A dual-mode emission boron-doped silane functionalized carbon dot and its preparation method and application

Abstract

The present invention discloses a kind of dual-mode emission boron-doped silane functionalized carbon dot and its preparation method and application, relate to the field of food safety research. The preparation method comprises the following steps: nitrogen source material, 3-aminopropyl triethoxysilane and carbon source material are mixed and dissolved, heated for reaction, cooled and dialyzed to obtain silane functionalized carbon dot; boric acid, rhodamine B and water are added to the silane functionalized carbon dot obtained in step (1), heated for reaction, cooled and dried; the nitrogen source material is m-phenylenediamine; the carbon source material, nitrogen source material and 3-aminopropyl triethoxysilane molar ratio described in step (1) are (1.5-2): 1: 1.5. The boron-doped silane functionalized carbon dot of the present invention has good stability, fluorescence and phosphorescence dual emission signals and raw materials are easy to obtain, strong stability, and has great application potential in the field of food safety detection.

Description

Technical Field

[0001] The present invention relates to the technical field of food safety detection, and in particular to a dual-mode emission boron-doped silane functionalized carbon dot and a preparation method and application thereof. Background Art

[0002] Carbon dots, a novel carbon nanomaterial, offer low cost, simple preparation, low toxicity, and excellent optical properties. These attributes hold great potential for application in optical sensing. However, most carbon dots used in multichannel detection platforms rely on single-wavelength fluorescence emission, a drawback in practical applications. These features are susceptible to interference from biological autofluorescence and scattered light from environmental samples, thus compromising detection accuracy and sensitivity.

[0003] Research on material properties has revealed that embedding carbon dots in specific matrices can further optimize their performance. For example, embedding silane-functionalized carbon dots in a boric acid matrix not only provides a stable environment for the carbon dots but also potentially modifies their optical properties, enabling regulation of their fluorescence and phosphorescence properties. In the field of chemical detection technology, materials based on fluorescence and phosphorescence offer advantages such as high sensitivity and selectivity in analytical detection. Using a ratiometric method, which utilizes dual signal readings at the two emission wavelengths of carbon dots, can reduce background interference, but the technology currently requires improvement.

[0004] Research has shown that introducing an energy acceptor, such as rhodamine B, into this composite material system can create an effective energy transfer system. Based on the principle of fluorescence resonance energy transfer, efficient energy transfer is achieved when the emission spectrum of the donor and the absorption spectrum of the acceptor have sufficient spectral overlap, and the distance between the donor and the acceptor is within a certain range, typically less than 10 nm. This energy transfer process can influence the material's fluorescence and phosphorescence emission properties, providing a theoretical basis for the construction of a dual-signal ratiometric detection system.

[0005] Chinese patent CN114644924A discloses a green synthesis method for a novel biomass carbon dot and its application in pesticide detection. Using orange peel and o-phenylenediamine as raw materials, the patent rapidly synthesizes nitrogen-doped blue-light-emitting carbon dots (N-CDs) via a one-step microwave method. Gold nanoparticles are used as light absorbers to quench the fluorescence of the N-CDs through the inner filter effect. The fluorescence of the N-CDs is restored by the Au-S bond between the sulfur-containing pesticide thiram and the gold nanoparticles, establishing a method for rapid detection of thiram pesticide residues. However, the method only produces fluorescence, not phosphorescence, resulting in a single signal. Furthermore, the selectivity and anti-interference ability of the carbon dots have not been studied.

[0006] An existing paper (doi.org / 10.1016 / j.snb.2021.130898) describes a multi-stage fluorescent biosensor based on boric acid embedded in carbon dots for detecting intracellular and serum glucose. Developed by dispersing rhodamine B carbon dots (R-CDs) in a boric acid (BA) matrix, this paper can serve as a simple, inexpensive visual detector for intracellular and serum glucose concentrations. However, it only exhibits fluorescence, not phosphorescence, resulting in a single signal. Furthermore, it is not targeted at food safety testing, and the selectivity and anti-interference ability of the carbon dots have not been studied.

[0007] Traditional methods for detecting thiram, such as gas chromatography (GC), high-performance liquid chromatography (HPLC), and mass spectrometry (MS), while highly sensitive, are complex, time-consuming, and costly. Therefore, there is a need to develop a rapid, sensitive, and highly selective thiram detection method that meets practical testing needs and is of great significance in areas such as food safety testing. Summary of the Invention

[0008] In response to the problems in the prior art, the present invention provides a dual-mode emission boron-doped silane functionalized carbon dot and its preparation method and application. The raw materials of the boron-doped silane functionalized carbon dots with dual emission of fluorescence and phosphorescence are easy to obtain, have strong stability, and have dual emission peaks of fluorescence and phosphorescence signals, which effectively solves the problem of single signal of traditional optical sensing materials and has great application potential in the field of food safety detection.

