A turn-on fluorescent polymer, a synthesis method thereof and application thereof to detecting uranyl ions

Abstract

The present application belongs to the technical field of environmental detection, and particularly relates to a Turn-On type fluorescent polymer, a synthesis method thereof and application of the fluorescent polymer in detecting uranyl ions. The present application ingeniously uses the structural characteristics of tetraphenyl ethylene tetracarboxaldehyde to synthesize a fluorescent polymer TPE-COPs having a fluorescence enhancement response to uranyl ions at normal temperature. The fluorescent polymer is a "Turn-On" type fluorescent polymer, has advantages of high sensitivity, high selectivity and rapid response in detecting uranyl ions, can simultaneously improve the sensitivity and anti-interference ability, realizes all-round consideration of the detection limit, the detection range and the selectivity, and shows great potential and value in biomedical research and application. Meanwhile, the fluorescent polymer TPE-COPs of the present application can be completed at room temperature, has a simple process, does not need harsh environments such as high temperature, high pressure and oxygen-free, and is more suitable for industrial scale production application.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of environmental detection, and particularly relates to a Turn-On type fluorescent polymer, a synthesis method thereof and application of the Turn-On type fluorescent polymer in detecting uranyl ions. BACKGROUND

[0002] Energy, as the basis of human life development, is crucial in promoting global economic and environmental development. However, with the shortage of fossil energy and the increasing severity of environmental pollution prevention and control, traditional fossil energy has not been able to fully meet the economic demand of modern rapid development. Therefore, it is urgent to seek new energy that can promote economic development and reduce carbon emissions. Among them, nuclear energy, as a zero-carbon energy, can generate zero-emission electricity, which is the best choice for energy structure transformation.

[0003] With the rapid development of nuclear energy industry, the discharge of nuclear waste water has attracted global attention and strong panic due to its serious radiation hazards to the ecological environment. Among them, uranium, as an important radionuclide, plays an irreplaceable role in nuclear fission and nuclear weapons. However, once the unregulated uranium migrates to the environment, its potential radioactivity and chemical toxicity may cause various irreversible damage to human health, such as cell damage, kidney disease, osteosarcoma and liver disease, and even death. Obviously, in order to ensure radiation protection and nuclear safety, timely warning of uranium pollution in environmental samples is required.

[0004] Therefore, in order to meet the needs of uranium pollution early warning in emergency situations, it is desirable and necessary to use sensitive and rapid visual detection strategies in the field instead of complex laboratory detection methods (such as inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma atomic emission spectrometry (ICP-AES), and surface-enhanced Raman spectroscopy (SERS)). Fluorescent methods such as semiconductor quantum dots (QDs), metal-organic frameworks (MOFs), and covalent organic frameworks (COFs) have the advantages of low cost, high efficiency, and ease of use, especially in naked-eye detection, and have been used for rapid detection of uranium. However, semiconductor quantum dots (QDs) and metal-organic frameworks (MOFs) require metal ions as nodes, which are toxic and have complex preparation and modification steps, resulting in poor selectivity, which hinders the widespread application of these methods. Covalent organic frameworks (COFs) are a class of crystalline porous polymers with tunable porosity and large specific surface area, providing convenient conditions for the extraction and detection of radionuclides. However, the synthesis of COFs often requires an oxygen-free, high-temperature environment, and the reaction conditions are highly dependent on the reactivity, solubility, and extent of the reaction of the organic building blocks, making it difficult to obtain excellent crystalline COFs. Porous organic polymers (POPs) are a type of organic porous material with microporous or mesoporous structures, mainly composed of light elements such as C, H, O, and N covalently linked. Porous organic polymers have the characteristics of low skeletal density, tunable porosity, large specific surface area, and good physical and chemical stability, so they can interact well with guest molecules through non-covalent interactions, which has led to the rapid development of POPs in gas separation, storage, pollutant removal, and sensing. Compared with traditional small molecule sensors, POPs are insoluble in water and most organic solvents, which is beneficial for their separation, regeneration, and reuse. In addition, the porous nature of porous organic polymers can provide a rich microenvironment for guest molecules to interact, and the amorphous porous organic polymers have lower crystallinity and weaken the non-radiative transition caused by π-π stacking interactions between molecular layers, which is conducive to excellent fluorescence performance. Currently, porous organic polymer materials have attracted the interest of many researchers, and various sensors for uranyl ions have been developed based on photoinduced electron transfer (PET) and fluorescence resonance energy transfer (FRET) mechanisms. However, most porous organic polymer materials require high temperature, high pressure, and an oxygen-free environment, and are basically "Turn-off" type fluorescent probes, which limits the practical application of porous organic polymer materials.Therefore, it is necessary to develop a room-temperature-synthesized "Turn-On" fluorescent polymer for the detection of uranyl ions. SUMMARY

