Tanshinone-based conjugate coupling chromogenic molecule as well as preparation method and application thereof

Abstract

The invention provides a tanshinone-based conjugate coupling chromogenic molecule as well as a preparation method and application thereof, and relates to the technical field of analysis and detection of fluid substances. The preparation method of the tanshinone-based conjugate coupling chromogenic molecule comprises the following steps: mixing a tanshinone IIA solution, an organic alkali solution and an isovanillin solution, and carrying out conjugate coupling reaction to obtain the tanshinone-based conjugate coupling chromogenic molecule (HMDTD). HMDTD can present different degrees of rotatable characteristics in different microcell fluid environments and can freely rotate in a low-viscosity liquid object to be detected, the excited state energy is mainly dissipated in a mechanical rotation mode, and a released optical signal is weak; compared with the prior art, rotation in a high-viscosity liquid to-be-measured object is inhibited, excited state energy is mainly dissipated in a radiation transition mode, released optical signals are strong, different optical signal release intensities are presented, and then effective measurement of the viscosity of the micro-area of the liquid to-be-measured object can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of analysis and detection of fluid substances, and particularly to a tanshinone-based conjugated chromogenic molecule, a preparation method thereof, and an application thereof. Background Art

[0002] Vegetable oil is a compound formed by the reaction of higher fatty acids and glycerol, which widely exists in various plants in nature. Its main components include palmitic acid, stearic acid, oleic acid, erucic acid, eleostearic acid, ricinoleic acid, etc., and it contains a large amount of vitamins, calcium, iron, phosphorus, potassium and other components. It is often used as edible oil in human diet (such as soybean oil, rapeseed oil, cottonseed oil, corn oil, peanut oil, etc.), and is also commonly used in industrial vegetable oils in fields such as soap, paint, ink, textile, lubricating oil, synthetic resin, and even cosmetics and medicine. Its application scenarios are very extensive. As a type of high-value-added fluid food, it is commonly found in transparent and flowing liquids, and its viscosity can be controlled by controlling glycerol in the main components, thereby meeting the application needs of different occasions. Vegetable oils with high viscosity are easier to store and shape, and are more significant in terms of richness, but their fluidity is poor, and their wettability and spreading ability are also poor, and their solubility and oil seepage are poor; in contrast, vegetable oils with low viscosity have better fluidity, better spreading and oil seepage, and stronger wetting ability. However, the richness may be poor, and the relative storage and shaping ability is poor. Vegetable oil, as a well-known essential product, many manufacturers have developed various functional vegetable oils for different occasions. In order to more specifically improve the extraction process and refining process of vegetable oil, so as to meet the needs of customers for vegetable oils with different micro-region viscosities, it is imperative to develop a measurement tool that can quickly, in-situ, and visually measure its viscosity. Traditional analysis and testing of vegetable oil viscosity mainly rely on various viscometers, which require a large amount of samples and a long measurement time. More importantly, it is difficult to accurately measure the micro-region viscosity of vegetable oils containing a large amount of pseudoplastic macromolecular components (shear thinning effect exists), and an in-situ, visual, fast and easy measurement method needs to be developed urgently.

[0003] In the field of analysis and detection of fluid foods, photochemical technology can measure the micro-region viscosity of hair gel with the help of molecular tools, and finally show as a visual light signal released. Using this in-situ static response method can effectively avoid the errors caused by traditional shear thinning, and can effectively improve the control effect of the viscosity of fluid foods. Based on this, those skilled in the art urgently need to develop a molecular-level tool suitable for testing the viscosity of fluid foods. Summary of the Invention

[0004] The purpose of the present invention is to provide a tanshinone-based conjugated chromogenic molecule, a preparation method thereof, and an application thereof, so as to solve the problems of high sample volume required by existing methods for viscosity detection and complex detection methods.

[0005] To achieve the above-mentioned invention object, the present invention provides the following technical solutions:

[0006] The present invention provides a tanshinone-based conjugated chromogenic molecule, and its structural formula is shown in Formula I:

[0007]

[0008] The present invention also provides a preparation method of the tanshinone-based conjugated chromogenic molecule, including the following steps:

[0009] Mix the tanshinone IIA solution, the organic base solution and the isovanillin solution to carry out a conjugated coupling reaction to obtain the tanshinone-based conjugated chromogenic molecule.

[0010] Preferably, the concentration of the tanshinone IIA solution is 1-5 mol / L;

[0011] The solvent of the tanshinone IIA solution includes one or more of methanol, acetonitrile, tetrahydrofuran, ethanol, N,N-dimethylformamide, ethyl acetate and dimethyl sulfoxide.

[0012] Preferably, the concentration of the organic base solution is 1-10 mol / L;

[0013] The organic base in the organic base solution includes one or more of triethylamine, trimethylamine, N,N-diisopropylethylamine, pyridine, 4-dimethylaminopyridine, 4-diethylaminopyridine, lithium diisopropylamide, sodium bis(trimethylsilyl)amide, sodium tert-butoxide, potassium tert-butoxide, sodium ethoxide, sodium methoxide, imidazole, N,N,N',N'-tetramethylethylenediamine;

[0014] The solvent of the organic base solution is an alcohol solvent.

[0015] Preferably, the molar ratio of tanshinone IIA in the tanshinone IIA solution to the organic base in the organic base solution is 1:1-10;

[0016] The molar ratio of tanshinone IIA in the tanshinone IIA solution to isovanillin in the isovanillin solution is 1:1-5.