[0009] To achieve the above objectives, the technical solutions adopted by the present invention include:

[0010] In a first aspect, the present invention provides a method for preparing boron-doped silane-functionalized carbon dots with dual-signal emission of fluorescence and phosphorescence, comprising the following steps:

[0011] (1) mixing and dissolving a nitrogen source material, 3-aminopropyltriethoxysilane, and citric acid, heating for reaction, cooling, and dialyzing to obtain silane-functionalized carbon dots;

[0012] (2) adding boric acid, rhodamine B and water to the silane-functionalized carbon dots obtained in step (1), heating for reaction, cooling and drying; the nitrogen source material is m-phenylenediamine.

[0013] Preferably, the preparation method further comprises grinding and sieving.

[0014] Preferably, the sieving is through a 200 mesh sieve.

[0015] Preferably, the nitrogen source material is m-phenylenediamine.

[0016] The molar ratio of the carbon source material, nitrogen source material and 3-aminopropyltriethoxysilane in step (1) is (1.5-2):1:1.5.

[0017] Preferably, the molar ratio of the carbon source material to the nitrogen source material is 3:2.

[0018] Furthermore, the carbon source material is at least one of citric acid and glucose.

[0019] Preferably, the carbon source material is citric acid.

[0020] Furthermore, the solvent for the dissolution in step (1) is a mixed solution of ethanol and water.

[0021] Preferably, the volume ratio of ethanol to water in the mixed solution is 1:1.

[0022] Furthermore, the heating reaction temperature in step (1) is 180-220° C., and the time is 10-40 minutes.

[0023] Furthermore, the dialysis time in step (1) is 24 hours, and the cutoff capacity of the dialysis bag is 1000Da.

[0024] Furthermore, the mass ratio of the silane-functionalized carbon dots, boric acid and rhodamine B in step (2) is: 0.5: (1.5-3): (0.001-0.005).

[0025] Preferably, the mass ratio of the silane-functionalized carbon dots, boric acid, and rhodamine B is 0.5: (1.5-3): 0.003.

[0026] Furthermore, the heating reaction in step (2) is carried out at a temperature of 180-220° C. for 2-4 hours.

[0027] Preferably, the temperature is 220° C. and the time is 2.5 hours.

[0028] In a second aspect, the present invention provides boron-doped silane functionalized carbon dots prepared by the above preparation method.

[0029] In a third aspect, the present invention provides an application of boron-doped silane functionalized carbon dots in detecting food safety.

[0030] Furthermore, the food safety detection is the detection of thiram.

[0031] Furthermore, the detection of thiram includes a phosphorescence ratio detection method and a fluorescence ratio detection method.

[0032] Preferably, the step of detecting thiram is:

[0033] S1. Phosphorescence detection of thiram: 600 μL of 200 μM copper chloride acetonitrile solution was thoroughly mixed with 600 μL of standard working solution of thiram of different concentrations, ranging from 0.1 to 120 μM. After incubation for 20 minutes, 600 μL of 4 mg / mL boron-doped silane functionalized carbon dot acetonitrile solution was added. The mixture was incubated for another 10 minutes before phosphorescence testing.

[0034] S2. Fluorescence detection of thiram: 600 μL of 200 μM copper chloride methanol solution was thoroughly mixed with 600 μL of standard working solution of thiram of different concentrations, ranging from 0.1 to 120 μM. After incubation for 20 minutes, 600 μL of 4 mg / mL boron-doped silane functionalized carbon dot methanol solution was added. The mixture was incubated for another 15 minutes before fluorescence testing.

[0035] S3. Selectivity and interference of phosphorescence detection of thiram:

[0036] 600 μL of 200 μM copper chloride acetonitrile solution and 500 μM acetonitrile solutions of different pesticides were mixed and added to different 2 mL centrifuge tubes. After incubation for 20 minutes, 600 μL of 4 mg / mL boron-doped silane functionalized carbon dot acetonitrile solution was added to the centrifuge tubes. After incubation for 10 minutes, the phosphorescence spectrum of the system was measured.

[0037] Preparation of common ions (such as K + 、Na + Mg 2+ 、Mn 2+ 、Ni 2+ 、Zn 2+ 、Al 3+ Cr 3+ , etc.) and 500 μM acetonitrile standard solution of D-glucose, 300 μL of 200 μM thiram, 300 μL of 400 μM copper chloride and 600 μL of interfering substance standard solution were added to different 2 mL centrifuge tubes. After incubation for 20 minutes, 600 μL of 4 mg / mL boron-doped silane functionalized carbon dot acetonitrile solution was added. After incubation for 10 minutes, the phosphorescence spectrum of the system was measured.

[0038] S4. Selectivity and interference of phosphorescence detection of thiram:

[0039] Selective experiment: 600 μL of a 200 μM copper chloride methanol solution and a 500 μM methanol solution of different pesticides were mixed and added to different 2 mL centrifuge tubes. After incubation for 20 minutes, 600 μL of a 4 mg / mL boron-doped silane functionalized carbon dot methanol solution was added to each centrifuge tube. After incubation for 15 minutes, the fluorescence spectrum of the system was measured.

