Method for regulating and controlling content of amino on surface of o-phenylenediamine / polyethyleneimine carbonized polymer point and application of o-phenylenediamine / polyethyleneimine carbonized polymer point

Abstract

The invention relates to an o-phenylenediamine / polyethyleneimine carbonized polymer dot surface amido content regulation and control method and application, and the method comprises the following steps: by taking o-phenylenediamine, polyethyleneimine, hydrogen peroxide and hydrochloric acid as raw materials, adjusting the feeding ratio of precursors o-phenylenediamine and polyethyleneimine, and preparing the o-phenylenediamine / polyethyleneimine carbonized polymer dot surface amido content. The o-phenylenediamine / polyethyleneimine carbonized polymer dot with rich amino content is obtained by adopting a hydrothermal method, can realize colorimetric-fluorescent dual-mode distinguishing and recognition of 2, 4, 6-trinitrotoluene and 2, 4, 6-trinitrophenol, has higher response speed less than 1s, has better detection sensitivity, has the fluorescence detection limit as low as 324nM and 21.08 nM, has the colorimetric detection limit as low as 255mM and 318.6 nM, and can be used for detecting the content of 2, 4, 6-trinitrotoluene and 2, 4, 6-trinitrophenol. Other analogues with common structures and properties have no interference on detection, and the like. The paper-based sensing material loaded with o-phenylenediamine / polyethyleneimine carbonized polymer dots is constructed by using a soaking method, and on-site rapid detection of 2, 4, 6-trinitrotoluene and 2, 4, 6-trinitrophenol solid particles and atmosphere can be efficiently and conveniently realized without pre-treatment of an object to be detected.

Description

Technical Field

[0001] The invention relates to a method for controlling the surface amine content of o-phenylenediamine / polyethyleneimine carbonized polymer dots and application thereof. Background Art

[0002] Carbonized polymer dots have a unique structure with a carbon core as the center and a polymer chain as the shell. They are generally considered to be a state between fully carbonized carbon dots and polymers, and have the characteristics of both carbon dots and polymers. Carbonized polymer dots show good biocompatibility, low toxicity, photoluminescence, and abundant surface functional groups, and are widely used in fluorescent labeling, drug delivery, bioimaging, catalysis, sensing and other fields. The luminescence of carbonized polymer dots is mainly attributed to the interaction between the carbon core or specific small molecules inside them and the polymer, which is closely related to the reaction conditions, precursors, etc. In addition, different precursors affect the functional groups on the surface of carbonized polymer dots, and the adjustable abundance of functional groups provides the possibility for a wide range of applications. Currently, carbonized polymer dots used for detection are usually synthesized in one step considering the characteristics of the target, while the abundance of functional groups and the efficiency of target recognition are ignored. Therefore, whether the abundant functional groups on the surface of carbonized polymer dots can adjust their reactivity and effective collision efficiency with the target analyte by adjusting the density of recognition sites, thereby improving the detection sensitivity, remains unknown, but it is of great significance for the rational design of functionalized carbonized polymer dots.

[0003] 2,4,6-Trinitrotoluene and 2,4,6-trinitrophenol are nitroaromatic explosives. Due to their stable physical and chemical properties, they are not easy to decompose quickly. Their long-term accumulation can lead to the pollution of terrestrial and aquatic ecosystems, which has adverse effects on the environment and human health. Therefore, the high sensitivity, rapid and on-site identification of trace 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol is of great significance for environmental and safety requirements.

[0004] At present, scientists at home and abroad have developed a series of detection methods for 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol, mainly including chromatography-mass spectrometry, Raman spectroscopy, electrochemical method, colorimetry, fluorescence, colorimetry-fluorescence dual mode and other means to achieve the detection of 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol. The colorimetric-fluorescence method has the characteristics of rapid detection, high sensitivity, low cost and real-time detection, which meets the development needs and is favored by researchers. Based on the electron-deficient characteristics of 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol, the present invention utilizes the electron-rich characteristics of amine groups to construct carbonized polymer dots with rich amine groups to achieve the distinction and identification of 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol, and has a fast response speed, high detection sensitivity and excellent selectivity. Summary of the invention

[0005] The present invention aims to provide a method for controlling the surface amine content of o-phenylenediamine / polyethyleneimine carbonized polymer dots and its use. The method uses o-phenylenediamine and polyethyleneimine as precursors to form a cross-linked network structure through a hydrothermal reaction, and finally obtains o-phenylenediamine / polyethyleneimine carbonized polymer dots through dehydration and carbonization. The obtained o-phenylenediamine / polyethyleneimine carbonized polymer dots are then dispersed in a mixed solvent of methanol and N,N-dimethylformamide to obtain an o-phenylenediamine / polyethyleneimine carbonized polymer dot sensing reagent; the o-phenylenediamine / polyethyleneimine carbonized polymer dots are used. 1 Carbonized polymer dot sensing reagents directly detect 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol, showing fluorescence quenching in the fluorescence channel. In the colorimetric channel, 2,4,6-trinitrotoluene changes from colorless to reddish brown, and 2,4,6-trinitrophenol changes from colorless to yellow-green. The response speed is fast (<1s), the detection sensitivity is high, and the detection limit is low (2,4,6-trinitrotoluene: 324nM and 255μM; 2,4,6-trinitrophenol: 21.08nM and 318.6nM). It has quite good selectivity in the presence of 20 interferences. In addition, by constructing o-phenylenediamine / polyethyleneimine 1 The carbonized polymer dot-loaded paper-based sensing material further verified the practicality of the o-phenylenediamine / polyethyleneimine carbonized polymer dot sensing reagent, which can distinguish 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol particles and vapors as low as pg and ppm levels, respectively. It has high selectivity, and other common structural and property analogs have no interference with the detection, and real-time detection can be achieved.

