Application of organic luminescent free radical materials in gas phase fluorescence detection of nerve agents, fluorescent films and their applications

Abstract

The present invention provides an application of an organic luminescent free radical material in gas phase fluorescence detection of nerve agents, a fluorescent film and the application thereof, and belongs to the field of fluorescence sensing technology. The organic luminescent free radical material having a structure shown in Formula I in the present invention belongs to a trityl free radical or diphenylmethyl free radical series, has a high fluorescence quantum yield and excellent photostability, is very suitable for use as a fluorescent probe, and can be used for gas phase fluorescence detection of nerve agents, especially the fluorescent film based on the organic luminescent free radical material having a structure shown in Formula I can realize real-time, efficient, and visualized DCP gas phase detection, and the detection limit is lower than the IDLH value of sarin.

Description

Technical Field

[0001] The present invention relates to the field of fluorescence sensing technology, and in particular to the application of organic luminescent free radical materials in gas phase fluorescence detection of nerve agents, fluorescent films and applications thereof. Background Art

[0002] Sarin is a highly toxic organic phosphonate and a type of nerve agent. Its scientific name is isopropyl methyl fluorophosphonate. At room temperature, sarin is a colorless liquid, and pure sarin has almost no odor. Sarin enters the human body mainly through the respiratory system and causes an increase in acetylcholine in the body. The main symptoms of sarin poisoning include difficulty breathing, drooling and sweating, nausea, vomiting, etc. Sarin is extremely toxic, and its rapid risk of endangering life and health (IDLH value) is 7ppb. Inhaling a sufficient amount of sarin can cause death within a few minutes. Therefore, it is very necessary to develop a method for rapid and efficient detection of sarin.

[0003] Since sarin is extremely toxic, its detection can only be carried out in laboratories authorized by the Office for the Prohibition of Chemical Weapons. Therefore, researchers generally use diethyl chlorophosphate (DCP), which has a chemical structure similar to sarin but is less toxic, as a sarin simulant for related research. So far, the methods for detecting DCP mainly include mass spectrometry, enzyme-based biosensor, electrochemical method and surface acoustic wave sensor. However, these methods have slow response speed, complex operation, poor selectivity, and require large equipment, making it impossible to achieve rapid on-site detection. Fluorescence sensing has the characteristics of fast response speed, high sensitivity, and miniaturization of instruments and equipment. It is one of the most promising methods for rapid on-site detection.

[0004] At present, researchers have reported some fluorescent probes for DCP detection, but some fluorescent probes have poor photostability (Anal. Chem. 2018, 90, 7131-7134; Anal. Chem. 2019, 91, 1711-1714), and are mostly used for DCP liquid phase detection (New J. Chem., 2017, 41, 1653; J. Hazard. Mater., 2018, 342, 10-19), and rarely involve DCP gas phase detection. DCP mainly enters the human body through the respiratory tract, so the development of fluorescent probes with excellent photostability and suitable for DCP gas phase detection has more practical application prospects. Summary of the invention

[0005] The purpose of the present invention is to provide an application of an organic luminescent free radical material in gas-phase fluorescence detection of nerve agents, a fluorescent film and its application. The organic luminescent free radical material having a structure shown in Formula I in the present invention has a high fluorescence quantum yield and excellent photostability, and can be used for gas-phase fluorescence detection of nerve agents. In particular, the fluorescent film based on the organic luminescent free radical material having a structure shown in Formula I can realize real-time, efficient and visualized DCP gas-phase detection.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides an application of an organic luminescent free radical material in gas phase fluorescence detection of nerve agents, wherein the organic luminescent free radical material has a structure shown in Formula I:

[0008] DR Formula I;

[0009] In the formula I, R is a trityl free radical or a diphenylmethyl free radical, and D is a carbazoline group.