[0040] Preparation of common ions (such as K + 、Na + Mg 2+ 、Mn 2+ 、Ni 2+ 、Zn 2+ 、Al 3+ Cr 3+ , etc.) and 500 μM methanol standard solution of D-glucose, 300 μL of 200 μM thiram, 300 μL of 400 μM copper chloride and 600 μL of interfering substance standard solution were added to different 2 mL centrifuge tubes. After incubation for 20 minutes, 600 μL of 4 mg / mL boron-doped silane functionalized carbon dot methanol solution was added. After incubation for 15 minutes, the fluorescence spectrum of the system was measured.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) The boron-doped silane-functionalized carbon dots prepared by adjusting the amount of carbon source material, nitrogen source material, 3-aminopropyltriethoxysilane, boric acid and rhodamine B in the present invention have good fluorescence and phosphorescence dual emission characteristics. The silane-functionalized carbon dots are uniformly distributed in the boric acid matrix in the form of silica microspheres and have excellent stability. Effective fluorescence resonance energy transfer is achieved between the silane-functionalized carbon dots and rhodamine B, so that the boron-doped silane-functionalized carbon dots have fluorescence and phosphorescence dual emission signals, which effectively solves the problem of single signal of traditional optical sensing materials.

[0043] (2) The boron-doped silane functionalized carbon dots of the present invention have high sensitivity and selectivity for the detection of thiram. They can accurately identify thiram in the presence of a variety of common pesticides (such as mancozeb, fipronil, carbendazim, fipronil, cartap, chlorothalonil and methicillin, etc.), and are sensitive to common anions in environmental samples (such as Cl - 、SO4 2- etc.), cations (such as K + 、Na + Mg 2+ 、Mn 2+ 、Ni 2+ 、Zn 2+ 、Al 3+ Cr 3+ It has good anti-interference performance against interfering substances in real samples, such as glucose in fruits and vegetables.

[0044] (3) The boron-doped silane functionalized carbon dots of the present invention have a good linear relationship in the detection of thiram by fluorescence and phosphorescence dual signal ratio, thus avoiding the possibility of autofluorescence interference in complex matrices and improving the accuracy of detection;

[0045] (4) The boron-doped silane functionalized carbon dots of the present invention can detect thiram by using a ratiometric method of fluorescence and phosphorescence dual signals. The linear range of detection concentration is 0.1-120 μM, and the detection limit is as low as 0.056 μM, indicating that thiram can be detected quickly and efficiently.

[0046] (5) The preparation method of the present invention is simple, efficient, and easy to mass produce. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 Part of the characterization diagram of Example 1; wherein A is a scanning electron microscope image, B is a transmission electron microscope image, C is an XRD pattern, and D is a thermogravimetric analysis pattern.

[0048] Figure 2 1 is a partial characterization diagram of Example 1; wherein, the high-resolution XPS peaks of Example 1: A is C1s; B is Si 2p; C is O1s; D is B1s; and E is the infrared spectrum of boron-doped silane-functionalized carbon dots (Example 1).

[0049] Figure 3 It is the fluorescence and phosphorescence two-dimensional excitation emission spectrum diagram of Example 1; wherein A is the fluorescence two-dimensional excitation emission spectrum diagram, and B is the phosphorescence two-dimensional excitation emission spectrum diagram.

[0050] Figure 4 1 is a linear relationship diagram between the fluorescence and phosphorescence signals and the concentration of thiram in Example 1; wherein A is the fluorescence response spectrum of Example 1 for different concentrations of thiram, and the lines from top to bottom represent concentrations from 120 μM to 0.1 μM (120 μM, 100 μ, 80 μM, 60 μM, 40 μM, 30 μM, 20 μM, 10 μM, 2 μM, 0.5 μM and 0.1 μM); B is the established fluorescence response spectrum of thiram concentration to Example 1. C is the linear relationship of the change in fluorescence intensity of Example 1; C is the phosphorescence response spectrum of Example 1 to different concentrations of thiram, with the lines from top to bottom representing concentrations from 120 μM to 0.1 μM (120 μM, 100 μ, 80 μM, 60 μM, 40 μM, 30 μM, 20 μM, 10 μM, 2 μM, 0.5 μM and 0.1 μM); D is the established linear relationship between the concentration of thiram and the change in phosphorescence intensity of Example 1.

[0051] Figure 5 It is the selectivity, competitiveness and anti-interference property of the phosphorescence detection of thiram in Example 1; wherein, A is the phosphorescence response spectrum of Example 1 to thiram and other pesticides, B is the effect of other pesticides (500 μM, 1000 μM, 1500 μM) on the phosphorescence signal after thiram (100 μM) is combined with Example 1, and C is the effect of Example 1 on the phosphorescence response of thiram in the presence of various interfering substances.

