O-hydroxyphenyl azole organic fluorescent molecule and detection method

Abstract

The invention provides an o-hydroxyphenyl azole organic fluorescent molecule and a detection method, a fluorescent probe with strong fluorescence and large Stokes shift can be obtained by designing an o-hydroxyphenyl azole molecule with an excited state intramolecular proton transfer (ESIPT) effect, and when a recognition group phenolic hydroxyl group of the probe reacts with DCP, the ESIPT process is inhibited, and the detection result shows that the fluorescent probe has high fluorescence and large Stokes shift. The fluorescence changes rapidly, DCP can be identified accurately, and interference of other acidic substances can be avoided to a great extent due to selective reactivity of hydroxyl. The detection method provided by the invention can rapidly and sensitively realize specific detection of the nerve agent and the simulant thereof in a solution and a gas phase. Implementation of the invention is of great significance to detection of nerve agents.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical analysis and detection, and specifically relates to a method for detecting o-hydroxyphenylazole organic fluorescent molecules and nerve agents or their simulants. Background Art

[0003] In recent years, although traditional nerve detection methods, such as chromatography, mass spectrometry, ion mobility spectrometry and Raman scattering, have high sensitivity and accuracy, they have disadvantages such as complex operation, long detection cycle and high equipment cost, which makes it difficult to meet the needs of rapid on-site detection. Fluorescence detection technology has been widely used in biology, medicine, environment and other fields due to its advantages such as high sensitivity, good selectivity, simple operation and fast detection speed. Applying fluorescence detection technology to nerve agent detection can effectively improve the speed and sensitivity of on-site detection and reduce detection costs.

[0004] Due to the control and high toxicity of nerve agents, in the field of nerve agent detection, simulants such as diethyl chlorophosphate (DCP) are usually used for testing and evaluation. At present, there is a certain foundation for the research on fluorescence detection methods for nerve agents and their simulants (X. Li, Y. Lv, S. Chang, et al. Anal. Chem., 2019, 91, 10927–10931; YJ Jung, et al Sensors and Actuators: B Chemical., 2020, 323, 128698; P. Zheng, Z. Cui, H. Liu, et al. Journal of Hazardous Materials., 2021, 415, 125619; CN117030643A; CN118165019A). Although these detection methods can achieve rapid and highly sensitive detection of nerve agents and their simulants, they mainly use fluorescent molecules with pyridine as the recognition group. They have fast detection speed and high sensitivity, but poor selectivity and are easily interfered by other acidic substances in the environment, affecting the specific recognition of nerve agents. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] The present invention provides an o-hydroxyphenylazole organic fluorescent molecule and a detection method to solve the technical problems of poor selectivity, long response time and low sensitivity in traditional methods for detecting nerve agents or their analogs.

[0007] (II) Technical solution

[0008] In order to solve the above technical problems, the present invention proposes an o-hydroxyphenylazole organic fluorescent molecule, the general structural formula of the o-hydroxyphenylazole organic fluorescent molecule is as follows:

[0009]

[0010] The mother core structure is formed by connecting the 2nd position of phenol and the 2nd position of azole, X=O, S, NCH3; n=0-2; Ar is an aromatic ring or a heteroaromatic ring, and the connection point of Ar is the 4th or 5th position of the azole ring, or the 3rd to 6th position of the phenol ring; R 1 is 4-(dimethylamino)phenyl, 4-(diphenylamino)phenyl, 4-(9-carbazolyl)phenyl; R 2 It is hydrogen, alkyl or aryl, and the connection point is any one of positions 3 to 6 of the phenol ring.

[0011] In addition, the present invention also proposes an application of the above-mentioned o-hydroxyphenylazole organic fluorescent molecule, which is used to detect the content of nerve agents or their simulants in solution and gas phase samples.

