Fluorescent probe for hydrogen sulfide detection and preparation method and application thereof

Abstract

The invention relates to a fluorescent probe for hydrogen sulfide detection and a preparation method and application thereof, the chemical name of the fluorescent probe for hydrogen sulfide detection is 2-((E)-2-(3-(dicyanomethylene)-5, 5-dimethylcyclohexene-1-ene-1-yl) vinyl)-4-((E)-2-(quinoline-2-yl) vinyl) phenyl-2, 4-dinitrobenzene sulfonic acid, and the structural formula of the fluorescent probe is shown in the description. The structural formula is shown as a formula I in the specification. The fluorescent probe for hydrogen sulfide detection is prepared by taking 2-methylquinoline, 4-hydroxyisophthalaldehyde, dicyanoisophorone and 2, 4-dinitrobenzenesulfonyl chloride as raw materials, and carrying out condensation reaction and nucleophilic substitution. Compared with the prior art, the fluorescent probe for hydrogen sulfide detection has the advantages of simple synthesis method, simple and easily available raw materials, good selectivity to hydrogen sulfide, high sensitivity and large Stokes shift, and has a good application prospect in hydrogen sulfide detection.

Description

Technical Field

[0001] The present invention relates to the technical field of fluorescent probes, and in particular to a fluorescent probe for hydrogen sulfide detection, its preparation method and application. Background Art

[0002] Hydrogen sulfide participates in the sulfur cycle in the natural environment and is crucial for the balance of the ecosystem. At the same time, as an endogenous gas signaling molecule in the human body, it regulates various physiological processes. However, hydrogen sulfide is a highly toxic gas that causes serious harm to the environment and human health. Low-concentration exposure can lead to symptoms such as eye irritation and headache, while high-concentration exposure may be rapidly fatal, and it is corrosive and can damage production equipment. Therefore, designing and synthesizing a tool that can recognize hydrogen sulfide is of great significance. It can not only meet the needs of environmental monitoring, biomedical research, industrial safety, etc., but also provide more efficient and accurate technical support for research and applications in related fields.

[0003] There are various detection methods for hydrogen sulfide. Common ones include titrimetric analysis, electrochemistry, ion chromatography, biosensing, etc. However, these traditional methods often have many limitations. For example, titrimetric analysis is complex in operation, requiring precise measurement and complex chemical reaction steps; although electrochemistry has a relatively fast response, it has high requirements for instrument equipment and is easily interfered by environmental factors; ion chromatography has high sensitivity and selectivity, but the equipment is expensive and the operation is complex, not suitable for on-site rapid detection; biosensing has problems such as poor stability and long response time. As a new detection technology, fluorescent probes have received extensive attention due to their unique advantages. A fluorescent probe is a molecule that can specifically interact with the target analyte and cause changes in fluorescence signals. In the detection of hydrogen sulfide, fluorescent probes can provide real-time and sensitive detection, and are not interfered by environmental light, suitable for on-site rapid detection of complex samples. The fluorescent probe method has the advantages of high sensitivity, fast response, simple operation, and real-time monitoring. For example, after some fluorescent probes react with hydrogen sulfide, the fluorescence intensity will change significantly, or the fluorescence wavelength will shift, and these changes can be quickly detected by instruments such as fluorescence spectrometers. The high sensitivity of fluorescent probes enables them to detect extremely low concentrations of hydrogen sulfide, which is of great significance for early warning and environmental monitoring. Its fast response ability can achieve real-time monitoring and timely detect the leakage or change of hydrogen sulfide. In addition, the simplicity of the operation of fluorescent probes also makes them more advantageous in practical applications, without complex pretreatment steps, suitable for on-site rapid detection. Designing and synthesizing probes that can selectively recognize and detect HS- ions has broad application prospects. The application of fluorescent probe technology in the detection of hydrogen sulfide can not only overcome the limitations of traditional methods, but also provide a more efficient, sensitive and convenient detection means. This not only plays an important role in protecting human life and health, but also provides strong technical support for environmental protection and industrial safety.

[0004] Quinoline fluorophores have been widely used in fields such as drug synthesis and optical materials due to their semi-rigid molecular structures, nitrogen-containing heterocycles, and good water solubility. However, quinoline fluorophores have some limitations. For example, their conjugated planes are relatively small and their excitation wavelengths are short, resulting in poor recognition performance for analytes when used as fluorescent probes and being difficult to be directly applied to real life. To overcome these drawbacks, the present invention designed a quinoline-based fluorescent probe through molecular modification. Summary of the Invention

[0005] The purpose of the present invention is to provide a fluorescent probe for hydrogen sulfide detection, its preparation method and application to overcome the above-mentioned defects of quinoline fluorophores.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] One of the technical solutions of the present invention is to provide a fluorescent probe for hydrogen sulfide detection, whose chemical name is 2-((E)-2-(3-(dicyanomethylene)-5,5-dimethylcyclohex-1-en-1-yl)vinyl)-4-((E)-2-(quinolin-2-yl)vinyl)phenyl-2,4-dinitrobenzenesulfonic acid, and its structural formula is shown in the following formula Ⅰ:

[0008]

[0009] Another technical solution of the present invention is to provide a preparation method of the fluorescent probe for hydrogen sulfide detection as described in the above technical solution, including the following steps:

[0010] S1. Synthesis of (E)-2-hydroxy-5-(2-(quinolin-2-yl)vinyl)benzaldehyde:

[0011] Mix 4-hydroxyisophthalaldehyde and 2-methylquinoline, and perform a high-temperature reaction to precipitate a yellow solid. Recrystallize the yellow solid with absolute ethanol to obtain (E)-2-hydroxy-5-(2-(quinolin-2-yl)vinyl)benzaldehyde as a pale yellow solid;

[0012] S2. Synthesis of 2-(3-((E)-2-hydroxy-5-((E)-2-(quinolin-2-yl)vinyl)styryl)-5,5-dimethylcyclohex-2-en-1-ylidene)propanedinitrile:

[0013] In an inert atmosphere, dissolve the (E)-2-hydroxy-5-(2-(quinolin-2-yl)vinyl)benzaldehyde obtained in step S1 in acetonitrile, then add dicyanoisophorone and piperidine and perform a high-temperature reaction to precipitate a red solid. Recrystallize the red solid with absolute ethanol to obtain 2-(3-((E)-2-hydroxy-5-((E)-2-(quinolin-2-yl)vinyl)styryl)-5,5-dimethylcyclohex-2-en-1-ylidene)propanedinitrile as a red solid;

[0014] S3. Synthesis of the probe 2-((E)-2-(3-(dicyanomethylene)-5,5-dimethylcyclohex-1-en-1-yl)vinyl)-4-((E)-2-(quinolin-2-yl)vinyl)phenyl-2,4-dinitrobenzenesulfonic acid:

[0015] In an inert atmosphere, dissolve 2-(3-((E)-2-hydroxy-5-((E)-2-(quinolin-2-yl)vinyl)styryl)-5,5-dimethylcyclohexene-2-en-1-ylidene)malononitrile obtained in step S2 in anhydrous dichloromethane, add triethylamine and 2,4-dinitrobenzenesulfonyl chloride, react at room temperature, extract with ethyl acetate, and purify the organic layer by silica gel column chromatography to obtain the yellow solid probe 2-((E)-2-(3-(dicyanomethylene)-5,5-dimethylcyclohexene-1-en-1-yl)vinyl)-4-((E)-2-(quinolin-2-yl)vinyl)phenyl 2,4-dinitrobenzenesulfonate.

[0016] In some specific embodiments, in step S1, the molar ratio of 4-hydroxyisophthalaldehyde to 2-methylquinoline is 1:(1.5 - 2.0).

[0017] In some specific embodiments, in step S1, the temperature of the high-temperature reaction is 120 - 150 °C, and the time of the high-temperature reaction is 16 - 24 h. After the reaction is completed, recrystallize by refluxing in absolute ethanol for 1 - 3 h.

[0018] In some specific embodiments, in step S2, the molar ratio of (E)-2-hydroxy-5-(2-(quinolin-2-yl)vinyl)benzaldehyde, dicyanoisophorone, and piperidine is (3 - 4):(5 - 6):(0.1 - 0.6).

[0019] More preferably, the molar ratio of (E)-2-hydroxy-5-(2-(quinolin-2-yl)vinyl)benzaldehyde, dicyanoisophorone, and piperidine is 3.6:5.4:0.14.

[0020] In some specific embodiments, in step S2, the temperature of the high-temperature reaction is 80 °C, and the time of the high-temperature reaction is 24 - 36 h. After the reaction is completed, recrystallize by refluxing in absolute ethanol for 1 - 3 h.

[0021] In some specific embodiments, in step S3, the feeding ratio of 2-(3-((E)-2-hydroxy-5-((E)-2-(quinolin-2-yl)vinyl)styryl)-5,5-dimethylcyclohexene-2-en-1-ylidene)malononitrile, triethylamine, 2,4-dinitrobenzenesulfonyl chloride, and dichloromethane is (1 - 2) mmol:(3 - 4) mmol:(2 - 3) mmol:(9 - 11) mL.

[0022] More preferably, the feeding ratio of 2-(3-((E)-2-hydroxy-5-((E)-2-(quinolin-2-yl)vinyl)styryl)-5,5-dimethylcyclohex-2-en-1-ylidene)malononitrile, triethylamine, 2,4-dinitrobenzenesulfonyl chloride, and dichloromethane is 1.125 mmol: 3.38 mmol: 2.82 mmol: 10 mL.

[0023] In some specific embodiments, in step S3, the reaction time at room temperature is 20 - 30 h.

[0024] In some specific embodiments, in step S3, the mobile phase used for column chromatography purification is a mixed solution of petroleum ether and dichloromethane with a volume ratio of 6:1.