[0052] Figure 6It is the selectivity, competitiveness and anti-interference property of the fluorescent detection of thiram in Example 1; wherein, A is the fluorescence response spectrum of Example 1 to thiram and other pesticides, B is the effect of other pesticides (500 μM, 1000 μM, 1500 μM) on the fluorescence signal after thiram (100 μM) is combined with Example 1, and C is the effect of Example 1 on the fluorescence response of thiram in the presence of various interfering substances.

[0053] Figure 7 A is the phosphorescence temperature stability, B is the phosphorescence stability under continuous irradiation with a 254 nm ultraviolet lamp, and C is the phosphorescence reproducibility of thiram detected in Example 1.

[0054] Figure 8 A is the fluorescence temperature stability, B is the fluorescence stability under continuous irradiation of 365nm ultraviolet lamp, and C is the fluorescence reproducibility of detecting thiram in Example 1. DETAILED DESCRIPTION

[0055] The present invention is described below through specific embodiments to make the technical solution of the present invention easier to understand and grasp, but the present invention is not limited thereto. The described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0056] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0057] Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without inventive effort shall fall within the scope of protection of the present invention. The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0058] Example 1

[0059] 1. Preparation of silane-functionalized carbon dots, comprising the following steps:

[0060] Citric acid, m-phenylenediamine, and 3-aminopropyltriethoxysilane were dissolved in a mixed solution of 30 mL of ethanol and water in a volume ratio of 1:1 at a ratio of 3:2:3. 1.12 mL of APTES was then added to the mixed solution beaker, ultrasonically dissolved for 5 minutes, and heated to 200°C in a high-temperature drying oven for 30 minutes. After the reaction was completed, the solution was cooled to room temperature and dialyzed for 24 hours to obtain silane-functionalized carbon dots.

[0061] 2. Preparation of Boron-doped Silane-functionalized Carbon Dots:

[0062] Based on the synthesis of silane-functionalized carbon dots, 0.5 g of silane-functionalized carbon dots, 2 g of boric acid, 3 mg of rhodamine B dye and 20 mL of ultrapure water were added to the system and ultrasonically dissolved for 5 minutes. The beaker was sealed with tin foil and transferred to a muffle furnace, heated to 200°C for reaction for 2.5 hours, cooled to room temperature, dried and ground through a 200-mesh sieve to obtain boron-doped silane-functionalized phosphorescent carbon dots with dual signals and dual emissions.

[0063] Example 2

[0064] 1. Preparation of silane-functionalized carbon dots, comprising the following steps:

[0065] Citric acid, m-phenylenediamine, and 3-aminopropyltriethoxysilane were dissolved in a mixed solution of 30 mL of ethanol and water (volume ratio: 1:1) at a ratio of 2:1:1.5. 1.12 mL of APTES was then added to the mixed solution beaker and dissolved by ultrasonication for 5 minutes. The mixture was heated to 200°C in a high-temperature drying oven for 30 minutes. After the reaction was completed, it was cooled to room temperature and dialyzed for 24 hours to obtain silane-functionalized carbon dots.

[0066] 2. Preparation of Boron-doped Silane-functionalized Carbon Dots:

[0067] Based on the synthesis of silane-functionalized carbon dots, 0.5 g of silane-functionalized carbon dots, 3 g of boric acid, 5 mg of rhodamine B dye and 20 mL of ultrapure water were added to the system and ultrasonically dissolved for 5 minutes. The beaker was sealed with tin foil and transferred to a muffle furnace, heated to 180°C for 2 hours, cooled to room temperature, dried and ground through a 200-mesh sieve to obtain boron-doped silane-functionalized phosphorescent carbon dots with dual signals and dual emissions.

[0068] Comparative Example 1

[0069] 1. Preparation of silane-functionalized carbon dots, comprising the following steps:

[0070] Citric acid, o-phenylenediamine, and 3-aminopropyltriethoxysilane were dissolved in a mixed solution of 30 mL of ethanol and water in a volume ratio of 1:1 at a ratio of 3:2:3. 1.12 mL of APTES was then added to the mixed solution beaker, ultrasonically dissolved for 5 minutes, and heated to 200°C in a high-temperature drying oven for 30 minutes. After the reaction was completed, the solution was cooled to room temperature and dialyzed for 24 hours to obtain silane-functionalized carbon dots.

[0071] 2. Preparation of Boron-doped Silane-functionalized Carbon Dots:

[0072] Based on the synthesis of silane-functionalized carbon dots, 0.5 g of silane-functionalized carbon dots, 2 g of boric acid, 3 mg of rhodamine B dye and 20 mL of ultrapure water were added to the system and ultrasonically dissolved for 5 minutes. The beaker was sealed with tin foil and transferred to a muffle furnace, heated to 200°C for reaction for 2.5 hours, cooled to room temperature, dried and ground through a 200-mesh sieve to obtain boron-doped silane-functionalized phosphorescent carbon dots with dual signals and dual emissions.

