Fluorescence analysis method

Abstract

The invention belongs to the technical field of fluorescence sensing, and particularly relates to a fluorescence analysis method which comprises the following steps: mixing a solution to be detected with chromium selenide quantum dots, and detecting the fluorescence intensity of a system to obtain the content of sodium tripolyphosphate in the solution to be detected. According to the present invention, it is found that sodium tripolyphosphate can selectively quench the fluorescence of chromium selenide quantum dots, such that the chromium selenide quantum dot-based sodium tripolyphosphate fluorescence analysis method is provided so as to meet the requirement of efficient detection of sodium tripolyphosphate.

Description

Technical Field

[0001] This invention belongs to the field of fluorescence sensing technology, and specifically relates to a fluorescence analysis method. Background Technology

[0002] Sodium tripolyphosphate (STPP) is primarily used as a food additive (moisture retainer, quality improver), and also has applications in the detergent and ceramics industries. The detection of STPP content is crucial. When used as a food additive, excessive intake may interfere with the absorption of minerals such as calcium and magnesium, and long-term excessive intake may lead to osteoporosis or kidney strain. Detecting STPP content ensures that its concentration in food meets national standards. Furthermore, wastewater containing STPP can promote excessive algae growth and deplete oxygen in the water. Detection of STPP in wastewater discharged by relevant production enterprises helps monitor the effectiveness of industrial wastewater treatment and prevent ecological damage.

[0003] Currently, common methods for detecting sodium tripolyphosphate include spectrophotometry (ammonium molybdate method), ion chromatography (IC), titration, high-performance liquid chromatography (HPLC), and inductively coupled plasma optical emission spectrometry (ICP-OES). However, these methods have certain limitations in practical applications, such as complex operation, long detection time, insufficient accuracy, expensive equipment, and susceptibility to interference. These shortcomings not only increase detection costs but may also lead to deviations in test results, thereby affecting product quality control and production process optimization.

[0004] Uranium is widely distributed in various environments, including uranium mines, seawater, rivers, soil, and even living organisms. As a primary raw material for generating electricity with minimal greenhouse gas emissions, uranium has been used in various military and civilian sectors. With the increasing proportion of nuclear power and the rapid development of the nuclear industry, nuclear energy production and nuclear waste disposal have attracted more attention. Although uranium has many oxidation states (+2, +3, +4, +5, and +6), it typically exists as a stable uranyl ion (UO2). 2 + It exists in the form of UO2. 2+ It is the most stable and has the best solubility in water. It can enter the ground or surface water system through ecological cycle. However, the chemical toxicity and radioactivity of uranyl often cause irreversible damage to organs such as the kidneys and brain of organisms, and further lead to disorders of the digestive, immune, hematopoietic and reproductive systems in the body.

[0005] The residual uranyl ions in the environment are mostly in trace quantities, and the test solutions are complex, containing a large number of interfering substances, which poses difficulties and challenges to the accurate determination of uranyl ion residues. Conventional detection methods, such as spectrophotometry, electron-coupled plasma mass spectrometry, and high-performance liquid chromatography, may have shortcomings such as high detection costs, complex operation requiring professional personnel, high instrument requirements, and inability to perform rapid real-time detection. In recent years, fluorescence analysis, as a novel analytical technique, has become an indispensable analytical technique due to its advantages such as simplicity, good selectivity, high sensitivity, fast response, and real-time monitoring.

[0006] Currently, the fluorescence analysis methods reported in the literature are based on fluorescent materials such as cadmium sulfide quantum dots, cadmium telluride quantum dots, and lanthanide metal-organic frameworks. However, most of these methods are based on UO2. 2+ Single-emission fluorescence analysis, which causes fluorescence quenching in fluorescent materials, is susceptible to photobleaching of fluorophores, light scattering caused by the sample matrix, fluctuations in the excitation source, changes in the local concentration of the probe, and the influence of the microenvironment surrounding the probe. UO2 2+ The autofluorescence is very weak, making it difficult to achieve trace levels of UO2 using autofluorescence. 2+ For the detection of UO2, a sensitizer needs to be added to increase its intensity. 2+ Autofluorescence, thus achieving UO2 2+ Sensitive detection.

[0007] Ratiometric fluorescence systems refer to systems where the fluorescence intensity at two different wavelengths changes with the analyte concentration, and the ratio of these two wavelengths enables the detection of the analyte. By establishing an internal standard, ratiometric fluorescence systems possess self-regulating capabilities, significantly reducing interference from instrumental and environmental factors, exhibiting higher sensitivity and accuracy, and are more suitable for practical applications. Therefore, constructing a UO2-based system... 2+ Ratio-modulated fluorescence analysis of autofluorescence is of great significance. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide a fluorescence analysis method.

[0009] In a first aspect, the present invention provides a fluorescence analysis method for sodium tripolyphosphate based on chromium selenide quantum dots. The detection method includes the following steps: mixing the test solution with chromium selenide quantum dots, and obtaining the content of sodium tripolyphosphate in the test solution by detecting the fluorescence intensity of the system.

[0010] Among them, chromium selenide quantum dots are synthesized by hydrothermal method using chromium salt precursor, sodium selenose sulfate precursor and stabilizer.

[0011] Preferably, the chromium salt precursor is one or more of chromium acetate, chromium chloride, chromium nitrate, and chromium sulfate.

[0012] Preferably, the preparation process of the sodium selenosulfate precursor includes the following steps: mixing sodium sulfite solution and selenium powder, and then refluxing to obtain sodium selenosulfate.

[0013] Preferably, the stabilizer is one or more of thioglycolic acid, 3-mercaptopropionic acid, 4-mercaptobutyric acid, 5-mercaptovalerate, and 6-mercaptohexanoic acid.

[0014] Preferably, the preparation process of the chromium selenide quantum dots includes the following steps: heating the chromium salt precursor solution to reflux in an inert environment, then adding a stabilizer solution and an alkaline solution, refluxing the reaction, then adding a selenium salt precursor solution, refluxing the reaction to obtain chromium selenide quantum dots.

[0015] Preferably, the method includes the following steps: adding a buffer solution to a centrifuge tube, then adding chromium selenide quantum dots, vortexing and mixing, adding the test solution, reacting at room temperature for a certain time, and then testing the fluorescence spectrum of the system in the range of 360–850 nm at an excitation wavelength of 350 nm and an emission wavelength of 680 nm. The fluorescence quenching efficiency of chromium selenide quantum dots [(F0-F) / F0] is linearly related to the concentration of sodium tripolyphosphate.

