages such as no need for in-situ excitation, no background interference or external interference, and high specificity, enabling accurate and specific detection of TC residues in real samples. It demonstrates good application potential in TC detection. This research not only provides new ideas for the design of ratiometric fluorescence sensors but also offers an innovative technical solution for rapid on-site detection of pollutants.

[0041] [Beneficial Effects]

[0042] (1) The sensor combines two wavelengths, phosphorescence emission at 700nm and fluorescence emission at 618nm, to achieve ratio detection of TC. During detection, it can effectively avoid the influence of external factors and probe concentration, thereby improving the accuracy of the detection results.

[0043] (2) The light-emitting center of the sensor has the advantages of recognizing the site, eliminating the need for post-modification, having ratio detection and self-calibration reading, making the sensor construction simpler, the batch repeatability better, and reducing costs. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the long afterglow ratio sensor for detecting tetracycline according to the present invention.

[0045] Figure 2 The excitation-emission-luminescence spectrum of the long afterglow ratio sensor prepared in Example 1 and the ultraviolet absorption spectrum of TC are shown.

[0046] Figure 3 The phosphorescence emission spectrum (a), fluorescence emission spectrum (b), and standard curve (c) of the long afterglow ratio sensor for different concentrations of tetracycline in Example 2;

[0047] Figure 4 This is a specificity analysis diagram of the long afterglow ratio sensor in Example 3 for different interfering substances.

[0048] Figure 5 For the buffer and pH effect on the sensor under the detection conditions of Example 5 (I) 618 / I 700 The impact of ).

[0049] Figure 6 For the time-to-sensor (I) under the detection conditions of Example 5 618 / I 700 The impact of ).

[0050] Figure 7 This is an inter-batch stability test under the test conditions of Example 6. Detailed Implementation

[0051] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explanation of the present invention and are not intended to limit the present invention.

[0052] Example 1

[0053] A method for fabricating a long afterglow ratio sensor for detecting tetracycline specifically includes the following steps:

[0054] (1) Synthesis of long afterglow nanomaterials:

[0055] Zn1.1Ga1.8Ge0.1O4:0.5% Cr 3+ 0.8% Eu 3+ It is formed by combining hydrothermal sintering with air.

[0056] Ga2O3 was dissolved in dilute nitric acid solution under hydrothermal conditions at 150℃ to obtain Ga(NO3)3 solution (concentration 0.4 mol / L); Na2GeO3 was dissolved in 3% dilute ammonia solution to obtain Na2GeO3 solution (concentration 0.4 mol / L).

[0057] Dissolve 4.59 mmol Zn(NO3)2·6H2O, 0.0375 mmol Cr(NO3)3·6H2O, and 0.0600 mmol Eu(NO3)3·5H2O in 20 mL of water. Add Ga(NO3)3 solution, Na2GeO3 solution, and 0.088 mmol CTAB, and mix vigorously to form a mixture. In the mixture, Zn 2+ The molar amount is 4.59 mmol, Ga 3+ The molar amount is 7.5 mmol, Cr 3+ The molar amount is 0.0375 mmol, Eu 3+ The molar amount is 0.0600 mmol, Ge 4+ The molar amount is 0.417 mmol (i.e., the molar ratio of Zn, Ga, and Ge in Zn(NO3)2·6H2O, Ga(NO3)3, and Na2GeO3 is 1.1:1.8:0.1, Cr 3+ / Ga 3+ The molar ratio is 0.5%, Eu 3+ / Ga 3+ The molar ratio of Cr was 0.8%; the resulting mixture was adjusted to pH 8.0 with 28% concentrated ammonia solution, stirred at room temperature for 3 h, and then sealed and reacted in a high-pressure reactor at 220℃ for 24 h; after the reaction, the precipitate was separated and collected, washed successively with ultrapure water and ethanol, and dried at 70℃ for 4 h; finally, the obtained powder was wet-ground with an agate mortar and pestle for 30 min, placed in a crucible, heated to 900℃ in a muffle furnace under air atmosphere at a heating rate of 5℃ / min, calcined for 4 h, and then cooled with the furnace, successfully synthesizing Zn1.1Ga1.8Ge0.1O4:0.5% Cr 3+ 0.8% Eu 3+ Long-afterglow nanoparticles are long-afterglow ratiometric sensor probes.

[0058] The obtained long-persistence ratio type sensor probe was subjected to performance testing, and the test results are as follows:

[0059] Figure 2 For long afterglow ratio type sensor probe spectrum; from Figure 2 It can be seen that the overlap between the synthesized long afterglow nanomaterial and the ultraviolet absorption of tetracycline at 254 nm excitation verifies the feasibility of the experiment.

