Blue fluorescent silicon nanodot, preparation method thereof and application of blue fluorescent silicon nanodot in rapid detection of thiabendazole

Abstract

The invention discloses a blue fluorescent silicon nanodot, a preparation method thereof and application of the blue fluorescent silicon nanodot in rapid detection of thiabendazole, the method comprises the following steps: S1, adding hydroquinone into ultrapure water, then adding 3-aminopropyltrimethoxysilane, uniformly stirring, and carrying out hydrothermal reaction on the obtained mixture; and S2, cooling after the reaction is finished, purifying the product by using a silica gel chromatographic column, eluting by using an eluent, collecting the eluent, and freeze-drying to obtain the blue fluorescent silicon nanodots. The silicon nanodot provided by the invention has excellent light stability and high quantum yield, and shows a remarkable fluorescence quenching effect in the presence of thiabendazole; the method for rapidly detecting the thiabendazole is further constructed by utilizing the characteristics, has the advantages of low detection limit, accurate and reliable detection and the like, can realize rapid and reliable detection of pesticide residues, and provides an efficient and practical technical approach for food safety and quality monitoring.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nanomaterials, and particularly relates to a blue fluorescent silicon nanodot, a preparation method thereof and application thereof in rapid detection of thiabendazole. BACKGROUND

[0002] At present, the main safety hazard of the fruit and vegetable industry is the extensive use of chemical pesticides, especially benzimidazole compounds. For example, thiabendazole (TBZ) can inhibit the growth and reproduction of pathogenic fungi through various ways such as hydrogen bonding with enzymes or receptors in organisms, coordination with metal ions, or hydrophobic interaction and π-π interaction. Although TBZ has a significant fungicidal effect, it is easy to be adsorbed or enriched in agricultural products, thereby causing food pollution. Long-term intake of such residues can pose a serious threat to human health, including cancer, cardiovascular disease, fetal malformation or premature birth, etc. Therefore, it is of great significance to establish an efficient and sensitive TBZ detection technology for food safety protection.

[0003] So far, traditional analysis methods (such as gas chromatography, liquid chromatography and mass spectrometry) have been widely used in pesticide residue detection due to their high precision and accuracy. However, these techniques generally have limitations such as complex sample pretreatment, long detection period, expensive instruments and high technical requirements for operators, which are difficult to meet the needs of rapid and on-site detection. In contrast, fluorescence sensing technology based on nanomaterials is becoming an ideal alternative in the field of pesticide analysis due to its advantages such as simplicity, rapidness, high sensitivity and high selectivity. However, there is currently a lack of reliable solutions for detecting thiabendazole using the above nanomaterials. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a blue fluorescent silicon nanodot, a preparation method thereof and application thereof in rapid detection of thiabendazole, in view of the deficiencies in the prior art.

[0005] To solve the above technical problems, the technical solution adopted by the present application is as follows: In a first aspect, the present application provides a preparation method of a blue fluorescent silicon nanodot, comprising the following steps: S1. Hydrothermal reaction of hydroquinone and 3-aminopropyltrimethoxysilane in ultrapure water; S2. Purification of the product with a silica gel chromatography column after cooling, elution with an eluent, collection of the eluent, and freeze-drying to obtain the blue fluorescent silicon nanodot.

[0006] Preferably, the hydrothermal reaction temperature in step S1 is 160-200℃, and the reaction time is 4-16 hours.

[0007] Preferably, the hydrothermal reaction temperature in step S1 is 180℃, and the reaction time is 8 hours.

[0008] Preferably, the eluent is a mixture of dichloromethane and methanol.

[0009] Preferably, the volume ratio of dichloromethane and methanol in the eluent is 5-20:1.

[0010] Preferably, the method for preparing the blue fluorescent silicon nanodots comprises the following steps: S1, 0.1-0.4 g of hydroquinone is added to 10-40 mL of ultrapure water for dissolution, and then 0.5-2 ml of 3-aminopropyltrimethoxysilane is added and stirred uniformly, and the obtained mixture is transferred to a reaction kettle for reaction at 160-200℃ for 4-16 hours; S2, after the reaction is completed, the product is cooled to room temperature, the precipitate is discarded after centrifugation, and then the product is purified by a silica gel chromatographic column, eluted by an eluent, the eluent is composed of dichloromethane and methanol at a volume ratio of 5-20:1, the eluent is collected, and then freeze-drying is performed to obtain the blue fluorescent silicon nanodots.

[0011] Preferably, the method for preparing the blue fluorescent silicon nanodots comprises the following steps: S1, 0.2 g of hydroquinone is added to 20 mL of ultrapure water for dissolution, and then 1.0 ml of 3-aminopropyltrimethoxysilane is added and stirred uniformly, and the obtained mixture is transferred to a reaction kettle for reaction at 180℃ for 8 hours; S2, after the reaction is completed, the product is cooled to room temperature, the precipitate is discarded after centrifugation, and then the product is purified by a silica gel chromatographic column, eluted by an eluent, the eluent is composed of dichloromethane and methanol at a volume ratio of 10:1, the eluent is collected, and then freeze-drying is performed to obtain the blue fluorescent silicon nanodots.