[0073] Comparative Example 2

[0074] 1. Preparation of silane-functionalized carbon dots, comprising the following steps:

[0075] Citric acid, p-phenylenediamine, and 3-aminopropyltriethoxysilane were dissolved in a mixed solution of 30 mL of ethanol and water in a volume ratio of 1:1 at a ratio of 3:2:3. 1.12 mL of APTES was then added to the mixed solution beaker, ultrasonically dissolved for 5 minutes, and heated to 200°C in a high-temperature drying oven for 30 minutes. After the reaction, the solution was cooled to room temperature and dialyzed for 24 hours to obtain silane-functionalized carbon dots.

[0076] 2. Preparation of Boron-doped Silane-functionalized Carbon Dots:

[0077] Based on the synthesis of silane-functionalized carbon dots, 0.5 g of silane-functionalized carbon dots, 2 g of boric acid, 3 mg of rhodamine B dye and 20 mL of ultrapure water were added to the system and ultrasonically dissolved for 5 minutes. The beaker was sealed with tin foil and transferred to a muffle furnace, heated to 200°C for reaction for 2.5 hours, cooled to room temperature, dried and ground through a 200-mesh sieve to obtain boron-doped silane-functionalized phosphorescent carbon dots with dual signals and dual emissions.

[0078] Comparative Example 3

[0079] 1. Preparation of silane-functionalized carbon dots, comprising the following steps:

[0080] Citric acid, m-phenylenediamine, and 3-aminopropyltriethoxysilane were dissolved in a 1:1:1.5 ratio in 30 mL of a mixed solution of ethanol and water (volume ratio: 1:1). 1.12 mL of APTES was then added to the mixed solution beaker, ultrasonically dissolved for 5 minutes, and heated to 200°C in a high-temperature drying oven for 30 minutes. After the reaction, the solution was cooled to room temperature and dialyzed for 24 hours to obtain silane-functionalized carbon dots.

[0081] 2. Preparation of Boron-doped Silane-functionalized Carbon Dots:

[0082] Based on the synthesis of silane-functionalized carbon dots, 0.5 g of silane-functionalized carbon dots, 2 g of boric acid, 3 mg of rhodamine B dye and 20 mL of ultrapure water were added to the system and ultrasonically dissolved for 5 minutes. The beaker was sealed with tin foil and transferred to a muffle furnace, heated to 200°C for reaction for 2.5 hours, cooled to room temperature, dried and ground through a 200-mesh sieve to obtain boron-doped silane-functionalized phosphorescent carbon dots with dual signals and dual emissions.

[0083] Comparative Example 4

[0084] 1. Preparation of silane-functionalized carbon dots, comprising the following steps:

[0085] Citric acid, m-phenylenediamine, and 3-aminopropyltriethoxysilane were dissolved in a 1:1 mixed solution of 30 mL of ethanol and water at a volume ratio of 0.5:1:1.5. 1.12 mL of APTES was then added to the mixed solution beaker, ultrasonically dissolved for 5 minutes, and heated to 200°C in a high-temperature drying oven for 30 minutes. After the reaction, the solution was cooled to room temperature and dialyzed for 24 hours to obtain silane-functionalized carbon dots.

[0086] 2. Preparation of Boron-doped Silane-functionalized Carbon Dots:

[0087] Based on the synthesis of silane-functionalized carbon dots, 0.5 g of silane-functionalized carbon dots, 2 g of boric acid, 3 mg of rhodamine B dye and 20 mL of ultrapure water were added to the system and ultrasonically dissolved for 5 minutes. The beaker was sealed with tin foil and transferred to a muffle furnace, heated to 200°C for reaction for 2.5 hours, cooled to room temperature, dried and ground through a 200-mesh sieve to obtain boron-doped silane-functionalized phosphorescent carbon dots with dual signals and dual emissions.

[0088] Comparative Example 5

[0089] 1. Preparation of silane-functionalized carbon dots, comprising the following steps:

[0090] Citric acid, m-phenylenediamine, and 3-aminopropyltriethoxysilane were dissolved in a mixed solution of 30 mL of ethanol and water in a volume ratio of 1:1 at a ratio of 0.2:1:1.5. 1.12 mL of APTES was then added to the mixed solution beaker, ultrasonically dissolved for 5 minutes, and heated to 200°C in a high-temperature drying oven for 30 minutes. After the reaction was completed, the solution was cooled to room temperature and dialyzed for 24 hours to obtain silane-functionalized carbon dots.

[0091] 2. Preparation of Boron-doped Silane-functionalized Carbon Dots:

[0092] Based on the synthesis of silane-functionalized carbon dots, 0.5 g of silane-functionalized carbon dots, 2 g of boric acid, 3 mg of rhodamine B dye and 20 mL of ultrapure water were added to the system and ultrasonically dissolved for 5 minutes. The beaker was sealed with tin foil and transferred to a muffle furnace, heated to 200°C for reaction for 2.5 hours, cooled to room temperature, dried and ground through a 200-mesh sieve to obtain boron-doped silane-functionalized phosphorescent carbon dots with dual signals and dual emissions.