[0060] Example 2: Application of PLNP sensor for tetracycline detection

[0061] A long-afterglow ratiometric spectroscopic method for detecting tetracycline is based on PLNP and Eu, nanomaterials with phosphorescent emission (700 nm) and long afterglow. 3+ A ratiometric detection method for materials based on fluorescence emission (618 nm) is used to achieve ratiometric detection of tetracycline.

[0062] Construction of a long afterglow ratio-based spectral analysis method:

[0063] Preparation of tetracycline standard solutions: Add different amounts of tetracycline to Tris-HCl (pH 8.0) and dissolve completely to obtain a series of tetracycline standard solutions of different concentrations.

[0064] The long afterglow ratiometric sensor probe (PLNP) obtained in Example 1 was dispersed in Tris-HCl (pH 8.0) to prepare a 1 mg / mL solution. -1 PLNP solution.

[0065] A series of tetracycline standard solutions, PLNP solutions, and Tris-HCl (pH 8.0) of varying concentrations were mixed and incubated with shaking at room temperature for 25 min to form a detection system. Subsequently, the phosphorescence and fluorescence spectra of each detection system were measured using a fluorescence spectrometer (F7000). Each detection system was measured three times, and the enhanced fluorescence intensity I at 618 nm was obtained. 618 Luminescence intensity I compared to the phosphorescence intensity at 700 nm 700 The ratio I between the two was calculated. 618 / I 700 Using the ratio I 618 / I 700 A standard curve was constructed using the concentrations of the corresponding tetracycline standard solutions.

[0066] The specific test procedure for detecting tetracycline using a long afterglow ratio sensor probe:

[0067] 200 μL of tetracycline standard solutions (0 μg / mL, 3 μg / mL, 5 μg / mL, 30 μg / mL, 50 μg / mL, 100 μg / mL, 150 μg / mL, 200 μg / mL, 250 μg / mL, 300 μg / mL) were mixed with 200 μL of PLNP (1 mg / mL) obtained in Example 1. -1Mix the tetracycline standard solutions and bring the volume to 1 mL with Tris-HCl buffer (pH 8.0). The final tetracycline concentrations in the system are (0 μg / mL, 0.6 μg / mL, 1 μg / mL, 6 μg / mL, 10 μg / mL, 20 μg / mL, 30 μg / mL, 40 μg / mL, 50 μg / mL, 60 μg / mL). Incubate the mixture at room temperature with shaking for 25 minutes. Then, disperse the resulting solution uniformly and measure the luminescence intensity at 618 nm and 700 nm, respectively, using an F-7000 fluorescence spectrometer in phosphorescence and fluorescence modes. Construct a graph with the tetracycline standard solution concentration as the x-axis and the luminescence intensity ratio (I0) as the x-axis. 618 / I 700 () represents the linear relationship of the vertical axis.

[0068] Figure 3 The emission spectra and standard curves of a long afterglow ratio sensor for different concentrations of tetracycline; from Figure 4 It can be seen that the recovered luminescence intensity I of the detection signal from PLNP at 618 nm is... 618 With the quenching luminescence intensity from 700 nm (I 700 The ratio and TC concentration showed a good linear relationship in the concentration range of 0.18 ug / mL to 60 ug / mL, with a detection limit of 0.055 ug / mL.

[0069] Example 3 Specificity Study

[0070] The PLNP solution obtained in Example 1 was mixed with common ions, amino acids, antibiotics, and other interfering substances (Na+). + K + Mg 2+ Zn 2+ The effects of Aspartic acid, Glutamic acid, Proline, Lysine, Sucr, CAP, and AM on tetracycline detection were investigated. The results showed that these interfering substances affected the detection of tetracycline. 618 / I 700 The response values ​​of all of them are significantly smaller than the response value of TC. Figure 4 This indicates that the detection method has good selectivity and can effectively resist the influence of common interfering substances in actual samples. After shaking and incubating at room temperature for 25 min, the emission spectrum and emission intensity of each solution were tested by a fluorescence spectrometer (F7000).

[0071] Figure 4 This is a specificity analysis diagram for different interfering substances; from Figure 4 It can be seen that: in solutions where only the target analyte tetracycline is present, I 618 / I 700The significant changes observed, with response values ​​in other groups of solutions where the target substance was absent being significantly lower than those of TC, indicate that this method has high specificity and is suitable for the specific detection of tetracycline.

[0072] Example 4 Accuracy Study

[0073] Sample extracts were obtained by pretreating different water environments or actual food samples. Tetracycline standards of the same concentration were prepared in different sample extracts and mixed with PLNP obtained in Example 1. The mixture was then incubated at room temperature with shaking for 25 min. Subsequently, the emission spectrum and emission intensity of each solution were tested by a fluorescence spectrometer (F7000).

[0074] Table 1 shows the accuracy of the method. The recovery rate of TC in the four actual samples ranged from 93.39% to 108.48%, which indicates that the method has high accuracy and can be applied to the sensitive detection of TC in actual samples.