[0012] In a second aspect of the present application, a blue fluorescent silicon nanodot is provided, which is prepared by the method as described above.

[0013] In a third aspect of the present application, the application of the blue fluorescent silicon nanodot as described above in detecting thiabendazole is provided.

[0014] Preferably, the application method is as follows: The blue fluorescent silicon nanodots are configured into a dispersion liquid, and then mixed with a solution to be detected containing thiabendazole, the fluorescence intensity of the emission light of the product at 450 nm under excitation light at 300 nm is detected, and the concentration of thiabendazole in the solution to be detected is obtained according to the fluorescence intensity of the emission light; wherein the concentration of thiabendazole is negatively correlated with the fluorescence intensity of the emission light.

[0015] The present application has the following beneficial effects: The application provides a silicon nanodot with high light stability and strong blue light emitting characteristics, the silicon nanodot has excellent light stability and high quantum yield, and presents a significant fluorescence quenching effect in the presence of thiabendazole; the application further constructs a rapid thiabendazole detection method by using the characteristics, has the advantages of low detection limit, accurate and reliable detection, and can realize rapid and reliable detection of pesticide residues, and provides an efficient and practical technical approach for food safety and quality monitoring. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 FT-IR and XPS characterization results of the blue fluorescent silicon nanodots prepared in the application; Figure 2 Optical property and light stability test results of the blue fluorescent silicon nanodots prepared in the application; Figure 3 Feasibility test results and quenching mechanism diagram of the blue fluorescent silicon nanodots prepared in the application for detecting thiabendazole. DETAILED DESCRIPTION

[0017] The application will be further described in detail below with reference to the examples, so that those skilled in the art can implement the application according to the description.

[0018] It should be understood that the terms such as "have", "contain" and "include" used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0019] The test methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples can be obtained commercially unless otherwise specified. The specific conditions are not specified in the following examples, and the conventional conditions or the conditions recommended by the manufacturer are used. The reagents or instruments used are not specified by the manufacturer, and are conventional products that can be obtained by commercial purchase.

[0020] Example 1 A blue fluorescent silicon nanodot, the preparation method thereof comprises the following steps: S1, 0.2g of hydroquinone is taken into a beaker, dissolved in 20mL of ultrapure water, then 1.0ml of 3-aminopropyltrimethoxysilane is added, stirred uniformly, and the obtained mixture is transferred to a reaction kettle, and reacted at 180℃ in a dry box for 8 hours; S2, after the reaction is completed, the product is cooled to room temperature, centrifuged (8000 revolutions per minute, 5 minutes) to remove the precipitated impurities, and then the remaining centrifuged liquid is purified by a silica gel chromatography column, eluted with an eluent, the eluent is composed of dichloromethane and methanol at a volume ratio of 10:1, the eluent is collected, and freeze-dried to obtain blue fluorescent silicon nanodots (referred to as silicon nanodots) denoted as SiNDs.

[0021] Example 2 The application of a blue fluorescent silicon nanodot in detecting thiabendazole, the application method is: The blue fluorescent silicon nanodot prepared in Example 1 is configured into a dispersion liquid, then mixed with a to-be-detected solution containing thiabendazole, the fluorescence intensity of the emission light at 450 nm of the product under 300 nm excitation light is detected, and the concentration of thiabendazole in the to-be-detected solution is analyzed according to the fluorescence intensity of the emission light; wherein the concentration of thiabendazole is negatively correlated with the fluorescence intensity of the emission light.

[0022] Performance characterization and testing (1) Structure and fluorescence properties of silicon nanodots The FT-IR and XPS characterization results of SiNDs are shown in Figure 1 A and 1B, the appearance of silicon element characteristic peaks and silicon-based functional groups proves the successful synthesis of silicon nanodots.

[0023] The optical property and light stability test results are shown in Figure 2 , Figure 2 A, the synthesized silicon nanodots have a maximum excitation peak at 300 nm, and the maximum emission peak is at 450 nm, showing typical blue fluorescence characteristics. After 10 hours of continuous natural light irradiation, the fluorescence intensity remains above 93% of the initial value (Figure 2B), indicating that the material has excellent light stability and can maintain high signal reliability in complex detection environments.

[0024] (2) Silicon nanodots for thiabendazole detection Specifically, different concentrations (0-150 μM) of TBZ (thiabendazole) solution were added to 1 mL of silicon nanodot solution with a concentration of 0.2 mg·mL⁻¹ (solvent is deionized water), and after standing for 1 min, the fluorescence intensity of the emission light at 450 nm was recorded with 300 nm as the excitation wavelength. As can be seen from Figures 3A-B, as the concentration of TBZ increases, the fluorescence intensity of the silicon nanodots gradually decreases, and there is a good linear correlation between the fluorescence signal and the concentration of TBZ, and the standard curve is shown in Figure 3 B. According to the calculation, the detection limit of silicon nanodots for TBZ is 15.3 nM, indicating that it has high detection sensitivity.