[0006] The method for controlling the surface amine content of o-phenylenediamine / polyethyleneimine carbonized polymer dots of the present invention is carried out according to the following steps:

[0007] Preparation of a series of o-phenylenediamine / polyethyleneimine carbonized polymer dots:

[0008] a. Mix 0.108 g of o-phenylenediamine with 0.108 g, 0.054 g, and 0.036 g of polyethyleneimine, 0.8 mL of 20% hydrogen peroxide, and 1.48 mL of 2M hydrochloric acid, add them to 50 mL of deionized water, mix them evenly by ultrasonication for 20 minutes, put them into a 100 mL polytetrafluoroethylene-lined reactor, react at 120° C. for 10 hours, and obtain a mixed solution;

[0009] b. The mixed solution obtained in step a was filtered through a 0.22 μm needle filter, dialyzed for 24 h using a dialysis bag with a molecular weight cutoff of 500-1000, and freeze-dried to obtain a series of o-phenylenediamine / polyethyleneimine carbonized polymer dots, i.e., o-phenylenediamine / polyethyleneimine 1 Carbonized polymer dots, o-phenylenediamine / polyethyleneimine 2Carbonized polymer dots or o-phenylenediamine / polyethyleneimine 3 Carbonized polymer dots;

[0010] Preparation of a series of o-phenylenediamine / polyethyleneimine carbonized polymer dot sensing reagents:

[0011] c. Dissolve the series of o-phenylenediamine / polyethyleneimine carbonized polymer dots obtained in step b in a mixed solvent of methanol and N,N-dimethylformamide in a volume ratio of 1:3 to obtain a series of o-phenylenediamine / polyethyleneimine carbonized polymer dot sensing reagents, i.e., o-phenylenediamine / polyethyleneimine 1 Carbonized polymer dot sensing reagent, o-phenylenediamine / polyethyleneimine 2 Carbonized polymer dot sensing reagent or o-phenylenediamine / polyethyleneimine 3 Carbonized polymer dot sensing reagents.

[0012] The o-phenylenediamine / polyethyleneimine carbonized polymer dot sensing reagent obtained by the method is used to prepare 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol solutions for detection, and the following steps are performed:

[0013] Detection of 2,4,6-trinitrotoluene solution by o-phenylenediamine / polyethyleneimine carbonized polymer dot sensing reagent:

[0014] Take 5 mg / mL 2,4,6-trinitrotoluene solution and add the obtained o-phenylenediamine / polyethyleneimine 1 Carbonized polymer dots, o-phenylenediamine / polyethyleneimine 2 Carbonized polymer dots or o-phenylenediamine / polyethyleneimine 3 In the carbonized polymer dot sensing reagent, the fluorescence spectrum and ultraviolet absorption spectrum were measured under the condition of excitation wavelength of 365nm;

[0015] Take 0-2 mg / mL 2,4,6-trinitrotoluene solution and add the obtained o-phenylenediamine / polyethyleneimine 1 In the carbonized polymer dot sensing reagent, under the condition of excitation wavelength of 365nm, the fluorescence spectrum and ultraviolet absorption spectrum were measured. 2,4,6-trinitrotoluene and o-phenylenediamine / polyethyleneimine carbonized polymer dots formed a Meisenheimer complex, which changed the colorimetric color from colorless to reddish brown. The fluorescence resonance energy transfer between the Meisenheimer complex and 2,4,6-trinitrotoluene molecules caused the fluorescence color to gradually change from yellow to light yellow, accompanied by a red shift in the peak position.

[0016] Detection of 2,4,6-trinitrophenol solution by o-phenylenediamine / polyethyleneimine carbonized polymer dot sensing reagent:

[0017] Take 5 mg / mL 2,4,6-trinitrophenol solution and add the obtained o-phenylenediamine / polyethyleneimine 1Carbonized polymer dots, o-phenylenediamine / polyethyleneimine 2 Carbonized polymer dots or o-phenylenediamine / polyethyleneimine 3 In the carbonized polymer dot sensing reagent, the fluorescence spectrum and ultraviolet absorption spectrum were measured under the condition of excitation wavelength of 365nm;

[0018] Take 0-500 μg / mL 2,4,6-trinitrophenol solution and add the obtained o-phenylenediamine / polyethyleneimine 1 In the carbonized polymer dot sensing reagent, the fluorescence spectrum and ultraviolet absorption spectrum were measured under the condition of excitation wavelength of 365nm. Under the colorimetric conditions, the color changed from colorless to yellow-green. The electron transfer between molecules caused the fluorescence color of 2,4,6-trinitrophenol to change from yellow to colorless.