[0016] Preferably, the ratio of the volume of the buffer solution to the volume of the chromium selenide quantum dots to the volume of the test solution is 890-800:10-100:100.

[0017] Preferably, the buffer solution is composed of an acetate-sodium acetate and Tris-HCl buffer system, and the pH of the buffer solution is 3 to 10.

[0018] Preferably, the reaction time is 1 to 30 minutes.

[0019] This invention discovers that sodium tripolyphosphate can quench the fluorescence of chromium selenide quantum dots. Based on this discovery, a fluorescence analysis method for sodium tripolyphosphate based on chromium selenide quantum dots is provided to meet the need for efficient detection of sodium tripolyphosphate.

[0020] A second aspect of the present invention provides a ratiometric fluorescence sensing detection system for uranyl ions, comprising sulfur quantum dots and sodium tripolyphosphate.

[0021] Preferably, the preparation process of the sulfur quantum dots includes the following steps: sublimed sulfur is placed in a container, and then polyethylene glycol-400 and deionized water are added sequentially. Under stirring, sodium hydroxide solution is slowly added dropwise. After the sublimed sulfur is completely dissolved, the reaction is carried out at a constant temperature of 60-80°C for 60-84 hours. After cooling to room temperature, the resulting reaction solution is transferred to a dialysis bag with a molecular weight cutoff of 3500 Da for dialysis to obtain sulfur quantum dots.

[0022] Preferably, the ratio of the volume of the sulfur quantum dots, the volume of the sodium tripolyphosphate solution, and the total volume of the detection system is 20-100:100:1000; and the concentration of sodium tripolyphosphate in the sodium tripolyphosphate solution is 50-200 mM.

[0023] Uranyl ions can be detected using the ratiometric fluorescence sensing detection system for uranyl ions as described above. Specifically, the method includes the following steps: in a buffer solution, sulfur quantum dots, sodium tripolyphosphate and the test solution are mixed and reacted.

[0024] Preferably, the buffer solution is an acetate-sodium acetate buffer solution with a pH of 2.6 to 7.6.

[0025] Preferably, the reaction time after mixing is 3 to 20 minutes.

[0026] Preferably, after the reaction is completed, under an excitation wavelength of 300 nm and an emission wavelength of 500 nm, the fluorescence peak in the test system in the range of 370–650 nm is measured. The ratio of the fluorescence enhancement value at 520 nm to the fluorescence intensity at 440 nm is linearly related to the concentration of uranyl ions.

[0027] The ratiometric fluorescence sensing detection system provided by this invention uses sulfur quantum dots as a reference fluorescent probe and sodium tripolyphosphate as a UO2 recognition material. 2+ and enhance UO2 2+ An auxiliary medium with autofluorescence can be used to achieve the control of UO2. 2+ The quantitative detection method has high sensitivity and selectivity, thus enabling the detection of residual UO2 in aquatic environments and food. 2+ The detection.

[0028] A third aspect of the present invention provides a phosphate-assisted uranyl ion ratio-based fluorescence detection method, the detection method comprising the following steps: mixing fluorescent quantum dots and a phosphate anion solution, then adding the solution to be tested, and after the reaction, obtaining the content of uranyl ions in the solution to be tested by measuring the fluorescence intensity of the test system; wherein the fluorescent quantum dots are chromium selenide quantum dots or zinc sulfide quantum dots.

[0029] Preferably, the detection method includes the following steps: adding a buffer solution to a centrifuge tube, then adding the fluorescent quantum dots, vortexing and mixing, adding a phosphate anion solution, vortexing and mixing, then adding the test solution, reacting at room temperature for a certain time, and then testing the fluorescence spectrum.

[0030] Preferably, the fluorescent quantum dots are chromium selenide quantum dots. The fluorescence spectrum of the system was measured in the range of 360–850 nm at an excitation wavelength of 300 nm and an emission wavelength of 680 nm. 520 / F 680It has a linear relationship with the concentration of uranyl ions.

[0031] Preferably, the fluorescent quantum dots are zinc sulfide quantum dots. The fluorescence spectrum of the system is measured in the range of 350–650 nm at an excitation wavelength of 300 nm and an emission wavelength of 600 nm. 520 / F 600 It has a linear relationship with the concentration of uranyl ions.

[0032] Preferably, the phosphate anion is one or more of sodium phosphate, sodium pyrophosphate, sodium tripolyphosphate, and sodium hexametaphosphate.

[0033] Preferably, the concentration of phosphate anions in the phosphate anion solution is 10–350 mM.

[0034] The buffer solution is an acetate-sodium acetate buffer solution with a pH of 2.6–7.6 and a reaction time of 1–30 min.

[0035] Preferably, the preparation process of the chromium selenide quantum dots includes the following steps: (1) Preparation of sodium selenosulfate precursor solution: Take deionized water that has been deoxygenated by purging with nitrogen into a container, keep it in an inert environment, heat the deionized water to 70-90°C under stirring conditions, then add sodium sulfite solution dropwise into the above deionized water, stir and mix well, finally add selenium powder into the above mixed solution, stir, and reflux to obtain sodium selenosulfate precursor solution; (2) Synthesis of chromium selenide quantum dots: Under stirring conditions, the chromium salt precursor solution was slowly added dropwise to a deionized aqueous solution that had been purged with nitrogen to remove oxygen. The inert environment was maintained and the solution was heated to reflux. Then, the stabilizer solution was added to the above mixed solution and mixed well. After that, the alkali solution was slowly added dropwise to the mixed solution until the solution just turned colorless. The reflux reaction was continued. The sodium selenosulfate precursor solution was added dropwise to the mixed solution and the reflux reaction was continued to obtain chromium selenide quantum dots.

[0036] Preferably, the preparation process of the zinc sulfide quantum dots includes the following steps: under stirring conditions, zinc sulfate solution and manganese chloride solution are added to the solution in sequence, and nitrogen gas is passed through to remove dissolved oxygen; then, sodium sulfide nonahydrate solution is dissolved in deionized water that has been pre-purged with nitrogen to remove oxygen, and the sodium sulfide solution is slowly added dropwise to the above mixed solution, stirring is continued, and an ethanol solution containing (3-mercaptopropyl)triethoxysilane is slowly added dropwise to the mixed solution, and the reaction continues to obtain zinc sulfide quantum dots.

