Fluorescent microsphere as well as preparation method and application thereof

Abstract

The invention provides fluorescent microspheres as well as a preparation method and application thereof, and belongs to the technical field of fluorescent probe materials. The preparation method of the fluorescent microspheres comprises the following steps: dissolving N, N '-((2-(9-carbazolyl))-1, 3-phenyl) bis (methylene) bisacrylamide and an initiator in a mixed solvent, and carrying out polymerization reaction under the protection of a nitrogen atmosphere to obtain the fluorescent microspheres. According to the present invention, the single monomer is subjected to self-polymerization to form the ball in one step, the cross-linking agent or the template is not required, the preparation method is simple and controllable, the detection limit of the 3, 5-dinitrobenzoic acid is as low as 0.096 [mu] M, and the sensitivity is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fluorescent probe materials, in particular to a fluorescent microsphere and a preparation method and application thereof. BACKGROUND

[0002] Nitroaromatic compounds (such as nitrobenzoic acid, dinitrobenzene derivatives) and metal ions (such as Fe 3+ ) are important sources of environmental pollution, and their rapid and sensitive detection is crucial for ecological safety and human health. However, the commonly used fluorescent probe materials (such as quantum dots, metal-organic frameworks) have many problems. For example, the synthesis is complex: it requires multi-component copolymerization, template assistance or surface modification, which is tedious and costly; it is not recyclable: most probes are disposable, causing resource waste; the sensitivity is insufficient, with a high detection limit; and the selectivity is poor: additional functional groups need to be introduced to improve the recognition ability.

[0003] Patent CN116589674A discloses a functionalized carbon dioxide-based polycarbonate, which introduces fluorescein during polymerization to copolymerize and form a probe material with fluorescent properties. However, the synthesis steps are complex, high-temperature and high-pressure reaction kettles are used multiple times during the synthesis process, the selectivity is poor, and in addition to Fe 3+ , Al 3+ can also quench the fluorescence of the probe. Patent CN119176949A discloses a covalent organic polymer fluorescent probe and a method for detecting -OH-containing nitro explosives, which constructs a Zn(II)-based coordination polymer through a solvothermal method, and the detection limit for 2,4,6-trinitrophenol is as low as LOD = 0.164 μmol·L -1 , but it requires a Ni(0) catalyst and a complex synthesis method, limiting its application. Patent CN202110070820.8 discloses a supramolecular fluorescent compound and its preparation method and application. The compound is assembled by intermolecular non-covalent interactions (such as hydrogen bonds, van der Waals forces, π-π stacking, etc.), and can detect Fe 3+ and nitroaromatic compounds, but its synthesis method involves stirring at room temperature and then heating to 120℃, which has certain deficiencies in the simplicity of the synthesis process. Patent CN202411474370.9 discloses a covalent organic polymer fluorescent probe and a method for detecting -OH-containing nitro explosives. The probe is constructed by strong covalent bonds to form a material with a regular network structure, and has specific structural design and functional groups for -OH-containing nitro explosives. However, the synthesis of general covalent organic polymers requires precise control of reaction conditions, such as monomer ratio, reaction temperature, and time, to form a regular network structure, making the synthesis process more complex.

[0004] Based on this, a kind of fluorescence microspheres is provided, which is formed by single functional monomer (PCAM) self-polymerization, without crosslinking agent or template, synthesis process is simple and controllable, and surface is enriched with carbazole group and amide bond, can efficiently capture Fe 3+ And fluorescence microspheres of nitro compound have important significance. SUMMARY

[0005] The present application aims to provide a kind of fluorescence microspheres and its preparation method and application, to solve the technical problems of poor selectivity, low sensitivity, complex preparation method, need to introduce other components copolymerization, high cost in prior art fluorescence microsphere probe.

[0006] To achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0007] The present application provides a kind of fluorescence microspheres, the fluorescence microspheres have the following structural formula:

[0008]

[0009] The preparation method of the fluorescence microspheres of the present application comprises the following steps:

[0010] N,N'-((2-(9-carbazolyl))-1,3-phenyl) bis(methylene) bisacrylamide and initiator are dissolved in mixed solvent, and polymerization reaction is carried out under the protection of nitrogen atmosphere, to obtain fluorescence microspheres;

[0011] The particle size of the fluorescence microspheres is 1-2.5 μm.

[0012] Further, the amount ratio of N,N'-((2-(9-carbazolyl))-1,3-phenyl) bis(methylene) bisacrylamide, initiator and mixed solvent is 1-10 g:0.02-0.5 g:25-250 mL.