[0019] The o-phenylenediamine / polyethyleneimine obtained by the method 1 Carbonized polymer dot sensing reagents are used to prepare solid particles of 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol and detect the atmosphere. The specific operation is carried out according to the following steps:

[0020] o-phenylenediamine / polyethyleneimine 1 Preparation of carbonized polymer dots loaded paper-based sensing materials:

[0021] a. Select an area of ​​4cm 2 Commercial filter paper was soaked in the obtained o-phenylenediamine / polyethyleneimine 1 Carbonized polymer dot sensing reagent, taken out after 1 minute, to obtain o-phenylenediamine / polyethyleneimine 1 Carbonized polymer dots loaded paper-based sensing materials;

[0022] o-phenylenediamine / polyethyleneimine 1 Detection of 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol solid particles by carbonized polymer dot-loaded paper-based sensing materials:

[0023] b. Spraying 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol particles onto the o-phenylenediamine / polyethyleneimine obtained in step a, respectively. 1 On the carbonized polymer dot paper-based sensing material, under the condition of excitation wavelength of 365nm, the fluorescence color change was observed by naked eyes, 2,4,6-trinitrotoluene changed from yellow-green to reddish brown; 2,4,6-trinitrophenol changed from yellow-green to dark green;

[0024] o-phenylenediamine / polyethyleneimine 1 Carbonized polymer dot-loaded paper-based sensing material for the detection of 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol atmospheres:

[0025] c. Weigh 0.0100 g of 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol solid particles and place them in small bottles. 1 The paper-based sensing material of carbonized polymer dots was placed in a sealed bottle, and the vial was placed in an oven at 50°C, 60°C, 70°C or 80°C to prepare an atmosphere of 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol. Under the excitation wavelength of 365nm, the fluorescence color of 2,4,6-trinitrotoluene changed from yellow-green to reddish brown when observed with the naked eye; the fluorescence color of 2,4,6-trinitrophenol changed from yellow-green to colorless and then to yellow-green.

[0026] The present invention discloses a method for controlling the surface amine content of o-phenylenediamine / polyethyleneimine carbonized polymer dots and its use. The method detects 2,4,6-trinitrotoluene (TNT) based on fluorescence resonance energy transfer and 2,4,6-trinitrophenol (TNP) based on the reaction mechanism of electron intermolecular transfer under light induction. The specific reaction process is as follows:

[0027] o-phenylenediamine / polyethyleneimine 1 The amine groups on the surface of carbonized polymer dots form a Meisenheimer complex with 2,4,6-trinitrotoluene (TNT), which leads to fluorescence resonance energy transfer between it and 2,4,6-trinitrotoluene (TNT) molecules, fluorescence quenching in the fluorescence channel, and the color gradually changes to reddish brown in the colorimetric channel; there is a strong hydrogen bond force between it and the hydroxyl group of 2,4,6-trinitrophenol (TNP), resulting in the formation of o-phenylenediamine / polyethyleneimine 1 The electron transfer between the amine groups on the surface of carbonized Pdots and 2,4,6-trinitrophenol (TNP) molecules resulted in fluorescence quenching in the fluorescence channel and a gradual change of color to yellow-green in the colorimetric channel.

[0028] By adjusting the feed ratio of precursor o-phenylenediamine to polyethyleneimine, o-phenylenediamine / polyethyleneimine carbonized polymer dots with abundant amino groups on the surface were systematically designed for the detection of 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP); the surface of o-phenylenediamine / polyethyleneimine carbonized polymer dots was rich in amino groups, which belonged to the aliphatic -NH 2 The increase in the content of the groups can improve the detection performance of 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP); when the ratio of o-phenylenediamine to polyethyleneimine is 1 and the surface -NH 2 When the content is 26.06%, o-phenylenediamine / polyethyleneimine 1Carbonized polymer dots exhibit excellent sensing performance for 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP), with low fluorescence and colorimetric detection limits of 324 nM and 255 μM for 2,4,6-trinitrotoluene (TNT), 21.08 nM and 318.6 nM for 2,4,6-trinitrophenol (TNP), fast response speed of < 1 s, and excellent specificity even in the presence of 20 interferents; based on o-phenylenediamine / polyethyleneimine 1 The paper sensing material loaded with carbonized polymer dots further verified the practicality of o-phenylenediamine / polyethyleneimine carbonized polymer dots. The sensing material was able to detect and distinguish 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) particles and vapor as low as 17.80pg, 18.99pg and 0.293ppm, 0.334ppm, respectively. This method verified that the increase in the surface amine content can effectively improve the detection performance of carbonized polymer dots for electron-deficient target substances. The designed o-phenylenediamine / polyethyleneimine carbonized polymer dots 1 Carbonized polymer dots have the advantages of fast detection speed, strong anti-interference and high sensitivity for 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol solutions, solids and atmospheres. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The composition diagram of the sensing material of the present invention, wherein (a) o-phenylenediamine / polyethyleneimine 1 Carbonized polymer dots (OPD / PEI 1 CPDs), (b) o-phenylenediamine / polyethyleneimine 2 Carbonized polymer dots (OPD / PEI 2 CPDs), (c) o-phenylenediamine / polyethyleneimine 3 Carbonized polymer dots (OPD / PEI 3 Energy dispersive spectroscopy (EDS) mapping of C, N, and O elements of CPDs, (d) corresponding bar graphs of the N element content of three o-phenylenediamine / polyethyleneimine carbonized PPDs;

[0030] Figure 2 The fluorescence spectra of the present invention are obtained after 270 μL of a 0.1 mg / mL detection solution reacts with 30 μL of a 5 mg / mL aqueous solution of 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) in a mixed solvent of methanol:N,N-dimethylformamide, wherein (a) o-phenylenediamine / polyethyleneimine 1 Carbonized polymer dots (OPD / PEI 1 CPDs), (b) o-phenylenediamine / polyethyleneimine 2 Carbonized polymer dots (OPD / PEI2 (CPDs), (c) o-phenylenediamine / polyethylenimine 3 Oxidized Polymer Dots (OPD / PEI 3 Fluorescence spectra of carbonized polymer dots (OPD / PEI

