A water-soluble fluorescent probe, a synthesis method thereof and a use thereof for detecting plasticizers

Abstract

The application belongs to the technical field of chemical analysis and detection, and discloses a water-soluble fluorescent probe, a synthesis method thereof and a use for detecting plasticizers. The modified andrographolide can simultaneously act as a hydrogen bond acceptor and a hydrogen bond donor, and is assembled with fluoroboropyrroles, and a hydroxyl fluoroboropyrrole is taken as a typical one for assembly, so that the andrographolide derivative complex can selectively recognize phthalate esters in a water system. The BODIPY and andrographolide derivative complex has no fluorescence after being assembled with PEG. After phthalate esters are added, the fluorescence is turned on due to the strong hydrophobic effect of the phthalate esters, so that the andrographolide derivative complex can be used for detecting phthalate esters. The detection method has the advantages of non-toxicity, high sensitivity, high accuracy and efficiency, real-time and visual detection, etc.

Description

Technical Field

[0001] This invention belongs to the field of chemical analysis and detection technology, and relates to a water-soluble fluorescent probe, its synthesis method, and its use in detecting the plasticizer phthalate. Background Technology

[0002] Phthalates, as plasticizers, are widely added to food packaging, children's toys, and polyvinyl chloride (PVC) plastics. Long-term exposure can damage the reproductive and nervous systems. Phthalates are ubiquitous in daily life; these compounds are poorly soluble in water and do not volatilize at room temperature. Therefore, developing new, highly sensitive, accurate, efficient, non-toxic, and visual methods for detecting phthalates is of great significance in reducing the probability of poisoning. BODIPY, due to its high quantum yield and ease of modification, has been used as a fluorescent probe for detecting pollutants in the environment and organisms. Summary of the Invention

[0003] The purpose of this invention is to provide a water-soluble fluorescent probe and its synthesis method, and to apply it to the detection of phthalate plasticizers. This invention uses modified andrographolide, which can simultaneously act as both an acceptor and donor for hydrogen bonds, and assembles it with fluoroboronpyrroles, using hydroxyfluoroboronpyrrole as a typical example. In an aqueous system, it can selectively recognize phthalates. The BODIPY and andrographolide derivative complex, after assembly with PEG, exhibits no fluorescence. Upon addition of phthalates, fluorescence is activated due to the strong hydrophobic effect of phthalates.

[0004] A water-soluble fluorescent probe is obtained by assembling modified andrographolide (N-Andro) and fluoroboropyrrole (BODIPY).

[0005] A method for synthesizing a water-soluble fluorescent probe includes the following steps: dissolving fluoroboron pyrrole (BODIPY) in tetrahydrofuran, adding solid andrographolide (N-Andro), adding polyethylene glycol (PEG) aqueous solution, stirring thoroughly, concentrating under reduced pressure, and centrifuging to obtain the target product, a water-soluble fluorescent probe.

[0006] The molar ratio of BODIPY to N-Andro is 1:0.5-1, and the stirring time is 2-3 hours.

[0007] Preferably, the fluoroboropyrrole is hydroxyfluoroboropyrrole, and the molar ratio of hydroxyfluoroboropyrrole to N-Andro is 1:0.7;

[0008] The volume ratio of the tetrahydrofuran to the PEG aqueous solution is 1:0.5-2;

[0009] Preferably, the volume ratio of tetrahydrofuran to the PEG aqueous solution is 1:1.

[0010] The degree of polymerization of polyethylene glycol (PEG) is 1000-10000, preferably 5000.

[0011] The synthetic route for one of the raw materials, fluoroboropyrrole (BODIPY), is as follows:

[0012]

[0013] R is an alkyl group, a hydroxyl group, or a halogen;

[0014] Furthermore, when R is a hydroxyl group, the typical hydroxyfluoroboronpyrrole (OH-BODIPY) synthesis method involves using p-hydroxybenzaldehyde and 2,4-dimethylpyrrole as starting materials, concentrating them in the presence of trifluoroacetic acid, DDQ, triethylamine, and boron trifluoride diethyl ether, followed by silica gel column chromatography to obtain hydroxyfluoroboronpyrrole (OH-BODIPY). The synthetic route is as follows:

[0015]

[0016] The method for synthesizing the modified andrographolide from the second raw material includes the following steps:

[0017] (1) Disperse andrographolide in a chloroform solution of p-nitrobenzaldehyde, add a catalyst amount of p-toluenesulfonic acid, and allow it to react fully;

[0018] (2) After the reaction is complete, add anhydrous Na2CO3 to the mixture in step (1) and stir thoroughly at room temperature for 2-3 hours;

[0019] (3) The reaction solution obtained in step (2) is concentrated under reduced pressure to remove chloroform, redissolved with dichloromethane, washed with deionized water, and extracted.