[0005] In order to overcome the above-mentioned deficiencies of the prior art, the present application provides a Turn-On fluorescent polymer having a fluorescence enhancement response to uranyl ions, and the fluorescent polymer can be synthesized at room temperature and is more suitable for industrial scale production applications.

[0006] In order to achieve the above-mentioned purposes, the technical scheme adopted by the present application is:

[0007] The first aspect of the present application provides a Turn-On fluorescent polymer, which has the following structure:

[0008]

[0009] The second aspect of the present application provides a preparation method of the Turn-On fluorescent polymer of the first aspect, specifically: mixing tetraphenyl ethylene tetraaldehyde and 3,3-dihydroxydiphenyl diamine, then adding 1,4-dioxane, benzyl alcohol, mesitylene and acetic acid solution, fully dissolving, degassing under vacuum and sealing, then incubating in an incubator for more than 3 days, and finally collecting the yellow solid product.

[0010] Preferably, the molar ratio of the tetraphenyl ethylene tetraaldehyde and 3,3-dihydroxydiphenyl diamine is 1:1-3.

[0011] Preferably, the concentration of the acetic acid solution is 5-7M.

[0012] Preferably, the volume ratio of the 1,4-dioxane, benzyl alcohol, mesitylene and acetic acid solution is 700-900:700-900:1315-1355:150-250.

[0013] Preferably, the degassing under vacuum is by rapid freezing through a liquid nitrogen bath, and then degassing through a freeze-pump-thaw cycle.

[0014] Preferably, collecting the yellow solid product specifically includes: after filtering the yellow solid product, washing with tetrahydrofuran and ethanol respectively, then filtering and collecting the yellow solid, and drying.

[0015] The third aspect of the present application provides the application of the Turn-On fluorescent polymer of the first aspect in the detection of uranyl ions.

[0016] Preferably, the method for detecting uranyl ions is specifically: preparing a stock solution of 0.01-0.05 mg / mL by dispersing the Turn-On type fluorescent polymer of the first aspect in a solvent, adding a to-be-detected solution containing uranyl ions (UO2 2+ ) to the stock solution at a volume ratio of 8-10:1, standing for more than 30 min, then measuring the fluorescence emission spectrum under an excitation wavelength of 314 nm, and finally obtaining the uranyl ion concentration of the to-be-detected solution according to the linear response curve between the fluorescence intensity at 401 nm and the uranyl ion concentration.

[0017] More preferably, the solvent is a mixed solvent of dimethylacetamide (DMAC) / H2O = 9:1.

[0018] More preferably, the stock solution further contains EDTA. 3+ and Cu 2+ can strongly interfere with the fluorescence intensity of TPE-COPs to uranyl ions, and EDTA can mask Fe 3+ and Cu 2+ , thereby not interfering with the response of TPE-COPs to UO2 2+ .

[0019] More preferably, the detection limit of uranyl ions is 30.6 nM.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] The present application ingeniously utilizes the structural characteristics of tetraphenylethylene tetracarboxaldehyde to synthesize an organic porous polymer having a fluorescence enhancement response to uranyl ions at room temperature, which not only expands the detection mode of uranyl ions, but also reduces energy consumption in synthesis, and enriches the detection mode of UO2 2+ . Overall, the present application has the following advantages:

[0022] (1) The fluorescent polymer TPE-COPs synthesized by the present application is a "Turn-On" type fluorescent polymer, which has high sensitivity, high selectivity and rapid response in detecting uranyl ions, can simultaneously improve sensitivity and anti-interference ability, realizes all-round consideration of detection limit, detection range and selectivity, and can be used for detecting trace uranyl ions, and has great application potential and value in biomedical research and rapid visual detection of environmental samples.