[0013] Further, the initiator includes azobisisobutyronitrile.

[0014] The mixed solvent includes two of ethanol, acetonitrile, isopropanol, N,N-dimethylformamide and N,N-dimethylacetamide.

[0015] The volume ratio of the two solvents in the mixed solvent is 4-10:4-10.

[0016] Further, the polymerization reaction is carried out under stirring, the stirring speed is 500-1000 rpm, the polymerization reaction temperature is 70-90 DEG C, and the polymerization reaction time is 2-24 h.

[0017] The present application also provides a kind of fluorescence microspheres in the preparation of detecting Fe 3+The application of the fluorescent microspheres in the material of nitroaromatic compounds, the fluorescent microspheres are dispersed in a solvent to obtain a fluorescent microsphere probe;

[0018] The fluorescent microsphere probe is used for selectively detecting Fe 3+ or nitroaromatic compounds.

[0019] Further, the solvent includes a methanol solution and / or an N,N-dimethylformamide solution;

[0020] The volume concentration of the methanol solution is 60-100%.

[0021] The volume concentration of the N,N-dimethylformamide solution is 0-40%.

[0022] Further, the mass concentration of the fluorescent microspheres is 0.05-0.25 mg / mL.

[0023] Further, the nitroaromatic compounds include one or more of 3,5-dinitrobenzoic acid, 3-nitrobenzoic acid, 2-nitrobenzoic acid, 1,5-difluoro-2,6-dinitrobenzene and 2,3,4-trifluoronitrobenzene.

[0024] The beneficial effects of the present application are as follows:

[0025] 1) The present application uses a unique monomer self-polymerization ball technology, without the aid of a crosslinking agent or a template, thereby simplifying the multi-component regulation complexity in the traditional nanomaterial preparation process, reducing the reaction steps to a single operation, and the product yield is more than 85%, which significantly improves the synthesis efficiency and reduces the raw material cost;

[0026] 2) The fluorescent microspheres prepared by the present application technology as a probe, the detection limit of 3,5-dinitrobenzoic acid reaches 0.096 μM, which greatly improves the sensitivity of detection, and is especially suitable for trace detection of environmental pollutants; in the selective experiment, the recognition of Fe 3+ is not interfered by Ca 2+ , Mg 2+ and other metal ions, and in the presence of coexisting ions, it still maintains a high specific response;

[0027] 3) The fluorescent microspheres prepared by the present application through an EDTA / acetone double-solvent regeneration system, after 5 cycles of use, the retention rates of the fluorescence intensity are as high as 87% and 77% respectively, showing good recyclability. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The infrared spectrum of the fluorescent microspheres prepared in Example 1;

[0029] Figure 2SEM image of the fluorescent microspheres prepared for Example 1;

[0030] Figure 3 Graph of the selectivity test of the fluorescent microsphere probe prepared for Example 1;

[0031] Figure 4 Graph of the change in the fluorescence spectrum of the fluorescent microsphere probe prepared for Example 1 as the concentration of Fe 3+ increased;

[0032] Figure 5 Graph of the linear fitting between the fluorescence intensity at 367 nm of the fluorescent microsphere probe prepared for Example 1 and the concentration of Fe 3+ ;

[0033] Figure 6 Graph of the change in the fluorescence intensity of the fluorescent microsphere probe prepared for Example 1 after undergoing 5 cycles of Fe 3+ detection;

[0034] Figure 7 Graph of the change in the fluorescence spectrum of the fluorescent microsphere probe prepared for Example 1 as the concentration of 3,5-DNBA increased;

[0035] Figure 8 Graph of the linear fitting between the fluorescence intensity at 367 nm of the fluorescent microsphere probe prepared for Example 1 and the concentration of 3,5-DNBA;

[0036] Figure 9 Graph of the change in the fluorescence spectrum of the fluorescent microsphere probe prepared for Example 1 as the concentration of 2-NBA increased;

[0037] Figure 10 Graph of the linear fitting between the fluorescence intensity at 367 nm of the fluorescent microsphere probe prepared for Example 1 and the concentration of 2-NBA;

[0038] Figure 11 Graph of the change in the fluorescence spectrum of the fluorescent microsphere probe prepared for Example 1 as the concentration of 3-NBA increased;

[0039] Figure 12 Graph of the linear fitting between the fluorescence intensity at 367 nm of the fluorescent microsphere probe prepared for Example 1 and the concentration of 3-NBA;