[0020] (4) The organic phase obtained in step (3) is dried with anhydrous Na2SO4, filtered, and concentrated under reduced pressure.

[0021] (5) Dissolve the sample from step (4) completely with dichloromethane, add petroleum ether while hot, let stand, remove the lower precipitate, and repeat the process of adding dichloromethane and petroleum ether 3-4 times to obtain a milky white solid N-Andro. The synthetic route of N-Andro is shown in the following formula:

[0022]

[0023] In step (1), the molar ratio of andrographolide, p-nitrobenzaldehyde and p-toluenesulfonic acid is 1:1:0.1-0.3, and the reaction conditions are heating and reflux at 60°C for 4-5 hours.

[0024] In step (2), the molar ratio of p-toluenesulfonic acid and anhydrous Na2CO3 is 1:1.

[0025] In step (5), the volume ratio of petroleum ether to dichloromethane is 3:1, and the reaction conditions are heating at 50°C under reflux for 1.5 hours.

[0026] The water-soluble fluorescent probe prepared according to this invention is used for detecting plasticizers.

[0027] Furthermore, the water-soluble fluorescent probe is used for the detection of phthalates.

[0028] Furthermore, the water-soluble fluorescent probe is used for the detection of dibutyl phthalate (DBP).

[0029] The beneficial effects of this invention are reflected in:

[0030] (1) The liposome fluorescent probe obtained by the reaction has good selectivity and almost no fluorescence in water. When phthalates are added, the fluorescence is turned on, which can realize the efficient detection of phthalates, represented by dibutyl phthalate (DBP), in aqueous system.

[0031] (2) The present invention synthesizes a liposome fluorescent probe that can be used to detect the plasticizer phthalate. The detection method has the advantages of being non-toxic and harmless, highly sensitive, accurate and efficient, and capable of real-time and visual detection. Attached Figure Description

[0032] Figure 1 The infrared spectra of typical OH-BODIPY, N-Andro, and water-soluble probes (OH-BODIPY-N-Andro) are shown.

[0033] Figure 2 The UV absorption spectra of typical OH-BODIPY, N-Andro, and water-soluble probes (OH-BODIPY-N-Andro) are shown.

[0034] Figure 3 The fluorescence response of the water-soluble fluorescent probe (OH-BODIPY-N-Andro) to dibutyl phthalate (DBP);

[0035] Figure 4 A water-soluble fluorescent probe (OH-BODIPY-N-Andro) for dibutyl phthalate (DBP)

[0036] Selective identification;

[0037] Figure 5The fluorescence response of the water-soluble fluorescent probe (OH-BODIPY-N-Andro) to dibutyl phthalate (DBP) in baijiu (Chinese liquor). Detailed Implementation

[0038] Example 1

[0039] (1) Synthesis of hydroxyfluoroboropyrrole:

[0040] p-Hydroxybenzaldehyde (366.4 mg, 3 mmol) was dissolved in a suitable amount of dichloromethane. Under nitrogen protection, 2,4-dimethylpyrrole (700 μL, 6.5 mmol) and trifluoroacetic acid (37 μL, 0.5 mmol) were added, and the mixture was sealed and stirred overnight. A tetrahydrofuran solution (5 mL) of DDQ (681 mg, 3 mmol) was added, and the mixture was stirred at room temperature for 3 hours. A suitable amount of triethylamine was added, and after reacting for two hours, 6 mL of boron trifluoride diethyl ether was added. The mixture was stirred at room temperature for 12 hours. The reaction mixture was concentrated and extracted with dichloromethane. The organic phases were combined, dried over anhydrous sodium sulfate, and the solvent was concentrated to give a black solid OH-BODIPY. The product was separated by silica gel column chromatography, eluting with petroleum ether:ethyl acetate in a 4:1 ratio, yielding 460 mg of OH-BODIPY (45% yield).