[0031] Figure 3 For the present invention, in a mixed solvent of methanol:N,N-dimethylformamide, 270 μL of a detection solution with a concentration of 0.1 mg / mL was reacted with 30 μL of aqueous solutions of 2,4,6-trinitrotoluene (TNT) with concentrations of 0 - 2 mg / mL, respectively. The fluorescence spectra and ultraviolet absorption spectra are shown, where (a) o-phenylenediamine / polyethylenimine 1 Carbonized Polymer Dots (OPD / PEI 1 Fluorescence spectra and corresponding optical images of carbonized polymer dots (OPD / PEI 1 Carbonized Polymer Dots (OPD / PEI 1 Absorption spectra and corresponding optical images of carbonized polymer dots (OPD / PEI

[0032] Figure 4 For the present invention, in a mixed solvent of methanol:N,N-dimethylformamide, 270 μL of a detection solution with a concentration of 0.1 mg / mL was reacted with 30 μL of aqueous solutions of 2,4,6-trinitrophenol (TNP) with concentrations of 0 - 500 μg / mL, respectively. The fluorescence spectra and ultraviolet absorption spectra are shown, where (a) o-phenylenediamine / polyethylenimine 1 Carbonized Polymer Dots (OPD / PEI 1 Fluorescence spectra and corresponding optical images of carbonized polymer dots (OPD / PEI 1 Carbonized Polymer Dots (OPD / PEI 1 Absorption spectra and corresponding optical images of carbonized polymer dots (OPD / PEI

[0033] Figure 5 For the present invention, in a mixed solvent of methanol:N,N-dimethylformamide, 270 μL of a detection solution with a concentration of 0.1 mg / mL was reacted with 30 μL of aqueous solutions of 2,4,6-trinitrotoluene (TNT) with concentrations of 0 - 2 mg / mL and 2,4,6-trinitrophenol (TNP) with concentrations of 0 - 500 μg / mL, respectively. The change curve of the fluorescence peak intensity at 553 nm with the concentrations of 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) is shown, where o-phenylenediamine / polyethylenimine 1 Carbonized Polymer Dots (OPD / PEI 1Relationship between the fluorescence intensity at 553 nm and the concentrations of 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) after the CPDs sensing reagent reacts with (a) 2,4,6-trinitrotoluene (TNT) and (b) 2,4,6-trinitrophenol (TNP) solutions;

[0034] Figure 6 The present invention is a mixed solvent of methanol: N, N-dimethylformamide, in which 270 μL of a detection solution with a concentration of 0.1 mg / mL is reacted with 30 μL of a 0-2 mg / mL 2,4,6-trinitrotoluene (TNT) and a 0-500 g / mL 2,4,6-trinitrophenol (TNP) aqueous solution, wherein o-phenylenediamine / polyethyleneimine 1 Carbonized polymer dots (OPD / PEI 1 Figure 3. Relationship between the absorbance ratio at 466 nm and 376 nm after the CPDs sensing reagent reacts with (a) 2,4,6-trinitrotoluene (TNT) solution and the concentration of TNT; (b) the absorbance ratio at 376 nm after the CPDs sensing reagent reacts with the concentration of TNP.

[0035] Figure 7 The present invention is a curve of fluorescence peak intensity at 553nm and reaction time and a curve of RGB value and reaction time after 270 μL of a detection solution with a concentration of 0.1 mg / mL and 10 mg / mL of 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) aqueous solutions react in a mixed solvent of methanol:N,N-dimethylformamide, wherein o-phenylenediamine / polyethyleneimine 1 Carbonized polymer dots (OPD / PEI 1 (a) Fluorescence and (b) colorimetric response time of CPDs sensing reagents with 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) solutions;

[0036] Figure 8 In the present invention, in a mixed solvent of methanol:N,N-dimethylformamide, 270 μL of a detection solution with a concentration of 0.1 mg / mL is mixed with 30 μL of 70.4 mM 2,4,6-trinitrotoluene (TNT), 2,4,6-trinitrophenol (TNP), 2,4-dinitrotoluene (DNT), m-dinitrobenzene (m-DNB), o-nitrobenzoic acid (2-NA), toluene (MB), p-xylene (1,4-DMB), o-phthalonitrile (1,2-DCB), xylene isomers (DMB), p-toluenesulfonic acid (4-TSA), benzoic acid (BNE), CaCl 2 ,Gd(NO 3 )3 、AlCl 3 、KSCN、Ti(SO 4 ) 2 、(CH3COO) 2 Fluorescence spectra of Zn, LiCl, NaI, starch and flour aqueous solutions after reaction, among which o-phenylenediamine / polyethyleneimine 1 (a) Fluorescence selectivity and (b) absorption selectivity of carbonized polymer dot sensing agents for 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP).

