Material and portable device for trinitrotoluene fluorescence detection

Abstract

The invention relates to the technical field of fluorescence detection, and discloses a material for trinitrotoluene fluorescence detection and a portable device. The fluorescent carbon quantum dot solution is prepared from the following raw materials: an amine compound, persulfate, acid liquor and alkali liquor. The fluorescent carbon quantum dot solution provided by the invention takes an amine compound as a preparation raw material, a large number of electron-rich amino groups are distributed on the surface of a carbon nucleus due to doping of nitrogen, a large number of negative potential sites exist on the surface of the carbon nucleus, and the fluorescent carbon quantum dot solution can react with nitroaromatic explosives with positive potential to bring fluorescence change and realize detection of the explosives; according to the fluorescence detection film, the fluorescent carbon quantum dots in a liquid medium are loaded on a solid medium, so that the fluorescent carbon quantum dots have portability, and the fluorescence characteristics of the fluorescent carbon quantum dots are not influenced; the fluorescence detection device containing the fluorescence detection film can detect trinitrotoluene in a liquid phase mode and a solid phase mode, and is high in sensitivity, simple to operate, low in cost and good in portability.

Description

Technical Field

[0001] The present invention relates to the technical field of fluorescence detection, and particularly to a material and a portable device for the fluorescence detection of trinitrotoluene. Background Art

[0002] Explosives are factors of insecurity and instability, and the chemical substances used therein can cause great pollution to soil and water bodies. Nitroaromatic explosives are a class of explosives mainly composed of nitroaromatic compounds. Among nitroaromatic compounds, trinitrotoluene (TNT) and its degradation product dinitrotoluene (DNT) are the most commonly used compounds in explosive devices and are the key objects for explosive detection.

[0003] At present, there are many effective techniques for detecting trace explosives. The most common ones include ion mobility spectrometry (IMS), mass spectrometry (MS), and gas chromatography (GC). Although these methods can accurately detect the presence and content of explosives, they generally have defects such as large volume of detection equipment, high equipment cost, being operable only by professional technicians, and long detection procedures. Therefore, these detection devices can only be placed in places with controllable detection environments such as laboratories and airports, which greatly limits the practical application scope of these detection technologies.

[0004] Fluorescence detection technology is considered to be one of the most promising technologies for realizing portable detection. However, so far, most of the work still remains at the stage of material development and theoretical research, and the detection still needs to be carried out with the aid of expensive and bulky fluorescence spectrometers in laboratories. Summary of the Invention

[0005] The present invention aims to solve at least one of the above technical problems existing in the prior art. For this reason, one of the purposes of the present invention is to provide a fluorescent carbon quantum dot solution; the second purpose of the present invention is to provide a preparation method of this fluorescent carbon quantum dot solution; the third purpose of the present invention is to provide a fluorescence detection thin film; the fourth purpose of the present invention is to provide a fluorescence detection device; the fifth purpose of the present invention is to provide the application of the fluorescent carbon quantum dot solution, the fluorescence detection thin film, or the fluorescence detection device.

[0006] In order to achieve the above purposes, the technical solutions adopted by the present invention are as follows:

[0007] The first aspect of the present invention provides a fluorescent carbon quantum dot solution, which comprises the following raw materials for preparation: amine compounds, persulfates, acid solutions, and alkali solutions.

[0008] In some embodiments of the present invention, the solid-liquid ratio of the persulfate to the amine compound is 1 g:(2 - 5) mL.

[0009] In some specific embodiments of the present invention, the solid-liquid ratio of the persulfate to the amine compound is 1 g : (2 - 3) mL.

[0010] In some embodiments of the present invention, the amine compound is selected from at least one of aniline, o-phenylenediamine, m-phenylenediamine, and ethylenediamine.

[0011] In some specific embodiments of the present invention, the amine compound is aniline.

[0012] In some embodiments of the present invention, the persulfate is selected from at least one of ammonium persulfate, sodium persulfate, and potassium persulfate.

[0013] In some specific embodiments of the present invention, the persulfate is ammonium persulfate.

[0014] In some embodiments of the present invention, the concentration of the acid solution is 1 - 2 mol / L.

[0015] In some embodiments of the present invention, the acid solution includes hydrochloric acid.