[0041] (2) Synthesis of modified andrographolide (N-Andro)

[0042] Andro (126 mg, 0.36 mmol) was dispersed in 36 mL of a chloroform solution of p-nitrobenzaldehyde (55 mg, 0.36 mmol), and a catalyst amount of p-toluenesulfonic acid (6.2 mg, 0.036 mmol) was added. The mixture was heated under reflux at 60 °C for 4–5 h. After the reaction was complete, anhydrous Na₂CO₃ (3.8 mg, 0.036 mmol) was added, and the mixture was stirred for 2–3 h. The chloroform was removed by concentration under reduced pressure, and the mixture was redissolved in dichloromethane. The solution was washed with 3 × 10 mL of deionized water, and the aqueous phase was back-extracted with dichloromethane. The organic phases were combined, dried over anhydrous Na₂SO₄, filtered, and concentrated under reduced pressure. 10 mL of dichloromethane was added, and the mixture was heated under reflux at 50 °C for 1.5 h to completely dissolve the sample. While still hot, 30 mL of petroleum ether was added, and the mixture was allowed to stand. Remove the precipitate, add 10 mL of dichloromethane again, heat and reflux at 50 °C for 1 h, repeat three to four times to obtain 85 mg of off-white solid N-Andro, yield 58.7%.

[0043] (3) Water-soluble fluorescent probe

[0044] Dissolve OH-BODIPY (9.2 mg, 0.027 mmol) in 10 mL THF, add N-Andro (9.1 mg, 0.0189 mmol), add 10 mL DSPE-mPEG5000 (27 mg, 0.054 mmol) aqueous solution, stir for 2 h, concentrate under reduced pressure, and centrifuge to obtain a red solid water-soluble fluorescent probe.

[0045] like Figure 1 As shown, 1522cm in N-Andro -1 and 1347cm -1 In OH-BODIPY-N-Andro liposomes, the characteristic peak of the nitro group shifts to 1543 cm⁻¹, representing both asymmetric and symmetric stretching vibrations attributable to the nitro group. -1 and 1305cm -1 OH-BODIPY, 3420cm -1 The stretching vibration attributed to the hydroxyl group shifted 25 cm⁻¹ to higher wavenumbers in OH-BODIPY-N-Andro liposomes. -1 Moved to 3445cm -1 At the ester carbonyl group (1743 cm) -1 No movement occurred.

[0046] OH-BODIPY and N-Andro form water-soluble fluorescent probes through self-assembly via hydrogen bonds between nitro and hydroxyl groups.

[0047] Example 2

[0048] 25 μM aqueous solutions of OH-BODIPY, N-Andro and OH-BODIPY-N-Andro liposomes were prepared, and the UV absorption spectra of OH-BODIPY (25 μM, green), N-Andro (25 μM, black) and OH-BODIPY-N-Andro (25 μM, red) in THF were obtained.

[0049] like Figure 2 As shown, the absorption spectrum of OH-BODIPY exhibits maximum wavelengths at 245 nm and 500 nm. Analysis indicates that the absorption peak at 245 nm corresponds to the π-π* transition in the pyrrole ring structure, while the strong absorption peak at 500 nm corresponds to the S0-S1 π-π* transition. When OH-BODIPY and N-Andro are assembled at a ratio of 1:0.7 to form OH-BODIPY-N-Andro liposomes, both the absorbance and peak intensity are significantly increased.

[0050] Example 3

[0051] Prepare 3 mL of an aqueous solution (50 μg / mL) of OH-BODIPY-N-Andro liposomes and a DMSO solution of 5 mM dibutyl phthalate (DBP). Add different doses of DBP in DMSO solution using a microsyringe, incubate at room temperature for 2 minutes, and then perform fluorescent titration. (DBP concentrations a to l were 0, 5, 15, 25, 35, 45, 55, 65, 75, 85, 95, and 105 μM, respectively.)

[0052] The fluorescence intensity measurement parameters were: excitation wavelength 480 nm, slit width 5 nm.

[0053] like Figure 3 As shown, the fluorescence results indicate that when DBP is added to the aqueous solution of OH-BODIPY-N-Andro liposomes, fluorescence is activated due to the strong hydrophobic effect of DBP. Therefore, DBP can be detected by fluorescence changes.

[0054] Example 4

[0055] Selectivity is a key indicator for evaluating fluorescent probes. This study investigated the selective recognition of dibutyl phthalate (DBP) by comparing the fluorescence response of OH-BODIPY-N-Andro liposomes with the following: A: 105 μM glycerol; B: 105 μM ethylene glycol; C: 1 mg / mL BSA aqueous solution; D: 1 mg / L DMSO solution of vegetable oil; E: 105 μM n-octylamine; F: 96 μL ethyl acetate; G: 96 μL dimethyl sulfoxide; H: 96 μL tetrahydrofuran; I: 105 μM dimethyl 5-hydroxyisophthalate; J: ethyl 4-aminobenzoate; K: 105 μM methyl bromoacetate; L: methyl acrylate; M: ethyl bromoacetate; N: 96 μL acetonitrile; O: 105 μM dibutyl phthalate. (F0: initial fluorescence intensity; F: final fluorescence intensity; excitation wavelength: 480 nm; slit width: 5 nm).