[0025] In some specific embodiments, in steps S2 and S3, the inert atmosphere is nitrogen.

[0026] The fluorescence probe for hydrogen sulfide detection of the present invention is obtained from 2-methylquinoline, 4-hydroxyisophthalaldehyde, dicyanoisophorone, and 2,4-dinitrobenzenesulfonyl chloride through condensation reaction and nucleophilic substitution. The reaction process is as follows:

[0027]

[0028] In the formula, 1 is 2-methylquinoline, 2 is (E)-2-hydroxy-5-(2-(quinolin-2-yl)vinyl)benzaldehyde, and 3 is 2-(3-((E)-2-hydroxy-5-((E)-2-(quinolin-2-yl)vinyl)styryl)-5,5-dimethylcyclohex-2-en-1-ylidene)malononitrile.

[0029] The third technical solution of the present invention is to provide a test paper for hydrogen sulfide detection, which includes filter paper and a dimethyl sulfoxide solution containing the fluorescence probe adsorbed on the filter paper, and the fluorescence probe is the fluorescence probe for hydrogen sulfide detection described in one of the above technical solutions.

[0030] The fourth technical solution of the present invention is to provide an application of the fluorescence probe for hydrogen sulfide detection described in one of the above technical solutions, and the hydrogen sulfide is detected after the fluorescence probe for hydrogen sulfide detection is dissolved in an aqueous solution of dimethyl sulfoxide.

[0031] In some specific embodiments, when detected by ultraviolet absorption spectrometry, the fluorescence probe for hydrogen sulfide detection is dissolved in a mixed solution of dimethyl sulfoxide and water with a volume ratio of 7:3 for testing hydrogen sulfide.

[0032] In some specific embodiments, when detected by a fluorescence spectrophotometer, the fluorescence probe for hydrogen sulfide detection is dissolved in a mixed solution of dimethyl sulfoxide and water with a volume ratio of 7:3 for testing hydrogen sulfide.

[0033] The fluorescent probe for hydrogen sulfide detection of the present invention uses 2-methylquinoline as the fluorophore and 2,4-dinitrobenzenesulfonic acid as the recognition site. A benzene ring and dicyanoisophorone are introduced between the fluorophore and the recognition site, which can effectively increase the conjugated plane of the probe molecule, thereby increasing the ultraviolet absorption wavelength. This structural optimization not only improves the photophysical properties of the probe, but also makes it show higher sensitivity and selectivity when detecting analytes.

[0034] Under the condition that dimethyl sulfoxide and water (V / V = 7:3) are used as solvents, in the ultraviolet spectrum, this fluorescent probe has an ultraviolet absorption peak at 395 nm. After adding HS - , the ultraviolet absorption peak at 395 nm will red-shift to 440 nm, and a new ultraviolet absorption peak will appear at 612 nm; when viewed under a fluorescent lamp, it is observed that the probe solution turns from colorless to green after adding HS - . When other anions are added, there are no obvious changes in the ultraviolet absorption spectrum and the solution color of this fluorescent probe. In the fluorescence spectrum, with 620 nm as the excitation wavelength, this fluorescent probe has no fluorescence emission peak. After adding HS - , a fluorescence emission peak appears at 740 nm. Under the irradiation of a 365-nm ultraviolet lamp, it is observed that the probe solution fluoresces brightly after adding HS - , changing from non-fluorescent to orange fluorescence, while other anions have no change.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The synthesis method of the fluorescent probe for hydrogen sulfide detection provided by the present invention is simple, the raw materials are simple and easy to obtain, it has good selectivity and relatively high sensitivity to hydrogen sulfide, and has a large Stokes shift (120 nm), and has good application prospects in the detection of hydrogen sulfide. Description of the Drawings

[0037] Figure 1 A is the fluorescence emission spectrum diagram of the fluorescent probe (20 μmol·L -1 ) of the present invention for detecting different concentrations of HS - (0 - 200 μmol·L -1 ) added in DMSO / H2O solution;

[0038] Figure 1 B is the intensity diagram of the fluorescence emission peak at 740 nm of the fluorescent probe (20 μmol·L -1 ) of the present invention for detecting the gradual increase of HS - concentration in DMSO / H2O solution;

[0039] Figure 2To detect the ultraviolet absorption spectra of the fluorescent probe of the present invention (20 μmol·L -1 ) when different anions (200 μmol·L -1 ) and HS - (200 μmol·L -1 ) are added to the DMSO / H2O solution;

[0040] Figure 3 To detect the fluorescence emission spectra of the fluorescent probe of the present invention (20 μmol·L -1 ) when different anions (200 μmol·L -1 ) and HS - (200 μmol·L -1 ) are added to the DMSO / H2O solution;