[0017] Preferably, the concentration of the isovanillin solution is 1-8 mol / L;

[0018] The solvent of the isovanillin solution is an alcohol solvent.

[0019] Preferably, the temperature of the conjugated coupling reaction is 60-130 °C, and the time of the conjugated coupling reaction is 1-32 h.

[0020] The present invention also provides an application of the above-mentioned tanshinone-based conjugated chromogenic molecule in viscosity measurement. The application method includes the following steps:

[0021] Mix the tanshinone-based conjugated chromogenic molecule, a solvent, and a substance to be measured to obtain a mixed solution. Detect the intensity of the optical signal released by the mixed solution at 650-850 nm through a fluorescence detection device, and calculate the viscosity of the substance to be measured according to the standard curve of the optical signal intensity and viscosity.

[0022] The dosage ratio of the conjugated chromogenic molecule, the solvent, and the substance to be measured is 1-100 μmol: 1 L: 0.01 L;

[0023] The solvent is castor oil;

[0024] The excitation wavelength of the fluorescence detection device is 530 nm.

[0025] Preferably, the substance to be measured is vegetable oil, and the viscosity range of the substance to be measured is 1.0-956.0 cP;

[0026] The vegetable oil can be selected from one or more of soybean oil, rapeseed oil, cottonseed oil, sunflower oil, tea oil, grape seed oil, jojoba oil, olive oil, sesame oil, rice bran oil, palm oil, corn oil, and peanut oil.

[0027] The present invention has at least the following beneficial effects:

[0028] (1) The tanshinone-based conjugated chromogenic molecule (HMDTD) provided by the present invention is obtained by further conjugating the natural tanshinone extract - tanshinone IIA and a natural fragrance - isovanillin, realizing the effective construction of a large-conjugated organic chromogenic functional molecule. The required raw materials are rich in sources and all belong to natural plant extracts, expanding the application scope of traditional plant extracts in the field of functional molecules, and can be used interdisciplinary for the development of high-value-added molecular tools. The overall application preparation cost is relatively low, and the usage level is in milligrams, and the usage cost is also very low. This way of recombining and conjugating plant extracts is very in line with the concept of low-carbon sustainable development; at the same time, the preparation process is obtained by a one-step method, and the final yield is also relatively high, which can be achieved without going through complicated synthesis steps.

[0029] (2) The tanshinone-based conjugated chromogenic molecule (HMDTD) provided by the present invention exhibits different degrees of rotatable characteristics in different micro-region fluid environments. It can rotate freely in the low-viscosity liquid analyte to be measured, and the dissipation mode of the excited-state energy is mainly through mechanical rotation, releasing weak optical signals. In contrast, in the high-viscosity liquid analyte to be measured, the rotation is inhibited, and the excited-state energy is mainly dissipated through radiative transition, releasing stronger optical signals, showing different intensities of optical signal release. Thus, the effective measurement of the micro-region viscosity of the liquid analyte to be measured can be realized. The specific luminescence principle is as Figure 1 shown, which is related to the mechanical rotation of the molecule. As a molecular-level chromogenic tool, when the tanshinone-based conjugated chromogenic molecule is added to the liquid analyte to be measured, it can exhibit different intensities of optical signal according to the physical viscosity of the micro-region environment it is in. Thus, the thickness of the liquid analyte to be measured can be judged. When the optical signal is stronger, the liquid analyte to be measured is thicker and its fluidity is relatively weaker. In contrast, when the optical signal is weaker, it indicates that the liquid analyte to be measured is thinner, with stronger fluidity and lower viscosity. HMDTD can respond to the change of the micro-region viscosity of the liquid to be measured, which helps to judge the subtle change of its viscosity. It has a high sensitivity to viscosity, with a very high viscosity sensitivity coefficient (x = 0.75). Its chemical structure is relatively stable and can exist in the complex liquid analyte for a long time. Its chromogenic wavelength peak is 678 nm, which is typical red light with bright color and extremely strong visualization effect. In addition, this molecular tool has good tolerance to pH and solvent polarity and can exhibit good photostability during long-term external excitation irradiation. At the same time, this molecular tool has a low detection limit (as low as 1.10 cP), and its sensitivity to viscosity is much greater than the influence of other factors.

[0030] (3) After the tanshinone-based conjugated chromogenic molecule (HMDTD) provided by the present invention is added, it can be used as a molecular tool to measure the micro-region viscosity in situ. During the measurement process, there is no need to use rotational shear to measure viscosity, and the whole process can be detected in a relatively static state. Therefore, it can effectively measure the micro-region viscosity of vegetable oils containing pseudoplastic components. Description of the Drawings

[0031] Figure 1 is the mechanism diagram of the tanshinone-based conjugated chromogenic molecule for measuring the viscosity of vegetable oil;

[0032] Figure 2 is the high-resolution mass spectrum of the tanshinone-based conjugated chromogenic molecule prepared in Example 1;

[0033] Figure 3 is the nuclear magnetic resonance spectrum of the tanshinone-based conjugated chromogenic molecule prepared in Example 1;

[0034] Figure 4Spectral diagram of the tanshinone-based conjugated chromogenic molecule prepared in Example 1 in solutions of different viscosities;