[0023] (2) The synthesis of the fluorescent polymer TPE-COPs of the present application can be completed at room temperature, and the process is simple, without the need for harsh environments such as high temperature, high pressure and anaerobic environment, and is more suitable for industrial scale production application. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1PXRD patterns of TPE-COPs (zoom-in of PXRD spectra of TPE-COPs);

[0025] Figure 2 PXRD patterns of TPE-COPs (zoom-in of PXRD spectra of TPE-COPs);

[0026] Figure 3 Fluorescence intensity of TPE-COPs vs. UO2 2+ concentration;

[0027] Figure 4 Excitation and emission spectra of TPE-COPs in DMAC solution (a) and in DMAC / H2O solution (b);

[0028] Figure 5 Fluorescence response of TPE-COPs to UO2 2+ in different solvents (a) and the change of fluorescence intensity when the water content in mixed solvent DMAC / H2O changes from 90% to 10% (b);

[0029] Figure 6 Effect of pH on the fluorescence enhancement signal of TPE-COPs to UO2 2+ ;

[0030] Figure 7 Effect of contact time on the fluorescence enhancement signal of TPE-COPs to UO2 2+ ;

[0031] Figure 8 Fluorescence stability of TPE-COPs when interacting with UO2 2+ ;

[0032] Figure 9 Effect of anions (a) and metal cations (b) on the response signal of TPE-COPs;

[0033] Figure 10 Change of response of TPE-COPs to UO2 2+ (5 μΜ) under the interference of metal cations (500 μΜ) (a) and anions (500 μΜ) (b);

[0034] Figure 11 Interference of Fe 3+ (a) and Cu 2+ (b) on the fluorescence signal of TPE-COPs to UO2 2+ and masking;

[0035] Figure 12 Fluorescence response of TPE-COPs to UO2 2+The emission spectrum (a) and the fluorescence intensity of TPE-COPs versus UO2 2+ The linear fitting curve of the concentration (b). DETAILED DESCRIPTION

[0036] The specific embodiments of the present application are further described below. It should be noted that the description of these embodiments is intended for purposes of illustration only and is not intended to be limiting. Furthermore, the technical features involved in each of the embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0037] The experimental methods used in the following examples are all conventional methods unless otherwise specified. The experimental materials used in the following examples are all commercially available unless otherwise specified.

[0038] Example 1: Synthesis of Covalent Organic Polymers (TPE-COPs)

[0039] 1. Tetraphenylethene tetraaldehyde (17.8 mg, 40 μmol) and 3,3-dihydroxybiphenyl diamine (17.3 mg, 80 μmol) were added into a 10 mL heat-resistant glass tube, and then 1,4-dioxane (800 μL), benzyl alcohol (800 μL), mesitylene (1335 μL) and acetic acid (AcOH) solution (200 μL, 6 M) were added into the mixture. After the mixture was dissolved by ultrasonic, the glass tube was rapidly frozen by liquid nitrogen bath, and then degassed and sealed by three cycles of freezing-vacuum degassing-thawing (the glass tube was rapidly frozen by liquid nitrogen bath, then degassed by vacuum pump, and then the above operation was repeated after the solution was dissolved, and the operation was repeated for three times). After that, the glass tube was placed in a safe location of the greenhouse for 3 d, and then the yellow target was obtained. After that, the yellow solid was filtered, washed with tetrahydrofuran (THF 3 x 20 mL), anhydrous ethanol (3 x 20 mL) for three times, and then the yellow solid was collected by filtration and dried at 70 °C under vacuum for 12 h to obtain the TPE-COPs. The specific preparation process is shown in Figure 1 .

[0040] The crystalline structure of TPE-COPs was detected by X-ray powder diffraction experiment (PXRD). As can be seen from the PXRD spectrum, tetraphenylethene tetraaldehyde ( Figure 2 red line) and 3,3-dihydroxybiphenyl diamine ( Figure 2 blue line) have typical crystal structures. TPE-COPs ( Figure 2 black line) has a strong broad peak at 20-30°, indicating that the material is an amorphous polymer.