[0041] Figure 4 To obtain the bar graph of the ultraviolet absorption intensity of the response of the fluorescent probe of the present invention (20 μmol·L -1 ) to HS - (200 μmol·L -1 ) in the DMSO / H2O solution in the coexistence of other anions (200 μmol·L -1 ). Each column represents F - , Cl - , Br - , I - , NO3 - , ClO4 - , H2PO4 - , OH - , AcO - , SCN - , CN - , BF4 - , S2 - , HSO4 - , HSO3 - , S2O3 2- , dithiothreitol, glycine, leucine, glutathione;

[0042] Figure 5 To obtain the bar graph of the fluorescence emission intensity of the response of the fluorescent probe of the present invention (20 μmol·L -1 ) to HS - (200 μmol·L -1 ) in the DMSO / H2O solution in the coexistence of other anions (200 μmol·L -1 ). Each column represents F - , Cl - , Br - , I - , NO3- , ClO4 - , H2PO4 - , OH - , AcO - , SCN - , CN - , BF4 - , S2 - , HSO4 - , HSO3 - , S2O3 2- , dithiothreitol, glycine, leucine, glutathione;

[0043] Figure 6 Calculation chart of the ultraviolet detection limit of the fluorescent probe of the present invention in DMSO / H2O solution;

[0044] Figure 7 Calculation chart of the fluorescence detection limit of the fluorescent probe of the present invention in DMSO / H2O solution;

[0045] Figure 8 For the fluorescent probe test paper of the present invention, different concentrations of HS are added dropwise - Picture under irradiation with a hand-held ultraviolet lamp at 365 nm. Specific embodiments

[0046] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and the detailed implementation manners and specific operation processes are given, but the protection scope of the present invention is not limited to the following embodiments.

[0047] The names, specifications and manufacturer information of the raw materials used in each embodiment of the present invention are shown in Table 1:

[0048] Table 1

[0049] Raw material name Specification Manufacturer information 2-Methylquinoline 100g Shanghai Titan Scientific Co., Ltd. 4-Hydroxyisophthalaldehyde 100g Shanghai Titan Scientific Co., Ltd. Dicyanoisophorone 100g Shanghai Titan Scientific Co., Ltd. Dimethyl sulfoxide 1000 mL Shanghai Titan Scientific Co., Ltd. 2,4-Dinitrobenzenesulfonyl chloride 5g Shanghai Titan Scientific Co., Ltd. Triethylamine 1000 mL Shanghai Titan Scientific Co., Ltd.

[0050] The model of the silica gel column used in each embodiment of the present invention is: 45 cm in length, 45 mm in diameter, and the manufacturer is: Beijing Lianhua Glass Instrument Co., Ltd.

[0051] Example 1

[0052] This example provides a preparation method of a fluorescent probe DCIQ-DNBS for hydrogen sulfide detection, including the following steps:

[0053] (1) Synthesis of (E)-2-hydroxy-5-(2-(quinolin-2-yl)vinyl)benzaldehyde:

[0054] In a 50 mL single-necked round-bottom flask, 4-hydroxyisophthalaldehyde (1 g, 6.66 mmol) was added, and 2-methylquinoline (1.43 g, 9.99 mmol) was slowly added. The temperature was raised to 120 °C and stirred, and the reaction progress was monitored by TLC. After 16 h, when the reaction was completed and yellow solid appeared, heating was stopped, and the reaction solution was cooled to room temperature. The reaction solution was washed with absolute ethanol, filtered by suction with a Buchner funnel, and finally the solid compound was recrystallized twice with absolute ethanol to obtain a pale yellow solid (1.6 g, 87.25%);

[0055] The above-obtained yellow powdery solid product was measured by a nuclear magnetic resonance instrument (Bruker AVANCE III 400 MHz), and the data are shown as follows:

[0056] 1H NMR (400 MHz, DMSO-d6) δ [ppm]: 11.27 (s, 1H), 9.89 (s, 1H), 8.35 - 8.30 (m, 2H), 8.08 (d, J = 16.5 Hz, 1H), 8.01 (d, J = 8.0 Hz, 1H), 7.94 (d, J = 7.5 Hz, 1H), 7.83 (d, J = 8.6 Hz, 1H), 7.78 - 7.72 (m, 2H), 7.62 (d, J = 16.4 Hz, 1H), 7.55 (t, J = 7.3 Hz, 1H), 7.12 (d, J = 8.4 Hz, 1H); 13 C NMR (125 MHz, DMSO-d6) δ [ppm]: 192.40, 161.72, 156.15, 148.17, 137.73, 136.44, 131.85, 130.67, 129.84, 129.41, 129.26, 127.65, 125.97, 124.11, 121.40, 120.12, 117.69, 116.40, 40.45.

[0057] Through the nuclear magnetic resonance spectrum data analysis of the above-obtained yellow powdery solid product, the results show that the above-obtained yellow powdery solid product is (E)-2-hydroxy-5-(2-(quinolin-2-yl)vinyl)benzaldehyde.