[0056] Figure 4 This indicates that OH-BODIPY-N-Andro liposomes have a specific response to dibutyl phthalate (DBP).

[0057] Example 5

[0058] Dibutyl phthalate (DBP) was added to baijiu (Chinese liquor) for titration experiments. Fluorescence spectra of OH-BODIPY-N-Andro liposomes (50 μg / mL) in the liquor were obtained as a to n varied with DBP concentration (a to n were 0, 5, 35, 55, 75, 105, 115, 145, 165, 185, 195, 205, 215, 225 μM). Fluorescence intensity was measured using the following parameters: excitation wavelength 480 nm, slit width 5 nm.

[0059] Figure 5 As shown, the fluorescence intensity of the system increased with the addition of DBP. The detection limit of DBP in baijiu was 0.78 μg / g, which is far superior to the value reported in the literature.

Claims

1. A method for synthesizing a water-soluble fluorescent probe, characterized in that, The steps are as follows: Dissolve hydroxyfluoroboronpyrrole (OH-BODIPY) in tetrahydrofuran, then add solid modified andrographolide (N-Andro), add polyethylene glycol (PEG) aqueous solution, stir thoroughly, concentrate under reduced pressure, and centrifuge to obtain the target product, a water-soluble fluorescent probe. The structural formula of hydroxyfluoroboronpyrrole (OH-BODIPY) is as follows: ； The modified structure of N-Andro lactone is as follows: 。 2. The synthesis method according to claim 1, characterized in that, The molar ratio of hydroxyfluoroboronpyrrole (OH-BODIPY) to modified andrographolide (N-Andro) is 1:0.5-1, and the stirring time is 2-3 h; the volume ratio of tetrahydrofuran to PEG aqueous solution is 1:0.5-2; and the degree of polymerization of polyethylene glycol (PEG) is 1000-10000.

3. The synthesis method as described in claim 2, characterized in that, The molar ratio of hydroxyfluoroboronpyrrole to N-Andro is 1:0.7; the volume ratio of tetrahydrofuran to PEG aqueous solution is 1:1; and the degree of polymerization of polyethylene glycol PEG is 5000.

4. The synthesis method as described in claim 3, characterized in that, The hydroxyfluoroboron pyrrole is synthesized through the following steps: p-hydroxybenzaldehyde and 2,4-dimethylpyrrole are used as starting materials and concentrated in the presence of trifluoroacetic acid, DDQ, triethylamine and boron trifluoride ether, followed by silica gel column chromatography to obtain hydroxyfluoroboron pyrrole OH-BODIPY.

5. The synthesis method according to claim 1, characterized in that, The synthesis steps of the modified andrographolide are as follows: (1) Disperse androlactone Andro in a chloroform solution of p-nitrobenzaldehyde, add a catalyst amount of p-toluenesulfonic acid, and allow it to react fully; (2) After the reaction is complete, add anhydrous Na2CO3 to the mixture in step (1) and stir thoroughly at room temperature for 2-3 hours; (3) The reaction solution obtained in step (2) is concentrated under reduced pressure to remove chloroform, redissolved with dichloromethane, washed with deionized water, and extracted. (4) The organic phase obtained in step (3) is dried with anhydrous Na2SO4, filtered, and concentrated under reduced pressure; (5) Dissolve the sample in step (4) completely with dichloromethane, add petroleum ether while hot, let stand, remove the lower precipitate, and repeat the operation of adding dichloromethane and petroleum ether 3-4 times to obtain off-white solid N-Andro.

6. The synthesis method as described in claim 5, characterized in that, In step (1), the molar ratio of andrographolide, p-nitrobenzaldehyde and p-toluenesulfonic acid is 1:1:0.1-0.3, and the reaction conditions are reflux at 60°C for 4-5 hours. In step (2), the molar ratio of p-toluenesulfonic acid and anhydrous Na2CO3 is 1:1; In step (5), the volume ratio of petroleum ether to dichloromethane is 3:1, and the reaction conditions are heating at 50°C under reflux for 1.5 hours.

7. A water-soluble fluorescent probe, characterized in that, It is prepared by the method described in any one of claims 1 to 6.

8. Use of the water-soluble fluorescent probe of claim 7 for the detection of phthalates.

9. The use of the water-soluble fluorescent probe of claim 7 for the detection of dibutyl phthalate (DBP).

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