[0037] This invention is based on UO2 2+ It can quench the fluorescence of chromium selenide quantum dots and zinc sulfide quantum dots, and sodium tripolyphosphate can be used as a UO2 recognizer. 2+ and enhance UO2 2+Based on the above findings, this invention constructs a ratiometric fluorescence analysis method assisted by sodium tripolyphosphate, which can achieve the analysis of UO2. 2+ It features sensitive detection, fast response, wide linear range, low detection limit, and simple operation, and can be used for the detection of UO2 residues in aquatic environments and food. 2+ Sensitive detection. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0039] Figure 1 For process analysis using fluorescence analysis based on chromium selenide quantum dots and zinc sulfide quantum dots; Figure 2 The effect of chromium selenide quantum dot volume on the sensitivity of sodium tripolyphosphate detection system; Figure 3 The effect of buffer solution pH on the sensitivity of sodium tripolyphosphate detection system; Figure 4 The effect of system reaction time on the sodium tripolyphosphate detection system; Figure 5 Diagram showing interference from potentially coexisting substances; Figure 6 The fluorescence response diagrams are shown for different concentrations of sodium tripolyphosphate based on the fluorescence analysis of chromium selenide quantum dots. Figure 7 The linear relationship between quenching efficiency [(F0-F) / F0] and sodium tripolyphosphate concentration is shown for different concentrations of sodium tripolyphosphate.

[0040] Figure 8 , three The effect of sodium polyphosphate concentration on the sensitivity of the detection system; Figure 9 The effect of sulfur quantum dot volume on the sensitivity of the detection system; Figure 10 The effect of buffer solution pH on the sensitivity of the detection system; Figure 11 System reaction time diagram; Figure 12 Fluorescence response diagrams of sodium tripolyphosphate-assisted sulfur quantum dot-based ratiometric fluorescence analysis at different concentrations of UO22+; Figure 13The linear relationship between F520 / F440 and UO22+ at different concentrations of UO22+; Figure 14 Interference diagrams for the detection of other metal ions when detecting UO22+: a: UO22+; b: Al3+; c: Ag+; d: Mn2+; e: Cu2+; f: Eu3+; g: Fe2+; h: Fe3+; i: Mg2+; j: Ce3+; k: Na+; l: Ni2+.

[0041] Figure 15 Process analysis based on fluorescence analysis of chromium selenide quantum dots; Figure 16 Process analysis based on fluorescence analysis of zinc sulfide quantum dots; Figure 17 The effect of chromium selenide quantum dot volume on the sensitivity of the UO22+ detection system based on chromium selenide quantum dots; Figure 18 , three Sodium polyphosphate concentration on UO2 based on chromium selenide quantum dots 2+ The influence of the sensitivity of the detection system; Figure 19 The effect of buffer solution pH on UO2 based on chromium selenide quantum dots 2+ The influence of the sensitivity of the detection system; Figure 20 The effect of system reaction time on the sensitivity of the UO22+ detection system based on chromium selenide quantum dots; Figure 21 Fluorescence response diagrams of sodium tripolyphosphate-assisted ratiometric fluorescence analysis based on chromium selenide quantum dots at different concentrations of UO22+; Figure 22 The linear relationship between F520 / F680 and UO22+ under different concentrations of UO22+ in a detection system based on chromium selenide quantum dots; Figure 23 Detection of UO2 using a chromium selenide quantum dot-based detection system 2+ Interference diagram for other metal ion detection, a: UO2 2+ (10 μM), b: Ag + , c: Ce 3+ , d: Al 3+ , e: Fe 3+ f: Fe 2+ , g: Eu 3+ , h: Ni 2+ i: Mg 2+ , j: Mn 2+ ; k: Na + (20 μM); Figure 24 The effect of zinc sulfide quantum dot volume on the sensitivity of the UO22+ detection system based on zinc sulfide quantum dots; Figure 25 , three Sodium polyphosphate concentration on UO2 based on zinc sulfide quantum dots 2+ The influence of the sensitivity of the detection system; Figure 26 The effect of buffer solution pH on UO2 based on zinc sulfide quantum dots 2+ The influence of the sensitivity of the detection system; Figure 27 The effect of system reaction time on the sensitivity of the UO22+ detection system based on zinc sulfide quantum dots; Figure 28 Fluorescence response diagrams of sodium tripolyphosphate-assisted ratiometric fluorescence analysis based on zinc sulfide quantum dots at different concentrations of UO22+; Figure 29 In a detection system based on zinc sulfide quantum dots, the linear relationship between F520 / F600 and UO22+ at different concentrations of UO22+; Figure 30 Detection of UO2 using a zinc sulfide quantum dot-based detection system 2+ Interference diagram for other metal ion detection, a: UO2 2+ (10 μM), b: Ce 3+ , c: Al 3+ , d: Fe 3+ , e: Fe 2+ f: Eu 3+ , g: Ni 2+ h: Mg 2+ ,i: Mn 2+ , j: Na + (20 μM); Volume-to-volume ratio of UO2 based on chromium selenide quantum dots 2+ The impact of the sensitivity of the detection system. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0043] Example 1: Preparation of sodium selenosulfate precursor solution: 25 mL of nitrogen-purged deionized water was measured into a 50 mL round-bottom flask. Maintaining an inert environment, the nitrogen-purged deionized water was heated to 80°C with stirring. Then, 5 mL of 0.8 M sodium sulfite solution was added dropwise to the nitrogen-purged deionized water, and the mixture was stirred until homogeneous. Finally, 50 mg of selenium powder was added to the mixture, and the mixture was stirred and refluxed at 80°C for 5 hours.

[0044] Synthesis of chromium selenide quantum dots: Under stirring conditions, 10 mL of chromium acetate solution (70 mM) was slowly added dropwise to 180 mL of nitrogen-purged deionized water solution, maintaining an inert environment, and heated to 100°C under reflux. Then, 10 mL of thioglycolic acid solution (180 mM) was added to the above mixture and mixed thoroughly. Subsequently, sodium hydroxide solution (1 M) was slowly added dropwise to the mixture until the solution just turned colorless. After continuing reflux for 1 hour, 5 mL of sodium selenosulfate precursor solution was added dropwise to the mixture, and reflux was continued for 4 hours.