[0012] Furthermore, a specific method for detecting the content of nerve agents and their simulants in a solution sample is to dissolve an o-hydroxyphenylazole organic fluorescent molecule in an organic solvent as a test solution, and dissolve a solution sample nerve agent or its simulant in an organic solvent as a titration solution; the test solution is placed in a quartz cuvette, and then the titration solution is added to the quartz cuvette, and the fluorescence and ultraviolet-visible absorption spectra in the mixed solution are measured, and the content of the nerve agent or its simulant in the solution sample is obtained according to the spectra.

[0013] Furthermore, the concentration of the test solution was 1×10 -6 ~1×10 -3 mol / L.

[0014] Furthermore, the concentration of the titration solution is 1×10 -3 mol / L to pure product.

[0015] Furthermore, a specific method for detecting the content of nerve agents and their simulants in gas phase samples is to dissolve o-hydroxyphenylazole organic fluorescent molecules and polymer substrates in an organic solvent, spin-coat the resulting solution into a detection film, and then place it in air containing nerve agents or their simulants for a certain period of time, take out the detection film, measure and record fluorescence changes, and obtain the content of nerve agents or their simulants in the gas phase sample based on the fluorescence changes.

[0016] Furthermore, the polymer substrate is polymethyl methacrylate, polystyrene, polyethylene glycol, or polyvinyl alcohol; and the mass of the o-hydroxyphenylazole organic fluorescent molecules is 0.5% to 25% of the polymer substrate.

[0017] Furthermore, the rotation speed in the spin coating process is 1000-6000 rpm.

[0018] Further, the test film is placed in air containing a nerve agent or its simulant and maintained at the concentration for 30 seconds.

[0019] Furthermore, the organic solvent is halogenated alkane, ether, ketone, nitrile, benzene, alcohol, ester, amide.

[0020] (III) Beneficial effects

[0021] The present invention provides an o-hydroxyphenylazole organic fluorescent molecule and a detection method. By designing an o-hydroxyphenylazole molecule with an excited state intramolecular proton transfer (ESIPT) effect, a fluorescent probe with strong fluorescence and large Stokes shift can be obtained. When the recognition group phenolic hydroxyl group of the probe reacts with DCP, the ESIPT process is suppressed, and the fluorescence changes rapidly, so that DCP can be accurately identified. At the same time, due to the selective reactivity of the hydroxyl group, the interference of other acidic substances can be avoided to a large extent. The detection method of the present invention can quickly and sensitively realize the specific detection of nerve agents and their simulants in solution and gas phase. The implementation of the present invention is of great significance to the detection of nerve agents. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The structural formula of o-hydroxyphenylazole molecules (I) to (V);

[0023] Figure 2 is the fluorescence titration spectrum of molecule (II) to DCP;

[0024] Among them, curves a to j represent DCP concentrations of 0, 7.49×10 -6 mol / L、3.73×10 -5 mol / L、7.43×10 -5 mol / L、1.47×10 -4 mol / L、2.18×10 -4 mol / L、2.88×10 -4 mol / L、3.57×10 -4 mol / L、1.02×10 -3 mol / L、1.69×10 -3 mol / L, the abscissa is the fluorescence emission wavelength in nm, and the ordinate is the fluorescence intensity;

[0025] Figure 3 is the initial fluorescence intensity F0 of molecule (II) and the fluorescence intensity F after adding DCP t The ratio F0 / F tLinear fitting diagram of DCP concentration;

[0026] Where: The horizontal axis is the concentration of DCP, the unit is 10 -6 mol / L, the ordinate is the fluorescence intensity ratio F0 / F t ;

[0027] Figure 4 is the UV-visible absorption titration spectrum of molecule (IV)) to DCP;

[0028] Among them, curves a to j represent DCP concentrations of 0, 7.49×10 -6 mol / L、3.73×10 -5 mol / L、7.43×10 -5 mol / L、1.47×10 -4 mol / L、2.18×10 -4 mol / L、2.88×10 -4 mol / L、3.57×10 -4 mol / L、1.02×10 -3 mol / L、1.69×10 -3 mol / L, the abscissa is the absorption wavelength in nm, and the ordinate is the absorption intensity;