[0037] Fig. 9 The present invention contains o-phenylenediamine / polyethyleneimine 1 2,4,6-Trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) particles were sprayed on the carbonized polymer dot-loaded paper-based sensing material, and the particle fluorescence image was taken by a camera. 1 Fluorescence response of carbonized polymer dots loaded paper-based sensing materials to (a) 2,4,6-trinitrotoluene (TNT) and (b) 2,4,6-trinitrophenol (TNP) solid particles;

[0038] Fig.10 The present invention contains o-phenylenediamine / polyethyleneimine 1 The carbonized polymer dot-loaded paper-based sensing material was placed in an atmosphere of 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) and the fluorescence image was taken by a camera. 1 Response of carbonized polymer dots-loaded paper-based sensing materials to (a) 2,4,6-trinitrotoluene (TNT) and (b) 2,4,6-trinitrophenol (TNP) atmospheres. DETAILED DESCRIPTION

[0039] The present invention is further described below by means of specific examples, but the invention is not limited to these examples.

[0040] Example 1

[0041] o-phenylenediamine / polyethyleneimine 1 Preparation of carbonized polymer dots:

[0042] a. Mix 0.108 g of o-phenylenediamine with 0.108 g of polyethyleneimine, 0.8 mL of 20% hydrogen peroxide, and 1.48 mL of 2M hydrochloric acid, add them to 50 mL of deionized water, mix them evenly by ultrasonication for 20 minutes, put them into a 100 mL polytetrafluoroethylene-lined reactor, react at 120° C. for 10 hours to obtain a mixed solution;

[0043] b. Filter the mixed solution obtained in step a with a 0.22 micron needle filter, dialyze for 24 hours with a dialysis bag with a molecular weight cutoff of 500-1000, and freeze-dry to obtain o-phenylenediamine / polyethyleneimine 1 Carbonized polymer dots;

[0044] o-phenylenediamine / polyethyleneimine 1 Preparation of carbonized polymer dot sensing reagents:

[0045] c. The o-phenylenediamine / polyethyleneimine obtained in step b 2 The carbonized polymer dots were dissolved in a mixed solvent of methanol and N,N-dimethylformamide in a volume ratio of 1:3 to obtain o-phenylenediamine / polyethyleneimine. 1 Carbonized polymer dots.

[0046] Example 2

[0047] o-phenylenediamine / polyethyleneimine 2 Preparation of carbonized polymer dots:

[0048] a. Mix 0.108 g of o-phenylenediamine with 0.054 g of polyethyleneimine, 0.8 mL of 20% hydrogen peroxide, and 1.48 mL of 2M hydrochloric acid, add them to 50 mL of deionized water, mix them by ultrasonic for 20 minutes, put them into a 100 mL polytetrafluoroethylene-lined reactor, react at 120° C. for 10 hours, and obtain a mixed solution;

[0049] b. Filter the mixed solution obtained in step a with a 0.22 micron needle filter, dialyze for 24 hours with a dialysis bag with a molecular weight cutoff of 500-1000, and freeze-dry to obtain o-phenylenediamine / polyethyleneimine 2 Carbonized polymer dots;

[0050] o-phenylenediamine / polyethyleneimine 2 Preparation of carbonized polymer dot sensing reagents:

[0051] c. The o-phenylenediamine / polyethyleneimine obtained in step b 2 The carbonized polymer dots were dissolved in a mixed solvent of methanol and N,N-dimethylformamide in a volume ratio of 1:3 to obtain o-phenylenediamine / polyethyleneimine. 2 Carbonized polymer dot sensing reagents.

[0052] Example 3

[0053] o-phenylenediamine / polyethyleneimine 3 Preparation of carbonized polymer dots:

[0054] a. Mix 0.108 g of o-phenylenediamine with 0.036 g of polyethyleneimine, 0.8 mL of 20% hydrogen peroxide, and 1.48 mL of 2M hydrochloric acid, add them to 50 mL of deionized water, mix them evenly by ultrasonication for 20 minutes, put them into a 100 mL polytetrafluoroethylene-lined reactor, react at 120° C. for 10 hours to obtain a mixed solution;

[0055] b. Filter the mixed solution obtained in step a with a 0.22 micron needle filter, dialyze for 24 hours with a dialysis bag with a molecular weight cutoff of 500-1000, and freeze-dry to obtain a series of surface amino group content o-phenylenediamine / polyethyleneimine 3 Carbonized polymer dots;

[0056] o-phenylenediamine / polyethyleneimine 3 Preparation of carbonized polymer dot sensing reagents:

[0057] c. The o-phenylenediamine / polyethyleneimine obtained in step b 3 The carbonized polymer dots were dissolved in a mixed solvent of methanol and N,N-dimethylformamide in a volume ratio of 1:3 to obtain o-phenylenediamine / polyethyleneimine. 3 Carbonized polymer dot sensing reagents.

[0058] The composition analysis of the o-phenylenediamine / polyethyleneimine carbonized polymer dot sensing reagents obtained in Examples 1-3 was performed. Figure 1 .

[0059] Example 4

[0060] Fluorescence spectra of a series of o-phenylenediamine / polyethyleneimine carbonized polymer dot sensing reagents reacting with 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP):

[0061] Take the series of o-phenylenediamine / polyethyleneimine carbonized polymer dot sensing reagents in Examples 1-3, add 30L of 5mg / mL 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) solutions, respectively, and perform fluorescence spectrum test after the reaction. Under the condition of excitation wavelength of 365nm, the fluorescence spectrum is measured. Figure 2 As shown, the fluorescence intensity of both is weakened, and the peak position of the fluorescence spectrum of 2,4,6-trinitrotoluene (TNT) is red-shifted.