[0016] In some embodiments of the present invention, the pH of the alkali solution is 9 - 11.

[0017] In some embodiments of the present invention, the alkali source of the alkali solution includes alkali metal hydroxides.

[0018] In some specific embodiments of the present invention, the alkali source of the alkali solution includes at least one of sodium hydroxide and potassium hydroxide.

[0019] In some embodiments of the present invention, in the fluorescent carbon quantum dot solution, the particle size of the fluorescent carbon quantum dots is 1.8 - 3.6 nm.

[0020] The second aspect of the present invention provides a method for preparing the fluorescent carbon quantum dot solution described in the first aspect of the present invention, comprising the following steps:

[0021] S1. Mix and react the amine compound, the persulfate, and the acid solution to obtain polyaniline;

[0022] S2. Disperse the polyaniline in the alkali solution, heat and react, perform solid-liquid separation, and collect the liquid phase to obtain the fluorescent carbon quantum dot solution.

[0023] In some embodiments of the present invention, the reaction conditions of step S1 include at least one of the following:

[0024] 1) The pH of the reaction system is 3 - 5;

[0025] 2) The reaction time is 10 - 15 h.

[0026] In some specific embodiments of the present invention, the reaction conditions of step S1 include at least one of the following:

[0027] 1) The pH of the reaction system is 3 - 5;

[0028] 2) The reaction time is 11 - 13 h.

[0029] In some embodiments of the present invention, in step S1, after the reaction ends, it further includes the steps of filtering with suction to collect the solid product, and drying to obtain polyaniline.

[0030] In some embodiments of the present invention, the drying temperature is 65 - 75 °C and the time is 10 - 15 h.

[0031] In some embodiments of the present invention, the reaction conditions of step S2 include at least one of the following:

[0032] 1) The solid-liquid ratio of the polyaniline to the alkali solution is (3 - 7) mg:1 mL;

[0033] 2) The reaction temperature is 200 - 250 °C;

[0034] 3) The reaction time is 10 - 15 h.

[0035] In some specific embodiments of the present invention, the reaction conditions of step S2 include at least one of the following:

[0036] 1) The solid-liquid ratio of the polyaniline to the alkali solution is (4 - 6) mg:1 mL;

[0037] 2) The reaction temperature is 210 - 230 °C;

[0038] 3) The reaction time is 11 - 13 h.

[0039] In some embodiments of the present invention, the raw materials for preparing the fluorescent carbon quantum dot solution further include water.

[0040] In some embodiments of the present invention, the volume ratio of the amine compound to water is (2 - 4):10.

[0041] In some embodiments of the present invention, the solid-liquid ratio of the polyaniline to water is 1 mg:(1.5 - 2.5) mL.

[0042] In some embodiments of the present invention, the method for preparing the fluorescent carbon quantum dot solution specifically includes the following steps:

[0043] Mix the amine compound and water to obtain solution A; mix the persulfate and the acid solution to obtain solution B;

[0044] Place the solution A in an ice-water bath, quickly add the solution B to the solution A, stir and react, filter by suction to collect the solid product, and dry it to obtain polyaniline;

[0045] Disperse the polyaniline in water, ultrasonically clean it for 2 - 5 h to obtain a polyaniline suspension, add an alkali solution, heat and react, take the supernatant, centrifuge and separate, collect the liquid phase to obtain the fluorescent carbon quantum dot solution.

[0046] In some embodiments of the present invention, the rotation speed of the centrifugation is 5000 - 7000 r / min, and the time is 8 - 12 min.

[0047] In the present invention, polyaniline is first synthesized using amine compounds, persulfate, and an acid solution as the main preparation raw materials, and then used as the preparation raw material for the fluorescent carbon quantum dot solution, which can avoid the differences in morphology, nitrogen content, or impurities caused by different polymerization conditions (initiator and pH differences) of commercially available polyaniline, and the adverse effects on the detection effect caused by the differences in the particle size and surface groups of the carbon quantum dots.

[0048] The third aspect of the present invention provides a fluorescent detection film, which includes the following preparation raw materials: the fluorescent carbon quantum dot solution described in the first aspect of the present invention, and non-fluorescent qualitative filter paper.

[0049] In some embodiments of the present invention, the non-fluorescent qualitative filter paper includes Whatman No. 1 qualitative filter paper.