[0040] Figure 13 Graph of the change in the fluorescence spectrum of the fluorescent microsphere probe prepared for Example 1 as the concentration of DFDNB increased;

[0041] Figure 14A linear fitting curve plot between the fluorescence intensity at 367 nm of the fluorescent microsphere probe prepared for Example 1 and the DFDNB concentration;

[0042] Figure 15 A curve plot of the fluorescence spectrum of the fluorescent microsphere probe prepared for Example 1 changing with the increase of the FTRBN concentration;

[0043] Figure 16 A linear fitting curve plot between the fluorescence intensity at 367 nm of the fluorescent microsphere probe prepared for Example 1 and the FTRBN concentration;

[0044] Figure 17 A plot of the change of the fluorescence intensity of the fluorescent microsphere probe prepared for Example 1 after detecting the nitroaromatic compound for 5 cycles. DETAILED DESCRIPTION

[0045] The present application provides a fluorescent microsphere, which has the following structural formula:

[0046]

[0047] The present application provides a preparation method of the fluorescent microsphere, which comprises the following steps:

[0048] N,N'-((2-(9-carbazolyl))-1,3-phenyl) bis(methylene) bisacrylamide and an initiator are dissolved in a mixed solvent, and a polymerization reaction is carried out under the protection of a nitrogen atmosphere to obtain the fluorescent microsphere.

[0049] In the present application, the particle size of the fluorescent microsphere is 1-2.5 μm, preferably 1.2-2.2 μm, and further preferably 1.5-2.0 μm.

[0050] In the present application, the use ratio of the N,N'-((2-(9-carbazolyl))-1,3-phenyl) bis(methylene) bisacrylamide, the initiator and the mixed solvent is 1-10 g:0.02-0.5 g:25-250 mL, preferably 2-9 g:0.05-0.45 g:50-225 mL, and further preferably 3-8 g:0.1-0.4 g:75-200 mL.

[0051] In the present application, the initiator is preferably azobisisobutyronitrile.

[0052] In the present application, the mixed solvent comprises two of ethanol, acetonitrile, isopropanol, N,N-dimethylformamide and N,N-dimethylacetamide, preferably two of ethanol, isopropanol, N,N-dimethylformamide and N,N-dimethylacetamide, and further preferably ethanol and N,N-dimethylacetamide.

[0053] The volume ratio of the two solvents in the mixed solvent is 4-10:4-10, preferably 4.5-9.5:4.5-9.5, and more preferably 5-9:5-9.

[0054] In the present application, the polymerization reaction is carried out under stirring at a stirring speed of 500-1000 rpm, preferably 550-950 rpm, and more preferably 600-900 rpm; the temperature of the polymerization reaction is 70-90℃, preferably 75-85℃, and more preferably 80℃; and the time of the polymerization reaction is 2-24 h, preferably 5-20 h, and more preferably 8-16 h.

[0055] The present application also provides a fluorescent microsphere for preparing a material for detecting Fe 3+ or a nitro aromatic compound, wherein the fluorescent microsphere is dispersed in a solvent to obtain a fluorescent microsphere probe.

[0056] The fluorescent microsphere probe is used for selectively detecting Fe 3+ or a nitro aromatic compound.

[0057] In the present application, the solvent includes a methanol solution and / or an N,N-dimethylformamide solution, and preferably a methanol solution.

[0058] The volume concentration of the methanol solution is 60-100%, preferably 70-90%, and more preferably 80%.

[0059] The volume concentration of the N,N-dimethylformamide solution is 0-40%, preferably 10-30%, and more preferably 20%.

[0060] In the present application, the mass concentration of the fluorescent microsphere is 0.05-0.25 mg / mL, preferably 0.08-0.22 mg / mL, and more preferably 0.1-0.2 mg / mL.

[0061] In the present application, the nitro aromatic compound includes one or more of 3,5-dinitrobenzoic acid (3,5-DNBA), 3-nitrobenzoic acid (3-NBA), 2-nitrobenzoic acid (2-NBA), 1,5-difluoro-2,6-dinitrobenzene (DFDNB), and 2,3,4-trifluoronitrobenzene (FTRBN).

[0062] In the present application, when selectively detecting, the excitation wavelength is 240-300 nm, preferably 245-295 nm, and more preferably 250-290 nm; and the emission wavelength is 330-500 nm, preferably 335-450 nm, and more preferably 340-400 nm.