[0010] Preferably, the trityl free radical has a structure shown in Formula II, and the diphenylmethyl free radical has a structure shown in Formula III:

[0011]

[0012] Preferably, the carbazoline group has a structure shown in Formula IV-1, Formula IV-2, Formula IV-3 or Formula IV-4:

[0013]

[0014] Preferably, the organic light-emitting free radical material has a structure shown in Formula R1 or Formula R2:

[0015]

[0016] Preferably, the nerve agent comprises isopropyl methylphosphonofluoroate and / or an isopropyl methylphosphonofluoroate mimetic.

[0017] The present invention provides a fluorescent film, the preparation raw materials of which include a matrix material, a guest material and an organic solvent; the guest material is an organic luminescent free radical material having a structure shown in Formula I:

[0018] DR Formula I.

[0019] Preferably, the matrix material comprises polystyrene, polymethyl methacrylate, polycarbonate or polyvinyl chloride.

[0020] Preferably, the mass ratio of the guest material to the matrix material is 1:(9-99).

[0021] Preferably, the organic solvent comprises toluene, chlorobenzene, chloroform, dichloromethane, tetrahydrofuran or o-dichlorobenzene.

[0022] The present invention provides the use of the fluorescent film described in the above technical solution or the fluorescent film prepared by the preparation method described in the above technical solution in gas phase fluorescence detection of nerve agents.

[0023] The present invention provides an application of an organic luminescent free radical material having a structure shown in Formula I in gas phase fluorescence detection of nerve agents. The organic luminescent free radical material having a structure shown in Formula I in the present invention belongs to the trityl free radical or diphenylmethyl free radical series, has a high fluorescence quantum yield and excellent photostability, is very suitable for use as a fluorescent probe, and can be used for gas phase fluorescence detection of nerve agents, especially the fluorescent film based on the organic luminescent free radical material having a structure shown in Formula I can realize real-time, efficient, and visualized DCP gas phase detection. Specifically, when the fluorescent film of the present invention is placed in DCP gas, the fluorescent film contacts the DCP gas, the free radical molecules react with the DCP, and the fluorescence emission of the fluorescent film is rapidly and significantly quenched and blue-shifted. Under ultraviolet light excitation, the naked eye can observe that the emission color of the fluorescent film changes from red to orange, and the emission intensity is significantly weakened, realizing real-time, efficient, and visualized detection of DCP gas, and the detection limit is lower than the IDLH value of sarin. The detection mechanism of the fluorescent film provided by the present invention is that the protonation of the free radical causes the transition of the first excited state of the free radical and the flipping of the electron cloud distribution between the donor and the acceptor, and it is this transition that brings about a unique fluorescence emission blue shift. In addition, the fluorescent film provided by the present invention can still quickly distinguish DCP vapor in the presence of a variety of organic phosphine compound vapors and organic solvent vapors, has excellent selectivity and anti-interference ability, and still has a high fluorescence quenching rate after repeated use. Compared with liquid phase detection, which needs to be carried out in a homogeneous solution system, the fluorescent film used for gas phase detection in the present invention has the advantages of no pollution to the object to be detected, good repeatability, and easy implantation in portable devices.

[0024] In addition, the present invention provides a method for preparing the fluorescent film, which is simple to operate, low in cost and highly universal. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The absorption and emission spectra of R1 (organic light-emitting free radical material having a structure shown in formula R1) solution and the emission spectrum of R1 fluorescent film, the absorption and emission spectra of R2 (organic light-emitting free radical material having a structure shown in formula R2) solution and the emission spectrum of R2 fluorescent film, and the photostability result graphs of R1 solution and R2 solution;

[0026] Figure 2 is the fluorescence spectrum of R1 fluorescent film in DCP vapor changing with time;

[0027] Figure 3 is the fluorescence spectrum of R2 fluorescent film in DCP vapor changing with time;

[0028] Figure 4 The fluorescence quenching rate of R1 fluorescent film in different concentrations of DCP vapor is shown in the figure;

[0029] Figure 5 The fluorescence quenching rate of R2 fluorescent film in different concentrations of DCP vapor is shown in the figure;