[0035] Figure 5 Linear fitting diagram between the optical signal intensity of the tanshinone-based conjugated chromogenic molecule prepared in Example 1 and the solution viscosity;

[0036] Figure 6 Spectral diagram of the tanshinone-based conjugated chromogenic molecule prepared in Example 1 in solutions of different pH values;

[0037] Figure 7 Results of the photostability test of the tanshinone-based conjugated chromogenic molecule prepared in Example 1 in glycerol and purified water;

[0038] Figure 8 Absorption spectral diagram of the tanshinone-based conjugated chromogenic molecule prepared in Example 1 in different solvents;

[0039] Figure 9 Detection limit diagram of the tanshinone-based conjugated chromogenic molecule prepared in Example 1;

[0040] Figure 10 Emission spectral diagram of the tanshinone-based conjugated chromogenic molecule prepared in Example 1 in different vegetable oils. Detailed implementation mode

[0041] The present invention provides a tanshinone-based conjugated chromogenic molecule, and the structural formula is as shown in Formula I:

[0042]

[0043] The present invention also provides a preparation method of a tanshinone-based conjugated chromogenic molecule, comprising the following steps:

[0044] Mix a tanshinone IIA solution, an organic base solution and an isovanillin solution to carry out a conjugated coupling reaction to obtain a tanshinone-based conjugated chromogenic molecule.

[0045] In the present invention, the concentration of the tanshinone IIA solution is 1-5 mol / L, preferably 2-4 mol / L, and further preferably 2-3 mol / L.

[0046] In the present invention, the solvent of the tanshinone IIA solution includes one or more of methanol, acetonitrile, tetrahydrofuran, ethanol, N,N-dimethylformamide, ethyl acetate and dimethyl sulfoxide.

[0047] In the present invention, the concentration of the organic base solution is 1-10 mol / L, preferably 2-8 mol / L, further preferably 4-6 mol / L, and more preferably 5 mol / L.

[0048] In the present invention, the organic base in the organic base solution includes one or more of triethylamine, trimethylamine, N,N-diisopropylethylamine, pyridine, 4-dimethylaminopyridine, 4-diethylaminopyridine, lithium diisopropylamide, sodium bis(trimethylsilyl)amide, sodium tert-butoxide, potassium tert-butoxide, sodium ethoxide, sodium methoxide, imidazole, and N,N,N',N'-tetramethylethylenediamine.

[0049] In the present invention, the solvent of the organic base solution is an alcohol solvent.

[0050] In the present invention, the molar ratio of tanshinone IIA in the tanshinone IIA solution to the organic base in the organic base solution is 1:1 to 10, preferably 1:2 to 8, more preferably 1:3 to 6, and even more preferably 1:4 to 5.

[0051] In the present invention, the molar ratio of tanshinone IIA in the tanshinone IIA solution to isovanillin in the isovanillin solution is 1:1 to 5, preferably 1:2 to 4, more preferably 1:3 to 4.

[0052] In the present invention, the concentration of the isovanillin solution is 1 to 8 mol / L, preferably 2 to 7 mol / L, more preferably 3 to 6 mol / L, and even more preferably 4 to 5 mol / L.

[0053] In the present invention, the solvent of the isovanillin solution is an alcohol solvent.

[0054] In the present invention, the temperature of the conjugate coupling reaction is 60 to 130 °C, preferably 70 to 120 °C, more preferably 80 to 110 °C, and even more preferably 90 to 100 °C; the time of the conjugate coupling reaction is 1 to 32 h, preferably 5 to 25 h, more preferably 10 to 20 h, and even more preferably 15 to 18 h.

[0055] The structure of the tanshinone IIA is shown in Formula II:

[0056]

[0057] In the present invention, the conjugate coupling reaction further includes a step of separating and purifying the tanshinone-based conjugate coupling chromogenic molecule, and the specific operation method is as follows:

[0058] 1. Extraction: The solvent of the reaction product is removed at -0.09 MPa, and then extracted with a mixed solution of ethyl acetate and water. The organic phase is collected and the solvent is removed under reduced pressure to -0.09 MPa.

[0059] 2. Purification: Dissolve the extracted product in a mixed solution of dichloromethane and methanol, and purify it using chromatographic grade silica gel powder (200 - 1000 mesh).

[0060] 3. Crystallization: Redisperse the purified product in a mixed solution of ethanol and purified water, and let it stand to precipitate crystalline powder.

[0061] 4. Centrifugation: Disperse the crystalline powder obtained from crystallization in a mixed solution of ethanol and purified water, control the solid content to be 10 - 50 mg / mL, and then perform centrifugation, repeating the operation 1 - 4 times.

[0062] 5. Drying: Place the centrifuged product in a freeze dryer for drying to obtain the tanshinone - based conjugated chromogenic molecule product.

[0063] In the present invention, during the extraction process, the volume ratio of ethyl acetate to water is preferably 1 - 15:1, more preferably 2 - 10:1, and even more preferably 3 - 5:1.

[0064] In the present invention, during the purification process, the volume ratio of dichloromethane to methanol is preferably 1 - 50:1, preferably 5 - 40:1, more preferably 10 - 30:1, and even more preferably 15 - 20:1.