[0050] In some embodiments of the present invention, the fluorescent detection film is prepared by a method including the following steps:

[0051] Crush the non-fluorescent qualitative filter paper to form a powder, soak it in the fluorescent carbon quantum dot solution to obtain a fluorescent carbon quantum dot-modified filter paper powder, and press it to obtain the fluorescent detection film.

[0052] In some embodiments of the present invention, the solid-liquid ratio of the filter paper powder to the fluorescent carbon quantum dot solution is (0.5 - 1.5) g:1 mL.

[0053] In some specific embodiments of the present invention, the solid-liquid ratio of the filter paper powder to the fluorescent carbon quantum dot solution is (0.5 - 1) g:1 mL.

[0054] In some embodiments of the present invention, after the filter paper powder is soaked in the fluorescent carbon quantum dot solution, a step of rolling and grinding is further included.

[0055] In the present invention, a non-fluorescent qualitative filter paper is used as the carrier for loading fluorescent carbon quantum dots. The non-fluorescent qualitative filter paper can provide a low fluorescence background to ensure the success of fluorescence detection. After crushing the non-fluorescent qualitative filter paper and then soaking it in the fluorescent carbon quantum dot solution and performing rolling and grinding, the fluorescent carbon quantum dots can be more evenly loaded on the filter paper powder.

[0056] In some embodiments of the present invention, the pressure for pressing is 8 - 12 MPa.

[0057] In some embodiments of the present invention, after pressing, a drying step is further included.

[0058] In some embodiments of the present invention, the drying temperature is 45 - 55 °C and the time is 10 - 15 h.

[0059] The fourth aspect of the present invention provides a fluorescence detection device, including the fluorescence detection film described in the third aspect of the present invention.

[0060] In some embodiments of the present invention, the fluorescence detection device further includes a housing, a light source, a filter, a slit, a grating, a photoelectric signal converter, and a solid sampler.

[0061] In some embodiments of the present invention, the housing is made of polylactic acid (PLA) as the base material and obtained by 3D printing.

[0062] In some embodiments of the present invention, the light source is a 365 nm ultraviolet lamp.

[0063] In some embodiments of the present invention, the filter includes a 365 nm ultraviolet band-pass filter and a 420 nm long-pass filter.

[0064] In some embodiments of the present invention, the grating includes a diffraction grating.

[0065] In some embodiments of the present invention, the photoelectric signal converter includes a CMOS detector.

[0066] In some embodiments of the present invention, the solid sampler carries the fluorescence detection film.

[0067] The basic principle of the fluorescence detection device of the present invention is described as follows:

[0068] In the present invention, polylactic acid (PLA) is used as a base material to construct the framework of a fluorescence detection device through 3D printing technology. A spectral detector is constructed using a CMOS detector and a diffraction grating. A fluorescence detection film is used as a high-polymer solid detection film. A 365-nm ultraviolet lamp is used as an ultraviolet light source. Visible light from the lamp source is filtered out by a 365-nm ultraviolet band-pass filter and then reaches the fluorescence detection film at an angle of 45° to the light rays of the light source, causing it to emit fluorescence. The fluorescence is emitted at an angle of 90° and passes through a 420-nm long-pass filter to filter out the ultraviolet light from the lamp source and then through a slit. Subsequently, the diffraction grating divides the mixed fluorescence into light beams of different wavelengths, and finally reaches the CMOS detector. By reading the photosensitive intensity of different pixel points on the CMOS through a computer, the fluorescence spectrum of the light-emitting film can be obtained.

[0069] The fifth aspect of the present invention provides the application of the fluorescent carbon quantum dot solution described in the first aspect of the present invention, the fluorescent detection film described in the third aspect, or the fluorescent detection device described in the fourth aspect in the detection of nitroaromatic explosives.

[0070] In some embodiments of the present invention, the nitroaromatic explosives include trinitrotoluene explosives.

[0071] In some embodiments of the present invention, the detection modes of the fluorescent detection device include a solid-phase detection mode and a liquid-phase detection mode.

[0072] In some embodiments of the present invention, the detection limit of trinitrotoluene in the solid-phase detection mode of the fluorescent detection device is 1.632 ppm.

