A fluorescent probe for bioamine ratio type detection, and a preparation method and application thereof

Abstract

The application provides a fluorescent probe for biological amine ratio type detection and a preparation method and application thereof, and belongs to the technical field of fluorescence sensing. The A-D-A type organic fluorescent small molecule material of the application adopts a conjugated structure containing a hydrogen bond binding site as a donor, and can form an intramolecular charge transfer (ICT) state after introducing an electron-withdrawing group. The purpose of fluorescence detection of biological amine is achieved by the change of ICT properties before and after the hydrogen bond action. The fluorescence detection of biological amine by the material has the advantages of high sensitivity, rapid response, significant color change and reusability. Further, the application also constructs a portable detection platform based on a smart phone. Through digital analysis of the fluorescence image, the visual and quantitative detection of food freshness is realized.

Description

Technical Field

[0001] This invention relates to the field of fluorescence sensing technology, and in particular to a fluorescent probe for the detection of biogenic amine ratios, its preparation method, and its application. Background Technology

[0002] With the widespread global circulation of food, the safety hazards posed by food spoilage have garnered significant attention. To prevent spoiled food from entering the consumer market, monitoring food freshness during transportation and storage is crucial, especially for perishable foods such as seafood. During food spoilage, biogenic amines accumulate through amino acid decomposition and amination reactions; therefore, biogenic amine content is widely recognized as an important indicator for assessing food spoilage. Furthermore, ingesting high concentrations of biogenic amines can trigger adverse reactions such as difficulty breathing, headaches, high blood pressure, vomiting, and even death. Therefore, the detection of biogenic amines in the food supply chain is of great significance for food safety and public health.

[0003] Currently, methods for detecting biogenic amines mainly include gas chromatography-mass spectrometry, high-performance liquid chromatography, and electrochemical detection. However, these methods suffer from slow response, poor selectivity, and complex sample processing, and rely on expensive equipment and specialized technicians, making them unsuitable for real-time on-site detection. Following ion mobility spectrometry, fluorescence sensing technology, recognized as the most promising trace detection technology in the industry, has shown strong momentum and broad application prospects in on-site detection due to its advantages such as sensitivity, lightweight, portability, and high selectivity. Researchers have already developed various fluorescence sensors for detecting biogenic amines. For example, the RFCC fluorescent probe for detecting cadaverine and putrescine, using hydroxylated resorcinol as the chromophore, achieves a red fluorescence activation response; the coumarin-based fluorescent probe JDCN reacts with cadaverine to generate a Schiff base product, which exhibits a very obvious fluorescence color transition from red to green; and the Cl-BDP fluorescent probe for detecting BAs reacts with biogenic amines, where the chlorine atom in the luminescent core is replaced by an amino group, resulting in a product that emits obvious blue fluorescence.

[0004] However, these probes still have some problems, such as: probe signals based on fluorescence intensity changes are not obvious, and it is difficult to exclude interference from photobleaching and background fluorescence; although a few ratiometric fluorescent probes have fluorescence color changes, they usually have the disadvantages of slow response and difficulty in reusability, which limits their application in field detection. To date, no specific fluorescent probe can simultaneously meet the requirements of rapid response, visualization, and reproducible detection of biogenic amines. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a fluorescent probe for ratiometric detection of biogenic amines, its preparation method, and its application. The organic fluorescent small molecule material of this invention has the advantages of ultrafast detection, visualization, and reusability.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides an organic fluorescent small molecule material having the structure shown in any of formulas I to III:

[0008]

[0009] In formula I, Z represents Si, O, or S;

[0010] In equations I to III, R1 is:

[0011]

[0012] Preferably, the organic fluorescent small molecule material has any one of the structures shown in T1 to T11:

[0013]

[0014] This invention also provides a method for preparing the organic fluorescent small molecule material described in the above technical solution, comprising the following steps:

[0015] Compound a, compound b, catalyst, solvent and alkaline reagent were mixed and subjected to Suzuki coupling reaction to obtain the organic fluorescent small molecule material;

[0016] The compound a has a structure shown in any of formulas a1 to a3:

[0017]

[0018] In formula a1, Z represents Si, O, or S;

[0019] In formulas a1 to a3, X is Cl, Br, or I;

[0020] The compound b has a structure shown in any of formulas b1 to b11:

[0021]

[0022] In formulas b1 to b11, Y is a borate group or a borate ester group.

[0023] The present invention also provides a liquid-phase fluorescence sensor, comprising an organic fluorescent molecule and an organic solvent, wherein the organic fluorescent molecule is the organic fluorescent small molecule material described in the above technical solution.

[0024] The present invention also provides a thin-film fluorescence sensor, including a substrate and a fluorescent thin film disposed on the surface of the substrate. The raw materials for preparing the fluorescent thin film include a parent material, a guest material and an organic solvent. The guest material is the organic fluorescent small molecule material described in the above technical solution.

[0025] The present invention also provides a standard fluorescent card for visual semi-quantitative detection of biogenic amines, which is prepared by the thin-film fluorescent sensor described in the above technical solution.

[0026] The present invention also provides the application of the liquid phase fluorescence sensor, thin film fluorescence sensor or standard fluorescence card described in the above technical solution in the detection of biogenic amine fluorescence.

[0027] Preferably, the biogenic amine includes one or more of 1,5-pentanediamine (Cad), 1,4-butanediamine, spermine, spermidine, tryptamine, histamine, diethylamine, and triethylamine.

[0028] Preferably, the application is the visual quantitative fluorescence detection of biogenic amines, which includes the following steps: performing visual quantitative fluorescence detection of biogenic amines by combining the ΔE value and / or RGB value of the fluorescent card image output in real time by a smartphone.

[0029] Preferably, the application is a visual quantitative fluorescence detection of meat sample freshness, including the following steps: performing visual quantitative fluorescence detection of meat sample freshness by combining the ΔE value and / or RGB value of the fluorescent card image output in real time by a smartphone.

[0030] This invention provides an organic fluorescent small molecule material, which is an ADA-type (acceptor-donor-acceptor type) organic fluorescent small molecule material.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] (1) Using diphenylamine, phenothiazine, phenoloxazine, dihydroacrylidine, carbazole, etc. as the main luminescent building blocks and as electron donor groups, they have a rigid planar conjugated structure to ensure high luminescence efficiency. By introducing electron acceptor groups such as fluorine atoms, trifluoromethyl, cyano, and ester groups, intramolecular charge transfer states (ICT) can be formed to construct acceptor-donor-acceptor type organic fluorescent small molecules, and the degree of ICT can be effectively adjusted to regulate its emission wavelength.

[0033] (2) The “NH” on the donor group has the highest electrostatic potential in the entire molecular system. It can form hydrogen bond interactions with electron-rich bioamines through electrostatic attraction, thereby enhancing the ICT properties of the molecule and ultimately causing a red shift in the emission spectrum, thus realizing the visual fluorescence detection of bioamines.

[0034] (3) When donor groups such as diphenylamine, phenothiazine, phenoloxazine, dihydroacridine, and carbazole are linked to electron acceptor groups, the ability of the "NH" site to attract biogenic amines is further increased, thereby further improving the detection sensitivity and response time of the acceptor-donor-acceptor type organic fluorescent small molecules to biogenic amines.

[0035] (4) The acceptor-donor-acceptor type organic fluorescent small molecules detect biogenic amines through hydrogen bonding mechanism, and have excellent reusability, maintaining a high fluorescence response signal after multiple cycles.