[0058] (2) Synthesis of 2-(3-((E)-2-hydroxy-5-((E)-2-(quinolin-2-yl)vinyl)styryl)-5,5-dimethylcyclohex-2-en-1-ylidene)propanedinitrile (DCIQ):

[0059] In a 50 mL three-necked flask, (E)-2-hydroxy-5-(2-(quinolin-2-yl)vinyl)benzaldehyde (1.00 g, 3.6 mmol) was dissolved in 20 mL of acetonitrile, then dicyanoisophorone (1.00 g, 5.4 mmol) and a catalytic equivalent of piperidine (0.05 g, 0.14 mmol) were added; under nitrogen protection, the reaction mixture was reacted at 80 °C for 24 h. After the reaction was completed, it was cooled to room temperature, and a red solid precipitated out. It was filtered and washed with absolute ethanol; finally, the solid compound was recrystallized with absolute ethanol to obtain a red solid (1.3 g, 80.7%).

[0060] The above-obtained red solid product was measured by a nuclear magnetic resonance instrument (Bruker AVANCE III 400 MHz), and the data are shown as follows:

[0061] 1 H NMR (400 MHz, DMSO-d6) δ [ppm]: 8.4 (d, J = 8.5 Hz, 1H), 8.15 (s, 1H), 8.05 - 7.99 (m, 2H), 7.95 (d, J = 6.5 Hz, 1H), 7.8 (d, J = 9 Hz, 1H), 7.7 - 7.4 (m, 1H), 7.62 - 7.52 (m, 3H), 7.33 (dd, J = 36.5 Hz, J = 16 Hz, 2H), 6.96 (d, J = 8.5 Hz, 1H), 6.858 (s, 1H), 2.616 (s, 2H), 2.561 (s, 2H), 1.031 (s, 6H); 13 C NMR (125 MHz, DMSO-d6) δ [ppm]: 170.80, 158.01, 157.15, 156.44, 148.21, 138.59, 137.02, 130.79, 130.32, 129.37, 129.13, 128.30, 128.09, 127.48, 127.44, 127.35, 126.57, 124.14, 122.08, 120.51, 117.00, 114.61, 113.83, 75.50, 32.16, 27.96.

[0062] Through the nuclear magnetic resonance spectrum data analysis of the above-obtained red solid product, the results show that the above-obtained red solid product is 2-(3-((E)-2-hydroxy-5-((E)-2-(quinolin-2-yl)vinyl)styryl)-5,5-dimethylcyclohex-2-en-1-ylidene)propanedinitrile (DCIQ).

[0063] (3) Synthesis of the probe 2-((E)-2-(3-(dicyanomethylene)-5,5-dimethylcyclohex-1-en-1-yl)vinyl)-4-((E)-2-(quinolin-2-yl)vinyl)phenyl 2,4-dinitrobenzenesulfonate:

[0064] In a 50 mL round-bottom flask, under a nitrogen atmosphere, at room temperature, DCIQ (0.5 g, 1.25 mmol) was dissolved in 10 mL of DCM (anhydrous dichloromethane). Triethylamine (0.34 g, 3.38 mmol) was added, and the mixture was stirred for 30 minutes. Then, 2,4-dinitrobenzenesulfonyl chloride (0.75 g, 2.82 mmol) was slowly added, and the mixture was stirred overnight at room temperature. The reaction was monitored by TLC. After the raw materials were completely reacted, the reaction solution was concentrated by rotary evaporation, then extracted with CH2Cl2 (20 mL × 3), and the organic layer was washed with saturated brine, dried over anhydrous Na2SO4, filtered, and concentrated under vacuum. Further purification was carried out by column chromatography with the mobile phase of petroleum ether:dichloromethane = 6:1 (v:v), to obtain a pale yellow solid (0.63 g, yield 83.0%).

[0065] The pale yellow solid product obtained above was measured by a nuclear magnetic resonance instrument (Bruker AVANCE III 400 MHz), and the data are shown as follows:

[0066] 1 H NMR (400 MHz, DMSO-d6) δ [ppm]: 8.54 (d, J = 2.0 Hz, 1H), 8.38 - 8.31 (m, 2H), 8.28 (s, 1H), 8.14 (d, J = 8.7 Hz, 1H), 7.95 (d, J = 8.1 Hz, 1H), 7.87 (d, J = 8.4 Hz, 1H), 7.82 - 7.72 (m, 2H), 7.63 - 7.58 (m, 2H), 7.55 (dd, J = 11.6, 5.5 Hz, 2H), 7.43 (d, J = 8.5 Hz, 1H), 7.34 (s, 1H), 7.30 (s, 1H), 6.93 (s, 1H), 2.62 (s, 2H), 2.54 (s, 2H), 1.02 (s, 6H); 1313C NMR(125 MHz, DMSO-d6) δ [ppm]: 170.66, 155.66, 151.19, 148.34, 147.88, 147.13, 137.48, 136.91, 134.03, 132.65, 131.85, 130.73, 130.13, 129.02, 128.37, 127.73, 127.16, 126.58, 125.04, 124.06, 121.17, 120.53, 114.15, 113.41, 77.74, 42.72, 32.14, 27.91. HRMS-ESI (m / z): [M+H]+ Calcd. for (C 36 H 27 N5O7S): 674.1724; Found: 674.1724.

