Method for preparing a fluorescence-enhanced uranyl ion probe

Abstract

The application belongs to the technical field of ion detection, and particularly relates to a preparation method of a rapid detection uranyl ion ratio type fluorescent probe, comprising the following steps: dissolving rhodamine B and phosphorus oxychloride in 1,2-dichloroethane to obtain product 1; dissolving the product 1 in acetonitrile, adding 2-aminobenzimidazole and triethylamine, and stirring under heating; after the reaction is completed, column chromatography purification is carried out, and vacuum drying is carried out to obtain the target product fluorescent probe RBN; and the fluorescent probe RBN is dissolved in DMSO to prepare a mother liquor. The fluorescent probe has the advantages of rapid response to uranyl ions, simple synthesis route, simple detection equipment and method, and the like, and can be used for qualitative and quantitative detection of uranyl ions in an environment and a biological system.

Description

Technical Field

[0001] This invention belongs to the field of ion detection technology, specifically relating to a method for preparing a fluorescence-enhanced uranyl ion probe. Background Technology

[0002] Uranium is a naturally occurring radioactive element that has been widely used in nuclear weapons, nuclear fuel plants, and medical applications. However, due to its high radioactivity and chemical toxicity, while uranium brings benefits, it also causes serious environmental pollution and the risk of accidental nuclear accidents. In nature, uranium often exists in a water-soluble and stable hexavalent oxide state, called uranyl ion (UO2). 2+ ). So far, UO2 2+ Detection methods mainly include atomic absorption spectrometry, high-performance liquid chromatography, and inductively coupled plasma (ICP-C). However, these methods have drawbacks such as expensive equipment and relatively cumbersome sample preparation. In recent years, fluorescent probe detection has advantages such as relatively simple required equipment, high sensitivity, specificity, ease of use, and visualization. It has shown great potential in rapid detection in food and environmental ecosystems and in real-time in-situ imaging of cells, tissues, and living organisms. Although some methods are used for UO2... 2+ Fluorescent probes for detection have been developed, but most detection signals are fluorescence-quenched, making them highly susceptible to interference from the surrounding environment and instrument operation, significantly reducing their practical application value. Therefore, there is an urgent need to develop a fluorescence-enhanced detection method for uranyl ions (UO2). 2+ Fluorescent probes, which are useful for UO2 in ecological environments and biological systems. 2+ The detection of this substance has significant scientific value and promising application prospects. Summary of the Invention

[0003] For the detection of UO2 using existing fluorescent probes 2+ To address the problems encountered in the process, this invention provides a method for preparing a fluorescence-enhanced uranyl ion probe. This method is simple in steps, has a high yield of the target product, a fast response speed, good selectivity, high sensitivity, and a low detection limit.

[0004] To solve the above-mentioned technical problems, the present invention is implemented as follows:

[0005] A method for preparing a fluorescence-enhanced uranyl ion probe includes the following steps:

[0006] (1) Rhodamine B and phosphorus oxychloride were dissolved in 1,2-dichloroethane, heated and stirred, and after the reaction was completed, cooled to room temperature and dried under vacuum to obtain product 1.

[0007] (2) Dissolve the product 1 obtained in step (1) in acetonitrile, add 2-aminobenzimidazole and triethylamine, heat and stir, after the reaction is completed, purify by column chromatography, and dry under vacuum to obtain the target product fluorescent probe RBN.

[0008] Furthermore, in step (1), the molar ratio of Rhodamine B to phosphorus oxychloride is 1:2.

[0009] Furthermore, in step (2), the molar ratio of product 1 to 2-aminobenzimidazole is 1:1.2.

[0010] Furthermore, in step (2), the fluorescent probe RBN has the following structural formula: Molecular formula: C 35 H 35 N5O2.

[0011] Further, in step (1), Rhodamine B and phosphorus oxychloride are dissolved in 1,2-dichloroethane and heated to 83°C and stirred for 3 hours; in step (2), product 1 is dissolved in acetonitrile, 2-aminobenzimidazole is added, and the mixture is heated to 81°C and stirred for 5 hours.

[0012] Furthermore, in step (2), the solvent is removed from the purified product by rotary evaporation.

[0013] Furthermore, in step (2), the mobile phase for column chromatography separation is dichloromethane and methanol with a volume ratio of 120:1.

[0014] The specific reaction process of the fluorescent probe obtained by the above-mentioned method for preparing the fluorescence-enhanced uranyl ion probe is as follows:

[0015]

[0016] This invention uses Rhodamine B, phosphorus oxychloride, 2-aminobenzimidazole, and triethylamine to prepare a fluorescent probe. This probe, in the presence of uranyl ions under ethanol:Tris (4:6) conditions, exhibits a significant fluorescence change with increasing uranyl ion concentration. The probe demonstrates rapid response, high selectivity, and high sensitivity for uranyl ion detection. Compared to some existing detection technologies, the chemical fluorescent probe of this invention requires less investment, has a simpler synthesis route, is easier to process, and can directly and rapidly identify uranyl ions in the ethanol:Tris (4:6) system, showing potential application value, especially in environmental water samples and biological systems. The fluorescent probe prepared in this invention is a spirocyclic Rhodamine derivative; upon binding with uranyl ions, its fluorescence color changes from colorless to red. This color change provides a simple, rapid, and reliable method for highly selective and sensitive visual detection of trace uranyl (UO2). 2+ The probe can detect uranyl ions without requiring any complex instruments. Moreover, it exhibits excellent selectivity for uranyl ions, specifically recognizing them, and has a rapid response time, with fluorescence intensity reaching equilibrium within 1 second. Attached Figure Description

[0017] The present invention will now be described in detail through specific embodiments. These embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art. As used throughout the specification and claims, the terms "comprising" or "including" are open-ended and are interpreted as "comprising but not limited to". The following description is a preferred embodiment for carrying out the invention; however, this description is intended to illustrate the general principles of the specification and is not intended to limit the scope of the invention. The scope of protection of the invention is determined by the appended claims. Unless otherwise specified, all reagents and materials used in the present invention are commercially available.