[0030] Figure 6 The bar graphs are the fluorescence change rates of the R1 fluorescent film exposed to various organic phosphine compounds (DCP, DMMP, DCNP, TEPPM) or organic solvents (n-hexane, toluene, ethanol) gases;

[0031] Figure 7 The bar graphs are the fluorescence change rates of the R2 fluorescent film exposed to various organic phosphine compounds (DCP, DMMP, DCNP, TEP, PM) or organic solvent gases (n-hexane, toluene, ethanol);

[0032] Figure 8 The fluorescence spectra of the R1 fluorescent film when simultaneously exposed to a mixed saturated vapor of various organic phosphine compounds (DCP, DMMP, DCNP, TEP, PM) and organic solvents (n-hexane, toluene, ethanol) and after adding DCP vapor to the mixed saturated vapor;

[0033] Fig. 9 The fluorescence spectra of the R2 fluorescent film when it is simultaneously exposed to a mixed saturated vapor of multiple organic phosphine compounds (DCP, DMMP, DCNP, TEP, PM) and organic solvents (n-hexane, toluene, ethanol) and after DCP vapor is added to the mixed vapor;

[0034] Fig.10 This is the test result of the cyclicity of R1 fluorescent film;

[0035] Fig.11 This is the result of the cyclic test of the R2 fluorescent film;

[0036] Fig.12 The diagram is a schematic diagram of the mechanism of the organic light-emitting free radical material R1 and the organic light-emitting free radical material R2 detecting DCP, and the absorption spectrum, fluorescence lifetime decay curve and electron spin resonance result diagram;

[0037] Fig.13 This is a graph showing the theoretical calculation results of the organic light-emitting free radical material R1 and the organic light-emitting free radical material R2 before and after DCP testing. DETAILED DESCRIPTION

[0038] The present invention provides an application of an organic luminescent free radical material in gas phase fluorescence detection of nerve agents, wherein the organic luminescent free radical material has a structure shown in Formula I:

[0039] DR Formula I;

[0040] In the formula I, R is a trityl free radical or a diphenylmethyl free radical, and D is a carbazoline group.

[0041] In the present invention, the trityl free radical preferably has a structure shown in Formula II, and the diphenylmethyl free radical preferably has a structure shown in Formula III:

[0042]

[0043] In the present invention, the carbazoline group preferably has a structure shown in Formula IV-1, Formula IV-2, Formula IV-3 or Formula IV-4:

[0044]

[0045]

[0046] In the present invention, the organic light-emitting free radical material preferably has a structure shown in Formula R1 or Formula R2:

[0047]

[0048] In the present invention, the nerve agent preferably includes isopropyl methylphosphonofluoroate (sarin) and / or isopropyl methylphosphonofluoroate simulants, and the isopropyl methylphosphonofluoroate simulants preferably include diethyl chlorophosphate (DCP).

[0049] The present invention provides a fluorescent film, the preparation raw materials of which include a matrix material, a guest material and an organic solvent; the guest material is an organic luminescent free radical material having a structure shown in Formula I:

[0050] DR Formula I.

[0051] In the present invention, the organic light-emitting free radical material used as the guest material has a structure shown in Formula I. The optional range of the types of the D group and the R group in Formula I is preferably consistent with the above scheme, which will not be repeated here. The optional types of the organic light-emitting free radical material are preferably consistent with the above scheme, which will not be repeated here.

[0052] In the present invention, the matrix material preferably includes polystyrene, polymethyl methacrylate, polycarbonate or polyvinyl chloride, and more preferably polymethyl methacrylate. In the present invention, the mass ratio of the guest material to the matrix material is preferably 1: (9-99), more preferably 1: (15-50), and further preferably 1: (19-25). The matrix material in the present invention can disperse the guest material, ensuring that the fluorescent film has good fluorescent luminescence performance.

[0053] In the present invention, the organic solvent preferably includes toluene, chlorobenzene, chloroform, dichloromethane, tetrahydrofuran or o-dichlorobenzene, and more preferably o-dichlorobenzene. In the present invention, the volume ratio of the total mass of the matrix material and the guest material to the organic solvent is preferably (0.5-50) mg:1 mL, more preferably (5-30) mg:1 mL, and further preferably (10-20) mg:1 mL.