[0065] In the present invention, during the crystallization process, the volume ratio of ethanol to purified water is preferably 1:1 - 30, more preferably 1:5 - 25, and even more preferably 1:10 - 20; the standing temperature is 1 - 10°C, preferably 3 - 8°C, and even more preferably 5 - 6°C; the standing time is 1 - 20 h, preferably 3 - 18 h, more preferably 5 - 15 h, and even more preferably 8 - 12 h.

[0066] In the present invention, during the centrifugation process, the volume ratio of ethanol to purified water is preferably 1:1 - 50, more preferably 1:5 - 40, and even more preferably 1:10 - 30; the centrifugation speed is preferably 1000 - 10000 r / min, more preferably 3000 - 8000 r / min, and even more preferably 5000 - 6000 r / min; the centrifugation time is preferably 6 - 60 min, more preferably 10 - 50 min, and even more preferably 20 - 40 min.

[0067] In the present invention, during the drying process, the drying temperature is preferably - 30 - - 5°C, more preferably - 25 - - 10°C, and even more preferably - 20 - - 15°C; the drying time is preferably 1 - 48 h, more preferably 3 - 40 h, and even more preferably 5 - 36 h.

[0068] The present invention also provides an application of the above - mentioned tanshinone - based conjugated chromogenic molecule in viscosity measurement. The application method includes the following steps:

[0069] Mix the tanshinone-based conjugated chromogenic molecule, solvent and the substance to be measured to obtain a mixed solution, and detect the intensity of the optical signal released by the mixed solution at 650-850 nm through a fluorescence detection device. Calculate the viscosity of the substance to be measured according to the standard curve of the optical signal intensity and viscosity.

[0070] In the present invention, the dosage ratio of the conjugated chromogenic molecule, solvent and the substance to be measured is 1-100 μmol: 1 L: 0.01 L, further preferably 5-90 μmol: 1 L: 0.01 L, and more preferably 10-80 μmol: 1 L: 0.01 L.

[0071] In the present invention, the solvent is castor oil.

[0072] In the present invention, the excitation wavelength of the fluorescence detection device is 530 nm.

[0073] In the present invention, the substance to be measured is vegetable oil, and the viscosity range of the substance to be measured is 1.0-956.0 cP.

[0074] In the present invention, the vegetable oil can be selected from one or more of soybean oil, rapeseed oil, cottonseed oil, sunflower oil, tea oil, grape seed oil, jojoba oil, olive oil, sesame oil, rice bran oil, palm oil, corn oil and peanut oil.

[0075] The tanshinone-based conjugated chromogenic molecule (HMDTD) provided by the present invention will exhibit different degrees of rotatable characteristics in different micro-region fluid environments. It can rotate freely in the liquid substance to be measured with low viscosity, and the dissipation mode of the excited state energy is mainly through mechanical rotation, and the released optical signal is weak. In contrast, the rotation is inhibited in the liquid substance to be measured with high viscosity, and the excited state energy is mainly dissipated through radiative transition, and the released optical signal is strong, showing different optical signal release intensities, and thus the effective measurement of the micro-region viscosity of the liquid substance to be measured can be realized. The specific luminescence principle is as Figure 1 shown and is related to the mechanical rotation of the molecule.

[0076] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0077] Example 1

[0078] Dissolve 294.34 g (1 mol) of tanshinone IIA in acetonitrile, stir evenly at room temperature (25 °C) to obtain a tanshinone IIA solution with a concentration of 2 mol / L;

[0079] Dissolve 295.55 g (5 mol) of trimethylamine organic base in ethanol and stir evenly at room temperature (25 °C) to obtain a 5 M trimethylamine organic base solution;

[0080] Dissolve 304.30 g (2 mol) of isovanillin solution in methanol and stir evenly at room temperature (25 °C) to obtain a 2 mol / L sodium carbonate dehydrating agent dispersion;

[0081] First, mix the tanshinone IIA solution and the organic base solution at room temperature (25 °C) and stir at a rate of 500 rpm for 6.0 h. Then, while maintaining the stirring rate, add the isovanillin solution dropwise to the aforementioned mixture at a rate of 5 mL / min during the heating process. The heating rate is 5 °C / h until the target temperature of 70 °C is reached. Then, carry out a conjugate coupling reaction at a stirring rate of 1600 rpm. After reacting for 16 h, a reaction solution containing tanshinone-based conjugate-coupled chromogenic molecules is obtained.

[0082] The obtained reaction solution containing tanshinone-based conjugate-coupled chromogenic molecules is successively subjected to extraction, purification, crystallization, centrifugation, and drying. The specific operation steps are as follows:

[0083] After removing the solvent from the reaction solution containing tanshinone-based conjugate-coupled chromogenic molecules under -0.09 MPa, extract it with a mixed solution of ethyl acetate and purified water with a volume ratio of 10:1. Collect the organic phase and then reduce the pressure to -0.09 MPa to remove the solvent to obtain a crude product; dissolve the crude product in a mixed solution of dichloromethane and methanol, control the volume ratio of dichloromethane to methanol to be 30:1, and purify it using chromatographic grade silica gel powder (500 mesh); redisperse the purified product in a mixed solution of ethanol and purified water, control the solid content of the solution to be 15 mg / 10 mL, and the volume ratio of ethanol to purified water to be 1:15, and place it at a low temperature of 5 °C and let it stand for 10 h to precipitate crystalline powder; disperse the crystalline powder in a mixed solution of ethanol and purified water, the volume ratio of ethanol to purified water is 1:30, and control the solid content to be 30 mg / mL, and then centrifuge at a speed of 5000 r / min for 30 min, and repeat the operations of dissolution and centrifugation 2 times; place the centrifuged product in a freeze-drying oven and dry it at -15 °C for 24 h to obtain tanshinone-based conjugate-coupled chromogenic molecules, denoted as HMDTD, with a yield of 39.0 g and a yield rate of 91.1%.