[0073] In some embodiments of the present invention, the detection limit of trinitrotoluene in the liquid-phase detection mode of the fluorescent detection device is 0.8233 ppm.

[0074] In the present invention, the fluorescent carbon quantum dots in the fluorescent carbon quantum dot solution have a size effect, and the particle size range is 1.8 - 3.6 nm, enabling them to emit visible fluorescence under the excitation of ultraviolet light. Due to the presence of a large number of negative potential sites on their surface, they can interact with the positive potential sites of nitroaromatic hydrocarbons, thereby quenching their fluorescence to achieve the detection of nitroaromatic explosives. Therefore, the fluorescent carbon quantum dot solution, as well as the fluorescent detection film and fluorescent detection device prepared based on the fluorescent carbon quantum dot solution, can all be used for the detection of nitroaromatic explosives.

[0075] Compared with the prior art, the beneficial effects of the present invention are:

[0076] 1) The fluorescent carbon quantum dot solution provided by the present invention uses an amine compound as a raw material for preparation to achieve nitrogen doping, enabling a large number of electron-rich amino groups to be distributed on the surface of the carbon core. As a result, a large number of negative potential sites exist on its surface, allowing it to interact with nitroaromatic explosives with positive potential, leading to changes in fluorescence, thereby realizing the detection of explosives.

[0077] 2) The preparation method of the fluorescent carbon quantum dot solution provided by the present invention has simple steps and is suitable for industrial application.

[0078] 3) The fluorescent detection film provided by the present invention is formed by pressing after loading fluorescent carbon quantum dots with non-fluorescent qualitative filter paper powder, enabling the fluorescent carbon quantum dots in the liquid medium to be loaded on the solid medium, making the fluorescent carbon quantum dots portable without affecting their fluorescence characteristics.

[0079] 4) The fluorescent detection device provided by the present invention contains a fluorescent detection film and can detect trinitrotoluene in both liquid and solid phases. The detection limit in the liquid phase can reach 0.8233 ppm, and the detection limit in the solid phase can reach 1.632 ppm. It has high detection sensitivity, simple operation, low detection cost, and good portability, and can be used for real-time detection of trinitrotoluene in different scenarios. Description of the Drawings

[0080] Figure 1 It is a transmission electron microscope photograph of the fluorescent carbon quantum dots in the fluorescent carbon quantum dot solution of Example 1;

[0081] Figure 2 It is a particle size distribution diagram of the fluorescent carbon quantum dots in the fluorescent carbon quantum dot solution of Example 1;

[0082] Figure 3 It is the lattice diffraction fringes of the fluorescent carbon quantum dots in the fluorescent carbon quantum dot solution of Example 1;

[0083] Figure 4 It is the fluorescence emission spectrum of the fluorescent carbon quantum dot solution in Example 1;

[0084] Figure 5 It is the luminescence photograph of the fluorescent carbon quantum dot solution in Example 1 under excitation by sunlight (a) and 365 nm ultraviolet light (b);

[0085] Figure 6 It is the fluorescence emission spectrum of the fluorescent detection film in Example 2;

[0086] Figure 7 It is the luminescence photograph of the fluorescent detection film in Example 2 under excitation by sunlight (a) and 365 nm ultraviolet light (b);

[0087] Figure 8 It is a physical diagram of the fluorescent detection device in Example 3;

[0088] Figure 9 For the linear equation of trinitrotoluene test in liquid phase mode in Application Example 1;

[0089] Figure 10 For the linear equation of trinitrotoluene test in solid phase mode in Application Example 2;

[0090] Figure 11 It is a schematic diagram of the calculation and interaction of the surface potential of the simulated structure of fluorescent carbon quantum dots and trinitrotoluene molecules. Detailed implementation manners

[0091] The content of the present invention will be further described in detail through specific embodiments below. Unless otherwise specified, the raw materials, reagents or devices used in the embodiments can be obtained from conventional commercial channels or can be obtained by existing technical methods. Unless otherwise specified, the test or measurement methods are all conventional methods in the art.