[0054] The present invention provides a method for preparing the fluorescent film described in the above technical solution, comprising the following steps:

[0055] The matrix material, the guest material and the organic solvent are mixed to form a film to obtain a fluorescent film.

[0056] The present invention mixes the matrix material, the guest material and the organic solvent to obtain a mixed material. The present invention has no special limitation on the mixing method of the matrix material, the guest material and the organic solvent, and a method well known to those skilled in the art can be used to achieve sufficient mixing of the materials.

[0057] After obtaining the mixed material, the present invention forms a film of the mixed material to obtain a fluorescent film. In the present invention, the film forming method preferably includes:

[0058] The mixed material is coated on one side of a substrate, and after drying, a fluorescent film is obtained on the one side of the substrate.

[0059] In the present invention, the substrate is preferably a transparent substrate, and the transparent substrate preferably includes a glass substrate, and the glass substrate preferably includes a quartz glass substrate or an ITO glass substrate, and more preferably a quartz glass substrate. In the present invention, the substrate is preferably cleaned and pretreated before use to remove impurities on its surface; the cleaning pretreatment method is preferably ultrasonic cleaning, and the cleaning liquid used in the ultrasonic cleaning preferably includes water, ethanol, acetone and toluene in sequence; the ultrasonic cleaning time of each cleaning liquid is preferably 25 to 35 minutes, and more preferably 30 minutes. In the present invention, the coating method is preferably spin coating; the rotation speed of the spin coating is preferably 1000 to 2200 r / min, and more preferably 1500 to 2000 r / min; the spin coating time is preferably 25 to 35 seconds, and more preferably 28 to 30 seconds. In the present invention, the mixed material is preferably dripped onto a single side of the substrate, and then the spin coating is performed using a glue spreader. The present invention does not specifically limit the drying method, and sufficient drying can be achieved. In the present invention, the drying method preferably includes natural drying at room temperature or vacuum drying, preferably vacuum drying; the vacuum drying temperature is preferably 40-50°C, more preferably 45°C, and the vacuum drying time is preferably 10-70 minutes, more preferably 30-60 minutes. The present invention has no special limitation on the thickness of the fluorescent film, and a thickness familiar to those skilled in the art can be used; in the present invention, the thickness of the fluorescent film is preferably 50-150nm.

[0060] The present invention provides the use of the fluorescent film described in the above technical solution or the fluorescent film prepared by the preparation method described in the above technical solution in the gas phase fluorescence detection of nerve agents. In the present invention, the optional types of nerve agents are preferably consistent with the above technical solution, which will not be repeated here. Based on the fluorescent film described in the present invention, real-time, efficient and visual gas phase detection of nerve agents can be achieved. Specifically, taking the detection of DCP as an example, when the fluorescent film described in the present invention is placed in DCP gas, the fluorescent film contacts the DCP gas, the free radical molecules react with DCP, and the fluorescence emission of the fluorescent film is rapidly and significantly quenched and blue-shifted. Under the excitation of ultraviolet light, the naked eye can observe that the emission color of the fluorescent film changes from red to orange, and the emission intensity is significantly weakened, thereby achieving real-time, efficient and visual detection of DCP gas, and the detection limit is lower than the IDLH value of sarin.

[0061] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0062] Example 1

[0063] The steps of preparing a fluorescent film based on an organic light-emitting free radical material R1 (having a structure shown in formula R1) are as follows:

[0064] 1 mg of organic light-emitting free radical material R1 and 19 mg of polymethyl methacrylate were dissolved in 1 mL of o-dichlorobenzene to obtain a mixed liquid; the quartz glass was ultrasonically cleaned with water, ethanol, acetone and toluene for 30 min respectively to remove impurities on the surface of the quartz glass; 60 μL of the mixed liquid was added dropwise to the cleaned quartz glass surface, and a film was formed by spin coating using a coater, the speed of the coater was 2000 r / min, and the spin coating time was 30 s; and then vacuum dried at 45° C. for 60 min to obtain a fluorescent film based on the organic light-emitting free radical material R1, which was recorded as R1 fluorescent film.