[0084] Perform mass spectrometry analysis on the relative molecular mass of the tanshinone-based conjugate-coupled chromogenic molecule HMDTD prepared above. The results are as Figure 2 shown. From Figure 2 it can be seen that the relative molecular mass of the tanshinone-based conjugate-coupled chromogenic molecule HMDTD is 428.46168 [M] + , and the molecular formula of Formula 1 is C 27 H24 O 5 , its theoretically estimated relative mass is 428.48. In terms of relative molecular mass, it can be found that the product obtained in Example 1 is consistent with the target product. At the same time, the chemical structure of the obtained product was tested, and the carbon-13 nuclear magnetic resonance spectrum is as Figure 3 shown. From Figure 3 it can be seen that 13 C NMR (101 MHz, DMSO-d 6 ) δ 182.01, 178.51, 161.30, 149.45, 148.22, 145.42, 143.61, 140.50, 135.10, 131.10, 129.79, 128.43, 127.90, 127.51, 123.02, 118.30, 116.92, 114.21, 111.91, 57.80, 36.30, 33.92, 31.12, 27.53, 18.32. The chemical shifts of the carbon skeleton in its molecular structure are confirmed, and it can be determined that it is the target product tanshinone-based conjugated chromogenic molecule HMDTD.

[0085] Example 2

[0086] Dissolve 294.34 g (1 mol) of tanshinone IIA in tetrahydrofuran and stir evenly at room temperature (25 °C) to obtain a tanshinone IIA solution with a concentration of 1 mol / L;

[0087] Dissolve 101.19 g (1 mol) of triethylamine organic base in methanol and stir evenly at room temperature (25 °C) to obtain a triethylamine organic base solution with a concentration of 1 mol / L;

[0088] Dissolve 152.15 g (1 mol) of isovanillin solution in ethanol and stir evenly at room temperature (25 °C) to obtain a sodium carbonate dehydrating agent dispersion with a concentration of 1 mol / L;

[0089] First, mix the tanshinone IIA solution and the organic base solution at room temperature (25 °C) and stir at a rate of 100 rpm for 12.0 h. Then, while keeping the stirring rate unchanged, add the isovanillin solution dropwise to the aforementioned mixture at a rate of 1 mL / min during the heating process. The heating rate is 15 °C / h until the target temperature of 60 °C is reached. Then, carry out a conjugate coupling reaction at a stirring rate of 1000 rpm. After reacting for 32 h, a reaction solution containing tanshinone-based conjugated chromogenic molecules is obtained.

[0090] The obtained reaction solution containing tanshinone-based conjugated chromogenic molecules is successively subjected to extraction, purification, crystallization, centrifugation, and drying. The specific operation steps are as follows:

[0091] After removing the solvent from the reaction solution containing the tanshinone-based conjugated chromogenic molecule under -0.09 MPa, extraction was carried out using a mixed solution of ethyl acetate and purified water with a volume ratio of 1:1. The organic phase was collected and then the solvent was removed under reduced pressure to -0.09 MPa to obtain the crude product. The crude product was dissolved in a mixed solution of dichloromethane and methanol, with the volume ratio of dichloromethane to methanol controlled at 1:1, and purified using chromatographic grade silica gel powder (200 mesh). The purified product was redispersed in a mixed solution of ethanol and purified water, with the solid content of the solution controlled at 1 mg / 10 mL and the volume ratio of ethanol to purified water at 1:1, and left to stand at a low temperature of 1 °C for 1.0 h to precipitate crystalline powder. The crystalline powder was dispersed in a mixed solution of ethanol and purified water, with the volume ratio of ethanol to purified water at 1:1 and the solid content controlled at 10 mg / mL, and then centrifuged at a speed of 1000 r / min for 60 min. The operations of dissolution and centrifugation were repeated 4 times. The centrifuged product was placed in a freeze-drying oven and dried at -30 °C for 1 h to obtain the tanshinone-based conjugated chromogenic molecule, denoted as HMDTD, with a yield of 3.56 g and a yield rate of 83.1%.

[0092] The high-resolution mass spectrometry results and nuclear magnetic resonance spectra of the tanshinone-based conjugated chromogenic molecule HMDTD prepared in this example are consistent with those obtained in Example 1.

[0093] Example 3

[0094] Dissolve 294.34 g (1 mol) of tanshinone derivative in N,N-dimethylformamide and stir evenly at room temperature (25 °C) to obtain a tanshinone derivative solution with a concentration of 5 mol / L.

[0095] Dissolve 1292.4 g (10 mol) of N,N-diisopropylethylamine organic base in propanol and stir evenly at room temperature (25 °C) to obtain a triethylamine organic base solution with a concentration of 10 mol / L.

[0096] Dissolve 760.75 g (5 mol) of isovanillin solution in propanol and stir evenly at room temperature (25 °C) to obtain a sodium carbonate dehydrating agent dispersion with a concentration of 5 mol / L.