[0041] 2、Considering that the polarity of the solvent, the concentration of the catalyst, and the reaction time will have a certain influence on the performance of COPs, different solvents and catalysts are used to synthesize the same COPs in this experiment, and their performance is explored. See Table 1 for details. The specific synthesis method is as follows:

[0042] Take several 15 mL centrifuge tubes, respectively add tetraaldehyde tetraphenyl ethylene (17.8 mg, 40 μmol) and 3,3-dihydroxydiphenyl diamine (17.3 mg, 80 μmol), and add about 3 mL of different solvents and catalysts to each centrifuge tube, respectively, and then add 0.3 mL (6M or 12M) of HAC. After ultrasonic mixing, the mixture is quickly frozen by liquid nitrogen bath, degassed by three cycles of freezing-vacuumizing-thawing and sealed, and then placed at room temperature for 3 or 5 days. After the appearance of yellow target, filter the yellow solid, and wash it with tetrahydrofuran (THF 3x20 mL), anhydrous ethanol (3x20 mL) each for three times, and finally collect the yellow solid by filtration and place it in a vacuum dryer at 70°C for 12h.

[0043] From Figure 3 It can be seen that TPE-COPs have high sensitivity to UO2 2+ , especially the TPE-COPs synthesized under the conditions of 1,4-dioxane (800 μL), benzyl alcohol (800 μL), mesitylene (1335 μL) and acetic acid solution (200 μL, 6M) have good linear relationship (TPE-COPs detection method for uranyl ion, see Example 2 for details) and the lowest detection limit is 0.0306 μΜ (7.283 ng / L). Therefore, COPs synthesized under this condition are used for performance exploration in the subsequent experiment. 2+

[0044] Table 1 Synthesis conditions of TPE-COPs

[0045]

[0046]

[0047] Example 2: TPE-COPs for detecting uranyl ions and optimization of detection conditions

[0048] 1、Optimal fluorescence emission spectrum of TPE-COP

[0049] ​Take 5 mg of TPE-COPs dispersed in 200 mL of nitrogen dimethylacetamide to prepare a 0.025 mg / mL TPE-COPs stock solution. Then take several 1.5 mL centrifuge tubes, add 1000 μL of the stock solution to one group, add 900 μL of the stock solution to another group, and add 100 μL of 50 μM uranium ions to it, shake well after standing for 30 min. From Figure 4 It can be seen that the emission peak of pure TPE-COPs is at 384 nm, and when UO2 2+ The latter emission peak will be red shifted to 401 nm, and the corresponding excitation is 314 nm, so the subsequent measurements are all at an excitation wavelength of 314 nm.

[0050] 2, solvent optimization

[0051] In order to explore the fluorescence intensity of TPE-COPs in different solvents, this experiment selected the commonly used solvents in the laboratory, such as ethanol, tetrahydrofuran, nitrogen dimethylacetamide (DMAC) and DMAC / H2O mixed solvents with a volume fraction (fw water) of 90% to 10% as the solvent of the fluorescent sensor, and explored the fluorescence intensity change of TPE-COPs solution (0.025 mg / mL) itself and after adding 5 μM UO2 2+ Figure 5 a It can be seen that the fluorescence intensity of COPs dispersed in different solvents is significantly different, and the fluorescence intensity of COPs dispersed in DMAC / H2O=9:1 is the strongest. COPs dispersed in water has almost no fluorescence, and there is no change in fluorescence intensity after adding uranium ions, which may be because the hydrophobicity of COPs is too strong, after adding DMAC, COPs can be well dispersed in the mixed solution of DMAC and water, and the polarity of the solution becomes smaller, and the fluorescence intensity becomes stronger. And from Figure 5 b It can be seen that the smaller the proportion of water in the mixed solution, the fluorescence intensity gradually increases. It may be because the content of water gradually decreases, and the intermolecular hydrogen bond interaction will be weakened. Therefore, the fluorescence intensity of COPs is the strongest in DMAC / H2O=9:1, so the subsequent experiments are all carried out under this condition.

[0052] 3, pH

[0053] ​In aqueous solutions, the degree of protonation at the binding sites of materials and guest molecules is affected by the solution pH. To investigate the effect of the pH of a mixed solvent (v / v, DMAC / H2O) on TPE-COPs, two sets of comparative experiments were designed. One set used 0.1M Tris-HCl as a buffer solution to prepare uranium solutions (100 μL 50 μM) with pH values ​​of 1, 2, 3, 4, 5, 6, 7, 8, and 9. The other set used aqueous solutions with pH values ​​of 1, 2, 3, 4, 5, 6, 7, 8, and 9 mixed with DMAC to obtain background solutions. The effects of adding UO2 on TPE-COPs (0.025 mg / mL) were investigated. 2+ The fluorescence change afterward. Considering that solution pH is a key factor determining the types of uranium present in the solution and the detection capability, the optimal pH range of 1–10 was sought to obtain the best response performance for uranium. Figure 6 It can be seen that the material's uranium detection performance is highly pH dependent, and the fluorescence enhancement effect caused by uranium is most obvious when the pH is between 3 and 5.