[0065] Example 2

[0066] The method of Example 1 is followed, except that the organic light-emitting free radical material R1 is replaced by an organic light-emitting free radical material R2 (having a structure shown in formula R2), and finally a fluorescent film based on the organic light-emitting free radical material R2 is prepared, which is referred to as R2 fluorescent film.

[0067] Test Example 1

[0068] The organic light-emitting free radical material R1 and the organic light-emitting free radical material R2 are dissolved in dichloromethane to obtain R1 solution and R2 solution, respectively, and the absorption and emission spectra of the R1 solution and R2 solution are tested. -5 M, the excitation wavelength is 375nm, and the emission spectra of the R1 fluorescent film and the R2 fluorescent film are compared, and the light stability of the R1 solution and the R2 solution are tested. The results are as follows Figure 1 shown. Figure 1 (a) is the absorption and emission spectrum of R1 solution and the emission spectrum of R1 fluorescent film, (b) is the absorption and emission spectrum of R2 solution and the emission spectrum of R2 fluorescent film, (c) is the photostability result diagram of R1 solution and R2 solution. Figure 1 It can be seen that the emission of R1 solution and R2 solution are both red light emission, and the maximum emission peaks are located at 645nm and 648nm respectively. The R1 fluorescent film and R2 fluorescent film were excited by 375nm wavelength light. The results showed that the R1 fluorescent film and R2 fluorescent film also have obvious red light emission, among which the maximum emission wavelengths of R1 fluorescent film and R2 fluorescent film are 631nm and 657nm respectively. At the same time, a 355nm pulsed laser (energy density of 61.4kW / cm 2, pulse width of 8ns, frequency of 10Hz) to excite R1 solution and R2 solution and collect the intensity at the maximum emission wavelength of the two solutions. The half-lives of the two solutions were calculated to be 1.17×10 4 s and 9.10×10 5 s. This excellent photostability indicates that the organic light-emitting free radical material R1 and the organic light-emitting free radical material R2 are very suitable for use as fluorescent probes.

[0069] Test Example 2

[0070] The R1 fluorescent film was placed in DCP vapor, and the changes in the fluorescence emission spectrum were recorded using a fluorescence spectrometer. Figure 2 is the fluorescence spectrum of R1 fluorescent film in DCP vapor over time, Figure 2 It can be seen that the fluorescence intensity weakened and blue-shifted within 40s, and the fluorescence emission spectrum blue-shifted from 631nm to 581nm, and at the same time, the emission of the R1 fluorescent film changed from red light visible to the naked eye to orange light. This shows that the R1 fluorescent film can be used to detect sarin or its simulant DCP gas. Specifically, the R1 fluorescent film is placed in the gas to be tested, and the fluorescence emission spectrum changes are recorded using a fluorescence spectrometer. If the fluorescence intensity weakens and blue-shifts within a short time (40s) (the fluorescence emission spectrum blue-shifts from 631nm to 581nm), and at the same time, the R1 fluorescent film emission changes from red light visible to the naked eye to orange light, it means that the gas to be tested contains sarin or its simulant DCP gas.

[0071] Similarly, the R2 fluorescent film was placed in DCP vapor, and the changes in the fluorescence emission spectrum were recorded using a fluorescence spectrometer. Figure 3 is the fluorescence spectrum of R2 fluorescent film in DCP vapor over time, Figure 3 It can be seen that the fluorescence intensity weakened and blue-shifted within 40s, and the fluorescence emission spectrum blue-shifted from 657nm to 590nm, and at the same time, the emission of the R2 fluorescent film changed from red light visible to the naked eye to orange light. This shows that the R2 fluorescent film can be used to detect sarin or its simulant DCP gas. Specifically, the R2 fluorescent film is placed in the gas to be tested, and the fluorescence emission spectrum changes are recorded using a fluorescence spectrometer. If the fluorescence intensity weakens and blue-shifts within a short time (40s) (the fluorescence emission spectrum blue-shifts from 657nm to 590nm), and at the same time, the R2 fluorescent film emission changes from red light visible to the naked eye to orange light, it means that the gas to be tested contains sarin or its simulant DCP gas.