[0036] This invention prepares liquid-phase fluorescence sensors and thin-film fluorescence sensors based on the aforementioned organic fluorescent small molecules. Furthermore, by combining the fluorescence images from the liquid-phase fluorescence sensors and thin-film fluorescence sensors with a smartphone for digital analysis, the ΔE or RGB values ​​of the fluorescence images can be output in real time, thereby achieving visualized quantitative detection of biogenic amines and the freshness of actual meat samples. Compared to previously reported fluorescent probes, the acceptor-donor-acceptor type organic fluorescent small molecule material and its thin-film sensor described in this invention can achieve highly efficient fluorescence detection of biogenic amines, while also possessing the characteristics of speed, visualization, and reusability. Attached Figure Description

[0037] Figure 1 The absorption and emission spectra of solutions from T1 to T6 and thin-film fluorescence sensors;

[0038] Figure 2 The absorption and emission spectra of solutions from T9 to T11 and thin-film fluorescence sensors;

[0039] Figure 3 Fluorescence emission spectra of solution fluorescence sensors with different concentrations of cadaverine were obtained for solutions T1 to T4;

[0040] Figure 4 The ratio of fluorescence intensity I after gradually adding other biogenic amines to the fluorescence sensors of solutions T3 and T4. 480 / I 380 and I 520 / I 410 Correlation curve with biogenic amine concentration;

[0041] Figure 5 The time-dependent fluorescence spectra of thin-film fluorescent sensors exposed to saturated cadaverine vapor for T1 to T6 are shown.

[0042] Figure 6 The time-dependent fluorescence spectra of thin-film fluorescent sensors (T9–T11) exposed to saturated cadaverine vapor are shown.

[0043] Figure 7 The ratio I of the fluorescence intensity of the T3 and T4 thin-film fluorescence sensors exposed to biogenic amines and interfering vapors. 470 / I 380 Or I 520 / I 410 Radial histogram;

[0044] Figure 8 The anti-interference test results are for the T3 and T4 thin-film fluorescence sensors;

[0045] Figure 9 The ratio I of fluorescence intensity in the cyclic test results of T3 and T4 thin-film fluorescence sensors. 470 / I 380 Or I 520 / I 410 Radial histogram;

[0046] Figure 10 The fluorescence intensity ratio I of the T3 and T4 thin-film fluorescence sensors 470 / I 380 and I 520 / I 410 Correlation curve with biogenic amine concentration;

[0047] Figure 11 Standard fluorescent cards based on T3 and T4 thin-film fluorescent sensors;

[0048] Figure 12 Visualized quantitative detection results of cadaverine using T3 and T4 thin-film fluorescence sensors;

[0049] Figure 13 The results of the T3 thin-film fluorescence sensor for the visual quantitative detection of the freshness of meat samples;

[0050] Figure 14 This is a visual quantitative detection result of the freshness of meat samples using the T4 thin-film fluorescence sensor. Detailed Implementation

[0051] This invention provides an organic fluorescent small molecule material having the structure shown in any of formulas I to III:

[0052]

[0053] In formula I, Z represents Si, O, or S;

[0054] In equations I to III, R1 is:

[0055]

[0056] In this invention, the organic fluorescent small molecule material preferably has any of the structures shown in T1 to T11:

[0057]

[0058]

[0059] This invention also provides a method for preparing the organic fluorescent small molecule material described in the above technical solution, comprising the following steps:

[0060] Compound a, compound b, catalyst, solvent and alkaline reagent were mixed and subjected to Suzuki coupling reaction to obtain the organic fluorescent small molecule material;

[0061] The compound a has a structure shown in any of formulas a1 to a3:

[0062]

[0063] In formula a1, Z represents Si, O, or S;

[0064] In formulas a1 to a3, X is Cl, Br, or I;

[0065] The compound b has a structure shown in any of formulas b1 to b11:

[0066]

[0067] In formulas b1 to b11, Y is a borate group or a borate ester group.

[0068] Unless otherwise specified, all raw materials used in this invention are commercially available products in the field.

[0069] In this invention, the molar ratio of compound a to compound b is preferably 1:(1 to 10), more preferably 1:(1 to 5), and specifically can be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10.

[0070] In this invention, the catalyst is preferably a palladium catalyst, more preferably tetrakis(triphenylphosphine)palladium, and the molar ratio of compound a to the catalyst is preferably 1:(0.005-0.2), more preferably 1:(0.02-0.13, specifically 1:0.005, 1:0.01, 1:0.02, 1:0.13 or 1:0.2.

[0071] In this invention, the solvent is preferably a mixed solvent of toluene, ethanol and water or a mixed solvent of tetrahydrofuran and water. The volume ratio of toluene, ethanol and water in the mixed solvent of toluene, ethanol and water is preferably 3:2:1, and the volume ratio of tetrahydrofuran and water in the mixed solvent of tetrahydrofuran and water is preferably 2:1. The amount of solvent used is sufficient to ensure that the reaction raw materials are completely dissolved, and this invention does not have any special limitations on this.

[0072] In this invention, the alkaline reagent is preferably potassium carbonate or potassium phosphate, and the molar ratio of compound a to the alkaline reagent is preferably 1:(2-5), more preferably 1:(2.5-3.5), and specifically can be 1:2, 1:2.5, 1:3, 1:3.5, 1:4 or 1:5.

[0073] In this invention, the Suzuki reaction is preferably carried out in a protective atmosphere. This invention does not have any particular limitation on the type of protective gas used to provide the protective atmosphere, and any protective gas well known to those skilled in the art can be used, such as nitrogen or argon.

[0074] In this invention, compound a, compound b, a solvent, and a basic reagent are mixed. The mixture is then frozen and evacuated. Next, under a protective atmosphere, the resulting mixture is mixed with a catalyst. The resulting mixture is then frozen and evacuated three times. The preferred freezing time is 10 minutes, and the preferred evacuation time is 5 minutes. In this invention, the freezing is preferably performed with liquid nitrogen. By employing the above-described feeding sequence and the pretreatment method of freezing and evacuation, oxygen in the reaction system can be removed as much as possible to avoid oxidative deactivation of the palladium catalyst.

[0075] In this invention, the temperature of the Suzuki reaction is preferably 70 to 100°C, specifically 70, 80, 90 or 100°C; the time is preferably 24 to 48 hours, more preferably 24 to 36 hours, specifically 24, 36 or 48 hours.

[0076] After the Suzuki reaction is completed, the present invention preferably cools the obtained product system naturally and then extracts it with dichloromethane. The obtained organic phase is washed with water and dried with anhydrous sodium sulfate, filtered, concentrated and purified by column chromatography to obtain the organic fluorescent small molecule material.

[0077] In this invention, the eluent used for column chromatography purification is preferably a dichloromethane-petroleum ether mixture or an ethyl acetate-petroleum ether mixture; the volume ratio of dichloromethane to petroleum ether in the dichloromethane-petroleum ether mixture is preferably 1:1 to 4, specifically 1:1, 1:2, 1:3 or 1:4; the volume ratio of ethyl acetate to petroleum ether in the ethyl acetate-petroleum ether mixture is preferably 1:3 to 6, specifically 1:3, 1:4, 1:5 or 1:6.

[0078] The present invention also provides a liquid-phase fluorescence sensor, comprising an organic fluorescent molecule and an organic solvent, wherein the organic fluorescent molecule is the organic fluorescent small molecule material described in the above technical solution.

[0079] In this invention, the organic solvent preferably includes one or more of cyclohexane, tetrahydrofuran, dichloromethane and acetone, more preferably acetone.

[0080] In this invention, the concentration of the organic fluorescent small molecule material in the liquid-phase fluorescence sensor is preferably 0.5–2 mg / mL, more preferably 1–1.5 mg / mL, specifically 0.5, 1, 1.5, or 2 mg / mL. This invention does not have special requirements for the amount of solvent used or the preparation method of the liquid-phase fluorescence sensor; the organic fluorescent small molecule material can be directly dissolved.

[0081] The present invention also provides a method for using the liquid-phase fluorescence sensor to detect biogenic amines, preferably comprising the following steps:

[0082] The test solution is added to the liquid-phase fluorescence sensor, and the changes in fluorescence emission spectrum and fluorescence color of the liquid-phase fluorescence sensor are observed. If the original maximum fluorescence emission peak of the liquid-phase fluorescence sensor gradually weakens or a new emission peak is generated at a long wavelength, accompanied by a significant color change or quenching response in the fluorescence color, then it is determined that the test solution contains biogenic amines.

[0083] The present invention also provides a thin-film fluorescence sensor, including a substrate and a fluorescent thin film disposed on the surface of the substrate. The raw materials for preparing the fluorescent thin film include a parent material, a guest material and an organic solvent. The guest material is the organic fluorescent small molecule material described in the above technical solution.