[0063] In the present application, the recovery method of the fluorescent microsphere probe is: after detection, sequentially recovering the fluorescent microspheres through centrifugation and ultrasonic treatment, Fe 3+ After being desorbed by ethylenediaminetetraacetic acid, the nitroaromatic compound is repeatedly used after being washed by acetone.

[0064] In the present application, the rotation speed of the centrifugation is 6000-10000 rpm, preferably 6500-9500 rpm, and further preferably 7000-9000 rpm; the centrifugation time is 2-10 min, preferably 3-9 min, and further preferably 4-8 min; and the ultrasonic treatment time is 2-10 min, preferably 3-9 min, and further preferably 4-8 min.

[0065] In the present application, Fe 3+ The detection limits of 3,5-dinitrobenzoic acid (3,5-DNBA), 3-nitrobenzoic acid (3-NBA), 2-nitrobenzoic acid (2-NBA), 1,5-difluoro-2,6-dinitrobenzene (DFDNB), and 2,3,4-trifluoronitrobenzene (FTRBN) are 0.84 μM, 0.096 μM, 0.52 μM, 0.46 μM, 0.38 μM, and 0.37 μM, respectively.

[0066] The technical solutions provided by the present application will be described in detail below in conjunction with the examples, but they should not be understood as limiting the scope of protection of the present application.

[0067] Example 1

[0068] 2 g of N,N'-((2-(9-carbazolyl))-1,3-phenyl) bis(methylene) bisacrylamide monomer and 0.1 g of azobisisobutyronitrile were added to a 50 mL mixed solution of ethanol and N,N-dimethylacetamide in a volume ratio of 6:4, and polymerization was carried out at 85°C under nitrogen atmosphere protection at a rotation speed of 800 rpm. After 12 h, the reaction was completed, the reaction liquid was centrifuged at a rotation speed of 10000 rpm for 15 min, washed with ethanol for 3 times, and dried under vacuum at 60°C. After drying, the fluorescent microspheres were obtained. The prepared fluorescent microspheres were characterized, and the results are shown in Figures 1-2

[0069] The fluorescent microspheres prepared in Example 1 were subjected to a selective experiment. The method was as follows: the prepared fluorescent microspheres were dispersed in a methanol solution in a volume ratio of 8:2, and the mass concentration of the fluorescent microspheres was 2 mg / mL, to obtain a fluorescent microsphere probe; then 200 μL of a metal ion solution with a concentration of 10 -2 M was added, and the metal ions were Li + , Na + , K + , Ag + , and Ca​2+ , Ni 2+ , Fe 2+ , Mn 2+ , Mg 2+ , Zn 2+ , Co 2+ , Pb 2+ , Hg 2+ , Al 3+ , Cr 3+ , Fe 3+ , Y 3+ , 3,5-DNBA, 3-NBA, 2-NBA, DFDNB, FTRBN, respectively. The fluorescence intensity of the fluorescent microsphere probe was observed, and the results of the selective test are shown in Table 1. Figure 3

[0070] The fluorescent microsphere probe prepared in Example 1 was subjected to Fe 3+ detection limit and cycle performance test. The prepared fluorescent microspheres were dispersed in a methanol solution with a volume ratio of 8:2, and the mass concentration of the fluorescent microspheres was 2 mg / mL to obtain a fluorescent microsphere probe. Then, 200 μL of a Fe -2 solution with a concentration of 10 3+ M was added. The test results of the detection limit are shown in Table 2. Figures 4-5 After adding 10 mM EDTA solution and ultrasonic treatment for 10 min, centrifugation was performed, and cycle performance test was carried out. The test results are shown in Table 3. Figure 6

[0071] As can be seen from Table 2, the emission peak intensity at 367 nm linearly decreased with the increase of Fe + concentration. According to the formula LOD = 3σ / K, the detection limit was calculated to be 0.84 μM. Figures 4-5 As can be seen from Table 3, the fluorescence of the fluorescent microsphere probe recovered by 87% after 5 cycles of detection.

[0072] Figure 6 The fluorescent microsphere probe prepared in Example 1 was subjected to nitroaromatic compound detection limit and cycle performance test. The prepared fluorescent microspheres were dispersed in a methanol solution with a volume ratio of 8:2, and the mass concentration of the fluorescent microspheres was 2 mg / mL to obtain a fluorescent microsphere probe. Then, 200 μL of 3,5-DNBA solution, 3-NBA solution, 2-NBA solution, DFDNB solution, and FTRBN solution with a concentration of 10 -2 M was added. The test results of the detection limit are shown in Table 4.