[0093] Comparative Example 6

[0094] 1. Preparation of silane-functionalized carbon dots, comprising the following steps:

[0095] Citric acid, m-phenylenediamine, and 3-aminopropyltriethoxysilane were dissolved in a mixed solution of 30 mL of ethanol and water in a volume ratio of 1:1 at a ratio of 3:2:3. 1.12 mL of APTES was then added to the mixed solution beaker, ultrasonically dissolved for 5 minutes, and heated to 200°C in a high-temperature drying oven for 30 minutes. After the reaction was completed, the solution was cooled to room temperature and dialyzed for 24 hours to obtain silane-functionalized carbon dots.

[0096] 2. Preparation of Boron-doped Silane-functionalized Carbon Dots:

[0097] Based on the synthesis of silane-functionalized carbon dots, 0.5 g of silane-functionalized carbon dots, 2 g of boric acid, 3 mg of rhodamine B dye and 20 mL of ultrapure water were added to the system and ultrasonically dissolved for 5 minutes. The beaker was sealed with tin foil and transferred to a muffle furnace, heated to 220°C for reaction for 2.5 hours, cooled to room temperature, dried and ground through a 200-mesh sieve to obtain boron-doped silane-functionalized phosphorescent carbon dots with dual signals and dual emissions.

[0098] Comparative Example 7

[0099] 1. Preparation of silane-functionalized carbon dots, comprising the following steps:

[0100] Citric acid, m-phenylenediamine, and 3-aminopropyltriethoxysilane were dissolved in a mixed solution of 30 mL of ethanol and water in a volume ratio of 1:1 at a ratio of 3:2:3. 1.12 mL of APTES was then added to the mixed solution beaker, ultrasonically dissolved for 5 minutes, and heated to 200°C in a high-temperature drying oven for 30 minutes. After the reaction was completed, the solution was cooled to room temperature and dialyzed for 24 hours to obtain silane-functionalized carbon dots.

[0101] 2. Preparation of Boron-doped Silane-functionalized Carbon Dots:

[0102] Based on the synthesis of silane-functionalized carbon dots, 0.5 g of silane-functionalized carbon dots, 2 g of boric acid, 3 mg of rhodamine B dye and 20 mL of ultrapure water were added to the system and ultrasonically dissolved for 5 minutes. The beaker was sealed with tin foil and transferred to a muffle furnace, heated to 200 ° C for 3 hours, cooled to room temperature, dried and ground through a 200 mesh sieve to obtain boron-doped silane-functionalized phosphorescent carbon dots with dual signals and dual emissions.

[0103] Comparative Example 8

[0104] 1. Preparation of silane-functionalized carbon dots, comprising the following steps:

[0105] Citric acid, m-phenylenediamine, and 3-aminopropyltriethoxysilane were dissolved in a mixed solution of 30 mL of ethanol and water in a volume ratio of 1:1 at a ratio of 3:2:3. 1.12 mL of APTES was then added to the mixed solution beaker, ultrasonically dissolved for 5 minutes, and heated to 200°C in a high-temperature drying oven for 30 minutes. After the reaction was completed, the solution was cooled to room temperature and dialyzed for 24 hours to obtain silane-functionalized carbon dots.

[0106] 2. Preparation of Boron-doped Silane-functionalized Carbon Dots:

[0107] Based on the synthesis of silane-functionalized carbon dots, 0.5 g of silane-functionalized carbon dots, 2 g of boric acid, 3 mg of rhodamine B dye and 20 mL of ultrapure water were added to the system and ultrasonically dissolved for 5 minutes. The beaker was sealed with tin foil and transferred to a muffle furnace, heated to 200 ° C for 3.5 hours, cooled to room temperature, dried and ground through a 200 mesh sieve to obtain boron-doped silane-functionalized phosphorescent carbon dots with dual signals and dual emissions.

[0108] Comparative Example 9

[0109] 1. Preparation of silane-functionalized carbon dots, comprising the following steps:

[0110] Citric acid, m-phenylenediamine, and 3-aminopropyltriethoxysilane were dissolved in a mixed solution of 30 mL of ethanol and water in a volume ratio of 1:1 at a ratio of 3:2:3. 1.12 mL of APTES was then added to the mixed solution beaker, ultrasonically dissolved for 5 minutes, and heated to 200°C in a high-temperature drying oven for 30 minutes. After the reaction was completed, the solution was cooled to room temperature and dialyzed for 24 hours to obtain silane-functionalized carbon dots.

[0111] 2. Preparation of Boron-doped Silane-functionalized Carbon Dots:

[0112] Based on the synthesis of silane-functionalized carbon dots, 0.5 g of silane-functionalized carbon dots, 2 g of boric acid, 3 mg of rhodamine B dye and 20 mL of ultrapure water were added to the system and ultrasonically dissolved for 5 minutes. The beaker was sealed with tin foil and transferred to a muffle furnace, heated to 200 ° C for 4 hours, cooled to room temperature, dried and ground through a 200 mesh sieve to obtain boron-doped silane-functionalized phosphorescent carbon dots with dual signals and dual emissions.