[0084] In this invention, the substrate is preferably a transparent substrate, more preferably a glass plate, a quartz plate, or an indium tin oxide (ITO) plate. This invention does not impose any particular limitation on the thickness of the substrate; any thickness well-known to those skilled in the art can be used.

[0085] In this invention, the thickness of the fluorescent film is preferably 20-150 nm, more preferably 50-100 nm, and even more preferably 60-80 nm.

[0086] In this invention, the parent material preferably includes one or more of polymethyl methacrylate, polyethyl methacrylate, polycarbonate and polyvinyl chloride, and more preferably polymethyl methacrylate.

[0087] In this invention, the organic fluorescent small molecule material is used as a guest material and is doped into the parent material to prepare a fluorescent thin film.

[0088] In this invention, the mass ratio of the guest material to the parent material is preferably 5-50:100, more preferably 20-40:100. The parent material in this invention disperses the guest material, ensuring that the fluorescent film exhibits better fluorescence luminescence performance.

[0089] In this invention, the organic solvent preferably includes one or more of toluene, chlorobenzene, chloroform, dichloromethane, tetrahydrofuran, and o-dichlorobenzene, more preferably tetrahydrofuran; in a specific embodiment of this invention, the volume ratio of the total mass of the guest material and the parent material to the organic solvent is preferably (0.5-50) mg:1 mL, more preferably (5-30) mg:1 mL, and even more preferably (5-15) mg:1 mL.

[0090] In this invention, the method for fabricating the thin-film fluorescence sensor preferably includes the following steps:

[0091] The object material, the parent material, and the organic solvent are mixed to obtain a mixed raw material;

[0092] The mixed raw materials are coated on one side of a substrate, and after drying, a fluorescent thin film is formed on the surface of the substrate to obtain the thin film fluorescent sensor.

[0093] In this invention, the substrate is preferably cleaned before use to remove surface impurities. The cleaning process is preferably carried out in sequence as water washing, ethanol washing, acetone washing, and toluene washing. The cleaning process is preferably carried out under ultrasonic conditions, and the ultrasonic cleaning time for each cleaning solution is preferably 15 minutes.

[0094] In this invention, the coating method is preferably spin coating, which is preferably carried out in a spin coater; the spin coating speed is preferably 1000-2000 r / min, more preferably 1500-2000 r / min; and the spin coating time is preferably 25-35 s, more preferably 28-30 s.

[0095] In this invention, the drying method is preferably air drying at room temperature or vacuum drying, more preferably vacuum drying; the vacuum drying temperature is preferably 40-50°C, more preferably 45°C; and the vacuum drying time is preferably 10-70 min, more preferably 30-60 min.

[0096] The present invention also provides a method for using the thin-film fluorescence sensor to detect biogenic amines, preferably comprising the following steps:

[0097] The thin-film fluorescent sensor was placed in a biogenic amine gas, and irradiated with a 365nm ultraviolet lamp. The visible changes in the fluorescence color of the thin-film fluorescent sensor were observed, and the spectrum of the thin-film sensor was recorded using a fluorescence spectrometer. The changes in the fluorescence emission spectrum of the thin-film fluorescent sensor were observed. If the fluorescence emission spectrum showed a redshift (greater than 80nm) accompanied by an instantaneous change in the fluorescence color of the thin-film sensor, it was determined that the gas to be tested contained biogenic amine gas.

[0098] The present invention also provides a standard fluorescent card for visual semi-quantitative detection of biogenic amines, which is prepared by the thin-film fluorescent sensor described in the above technical solution.

[0099] In this invention, the use of the standard fluorescent cards preferably includes the following steps: placing the thin-film fluorescent sensor in biogenic amine vapors of different concentrations (0–132 ppm), and identifying thin-film fluorescent sensors with distinctly different fluorescence colors (1.5 ppm, 3 ppm, 6 ppm, 12 ppm, 24 ppm, 48 ppm) as standard fluorescent cards. This invention, by placing the thin-film fluorescent sensor in an atmosphere of unknown biogenic amine concentration and comparing the fluorescence colors on different fluorescent cards under a 365 nm ultraviolet lamp, can determine the concentration of biogenic amine in an unknown gas, enabling real-time and rapid on-site determination of biogenic amine concentration, which has significant commercial application value and importance.

[0100] The present invention also provides the application of the liquid phase fluorescence sensor, thin film fluorescence sensor or standard fluorescence card described in the above technical solution in the detection of biogenic amine fluorescence.

[0101] In this invention, the biogenic amine preferably includes one or more of 1,5-pentanediamine (cadaverine), 1,4-butanediamine (putrescine), spermine, spermidine, tryptamine, histamine, diethylamine, and triethylamine.

[0102] In this invention, the application is preferably the visual quantitative fluorescence detection of biogenic amines, which preferably includes the following steps: performing visual quantitative fluorescence detection of biogenic amines by combining the ΔE value and / or RGB value of the fluorescent card image output in real time by a smartphone.

[0103] In this invention, the application is preferably a visual quantitative fluorescence detection of the freshness of meat samples, which preferably includes the following steps: performing visual quantitative fluorescence detection of the freshness of meat samples by combining the ΔE value and / or RGB value of the fluorescent card image output in real time by a smartphone.

[0104] In this invention, the visualized quantitative fluorescence detection preferably uses a thin-film fluorescence sensor or a standard fluorescence card.

[0105] This invention provides a method for visually and quantitatively detecting biogenic amines using a smartphone. Taking cadaverine as an example, the preferred method includes the following steps:

[0106] (1) The thin film fluorescence sensor described in this invention is placed in cadaverine gas of different concentrations, and the fluorescence image of the fluorescent thin film is acquired by a smartphone and the ΔE and / or RGB values ​​of the fluorescence image are output in real time. The ΔE (color difference) and / or G value (green channel) are linearly fitted with the concentration of cadaverine to obtain a standard curve.

[0107] (2) Place the thin-film fluorescence sensor in an unknown gas containing cadaverine, use a smartphone to acquire a fluorescence image of the fluorescent thin film and output the ΔE and / or G values ​​of the fluorescence image in real time, substitute them into the standard curve obtained in step (1), and calculate the concentration of cadaverine in the unknown gas.

[0108] In this invention, the linear range of the standard curve is preferably 1.5 to 12 ppm; RGB refers to the values ​​of the red, green, and blue channels in the fluorescence image; and ΔE is the color coordinate value in the CIELab color space, calculated as shown in equation (1):

[0109] ΔE=dC=[(L2 * -L1 * ) 2 +(a2 * -a1 * ) 2 +(b2 * -b1 * ) 2 ] 1 / 2 Equation (1),

[0110] In the formula: L represents the brightness of the color, usually ranging from 0 to 100; L* = 0 represents complete black, L* = 100 represents complete white; a represents the color offset between red and green, ranging from positive to negative values: a* > 0: leaning towards red, a* < 0: leaning towards green; b represents the color offset between yellow and blue, ranging from positive to negative values: b* > 0: leaning towards yellow, b* < 0: leaning towards blue.

[0111] Taking meat samples (preferably including shrimp, pork, or beef) as an example, the preferred steps for visual quantitative detection of food freshness are:

[0112] (1) Place the meat samples to be tested in different storage environments and measure the volatile basic nitrogen (TVBN) in the meat samples at fixed intervals.

[0113] (2) Place the thin film fluorescence sensor described in this invention together with the meat sample to be tested and store them in different environments. Use a smartphone to take fluorescence images of the fluorescent film at fixed intervals and output the fluorescence image ΔE in real time. Linearly fit ΔE with the TVBN value measured in step (1) to obtain a standard curve.

[0114] (3) Place the thin film fluorescence sensor in the meat sample to be tested, use a smartphone to take a fluorescence image of the fluorescent film and output the ΔE value, substitute the obtained ΔE into the standard curve obtained in step (2) to obtain the TVBN value in the meat sample to be tested, and compare it with the international standard to determine the freshness of the meat sample to be tested.

