A fluorescent material for detecting hydrogen sulfide and a preparation method and application thereof

Abstract

The application discloses a fluorescent material for hydrogen sulfide detection and a preparation method and application thereof, and relates to the field of fluorescent materials.The fluorescent material is constructed by bridging dicyanoisophorone (DCI) and N-alkylated benzimidazole through divinylphenol to form a D-pi-A system, and 2,4-dinitrophenyl ether (DNP) is introduced on the electron-deficient quaternary carbon on the phenolic hydroxyl group and the DCI unit at the same time.Compared with the prior art, the application adopts a two-site cascade sulfurolysis strategy, reacts rapidly with H2S, and has good selectivity and strong anti-interference ability.In addition, the fluorescent material of the application has realized visual detection of H2S in a spoiled food sample through a prepared test paper, and has good application potential.

Description

Technical Field

[0001] This invention relates to the field of fluorescent materials, specifically to a fluorescent material for hydrogen sulfide detection, its preparation method, and its application. Background Technology

[0002] Hydrogen sulfide (H2S) is a gas with a typical rotten egg odor and plays an indispensable regulatory role in various physiological and pathological processes. Physiologically, hydrogen sulfide participates in key life activities such as neural regulation, maintenance of redox homeostasis, anti-inflammatory responses, and metabolic regulation; however, abnormal fluctuations in its concentration (increases or decreases) can trigger significant physiological disorders and are closely related to the pathogenesis of various diseases such as hypertension, diabetes, and cirrhosis. Furthermore, hydrogen sulfide is one of the main volatile sulfur compounds released during the spoilage of high-protein foods, posing a potential threat to human health. Therefore, accurate and real-time detection of hydrogen sulfide is not only crucial for ensuring the quality of daily life but also provides a feasible approach for the early diagnosis of related diseases.

[0003] Various methods exist for detecting hydrogen sulfide, including titration analysis, electrochemical methods, ion chromatography, and biosensing. However, these traditional methods often suffer from limitations such as complex operation, high cost, long response time, or inability to achieve real-time monitoring. Fluorescent materials, as a novel detection technology, have attracted widespread attention due to their unique advantages such as high sensitivity, rapid response, ease of operation, and the ability to achieve rapid real-time monitoring. They can detect target analytes by generating changes in fluorescence signals through specific reactions. For example, some fluorescent materials exhibit significant changes in fluorescence intensity or wavelength shifts after reacting with hydrogen sulfide, which can be rapidly detected using instruments such as fluorescence spectrometers. Furthermore, the high sensitivity of fluorescent materials allows for the detection of extremely low concentrations of hydrogen sulfide, which is crucial for early warning and environmental monitoring. Their rapid response capability enables real-time monitoring, allowing for timely detection of hydrogen sulfide leaks or changes. In addition, the ease of operation of fluorescent materials makes them more advantageous in practical applications, requiring no complex pretreatment steps and suitable for rapid on-site detection. Therefore, the synthesis of materials capable of specifically identifying HS is crucial. - Fluorescent materials containing ions have broad application prospects. Furthermore, the application of fluorescent material technology in hydrogen sulfide detection not only overcomes the limitations of traditional methods but also provides a more efficient, sensitive, and convenient detection approach. This plays a vital role in safeguarding human life and health, and also provides strong technical support for environmental protection and industrial safety.

[0004] Numerous fluorescent materials capable of identifying hydrogen sulfide have been reported, most of which are designed and invented based on a single-site response strategy. However, this single-site response strategy generally suffers from insufficient reaction efficiency, resulting in slow response or insufficient sensitivity and selectivity to meet ideal detection requirements. To overcome these limitations, this invention designs and synthesizes a novel fluorescent material using a two-site cascade thiolysis strategy. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing hydrogen sulfide fluorescent detection materials in terms of detection sensitivity, selectivity, response efficiency, and stability in practical applications, by providing a fluorescent material for hydrogen sulfide detection, its preparation method, and its application. The fluorescent material can generate an effective fluorescent response to hydrogen sulfide, and the identification and detection of hydrogen sulfide can be achieved by observing the change in fluorescence signal before and after the interaction with hydrogen sulfide. Simultaneously, it considers both the feasibility of material preparation and the performance of detection applications, thereby expanding its application in the field of rapid hydrogen sulfide detection.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: One of the technical solutions of the present invention is to provide a fluorescent material for hydrogen sulfide detection, the chemical name of which is 2-(5-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-(2,6-dinitrophenoxy)styryl)-3,3-dimethylcyclohex-1,5-dien-1-yl)-2-(2,6-dinitrophenyl)malonadionitrile, and its structural formula is shown in Formula I below: Formula I.