[0025] Based on this, a quantitative method for detecting thiabendazole (TBZ) using fluorescent silicon nanodots can be established: The blue fluorescent silicon nanodot is configured into a dispersion liquid, then mixed with a to-be-detected solution containing thiabendazole, the fluorescence intensity of the emission light at 450 nm of the product under 300 nm excitation light is detected, and the concentration of thiabendazole in the to-be-detected solution is analyzed according to the fluorescence intensity of the emission light.

[0026] Further analysis found that, as shown in Fig. 3B, TBZ has a strong absorption band in the range of 300-340 nm, thereby weakening the excitation energy absorption of SiNDs (fluorescent silicon nanodots) at 300 nm, indicating that the fluorescence quenching is mainly caused by the inner filter effect. In addition, the fluorescence lifetime of SiNDs changes slightly from 3.98 ns to 3.85 ns (Fig. 3C), and no significant change is observed (Fig. 3D), further confirming that the quenching process is not caused by dynamic quenching. Figure 3 Figure 3

[0027] In summary, the present application successfully prepared a kind of silicon nanodots with high light stability and strong blue luminescence characteristics, and using the fluorescence quenching effect of thiabendazole, the specific and high sensitive detection of TBZ can be realized; This strategy provides a simple, rapid and efficient detection way for pesticide residue analysis and food safety monitoring.

[0028] Although the embodiments of the present application have been disclosed as above, it is not limited to the application listed in the specification and embodiments, and can be fully applied to various fields suitable for the present application. For those skilled in the art, other modifications can be easily realized, and therefore the present application is not limited to specific details without departing from the general concept defined by the claims and equivalent scope.​​

Claims

1. A method for preparing blue fluorescent silicon nanodots, characterized in that, Includes the following steps: S1. Add hydroquinone to ultrapure water, then add 3-aminopropyltrimethoxysilane, stir until homogeneous, and carry out hydrothermal reaction of the resulting mixture. S2. After the reaction is complete, the product is cooled and purified by silica gel chromatography. The product is eluted with eluent, collected, and freeze-dried to obtain blue fluorescent silicon nanodots.

2. The method for preparing blue fluorescent silicon nanodots according to claim 1, characterized in that, The hydrothermal reaction temperature in step S1 is 160-200℃ and the reaction time is 4-16 hours.

3. The method for preparing blue fluorescent silicon nanodots according to claim 2, characterized in that, The hydrothermal reaction temperature in step S1 is 180℃ and the reaction time is 8 hours.

4. The method for preparing blue fluorescent silicon nanodots according to claim 1, characterized in that, The eluent is a mixture of dichloromethane and methanol.

5. The method for preparing blue fluorescent silicon nanodots according to claim 4, characterized in that, The volume ratio of dichloromethane to methanol in the eluent is 5~20:

1.

6. The method for preparing blue fluorescent silicon nanodots according to claim 1, characterized in that, Includes the following steps: S1. Dissolve 0.1-0.4g of hydroquinone in 10-40mL of ultrapure water, then add 0.5-2ml of 3-aminopropyltrimethoxysilane, stir until homogeneous, transfer the resulting mixture to a reaction vessel, and react at 160-200℃ for 4-16 hours. S2. After the reaction is complete, cool to room temperature, centrifuge the product to discard the precipitate, and purify it with a silica gel chromatography column. Elute with a dichloromethane and methanol in a volume ratio of 5-20:

1. Collect the eluent, freeze-dry it, and obtain blue fluorescent silicon nanodots.

7. The method for preparing blue fluorescent silicon nanodots according to claim 6, characterized in that, Includes the following steps: S1. Dissolve 0.2g hydroquinone in 20mL of ultrapure water, then add 1.0mL of 3-aminopropyltrimethoxysilane, stir until homogeneous, transfer the resulting mixture to a reaction vessel, and react at 180℃ for 8 hours. S2. After the reaction is complete, cool to room temperature, centrifuge the product to discard the precipitate, and then purify it with a silica gel chromatography column. Elute with a solution of dichloromethane and methanol in a volume ratio of 10:

1. Collect the eluent, freeze-dry it, and obtain blue fluorescent silicon nanodots.

8. A blue fluorescent silicon nanodot, characterized in that, It is prepared by the method described in any one of claims 1-7.

9. The application of the blue fluorescent silicon nanodots as described in claim 8 in the detection of thiabendazole.

10. The application according to claim 9, characterized in that, The application method is as follows: Blue fluorescent silicon nanodots were prepared into a dispersion and then mixed with a test solution containing thiabendazole. The fluorescence intensity of the emitted light of the product at 450 nm under 300 nm excitation light was detected. The concentration of thiabendazole in the test solution was obtained by analyzing the fluorescence intensity of the emitted light. The concentration of thiabendazole was negatively correlated with the fluorescence intensity of the emitted light.

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