[0115] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0116] Example 1

[0117] The reaction formula for preparing T1 is shown below:

[0118]

[0119] 357 mg of compound a1 (1 mmol), 437 mg of b2 (2.3 mmol), 345 mg of potassium carbonate (K2CO3) (2.5 mmol), 12 mL of toluene, 8 mL of water, and 4 mL of anhydrous ethanol were placed in a polymerization flask. After sealing, the mixture in the double-necked flask was frozen for 8 min with liquid nitrogen, followed by evacuation for 5 min. The mixture was then allowed to return to room temperature under sealed conditions. Then, 57 mg of tetra(triphenylphosphine)palladium catalyst was added under argon protection. The freezing-evacuation operation was repeated three times to remove oxygen. After the operation, the reaction temperature was raised to 90 °C and the reaction was allowed to proceed for 24 h. After the reaction was completed, heating was stopped, and the resulting product system was allowed to cool naturally to room temperature and then transferred to a separatory funnel. The product system was extracted with dichloromethane. The resulting organic layer was washed with water and dried with anhydrous sodium sulfate, filtered, concentrated, and then purified by column chromatography (the eluent used was dichloromethane:petroleum ether = 1:3 by volume). The resulting green solid was T1, with a yield of 52%.

[0120] 1 H NMR (500MHz, DMSO) δ9.03 (s, 1H), 7.83 (d, J=8.2Hz, 4H), 7.75 (d, J=8.3Hz, 4H), 7.42 (d, J=6.4Hz, 2H), 7.37 (s, 2H), 6.80 (d, J=8.3Hz, 2H).

[0121] Mass spectrometry molecular ion peak: 487.8218.

[0122] Example 2

[0123] The reaction formula for preparing T2 is shown below:

[0124]

[0125] 654 mg of compound a2 (2 mmol), 873 mg of b2 (4.6 mmol), 690 mg of potassium carbonate (K2CO3) (5 mmol), 15 mL of toluene, 10 mL of water, and 5 mL of anhydrous ethanol were placed in a polymerization flask. After sealing, the mixture in the double-necked flask was frozen for 8 min with liquid nitrogen, then evacuated for 5 min. The mixture was then allowed to return to room temperature under sealed conditions. Then, 231 mg of tetra(triphenylphosphine)palladium catalyst was added under argon protection. The freezing-evacuation operation was repeated three times to remove oxygen. After the operation, the reaction was heated to 90 °C and reacted for 24 h. After the reaction was completed, heating was stopped, and the resulting product system was allowed to cool naturally to room temperature and then transferred to a separatory funnel. The product system was extracted with dichloromethane. The resulting organic layer was washed with water and dried with anhydrous sodium sulfate, filtered, concentrated, and then purified by column chromatography (the eluent used was dichloromethane:petroleum ether = 2:3 by volume). The resulting white solid was T2, with a yield of 64%.

[0126] 1 H NMR (500MHz, DMSO) δ 8.71 (s, 1H), 7.87 (d, J = 8.2Hz, 4H), 7.77 (d, J = 8.4Hz, 4H), 7.70 (d, J = 8.6Hz, 4H), 7.27 (d, J = 8.6Hz, 4H).

[0127] Mass spectrometry molecular ion peak: 457.0053.

[0128] Example 3

[0129] The reaction formula for preparing T3 is shown below:

[0130]

[0131] 325 mg of compound a3 (1 mmol), 570 mg of b2 (3 mmol), 414 mg of potassium carbonate (K2CO3) (3 mmol), 12 mL of toluene, 8 mL of water, and 4 mL of anhydrous ethanol were placed in a polymerization flask. After sealing, the mixture in the double-necked flask was frozen for 8 min with liquid nitrogen, followed by evacuation for 5 min. The mixture was then allowed to return to room temperature under sealed conditions. Then, 57 mg of tetra(triphenylphosphine)palladium catalyst was added under argon protection. The freezing-evacuation operation was repeated three times to remove oxygen. After the operation, the reaction was heated to 80 °C and reacted for 24 h. After the reaction was completed, heating was stopped, and the resulting product system was allowed to cool naturally to room temperature and then transferred to a separatory funnel. The product system was extracted with dichloromethane. The resulting organic layer was washed with water and dried with anhydrous sodium sulfate, filtered, concentrated, and then purified by column chromatography (the eluent used was ethyl acetate:petroleum ether = 1:4 by volume). The resulting white solid was T3, with a yield of 60%.

[0132] 1 H NMR (500MHz, DMSO) δ 11.59 (s, 1H), 8.73 (s, 2H), 8.04 (d, J=8.2Hz, 4H), 7.85 (d, J=8.4Hz, 6H), 7.65 (d, J=8.5Hz, 2H).

[0133] Mass spectrometry molecular ion peak: 455.9268.

[0134] Example 4

[0135] The reaction formula for preparing T4 is shown below:

[0136]

[0137] 325 mg of compound a3 (1 mmol), 441 mg of b3 (3 mmol), 414 mg of potassium carbonate (K2CO3) (3 mmol), 12 mL of toluene, 8 mL of water, and 4 mL of anhydrous ethanol were placed in a polymerization flask. After sealing, the mixture in the double-necked flask was frozen for 8 min with liquid nitrogen, followed by evacuation for 5 min. The mixture was then allowed to return to room temperature under sealed conditions. Then, 57 mg of tetra(triphenylphosphine)palladium catalyst was added under argon protection. The freezing-evacuation operation was repeated three times to remove oxygen. After the operation, the reaction temperature was raised to 80 °C and the reaction was allowed to proceed for 24 h. After the reaction was completed, heating was stopped, and the resulting product system was allowed to cool naturally to room temperature and then transferred to a separatory funnel. The product system was extracted with dichloromethane. The resulting organic layer was washed with water and dried over anhydrous sodium sulfate, filtered, concentrated, and then purified by column chromatography (the eluent used was ethyl acetate:petroleum ether = 1:1 by volume). The resulting white solid was T4, with a yield of 60%.

[0138] 1 H NMR (500MHz, DMSO) δ 11.64 (s, 1H), 8.77 (s, 2H), 8.03 (d, J=8.1Hz, 4H), 7.96 (d, J=8.0Hz, 4H), 7.86 (d, J=8.4Hz, 2H), 7.64 (d, J=8.4Hz, 2H).

[0139] Mass spectrometry molecular ion peak: 369.1904.

[0140] Example 5

[0141] The reaction formula for preparing T5 is shown below:

[0142]

[0143] 682 mg of compound a4 (2 mmol), 644 mg of b1 (4.6 mmol), 690 mg of potassium carbonate (K2CO3) (5 mmol), 15 mL of toluene, 10 mL of water, and 5 mL of anhydrous ethanol were placed in a polymerization flask. After sealing, the mixture in the double-necked flask was frozen for 8 min with liquid nitrogen, followed by evacuation for 5 min. The mixture was then allowed to return to room temperature under sealed conditions. Then, 231 mg of tetra(triphenylphosphine)palladium catalyst was added under argon protection. The freezing-evacuation operation was repeated three times to remove oxygen. After the operation, the reaction was heated to 90 °C and reacted for 24 h. After the reaction was completed, heating was stopped, and the resulting product system was allowed to cool naturally to room temperature and then transferred to a separatory funnel. The product system was extracted with dichloromethane. The resulting organic layer was washed with water and dried with anhydrous sodium sulfate, filtered, concentrated, and then purified by column chromatography (the eluent used was dichloromethane:petroleum ether = 1:3 by volume). The resulting white solid was T5, with a yield of 74%.

[0144] 1 H NMR (500MHz, DMSO) δ8.52 (s, 1H), 7.61 (dd, J=8.7, 5.5Hz, 4H), 7.22 (t, J=8.8Hz , 4H), 7.07 (dd, J=8.1, 1.9Hz, 2H), 6.95 (d, J=1.8Hz, 2H), 6.56 (d, J=8.1Hz, 2H)

[0145] Mass spectrometry molecular ion peak: 371.0512.