[0007] The second technical solution of the present invention is to provide a method for preparing a fluorescent material for hydrogen sulfide detection as described in one of the above technical solutions, comprising the following steps: Synthesis of S1, (E)-5-(2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxybenzaldehyde: N-Butyl-2-methylbenzimidazole was mixed with 4-hydroxyisophthalaldehyde and reacted at high temperature to give a yellow solid precipitate. The solid was filtered and the filter cake was washed with anhydrous ethanol to give a pale yellow solid (E)-5-(2-(1-Butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxybenzaldehyde. Synthesis of S2,2-(3-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxystyryl)-5,5-dimethylcyclohex-2-en-1-yl)malonadionitrile: In an inert atmosphere, (E)-5-(2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxybenzaldehyde obtained in step S1 was dissolved in acetonitrile, and then dicyanoisophorone and piperidine were added and mixed. The mixture was reacted at high temperature to obtain a red solid precipitation. The red solid was recrystallized with anhydrous ethanol to obtain a red solid 2-(3-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxystyryl)-5,5-dimethylcyclohex-2-ene-1-yl)malonitrile; S3. Synthesis of the fluorescent material 2-(5-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-(2,6-dinitrophenoxy)styryl)-3,3-dimethylcyclohexyl-1,5-dien-1-yl)-2-(2,6-dinitrophenyl)malonadionitrile: In an inert atmosphere, 2-(3-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxystyryl)-5,5-dimethylcyclohex-2-en-1-yl)malononitrile obtained in step S2 was dissolved in N,N-dimethylformamide, and potassium carbonate and 2,4-dinitrofluorobenzene were added and mixed. The mixture was reacted at room temperature, extracted with dichloromethane, and the organic layer was purified by silica gel column chromatography to obtain a yellow solid 2-(5-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-(2,6-dinitrophenoxy)styryl)-3,3-dimethylcyclohex-1,5-dien-1-yl)-2-(2,6-dinitrophenyl)malononitrile.

[0008] In some specific embodiments, in step S1, the molar ratio of N-butyl-2-methylbenzimidazole to 4-hydroxyisophthalaldehyde is 1:(1.1-1.3).

[0009] In some specific embodiments, in step S1, the temperature of the high-temperature reaction is 120°C and the reaction time is 12-18 hours.

[0010] In some specific embodiments, in step S2, the molar ratio of (E)-5-(2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxybenzaldehyde, dicyanoisophorone and piperidine is (3-4) mmol: (5-6) mmol: (0.1-0.5) mmol.

[0011] In some specific embodiments, in step S2, the high-temperature reaction temperature is 80°C, and the high-temperature reaction time is 24-36 hours. After the reaction is completed, recrystallization is carried out by reflux in anhydrous ethanol for 1-3 hours.

[0012] In some specific embodiments, in step S3, the molar ratio of 2-(3-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxystyryl)-5,5-dimethylcyclohex-2-ene-1-yl)malononitrile, potassium carbonate, 2,4-dinitrofluorobenzene, and N,N-dimethylformamide is (1-2) mmol:(3-5) mmol:(3-5) mmol:(9-11) mL.

[0013] As a more preferred embodiment, the molar ratio of 2-(3-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxystyryl)-5,5-dimethylcyclohex-2-en-1-yl)malononitrile, potassium carbonate, 2,4-dinitrofluorobenzene, and N,N-dimethylformamide is 1.025 mmol: 3.58 mmol: 3.58 mmol: 10 mL.

[0014] In some specific embodiments, the reaction time at room temperature in step S3 is 16-24 hours.

[0015] In some specific embodiments, in step S3, the mobile phase used for column chromatography purification is a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 6:1.

[0016] In some specific embodiments, in steps S2 and S3, the inert atmosphere is nitrogen.