[0092] Example 1

[0093] In this example, a fluorescent carbon quantum dot solution is prepared, and the steps are as follows:

[0094] S11: Add 3 mL of aniline to 10 mL of deionized water, and stir at high speed to uniformly disperse the aniline to obtain solution A; dissolve 1.5 g of ammonium persulfate in 10 mL of 1 mol / L hydrochloric acid to obtain solution B; place solution A in an ice-water bath, quickly add solution B to solution A, and continuously stir for 12 h to obtain a black cross-linked solid; perform suction filtration, collect the black solid and dry it in a vacuum drying oven at 70 °C for 12 h to obtain polyaniline solid powder;

[0095] S21: Add 5 mg of polyaniline powder to 9 mL of deionized water, place it in an ultrasonic cleaner and ultrasonicate for 3 h to crush and suspend the polyaniline powder in water; after ultrasonication, add 1 mL of 1 mol / L sodium hydroxide solution and mix well on a high-speed oscillator; after mixing, transfer it to a 20 mL polytetrafluoroethylene-lined autoclave and perform hydrothermal reaction at 220 °C for 12 h. After naturally cooling to room temperature, a mixed solution of wine-red fluorescent carbon quantum dots and polyaniline is obtained; suck out the supernatant and transfer it to a 15 mL centrifuge tube, and centrifuge at 6000 r / min for 10 min in a high-speed centrifuge. The black solid precipitated at the bottom of the centrifuge tube after centrifugation is unreacted polyaniline powder particles, and the supernatant is separated to obtain a fluorescent carbon quantum dot solution.

[0096] Figure 1 It is a transmission electron microscope photograph of the fluorescent carbon quantum dots in the fluorescent carbon quantum dot solution of Example 1, where, Figure 1 (a) is the transmission electron microscope photograph of the fluorescent carbon quantum dots magnified by 1×10 6 times, Figure 1(b) Magnification of 5×10 5 times transmission electron microscopy image of fluorescent carbon quantum dots; Figure 2 Figure Figure 1 and Figure 2 show that in the fluorescent carbon quantum dot solution prepared in Example 1, carbon quantum dots with sizes of 1.8 - 3.6 nm are dispersed.

[0097] Figure 3 Figure Figure 3 shows that the internal structure of the fluorescent carbon quantum dots has an orderly arranged carbon core lattice.

[0098] Figure 4 Figure Figure 4 shows that the fluorescent carbon quantum dot solution prepared in Example 1 can emit blue fluorescence with a peak at 463 nm under ultraviolet light excitation.

[0099] Figure 5 Figure Figure 5 shows that the fluorescent carbon quantum dot solution prepared in Example 1 shows no fluorescence under sunlight irradiation, but emits bright blue fluorescence under 365 nm ultraviolet light excitation.

[0100] Example 2

[0101] A fluorescent detection film was prepared in this example, and the steps are as follows:

[0102] Using Whatman No. 1 qualitative filter paper as the raw material, it was crushed to obtain filter paper powder. 0.5 g of the filter paper powder was immersed in 1 mL of the fluorescent carbon quantum dot solution prepared in Example 1, and thoroughly ground with an agate mortar for 20 min to uniformly load the fluorescent carbon quantum dots onto the filter paper powder, obtaining fluorescent carbon quantum dot - modified filter paper powder;

[0103] 0.1500 g of the fluorescent carbon quantum dot - modified filter paper powder was taken, and a pressure of 10 MPa was applied using a manual powder press to press the powder into a tablet, which was then transferred to a 50°C forced - air oven and dried for 12 h to obtain the fluorescent detection film.

[0104] Figure 6 Figure Figure 6It can be seen that under ultraviolet light excitation, the fluorescence emission peak position of the fluorescence detection film prepared in Example 2 is basically unchanged compared with that of the fluorescent carbon quantum dot solution in Example 1, and the emission is narrowed to a certain extent, but it does not affect the original blue fluorescence phenomenon of the fluorescent carbon quantum dots in the fluorescence detection film.

[0105] Figure 7 Figures (a) and (b) are the luminescence photos of the fluorescence detection film in Example 2 under daylight and 365 nm ultraviolet light excitation, respectively. It can be seen that Figure 7 after loading the fluorescent carbon quantum dots in the fluorescent carbon quantum dot solution onto the non-fluorescent qualitative filter paper powder and pressing it into a film, under 365 nm ultraviolet light excitation, it still has bright blue fluorescence emission.