[0146] Example 6

[0147] The reaction formula for preparing T6 is shown below:

[0148]

[0149] 682 mg of compound a4 (2 mmol), 873 mg of b2 (4.6 mmol), 690 mg of potassium carbonate (K2CO3) (6 mmol), 15 mL of toluene, 10 mL of water, and 5 mL of anhydrous ethanol were placed in a polymerization flask. After sealing, the mixture in the double-necked flask was frozen for 8 min with liquid nitrogen, followed by evacuation for 5 min. The mixture was then allowed to return to room temperature under sealed conditions. Then, 231 mg of tetra(triphenylphosphine)palladium catalyst was added under argon protection. The freezing-evacuation operation was repeated three times to remove oxygen. After the operation, the reaction was heated to 90 °C and reacted for 24 h. After the reaction was completed, heating was stopped, and the resulting product system was allowed to cool naturally to room temperature and then transferred to a separatory funnel. The product system was extracted with dichloromethane. The resulting organic layer was washed with water and dried with anhydrous sodium sulfate, filtered, concentrated, and then purified by column chromatography (the eluent used was dichloromethane:petroleum ether = 2:3 by volume). The resulting light yellow solid was T6, with a yield of 60%.

[0150] 1 H NMR (500MHz, DMSO) δ 8.75 (s, 1H), 7.81 (d, J = 8.2Hz, 4H), 7.74 (d, J = 8.3Hz, 4H), 7.20 (dd, J = 8.1, 1.9Hz, 2H), 7.07 (d, J = 1.7Hz, 2H), 6.61 (d, J = 8.1Hz, 2H).

[0151] Mass spectrometry molecular ion peak: 471.1788.

[0152] Example 7

[0153] The reaction formula for preparing T7 is shown below:

[0154]

[0155] 654 mg of compound a2 (2 mmol), 882 mg of b3 (6 mmol), 828 mg of potassium carbonate (K2CO3) (6 mmol), 15 mL of toluene, 10 mL of water, and 5 mL of anhydrous ethanol were placed in a polymerization flask. After sealing, the mixture in the double-necked flask was frozen for 8 min with liquid nitrogen, followed by evacuation for 5 min. The mixture was then allowed to return to room temperature under sealed conditions. Then, 231 mg of tetra(triphenylphosphine)palladium catalyst was added under argon protection. The freezing-evacuation operation was repeated three times to remove oxygen. After the operation, the reaction temperature was raised to 90 °C and the reaction was allowed to proceed for 24 h. After the reaction was completed, heating was stopped, and the resulting product system was allowed to cool naturally to room temperature and then transferred to a separatory funnel. The product system was extracted with dichloromethane. The resulting organic layer was washed with water and dried with anhydrous sodium sulfate, filtered, concentrated, and then purified by column chromatography (the eluent used was dichloromethane:petroleum ether = 1:1 by volume). The resulting white solid was T7, with a yield of 56%.

[0156] 1 H NMR (500MHz, DMSO) δ 8.76 (s, 1H), 7.91 (d, J = 8.2Hz, 4H), 7.78 (d, J = 8.4Hz, 4H), 7.70 (d, J = 8.6Hz, 4H), 7.27 (d, J = 8.6Hz, 4H).

[0157] Mass spectrometry molecular ion peak: 371.1843.

[0158] Example 8

[0159] The reaction formula for preparing T8 is shown below:

[0160]

[0161] 654 mg of compound a2 (2 mmol), 668 mg of b4 (4 mmol), 414 mg of potassium carbonate (K2CO3) (3 mol), 15 mL of toluene, 10 mL of water, and 5 mL of anhydrous ethanol were placed in a polymerization flask. After sealing, the mixture in the double-necked flask was frozen for 8 min with liquid nitrogen, followed by evacuation for 5 min. The mixture was then allowed to return to room temperature under sealed conditions. Then, 231 mg of tetra(triphenylphosphine)palladium catalyst was added under argon protection. The freezing-evacuation operation was repeated three times to remove oxygen. After the operation, the reaction was heated to 90 °C and reacted for 24 h. After the reaction was completed, heating was stopped, and the resulting product system was allowed to cool naturally to room temperature and then transferred to a separatory funnel. The product system was extracted with dichloromethane. The resulting organic layer was washed with water and dried with anhydrous sodium sulfate, filtered, concentrated, and then purified by column chromatography (the eluent used was dichloromethane:petroleum ether = 1:1 by volume). The resulting red solid was T8, with a yield of 40%.

[0162] 1 H NMR (500MHz, DMSO) δ 8.84 (s, 1H), 7.96 (d, J = 8.2Hz, 4H), 7.80 (d, J = 8.4Hz, 4H), 7.73 (d, J = 8.6Hz, 4H), 7.27 (d, J = 8.6Hz, 4H).

[0163] Mass spectrometry molecular ion peak: 411.3687.

[0164] Example 9

[0165] The reaction formula for preparing T9 is shown below:

[0166]

[0167] 325 mg of compound a3 (1 mmol), 540 mg of b5 (3 mmol), 414 mg of potassium carbonate (K2CO3) (3 mmol), 12 mL of toluene, 8 mL of water, and 4 mL of anhydrous ethanol were placed in a polymerization flask. After sealing, the mixture in the double-necked flask was frozen for 8 min with liquid nitrogen, followed by evacuation for 5 min. The mixture was then allowed to return to room temperature under sealed conditions. Then, 57 mg of tetra(triphenylphosphine)palladium catalyst was added under argon protection. The freezing-evacuation operation was repeated three times to remove oxygen. After the operation, the reaction was heated to 80 °C and reacted for 24 h. After the reaction was completed, heating was stopped, and the resulting product system was allowed to cool naturally to room temperature and then transferred to a separatory funnel. The product system was extracted with dichloromethane. The resulting organic layer was washed with water and dried with anhydrous sodium sulfate, filtered, concentrated, and then purified by column chromatography (the eluent used was dichloromethane:petroleum ether = 1:1 by volume). The resulting light yellow solid was T9, with a yield of 66%.

[0168] 1 H NMR (500MHz, DMSO) δ 11.58 (s, 1H), 8.76 (d, J = 1.5Hz, 2H), 8.08 (d, J = 8.5Hz, 4H), 7.9 9 (d, J=8.5Hz, 4H), 7.86 (dd, J=8.5, 1.8Hz, 2H), 7.63 (d, J=8.5Hz, 2H), 3.90 (s, 6H).

[0169] Mass spectrometry molecular ion peak: 435.4790.

[0170] Example 10

[0171] The reaction formula for preparing T10 is shown below:

[0172]

[0173] 325 mg of compound a3 (1 mmol), 369 mg of b6 (3 mmol), 414 mg of potassium carbonate (K2CO3) (3 mmol), 12 mL of toluene, 8 mL of water, and 4 mL of anhydrous ethanol were placed in a polymerization flask. After sealing, the mixture in the double-necked flask was frozen for 8 min with liquid nitrogen, followed by evacuation for 5 min. The mixture was then allowed to return to room temperature under sealed conditions. Then, 57 mg of tetra(triphenylphosphine)palladium catalyst was added under argon protection. The freezing-evacuation operation was repeated three times to remove oxygen. After the operation, the reaction was heated to 80 °C and reacted for 24 h. After the reaction was completed, heating was stopped, and the resulting product system was allowed to cool naturally to room temperature and then transferred to a separatory funnel. The product system was extracted with dichloromethane. The resulting organic layer was washed with water and dried with anhydrous sodium sulfate, filtered, concentrated, and then purified by column chromatography (the eluent used was dichloromethane:tetrahydrofuran = 5:1 by volume). The resulting light yellow solid was T10, with a yield of 59%.

[0174] 1 H NMR (500MHz, DMSO) δ 11.67 (s, 1H), 8.84 (s, 2H), 8.66 (d, J = 5.9Hz, 4H), 7.93 (d, J = 8.5Hz, 2H), 7.86 (d, J = 6.1Hz, 4H), 7.66 (d, J = 8.5Hz, 2H).

[0175] Mass spectrometry molecular ion peak: 321.9365.

