An aniline-specific fluorescent probe based on AIE performance, its preparation method and application
A simple and cost-effective AIE-based fluorescent probe provides rapid and selective detection of benzeneamines, overcoming the limitations of existing methods by enabling sensitive and stable detection in both liquid and gas phases.
Patent Information
- Application Number
- CN202410342655.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-25
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2044-03-25
AI Technical Summary
The existing aniline detection methods are complex, time-consuming and low selectivity, making it difficult to achieve fast, simple and highly selective detection.
A specific fluorescence probe of aniline based on AIE performance was developed, and the TPEN probe was prepared by a method with simple synthetic route and mild reaction conditions. The nucleophilic addition and elimination reaction with aniline were used to form Schiff base compounds, achieving high sensitivity and strong anti-interference fluorescence detection.
It realizes accurate identification of aniline in complex systems, has high sensitivity, fast response and low cost detection effects, can be stable under wide pH conditions, is suitable for portable detection in aqueous solutions and air, with a low detection limit of up to 0.2μM.
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Figure CN118084820B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of fluorescence detection, and particularly relates to an aniline-specific fluorescent probe based on AIE performance, a preparation method thereof, and an application thereof. Background Art
[0002] VOCs are volatile organic compounds, which are diverse in types and have characteristics such as mobility, persistence, and toxicity. Therefore, they can cause serious fatal injuries to the human body. Aniline is an aromatic amine compound in VOCs, which is a colorless or light yellow liquid and has a strong benzene odor. At the same time, it is also an important chemical intermediate and has been widely used as an intermediate for many chemicals or solvents in various chemical reactions in the chemical, pharmaceutical, food, and military industries. However, the extensive use of aniline has disrupted the environmental ecological balance. In particular, aniline is highly toxic and can cause harm to the human body even at a concentration as low as the micromolar level, such as upper respiratory tract irritation. Therefore, aniline is classified as a carcinogen. Especially, aniline can be derived from many industrial sources and can be found in various places, such as surface water. Therefore, in order to be able to give an early warning quickly, it is crucial to develop a detection method that can detect low-concentration aniline.
[0003] Currently, there are various analytical techniques for detecting aniline, such as high-performance liquid chromatography (HPLC), voltammetry, capillary zone electrophoresis (CZE), laser desorption / ionization mass spectrometry (LDI-MS), and liquid chromatography-mass spectrometry (LC-MS). However, most of these methods have limitations such as complex operation and time-consuming. Fluorescence spectrometry has the advantages of high sensitivity, good specificity, and fast response time. Therefore, fluorescence spectrometry for detecting aniline has certain application prospects. Therefore, researchers have made considerable efforts in developing fluorescent probes for detecting these anilines. Although great progress has been made in the research on the fluorescence detection of aniline, many reported probes still have problems such as a cumbersome synthesis process, low selectivity, and long response time. Therefore, there is a great need to develop a simple, highly selective, and fast-responsive fluorescent probe for detecting aniline. Summary of the Invention
[0004] The purpose of the present invention is to provide an aniline-specific fluorescent probe based on AIE performance, a preparation method thereof, and an application thereof in view of the deficiencies in the prior art.
[0005] The present invention provides a fluorescent probe with a simple synthesis route, mild reaction conditions, and low cost; it also provides a fluorescent probe with high sensitivity, good selectivity, strong anti-interference ability, and capable of accurately identifying aniline in a complex system, and the structure is as follows:
[0006]
[0007] The preparation method of the aniline-specific fluorescent probe based on AIE performance includes the following steps:
[0008] Mix compound 2 and benzothiazole-2-acetonitrile in a solvent and react for 4 hours; after the reaction, spin-dry the solvent to obtain a solid crude product, and obtain the probe TPEN by column chromatography; wherein, the molar ratio of compound 2 to benzothiazole-2-acetonitrile is 1:1.15; the silica gel used in column chromatography is 200-300 mesh, and the eluent is: V ethyl acetate / V petroleum ether = 10 / 1.