[0097] First, mix the tanshinone derivative solution and the organic base solution at room temperature (25 °C) and stir at a rate of 1000 rpm for 0.5 h. Then, while maintaining the stirring rate, add the isovanillin solution dropwise to the aforementioned mixture during the heating process at a speed of 10 mL / min, with a heating rate of 1 °C / min until the target temperature of 130 °C is reached. Then, carry out the conjugate coupling reaction at a stirring rate of 2200 rpm. After reacting for 1 h, a reaction solution containing the tanshinone-based conjugated chromogenic molecule is obtained.

[0098] The obtained reaction solution containing the tanshinone-based conjugated chromogenic molecule was successively subjected to extraction, purification, crystallization, centrifugation, and drying. The specific operation steps are as follows:

[0099] After removing the solvent from the reaction solution containing the tanshinone-based conjugated chromogenic molecule at -0.09 MPa, extraction was carried out using a mixed solution of ethyl acetate and purified water with a volume ratio of 15:1. The organic phase was collected and then the solvent was removed under reduced pressure to -0.09 MPa to obtain a crude product. The crude product was dissolved in a mixed solution of dichloromethane and methanol, with the volume ratio of dichloromethane to methanol controlled at 50:1, and purification was carried out using chromatographic grade silica gel powder (1000 mesh). The purified product was redispersed in a mixed solution of ethanol and purified water, with the solid content of the solution controlled at 30 mg / 10 mL and the volume ratio of ethanol to purified water at 1:30, and it was left to stand at a low temperature of 10 °C for 20 h to precipitate crystalline powder. The crystalline powder was dispersed in a mixed solution of ethanol and purified water, with the volume ratio of ethanol to purified water at 1:30 and the solid content controlled at 50 mg / mL, and then centrifuged at a speed of 10000 r / min for 10 min. The centrifuged product was placed in a freeze-drying oven and dried at -5 °C for 48 h to obtain the tanshinone-based conjugated chromogenic molecule, denoted as HMDTD, with a yield of 7.3 g and a yield rate of 85.2%.

[0100] The high-resolution mass spectrometry results and nuclear magnetic resonance spectra of the tanshinone-based conjugated chromogenic molecule HMDTD prepared in this example were consistent with those obtained in Example 1.

[0101] Performance Test

[0102] A variety of spectroscopic tests were carried out on the tanshinone-based conjugated chromogenic molecule HMDTD prepared in Example 1, including: viscosity sensitivity test, photostability test, pH stability test, solvent tolerance, and detection limit test.

[0103] 1. Viscosity sensitivity test of the tanshinone-based conjugated chromogenic molecule HMDTD prepared in Example 1:

[0104] Solutions with different viscosities (1.0 cP - 956.0 cP) were prepared by mixing glycerol and purified water in different proportions (the corresponding relationship between the viscosity of the solution and the glycerol content in the solution is shown in Table 1). The solution of the tanshinone-based conjugated chromogenic molecule HMDTD (with castor oil as the solvent) was added respectively so that the concentration of HMDTD was 10 μM. The external excitation wavelength was controlled at 530 nm and the test was carried out at room temperature. The obtained spectrogram is as Figure 4 shown.

[0105] Table 1 Corresponding relationship between the viscosity of the solution and the glycerol content in the solution

[0106]

[0107] It can be seen that as the solution viscosity increases from 1.0 cP to 956.0 cP, the intensity of the observable optical signal gradually increases. Especially when the addition amount of glycerol exceeds 50%, the intensity of the released optical signal increases sharply. When in glycerol, the optical signal intensity reaches the maximum value, which is 168 times higher than that of the solution system with a glycerol volume fraction of 0% (purified water system). Figure 4 Figure 4

[0108] In addition, the relationship between the optical signal intensity and the solution viscosity was established. The range of the solution viscosity was 1.00 - 956.00 cP. After converting the optical signal intensity and the solution viscosity into logarithmic functions, they were fitted into a straight line, which conforms to the relational expression, specifically as Figure 5 shown, and the specific logarithmic function values are shown in Table 2.

[0109] Table 2 Logarithm of solution viscosity and logarithm of fluorescence intensity

[0110]

[0111] It can be seen from Figure 5 and Table 2 that the viscosity sensitivity coefficient of HMDTD is 0.75, and the fitting determination coefficient is 0.97, indicating a high sensitivity to viscosity. The results show that the tanshinone - based conjugated chromogenic molecule HMDTD provided by the present invention can be used as a molecular tool for measuring the viscosity of plant oil microdomains, and the thickness can be judged by the strength of the presented apparent optical signal, providing data support and solutions for the optimization of its fast, efficient and visual extraction process.

[0112] 2. pH stability test of the tanshinone - based conjugated chromogenic molecule HMDTD prepared in Example 1:

[0113] Dissolve 1.29 mg of the tanshinone - based conjugated chromogenic molecule HMDTD prepared in Example 1 in castor oil, with the concentration of HMDTD being 3 mM. Add it to buffer solutions with pH values ranging from 3.0 to 12.0 such that the concentration of HMDTD is 10 μM, and test the change in the optical signal intensity at room temperature. The test results are as Figure 6 shown.

[0114] It can be seen from Figure 6 that the fluorescence intensity of the tanshinone - based conjugated chromogenic molecule HMDTD shows a weak fluorescence signal release intensity within the range of pH = 3.0 - 12.0, showing good optical signal release stability, indicating that this conjugated chromogenic molecule can have good optical signal release performance in different pH environments and is not easily interfered with.