[0067] Based on the nuclear magnetic resonance spectrum data analysis of the obtained pale yellow solid product, the results show that the obtained red solid product is the probe 2-((E)-2-(3-(dicyanomethylene)-5,5-dimethylcyclohex-1-en-1-yl)vinyl)-4-((E)-2-(quinolin-2-yl)vinyl)phenyl-2,4-dinitrobenzenesulfonic acid (DCIQ-DNBS).

[0068] The anion recognition performance test of the prepared DCIQ-DNBS above was carried out as follows:

[0069] (1) Titration experiment of the fluorescent probe for hydrogen sulfide

[0070] The required solutions and their preparations are as follows:

[0071] a. Dissolve the fluorescent probe DCIQ-DNBS in DMSO to prepare a 5000 μmol·L -1 probe stock solution.

[0072] b. Prepare an HS - stock solution in water with a concentration of 50000 μmol·L -1 .

[0073] c. Measure 100 μL of the 5000 μmol·L -1 probe stock solution and dissolve it in a 25 mL volumetric flask, and dilute it to 25 mL with the solution DMSO / H2O (7:3, pH = 7.4, v / v) to prepare a 25 mL 20 μM probe solution.

[0074] Titration experiment: Pour 25 mL of the 20 μM probe solution into a 100 mL wide-mouth conical flask, and add 2 μL of the 50000 μmol·L -1 HS- The stock solution was shaken evenly, and its ultraviolet absorption spectrum and fluorescence emission spectrum were measured. This operation was repeated, and the ultraviolet and fluorescence titration spectrograms of the probe DCIQ-DNBS were collected.

[0075] The results showed that, as Figure 1 shown in A, when there was no HS - in the system, the probe had no fluorescence emission peak. As the concentration of HS - ions continuously increased (0 - 200 μmol·L -1 ), the fluorescence emission peak of the probe DCIQ-2DNP at 740 nm gradually increased. As Figure 1 shown in B, when the added HS - reached saturation (200 μmol·L -1 ), the fluorescence emission peak at 740 nm no longer changed, indicating that the reaction between the probe DCIQ-DNBS and H2S reached a saturation state.

[0076] (2) Selectivity study of the fluorescence probe for hydrogen sulfide

[0077] The required solutions and their preparations were as follows:

[0078] a. The fluorescence probe DCIQ-DNBS was dissolved in DMSO to prepare a 5000 μmol·L -1 probe stock solution.

[0079] b. Various anions (F - , C1 - , Br - , I - , NO3 - , ClO4 - , H2PO4 - , OH - , AcO - , SCN - , CN - , BF4 - , S2 - , HSO4 - , HSO3 - , S2O3 2- ) and biothiols (dithiothreitol, glycine, leucine, glutathione) were dissolved in HPLC-grade DMSO solution to prepare 20 different anion analyte solutions of 10 mL 50000 μmol·L -1 for standby.

[0080] c. An HS - stock solution was prepared in a water buffer at a concentration of 50000 μmol·L -1 .

[0081] Take 20 10-mL test tubes, transfer 5 mL of DMSO / H2O (7:3, pH = 7.4, v / v) into the test tubes, and respectively measure 20 μL of 5000 μmol·L -1 probe stock solution into the test tubes (the concentration of the probe is 20 μM). During the test, use a micropipette to add 200 μmol·L -1 of different anion analyte solutions with saturated equivalent to the test tubes for testing, collect the corresponding ultraviolet and fluorescence spectra, and continue to add 200 μmol·L -1 of HS - stock solution to the test tubes, and collect the ultraviolet and fluorescence spectra.

[0082] The results show that under the condition of DMSO / H2O mixed solvent, the probe itself has an ultraviolet absorption peak at 395 nm. Only the addition of HS - will cause the ultraviolet absorption peak at 395 nm to redshift to 440 nm, and a new ultraviolet absorption peak appears at 612 nm. At the same time, the probe solution changes from colorless to green ( Figure 2 ). Meanwhile, in the fluorescence spectrum, with 620 nm as the excitation wavelength, only after the addition of HS - , a fluorescence emission peak appears at 740 nm, and the Stokes shift is 120 nm. Under the irradiation of a 365-nm ultraviolet lamp, it is observed that the probe solution fluoresces brightly after the addition of HS - , changing from non-fluorescent to orange fluorescence ( Figure 3 ). However, when adding other ions (F - , C1 - , Br - , I - , NO3 - , ClO4 - , H2PO4 - , OH - , AcO - , SCN - , CN - , BF4 - , S2 - , HSO4 - , HSO3 - , S2O3 2- ) and biothiols (dithiothreitol, glycine, leucine, glutathione), the ultraviolet and fluorescence spectra and the solution color of the probe DCIQ-DNBS do not change, as Figures 2-3 shown. This indicates that the probe DCIQ-DNBS has a high selectivity for HS - in the mixed solvent DMSO / H2O (7:3, pH = 7.4, v / v).