[0045] The detection procedure for sodium tripolyphosphate is as follows: Add acetate-sodium acetate buffer solution (pH=6) to a 1 mL centrifuge tube, then add 50 μL of the prepared chromium selenide quantum dots or zinc sulfide quantum dots, vortex mix, and then add 100 μL of sodium tripolyphosphate standard solution (concentration of 0 or 100 mM). The total volume of the system is 1 mL. After reacting at room temperature for 5 min, the fluorescence spectrum of the system in the range of 360–850 nm is tested at an excitation wavelength of 350 nm and an emission wavelength of 680 nm.

[0046] like Figure 1 As shown, sodium tripolyphosphate significantly quenches the fluorescence peak of chromium selenide quantum dots (CdSe QDs) at 480 nm, while having little effect on the fluorescence of zinc sulfide quantum dots (ZnS QDs). Therefore, chromium selenide quantum dots are more suitable for constructing fluorescence detection methods based on sodium tripolyphosphate.

[0047] Example 2: The chromium selenide quantum dots prepared in Example 1 were used for detection in this example.

[0048] The detection procedure for sodium tripolyphosphate is as follows: Add acetate-sodium acetate buffer solution (pH=5) to a 1 mL centrifuge tube, then add 10–100 μL of the prepared chromium selenide quantum dots, vortex mix, and then add 100 μL of sodium tripolyphosphate standard solution (concentration of 0 and 300 mM). The total volume of the system is 1 mL. After reacting at room temperature for 5 min, the fluorescence spectrum of the system in the range of 360–850 nm is tested at an excitation wavelength of 350 nm and an emission wavelength of 680 nm.

[0049] like Figure 2 As shown, the volume of added chromium selenide quantum dots significantly affects the sensitivity of the sodium tripolyphosphate detection system. 50 μL yields the best detection effect, while there is no significant difference between 20 μL and 50 μL. 100 μL results in slightly worse detection. Therefore, the volume of added chromium selenide quantum dots should not exceed 100 μL.

[0050] Example 3: The chromium selenide quantum dots prepared in Example 1 were used for detection in this example.

[0051] The detection procedure for sodium tripolyphosphate: Add 850 μL of a buffer solution (pH = 3–10) consisting of an acetate-sodium acetate and Tris-HCl buffer system with different pH values ​​to a 1 mL centrifuge tube, then add 50 μL of the prepared chromium selenide quantum dots, vortex mix, and then add 100 μL of sodium tripolyphosphate standard solution (concentration of 0 and 300 mM). The total volume of the system is 1 mL. After reacting at room temperature for 5 min, the fluorescence spectrum of the system in the range of 360–850 nm is tested at an excitation wavelength of 350 nm and an emission wavelength of 680 nm.

[0052] like Figure 3 As shown, the pH value of the buffer solution has a certain impact on the sensitivity of the sodium tripolyphosphate detection system, with the detection effect being optimal when the pH value of the buffer solution is 8.

[0053] Example 4: The chromium selenide quantum dots prepared in Example 1 were used for detection in this example.

[0054] The detection procedure for sodium tripolyphosphate: Add 850 μL of a buffer solution (pH=8) composed of a Tris-HCl buffer system to a 1 mL centrifuge tube, then add 50 μL of the prepared chromium selenide quantum dots, vortex mix, and then add 100 μL of sodium tripolyphosphate standard solution (concentration of 0 and 300 mM). The total volume of the system is 1 mL. After reacting at room temperature for different times (1–30 min), the fluorescence spectrum of the system in the range of 360–850 nm is tested at an excitation wavelength of 350 nm and an emission wavelength of 680 nm.

[0055] Figure 4 The figure shows the effect of system reaction time on the sodium tripolyphosphate detection system. The optimal detection effect can be basically achieved after 1 min of reaction. Longer reaction time has no significant impact on the detection effect, indicating that the detection method of the present invention can produce results very quickly.

[0056] Based on the above, the optimal reaction conditions can be determined as follows: chromium selenide quantum dots added in a volume of 50 μL, buffer solution pH of 8, and reaction time of 1 min.

[0057] Example 5: The chromium selenide quantum dots prepared in Example 1 were used for detection in this example.

[0058] Interference detection procedure for sodium tripolyphosphate: Add 850 μL of a buffer solution (pH=8) consisting of a Tris-HCl buffer system to a 1 mL centrifuge tube, then add 50 μL of the prepared chromium selenide quantum dots, vortex mix, and then add 100 μL of different possible coexisting interfering substances (concentration of 10 mM). The total volume of the system is 1 mL. After reacting at room temperature for 1 min, the fluorescence spectrum of the system in the range of 360–850 nm is tested at an excitation wavelength of 350 nm and an emission wavelength of 680 nm.

[0059] like Figure 5 As shown, the quenching efficiency induced by sodium tripolyphosphate (a) at the same concentration is significantly higher than that induced by disodium hydrogen phosphate (b), sodium dihydrogen phosphate (c), sodium phosphate (d), sodium thiocyanate (e), acesulfame (f), potassium sorbate (g), and glutathione (h), indicating that chromium selenide quantum dots have good selectivity for the detection of sodium tripolyphosphate.

[0060] Example 6: The chromium selenide quantum dots prepared in Example 1 were used for detection in this example.

[0061] The detection procedure for sodium tripolyphosphate: Add 850 μL of a buffer solution (pH=8) consisting of a Tris-HCl buffer system to a 1 mL centrifuge tube, then add 50 μL of the prepared chromium selenide quantum dots, vortex to mix, and then add 100 μL of sodium tripolyphosphate standard solutions of different concentrations (0.01, 0.05, 0.1, 0.5, 1, 2 mM). The total volume of the system is 1 mL. After reacting at room temperature for 1 min, the fluorescence spectrum of the system in the range of 360–850 nm is tested at an excitation wavelength of 350 nm and an emission wavelength of 680 nm.

[0062] Based on the above optimal reaction conditions, reactions were carried out with sodium tripolyphosphate standard solutions of different concentrations to obtain... Figure 6 The fluorescence response diagram is shown. The fluorescence quenching efficiency [(F0-F) / F0] of chromium selenide quantum dots is calculated to obtain... Figure 7The linear relationship between the fluorescence quenching efficiency [(F0-F) / F0] of chromium selenide quantum dots and the concentration of sodium tripolyphosphate was shown, revealing a linear range of 1–200 μM and a detection limit of 0.1 μM for sodium tripolyphosphate. Based on this linear relationship, the concentration of sodium tripolyphosphate in an unknown test solution can be detected.