[0009] Its synthetic route is:
[0010]
[0011] Stir a solution of compound 2 (1.00 g, 2.77 mmol) and benzothiazole-2-acetonitrile (0.56 g, 3.19 mmol) in ethanol (30 mL) at room temperature. Then add tetrabutylammonium hydroxide (TBAH, 0.8 M, 10 drops), stir at room temperature for 4 h, collect the precipitate, wash it 3 times with ethanol, rotary evaporate the reaction solution under reduced pressure to remove the solvent, and use ethyl acetate / petroleum ether (v / v, 1:10) as the eluent. After purification by column chromatography, obtain a solid powder of the yellow-green probe TPEN (0.91 g, yield 91%).
[0012] The mechanism of the probe of the present invention is as follows:
[0013]
[0014] The action mechanism of the fluorescent probe of the present invention is as follows. The amino group on aniline attacks the carbon-carbon double bond on TPEN through a nucleophilic addition reaction, then an elimination reaction occurs, and finally a Schiff base compound TPEN-AN is formed.
[0015] The application of the aniline-specific fluorescent probe based on AIE performance in a reagent for qualitative and quantitative detection of aniline.
[0016] The application specifically includes: Dissolve the fluorescent probe TPEN in a THF solvent to prepare a probe solution with a concentration of 1×10 -3 mol / L, then add the substance to be measured, and observe the fluorescence change at 290 nm through fluorescence detection after the reaction.
[0017] The application specifically includes: Dissolve the fluorescent probe TPEN in THF to prepare a solution with a concentration of the fluorescent probe TPEN of 1.0×10 -5 mol / L, then add the sample to be measured, detect the fluorescence intensity, and quantitatively calculate the content of aniline respectively according to the linear relationship between the fluorescence intensity and the concentration of the sample to be measured added.
[0018] The described application uses a gel to detect liquid and gaseous aniline. The specific steps are as follows: Sodium alginate and TPEN solution are used to make uniformly shaped gel beads with a concentration of 1×10 -6 mol / L. They are immersed in aniline solutions of different concentrations, and the change in fluorescence intensity is observed. When detecting gaseous aniline, the steps are as follows: A 10 mL glass bottle containing aniline solution of different concentrations is capped tightly and slightly heated for a period of time to obtain a sealed aniline gas atmosphere. The probe gel is suspended at the top of a centrifuge tube, fully exposed to aniline vapor, and the change in fluorescence intensity is observed.
[0019] The described application uses a film to detect liquid aniline. The specific steps are as follows: A small amount of TPEN probe solution is evenly applied on a glass slide and made into a TPEN solid film with a concentration of 1×10 -6 mol / L using a spin-coating device; subsequently, aniline solutions of different concentrations are dropped onto the glass slide loaded with the probe, and the color change is observed under a 365 nm ultraviolet lamp.
[0020] The specific steps for the described application to detect gaseous aniline are as follows: A simple device is made using a glass bottle and a fluorescence dish. Different concentrations of aniline solutions are added to the fluorescence dish, placed in the glass bottle, capped tightly, and slightly heated to obtain a sealed aniline gas atmosphere, and observed under an ultraviolet lamp to observe the change in its fluorescence intensity.
[0021] The beneficial effects of the present invention are as follows: The probe molecule of the present invention has the characteristics of high sensitivity and short response time for the detection of aniline, and has good stability under a wide pH condition; moreover, by loading the probe on the gel and the film, the portable detection of aniline in aqueous solution and air can be realized, and the lowest detection concentration is as low as 0.2 μM; at the same time, TPEN can also quantitatively detect aniline in water samples, so it has important application value in the fields of environmental monitoring, etc. The fluorescence probe of the present invention has the characteristics of simple synthesis route, rapid response, and little interference from the environment. Description of the Drawings
[0022] Figure 1 This is the hydrogen spectrum of the probe TPEN in deuterated CDCl3 in the present invention. The abscissa is the chemical shift (ppm), and the ordinate is the intensity;
[0023] Figure 2 This is the carbon spectrum of the probe TPEN in deuterated CDCl3 in the present invention. The abscissa is the chemical shift (ppm), and the ordinate is the intensity;
[0024] Figure 3 This is the mass spectrum of the probe TPEN in the invention. The ionization source is: ESI-;
[0025] Figure 4 This is the ultraviolet absorption spectrum of the probe TPEN in 2% THF in the present invention;
[0026] Figure 5 For the present invention, the fluorescence spectra recorded during the reaction of the probe TPEN (1×10-5 mol / L) with amine compound controls at room temperature in a 2% THF solution; the excitation wavelength was: 290 nm;
[0027] Figure 6 It is a graph of the fluorescence intensity and linear relationship after the reaction of the probe TPEN of the present invention with aniline at different concentrations;
[0028] Figure 7 For the present invention, the fluorescence spectrum of the AIE effect of the probe TPEN (1×10-5 mol / L) in a THF / H2O solvent system; the excitation wavelength was: 290 nm;
[0029] Figure 8 It is a schematic diagram of the solution corresponding to the AIE effect in a THF / H2O solvent system;
[0030] Figure 9 It is the mass spectrum of TPEN-AN in the present invention, and the ionization source is: ESI+;
[0031] Figure 10 It is a schematic diagram of the detection of aniline by a TPEN-loaded gel;
[0032] Figure 11 It is a schematic diagram of the detection of liquid aniline by a TPEN-loaded thin film;
[0033] Figure 12 It is a schematic diagram of the detection of gaseous aniline by a simple device of TPEN. Specific Embodiments
[0034] The present invention will be further described below in conjunction with examples and drawings, but the present invention is not limited by the following examples.