[0176] Example 11

[0177] The reaction formula for preparing T11 is shown below:

[0178]

[0179] 325 mg of compound a3 (1 mmol), 372 mg of b7 (3 mmol), 414 mg of potassium carbonate (K2CO3) (3 mmol), 10 mL of tetrahydrofuran, and 5 mL of water were placed in a polymerization flask. After sealing, the mixture in the double-necked flask was frozen for 8 min with liquid nitrogen, then evacuated for 5 min. The mixture was then restored to room temperature under sealed conditions. Then, 57 mg of tetra(triphenylphosphine)palladium catalyst was added under argon protection. The freezing-evacuation operation was repeated three times to remove oxygen. After the operation, the reaction temperature was raised to 80 °C and the reaction was carried out for 24 h. After the reaction was completed, heating was stopped, and the resulting product system was allowed to cool naturally to room temperature and then filtered under reduced pressure. The filter cake was washed three times with tetrahydrofuran. The resulting light yellow solid was T11, with a yield of 70%.

[0180] 1H NMR (500MHz, DMSO) δ 11.76 (s, 1H), 9.36 (s, 2H), 9.12 (d, J = 5.9Hz, 4H), 7.99 (d, J = 8.5Hz, 2H), 7.89 (d, J = 6.1Hz, 2H), 7.71 (d, J = 8.5Hz, 2H).

[0181] Mass spectrometry molecular ion peak: 323.1290.

[0182] Example 12

[0183] Preparation of solution fluorescence sensors based on T1–T4: Compounds T1–T4 obtained in Examples 1–4 were mixed with acetone to prepare a solution with a concentration of 1 × 10⁻⁶. -6 A solution of mol / L acetone was prepared by placing 3 mL of the solution (T1-T4) into a quartz cuvette to obtain a solution fluorescence sensor.

[0184] Example 13

[0185] Preparation of thin-film fluorescent sensors based on T1 to T11: Quartz sheets were selected as substrates and ultrasonically cleaned for 15 min each with water, ethanol, acetone, and toluene, respectively, for later use. 2 mg of compounds T1 to T11 obtained in Examples 1 to 11 were used as guest materials and dissolved in 1 mL of tetrahydrofuran with 4.75 mg of the parent material (polymethyl methacrylate, PMMA). 60 μL of the resulting mixture was drop-coated onto the cleaned quartz sheet surface. Thin films were prepared by spin-coating using a spin coater at a speed of 1500 r / min for 30 s. Finally, the films were vacuum-dried at 45 °C for 30 min to form fluorescent films with a thickness of 60 nm on the substrate surface, denoted as T1 to T11 fluorescent films.

[0186] Test Example 1

[0187] Dissolving T1 to T6 in dichloromethane yields a solution with a concentration of 1×10⁻⁶. -6 The absorption and emission spectra of a mol / L dichloromethane solution were recorded using a UV absorption spectrometer and a fluorescence emission spectrometer, respectively, and compared with the emission spectra of the T1–T6 fluorescent films. The results are as follows: Figure 1 As shown. Figure 1 In the figures (a), (b), (c), (d), (e), and (f), the absorption and emission spectra of the solution and the thin-film fluorescence sensor at times T1, T2, T3, T4, T5, and T6, respectively. The curves on the left represent the absorption spectrum, and the curves on the right represent the emission spectrum; the solid lines represent the solution, and the dashed lines represent the thin film.

[0188] Depend on Figure 1It can be seen that T1, T5, and T6 exhibit single absorption peaks in solution, with maximum absorption wavelengths of 350 nm, 360 nm, and 380 nm, respectively. T2–T4 show strong absorption peaks in the short-wavelength region (approximately 300 nm) and shoulder peaks in the long-wavelength region (320–350 nm) in solution. The emission peaks of T1–T6 in solution are located at 410 nm, 490 nm, 380 nm, 410 nm, 430 nm, and 460 nm, respectively. The emission in the thin film state is similar to that in solution, with peak values ​​varying within the range of 10 nm.

[0189] Test Example 2

[0190] Dissolving T9 to T11 in dichloromethane yields a solution with a concentration of 1×10⁻⁶. -6 The absorption and emission spectra of a mol / L dichloromethane solution were recorded using a UV absorption spectrometer and a fluorescence emission spectrometer, respectively, and compared with the emission spectra of the T9-T11 fluorescent films. The results are as follows: Figure 2 As shown. Figure 2 In the figures (a), (b), and (c), the absorption and emission spectra of the solutions at T9, T10, and T11, and the thin-film fluorescence sensor, respectively, are shown. The curves on the left represent the absorption spectra, and the curves on the right represent the emission spectra; the solid lines represent the solutions, and the dashed lines represent the thin films.

[0191] Depend on Figure 2 It can be seen that the absorption spectra of T9 to T11 in solution exhibit absorption peaks in the short wavelength region (approximately 300 nm) and absorption characteristics in the long wavelength region (320–375 nm). The emission peaks of T9 to T11 in solution are located at 405 nm, 370 nm, and 430 nm, respectively. The emission in the thin film state is similar to that in solution, with peak values ​​varying within the range of 10 nm.

[0192] Test Example 3

[0193] The detection performance of solution fluorescence sensors (T1-T4) for biogenic amines:

[0194] Taking cadaverine as an example, cadaverine (concentration range of 0-10 μM) was gradually added to the T1-T4 solution fluorescence sensors prepared in Example 12, and the changes in fluorescence spectra were observed. The results are as follows: Figure 3 As shown. Figure 3 In the middle (a), (b), (c), and (d), the fluorescence emission spectra of the solution fluorescence sensors at T1, T2, T3, and T4 after adding different concentrations of cadaverine are shown.

[0195] It can be seen that the emission peak of the T1 solution fluorescence sensor gradually weakens at 410 nm, and no new peaks are observed at longer wavelengths. Further analysis of I... 410Correlation with biogenic amine concentration yielded a detection limit (LOD) of 1380 nM. The T2 solution fluorescence sensor showed a gradual decrease in emission peak at 490 nm and a gradual increase in emission peak at 630 nm. Further analysis of I... 630 / I 490 The correlation with biogenic amine concentration yielded a calculated LOD of 31 nM. The T3 solution fluorescence sensor showed a gradual decrease in emission peak at 380 nm, followed by a significant increase in emission peak at 470 nm. Further analysis revealed... 480 / I 380 The correlation with biogenic amine concentration yielded a calculated LOD of 14 nM. The T4 solution fluorescence sensor showed a gradually decreasing emission peak at 410 nm and a gradually increasing emission peak at 520 nm. Further analysis revealed... 520 / I 410 The correlation with biogenic amine concentration yielded a calculated LOD of 23 nM.

[0196] Test Example 4

[0197] The detection performance of T3 and T4 solution fluorescence sensors for other biogenic amines:

[0198] After gradually adding putrescine, spermine, spermidine, tryptamine, histamine, diethylamine, and triethylamine (concentration range 0–10 μM) to the T3 and T4 solution fluorescence sensors prepared in Example 12, the changes in emission spectra were recorded and analyzed. The results are as follows: Figure 4 As shown. Figure 4 In the middle (a) and (b), the fluorescence intensity ratios I after gradually adding other biogenic amines to the fluorescence sensors of solutions T3 and T4 are shown respectively. 480 / I 380 and I 520 / I 410 Correlation curve with biogenic amine concentration.

[0199] It can be seen that the solution fluorescence sensors of T3 and T4 have similar fluorescence responses to other biogenic amines as cadaverine, and the fitting curves show a good linear relationship within the test range.

[0200] Test Example 5

[0201] Gas-phase detection of biogenic amines using T1–T6 thin-film fluorescence sensors:

[0202] Taking cadaverine as an example, the T1 to T6 thin-film fluorescence sensors prepared in Example 13 were placed in a quartz cell containing cadaverine saturated vapor. The fluorescence spectrum changes of the thin film were recorded once every 5 seconds using a fluorescence spectrometer. At the same time, the color changes under ultraviolet light irradiation were observed. The results are as follows: Figure 5 As shown. Figure 5In the middle (a) to (f), the time-dependent fluorescence spectra of the thin-film fluorescent sensors exposed to saturated cadaverine vapor are T1 to T6, respectively. The insets show the fluorescence images of the corresponding thin-film fluorescent sensors before and after exposure.