[0017] The fluorescent material for hydrogen sulfide detection of the present invention is obtained from N-butyl-2-methylbenzimidazole, 4-hydroxy-isophthalaldehyde, dicyanoisophorone, and 2,4-dinitrofluorobenzene via condensation reaction and nucleophilic substitution. The reaction process is as follows:

[0018] In the formula, 1 is N-butyl-2-methylbenzimidazole, 2 is 4-hydroxyisophthalaldehyde, 3 is (E)-5-(2-(1-butyl-1H-benzimidazole-2-yl)vinyl)-2-hydroxybenzaldehyde, 4 is dicyanoisophorone, and 5 is 2-(3-((E)-5-((E)-2-(1-butyl-1H-benzimidazole-2-yl)vinyl)-2-hydroxystyryl) -5,5-Dimethylcyclohexyl-2-en-1-yl)malononitrile, 6 is 2,4-dinitrofluorobenzene, and 7 is 2-(5-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-(2,6-dinitrophenoxy)styryl)-3,3-dimethylcyclohexyl-1,5-dien-1-yl)-2-(2,6-dinitrophenyl)malononitrile.

[0019] The third technical solution of the present invention is to provide an application of a fluorescent material for hydrogen sulfide detection as described in one of the above technical solutions, wherein the fluorescent material for hydrogen sulfide detection is dissolved in a dimethyl sulfoxide aqueous solution to detect hydrogen sulfide.

[0020] The fourth technical solution of the present invention is to provide a test strip for hydrogen sulfide detection, comprising filter paper and a dimethyl sulfoxide solution containing fluorescent material adsorbed on the filter paper, wherein the fluorescent material is the fluorescent material for hydrogen sulfide detection described in one of the above technical solutions.

[0021] The fifth technical solution of the present invention is to provide a hydrogen sulfide test strip for use in spoiled food, wherein the hydrogen sulfide test strip detects hydrogen sulfide released from spoiled food.

[0022] In some specific embodiments, when using ultraviolet absorption spectroscopy for detection, the fluorescent material for hydrogen sulfide detection is dissolved in a mixed solution of dimethyl sulfoxide and PBS in a volume ratio of 9:1 to test for hydrogen sulfide.

[0023] In some specific embodiments, when using a fluorescence spectrophotometer for detection, the fluorescent material for hydrogen sulfide detection is dissolved in a mixed solution of dimethyl sulfoxide and PBS in a volume ratio of 9:1 to test for hydrogen sulfide.

[0024] The fluorescent material for hydrogen sulfide detection of the present invention is constructed by linking divinylphenol with dicyanoisophorone (DCI) and N-alkylated benzimidazole to form a D-π-A system, which can effectively increase the conjugated surface of the fluorescent material molecule, thereby increasing the ultraviolet absorption wavelength. At the same time, 2,4-dinitrophenyl ether (DNP) is introduced on the electron-deficient quaternary carbon of the phenolic hydroxyl group and the DCI unit to construct a two-site responsive fluorescent material. This structural optimization not only improves the photophysical properties of the fluorescent material, but also makes it exhibit higher sensitivity and selectivity when detecting analytes.

[0025] Under conditions where dimethyl sulfoxide and PBS (v / v=9:1) are used as solvents, the fluorescent material exhibits a UV absorption peak at 340 nm in the UV spectrum. The addition of HS... - Subsequently, the absorption peak at 340 nm redshifted, and new absorption peaks appeared at 445 nm and 675 nm; under natural light, it was observed that the addition of HS... - The solution changed from colorless to yellow-green; however, the addition of other relevant analytes did not significantly alter the UV absorption spectrum of the fluorescent material or the solution color. In the fluorescence spectrum, using 480 nm as the excitation wavelength, the fluorescent material showed no obvious fluorescence emission peak. The addition of HS... - Subsequently, dual fluorescence emission peaks appeared at 610 nm and 745 nm. Under 365 nm UV illumination, the addition of HS was observed... -The fluorescence of the solution turned on after the addition of other relevant analytes, changing from no fluorescence to orange fluorescence.

[0026] Compared with the prior art, the present invention has the following advantages: (1) The fluorescent material provided by the present invention has a relatively obvious fluorescence response to hydrogen sulfide. The presence of hydrogen sulfide can cause a significant change in the fluorescence signal, which is beneficial to improving the response sensitivity and response efficiency of hydrogen sulfide detection, and making it easier to identify low concentrations of hydrogen sulfide.