[0035] Example 1: Synthesis of a Tetraphenylethylene-Based AIE-Type Fluorescent Probe TPEN
[0036] A solution of compound 2 (1.00 g, 2.77 mmol) and benzothiazole-2-acetonitrile (0.56 g, 3.19 mmol) in ethanol (30 mL) was stirred at room temperature. Then tetrabutylammonium hydroxide (TBAH, 0.8 M, 10 drops) was added, and the mixture was stirred at room temperature for 4 h. The precipitate was collected and washed three times with ethanol. The reaction solution was rotary evaporated under reduced pressure to remove the solvent, and purified by column chromatography using ethyl acetate / petroleum ether (v / v, 1:10) as the eluent to obtain a yellow-green probe TPEN solid powder (1.30 g, yield 91%). As Figure 1As shown, the 1H NMR spectrum of the obtained probe structure was analyzed as follows: 1H NMR (CDCl3, 400 MHz): δ 8.83 (s, OH), δ 8.04 (d, J =, 1H), δ 7.97 (d, 1H), δ 7.51 (t, 1H), δ 7.42 (t, 1H), δ 7.37 (d, 1H), δ 7.32 (d, 1H), δ 7.14 (m, 11H), δ 7.05 (m, 6H). As Figure 2 As shown, the 13C NMR spectrum of the obtained probe structure was analyzed as follows: 13C NMR (CDCl3, 125 MHz) δ (ppm): 164.40, 155.06, 149.88, 147.85, 144.47, 144.32, 141.21, 136.33, 133.56, 132.73, 132.64, 131.70, 131.29, 129.35, 129.09, 128.50, 128.25, 127.27, 124.93, 123.00, 117.99, 105.96. As Figure 3 As shown, the mass spectrum of the obtained probe structure was: [M + H]-: 531.1531. All of these can confirm the correctness of the obtained probe structure. Figure 4 This is the UV absorption spectrum of the probe TPEN in 2% THF in the present invention.
[0037] Example 2: Selectivity of the tetraphenylethylene-based AIE fluorescent probe TPEN towards different amine substances
[0038] The TPEN fluorescent probe in Example 1 was prepared into a stock solution of 1×10-3 mol / L.
[0039] The following substances, ethylamine, diethylamine, triethylamine, ammonia, phenylhydrazine, benzylamine, cysteine, alanine, glycine, arginine, lysine, were prepared into stock solutions of 1×10-2 mol / L.
[0040] Take 11 test tubes, and sequentially add 30 μL of the above different amine stock solutions respectively. Use an equal amount of water as a substitute for the interfering substance as a control, then add 2940 μL of ultrapure water, and finally add 30 μL of the probe stock solution respectively. After shaking each solution evenly, fluorescence detection was carried out (Ex = 290 nm). Using the fluorescence intensity as the ordinate and the wavelength as the abscissa to make Figure 5 ; It can be seen from Figure 5 that only aniline can cause a ratio-type change in the fluorescence intensity of TPEN, and other amine substances have almost no interference on its fluorescence intensity, indicating that the TPEN probe has a specific response to aniline.