[0106] Example 3

[0107] In this example, a fluorescence detection device is constructed as follows:

[0108] Using polylactic acid (PLA) as the substrate, the framework of the fluorescence detection device is constructed by 3D printing technology. The fluorescence detection device consists of a housing, a light source, a filter, a slit, a grating, a photoelectric signal converter, and a solid sampler. Among them:

[0109] The length of the device housing is 158 mm, the width is 67 mm, the height is 46 mm, and the wall thickness is 2 mm; the light source reserved hole is a circular hole with an inner diameter of 22 mm, and it extends 15 mm inward as the light source support, with a wall thickness of 2 mm. The sampling area is a cuboid hollow column with an inner length and width of 13 mm; there is a hole on one side at an angle of 45° with the light source direction, and the center distance from the light source filter is 17 mm. The spectral chamber and the sample chamber are separated by a 4 mm partition. A filter slot and a slit are reserved at the optical path position, and the slit size is 6 * 0.2 mm; the light source uses a 365 nm LED light source, and visible light is filtered out through a 365 nm narrow-band pass filter. The filter in front of the slit uses an L420 long-wave pass filter to filter out the light source and the second harmonic peak. The photoelectric converter uses a CMOS lens as the signal collector. The solid sampler is a cuboid column with a length of 12.5 mm, a width of 12.5 mm, and a height of 43 mm. Circular grooves with a depth of 1 mm and an inner diameter of 8 mm are opened on both sides as the detection area; 0.1500 g of the fluorescent carbon quantum dot-modified filter paper powder before pressing in Example 2 is placed in the groove of the solid sampler, and a pressure of 10 MPa is applied using a manual powder tablet press to press the powder into a tablet, and then it is transferred to a 50 °C blast drying oven and dried for 12 h to form a fluorescence detection film.

[0110] Figure 8 Figure is the physical diagram of the fluorescence detection device in Example 3, where Figure 8 (a) is the top view of the internal structure of the device, Figure 8 (b) is the side view of the device, Figure 8 (c) is the front view of the device.

[0111] Application Example 1

[0112] Detection of trinitrotoluene in liquid phase mode:

[0113] To plot the standard curve for trinitrotoluene detection, a series of trinitrotoluene standard solutions with concentrations of 2 ppm, 4 ppm, 6 ppm, 8 ppm, 10 ppm, 12 ppm, 14 ppm, 16 ppm, 18 ppm, and 20 ppm were prepared. Before testing, the fluorescence detection device was first turned on and preheated for 25 min. 1 mL of deionized water was taken in a cuvette, and then 20 μL of the fluorescent carbon quantum dot solution in Example 1 was added, and its fluorescence signal value was measured as the initial intensity F 0 , Subsequently, 1 mL of each of the above-prepared trinitrotoluene solutions with different concentrations was taken in a cuvette, 20 μL of the fluorescent carbon quantum dot solution in Example 1 was added, and its fluorescence intensity was measured and recorded as F. The quenching degree of fluorescence at different concentrations (F 0 -F) was recorded, and a linear equation was fitted. Figure 9 For the linear equation of trinitrotoluene test in liquid phase mode in Application Example 1, from Figure 9 it can be seen that there is a linear relationship between the quenching degree of fluorescence of the fluorescent carbon quantum dot solution after contacting the trinitrotoluene solution and the concentration of the trinitrotoluene solution. Therefore, quantitative detection of trinitrotoluene can be carried out based on this linear equation.

[0114] During actual testing, 1 mL of the fluorescent carbon quantum dot solution was prepared with the actual trinitrotoluene solution, and the quenching degree of fluorescence (F 0 -F) was read out, and the concentration of the actual trinitrotoluene solution was inversely deduced according to the standard linear equation. The blank sample was repeatedly tested, and the recorded standard deviation value was 0.7531. According to the equation LOD = 3SD / k, the detection limit of this method for trinitrotoluene was calculated to be 0.8233 ppm.