[0027] (2) The fluorescent material provided by the present invention has good recognition selectivity for hydrogen sulfide, which can reduce the interference of other coexisting substances on the fluorescence detection process, improve the identification and reliability of the detection results, and is beneficial to the selective detection of hydrogen sulfide in complex systems.

[0028] (3) The fluorescent material of the present invention takes into account detection performance, stability and ease of preparation. Its fluorescence response stability and practical detection applicability are improved. The preparation process is easy to implement, which is conducive to expanding the application scope of the material in environmental detection, biological detection and other hydrogen sulfide detection scenarios. Attached Figure Description

[0029] Figure 1 To achieve the fluorescent material (20 μmol·L⁻¹) of the present invention -1 The detection was performed by adding different concentrations of HS to DMSO / PBS solution. - The following is a UV-Vis absorption spectrum.

[0030] Figure 2 To achieve the fluorescent material (20 μmol·L⁻¹) of the present invention -1 The detection was performed by adding different concentrations of HS to DMSO / PBS solution. - The fluorescence emission spectrum is shown below.

[0031] Figure 3 To achieve the fluorescent material (20 μmol·L⁻¹) of the present invention -1 ) Detection of absorbance at 670 nm in DMSO / PBS solution and HS - Linear relationship of concentration (150-300μM).

[0032] Figure 4 To achieve the fluorescent material (20 μmol·L⁻¹) of the present invention -1 ) Detection of fluorescence intensity at 745 nm in DMSO / PBS solution and lg[HS] - The linear relationship between them.

[0033] Figure 5 To achieve the fluorescent material (20 μmol·L⁻¹) of the present invention -1) Detection of HbA1c activity in DMSO / PBS solution when coexisting with other common analytes - The response UV absorption intensity histogram, with each column representing HS. - F - Cl - ,Br - I - NO3 - ClO4 - H2PO4 - OH - AcO - SCN - CN - BF4 - S 2- HSO4 - HSO3 - S2O3 2- , 2-ME, DTT, GSH.

[0034] Figure 6 To achieve the fluorescent material (20 μmol·L⁻¹) of the present invention -1 ) Detection of HbA1c activity in DMSO / PBS solution when coexisting with other common analytes - The response fluorescence emission intensity histogram, with each column representing HS. - F - Cl - ,Br - I - NO3 - ClO4 - H2PO4 - OH - AcO - SCN - CN - BF4 - S 2- HSO4 - HSO3 - S2O3 2- , 2-ME, DTT, GSH.

[0035] Figure 7 Different concentrations of HS were added to the fluorescent material test strip of the present invention. - Images taken under 365nm ultraviolet light and in natural light.

[0036] Figure 8 The images show fluorescence monitoring of hydrogen sulfide released by the fluorescent material test strip of the present invention on fresh chicken and pork (left) and rotten chicken and pork (right). Detailed Implementation

[0037] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] The names, specifications, and manufacturer information of the raw materials used in the various embodiments of this invention are shown in Table 1: Table 1

[0039] The silicone column used in the various embodiments of the present invention is 45cm long and 45mm in diameter, and is manufactured by Beijing Lianhua Glass Instrument Co., Ltd.

[0040] Example 1

[0041] This embodiment provides a method for preparing the fluorescent material N-Bu-DCIB-2DNP for hydrogen sulfide detection, comprising the following steps: (1) Synthesis of (E)-5-(2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxybenzaldehyde: In a 50 mL round-bottom flask, N-butyl-2-methylbenzimidazole (0.50 g, 2.66 mmol) and 4-hydroxy-isophthalaldehyde (0.48 g, 3.19 mmol) were added and mixed, and the mixture was stirred at 120 °C for 12 hours. After the starting material disappeared (monitored by TLC), a yellow solid precipitated in the reaction solution. After cooling to room temperature, the mixture was filtered and the filter cake was washed with anhydrous ethanol to give a pale yellow solid (0.95 g, yield 81%).

[0042] The pale yellow solid obtained above was measured using a nuclear magnetic resonance (NMR) instrument, and the data are shown below: 1 HNMR (400MHz, DMSO-d6)δ [ppm]: 11.33(s,1H),9.89(s,1H),8.37(d,J=2.20Hz,1H),8.14(d,J=16.00Hz,1H),7.76(d,J=2.00Hz,1H),7.74(d,J=2.10Hz,1H),7.36(d,J=1 6.0Hz,1H),7.59(m,2H),7.20(m,2H),7.10(d,J=8.30Hz,1H),4.42(t,J=7.00Hz,2H),1.72(m,2H),1.28(m,2H),0.88(t,J=7.20Hz,3H).