[0063] Example 7: (1) Preparation of sulfur quantum dots: Weigh 2.8 g of sublimed sulfur into a round-bottom flask, then add polyethylene glycol-400 (6 mL) and deionized water (90 mL) sequentially. While stirring, slowly add 10 mL of sodium hydroxide solution (0.8 g / mL). After the sublimed sulfur is completely dissolved, react at a constant temperature of 60–80°C for 60–84 h. Cool to room temperature, and transfer the resulting reaction solution into a dialysis bag with a molecular weight cutoff of 3500 Da for dialysis. Monitor the pH in the dialysis bag with pH paper until the pH in the bag is approximately 7. Stop dialysis to obtain sulfur quantum dots. Store the dialyzed sulfur quantum dots at 4°C for later use.

[0064] (2) Preparation of sodium tripolyphosphate solution: Weigh sodium tripolyphosphate powder (0.2943 g) into a centrifuge tube, add deionized water (4 mL), vortex and mix until dissolved to obtain a 200 mM sodium tripolyphosphate solution. Then dilute with water to obtain 50, 100, 150 and 200 mM sodium tripolyphosphate solutions.

[0065] (3) Implementation of the ratiometric fluorescence analysis method based on sulfur quantum dots assisted by sodium tripolyphosphate: Add 750 μL of acetate-sodium acetate buffer solution (pH 3.6) to a 1 mL centrifuge tube, then add 50 μL of sulfur quantum dots prepared in step (1), vortex mix, then add 100 μL of sodium tripolyphosphate solution of different concentrations prepared in step (2), vortex mix, and finally add 100 μL of UO22+ standard solution of different concentrations (10, 50, 100, 200, 600 μM), react at room temperature for 10 min, and then measure the fluorescence spectrum of the system.

[0066] like Figure 8 As shown, when the sodium tripolyphosphate concentration is 200 mM, the ratio of the fluorescence peak enhancement value at 520 nm (UO22+ autofluorescence) to the fluorescence intensity at 440 nm (sulfur quantum dot fluorescence) (F520 / F440) has the largest slope relative to the UO22+ concentration, indicating that the sodium tripolyphosphate concentration of 200 mM has higher sensitivity. Therefore, the following experiments were conducted with a sodium tripolyphosphate concentration of 200 mM.

[0067] Example 8: (1) Implementation of the ratiometric fluorescence analysis method based on sulfur quantum dots assisted by sodium tripolyphosphate: Add 790-700 μL of acetate-sodium acetate buffer solution (pH 3.6) to a 1 mL centrifuge tube, then add 10-100 μL of sulfur quantum dots prepared in step (1) of Example 7, vortex mix, then add 100 μL of 200 mM sodium tripolyphosphate solution prepared in step (2) of Example 7, vortex mix, and finally add 100 μL of UO22+ standard solution of different concentrations (10, 50, 100, 200, 600 μM), react at room temperature for 10 min, and then measure the fluorescence spectrum of the system.

[0068] like Figure 9 As shown, when the sulfur quantum dot volume is 20 μL, the slope of the ratio (F520 / F440) relative to the UO22+ concentration is the largest, indicating that the sulfur quantum dot volume of 20 μL has higher sensitivity. The following experiments were conducted with a sulfur quantum dot volume of 20 μL.

[0069] Example 9: (1) Implementation of the ratiometric fluorescence analysis method based on sulfur quantum dots assisted by sodium tripolyphosphate: Add 780 μL of acetate-sodium acetate buffer solution (pH 2.6-7.6) with different pH to a 1 mL centrifuge tube, then add 20 μL of sulfur quantum dots prepared in step (1) of Example 7, vortex mix, then add 100 μL of 200 mM sodium tripolyphosphate solution prepared in step (2) of Example 7, vortex mix, and finally add 100 μL of UO22+ standard solution (200 μM), react at room temperature for 10 min and then measure the fluorescence spectrum of the system.

[0070] like Figure 10 As shown, the ratio (F520 / F440) of the acetate-sodium acetate buffer solution reaches its maximum when the pH is increased from 2.6 to 6.6. When the pH is further increased to 7.6, the ratio decreases instead, indicating that the acetate-sodium acetate buffer solution has higher sensitivity at pH 6.6. The following experiments were conducted at pH 6.6.

[0071] Example 10: (1) Implementation of the ratiometric fluorescence analysis method based on sulfur quantum dots assisted by sodium tripolyphosphate: Add 780 μL of acetate-sodium acetate buffer solution (pH 6.6) with different pH to a 1 mL centrifuge tube, then add 20 μL of sulfur quantum dots prepared in step (1) of Example 7, vortex mix, then add 100 μL of 200 mM sodium tripolyphosphate solution prepared in step (2) of Example 7, vortex mix, and finally add 100 μL of UO22+ standard solution (200 μM). After reacting at room temperature for 3 to 20 min, measure the fluorescence spectrum of the system.

[0072] like Figure 11 As shown, the ratio (F520 / F440) reaches its maximum within 3 minutes. With further extension of time, the ratio plateaus, indicating that the system has reached equilibrium. The following procedure was carried out with a reaction time of 3 minutes.

[0073] Example 11: Detection of UO22+: Add 780 μL of acetate-sodium acetate buffer solution (pH 6.6) at different pH values ​​to a 1 mL centrifuge tube, then add 20 μL of sulfur quantum dots prepared in step (1) of Example 7, vortex mix, then add 100 μL of 200 mM sodium tripolyphosphate solution prepared in step (2) of Example 7, vortex mix, and finally add 100 μL of UO22+ standard solutions of different concentrations (0, 1, 5, 10, 50, 100, 200, 600, 1000, 2000, 3000 μM), react at room temperature for 3 min, and then measure the fluorescence spectrum of the system.

[0074] like Figure 12 As shown, the fluorescence intensity of the fluorescence emission peaks at 498, 520, 542, and 570 nm, which belong to UO22+ itself, gradually increases with increasing UO22+ concentration, while the fluorescence peak intensity at 440 nm, which belongs to sulfur quantum dots, remains almost unchanged. The ratio (F520 / F440) is linearly related to the UO22+ concentration in the range of 0–300 μM (e.g., ...). Figure 13 As shown in the figure, the detection limit is 12.8 nM.