[0115] 3. Photostability Test of the Tanshinone-based Conjugated Chromogenic Molecule HMDTD Prepared in Example 1:

[0116] Dissolve 2.57 mg of the tanshinone-based conjugated chromogenic molecule HMDTD prepared in Example 1 in castor oil, with the concentration of HMDTD being 6 mM. Then add it to low-viscosity purified water (1.0 cP) and high-viscosity 90% (by volume) glycerol solution (956.0 cP) respectively to make the concentration of HMDTD 10 μM. Under continuous irradiation of an external excitation light source at 530 nm, test the change of its optical signal intensity within 60 min. The test results are as Figure 7 shown, and the obtained data are shown in Table 3.

[0117] Table 3 Fluorescence Test Results

[0118]

[0119] From Figure 7 the data obtained in Table 3, it can be seen that the tanshinone-based conjugated chromogenic molecule HMDTD can maintain good photostability whether in high-viscosity glycerol or low-viscosity purified water, and will not be greatly affected even under long-term irradiation.

[0120] 4. Polarity Tolerance Test of the Tanshinone-based Conjugated Chromogenic Molecule HMDTD Prepared in Example 1:

[0121] Dissolve 3.43 mg of the tanshinone-based conjugated chromogenic molecule HMDTD prepared in Example 1 in ethanol, with the concentration of HMDTD being 8 mM. Then add it to a variety of conventional solvents with different polarities to make the concentration of HMDTD 10 μM, and test the light signal absorption law under the atmosphere of different polar solvents. The above test is carried out at room temperature, and the results are as Figure 8 shown.

[0122] From Figure 8 the obtained results, it can be seen that in a variety of solvents with different polarities (including glycerol, methanol, tetrahydrofuran, ethyl acetate, dimethyl sulfoxide, toluene), the absorbance of the tanshinone-based conjugated chromogenic molecule HMDTD is all around 0.48, and the peak of its absorption spectrum is all around 530 nm. The overall results show that the molecular tool HMDTD is not sensitive to the polarity of the solution and is suitable for use in vegetable oils containing a variety of polar components.

[0123] 5. Detection Limit of the Tanshinone-based Conjugated Chromogenic Molecule HMDTD Prepared in Example 1:

[0124] Dissolve 0.86 mg of the tanshinone-based conjugated chromogenic molecule HMDTD prepared in Example 1 in castor oil to control an HMDTD solution with a concentration of 2 mmol / L. When testing, dilute the concentration to 10 μmol / L and add it to a mixed solution of water and glycerol with extremely low viscosity respectively to test its detection sensitivity to viscosity. The above test is carried out at room temperature to obtain the linear fitting diagram of the detection limit of HMDTD obtained in Example 1, as shown in Figure 9 shown (I 678 refers to the luminescence intensity I value corresponding to a wavelength of 678 nm). It can be seen from Figure 9 that in a solution with extremely low viscosity, there is a good linear relationship between the viscosity value of HMDTD and the logarithm of the light signal release intensity (y = 1.75 + 1.42x), and the fitting coefficient of determination is 0.99. Through this linear relationship, the detection limit of HMDTD is 1.10 cP, indicating that it is very sensitive to the change of micro-region viscosity and is suitable for regulating and monitoring the change of the consistency of vegetable oils.

[0125] Application Example 1

[0126] Dissolve 2.14 mg of the tanshinone-based conjugated chromogenic molecule HMDTD prepared in Example 1 in ethanol to obtain an HMDTD solution with a concentration of 5 mmol / L, and then add it to Vegetable Oil 1, Vegetable Oil 2, and Vegetable Oil 3 respectively, where the concentration of HMDTD is 10 μmol / L; then at room temperature, conduct emission spectrum tests on the above addition of HMDTD to the above three different vegetable oils respectively, with an external excitation light source of 530 nm, and the obtained emission spectrum diagrams are as shown in Figure 10 shown, and the light signal intensities and viscosities of different mixed solutions are shown in Table 4.

[0127] Table 4 Light Signal Intensities and Viscosities of Different Vegetable Oils

[0128] specimen optical signal intensity viscosity viscosity (viscometer) vegetable oil 1 354.8 8.51 cP 8.62 cP vegetable oil 2 467.7 12.11 cP 12.40 cP vegetable oil 3 524.8 15.13 cP 15.54 cP

[0129] From Figure 8From the data in Table 4, it can be seen that there are significant differences in the viscosities of the three vegetable oils, which in turn lead to significant differences in the intensity of the optical signals. Specifically, the optical signal intensity of Vegetable Oil 1 (soybean oil) is the lowest, indicating that its consistency is relatively thin. The test data shows that its viscosity is 8.51 cP. The optical signal of Vegetable Oil 2 (sesame oil) has a medium intensity, indicating that its consistency has increased to a certain extent and is of medium consistency overall. The test data shows that its viscosity is 12.11 cP. The optical signal intensity of Vegetable Oil 3 (rapeseed oil) further increases, and its overall consistency is relatively high. The test data shows that its viscosity is 15.13 cP. It can be seen that the tanshinone-based conjugated chromogenic molecule HMDTD provided by the present invention can exhibit optical signals of different intensities for vegetable oils with different consistencies. Its peak emission wavelength is 678 nm, which is bright red light and has a visual monitoring effect, which is very similar to the results measured by a traditional viscometer, indicating its high reliability.