[0043] 13 CNMR (100MHz, DMSO-d6)δ [ppm]: 191.59,161.81,151.35,143.37,135.59,131.59,130.96,129.21,123.87,122.54,122.50,119.08,117.02,115.45,110.77,42.80,32.67,19.96,14.12.

[0044] Analysis of the nuclear magnetic resonance spectroscopy data of the pale yellow solid obtained above showed that the pale yellow solid obtained above is (E)-5-(2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxybenzaldehyde.

[0045] (2) Synthesis of 2-(3-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxystyryl)-5,5-dimethylcyclohex-2-en-1-yl)malonadionitrile (N-Bu-DCIB): In a 50 mL three-necked flask, a mixture of (E)-5-(2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxybenzaldehyde (0.5 g, 1.56 mmol) and dicyanoisophorone (0.44 g, 2.34 mmol) was dissolved in anhydrous acetonitrile (15 mL), followed by the addition of a catalytic equivalent of piperidine (0.02 g, 0.15 mmol). Under nitrogen protection, the reaction mixture was stirred at 80 °C for 24 hours, and the reaction progress was monitored by TLC until the starting material was completely consumed. After cooling to room temperature, a red solid precipitated, which was filtered and washed with anhydrous ethanol. Finally, the solid was recrystallized from anhydrous ethanol for 2 hours to give a red solid N-Bu-DCIB (0.65 g, 80% yield).

[0046] The red solid obtained above was measured using a nuclear magnetic resonance instrument (Bruker Avance III 400MHz), and the data are shown below: 1 HNMR (400MHz, DMSO-d6)δ [ppm]: 10.71(s,1H),8.14(d,J=16.0Hz,1H),8.12(s,2H),7.87(d,J=16.0Hz,1H),7.57(m,5H),7.29(s,2H),7.21(s,2H),6.83 (s,1H),4.43(t,J=7.0Hz,2H),2.62(s,2H),2.56(s,1H),1.73(m,2H),1.28(m,2H),1.03(s,6H),0.89(t,J=7.5Hz,3H).

[0047] 13 CNMR (100MHz, DMSO-d6)δ [ppm]: 170.74,158.17,156.90,151.56,143.37,138.43,135.88,131.44,130.35,128.37,128.01,127.45,123.74,122.49,122.41,122.14,118.99,117.09,114.68,114.56,113.79,110.71,75.65,42.80,38.74,32.59,32.17,27.93,19.93,14.10.

[0048] HRMS-ESI(m / z):[M+H] + Calculated for C 32 H 33 N4O + ,489.2654;Found:489.2654.

[0049] Analysis of the nuclear magnetic resonance spectroscopy data of the red solid obtained above showed that the red solid obtained above is 2-(3-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxystyryl)-5,5-dimethylcyclohex-2-ene-1-yl)malononitrile.

[0050] (3) Synthesis of the fluorescent material 2-(5-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-(2,6-dinitrophenoxy)styryl)-3,3-dimethylcyclohexyl-1,5-dien-1-yl)-2-(2,6-dinitrophenyl)malonadionitrile (N-Bu-DCIB-2DNP): In a 50 mL three-necked flask, N-Bu-DCIB (1.00 g, 2.05 mmol) was dissolved in 20 mL of LDM, and K₂CO₃ (0.99 g, 7.16 mmol) was added. The mixture was stirred for 30 min, and then 2,4-dinitrofluorobenzene (1.33 g, 7.16 mmol) was slowly added. The mixture was stirred at room temperature for 16 h. The reaction was monitored by TLC. Once the reactants had reacted completely, the reaction mixture was poured into water (200 mL), and then extracted with CH₂Cl₂ (100 mL × 3). The organic layer was washed with saturated brine, dried over anhydrous Na₂SO₄, filtered, and concentrated under vacuum. Further purification was performed by column chromatography (PE:EA = 6:1) to obtain a yellow solid N-Bu-DCIB-2DNP (0.85 g, yield 50.5%).