[0075] Example 12: Select common metal ions (a: UO2) 2+ b: Al 3+ c: Ag + ;d:Mn 2+ e: Cu 2+ f: Eu 3+ g: Fe 2+ h: Fe 3 + i: Mg 2+ ;j:Ce 3+ ;k:Na + ;l:Ni 2+ Conduct interference tests, such as Figure 14 As shown, with UO2 2+ The resulting ratio (F) 520 / F 440 Compared to the control group, the changes caused by interfering substances were smaller, consistent with the blank, indicating that the sodium tripolyphosphate-assisted sulfur quantum dot-based ratiometric fluorescence analysis method was used for UO2 analysis. 2+It has high selectivity in detection and can avoid interference from other metal impurities in the test solution.

[0076] This invention provides a phosphate-assisted uranyl ion ratiometric fluorescence detection method, such as... Figure 15 , Figure 16 As shown, UO2 2+ It can quench the fluorescence of chromium selenide quantum dots and zinc sulfide quantum dots, while phosphate anions can act as a recognition agent for UO2. 2+ and enhance UO2 2+ An auxiliary medium with self-fluorescence is used to detect residual UO2 in aquatic environments and food. 2+ The detection of UO2 was also performed in this invention. Other quantum dots were also tested, and so far only chromium selenide quantum dots and zinc sulfide quantum dots were found to be compatible with UO2. 2+ The aforementioned fluorescence phenomenon can occur.

[0077] Example 13: Effect of Chromium Selenide Quantum Dot Addition Amount on Chromium Selenide Quantum Dot-Based Detection System: (1) Preparation of sodium selenosulfate precursor solution: Measure 25 mL of nitrogen-purged deionized water into a 50 mL round-bottom flask, maintain an inert environment, and heat the nitrogen-purged deionized water to 80°C under stirring. Then, add 5 mL of sodium sulfite solution (0.8 M) dropwise to the nitrogen-purged deionized water and stir to mix. Finally, add 50 mg of selenium powder to the above mixed solution, stir, and reflux at 80°C for 5 hours.

[0078] (2) Synthesis of chromium selenide quantum dots: Under stirring conditions, 10 mL of chromium acetate solution (70 mM) was slowly added dropwise to 180 mL of nitrogen-purged deionized water solution, maintaining an inert environment, and heated to 100°C and refluxed. Then, 10 mL of thioglycolic acid solution (180 mM) was added to the above mixed solution and mixed thoroughly. Afterward, sodium hydroxide solution (1 M) was slowly added dropwise to the mixed solution until the solution just turned colorless. After continuing reflux for 1 hour, 5 mL of sodium selenose sulfate precursor solution was added dropwise to the mixed solution, and reflux was continued for 4 hours.

[0079] (3) Detection process of UO22+: Add acetate-sodium acetate buffer solution (pH=5) to a 1 mL centrifuge tube, then add different volumes of the prepared chromium selenide quantum dots, vortex mix, then add 100 μL of sodium tripolyphosphate solution (200 mM), and vortex mix. Finally, add 100 μL of uranyl ion standard solutions of different concentrations (0, 50, 100, 200, 300, 500, 700, 1000 μM), the total volume of the system is 1 mL, react at room temperature for 15 min, and then test the fluorescence spectrum of the system in the range of 350-850 nm at an excitation wavelength of 300 nm and an emission wavelength of 680 nm.

[0080] like Figure 17 As shown, the volume of the added chromium selenide quantum dots affects UO2. 2+ The sensitivity of the detection system is significantly affected, with 20 μL showing the best detection effect. As the amount of chromium selenide quantum dots added increases, the detection effect gradually decreases. Therefore, the preferred volume of added chromium selenide quantum dots is 20 μL.

[0081] Example 14: Effect of phosphate anion concentration on a chromium selenide quantum dot-based detection system: This embodiment uses the chromium selenide quantum dots prepared in Example 13 for testing.

[0082] UO2 2+ The detection procedure was as follows: Acetic acid-sodium acetate buffer solution (pH=5) was added to a 1 mL centrifuge tube, followed by 20 μL of the prepared chromium selenide quantum dots. After vortexing, 100 μL of sodium tripolyphosphate solution of different concentrations was added and vortexed again. Finally, 100 μL of uranyl ion standard solutions of different concentrations (0, 50, 100, 200, 300, 500, 700, 1000 μM) were added, bringing the total system volume to 1 mL. After reacting at room temperature for 15 min, the fluorescence spectrum of the system in the range of 350–850 nm was measured at an excitation wavelength of 300 nm and an emission wavelength of 680 nm.

[0083] like Figure 18 As shown, the concentration of added sodium tripolyphosphate affects UO2. 2+ The sensitivity of the detection system is affected to some extent. It can be found that the detection effect is best when the sodium tripolyphosphate system concentration is 30 mM.

[0084] Example 15: Effect of buffer solution pH on the detection system based on chromium selenide quantum dots: This embodiment uses the chromium selenide quantum dots prepared in Example 13 for testing.

[0085] UO2 2+The detection process was as follows: Acetic acid-sodium acetate buffer solutions of different pH values ​​were added to 1 mL centrifuge tubes, followed by 20 μL of the prepared chromium selenide quantum dots. After vortexing, 100 μL of 300 mM sodium tripolyphosphate solution was added and vortexed again. Finally, 100 μL of uranyl ion standard solutions of different concentrations (0, 50, 100, 200, 300, 500, 700, 1000 μM) were added, bringing the total system volume to 1 mL. After reacting at room temperature for 15 min, the fluorescence spectrum of the system in the range of 350–850 nm was measured at an excitation wavelength of 300 nm and an emission wavelength of 680 nm.

[0086] like Figure 19 As shown, the pH value of the buffer solution has a certain impact on the sensitivity of the sodium tripolyphosphate detection system, and the detection effect is best when the pH value of the buffer solution is 5.

[0087] Example 16: Effect of reaction time on the detection system based on chromium selenide quantum dots: This embodiment uses the chromium selenide quantum dots prepared in Example 13 for testing.

[0088] UO2 2+ The detection procedure was as follows: Acetic acid-sodium acetate buffer solution (pH=5) was added to a 1 mL centrifuge tube, followed by 20 μL of the prepared chromium selenide quantum dots. After vortexing, 100 μL of 300 mM sodium tripolyphosphate solution was added and vortexed again. Finally, 100 μL of uranyl ion standard solution (200 μM) was added, bringing the total system volume to 1 mL. After reacting at room temperature for different times, the fluorescence spectrum of the system in the range of 350–850 nm was measured at an excitation wavelength of 300 nm and an emission wavelength of 680 nm.