[0075] Table 1. Determination and analysis of TC in food samples

[0076]

[0077] Example 5: Selection of pH and reaction time

[0078] The pH values ​​of Tris-HCl and HEPES used in Example 2 were adjusted to 7.4, 7.6, 7.8, 8.2, and 8.4, respectively, while other parameters remained the same as in Example 2. The detection results of PLNP for TC were obtained as follows:

[0079] Figure 5 pH of Tris-HCl and HEPES for the sensor I 618 / I 700 The impact; from Figure 5 It can be seen that when the pH of the Tris-HCl detection system is 8.0, the detection result I is obtained. 618 / I 700 All values ​​were higher than other pH values, indicating that the response value was the highest. Therefore, the detection was more sensitive when the Tris-HCl used for the test was at pH 8.0.

[0080] The incubation time in Example 2 was adjusted to 5, 10, 15, 20, 30, 35, and 40 minutes, while other parameters remained the same as in Example 2. The detection results of PLNP for TC are as follows:

[0081] Figure 6 For the reaction time of the sensor I 618 / I 700 The impact; from Figure 6It can be seen that adjusting the reaction time to 5, 10, 15, 20, 30, 35, and 40 min yields different detection results I. 618 / I 700 The temperature rises slowly before 25 minutes and then levels off. Therefore, the test results are better after 25 minutes of incubation.

[0082] Example 6: Batch Repeatability Test

[0083] The performance of different batches of materials after reacting with TC was investigated. According to Example 1, five batches of materials were synthesized and incubated with an equal amount of TC under the same conditions as in Example 2 at room temperature with shaking for 25 min. Subsequently, the emission spectrum and emission intensity of each group of solutions were tested by a fluorescence spectrometer (F7000). Figure 7 This demonstrates the repeatability and reliability of the material preparation process.

[0084] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A method of ratio-type spectral analysis of tetracyclines, characterized in that, The method employs a one-step synthesized, functionalization-free long afterglow ratio sensor as a detection probe. The method for fabricating the one-step synthetic, functionalization-free long afterglow ratio sensor includes the following steps: Ga2O3 was dissolved in dilute nitric acid solution by heating to obtain Ga(NO3)3 solution; Na2GeO3 was dissolved in dilute ammonia solution to obtain Na2GeO3 solution; zinc salt, chromium salt and europium salt were dissolved in water, and Ga(NO3)3 solution, Na2GeO3 solution and CTAB were added, mixed well, and the pH was adjusted to 8-12 to carry out hydrothermal reaction; after the reaction was completed, the precipitate was separated and collected, washed, dried and ground, and then placed in a muffle furnace and heated to 700-1000 ℃ in air atmosphere for a period of time. After calcination, it was cooled to obtain a long afterglow ratio sensor. The molar ratio of Zn to Ge in zinc salts and Na2GeO3 is (1-5):(0.1-0.9). The molar ratio of Ga to Ge in Ga(NO3)3 and Na2GeO3 is (0.1-2):(0.1-0.9). The molar ratio of Ga to Cr in Ga(NO3)3 and chromium salt is 1:(0.002-0.005). The molar ratio of Ga to Eu in Ga(NO3)3 and europium salts is 1:(0.003-0.010).

2. The method of claim 1, wherein, The concentration of NaGeO3 solution is 0.2-0.5 mol / L; the concentration of Ga(NO3)3 solution is 0.2-1.0 mol / L.

3. The method of claim 1, wherein, The molar ratio of CTAB to Na2GeO3 is (0.2-0.5):

1.

4. The method according to any one of claims 1 to 3, characterized in that, Heating to 700-1000 ℃ in an air atmosphere in a muffle furnace at a heating rate of 2-10℃ / min, and holding for calcination for 2-8 h.

5. A method for quantitative detection of tetracycline in aquatic environment or food, wherein the method comprises mixing a series of tetracycline standard solutions of known concentrations with the long afterglow ratio sensor described in claim 1 and incubating for a period of time, and then measuring the luminescence intensity at 618±5 nm and 700±5 nm respectively in fluorescence and phosphorescence modes on a fluorescence spectrometer to obtain the corresponding luminescence intensity. I 1. I 2. The ratio of luminous intensity was calculated. I 1 / I 2; The ratio of tetracycline standard sample concentration to luminescence intensity I 1 / I 2. Construct a linear quantitative model.

6. The method of claim 5, wherein, The long-afterglow ratio sensor was dispersed in Tris-HCl to obtain a long-afterglow ratio sensor solution; the long-afterglow ratio sensor solution was added to a tetracycline standard solution and mixed and incubated; the pH of Tris-HCl was 8.0; the incubation time was 20-40 min.

Images