[0041] Example 3: Fluorescence intensity of the fluorescent probe TPEN at different concentrations of aniline
[0042] Prepare an aniline stock solution with a concentration of 1×10-3 mol / L, and control the final aniline concentration by changing the volume added to the test tube to form an aniline content of 0 - 50 equivalents. After the reaction, fluorescence detection is carried out (Ex = 290 nm), and the fluorescence intensity in each system is detected. Using the fluorescence intensity ratio as the ordinate and the aniline concentration as the abscissa, a curve is plotted and a linear relationship graph is drawn ( Figure 6 )). As Figure 6 can be seen, with the increase of aniline concentration, the fluorescence intensity at 350 nm gradually increases, and the fluorescence intensity at 510 nm gradually decreases. The calculated LOD = 3.01×10 -7 M
[0043] Example 4: Detection of aniline in different water samples by the tetraphenylethylene-based AIE fluorescent probe TPEN
[0044] Select 3 water samples for spike recovery experiments (including river water, rainwater and tap water), and use these water samples to prepare 3 solutions with an aniline concentration of 1×10-3 mol / L.
[0045] Add 30 μL of the TPEN stock solution to 3 test tubes, and dilute them to 3 mL with 2970 μL of 3 water samples respectively. Fluorescence detection is carried out at Ex = 290 nm. Calculate the recovery rate and RSD. Using the water samples as the ordinate and the aniline concentration, recovery rate, and RSD as the abscissa, Table 1 is drawn. The recovery rates are all between 99.5% - 100.5%, and the RSDs are all less than 1.
[0046] Table 1: Aniline recovery data in actual water samples
[0047]
[0048] Example 5: Exploration of the AIE effect of the tetraphenylethylene-based AIE fluorescent probe TPEN
[0049] TPEN has good solubility in THF and poor solubility in water. Select the test system as THF / H2O, and change the water content Fw of the solvent system to 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95% and 98% for testing. The results are as Figure 7 shown. When the water content increases from 0% to 50%, the fluorescence intensity of the probe gradually decreases, while when the water content increases from 60% to 98%, the fluorescence intensity of the probe itself increases significantly. The corresponding fluorescence photos of the solution are as Figure 8As shown, it is consistent with the spectral data. The change in fluorescence intensity is attributed to aggregation-induced emission (AIE). In the aggregated state of the probe TPEN, the mutual restraint between molecules hinders the free rotation of the aromatic ring and inhibits the non-radiative transition of the excited-state energy. The excited-state molecules can only return to the ground state through radiative transition, thereby producing significantly stronger fluorescence. The above results confirm that the TPEN probe has an AIE effect.
[0050] Example 6: Investigation on the Mechanism of Detection of AN by the Tetraphenylethylene-based AIE Fluorescent Probe TPEN
[0051] The amino group on aniline attacks the carbon-carbon double bond on TPEN through a nucleophilic addition reaction, followed by an elimination reaction, and finally a Schiff base compound TPEN-AN is formed. As Figure 9 shown, the mass spectrometry results of TPEN-AN can confirm this reaction mechanism.
[0052] Example 7: Application of the Tetraphenylethylene-based AIE Fluorescent Probe TPEN-loaded Gel in the Detection of Gaseous / Liquid Aniline
[0053] Uniformly shaped gel beads (c = 1×10-6 mol / L) were prepared from sodium alginate and TPEN solution, and they were immersed in aniline solutions of different concentrations to observe the change in fluorescence intensity; when detecting gaseous aniline, the steps were as follows: The 10 mL glass bottle containing aniline solution of different concentrations was tightly capped and slightly heated for a period of time to obtain a closed aniline gas atmosphere. The probe gel was suspended at the top of the centrifuge tube to fully expose it to aniline vapor, and the change in fluorescence intensity was observed. As Figure 10 shown, with the increase in aniline concentration, the fluorescence of the TPEN gel changed from yellow-green to red.
[0054] Example 8: Application of the Tetraphenylethylene-based AIE Fluorescent Probe TPEN-loaded Film in the Detection of Liquid Aniline
[0055] A small amount of TPEN probe solution was evenly coated on a glass slide, and a TPEN solid film (c = 1×10-6 mol / L) was prepared using a spin-coating device. Subsequently, aniline solutions of different concentrations were dropped onto the glass slide loaded with the probe, and the color change was observed under a 365 nm ultraviolet lamp. As Figure 11 shown, with the increase in aniline concentration, the fluorescence of the TPEN film changed from yellow-green to red.