[0113] Test Example 1 Luminous Intensity Test

[0114] Take 1.8 mL of the test system solution and place it in the cuvette of Hitachi FL-7100 fluorescence spectrophotometer. Set the photomultiplier tube voltage to 950 V, the excitation slit to 10 nm, the emission slit to 20 nm, and the excitation wavelength to 270.0 nm to perform the phosphorescence intensity test.

[0115] The test results are shown in Table 1.

[0116] Table 1

[0117] Luminous intensity (au) Example 1 2737.3 Example 2 2271.7 Comparative Example 1 203.5 Comparative Example 2 81.1 Comparative Example 3 1496.7 Comparative Example 4 1198.0 Comparative Example 5 1188.7 Comparative Example 6 484.2 Comparative Example 7 1272.6 Comparative Example 8 682.1 Comparative Example 9 211.3

[0118] Test Example 2: Linear Relationship between Phosphorescence and Substance Concentration

[0119] 1. Detection of Thiram

[0120] Test material: Example 1.

[0121] 600 μL of 200 μM copper chloride acetonitrile solution was thoroughly mixed with 600 μL of different concentrations of thiram standard working solution, with the concentration range of 0.1-120 μM (0.1 μM, 0.5 μM, 2 μM, 10 μM, 20 μM, 30 μM, 40 μM, 60 μM, 80 μM, 100 μM and 120 μM). After incubation for 20 minutes, 600 μL of 4 mg / mL boron-doped silane functionalized carbon dot acetonitrile solution was added. After incubation for another 10 minutes, phosphorescence test was performed. According to the Stern-Volmer formula: (PL 490 / PL 590 )0 / (PL 490 / PL590 )=K[C]+B, where K is the phosphorescence quenching constant, [C] is the concentration of thiram, (PL 490 / PL 590 )0 and (PL 490 / PL 590 ) are the ratios of the phosphorescence intensities at 490 nm and 590 nm when thiram is absent and present, respectively. 490 / PL 590 )0 / (PL 490 / PL 590 ) as the vertical axis, and establish a linear relationship between phosphorescence and substance concentration. The results are as follows Figure 4 As shown, the linear regression equation is (PL 490 / PL 590 )0 / (PL 490 / PL 590 )=1.01514+0.00723X,R 2 =0.997, LOD is 0.056 μM, and the boron-doped silane functionalized carbon dots in Example 1 can sensitively and accurately indicate the content of thiram through phosphorescence signals. The parameters of the spectrophotometer are set as follows: the excitation wavelength is set to 260 nm, and the emission wavelength range is 400-650 nm.

[0122] Selective experiment: 600 μL of a 200 μM copper chloride solution in acetonitrile and 500 μM acetonitrile solutions of different pesticides were mixed and added to different 2 mL centrifuge tubes. After incubation for 20 minutes, 600 μL of a 4 mg / mL boron-doped silane-functionalized carbon dot solution in acetonitrile was added to each centrifuge tube. After incubation for 10 minutes, the phosphorescence spectrum of the system was measured.

[0123] Interference experiment: Preparation of common ions (such as K + 、Na + Mg 2+ 、Mn 2+ 、Ni 2+ 、Zn 2+ 、Al 3+ Cr 3+ ) and D-glucose with a concentration of 500μM acetonitrile standard solution, 300μL of 200μM thiram, 300μL of 400μM copper chloride and 600μL of interfering substance standard solution were added to different 2mL centrifuge tubes. After incubation for 20 minutes, 600μL of 4mg / mL boron-doped silane functionalized carbon dot acetonitrile solution was added. After incubation for 10 minutes, the phosphorescence spectrum of the system was measured. The results are shown in Figure 2. Figure 5 As shown, it has good selectivity and anti-interference ability.

[0124] 2. Stability and Reproducibility Experiments

[0125] Test material: Example 1.

[0126] The phosphorescence intensity of the boron-doped silane functionalized carbon dots was measured once a week for 5 weeks. At the same time, the material was exposed to 254nm UV light for 120 minutes and the phosphorescence intensity was measured every 20 minutes. The phosphorescence intensity of the boron-doped silane functionalized carbon dots was also measured at different temperatures. The phosphorescence detection experiment was performed on 0.1μM and 100μM thiram standard solutions for three consecutive days to evaluate the reproducibility of the experiment. The results are shown in Figure 2. Figure 7 As shown, it has good stability and reproducibility.

[0127] Test Example 3: Linear Relationship between Fluorescence and Substance Concentration

[0128] 1. Detection of Thiram

[0129] Test material: Example 1.