[0083] (3) Anti-interference ability detection

[0084] The required solutions and their preparations are as follows:

[0085] a. Dissolve the fluorescent probe DCIQ-DNBS in DMSO to prepare a probe stock solution with a concentration of 5000 μmol·L -1 .

[0086] b. Dissolve various anions (F - , Cl - , Br - , I - , NO3 - , ClO4 - , H2PO4 - , OH - , AcO - , SCN - , CN - , BF4 - , S2 - , HSO4 - , HSO3 - , S2O3 2- ) and biothiols (dithiothreitol, glycine, leucine, glutathione) in an HPLC-grade DMSO solution to dissolve and prepare 20 different anion analyte solutions with a volume of 10 mL and a concentration of 50000 μmol·L -1 for standby.

[0087] c. Prepare an HS - stock solution in water with a concentration of 50000 μmol·L -1 .

[0088] Take 20 10-mL test tubes, transfer 5 mL of DMSO / H2O (7:3, pH = 7.4, v / v) to the test tubes, and use a micropipette to measure 20 μL of the 5000 μmol·L -1 probe stock solution into the test tubes (the concentration of the probe is 20 μM). During the test, add 200 μmol·L -1 of different anions (F - , Cl - , Br - , I - , NO3 - , ClO4 - , H2PO4 - , OH - , AcO - , SCN - , CN - , BF4 - , S2 -,HSO4 - ,HSO3 - ,S2O3 2- ) and biothiols (dithiothreitol, glycine, leucine, glutathione) were shaken well, and ultraviolet and fluorescence emission spectra were detected. Finally, 200 μmol·L of saturated equivalent hydrogen sulfide was added to each test tube, shaken well, and its fluorescence emission spectrum was detected again. -1 The results showed that in the presence of other anions, HS

[0089] could still significantly increase the ultraviolet absorption at 612 nm and the fluorescence emission intensity at 740 nm of the fluorescent probe DCIQ-DNBS ( - ), so the fluorescent probe DCIQ-DNBS had good anti-interference ability for the detection of HS Figures 4-5 ), and other anions would not cause any interference to the detection results. - (4) Determination of the lowest detection limit of the fluorescent probe DCIQ-DNBS for hydrogen sulfide

[0090] There was a good linear relationship between the ultraviolet absorbance at 612 nm and the concentration of HS

[0091] (R2 could reach 0.99678). By the formula LOD = 3*δ / S (where σ is the standard deviation of multiple blank measurements and S is the sensitivity of the method (i.e., the slope of the standard curve)), the detection limit of the fluorescent probe DCIQ-DNBS for hydrogen sulfide was calculated to be 9.0 μM ( - ), which indicated that the probe DCIQ-DNBS had good sensitivity to hydrogen sulfide in a DMSO solution with a water content of 30%. Figure 6 The fluorescence intensity of the probe DCIQ-DNBS had a good linear relationship with the concentration of HS

[0092] within a certain range (R2 could reach 0.99766). By the formula LOD = 3*δ / S (where σ is the standard deviation of multiple blank measurements and S is the sensitivity of the method (i.e., the slope of the standard curve)), the fluorescence detection limit of the probe DCIQ-DNBS for hydrogen sulfide was calculated to be 49 nM ( - ). This indicated that the probe DCIQ-DNBS had good sensitivity to HS Figure 7 in a DMSO solution with a water content of 30%. - Example 2

[0093] Based on the probe DCIQ-DNBS prepared in Example 1, this example provides a test paper for detecting hydrogen sulfide, and its preparation method includes the following steps:

[0094]

[0095] Cut the filter paper into strips with a length of 2 cm and a width of 1 cm, soak them in a DMSO solution of 1 mM probe DCIQ-DNBS overnight, take them out and air dry naturally to obtain the test paper for detecting hydrogen sulfide.

[0096] Perform the following performance tests on the prepared test paper for detecting hydrogen sulfide:

[0097] Drop DMSO solutions containing 0.2 mM, 0.5 mM, 1 mM, and 5 mM HS - onto the above test paper. After air drying, observe the change in its fluorescence color under a 365 nm ultraviolet lamp.

[0098] Experiments show that under the irradiation of a 365 nm ultraviolet lamp, the test paper shows no fluorescence in the absence of HS - . When HS - is added, it can be seen that the fluorescence gradually increases, showing a bright orange fluorescence ( Figure 8 ), indicating that the probe DCIQ-DNBS can detect hydrogen sulfide in the form of a test paper.