[0056] Example 9: Application of the Simple Device of the Tetraphenylethylene-based AIE Fluorescent Probe TPEN in the Detection of Gaseous Aniline
[0057] A simple device was made with a glass bottle and a fluorescence dish (c = 1×10-6mol / L). Aniline solutions of different concentrations were added to the fluorescence dish, the glass bottle was covered tightly, and it was slightly heated for a period of time to obtain a sealed aniline gas atmosphere. It was placed under an ultraviolet lamp for observation, and the change in its fluorescence intensity was observed. As Figure 12 shown, with the increase in aniline concentration, the fluorescence in the fluorescence dish gradually changed from yellow-green to red.
Claims
1. An aniline-specific fluorescent probe based on AIE performance, characterized in that, It has the following structural formula:
2. The preparation method of the aniline-specific fluorescence probe based on AIE performance according to claim 1, wherein, It includes the following steps: Mix compound 2 and benzothiazole-2-acetonitrile in a solvent and react for 4 hours; after the reaction, rotary evaporate the solvent to obtain a solid crude product, and obtain the probe TPEN by column chromatography; wherein, the molar ratio of compound 2 to benzothiazole-2-acetonitrile is 1:1.15; the silica gel used in column chromatography is 200-300 mesh, and the eluent is: V(ethyl acetate) / V(petroleum ether)=10 / 1; Compound 2 has the following structural formula:
3. Use of the aniline-specific fluorescent probe based on AIE performance according to claim 1 in a reagent for qualitatively and quantitatively detecting aniline.
4. Use of the aniline-specific fluorescent probe based on AIE performance according to claim 3, characterized in that, Specifically include: Dissolve the fluorescent probe TPEN in THF solvent to prepare a 1×10 -3 mol / L probe solution, then add the substance to be tested. After the reaction, fluorescence detection is carried out at 290 nm, and it is observed that the fluorescence response of the fluorescent probe TPEN to aniline can exhibit characteristic ratio-type fluorescence emission.
5. Use of the aniline-specific fluorescent probe based on AIE performance according to claim 3, characterized in that, Specifically include: Dissolve the fluorescent probe TPEN in THF to prepare a solution with a concentration of 1.0×10 -5 mol / L of the fluorescent probe TPEN, then add the sample to be tested, detect the fluorescence intensity, and quantitatively calculate the content of aniline according to the linear relationship between the fluorescence intensity and the concentration of the sample to be tested respectively.
6. The application of the aniline-specific fluorescent probe based on AIE performance according to claim 3, wherein, Gel was used to detect liquid and gaseous aniline. The specific steps were as follows: Gel beads with uniform shape were made from sodium alginate and TPEN solution, with a concentration of 1×10 -6 mol / L. They were immersed in aniline solutions with different concentrations, and the changes in fluorescence intensity were observed. When detecting gaseous aniline, the steps were as follows: The 10 mL glass bottle containing aniline solutions with different concentrations was tightly capped and slightly heated for a period of time to obtain a closed aniline gas atmosphere. The probe gel was suspended at the top of the centrifuge tube to fully expose it to aniline vapor, and the changes in fluorescence intensity were observed.
7. Use of the aniline-specific fluorescence probe based on AIE performance according to claim 3, characterized in that, Detecting liquid aniline using a thin film, the specific steps are as follows: evenly apply a small amount of TPEN probe solution on a glass slide, and use a spin coating device to make a TPEN solid film with a concentration of 1×10 -6 mol / L; subsequently, drop aniline solutions with different concentrations on the glass slide loaded with the probe, and observe the color change under a 365 nm ultraviolet lamp.
8. Use of the aniline-specific fluorescent probe based on AIE performance according to claim 3, characterized in that, The specific steps for detecting gaseous aniline are as follows: make a simple device with a glass bottle and a fluorescence dish, add aniline solutions with different concentrations into the fluorescence dish, put it into the glass bottle, tighten the cap and heat slightly to obtain a closed aniline gas atmosphere, and observe it under an ultraviolet lamp to observe the change in its fluorescence intensity.