[0072] Figure 4 The fluorescence quenching rate of R1 fluorescent film in different concentrations of DCP vapor is shown in the figure. Figure 4 It can be seen that the detection limit of R1 fluorescent film for DCP is 3.5 ppb, which is much lower than the IDLH value of sarin.

[0073] Figure 5 The fluorescence quenching rate of R2 fluorescent film in different concentrations of DCP vapor is shown in the figure. Figure 5 It can be seen that the detection limit of R2 fluorescent film for DCP is 2.7 ppb, which is much lower than the IDLH value of sarin.

[0074] Test Example 3

[0075] The emission spectrum of the R1 fluorescent film was collected using a fluorescence spectrometer, and then the fluorescence spectra of the R1 fluorescent film in the saturated vapor of dimethyl methyl phosphate (DMMP), diethyl cyanophosphate (DCNP), triethyl phosphate (TEP), methyl parathion (PM), n-hexane (HEX), toluene (Tol) and ethanol (EtOH) were collected respectively, and the fluorescence quenching rate of the R1 fluorescent film at its maximum emission wavelength was calculated. Figure 6 is a bar graph of the fluorescence change rate of the R1 fluorescent film when it is exposed to various organic phosphine compounds or saturated vapor of organic solvents; Figure 6 It can be seen that the fluorescence quenching rate of the R1 fluorescent film to DCP vapor is the highest, indicating that the R1 fluorescent film has good selectivity to DCP vapor.

[0076] Similarly, the emission spectrum of the R2 fluorescent film was collected using a fluorescence spectrometer, and then the fluorescence spectra of the R2 fluorescent film in the saturated vapor of dimethyl methyl phosphate (DMMP), diethyl cyanophosphate (DCNP), triethyl phosphate (TEP), methyl parathion (PM), n-hexane (HEX), toluene (Tol) and ethanol (EtOH) were collected respectively, and the fluorescence quenching rate of the R2 fluorescent film at its maximum emission wavelength was calculated. Figure 7 is a bar graph of the fluorescence change rate of the R2 fluorescent film when it is exposed to a variety of organic phosphine compounds or saturated vapor of organic solvents; Figure 7 It can be seen that the fluorescence quenching rate of the R2 fluorescent film to DCP vapor is the highest, indicating that the R2 fluorescent film has good selectivity to DCP vapor.

[0077] Test Example 4

[0078] The emission spectrum of the R1 fluorescent film was collected using a fluorescence spectrometer, and then the R1 fluorescent film was placed in a mixed saturated vapor of DMMP, DCNP, TEP, PM, n-hexane, toluene and ethanol to collect the emission spectrum, and finally DCP vapor was added to the mixed saturated vapor and the emission spectrum was collected. Figure 8 The fluorescence spectrum after simultaneously exposing the R1 fluorescent film to a mixed saturated vapor of multiple organic phosphine compounds and organic solvents and adding DCP vapor to the mixed saturated vapor; Figure 8It can be seen that when the R1 fluorescent film is exposed to the mixed saturated vapor of multiple organic phosphine compounds and organic solvents at the same time, the fluorescence spectrum of the R1 fluorescent film is only slightly quenched, and there is no obvious shift; when DCP vapor is added to the mixed saturated vapor, the emission of the R1 fluorescent film is obviously blue-shifted and quenched. This shows that the R1 fluorescent film has a specific response only to DCP, and has no obvious fluorescence response to other vapors, and has excellent anti-interference.