[0073] Figures 7-16 ​​​​The results of the cycle performance test are shown in Table 1. As an example of 3,5-DNBA, after adding 10 mM acetone / methanol / acetonitrile solution and ultrasonic treatment for 10 min, centrifugation was performed, and the cycle performance test was carried out, and the test results are shown in Table 1. Figure 17 As shown in Table 1.

[0074] As shown in Table 1. Figures 7-16 It can be seen that the detection limit calculated according to the formula LOD = 3σ / K is 0.096 μM, 0.52 μM, 0.46 μM, 0.38 μM, and 0.37 μM, respectively.

[0075] As shown in Table 1. Figure 17 It can be seen that the fluorescence of the fluorescent microsphere probe recovers 77% after 5 cycles of detection.

[0076] Example 2

[0077] Compared with Example 1, the difference is that in Example 2, the volume ratio of ethanol to N,N-dimethylacetamide is 7:3.

[0078] Example 3

[0079] Compared with Example 1, the difference is that in Example 3, the temperature of the polymerization reaction is 80℃.

[0080] Example 4

[0081] Compared with Example 1, the difference is that in Example 4, the mass concentration of the fluorescent microspheres is 0.15 mg / mL.

[0082] It can be seen from the above examples that the present application provides a fluorescent microsphere probe and a preparation method and application thereof. The preparation method of the fluorescent microspheres of the present application is as follows: N,N'-((2-(9-carbazolyl))-1,3-phenyl) bis(methylene) bisacrylamide and an initiator are dissolved in a mixed solvent, and a polymerization reaction is carried out under the protection of a nitrogen atmosphere to obtain fluorescent microspheres. The present application forms a ball in one step by self-polymerization of a single monomer without the need for a crosslinking agent or a template, and the preparation method is simple and controllable. The detection limit of 3,5-dinitrobenzoic acid is as low as 0.096 μM, and the present application has high sensitivity.

[0083] The above description is only the preferred embodiments of the present application, and it should be pointed out that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. Fluorescent microspheres characterized in that, The fluorescent microspheres have the following structural formula:

2. A method of preparing the fluorescent microspheres of claim 1, characterized in that, The method comprises the following steps: N,N'-((2-(9-carbazolyl))-1,3-phenyl) bis(methylene) bisacrylamide and an initiator are dissolved in a mixed solvent, and a polymerization reaction is carried out under the protection of a nitrogen atmosphere to obtain the fluorescent microspheres. The particle size of the fluorescent microspheres is 1-2.5 microns.

3. The method for preparing fluorescent microspheres according to claim 2, characterized in that, The use ratio of the N,N'-((2-(9-carbazolyl))-1,3-phenyl) bis(methylene) bisacrylamide, the initiator and the mixed solvent is 1-10 g:0.02-0.5 g:25-250 mL.

4. The method for preparing fluorescent microspheres according to claim 2 or 3, characterized in that, The initiator comprises azobisisobutyronitrile. The mixed solvent comprises two of ethanol, acetonitrile, isopropyl alcohol, N,N-dimethylformamide and N,N-dimethylacetamide. The volume ratio of the two solvents in the mixed solvent is 4-10:4-10.

5. The method for preparing fluorescent microspheres according to claim 4, characterized in that, The polymerization reaction is carried out under stirring, the stirring speed is 500-1000 rpm, the polymerization reaction temperature is 70-90 DEG C, and the polymerization reaction time is 2-24 hours.

6. Use of the fluorescent microspheres according to claim 1 for the preparation of a material for the detection of Fe 3+ or nitroaromatic compounds, characterized in that, The fluorescent microspheres are dispersed in a solvent to obtain a fluorescent microsphere probe. The fluorescent microsphere probe is used for selectively detecting Fe 3+ or nitroaromatic compounds.

7. Use according to claim 6, characterized in that, The solvent comprises a methanol solution and / or an N,N-dimethylformamide solution. The volume concentration of the methanol solution is 60-100%. The volume concentration of the N,N-dimethylformamide solution is 0-40%.

8. Use according to claim 6 or 7, characterized in that, The mass concentration of the fluorescent microspheres is 0.05-0.25 mg / mL.

9. Use according to claim 8, characterized in that, The nitroaromatic compound comprises one or more of 3,5-dinitrobenzoic acid, 3-nitrobenzoic acid, 2-nitrobenzoic acid, 1,5-difluoro-2,6-dinitrobenzene and 2,3,4-trifluoronitrobenzene.

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