[0051] The yellow solid obtained above was measured using a nuclear magnetic resonance instrument (Bruker Avance III 400MHz), and the data are shown below: 1 HNMR (400MHZ, DMSO-d6) [ppm]: 8.93(d,J=5.92Hz,2H),8.77(d,J=6.16Hz,1H),8.44(d,J=6.28Hz,2H),8.29( s,1H),8.21(d,J=8.72Hz,1H),7.90(d,J=15.88Hz,1H),7.64(m,2H),7.55(m, 2H),7.20(m,2H),6.97(d,J=16.20Hz,1H),6.11(s,1H),6.01(s,1H),4.39(t, J=7.28Hz,2H),1.64(m,2H),1.20(m,2H),1.15(s,6H),0.80(t,J=7.28Hz,3H).

[0052] 13 CNMR (100MHz, DMSO-d6) [ppm]: 155.19,151.51,150.51,149.60,148.71,143.19,142.24,140.39,139.84,135.94,135.86,133.42,130.42,129.59,129.41,128.91,128.70,125.68,122.80,122.66,121.78,120.00,119.30,112.83,111.00,44.33,42.97,33.50,32.77,27.42,19.96,14.10.

[0053] HRMS-ESI(m / z):[M+H] + Calculated for C 44 H 377 N8O9 + ,821.2678;Found,821.2680.

[0054] Analysis of the nuclear magnetic resonance (NMR) spectroscopy data of the yellow solid obtained above showed that the yellow solid was a fluorescent material 2-(5-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-(2,6-dinitrophenoxy)styryl)-3,3-dimethylcyclohex-1,5-dien-1-yl)-2-(2,6-dinitrophenyl)malononitrile.

[0055] The recognition performance of the fluorescent material N-Bu-DCIB-2DNP prepared above was tested: (1) Titration experiment of fluorescent materials The required solution and its preparation are as follows: a. Dissolve the fluorescent material N-Bu-DCIB-2DNP in DMSO to prepare a solution of 5000 μmol·L⁻¹ -1 The reserve liquid.

[0056] b. Prepare HS in water - The stock solution has a concentration of 50,000 μmol·L⁻¹.

[0057] c. Measure 100 μL of 5000 μmol·L⁻¹ -1 The stock solution was dissolved in a 25 mL volumetric flask and diluted to 25 mL with DMSO / PBS (9:1, pH=7.4, v / v) to prepare a 25 mL 20 μM fluorescent material solution.

[0058] Titration experiment: Pour 25 mL of 20 μM fluorescent material solution into a 100 mL wide-mouth conical flask, adding 2 μL of 50000 μmol·L⁻¹ solution dropwise each time. -1 HS - After shaking the stock solution until it is homogeneous, its ultraviolet absorption spectrum and fluorescence emission spectrum are measured. This operation is repeated to collect the ultraviolet and fluorescence titration spectra of the fluorescent material N-Bu-DCIB-2DNP.

[0059] The results show that, Figure 1 The system shown does not contain HS. - At that time, the fluorescent material itself has an absorption peak at 340 nm, and with HS - The addition of [a substance] caused the absorption peaks to red shift to 445 nm and 675 nm, accompanied by a change in solution color from colorless to yellow-green. Additionally, in the fluorescence titration spectrum ([…]), […] Figure 2 In this process, the fluorescent material itself does not fluoresce; however, the addition of HS... - Subsequently, orange fluorescence was activated, and dual fluorescence emission peaks appeared at 610 nm and 745 nm.

[0060] (2) Determination of the lowest detection limit of the fluorescent material N-Bu-DCIB-2DNP for hydrogen sulfide The UV absorbance at 670 nm showed a good linear relationship with the concentration of HS (R² reached 0.9816). The UV detection limit of the fluorescent material N-Bu-DCIB-2DNP for detecting hydrogen sulfide was calculated to be 22.12 μM using 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)). Figure 3 This indicates that N-Bu-DCIB-2DNP has good sensitivity to hydrogen sulfide.

[0061] Furthermore, the fluorescence intensity of the fluorescent material N-Bu-DCIB-2DNP also exhibits a good linear relationship with the concentration of HS within a certain range (R² reaches 0.9985). Using 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 fluorescent material N-Bu-DCIB-2DNP for detecting hydrogen sulfide is calculated to be 51.48 nM. Figure 4 This further demonstrates that N-Bu-DCIB-2DNP has good sensitivity to hydrogen sulfide.