[0203] It can be seen that the thin-film fluorescent sensor responds instantaneously to cadaverine, with varying degrees of redshift in the fluorescence emission spectrum: 135 nm for T1, 160 nm for T2, 90 nm for T3, 110 nm for T4, 125 nm for T5, and 150 nm for T6, accompanied by significant changes in fluorescence color. As time progresses, the emission spectrum does not continue to redshift. This indicates that the thin-film fluorescent sensor with values ​​from T1 to T6 can detect cadaverine gas, exhibiting advantages such as rapid response and significant color changes.

[0204] Test Example 6

[0205] Gas-phase detection of biogenic amines using T9-T11 thin-film fluorescence sensors:

[0206] Taking cadaverine as an example, the T9 to T11 thin-film fluorescence sensors prepared in Example 13 were placed in a quartz cell containing saturated cadaverine vapor. The fluorescence spectrum changes of the thin film were recorded once every 5 seconds using a fluorescence spectrometer. At the same time, the color changes under ultraviolet light irradiation were observed. The results are as follows: Figure 6 As shown. Figure 6 In the middle (a) to (c), the time-dependent fluorescence spectra of the thin-film fluorescent sensors of T9 to T11 exposed to saturated cadaverine vapor are shown respectively. The inset shows the fluorescence images of the corresponding thin-film fluorescent sensors before and after exposure.

[0207] It can be seen that the thin-film fluorescent sensor responds instantly to cadaverine, with varying degrees of redshift in the fluorescence emission spectrum: 100 nm for T9, 80 nm for T10, and 95 nm for T11, accompanied by significant changes in fluorescence color. As time progresses, the emission spectrum does not continue to redshift. This indicates that the T9–T11 fluorescent thin films can detect cadaverine gas, offering advantages such as rapid response and significant color changes.

[0208] Test Example 7

[0209] Selectivity of T3 and T4 thin-film fluorescence sensors for gas-phase detection of biogenic amines:

[0210] The T3 and T4 thin-film fluorescent sensors prepared in Example 13 were placed in saturated gases of cadaverine, putrescine, tetrahydropyrrole, spermine, n-propylamine, diethylamine, phenylethylamine, spermidine, benzylamine, trimethylamine, triethylamine, aniline, pyridine, toluene, ethanol, and tetrahydrofuran, respectively. Changes in the emission spectra were recorded and analyzed, and changes in fluorescence color under ultraviolet light irradiation were observed. The results are as follows: Figure 7 As shown. Figure 7In the middle, (a) and (b) are radial histograms, respectively, and the inset is the fluorescence image of the T3 and T4 thin film fluorescence sensor after exposure.

[0211] Depend on Figure 7 It can be seen that the T3 and T4 fluorescent films have high fluorescence intensity ratios for biogenic amine gases, and bright blue and green fluorescence are observed. However, their fluorescence intensity ratios for other amines or other organic interfering substances are very low, indicating that the T3 and T4 fluorescent films have good selectivity for biogenic amine gases.

[0212] Test Example 8

[0213] Anti-interference performance of T3 and T4 thin-film fluorescence sensors in the gas phase detection of biogenic amines:

[0214] Taking cadaverine as an example, the T3 and T4 thin-film fluorescent sensors prepared in Example 13 were first placed in a mixture of toluene, ethanol, and tetrahydrofuran (the volume percentage of tetrahydrofuran in the mixture was 13.6%, the volume percentage of ethanol was 56.6%, the volume percentage of toluene was 20.64%, and the volume percentage of cadaverine was 9.16%), and the changes in their emission spectra were recorded. Then, cadaverine gas (20 μL) was added to the mixture (20 μL), and its emission spectrum was recorded again. The results are as follows. Figure 8 As shown, Figure 8 (a) shows the T3 thin-film fluorescence sensor, and (b) shows the T4 thin-film fluorescence sensor.

[0215] It can be seen that the fluorescence spectra of T3 and T4 only showed a slight enhancement after exposure to a mixture of toluene, ethanol, and tetrahydrofuran. Upon the addition of cadaverine gas, their fluorescence at short wavelengths was significantly quenched, while fluorescence at 480 nm and 520 nm was significantly enhanced. This indicates that the T3 and T4 thin-film fluorescence sensors do not exhibit significant fluorescence response to gases containing other organic solvents, demonstrating excellent anti-interference capabilities.

[0216] Test Example 9

[0217] Repeatability of T3 and T4 thin-film fluorescence sensors in gas-phase detection of biogenic amines:

[0218] Taking cadaverine as an example, the T3 and T4 thin-film fluorescent sensors prepared in Example 13 were placed in cadaverine-saturated gas, and fluorescence spectra were collected. The T3 and T4 fluorescent films were then removed, purged with an air pump for 60 seconds, and fluorescence spectra were collected again. This operation was repeated 15 times, and the ratio I of the fluorescence intensity of the thin-film fluorescent sensors after exposure to cadaverine and after purging was calculated. 470 / I 380 and I 520 / I 410 ,get Figure 9 .

[0219] As shown in the figure, after 15 cycles of fluorescence cycling test, the T3 and T4 fluorescent films still maintained high fluorescence response signals.

[0220] Test Case 10

[0221] Sensitivity of T3 and T4 thin-film fluorescence sensors in gas-phase detection of cadaverine:

[0222] The T3 and T4 thin-film fluorescence sensors prepared in Example 13 were exposed to different concentrations (specifically 0.0125 ppm, 0.025 ppm, 0.05 ppm, 0.1 ppm, 0.2 ppm, 0.38 ppm, 0.75 ppm, 1.5 ppm, 3 ppm, 6 ppm, 12 ppm, 24 ppm, 48 ppm, 96 ppm, 192 ppm, 383 ppm, 765 ppm, and 1330 ppm) of cadaverine gas, and the changes in fluorescence spectra were recorded and analyzed. The results are as follows: Figure 10 As shown. By plotting the fluorescence intensity ratio I... 470 / I 380 and I 520 / I 410 The sensitivity of the T3 and T4 thin-film fluorescence sensors was evaluated by using correlation curves with biogenic amine concentration.

[0223] Depend on Figure 10 It can be seen that the fluorescence intensity ratio I of the T3 and T4 thin-film fluorescence sensors is... 470 / I 380 and I 520 / I 410 It exhibits a good linear relationship in the low concentration range of 0.0125 to 0.1 ppm. When the concentration is higher than 383 ppm, the fluorescence intensity ratio reaches its maximum. According to the fitted curve, the LOD of the T3 and T4 thin film fluorescence sensors is as low as 11 ppb and 14 ppb, respectively.

[0224] Application Example 1

[0225] Standard fluorescent cards prepared from T3 and T4 fluorescent films

[0226] Taking cadaverine as an example, the T3 and T4 fluorescent films prepared in Example 13 were exposed to different concentrations of cadaverine gas. Filter paper strips with clearly distinguishable fluorescent colors were selected as standard fluorescent cards. In this application example, 0 ppm, 1.5 ppm, 3 ppm, 6 ppm, 12 ppm, 24 ppm, 48 ppm, 96 ppm, 192 ppm, and 383 ppm were selected as standard fluorescent cards. Figure 11 As shown, Figure 11(a) shows the T3 thin-film fluorescence sensor, and (b) shows the T4 thin-film fluorescence sensor. By observing the colors of the T3 and T4 standard fluorescence cards—specifically, under 365nm ultraviolet light, the T3 thin-film fluorescence sensor gradually changes from purple fluorescence to blue fluorescence, and the T4 thin-film fluorescence sensor gradually changes from blue fluorescence to green fluorescence—the concentration range of biogenic amines in unknown gases can be directly observed and analyzed with the naked eye. The concentration of biogenic amine vapor can be accurately determined. In other words, the standard fluorescence cards prepared in this invention can accurately distinguish the concentration of biogenic amine vapor at low concentrations with the naked eye, even without large-scale fluorescence testing instruments.