[0099] The above description of the embodiments is to enable those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A fluorescent probe for hydrogen sulfide detection, characterized in that, Its chemical name is 2-((E)-2-(3-(dicyanomethylene)-5,5-dimethylcyclohexene-1-en-1-yl)vinyl)-4-((E)-2-(quinolin-2-yl)vinyl)phenyl-2,4-dinitrobenzenesulfonic acid, and its structural formula is shown in the following formula Ⅰ:

2. A preparation method of the fluorescence probe for hydrogen sulfide detection as described in claim 1, characterized in that, It includes the following steps: S1. Synthesis of (E)-2-hydroxy-5-(2-(quinolin-2-yl)vinyl)benzaldehyde: Mix 4-hydroxyisophthalaldehyde and 2-methylquinoline, and carry out a high-temperature reaction to precipitate a yellow solid. Recrystallize the yellow solid with absolute ethanol to obtain (E)-2-hydroxy-5-(2-(quinolin-2-yl)vinyl)benzaldehyde as a pale yellow solid; S2. Synthesis of 2-(3-((E)-2-hydroxy-5-((E)-2-(quinolin-2-yl)vinyl)styryl)-5,5-dimethylcyclohexene-2-en-1-ylmethylene)malononitrile: In an inert atmosphere, dissolve the (E)-2-hydroxy-5-(2-(quinolin-2-yl)vinyl)benzaldehyde obtained in step S1 in acetonitrile, then add dicyanoisophorone and piperidine and mix. Carry out a high-temperature reaction to precipitate a red solid. Recrystallize the red solid with absolute ethanol to obtain 2-(3-((E)-2-hydroxy-5-((E)-2-(quinolin-2-yl)vinyl)styryl)-5,5-dimethylcyclohexene-2-en-1-ylmethylene)malononitrile as a red solid; S3. Synthesis of the probe 2-((E)-2-(3-(dicyanomethylene)-5,5-dimethylcyclohexene-1-en-1-yl)vinyl)-4-((E)-2-(quinolin-2-yl)vinyl)phenyl-2,4-dinitrobenzenesulfonic acid: In an inert atmosphere, dissolve the 2-(3-((E)-2-hydroxy-5-((E)-2-(quinolin-2-yl)vinyl)styryl)-5,5-dimethylcyclohexene-2-en-1-ylmethylene)malononitrile obtained in step S2 in anhydrous dichloromethane, add triethylamine and 2,4-dinitrobenzenesulfonyl chloride and mix. Carry out a reaction at room temperature, extract with ethyl acetate, and purify the organic layer by silica gel column chromatography to obtain the yellow solid probe 2-((E)-2-(3-(dicyanomethylene)-5,5-dimethylcyclohexene-1-en-1-yl)vinyl)-4-((E)-2-(quinolin-2-yl)vinyl)phenyl-2,4-dinitrobenzenesulfonic acid.

3. The preparation method of the fluorescence probe for hydrogen sulfide detection according to claim 2, characterized in that, In step S1, the molar ratio of 4-hydroxyisophthalaldehyde to 2-methylquinoline in the feed is 1:(1.5 - 2.0).

4. The preparation method of the fluorescence probe for hydrogen sulfide detection according to claim 2, characterized in that, In step S1, the temperature of the high-temperature reaction is 120 - 150 °C, and the time of the high-temperature reaction is 16 - 24 h.

5. The preparation method of the fluorescence probe for hydrogen sulfide detection according to claim 2, wherein In step S2, the molar ratio of (E)-2-hydroxy-5-(2-(quinolin-2-yl)vinyl)benzaldehyde, dicyanoisophorone and piperidine in the feed is (3 - 4):(5 - 6):(0.1 - 0.6).

6. The preparation method of the fluorescence probe for hydrogen sulfide detection according to claim 2, characterized in that, In step S2, the temperature of the high-temperature reaction is 80 °C, and the time of the high-temperature reaction is 24 - 36 h.

7. The preparation method of the fluorescence probe for hydrogen sulfide detection according to claim 2, characterized in that, In step S3, the feeding ratio of 2-(3-((E)-2-hydroxy-5-((E)-2-(quinolin-2-yl)vinyl)styryl)-5,5-dimethylcyclohex-2-en-1-ylidene)malononitrile, triethylamine, 2,4-dinitrobenzenesulfonyl chloride, and dichloromethane is (1-2) mmol : (3-4) mmol : (2-3) mmol : (9-11) mL.

8. The preparation method of the fluorescence probe for hydrogen sulfide detection according to claim 2, wherein, In step S3, the reaction time at room temperature is 20-30 h, and the mobile phase used for column chromatography purification is a mixed solution of petroleum ether and dichloromethane with a volume ratio of 6:

1.

9. A test strip for detecting hydrogen sulfide, characterized in that, It includes a filter paper and a dimethyl sulfoxide solution containing a fluorescent probe adsorbed on the filter paper, and the fluorescent probe is the fluorescent probe for hydrogen sulfide detection described in claim 1.

10. Use of a fluorescence probe for hydrogen sulfide detection as described in claim 1, characterized in that, The fluorescent probe for hydrogen sulfide detection is dissolved in a dimethyl sulfoxide aqueous solution and then used to detect hydrogen sulfide.

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