[0130] As can be seen from the above examples, the present invention provides a tanshinone-based conjugated chromogenic molecule and its preparation method and application. The tanshinone derivative of the present invention is extracted from natural salvia miltiorrhiza and further conjugated with another spice, isovanillin, to obtain the tanshinone-based conjugated chromogenic molecule (HMDTD) through a one-step method. The tanshinone-based conjugated chromogenic molecule (HMDTD) provided by the present invention has an alternating single and double bond conjugated structure and can exhibit different rotational states in solution atmospheres with different viscosities, and then convert them into optical signals and release them, realizing the rapid, efficient, and visual detection of the viscosity (consistency) of the micro-region of vegetable oils. It is particularly suitable for detecting the consistency of vegetable oils containing a large amount of pseudoplastic components, can complete the measurement without going through a rotational shearing process, and can be intuitively presented in situ through the intensity of the apparent optical signal. Various test results show that the tanshinone-based conjugated chromogenic molecule (HMDTD) has a high sensitivity coefficient (x = 0.75), good pH stability, and excellent light stability. In addition, the tanshinone-based conjugated chromogenic molecule (HMDTD) has strong tolerance to solvents with different polarities, is suitable for real-time response to the viscosity of the micro-region of vegetable oils, and also has a low detection limit (as low as 1.10 cP). Moreover, the preparation process of the tanshinone-based conjugated chromogenic molecule (HMDTD) is simple and easy to operate, environmentally friendly, and has a high final yield. The raw materials are derived from natural products, are rich and have high added value, and the use cost is very low, making it suitable for large-scale industrial production applications.

[0131] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A tanshinone-based conjugated chromogenic molecule, characterized in that: The structural formula is shown in Formula I:

2. The method for preparing a tanshinone-based conjugated chromogenic molecule according to claim 1, characterized in that: The following steps are involved: The tanshinone IIA solution, the organic base solution and the isovanillin solution are mixed to carry out a conjugated coupling reaction to obtain a tanshinone-based conjugated coupling chromogenic molecule.

3. The method for preparing a tanshinone-based conjugated chromogenic molecule according to claim 2, characterized in that: The concentration of the Tanshinone IIA solution is 1 to 5 mol / L; The solvent of the Tanshinone IIA solution includes one or more of methanol, acetonitrile, tetrahydrofuran, ethanol, N,N-dimethylformamide, ethyl acetate and dimethyl sulfoxide.

4. The method for preparing a tanshinone-based conjugated chromogenic molecule according to claim 3, characterized in that: The concentration of the organic alkali solution is 1 to 10 mol / L; The organic base in the organic base solution includes one or more of triethylamine, trimethylamine, N,N-diisopropylethylamine, pyridine, 4-dimethylaminopyridine, 4-diethylaminopyridine, lithium diisopropylamide, sodium bis(trimethylsilyl)amide, sodium tert-butoxide, potassium tert-butoxide, sodium ethoxide, sodium methoxide, imidazole, and N,N,N',N'-tetramethylethylenediamine; The solvent of the organic alkali solution is an alcohol solvent.

5. The method for preparing a tanshinone-based conjugated chromogenic molecule according to any one of claims 2 to 4, characterized in that: The molar ratio of tanshinone IIA in the tanshinone IIA solution to the organic base in the organic base solution is 1:1-10; The molar ratio of tanshinone IIA in the tanshinone IIA solution to isovanillin in the isovanillin solution is 1:1-5.

6. The method for preparing a tanshinone-based conjugated chromogenic molecule according to claim 5, characterized in that: The concentration of the isovanillin solution is 1 to 8 mol / L; The solvent of the isovanillin solution is an alcohol solvent.

7. The method for preparing a tanshinone-based conjugated chromogenic molecule according to claim 6, characterized in that: The temperature of the conjugation coupling reaction is 60-130° C., and the time of the conjugation coupling reaction is 1-32 hours.

8. The use of a tanshinone-based conjugated chromogenic molecule according to claim 1 in viscosity measurement, characterized in that: The application method comprises the following steps: The tanshinone-based conjugated chromogenic molecule, solvent and the substance to be tested are mixed to obtain a mixed solution, the intensity of the light signal released by the mixed solution at 650-850nm is detected by a fluorescence detection device, and the viscosity of the substance to be tested is calculated based on a standard curve of light signal intensity and viscosity.

9. The use of a tanshinone-based conjugated chromogenic molecule in viscosity measurement according to claim 8, characterized in that: The usage ratio of the conjugated chromogenic molecule, the solvent and the substance to be tested is 1-100 μmol: 1L: 0.01L; The solvent is castor oil; The excitation wavelength of the fluorescence detection device is 530 nm.

10. The use of a tanshinone-based conjugated chromogenic molecule in the measurement of vegetable oil viscosity according to claim 9, characterized in that: The substance to be tested is vegetable oil, and the viscosity range of the substance to be tested is 1.0 to 956.0 cP; The vegetable oil can be selected from one or more of soybean oil, rapeseed oil, cottonseed oil, sunflower seed oil, tea oil, grape seed oil, jojoba oil, olive oil, sesame oil, rice oil, palm oil, corn oil and peanut oil.

Images