[0062] Example 5

[0063] o-phenylenediamine / polyethyleneimine 1 Fluorescence spectrum of carbonized polymer dot sensing material reagent at 553nm after reaction with 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) solution:

[0064] Take the o-phenylenediamine / polyethyleneimine in Example 1 1 Carbonized polymer dot sensing reagents were added with 30L of 0-2mg / mL 2,4,6-trinitrotoluene (TNT) solution and 0-500μg / mL 2,4,6-trinitrophenol (TNP) solution, respectively. After the reaction, fluorescence spectrum test was performed. Under the condition of excitation wavelength of 365nm, the fluorescence spectrum and ultraviolet absorption spectrum were measured for 2,4,6-trinitrotoluene (TNT). Figure 3 As shown in the figure, with the increase of TNT concentration, the fluorescence intensity at 553nm gradually weakened, the fluorescence spectrum gradually shifted to 590nm, and the absorbance of the ultraviolet absorption spectrum at 466nm gradually increased. Figure 4 As shown, as the concentration of TNP increases, the fluorescence is gradually quenched, and the absorbance at 376 nm in the UV absorption spectrum gradually increases.

[0065] Example 6

[0066] o-phenylenediamine / polyethyleneimine 1 Relationship between the fluorescence intensity at 553nm and the concentration of 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) after the carbonized polymer dot sensing material reagent reacts with 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) solution:

[0067] Take the o-phenylenediamine / polyethyleneimine prepared in Example 1 1 The carbonized polymer dot sensing reagent was configured to a concentration of 0.1 mg / mL. 270 μL of the solution was taken into a fluorescence cuvette, and 30 μL of 1-2 mg / mL 2,4,6-trinitrotoluene (TNT) and 0-500 μg / mL 2,4,6-trinitrophenol (TNP) aqueous solutions were added respectively. After the reaction, the fluorescence spectrum and ultraviolet absorption spectrum were tested. For the fluorescence spectrum, the fluorescence emission intensity of the solution at 533 nm was compared with the concentrations of 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) to make a standard graph. According to the fluorescence spectrum standard graph as shown in the figure Figure 5 As shown in the figure, it can be seen that with the increase of 2,4,6-trinitrotoluene (TNT) concentration, the fluorescence emission intensity at 533nm presents two different decreasing rates, and both show a good linear relationship. Using the formula LOD = 3σ / K (K tnt =110035,σ tnt =2.7; K tnp =1677,σ tnp=2.7) the detection limit calculated is 324nM, 21.08nM; for the ultraviolet absorption spectrum for TNT, the ratio of the absorbance of the solution at 466nm to 376nm and the concentration of TNT is used as a standard graph, according to the ultraviolet absorption spectrum standard graph as shown Figure 6 As shown in a, it can be seen that with the increase of TNT concentration, A 466nm / A 376nm The absorbance at the position shows an increasing rate and a good linear relationship. Using the formula LOD = 3σ / K (K tnt =0.30147,σ tnt =0.00586) is 255M; for 2,4,6-trinitrophenol (TNP), the absorbance of the solution at 376nm and the concentration of TNP are used as a standard graph. According to the UV absorption spectrum standard graph, Figure 6 As shown in b, it can be seen that with the increase of TNP concentration, the absorbance at 376nm shows an increasing rate and a good linear relationship. Using the formula LOD = 3σ / K (K tnp =0.04944,σ tnp =0.00121) and the detection limit was calculated to be 318.6 nM.

[0068] Example 7

[0069] o-phenylenediamine / polyethyleneimine 1 Fluorescence response time of carbonized polymer dot sensing material reagent and 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) solution:

[0070] Take the o-phenylenediamine / polyethyleneimine prepared in Example 1 1 Carbonized polymer dots (OPD / PEI 1 CPDs) sensing material, prepared at a concentration of 0.1 mg / mL, took 270 μL of the solution in a fluorescence cuvette, added 30 μL of 10 mg / mL 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) aqueous solutions, respectively, with the increase of 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) concentrations, and made a scatter plot of the fluorescence emission intensity of the solution at 533 nm and the reaction time, as shown in the figure. Figure 7 As shown in a, the response time is less than 10s.

[0071] Example 8

[0072] OPD / PEI 1 Colorimetric response time of CPDs) sensing material reagent and 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) solution:

[0073] Take the o-phenylenediamine / polyethyleneimine prepared in Example 1 1 The concentration of carbonized polymer dot sensing material was 0.1 mg / mL. 270 μL of the solution was taken into a fluorescent cuvette, and 30 μL of 10 mg / mL 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) aqueous solutions were added respectively. A digital camera was used to take pictures, and the RGB values ​​were extracted. A scatter plot of RGB and reaction time was made, as shown in Figure 2. Figure 7 As shown in b, the response time is less than 1s.