[0054] 4. Optimal contact time

[0055] like Figure 7 As shown, TPE-COPs (0.025 mg / mL) and UO2 2+ The response can reach equilibrium within 30 minutes at 5 μM O2. 2+ At the specified concentration, the fluorescence intensity increased by 2.6 times compared to the blank within 1 minute, and after reaching equilibrium at 30 minutes, the fluorescence intensity increased by 13 times compared to the blank. Therefore, it can achieve the purpose of rapid detection of polluted water bodies in the environment.

[0056] 5. Investigation of fluorescence stability

[0057] Disperse 5 mg of TPE-COPs in 200 mL of L-MAC to prepare a 0.025 mg / mL TPE-COPs stock solution. Then, transfer 900 μL of the TPE-COPs stock solution to a 1.5 mL centrifuge tube and add 100 μL of 50 μM UO2. 2+ Then, the fluorescence changes were detected using an FL-2700 fluorescence spectrometer. Figure 8 It can be seen that TPE-COPs have good fluorescence stability, with little change in fluorescence intensity over two hours, which can serve as a basis for subsequent TPE-COPs detection of UO2. 2+ Provide favorable conditions.

[0058] 6. Selectivity

[0059] Take 5 mg of TPE-COPs and disperse them in 200 mL of DMAC to prepare a TPE-COPs stock solution of 0.025 mg / mL. Then take several 1.5 mL centrifuge tubes, add 900 μL of the stock solution to each, and add 100 μL of different metal ions (UO2 2+ , Ni + , Co 2+ , Pb 2+ , Zn 2+ , Cu 2+ , Na + , Mg 2+ , Tb 3+ , Eu 3+ , Fe 3+ , Co 2+ , K + , Ca 2+ , Mg 2+ , Ag + , Cs + ) to each, except that the concentration of UO2 2 + is 50 μM and the concentration of the other metal ions is 500 μM. The metal ion solution is prepared from the corresponding nitrate salt and the anion solution is prepared from the corresponding sodium salt. A sample without any metal ions is also prepared as a blank sample. After thorough mixing, the fluorescence emission spectrum of the solution is measured using an FL-2700. It can be seen from Figure 9 that TPE-COPs has good selectivity for UO2 2+ .

[0060] 7. Anti-interference property

[0061] (1) Metal ions

[0062] Take 5 mg of TPE-COPs and disperse them in 200 mL of DMAC to prepare a TPE-COPs stock solution of 0.025 mg / mL. Then take several 1.5 mL centrifuge tubes, add 900 μL of the stock solution to each, and add 100 μL of different metal ions (UO2 2+ and 50 μL of 1000 μM of each metal ion), and a sample without any metal interference ions is also prepared as a blank sample. After standing for 30 min, the prepared sample is shaken and the fluorescence emission spectrum is measured using an FL-2700.

[0063] (2) Anions

[0064] Disperse 5 mg of TPE-COP in 200 mL of L-MAC to prepare a 0.025 mg / mL TPE-COPs stock solution. Take several 1.5 mL centrifuge tubes, add 900 μL of the stock solution to each tube, and then add 100 μL of ion exchange solution (50 μL of 100 μM UO2). 2 + A blank sample was prepared simultaneously with 50 μL of 10000 μM anion (and 50 μL of 10000 μM anion). After standing for 30 min, the prepared sample was shaken well and fluorescence emission spectroscopy was performed using an FL-2700.

[0065] (3) Masking experiment

[0066] from Figure 10 It can be seen that Fe 3+ and Cu 2+ It would strongly interfere with the fluorescence intensity of TPE-COPs for uranyl ions, therefore, an equal amount of EDTA was chosen to target Fe. 3+ and Cu 2+ To perform masking (Fe 3+ and Cu 2+ Equal amounts of Fe 3+ and Cu 2+ The final concentration was 50 μM. Figure 11 It can be seen that EDTA can successfully mask Fe. 3+ and Cu 2+ Interference with TPE-COPs on UO2 2+ The response.