[0227] Application Example 2

[0228] Visual quantitative detection of biogenic amine gas using T3 and T4 fluorescent thin films:

[0229] Taking cadaverine as an example, the T3 and T4 fluorescent films prepared in Example 13 were exposed to cadaverine gas at different concentrations (specifically 1.5 ppm, 3 ppm, 6 ppm, 12 ppm, 24 ppm, 48 ppm, 96 ppm, 192 ppm, and 383 ppm). Fluorescence images of the T3 and T4 film fluorescent sensors under 365 nm ultraviolet light excitation were acquired using a smartphone. Then, the RGB and Lab values ​​were output in real time using color analysis software on the smartphone. ΔE was calculated from the Lab value using the above formula (1).

[0230] Linear fitting was performed with cadaverine gas concentration as the x-axis and ΔE or G value (green channel) as the y-axis to obtain the working curve, as shown below. Figure 12 .

[0231] It can be seen that within the concentration range of 0–12 ppm, the ΔE or G values ​​of the T3 and T4 thin-film fluorescence sensors have a good linear relationship with the concentration of cadaverine gas. The most obvious color change is observed when the concentration reaches 96 ppm, and the color change reaches saturation as the concentration continues to increase. ， By placing the fluorescent film in an unknown gas containing cadaverine, and then using a smartphone to acquire fluorescence images of the film and outputting the G value and / or ΔE of the fluorescence images, the results are substituted into... Figure 12 The standard working curve in the model can be used to obtain the content of cadaverine in an unknown gas.

[0232] In this detection method, the detection limits of the T3 and T4 thin-film fluorescence sensors, calculated from the ΔE-cadherinine concentration working curve, are 0.25 ppm and 0.079 ppm, respectively. The detection limits of both the T3 and T4 thin-film fluorescence sensors, calculated from the G-cadherinine concentration working curve, are 0.9 ppm. This indicates that this method does not require expensive instruments and can effectively eliminate the perceptual errors of human vision regarding color through digital means. It has advantages such as portability, speed, and accuracy.

[0233] Application Example 3

[0234] Visualized quantitative monitoring and evaluation of meat sample freshness using T3 thin-film fluorescence sensor:

[0235] First, meat samples (including shrimp, pork, and beef) weighing between 25±5g were placed in 25mL petri dishes. A T3 thin-film fluorescence sensor was then placed inside the petri dish and stored at 25℃. Fluorescence images were captured every 4 hours for shrimp and every 6 hours for pork and beef. The fluorescence images were then output as Lab values ​​using a smartphone, and ΔE was calculated. Simultaneously, the total volatile basic nitrogen (TVBN) in the meat samples was measured at the same shooting intervals, and a double Y-bar graph of ΔE-TVBN-storage time was plotted. A fitting curve was then constructed with ΔE as the x-axis and TVBN as the y-axis to obtain the desired result. Figure 13 . Figure 13 In the middle, (a) shows the fluorescence images of shrimp, pork, beef, and T3 thin-film fluorescence sensor stored at 25℃ for different times; (b), (c), and (d) are double Y-bar graphs of ΔE-TVBN-storage time of T3 thin-film fluorescence sensor, respectively; and (e) is the linear relationship curve between ΔE and TVBN of T3 thin-film fluorescence sensor.

[0236] from Figure 13 As can be seen in (a), as the storage time increased, the three meat samples gradually decomposed. The T3 fluorescent film also showed a visible change in fluorescence color as the samples decomposed, indicating that the T3 fluorescent film can visually monitor the freshness of meat samples. Figure 13 As can be seen from (b) to (e), there is a good linear relationship between the fluorescence color change of the T3 fluorescent film and the TVBN value. This means that the ΔE value of the corresponding fluorescence image can be output in real time by a smartphone. Substituting this linear relationship into the corresponding TVBN value can be used to quantitatively assess the freshness of meat samples.

[0237] Application Example 4

[0238] Visualized quantitative monitoring and evaluation of the freshness of meat samples using T4 fluorescent film:

[0239] First, meat samples (including shrimp, pork, and beef) weighing between 25±5g were placed in 25mL petri dishes. A T4 thin-film fluorescence sensor was then placed inside the petri dish and stored at 25℃. Fluorescence images were captured every 4 hours for shrimp and every 6 hours for pork and beef. The fluorescence images were then output as Lab values ​​using a smartphone, and ΔE was calculated. Simultaneously, the total volatile basic nitrogen (TVBN) in the meat samples was measured at the same shooting intervals, and a double Y-bar graph of ΔE-TVBN-storage time was plotted. A fitting curve was then constructed with ΔE as the x-axis and TVBN as the y-axis to obtain the desired result. Figure 14 . Figure 14 In the middle, (a) shows the fluorescence images of shrimp, pork, beef, and T4 thin-film fluorescence sensor stored at 25℃ for different times; (b), (c), and (d) are double Y-bar graphs of ΔE-TVBN-storage time of T4 thin-film fluorescence sensor, respectively; and (e) shows the linear relationship between ΔE and TVBN of T4 thin-film fluorescence sensor.

[0240] from Figure 14 As can be seen in (a), as the storage time increased, the three meat samples gradually decomposed. The T4 fluorescent film also showed a visible change in fluorescence color as the samples decomposed, indicating that the T4 fluorescent film can visually monitor the freshness of meat samples. Figure 14 As can be seen from (b) to (e), there is a good linear relationship between the fluorescence color change of the T4 fluorescent film and the TVBN value. This means that the ΔE value of the corresponding fluorescence image can be output in real time by a smartphone. Substituting this linear relationship into the data, the corresponding TVBN value can be obtained, which can be used to quantitatively assess the freshness of meat samples.

[0241] The results above show that the fluorescent films of T3 and T4 can achieve visualized quantitative detection of the freshness of real meat samples, which greatly saves the time required for detection.

[0242] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. Use of a liquid phase fluorescent sensor in the fluorescent detection of a biological amine for non-diagnostic or therapeutic purposes, characterized in that, The liquid-phase fluorescence sensor comprises organic fluorescent molecules and an organic solvent, wherein the organic fluorescent molecules are small organic fluorescent molecule materials, and the small organic fluorescent molecule materials have the structure shown in Formula I: Formula I; In formula I, Z represents Si, O, or S; In formula I, R1 is: , , , , , , , , , or .

2. The application according to claim 1, characterized in that, The organic fluorescent small molecule material has the structure shown in T1, T5, or T6: T1、 T5、 T6.

3. A thin-film fluorescence sensor, comprising a substrate and a fluorescent thin film disposed on the surface of the substrate, wherein the fluorescent thin film is prepared from a parent material, a guest material, and an organic solvent, wherein the guest material is an organic fluorescent small molecule material having the structure shown in Formula I: Equation I; In formula I, Z represents Si, O, or S; In formula I, R1 is: , , , , , , , , , or .

4. The thin-film fluorescence sensor according to claim 3, characterized in that, The organic fluorescent small molecule material has the structure shown in T1, T5, or T6: T1、 T5、 T6.

5. A standard fluorescent card for visual semi-quantitative detection of biogenic amines, characterized in that, It is prepared by the thin-film fluorescent sensor as described in claim 3 or 4.

6. The use of the thin-film fluorescence sensor of claim 3 or 4 or the standard fluorescence card of claim 5 in the detection of biogenic amine fluorescence for non-diagnostic or therapeutic purposes.

7. The application according to claim 6, characterized in that, The biogenic amines include one or more of 1,5-pentanediamine, 1,4-butanediamine, spermine, spermidine, tryptamine, histamine, diethylamine, and triethylamine.

8. The application according to claim 6, characterized in that, The application is the visual quantitative fluorescence detection of biogenic amines, which includes the following steps: performing visual quantitative fluorescence detection of biogenic amines by combining the ΔE value and / or RGB value of the fluorescent card image output in real time by a smartphone.

9. The application according to claim 6, characterized in that, The application is a visual quantitative fluorescence detection of meat sample freshness, which includes the following steps: combining the ΔE value and / or RGB value of the fluorescent card image output in real time by a smartphone to perform visual quantitative fluorescence detection of meat sample freshness.

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