[0074] Example 9

[0075] o-phenylenediamine / polyethyleneimine 1 Fluorescence-specific detection and recognition of 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) by carbonized polymer dot sensing material reagents:

[0076] Take the o-phenylenediamine / polyethyleneimine prepared in Example 1 1 Carbonized polymer dot sensing material, prepared at a concentration of 0.1 mg / mL, take 270 μL of 0.1 mg / mL o-phenylenediamine / polyethyleneimine 1 Carbonized polymer dot sensing materials were mixed with 30 μL of 70.4 mM 2,4,6-trinitrotoluene (TNT), 2,4,6-trinitrophenol (TNP), 2,4-dinitrotoluene (DNT), m-dinitrobenzene (m-DNB), o-nitrobenzoic acid (2-NA), toluene (MB), p-xylene (1,4-DMB), o-phthalonitrile (1,2-DCB), xylene isomers (DMB), p-toluenesulfonic acid (4-TSA), benzoic acid (BNE), CaCl 2 ,Gd(NO 3 ) 3 、AlCl 3 、KSCN、Ti(SO 4 ) 2 、(CH3COO) 2 After the reaction of Zn, LiCl, NaI, starch (Starch) and flour (Flour) aqueous solution, the fluorescence spectrum was tested after the reaction, such as Figure 8 a shows o-phenylenediamine / polyethyleneimine 1 The carbonized polymer dot sensing reagent had no obvious change in fluorescence to other interferents, indicating that the sensing reagent had good specificity for the detection of 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP).

[0077] Example 10

[0078] o-Phenylenediamine / Polyethyleneimine 1 Colorimetric Specific Detection and Recognition of TNT and TNP by Carbopolymers Dots Sensing Material Reagent

[0079] Take the o-phenylenediamine / polyethyleneimine carbopolymers dots sensing material reagent prepared in Example 1 1 Prepare a carbopolymers dots sensing material reagent with a concentration of 0.1 mg / mL. Take 270 μL of the o-phenylenediamine / polyethyleneimine carbopolymers dots sensing material reagent with a concentration of 0.1 mg / mL 1 Carbopolymers dots sensing material reagent, and react it with 30 μL of 2,4,6-trinitrotoluene (TNT), 2,4,6-trinitrophenol (TNP), 2,4-dinitrotoluene (DNT), m-dinitrobenzene (m-DNB), o-nitrobenzoic acid (2-NA), toluene (MB), p-xylene (1,4-DMB), o-phthalonitrile (1,2-DCB), xylene isomers (DMB), p-toluenesulfonic acid (4-TSA), benzoic acid (BNE), CaCl 2 、Gd(NO 3 ) 3 、AlCl 3 、KSCN、Ti(SO 4 ) 2 、(CH3COO) 2 Zn、LiCl、NaI, aqueous solutions of starch and flour respectively. After the reaction, perform ultraviolet absorption spectroscopy on the fluorescence spectrogram, as Figure 8 shown in b, the o-phenylenediamine / polyethyleneimine 1 carbopolymers dots sensing material reagent shows no obvious color change for other interfering substances, indicating that the sensing material reagent has good specificity for the detection of 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP).

[0080] Example 11

[0081] o-Phenylenediamine / Polyethyleneimine 1 Preparation of Paper-based Sensing Material Loaded with o-Phenylenediamine / Polyethyleneimine Carbopolymers Dots

[0082] Select a commercial filter paper with an area of 4 cm 2 , soak it in the o-phenylenediamine / polyethyleneimine carbopolymers dots sensing reagent obtained in Example 1 1 , take it out after 1 minute to obtain a paper-based sensing material loaded with o-phenylenediamine / polyethyleneimine 1 carbopolymers dots;

[0083] o-Phenylenediamine / Polyethyleneimine 1Carbonized polymer dot-loaded paper-based sensing material distinguishes and identifies 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) solid particles:

[0084] 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) particles were sprayed onto the obtained o-phenylenediamine / polyethyleneimine 1 On the paper-based sensing material loaded with carbonized polymer dots, the fluorescence color change was observed by naked eyes under the condition of excitation wavelength of 365nm, such as Fig. 9 As shown in a, TNT changes from yellow-green to red-brown; Fig. 9 b shows that the TNP changes from yellow-green to dark green.

[0085] Example 12

[0086] o-phenylenediamine / polyethyleneimine 1 Carbonized polymer dot-loaded paper-based sensing material distinguishes and identifies 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) atmospheres:

[0087] Weigh 0.0100 g of 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) solid particles and place them in small bottles. 1 The carbonized polymer dot-loaded paper-based sensing material was placed in a bottle, and the vial was placed in an oven at 50°C, 60°C, 70°C, and 80°C to prepare 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) atmospheres. Under an excitation wavelength of 365 nm, the naked eye was used to observe the Fig.10 The fluorescence color of TNT shown in a changes from yellow-green to red-brown; Fig.10 The fluorescence color of TNP shown in b changes from yellow-green to colorless and then to yellow-green.

Claims

1. A method for controlling the surface amine content of o-phenylenediamine / polyethyleneimine carbonized polymer dots, characterized in that Follow these steps: Preparation of a series of o-phenylenediamine / polyethyleneimine carbonized polymer dots: a. Mix 0.108 g of o-phenylenediamine with 0.108 g, 0.054 g, and 0.036 g of polyethyleneimine, 0.8 mL of 20% hydrogen peroxide, and 1.48 mL of 2M hydrochloric acid, add them to 50 mL of deionized water, mix them evenly by ultrasonication for 20 minutes, put them into a 100 mL polytetrafluoroethylene-lined reactor, react at 120 ° C for 10 hours, and obtain a mixed solution; b. filtering the mixed solution obtained in step a through a 0.22 μm needle filter, dialyzing it through a dialysis bag with a molecular weight cutoff of 500-1000 for 24 h, and freeze-drying it to obtain a series of o-phenylenediamine / polyethyleneimine carbonized polymer dots, namely, o-phenylenediamine / polyethyleneimine 1 carbonized polymer dots, o-phenylenediamine / polyethyleneimine 2 carbonized polymer dots, or o-phenylenediamine / polyethyleneimine 3 carbonized polymer dots; Preparation of a series of o-phenylenediamine / polyethyleneimine carbonized polymer dot sensing reagents: c. Dissolve the series of o-phenylenediamine / polyethyleneimine carbonized polymer dots obtained in step b in a mixed solvent of methanol and N,N-dimethylformamide in a volume ratio of 1:3 to obtain a series of o-phenylenediamine / polyethyleneimine carbonized polymer dot sensing reagents, namely, o-phenylenediamine / polyethyleneimine 1 carbonized polymer dot sensing reagent, o-phenylenediamine / polyethyleneimine 2 carbonized polymer dot sensing reagent or o-phenylenediamine / polyethyleneimine 3 carbonized polymer dot sensing reagent.