[0029] Figure 5 It is the fluorescence titration spectrum of molecule (IV) to DCP;

[0030] Among them, curves a to j represent DCP concentrations of 0, 7.49×10 -6 mol / L、3.73×10 -5 mol / L、7.43×10 -5 mol / L、1.47×10 -4 mol / L、2.18×10 -4 mol / L、2.88×10 -4 mol / L、3.57×10 -4 mol / L、1.02×10 -3 mol / L、1.69×10 -3 mol / L, the abscissa is the fluorescence emission wavelength in nm, and the ordinate is the fluorescence intensity;

[0031] Figure 6 is the UV-visible absorption peak intensity I of molecule (IV) t Linear fitting diagram of DCP concentration;

[0032] Figure 7is the fluorescence detection spectrum of molecule (II) to DCP in the gas phase;

[0033] Where: a ~ b curves represent DCP concentrations of 0 and 1 mg / m 3 The fluorescence emission curve at , the horizontal axis is the fluorescence emission wavelength, in nm, and the vertical axis is the fluorescence intensity;

[0034] Figure 8 is the fluorescence detection spectrum of molecule (IV) to DCP in the gas phase;

[0035] Where: a ~ b curves represent DCP concentrations of 0 and 1 mg / m 3 The fluorescence emission curve at , the horizontal axis is the fluorescence emission wavelength, in nm, and the vertical axis is the fluorescence intensity;

[0036] Fig. 9 is the fluorescence titration spectrum of molecule (II) p-toluenesulfonyl chloride (TsCl);

[0037] Among them, curves a to d represent TsCl concentrations of 0 and 7.49×10 -6 mol / L、3.73×10 -5 mol / L、7.43×10 -5 mol / L, the abscissa is the fluorescence emission wavelength in nm, and the ordinate is the fluorescence intensity;

[0038] Fig.10 It is the fluorescence titration spectrum of molecule (II) p-chloroacetyl chloride (AC);

[0039] Among them, curves a to e represent CAC concentrations of 0, 7.49×10 -6 mol / L、3.73×10 -5 mol / L、7.43×10 -5 mol / L、1.47×10 -4 mol / L, the abscissa is the fluorescence emission wavelength in nm, and the ordinate is the fluorescence intensity;

[0040] Fig.11 It is the fluorescence titration spectrum of molecule (II) acetyl chloride (AC);

[0041] Among them, curves a to e represent AC concentrations of 0, 7.49×10 -6 mol / L、3.73×10 -5 mol / L、7.43×10 -5 mol / L, the abscissa is the fluorescence emission wavelength in nm, and the ordinate is the fluorescence intensity;

[0042] Fig.12 is the fluorescence titration spectrum of molecule (II) against HCl;

[0043] Among them, curves a to d represent HCl concentrations of 0 and 7.49×10 -6 mol / L、3.73×10 -5 mol / L、7.43×10 -5 mol / L、1.47×10 -4 mol / L, the horizontal axis is the fluorescence emission wavelength, in nm, and the vertical axis is the fluorescence intensity. DETAILED DESCRIPTION

[0044] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples.

[0045] The o-hydroxyphenylazole organic fluorescent molecule designed by the present invention has the following general structural formula:

[0046]

[0047] The mother core structure is formed by connecting the 2nd position of phenol and the 2nd position of azole, X=O, S, NCH3; n=0-2; Ar is an aromatic ring or a heteroaromatic ring, and the connection point of Ar is the 4th or 5th position of the azole ring, or the 3rd to 6th position of the phenol ring; R 1 is 4-(dimethylamino)phenyl, 4-(diphenylamino)phenyl, 4-(9-carbazolyl)phenyl; R 2 It is hydrogen, alkyl or aryl, and the connection point is any one of positions 3 to 6 of the phenol ring.