[0062] (3) Selectivity study and anti-interference ability test of fluorescent materials The required solution and its preparation are as follows: a. Dissolve the fluorescent material N-Bu-DCIB-2DNP in DMSO to prepare a solution of 5000 μmol·L⁻¹ -1 The reserve liquid.

[0063] b. Various common analytes (F - Cl - ,Br - I - NO3 - ,ClO 4- H2PO 4- OH - AcO - SCN - CN - BF 4- S 2- HSO 4- HSO3 - S2O3 2-(2-ME, DTT, GSH) were dissolved in HPLC-grade DMSO solution to prepare 10 mL of 50000 μmol·L⁻¹ analyte solution for later use.

[0064] c. Prepare HS in water - Stock solution, concentration 50000 μmol·L -1 .

[0065] Take 20 10 mL test tubes and transfer 5 mL of DMSO / PBS (9:1, pH=7.4, v / v) into each tube. Then, pipette 20 μL of 5000 μmol·L⁻¹ fluorescent material stock solution (concentration 20 μM) into each tube. During testing, add a saturated equivalent (60 eq) of a different analyte (HS-Hydrogen-5 ... - F - Cl - ,Br - I - NO3 - ,ClO 4- H2PO 4- OH - AcO - SCN - CN - BF 4- S 2- HSO 4- HSO3 - S2O3 2- (2-ME, DTT, GSH) were thoroughly shaken, and ultraviolet and fluorescence spectra were detected. Finally, saturated equivalents of hydrogen sulfide were added to each test tube, shaken well, and the ultraviolet and fluorescence spectra were detected again.

[0066] The results showed that the addition of other analytes did not significantly alter the UV and fluorescence spectra of the fluorescent material or the color of the solution; only the addition of HS caused a significant change. - Subsequently, its ultraviolet spectrum changed significantly, accompanied by a noticeable change in solution color, and orange fluorescence was activated. Furthermore, when coexisting with other relevant analytes, HS... - It can still cause significant changes in the ultraviolet absorption and fluorescence emission intensity of fluorescent materials. Figure 5-6 Therefore, the fluorescent material N-Bu-DCIB-2DNP is effective against HS. - The detection has good selectivity and strong anti-interference ability.

[0067] Example 2

[0068] Based on the fluorescent material N-Bu-DCIB-2DNP prepared in Example 1, this example provides a test strip for detecting hydrogen sulfide, the preparation method of which includes the following steps: Cut filter paper into strips 2cm long and 1cm wide, soak them in a 1mM N-Bu-DCIB-2DNP DMSO solution, remove them overnight, and let them air dry to obtain hydrogen sulfide test paper.

[0069] The prepared hydrogen sulfide test paper was subjected to the following performance tests: Add 0.5 mM, 1 mM, 2 mM, and 5 mM HS solutions respectively to the above test strips. - After the solution is air-dried, observe its fluorescence changes and the color changes of the test paper under 365nm ultraviolet light and natural light.

[0070] The results showed that under 365nm ultraviolet light irradiation, the test strip was effective in the absence of HS. - When HS is added, it exhibits no fluorescence; when HS is added... - Afterwards, the orange fluorescence gradually intensifies. Figure 7 This indicates that the fluorescent material N-Bu-DCIB-2DNP can be used as a portable test strip for rapid detection of hydrogen sulfide.

[0071] Example 3

[0072] Based on the hydrogen sulfide test strip prepared in Example 2, this example provides an application of the hydrogen sulfide test strip in spoiled food, the specific operation of which includes the following steps: Food samples (chicken, pork) such as Figure 8 The sample was placed in a container, and the test strip was then suspended on top of the container. After being sealed for a period of time, the fluorescence change was observed under a 365nm ultraviolet lamp.

[0073] The results showed that no significant fluorescence response was observed in the test paper placed in the fresh sample under 365 nm ultraviolet light irradiation. Figure 8 (Left), while when exposed to hydrogen sulfide gas produced by rotten food samples, the test strip showed a distinct orange fluorescent response (Left). Figure 8 (Right), its fluorescence color change is consistent with the experimental results in the test strip experiment. This further demonstrates that the hydrogen sulfide test strip can achieve visual detection of H2S in spoiled food samples.