[0079] Similarly, a fluorescence spectrometer is used to collect the emission spectrum of the R2 fluorescent film, and then the R2 fluorescent film is placed in a mixed saturated vapor of DMMP, DCNP, TEP, PM, n-hexane, toluene and ethanol to collect the emission spectrum, and finally DCP vapor is added to the mixed saturated vapor and the emission spectrum is collected. Fig. 9 The fluorescence spectrum after simultaneously exposing the R2 fluorescent film to a mixed saturated vapor of multiple organic phosphine compounds and organic solvents and adding DCP vapor to the mixed saturated vapor; Fig. 9 It can be seen that when the R2 fluorescent film is exposed to the mixed saturated vapor of multiple organic phosphine compounds and organic solvents at the same time, the fluorescence spectrum of the R2 fluorescent film is only slightly quenched, and there is no obvious shift; when DCP vapor is added to the mixed saturated vapor, the emission of the R2 fluorescent film is obviously blue-shifted and quenched. This shows that the R2 fluorescent film has a specific response only to DCP, and has no obvious fluorescence response to other vapors, and has excellent anti-interference properties.

[0080] Test Example 5

[0081] The emission spectrum of the R1 fluorescent film was collected using a fluorescence spectrometer, and then the R1 fluorescent film was placed in DCP vapor for 40 seconds, and its fluorescence spectrum was obviously blue-shifted and quenched; thereafter, the R1 fluorescent film was taken out, fumigated with triethylamine vapor for 10 seconds, and its emission spectrum was collected again. Fig.10 The test results of the cyclic performance of the R1 fluorescent film are shown in Figure 2. Fig.10 It can be seen that after 5 cycles, the R1 fluorescent film still has a high fluorescence quenching rate.

[0082] Similarly, the emission spectrum of the R2 fluorescent film was collected using a fluorescence spectrometer, and then the R2 fluorescent film was placed in DCP vapor for 40 seconds, and its fluorescence spectrum was obviously blue-shifted and quenched; then the R2 fluorescent film was taken out, fumigated with triethylamine vapor for 10 seconds, and its emission spectrum was collected again. Fig.11 The test results of the cyclic performance of R2 fluorescent film are shown in Figure 2. Fig.11 It can be seen that after 5 cycles, the R2 fluorescent film still has a high fluorescence quenching rate.

[0083] Test Example 6

[0084] The changes of R1 solution and R2 solution before and after the detection of DCP were tested by using an ultraviolet absorption spectrometer, a steady-state / transient fluorescence spectrometer (the fluorescence decay curve test used a pulsed laser as the excitation light source with a wavelength of 378.8 nm), and an electron spin resonance (EPR) instrument. The solvents of R1 solution and R2 solution were dichloromethane with a concentration of 10 -5 M, the added DCP was 100 μM. Fig.12 Schematic diagram of the mechanism of organic light-emitting free radical material R1 and organic light-emitting free radical material R2 detecting DCP, as well as absorption spectrum, fluorescence lifetime decay curve and electron spin resonance result diagram. Fig.12 (a) is a schematic diagram of the mechanism and absorption spectrum of the organic light-emitting free radical material R1 when detecting DCP, and (b) is a schematic diagram of the mechanism and absorption spectrum of the organic light-emitting free radical material R2 when detecting DCP. The results show that after adding DCP to the R1 solution and the R2 solution, the absorption originally located at 580nm is greatly weakened. According to the inventor's previous research, the absorption peak here is caused by the transition of the doublet ground state (D0) of the free radical to its doublet first excited state (D1). The change of the absorption peak here indicates that the ground state of the free radical has changed. Fig.12 (c) is the fluorescence lifetime decay curve of the organic light-emitting free radical material R1 before and after contact with DCP, and (d) is the fluorescence lifetime decay curve of the organic light-emitting free radical material R2 before and after contact with DCP. The structures show that after contact with DCP, D1 of the organic light-emitting free radical material R1 and the organic light-emitting free radical material R2 undergoes obvious changes. Fig.12 (e) is the electron spin resonance result diagram of the organic light-emitting free radical material R1 before and after contacting DCP, and (f) is the electron spin resonance result diagram of the organic light-emitting free radical material R2 before and after contacting DCP. The results show that before and after contacting DCP, the organic light-emitting free radical material R1 and the organic light-emitting free radical material R2 both have obvious single-electron fluorescence signals, indicating that their fluorescence before and after contacting DCP belongs to doublet luminescence.