[0130] 600 μL of 200 μM copper chloride methanol solution was thoroughly mixed with 600 μL of different concentrations of thiram standard working solution, with the concentration range of 0.1-120 μM (0.1 μM, 0.5 μM, 2 μM, 10 μM, 20 μM, 30 μM, 40 μM, 60 μM, 80 μM, 100 μM and 120 μM). After incubation for 20 minutes, 600 μL of 4 mg / mL boron-doped silane functionalized carbon dot methanol solution was added, and the fluorescence was tested after incubation for another 15 minutes. According to the Stern-Volmer formula: FL 440 / FL 570 =K[C]+B, where K is the phosphorescence quenching constant, [C] is the concentration of thiram, FL 440 / FL 570 The fluorescence intensity of the system at 440nm and 570nm respectively. With the concentration of the standard working solution as the horizontal axis, the fluorescence intensity ratio FL 440 / FL 570 As the vertical axis, a linear relationship between fluorescence and substance concentration is established. The results are as follows Figure 4 As shown, the linear regression equation is FL 440 / FL 570 =1.79365+0.00467X, linear regression coefficient R 2 =0.993, LOD is 0.052 μM. The boron-doped silane functionalized carbon dots in Example 1 can sensitively and accurately indicate the content of thiram through fluorescence signals. The parameters of the microplate reader are set as follows: the excitation wavelength is set to 360 nm, and the emission wavelength range is 400-650 nm.

[0131] Selective experiment: 600 μL of a 200 μM copper chloride methanol solution and a 500 μM methanol solution of different pesticides were mixed and added to different 2 mL centrifuge tubes. After incubation for 20 minutes, 600 μL of a 4 mg / mL boron-doped silane functionalized carbon dot methanol solution was added to each centrifuge tube. After incubation for 15 minutes, the fluorescence spectrum of the system was measured.

[0132] Interference experiment: Preparation of common ions (such as K + 、Na + Mg 2+ 、Mn 2+ 、Ni 2+ 、Zn 2+ 、Al 3+ Cr 3+ ) and D-glucose with a concentration of 500μM methanol standard solution, 300μL of 200μM thiram, 300μL of 400μM copper chloride and 600μL of interfering substance standard solution were added to different 2mL centrifuge tubes. After incubation for 20 minutes, 600μL of 4mg / mL boron-doped silane functionalized carbon dot methanol solution was added. After incubation for 15 minutes, the fluorescence spectrum of the system was measured. The results are shown in Figure 2. Figure 6 As shown, it has good selectivity and anti-interference ability.

[0133] 2. Stability and Reproducibility Experiments

[0134] Test material: Example 1.

[0135] The fluorescence intensity of the boron-doped silane functionalized carbon dots was measured once a week for 5 weeks. At the same time, the material was exposed to 365nm UV light for 120 minutes and the fluorescence intensity was measured every 20 minutes. The fluorescence intensity of the boron-doped silane functionalized carbon dots was also measured at different temperatures. Fluorescence detection experiments were performed on 0.1μM and 100μM thiram standard solutions for three consecutive days to evaluate the reproducibility of the experiment. The results are shown in Figure 2. Figure 8 As shown, it has good stability and reproducibility.

[0136] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing dual-mode emission boron-doped silane functionalized carbon dots, characterized in that: The steps include: (1) mixing and dissolving a nitrogen source material, 3-aminopropyltriethoxysilane, and a carbon source material, heating for reaction, cooling, and dialyzing to obtain silane-functionalized carbon dots; (2) adding boric acid, rhodamine B and water to the silane-functionalized carbon dots obtained in step (1), heating for reaction, cooling and drying; The nitrogen source material is m-phenylenediamine; The molar ratio of the carbon source material, nitrogen source material and 3-aminopropyltriethoxysilane in step (1) is (1.5-2):1:1.

5.

2. The preparation method according to claim 1, characterized in that The carbon source material is at least one of citric acid and glucose.

3. The preparation method according to claim 1, characterized in that The solvent for the dissolution in step (1) is a mixed solution of ethanol and water.

4. The preparation method according to claim 1, characterized in that The heating reaction temperature in step (1) is 180-200° C. and the time is 10-40 minutes.

5. The preparation method according to claim 1, characterized in that The mass ratio of the silane-functionalized carbon dots, boric acid and rhodamine B in step (2) is: 0.5：(1.5-3)：(0.001-0.005)。 6. The preparation method according to claim 1, characterized in that The heating reaction temperature in step (2) is 180-200° C. and the time is 2-2.5 hours.

7. Dual-mode emission boron-doped silane functionalized carbon dots prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the boron-doped silane-functionalized carbon dots prepared by the preparation method according to any one of claims 1 to 6 or the boron-doped silane-functionalized carbon dots according to claim 7 in food safety detection.

9. The use according to claim 8, characterized in that The food safety test is to test Thiram.

10. The use according to claim 9, characterized in that The detection of thiram includes a phosphorescence ratio detection method and a fluorescence ratio detection method.

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