[0018] Figure 1 The NMR spectrum of the prepared fluorescent probe RBN is shown below.

[0019] Figure 2 The NMR C spectrum of the prepared fluorescent probe RBN;

[0020] Figure 3 The fluorescence emission spectra of the fluorescent probe RBN are shown for different uranyl ion concentrations.

[0021] Figure 4 The figures show the fitted curve of the fluorescence intensity of the fluorescent probe RBN as a function of uranyl ion concentration and the corresponding function graph.

[0022] Figure 5 This is a time-scan graph showing the response of the fluorescent probe RBN to uranyl ions;

[0023] Figure 6 This demonstrates the selectivity of the fluorescent probe RBN for other analytes.

[0024] The concentration of the added ions was 2 × 10⁻⁶. -2 mol / L, 420 nm is the excitation wavelength. (Note: The probe concentration is 10 μM; UO2) 2+ Response time is less than 1 second. Detailed Implementation

[0025] Example 1

[0026] (1) Preparation of product 1

[0027] Rhodamine B (10 mmol) and phosphorus oxychloride (20 mmol) were added to a 20 mL round-bottom flask containing 1,2-dichloroethane, and the mixture was heated to 83°C and stirred for 3 hours. After cooling to room temperature, the mixture was dried under vacuum, and the solvent was removed by rotary evaporation to obtain product 1.

[0028] (2) A fluorescent probe was synthesized using products 1 and 2-aminobenzimidazole.

[0029] Product 1 (3 mmol) was dissolved in 10 mL of acetonitrile, and 2-aminobenzimidazole (4.5 mmol) and triethylamine were added. The mixture was heated to 81 °C and stirred for 5 hours. The reaction was detected by TLC. After the reaction was complete, the product was purified by column chromatography using a mobile phase of dichloromethane:methanol (v / v) at a ratio of 120:1. The purified product was then desolvated by rotary evaporation and dried under vacuum to obtain the fluorescent probe RBN.

[0030] A 1 mM stock solution was prepared by dissolving the fluorescent probe RBN (1 mmol) in DMSO. Detection of uranyl ions:

[0031] Take 12 5mL sample vials and add 20μL of the fluorescent probe solution RBN (10μM concentration) prepared in Example 1 to each vial. Then, add [UO2] to each of the 12 sample vials. 2+ ]=0(a), 2×10 -6 mol / L(b), 4.5×10 -6 mol / L(c), 6.8×10 -6 mol / L(d), 9×10 -6 mol / L(e), 1.1×10 -5 mol / L(f), 1.3×10 -5 mol / L(g), 1.6×10 -5 mol / L(h), 1.8×10 -5 mol / L(i), 2×10 -5 mol / L(j), 2.2×10 -5 mol / L(k), 2.5×10 -5 A uranyl ion solution of mol / L (l) was stirred at room temperature for 1 second, and the fluorescence intensity of these samples was measured at an excitation wavelength of 420 nm. The fluorescence intensity emission spectrum changes of the 12 samples are shown in the figure. Figure 3 The measurement results showed that the fluorescence intensity of the fluorescent probe at 590 nm gradually increased with the gradual increase of uranyl ion concentration. Based on... Figure 3 The fluorescence intensity change values ​​can be used to plot the corresponding fitted function curve and the corresponding function graph (y=ax+b, a=141.039b=109.16, R). 2 =0.9953) See Figure 4 Add 20 μL of probe solution (the fluorescent probe concentration is 10 μM) to the sample vial, and add [UO2] solution. 2+ ] = 2 × 10 -5The response time of the probe to uranyl ions was measured at an emission wavelength of 590 nm using a concentration of mol / L (250 μM). The results showed that the response time to uranyl ions was less than 1 second, and the fluorescence intensity remained stable for 120 seconds. (See [reference needed]). Figure 5 .

[0032] Other analyte comparison tests:

[0033] Take 13 5mL sample vials and add 20μL of the fluorescent probe solution RBN prepared in Example 1 (the concentration of the fluorescent probe is 10μM). Then, add 2×10⁻⁶ μL of the solution to each vial. -5 mol / L other analytes and UO2 2+ Take 25 μL of each sample and add it to the remaining 12 sample vials; sample 1 serves as the blank sample. Then, measure the fluorescence emission intensity of each of the 15 samples at an excitation wavelength of 420 nm and an emission wavelength of 590 nm. The results are shown below. Figure 6 The results showed that the other analytes had no significant effect on the intensity of the prepared fluorescent probe.

[0034] The above embodiments are used to explain and illustrate the present invention, but not to limit the present invention. Any modifications and changes made to the present invention within the spirit and scope of the claims fall within the protection scope of the present invention.

Claims

1. The use of a spirocyclic rhodamine derivative as a fluorescence-enhanced uranyl ion probe, characterized in that, The derivative has the following structure: 。

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