[0085] Example 7

[0086] The theoretical calculations were completed using the commercial software Gaussian09 program package. The ground state configuration was optimized using the B3LYP / 6-31G(d,p) method in density functional theory (DFT), and the excited state was optimized using the B3LYP / 6-31G(d,p) method in time-dependent density functional theory (TD-DFT). Fig.13 The figure is a graph showing the theoretical calculation results of the organic light-emitting free radical material R1 and the organic light-emitting free radical material R2 before and after DCP detection. Fig.13It can be seen that the energy levels of the two protonated organic light-emitting free radical materials are significantly reduced, and the energy gap is widened, which leads to the blue shift of the emission spectrum. In addition, the dihedral angle between the donor and the acceptor in the protonated organic light-emitting free radical material is significantly increased, and the electron cloud distribution of the β-HOMO (171β) and β-SOMO (172β) of the protonated free radical has undergone a significant change. In the protonated organic light-emitting free radical, the tri(2,4,6-trichlorobenzyl)methyl radical (TTM) becomes an electron donor, while the original electron donor carbazoline is completely transformed into an electron acceptor. The transition of its first excited state is the transition between TTM and the protonated carbazoline group. This special electron cloud distribution and transition mode are very rare even in the field of light-emitting free radicals.

[0087] In summary, the method provided by the present invention is simple, fast, low-cost, and has a wide range of applications for preparing fluorescent films based on organic luminescent free radical materials; at the same time, the fluorescent film has the advantages of rapid response, high sensitivity, visualization, good selectivity, and unique mechanism for fluorescence detection of DCP. Therefore, the method for rapid detection of nerve agent sarin based on organic luminescent free radical materials provided by the present invention has great application potential.

[0088] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. Application of an organic luminescent free radical material in gas phase fluorescence detection of nerve agents, wherein the organic luminescent free radical material has a structure shown in Formula I: DR type I; In the formula I, R is a trityl radical or a diphenylmethyl radical, and D is a carbazoline group; The trityl free radical has a structure shown in Formula II, and the diphenylmethyl free radical has a structure shown in Formula III: The carbazoline group has a structure shown in Formula IV-1, Formula IV-2, Formula IV-3 or Formula IV-4: The nerve agent is isopropyl methylphosphonofluoroate and / or a simulant of isopropyl methylphosphonofluoroate, and the simulant of isopropyl methylphosphonofluoroate is diethyl chlorophosphate.

2. The use according to claim 1, characterized in that: The organic light-emitting free radical material has a structure shown in formula R1 or formula R2:

3. Application of a fluorescent film in gas phase fluorescence detection of nerve agents, wherein the nerve agent is isopropyl methylphosphonofluoroate and / or a simulant of isopropyl methylphosphonofluoroate, and the simulant of isopropyl methylphosphonofluoroate is diethyl chlorophosphate; the raw materials for preparing the fluorescent film include a matrix material, a guest material and an organic solvent; the guest material is an organic luminescent free radical material having a structure shown in Formula I: DR type I; In the formula I, R is a trityl radical or a diphenylmethyl radical, and D is a carbazoline group; The trityl free radical has a structure shown in Formula II, and the diphenylmethyl free radical has a structure shown in Formula III: The carbazoline group has a structure shown in Formula IV-1, Formula IV-2, Formula IV-3 or Formula IV-4: The matrix material is polystyrene, polymethyl methacrylate, polycarbonate or polyvinyl chloride; The organic solvent is toluene, chlorobenzene, chloroform, dichloromethane, tetrahydrofuran or o-dichlorobenzene.

4. The use according to claim 3, characterized in that: The mass ratio of the guest material to the matrix material is 1:(9-99).

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