[0067] 8. Quantitative analysis

[0068] To investigate the effect of TPE-COPs on UO2 2+ The detection sensitivity, in different UO2 2+ The fluorescence spectra of TPE-COPs were tested at various concentrations.

[0069] The fluorescence intensity of TPE-COPs varies with UO2 2+ The concentration increases with increasing concentration, and the UO2 concentration at 6 μM increases. 2+ The fluorescence intensity was increased by 10.9 times compared to the blank. Figure 12 The fluorescence intensity of TPE-COPs at 401 nm was shown to be related to UO2. 2+ The linear response curves for concentrations (0.1-6 μM) showed a correlation coefficient of 0.997. TPE-COPs to UO2 2+ The detection limit was 30.6 nM (approximately 7.238 ng / L), which is lower than the World Health Organization's limit for UO2 in drinking water. 2+ The pollution limit (30 ng / L) proves that TPE-COPs can be used for UO2.2+ high sensitivity detection.

[0070] In addition, from the results of Figure 3 and Figure 12 It can be seen that the fluorescence intensity of the TPE-COPs increases with the increase of the concentration of uranyl ions, and shows a good linear relationship in the range of 0-6 μM of UO2 2+ . It shows that the covalent organic polymer TPE-COPs of the present application belongs to the Turn-On type fluorescent polymer.

[0071] 9. Determination of actual water samples

[0072] The applicability of TPE-COPs in detecting UO2 2+ in actual water samples was evaluated, and the accuracy of the measurement was verified by the standard addition recovery method. Among them, the volume of the water sample was 100 μL. As shown in Table 2, using TPE-COPs can achieve high recovery rates of uranium in the Pearl River water and radium residue ore water samples, respectively, with recovery rates as high as 99.7%-102.5% and 102.3%-105%, respectively, and the relative standard deviation (RSD) is 4%-6.5% and 2.1%-4.2%, respectively. The above results show that the new TPE-COPs have good accuracy, and are expected to be reliably applied to rapid on-site detection of UO2 2+ in actual water samples.

[0073] Table 2 Determination results of UO2 2+ in the Pearl River water and radium residue ore water samples using TPE-COPs

[0074]

[0075] * The initial concentration of UO2 2+ in the sample was determined by ICP-MS method.

[0076] The above describes the embodiments of the present application in detail, but the present application is not limited to the described embodiments. For those skilled in the art, various changes, modifications, replacements and variations of these embodiments can be made without departing from the principles and spirits of the present application, and still fall within the protection scope of the present application.

Claims

1. A method for preparing a Turn-On fluorescent polymer, characterized by, tetraphenyl ethylene tetracarboxylic aldehyde and 3,3-dihydroxydiphenyl diamine are mixed, 1,4-dioxane, benzyl alcohol, mesitylene and acetic acid solution are added, after fully dissolving, degassing under vacuum and sealing, then incubate in the dark for 3 days or more, finally collect the yellow solid product; the molar ratio of tetraphenyl ethylene tetracarboxylic aldehyde and 3,3-dihydroxydiphenyl diamine is 1:1-3, the concentration of acetic acid solution is 5-7 M, the volume ratio of 1,4-dioxane, benzyl alcohol, mesitylene and acetic acid solution is 700-900:700-900:1315-1355:150-250.

2. The Turn-On fluorescent polymer prepared by the preparation method of claim 1.

3. The use of the Turn-On fluorescent polymer of claim 2 in detecting uranyl ions.

4. Use according to claim 3, characterized in that, The method for detecting uranyl ions is as follows: the Turn-On fluorescent polymer of claim 2 is dispersed in a solvent to prepare a stock solution with a concentration of 0.01-0.05 mg / mL, then 8-10:1 volume ratio of the stock solution and the solution to be tested containing uranyl ions is added, after standing for 30 min or more, the fluorescence emission spectrum is measured under the excitation wavelength of 314 nm, finally according to the linear response curve of the fluorescence intensity at 401 nm and the concentration of uranyl ions, the concentration of uranyl ions in the solution to be tested is obtained.

5. Use according to claim 4, characterized in that, The solvent is a mixed solvent of DMAC / H2O=9:

1.

6. Use according to claim 4, characterized in that, The stock solution also contains EDTA.

7. Use according to claim 4, characterized in that, The detection limit of uranyl ions is 30.6 nM.

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