2. The o-phenylenediamine / polyethyleneimine carbonized polymer dot sensing reagent obtained by the method of claim 1 is used to prepare 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol solutions for detection, characterized in that Follow these steps: Detection of 2,4,6-trinitrotoluene solution by o-phenylenediamine / polyethyleneimine carbonized polymer dot sensing reagent: A 5 mg / mL 2,4,6-trinitrotoluene solution was added to the obtained o-phenylenediamine / polyethyleneimine 1 carbonized polymer dots, o-phenylenediamine / polyethyleneimine 2 carbonized polymer dots or o-phenylenediamine / polyethyleneimine 3 carbonized polymer dots sensing reagents, and the fluorescence spectrum and the ultraviolet absorption spectrum were measured under the condition of an excitation wavelength of 365 nm; A 0-2 mg / mL 2,4,6-trinitrotoluene solution was added to the obtained o-phenylenediamine / polyethyleneimine 1 carbonized polymer dot sensing reagent, and the fluorescence spectrum and ultraviolet absorption spectrum were measured under the condition of an excitation wavelength of 365 nm. 2,4,6-trinitrotoluene and o-phenylenediamine / polyethyleneimine carbonized polymer dots formed a Meisenheimer complex, which changed the colorimetric color from colorless to reddish brown. The fluorescence resonance energy transfer between the Meisenheimer complex and the 2,4,6-trinitrotoluene molecules caused the fluorescence color to gradually change from yellow to light yellow, accompanied by a red shift in the peak position. Detection of 2,4,6-trinitrophenol solution by o-phenylenediamine / polyethyleneimine carbonized polymer dot sensing reagent: A 5 mg / mL 2,4,6-trinitrophenol solution was added to the obtained o-phenylenediamine / polyethyleneimine 1 carbonized polymer dots, o-phenylenediamine / polyethyleneimine 2 carbonized polymer dots or o-phenylenediamine / polyethyleneimine 3 carbonized polymer dots sensing reagents, and the fluorescence spectrum and the ultraviolet absorption spectrum were measured under the condition of an excitation wavelength of 365 nm; A 0-500 mg / mL 2,4,6-trinitrophenol solution was added to the obtained o-phenylenediamine / polyethyleneimine 1 carbonized polymer dot sensing reagent, and the fluorescence spectrum and ultraviolet absorption spectrum were measured under the condition of an excitation wavelength of 365 nm. Under colorimetric conditions, the color changed from colorless to yellow-green. The electron transfer between molecules caused the fluorescence color of 2,4,6-trinitrophenol to change from yellow to colorless.

3. The carbonized polymer dot sensing reagent of o-phenylenediamine / polyethyleneimine 1 obtained by the method of claim 1 is used to prepare solid particles of 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol and detect the atmosphere, and the specific operation is carried out according to the following steps: Preparation of paper-based sensing materials loaded with o-phenylenediamine / polyethyleneimine 1 carbonized polymer dots: a. Select an area of ​​4cm 2 commercial filter paper, soaking it in the obtained o-phenylenediamine / polyethyleneimine 1 carbonized polymer dot sensing reagent, and taking it out after 1 minute to obtain the o-phenylenediamine / polyethyleneimine 1 carbonized polymer dot-loaded paper-based sensing material; Detection of 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol solid particles by paper-based sensing materials loaded with o-phenylenediamine / polyethyleneimine 1 carbonized polymer dots: b. Spraying 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol particles onto the o-phenylenediamine / polyethyleneimine 1 carbonized polymer dot paper-based sensing material obtained in step a, respectively. Under the condition of an excitation wavelength of 365 nm, the fluorescence color change is observed by naked eyes: 2,4,6-trinitrotoluene changes from yellow-green to reddish brown; 2,4,6-trinitrophenol changes from yellow-green to dark green; Detection of 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol atmosphere by paper-based sensing material loaded with o-phenylenediamine / polyethyleneimine 1 carbonized polymer dots: c. Weigh 0.0100 g of 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol solid particles and place them in small bottles respectively. Place the paper-based sensing material of o-phenylenediamine / polyethyleneimine 1 carbonized polymer dots obtained in step a in the bottle and seal it. Place the small bottle in an oven at 50°C, 60°C, 70°C or 80°C to prepare 2,4,6-trinitrotoluene and 2,4,6-trinitrophenol atmospheres. Under the excitation wavelength of 365 nm, the fluorescence color of 2,4,6-trinitrotoluene changes from yellow-green to reddish brown when observed with the naked eye; the fluorescence color of 2,4,6-trinitrophenol changes from yellow-green to colorless and then to yellow-green.

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