[0048] The preparation route of the o-hydroxyphenylazole organic fluorescent molecules in the present invention refers to the following documents: B. Li, J. Lan, D. Wu, J. You, Angew. Chem., Int. Ed., 54 (2015) 14008-14012; K. Wang, R. Hu, J. Wang, J. Zhang, J. Liu, L. Zhou, L. Zhou, B. Li, ACS Mater. Lett. 4 (2022) 2337-2344. The synthesized compounds (I) to (V) are as follows: Figure 1 shown.

[0049] The principle of this type of o-hydroxyphenylazole organic fluorescent molecules being able to rapidly and sensitively achieve specific detection of nerve agents and simulants is that this type of molecule has the ESIPT effect. After the molecule transitions from the ground state to the excited state under the action of light, the proton-donating group (phenolic hydroxyl group) in the molecule undergoes intramolecular proton transfer with the adjacent proton-accepting group (N atom on the azole ring) through hydrogen bonding. During the transfer process, the photoexcited molecule releases the absorbed energy by transferring the acidic proton to the basic end of the molecule through keto-enol tautomerism. At the same time, the intramolecular conjugated structure undergoes a great change during the proton transfer process, and the spectrum undergoes a red shift, so that a very obvious Stokes shift can be observed. Therefore, with the phenolic hydroxyl group of this type of molecule as the recognition site, after a nucleophilic substitution reaction with the nerve agent, the proton of the phenolic hydroxyl group leaves in the form of hydrogen halide, thereby losing the ESIPT effect, resulting in changes in both the fluorescence wavelength and intensity.

[0050] Example 1 Detection method of DCP in solution sample by molecule (II)

[0051] Molecule (II) was dissolved in dichloromethane (DCM) as the test solution at a concentration of 5×10 -5 mol / L, DCP was dissolved in DCM as the titration solution with a concentration of 7.5×10 -3 mol / L. Take 1mL of the test solution and put it into a quartz cuvette; then, add 0-50μL of the titration solution and 1-3μL of pure DCP in sequence and measure the corresponding fluorescence spectrum. Figure 2 As shown in the figure, within 30 seconds after adding DCP, the maximum fluorescence emission peak of molecule (II) near 459nm was significantly weakened, accompanied by a red shift in wavelength; and under 365nm ultraviolet light, the solution quickly changed from bright blue-white fluorescence to dark blue fluorescence. Figure 3 As shown, the initial fluorescence intensity F0 of molecule (II) and the fluorescence intensity F after adding DCP t The ratio F0 / F t The concentration of DCP is between 0 and 7.4×10 -5 mol / L range, and the linear relationship is shown by linear fitting F0 / F t =0.377c+1.576, the unit value of c is 10 -6 mol / L, and the average standard deviation δ of the fluorescence spectrometer near the wavelength of 459nm was 0.0142, and the detection limit LOD was calculated to be 3δ / k = 1.13×10 -7 mol / L, the above shows that molecule (II) has a fast response time and high sensitivity to DCP.

[0052] Example 2 Detection method of DCP in solution sample by molecule (IV)

[0053] Molecule (IV) was dissolved in dichloromethane (DCM) as the test solution at a concentration of 5×10 -5 mol / L, DCP was dissolved in DCM as the titration solution with a concentration of 7.5×10 -3 mol / L. Take 1mL of the test solution and put it into a quartz cuvette; then, add 0-50μL of the titration solution and 1-3μL of pure DCP in sequence and measure the corresponding UV-visible absorption spectrum and fluorescence spectrum. Figure 4 As shown, within 30 seconds after the addition of DCP, the UV-visible absorption peaks of molecule (IV) near 314nm and 365nm were significantly weakened; Figure 5 As shown in the figure, the fluorescence emission peaks near 451nm and 514nm are significantly weakened, accompanied by a red shift in wavelength; and under 365nm ultraviolet light, the solution quickly changes from bright white fluorescence to dark blue-green fluorescence. Figure 6 As shown, the UV-visible absorption peak intensity of molecule (IV) is t The concentration of DCP is between 0 and 3.6×10 -4 mol / L range, and the linear relationship is shown by linear fitting I t =0.0028c+1.083, the unit value of c is 10 -6 mol / L, and the average standard deviation δ of the UV-visible absorption spectrometer near the wavelength of 314nm was 1.2×10 -4 , calculated detection limit LOD = 3δ / k = 1.29 × 10 -7 mol / L, the above shows that molecule (IV) has a fast response time and high sensitivity to DCP.