[0089] Figure 20 The figure shows the effect of reaction time on the sodium tripolyphosphate detection system. The optimal detection effect can be basically achieved with a reaction time of 12 min, and a longer reaction time has no significant impact on the detection effect.

[0090] Example 17: Detection performance of the chromium selenide quantum dot-based detection system: Based on Examples 13-16, the optimal reaction conditions for the detection system based on chromium selenide quantum dots can be determined as follows: the volume of chromium selenide quantum dots added is 20 μL, the concentration of sodium tripolyphosphate system is 30 mM, the pH of the buffer solution is 5, and the reaction time is 12 min.

[0091] Based on the above optimal reaction conditions, reactions were carried out with sodium tripolyphosphate standard solutions of different concentrations (0, 1, 5, 10, 50, 100, 200, 500, 1000 μM) to obtain... Figure 21 The fluorescence response diagram shown is used to calculate F.520 / F 680 ,get Figure 22 The F shown 520 / F 680 The linear relationship between sodium tripolyphosphate concentration and the detection limit is 30 nM, with a linear range of 0-100 μM. Based on this linear relationship, the concentration of sodium tripolyphosphate in an unknown test solution can be detected.

[0092] Example 18: Detection effect of the chromium selenide quantum dot-based detection system on interfering substances: To determine the influence of interfering substances on the fluorescence signal in the phosphate-assisted uranyl ion ratiometric fluorescence detection method provided by this invention, based on the optimal reaction conditions of Example 5, common metal ions (Ag) were selected. + Ce 3 + Al 3+ Fe 3+ Fe 2+ Eu 3+ Ni 2+ Mg 2+ , Mn 2+ Na + Interference testing was conducted at (20 μM), and the results are as follows: Figure 23 As shown, with UO2 2+ The resulting ratio (F) 520 / F 680 Compared to the control group, the changes caused by interfering substances were smaller, consistent with the blank control, indicating that the detection system has good selectivity.

[0093] Example 19: Effect of zinc sulfide quantum dot addition amount on zinc sulfide quantum dot-based detection system: (1) Preparation of zinc sulfide quantum dots: Under stirring conditions, 20 mL of zinc sulfate solution (0.625 M) and 20 mL of manganese chloride solution (50 mM) were added sequentially to a 100 mL round-bottom flask, and nitrogen gas was purged for 30 minutes to remove dissolved oxygen. Then, 3 g of sodium sulfide nonahydrate solution was dissolved in deionized water that had been purged with nitrogen to remove oxygen, and this sodium sulfide solution was slowly added dropwise to the above mixed solution. After stirring for another 30 minutes, 10 mL of ethanol solution (62.5 mM) containing (3-mercaptopropyl)triethoxysilane was slowly added dropwise to the mixed solution, and the reaction was continued for 20 hours.

[0094] (2) UO2 2+The detection process was as follows: A certain volume of acetate-sodium acetate buffer solution (pH=5) was added to a 1 mL centrifuge tube, followed by different volumes of the prepared zinc sulfide quantum dots. After vortexing and mixing, 100 μL of 200 mM sodium tripolyphosphate solution was added and vortexed again. Finally, 100 μL of uranyl ion standard solutions of different concentrations (200, 300, 500, 700, 1000 μM) were added, bringing the total system volume to 1 mL. After reacting at room temperature for 10 min, the fluorescence spectrum of the system was measured in the range of 350–650 nm at an excitation wavelength of 300 nm and an emission wavelength of 600 nm.

[0095] like Figure 24 As shown, the volume of zinc sulfide quantum dots added affects UO2. 2+ The sensitivity of the detection system is affected to a certain extent. The detection effect is best at 20 μL. As the amount of chromium selenide quantum dots added increases, the detection effect gradually decreases. Therefore, the volume of chromium selenide quantum dots added is preferably 20 μL.

[0096] Example 20: Effect of phosphate anion concentration on a zinc sulfide quantum dot-based detection system: This embodiment uses the zinc sulfide quantum dots prepared in Example 7 for testing.

[0097] UO2 2+ The detection procedure was as follows: 780 μL of acetate-sodium acetate buffer solution (pH=5) was added to a 1 mL centrifuge tube, followed by 20 μL of the prepared zinc sulfide quantum dots. After vortexing, 100 μL of sodium tripolyphosphate solution of different concentrations was added and vortexed again. Finally, 100 μL of uranyl ion standard solutions of different concentrations (200, 300, 500, 700, 1000 μM) were added, bringing the total system volume to 1 mL. After reacting at room temperature for 10 min, the fluorescence spectrum of the system was measured in the range of 350–650 nm at an excitation wavelength of 300 nm and an emission wavelength of 600 nm.

[0098] Figure 25 The figure shows the effect of the added sodium tripolyphosphate concentration on UO2. 2+ The sensitivity of the detection system was affected, and it was found that the detection effect was best when the sodium tripolyphosphate system concentration was 30 mM.

[0099] Example 21: Effect of buffer solution pH on zinc sulfide quantum dot-based detection system: This embodiment uses the zinc sulfide quantum dots prepared in Example 7 for testing.

[0100] UO2 2+The detection procedure was as follows: 780 μL of acetate-sodium acetate buffer solution with different pH values ​​was added to a 1 mL centrifuge tube, followed by 20 μL of the prepared zinc sulfide quantum dots. After vortexing and mixing, 100 μL of 300 mM sodium tripolyphosphate solution was added and vortexed again. Finally, 100 μL of uranyl ion standard solutions of different concentrations (200, 300, 500, 700, 1000 μM) were added, bringing the total system volume to 1 mL. After reacting at room temperature for 10 min, the fluorescence spectrum of the system was measured in the range of 350–650 nm at an excitation wavelength of 300 nm and an emission wavelength of 600 nm.

[0101] Figure 26 The figure shows the effect of buffer solution pH on the sensitivity of the detection system based on zinc sulfide quantum dots. The detection effect is best when the buffer solution pH is 6.

[0102] Example 22: Effect of reaction time on the detection system based on zinc sulfide quantum dots: This embodiment uses the chromium selenide quantum dots prepared in Example 7 for testing.