[0074] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A fluorescent material for hydrogen sulfide detection, characterized in that, Its chemical name is 2-(5-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-(2,6-dinitrophenoxy)styryl)-3,3-dimethylcyclohexyl-1,5-dien-1-yl)-2-(2,6-dinitrophenyl)malononitrile, and its structural formula is shown in Formula I below: Formula I.

2. A method for preparing a fluorescent material for hydrogen sulfide detection as described in claim 1, characterized in that, Includes the following steps: Synthesis of S1, (E)-5-(2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxybenzaldehyde: N-butyl-2-methylbenzimidazole was mixed with 4-hydroxyisophthalaldehyde and reacted at high temperature to obtain a yellow solid precipitation. The mixture was filtered and the filter cake was washed with anhydrous ethanol to obtain a pale yellow solid (E)-5-(2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxybenzaldehyde; In step S1, the temperature of the high-temperature reaction is 120°C, and the reaction time is 12-18 hours. Synthesis of S2, 2-(3-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxystyryl)-5,5-dimethylcyclohex-2-ene-1-yl)malonitrile: Under an inert atmosphere, (E)-5-(2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxybenzaldehyde obtained in step S1 was dissolved in acetonitrile, and then dicyanoisophorone and piperidine were added and mixed. The mixture was reacted at high temperature to obtain a red solid precipitation. The red solid was recrystallized with anhydrous ethanol to obtain the red solid 2-(3-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxystyryl)-5,5-dimethylcyclohex-2-ene-1-yl)malonitrile; S3. Synthesis of the fluorescent material 2-(5-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-(2,6-dinitrophenoxy)styryl)-3,3-dimethylcyclohex-1,5-dien-1-yl)-2-(2,6-dinitrophenyl)malonadionitrile: Under an inert atmosphere, the 2-(3-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxystyryl)-5 2,3-Dimethylcyclohexyl-2-en-1-yl)malononitrile was dissolved in N,N-dimethylformamide, and mixed with potassium carbonate and 2,4-dinitrofluorobenzene. The mixture was reacted at room temperature, extracted with dichloromethane, and the organic layer was purified by silica gel column chromatography to give a yellow solid 2-(5-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-(2,6-dinitrophenoxy)styryl)-3,3-dimethylcyclohexyl-1,5-dien-1-yl)-2-(2,6-dinitrophenyl)malononitrile.

3. The method for preparing the fluorescent material for hydrogen sulfide detection according to claim 2, characterized in that, In step S1, the molar ratio of N-butyl-2-methylbenzimidazole to 4-hydroxyisophthalaldehyde is 1:(1.1-1.3).

4. The method for preparing the fluorescent material for hydrogen sulfide detection according to claim 2, characterized in that, In step S2, the molar ratio of (E)-5-(2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxybenzaldehyde, dicyanoisophorone, and piperidine is (3-4) mmol:(5-6) mmol:(0.1-0.5) mmol.

5. The method for preparing the fluorescent material for hydrogen sulfide detection according to claim 2, characterized in that, In step S2, the high-temperature reaction temperature is 80°C, and the high-temperature reaction time is 24-36 hours.

6. The method for preparing the fluorescent material for hydrogen sulfide detection according to claim 2, characterized in that, In step S3, the molar ratio of 2-(3-((E)-5-((E)-2-(1-butyl-1H-benzo[d]imidazol-2-yl)vinyl)-2-hydroxystyryl)-5,5-dimethylcyclohex-2-en-1-yl)malononitrile, potassium carbonate, 2,4-dinitrofluorobenzene, and N,N-dimethylformamide is (1-2) mmol:(3-5) mmol:(3-5) mmol:(9-11) mL.

7. The method for preparing the fluorescent material for hydrogen sulfide detection according to claim 2, characterized in that, In step S3, the reaction time at room temperature is 16-24 hours, and the mobile phase used for column chromatography purification is a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 6:

1.

8. An application of the fluorescent material for hydrogen sulfide detection as described in claim 1, characterized in that, The fluorescent material used for hydrogen sulfide detection is dissolved in an aqueous solution of dimethyl sulfoxide to detect hydrogen sulfide.

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

10. The application of a hydrogen sulfide test strip in spoiled food, characterized in that, The hydrogen sulfide is detected using test strips to detect hydrogen sulfide released from spoiled food.

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