[0054] Example 3 Detection method of DCP in gas phase sample by molecule (II)

[0055] The molecule (II) and polymethyl methacrylate (PMMA) were dissolved in DCM at a mass ratio of 1:49, and then spin-coated on a quartz substrate at a speed of 2000 rpm to prepare a fluorescence detection film. The detection film was then placed in air containing DCP at a DCP concentration of 1 mg / m 3 Keep it at this concentration for 30 seconds, take out the test film, measure and record the fluorescence change. Figure 7 As shown, the test film is at a concentration of 1 mg / m 3Within 30 seconds after the DCP was detected, the maximum fluorescence emission peak near 476nm was significantly weakened and almost completely quenched to the same level as the baseline; and under 365nm ultraviolet light, the fluorescence color of the film changed from green-blue (CIE1931: 0.13, 0.28) to blue-white (CIE1931: 0.22, 0.26). The above shows that the fluorescence detection film made of molecule (II) and PMMA has a fast response time and very high sensitivity to DCP in gas phase samples, and can be visually identified.

[0056] Example 4 Detection Method of DCP in Gas Phase Sample by Molecule (IV)

[0057] The molecule (IV) and PMMA were dissolved in DCM at a mass ratio of 1:49, and then spin-coated on a quartz substrate at a speed of 2000 rpm to prepare a fluorescence detection film. The detection film was then placed in air containing DCP at a DCP concentration of 1 mg / m 3 Keep it at this concentration for 30 seconds, take out the test film, measure and record the fluorescence change. Figure 8 As shown, the test film is at a concentration of 1 mg / m 3 Within 30 seconds after the DCP was detected, the maximum fluorescence emission peaks near 440nm and 515nm were significantly weakened and almost completely quenched; and under 365nm ultraviolet light, the fluorescence color of the film changed from blue (CIE1931: 0.17, 0.17) to blue-green (CIE1931: 0.17, 0.20). The above shows that the fluorescence detection film made of molecule (IV) and PMMA has a fast response time and high sensitivity to DCP in gas phase samples, and can achieve visual identification.

[0058] Example 5 Selectivity experiment of molecule (II) for DCP

[0059] The solute DCP in the titration solution in Example 1 was replaced by acidic interfering substances such as TsCl, CAC, AC and HCl, respectively, and the other titration and detection experimental conditions remained unchanged, and the corresponding UV-visible absorption and fluorescence spectra were obtained respectively. Figures 9 to 12 As shown, within 30 seconds after the addition of the above-mentioned acidic interfering substances, the maximum fluorescence emission peak of molecule (II) near 459 nm hardly changed or was slightly weakened, which shows that molecule (II) has good selectivity for the detection of DCP.

[0060] The present invention utilizes phenolic hydroxyl groups to undergo nucleophilic substitution reactions with nerve agents and their simulants to inhibit the ESIPT effect, which can quickly achieve fluorescence changes with large Stokes shifts, and can avoid background fluorescence interference through fluorescence ratios, thereby achieving highly sensitive detection; in addition, using phenolic hydroxyl groups as recognition groups can also improve the specificity of detection, especially for the interference of common acidic substances (hydrochloric acid, acetic acid, toluenesulfonyl chloride, chloroacetyl chloride, acetyl chloride, etc.), which can avoid universal problems in the field of nerve agent detection. The fluorescence detection method provided by the present invention has the characteristics of fast response speed, good sensitivity and specificity, and the changes in fluorescence signals in both liquid and gas phases are very obvious, and can even be identified by naked eyes, so that the method is expected to provide a fast and highly sensitive nerve agent on-site detection solution in the fields of public safety and national defense.