[0115] Application Example 2

[0116] Detection of trinitrotoluene in solid phase mode:

[0117] To plot the standard curve for trinitrotoluene detection, a series of trinitrotoluene standard solutions with concentrations of 2 ppm, 4 ppm, 6 ppm, 8 ppm, 10 ppm, 12 ppm, 14 ppm, 16 ppm, 18 ppm, and 20 ppm were prepared. Before testing, the fluorescence detection device was first turned on and preheated for 25 min. 25 μL of deionized water was dropped onto the fluorescence detection film, and the fluorescence signal value of the original fluorescence detection film was measured and recorded as F 0 , Subsequently, 25 μL of the standard solutions to be measured with different concentrations was dropped onto the fluorescence detection film, and its fluorescence intensity was measured and recorded as F. The quenching degree of fluorescence at different concentrations (F 0 -F) was recorded, and a linear equation was fitted.Figure 10 For the linear equation of solid-phase mode trinitrotoluene test in Application Example 2, from Figure 10 it can be seen that the fluorescence quenching degree of the fluorescence detection film after contacting the trinitrotoluene solution has a linear relationship with the concentration of the trinitrotoluene solution. Therefore, the quantitative detection of trinitrotoluene can be carried out according to this linear equation.

[0118] During actual testing, 25 μL of the actual sample solution to be tested is added dropwise, and the fluorescence quenching degree (F 0 -F) is read out, and the concentration of the actual trinitrotoluene solution is deduced back according to the standard linear equation. The detection limit of this method for trinitrotoluene is 1.632 ppm.

[0119] Figure 11 For the schematic diagram of the calculation and interaction of the surface potential of the fluorescence carbon quantum dot simulation structure and the trinitrotoluene molecule, from Figure 11 it can be seen that the fluorescence quenching of the fluorescence carbon quantum dot after contacting the trinitrotoluene molecule is caused by the interaction force of the potential difference between the surface of the fluorescence carbon quantum dot and the surface of the trinitrotoluene molecule.

Claims

1. A fluorescent carbon quantum dot solution, characterized in that The preparation method comprises the following raw materials: amine compounds, persulfate, acid solution and alkali solution.

2. The fluorescent carbon quantum dot solution according to claim 1, characterized in that The solid-liquid ratio of the persulfate to the amine compound is 1 g:(2-5) mL; And / or, the concentration of the acid solution is 1-2 mol / L; And / or, the pH of the alkali solution is 9-11.

3. The fluorescent carbon quantum dot solution according to claim 1 or 2, characterized in that: The amine compound is selected from at least one of aniline, o-phenylenediamine, m-phenylenediamine and ethylenediamine; And / or, the persulfate is selected from at least one of ammonium persulfate, sodium persulfate and potassium persulfate; And / or, the alkali source of the alkali solution comprises an alkali metal hydroxide.

4. The method for preparing the fluorescent carbon quantum dot solution according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1, mixing an amine compound, a persulfate and an acid solution to react to obtain polyaniline; S2, dispersing the polyaniline in an alkaline solution, heating for reaction, solid-liquid separation, collecting the liquid phase, and obtaining the fluorescent carbon quantum dot solution.

5. The preparation method according to claim 4, characterized in that: The reaction conditions of step S1 include at least one of the following: 1) The pH of the reaction system is 3-5; 2) The reaction time is 10-15h; And / or, the reaction conditions of step S2 include at least one of the following: 1) The solid-liquid ratio of the polyaniline to the alkali solution is (3-7) mg:1 mL; 2) The reaction temperature is 200-250°C; 3) The reaction time is 10-15h.

6. A fluorescence detection film, characterized in that: The preparation method comprises the following raw materials: the fluorescent carbon quantum dot solution according to any one of claims 1 to 3, and non-fluorescent qualitative filter paper.

7. The fluorescence detection film according to claim 6, characterized in that: The fluorescence detection film is prepared by a method comprising the following steps: The non-fluorescent qualitative filter paper is crushed into powder, immersed in a fluorescent carbon quantum dot solution to obtain a filter paper powder modified with fluorescent carbon quantum dots, and pressed to obtain the fluorescent detection film.

8. The fluorescence detection film according to claim 7, characterized in that: The solid-to-liquid ratio of the filter paper powder to the fluorescent carbon quantum dot solution is (0.5-1.5) g:1 mL.

9. A fluorescence detection device, characterized in that: The invention comprises the fluorescence detection film as described in any one of claims 6 to 8.

10. Use of the fluorescent carbon quantum dot solution according to any one of claims 1 to 3, the fluorescent detection film according to any one of claims 6 to 8, or the fluorescent detection device according to claim 9 in the detection of nitroaromatic explosives.

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