[0103] UO2 2+ The detection procedure was as follows: 780 μL of acetate-sodium acetate buffer solution (pH=6) was added to a 1 mL centrifuge tube, followed by 20 μL of the prepared zinc sulfide quantum dots. After vortexing, 100 μL of 300 mM sodium tripolyphosphate solution was added and vortexed again. Finally, 100 μL of uranyl ion standard solution (500 μM) was added, bringing the total system volume to 1 mL. After reacting at room temperature for a certain time, the fluorescence spectrum of the system was measured in the range of 350–650 nm at an excitation wavelength of 300 nm and an emission wavelength of 600 nm.

[0104] Figure 27 The figure shows the effect of reaction time on the sodium tripolyphosphate detection system. A reaction time of 1 min is sufficient to achieve the best detection effect, and a longer reaction time has no significant impact on the detection effect.

[0105] Example 23: Detection effect of the zinc sulfide quantum dot-based detection system: Based on Examples 7-10, the optimal reaction conditions can be determined as follows: the volume of zinc sulfide quantum dots added is 20 μL, the concentration of sodium tripolyphosphate system is 30 mM, the pH of the buffer solution is 6, and the reaction time is 1 min.

[0106] Based on the above optimal reaction conditions, reactions were carried out with sodium tripolyphosphate standard solutions of different concentrations (0, 1, 5, 10, 50, 100, 200, 300, 500, 700, 1000, 2000, 3000 μM) to obtain... Figure 28The fluorescence response diagram shown is used to calculate F. 520 / F 600 ,get Figure 29 The F shown 520 / F 600 The linear relationship between sodium tripolyphosphate concentration and the detection limit is 9.6 nM, with a linear range of 0-100 μM. Based on this linear relationship, the concentration of sodium tripolyphosphate in an unknown test solution can be detected.

[0107] Example 24: Detection effect of the zinc sulfide quantum dot-based detection system on interfering substances: To determine the influence of interfering substances on the fluorescence signal in the phosphate-assisted uranyl ion ratiometric fluorescence detection method provided by this invention, further based on the optimal reaction conditions of Example 131, different metal ions (Ce) were used. 3 + Al 3+ Fe 3+ Fe 2+ Eu 3+ Ni 2+ Mg 2+ , Mn 2+ Na + The sample (20 μM) was tested, and the test results are as follows: Figure 30 As shown, other common metal ions do not produce corresponding interference.

[0108] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A fluorescence analysis method, characterized in that: The method is used to detect the content of sodium tripolyphosphate. The method includes the following steps: mixing the test solution with chromium selenide quantum dots, reacting, and obtaining the content of sodium tripolyphosphate in the test solution by detecting the fluorescence intensity of the system.

2. The fluorescence analysis method according to claim 1, characterized in that: The chromium selenide quantum dots are synthesized via a hydrothermal method using chromium salt precursors, sodium selenosulfate precursors, and stabilizers. The chromium salt precursor is one or more of chromium acetate, chromium chloride, chromium nitrate, and chromium sulfate; The preparation process of the sodium selenosulfate precursor includes the following steps: mixing sodium sulfite solution and selenium powder, and then refluxing to obtain sodium selenosulfate. The stabilizer is one or more of the following: thioglycolic acid, 3-mercaptopropionic acid, 4-mercaptobutyric acid, 5-mercaptovalerate, and 6-mercaptohexanoic acid.

3. The fluorescence analysis method according to claim 1, characterized in that: The method includes the following steps: adding a buffer solution to a centrifuge tube, then adding chromium selenide quantum dots, vortexing and mixing, adding the test solution, reacting at room temperature for a certain time, and then testing the fluorescence spectrum of the system in the range of 360–850 nm at an excitation wavelength of 350 nm and an emission wavelength of 680 nm. The fluorescence quenching efficiency of chromium selenide quantum dots [(F0-F) / F0] is linearly related to the concentration of sodium tripolyphosphate.

4. A fluorescence analysis method, characterized in that: The method is used to detect uranyl ions. The method includes the following steps: mixing sulfur quantum dots, sodium tripolyphosphate and the test solution in a buffer solution, reacting them, and obtaining the content of uranyl ions in the test solution by detecting the fluorescence intensity of the system.

5. The fluorescence analysis method according to claim 4, characterized in that: The preparation process of the sulfur quantum dots includes the following steps: Sublimed sulfur is placed in a container, and then polyethylene glycol-400 and deionized water are added sequentially. Sodium hydroxide solution is slowly added dropwise under stirring. After the sublimed sulfur is completely dissolved, the reaction is carried out at a constant temperature of 60-80°C for 60-84 hours. After cooling to room temperature, the resulting reaction solution is transferred to a dialysis bag with a molecular weight cutoff of 3500 Da for dialysis to obtain sulfur quantum dots.

6. The fluorescence analysis method according to claim 4, characterized in that: The reaction time after mixing is 3 to 20 minutes. After the reaction is completed, the fluorescence peak of the system in the range of 370 to 650 nm is tested at an excitation wavelength of 300 nm and an emission wavelength of 500 nm. The ratio of the fluorescence enhancement value at 520 nm to the fluorescence intensity at 440 nm is linearly related to the concentration of uranyl ions.

7. A fluorescence analysis method, characterized in that: The method is used to detect uranyl ions, and the detection includes the following steps: mixing fluorescent quantum dots and phosphate anion solution, then adding the test solution, and after the reaction, obtaining the content of uranyl ions in the test solution by measuring the fluorescence intensity of the test system; the fluorescent quantum dots are chromium selenide quantum dots or zinc sulfide quantum dots.

8. The fluorescence analysis method according to claim 7, characterized in that: The detection method includes the following steps: adding a buffer solution to a centrifuge tube, then adding the fluorescent quantum dots, vortexing and mixing, adding a phosphate anion solution, vortexing and mixing, then adding the test solution, reacting at room temperature for a certain time, and then testing the fluorescence spectrum.

9. The fluorescence analysis method according to claim 8, characterized in that: The fluorescent quantum dots are chromium selenide quantum dots. The fluorescence spectrum of the system was measured in the range of 360–850 nm at an excitation wavelength of 300 nm and an emission wavelength of 680 nm. 520 / F 680 It has a linear relationship with the concentration of uranyl ions.

10. The fluorescence analysis method according to claim 8, characterized in that: The fluorescent quantum dots are zinc sulfide quantum dots. The fluorescence spectrum of the system was measured in the range of 350–650 nm at an excitation wavelength of 300 nm and an emission wavelength of 600 nm. 520 / F 600 It has a linear relationship with the concentration of uranyl ions.

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