[0061] 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 technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An o-hydroxyphenylazole organic fluorescent molecule, characterized in that: The general structural formula of the o-hydroxyphenylazole organic fluorescent molecule is as follows: The mother core structure is formed by connecting the 2nd position of phenol and the 2nd position of azole, X=O, S, NCH3; n=0-2; Ar is an aromatic ring or a heteroaromatic ring, and the connection point of Ar is the 4th or 5th position of the azole ring, or the 3rd to 6th position of the phenol ring; R 1 is 4-(dimethylamino)phenyl, 4-(diphenylamino)phenyl, 4-(9-carbazolyl)phenyl; R 2 It is hydrogen, alkyl or aryl, and the connection point is any one of positions 3 to 6 of the phenol ring.

2. An application of the o-hydroxyphenylazole organic fluorescent molecule as claimed in claim 1, characterized in that: The o-hydroxyphenylazole organic fluorescent molecule is used to detect the content of nerve agents or their simulants in solution and gas phase samples.

3. The use of the o-hydroxyphenylazole organic fluorescent molecule according to claim 2, characterized in that: The specific method for detecting the content of nerve agents and their simulants in a solution sample is to dissolve an o-hydroxyphenylazole organic fluorescent molecule in an organic solvent as a test solution, and dissolve a solution sample nerve agent or its simulant in an organic solvent as a titration solution; The test solution is placed in a quartz cuvette, and then the titration solution is added to the quartz cuvette. The fluorescence and UV-visible absorption spectra in the mixed solution are measured, and the content of the nerve agent or its simulant in the solution sample is obtained according to the spectra.

4. The use of the o-hydroxyphenylazole organic fluorescent molecule according to claim 3, characterized in that: The concentration of the test solution is 1×10 -6 ~1×10 -3 mol / L.

5. The use of the o-hydroxyphenylazole organic fluorescent molecule according to claim 3, characterized in that: The concentration of the titration solution is 1×10 -3 mol / L to pure product.

6. The use of the o-hydroxyphenylazole organic fluorescent molecule according to claim 2, characterized in that: The specific method for detecting the content of nerve agents and their simulants in gas phase samples is to dissolve o-hydroxyphenylazole organic fluorescent molecules and polymer substrates in an organic solvent, spin-coat the resulting solution into a detection film, and then place it in air containing nerve agents or their simulants for a certain period of time, take out the detection film, measure and record the fluorescence changes, and obtain the content of nerve agents or their simulants in the gas phase sample based on the fluorescence changes.

7. The use of the o-hydroxyphenylazole organic fluorescent molecule according to claim 6, characterized in that: The polymer substrate is polymethyl methacrylate, polystyrene, polyethylene glycol and polyvinyl alcohol; the mass of the o-hydroxyphenylazole organic fluorescent molecules is 0.5% to 25% of the polymer substrate.

8. The use of the o-hydroxyphenylazole organic fluorescent molecule according to claim 6, characterized in that: The rotation speed in the spin coating process is 1000 to 6000 rpm.

9. The use of the o-hydroxyphenylazole organic fluorescent molecule according to claim 6, characterized in that: The test film is placed in air containing a nerve agent or its simulant and maintained at that concentration for 30 seconds.

10. The use of the o-hydroxyphenylazole organic fluorescent molecule according to claim 3 or 6, characterized in that: The organic solvent is halogenated alkane, ether, ketone, nitrile, benzene, alcohol, ester, amide.

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