CN114805613B

CN114805613B - For detecting Fe 3+ Ethyl cellulose base flavonol fluorescent probe and preparation method and application thereof

Info

Publication number: CN114805613B
Application number: CN202210618789.1A
Authority: CN
Inventors: 杨益琴; 武杨梅; 孟志远; 寇佳丽; 王晓媛; 钱铖; 周国诚; 王忠龙; 王石发
Original assignee: Nanjing Forestry University
Current assignee: Nanjing Forestry University
Priority date: 2022-06-01
Filing date: 2022-06-01
Publication date: 2022-12-16
Anticipated expiration: 2042-06-01
Also published as: CN114805613A

Abstract

The invention discloses a method for detecting Fe ³⁺ The ethyl cellulose base flavonol fluorescent probe and the preparation method and the application thereof. The invention takes 3-hydroxy-4-acetyl biphenyl and 4-formyl benzoic acid as initial raw materials, and HBOB is generated through aldol condensation reaction; preparing HPCB by oxidizing cyclization reaction of HBOB; and esterifying the HPCB with hydroxyl on the ethyl cellulose to obtain the EC-HPCB. DMSO-H of EC-HPCB under 365nm ultraviolet light irradiation ₂ Adding Fe into O solution ³⁺ Then, the fluorescence color of the solution changes from orange yellow to colorless to Fe ³⁺ Up to a detection limit of 2.65X 10 ^‑7 mol/L, response time of 2min, can be used for detecting Fe ³⁺ The fluorescent probe has good application prospect.

Description

For detecting Fe 3+ Ethyl cellulose base flavonol fluorescent probe and preparation method and application thereof

Technical Field

The invention belongs to the technical field of fluorescence detection, and particularly relates to a method for detecting Fe ³⁺ The ethyl cellulose base flavonol fluorescent probe and the preparation method and the application thereof.

Background

Cellulose is a polysaccharide which is distributed most widely and has the largest content in the world, is also a natural high molecular compound with the most abundant reserves in the nature, and has the advantages of good hydrophilicity, low cost, good biodegradability, greenness, no toxicity and the like. China is a large country for agricultural production, cellulose resources are abundant, and the total amount of cellulose generated by crop straws only reaches more than 2.0 hundred million tons every year in China, so that the high-valued utilization of cellulose in China has attracted general attention of the whole society, and particularly, the development and utilization of cellulose-based functional materials become a hot spot of current research. Ethyl Cellulose (EC) is an ethyl ether of cellulose, a long-chain polymer having β -anhydroglucose units linked by acetal, and one of the most widely used water-insoluble cellulose derivatives. Because ethyl cellulose can be dissolved in most organic solvents and can be mixed with resin, oil wax and plasticizer, the ethyl cellulose has good processing performance. Flavonols, also known as 3-hydroxy-2-phenyl-1-benzopyran-4-ones, are a very important class of natural pigments and bioactive substances in nature and are widely distributed in plant foods such as fruits, vegetables and the like. Flavonol molecules are easy to generate an Excited State Intramolecular Proton Transfer (ESIPT) effect under the excitation of visible light, so that the flavonol molecules have excellent optical characteristics of good fluorescence intensity, high quantum yield, good light stability, large Stokes shift and the like, and due to the existence of adjacent phenolic hydroxyl groups and oxygen heteroatoms in the structure, the flavonol compounds have good complexing ability, so that the flavonol serving as a fluorescent group with excellent performance is widely applied to the field of fluorescent probes. If the flavonol derivatives are grafted to an ethyl cellulose chain by a chemical synthesis means, the novel cellulose-based flavonol fluorescent probe is synthesized by utilizing the excellent optical characteristics of good fluorescence intensity, good light stability, high quantum yield, large Stokes shift and the like of the flavonol structural units and the physicochemical characteristics of good biodegradability, good biocompatibility, high reaction activity, good processing performance and the like of the ethyl cellulose, and the defects of high cytotoxicity, low quantum yield, poor light stability, poor processing performance and the like of the traditional organic micromolecule fluorescent probe are hopefully overcome. Therefore, the development of various types of ethyl cellulose-based functional materials has very important significance, and the ethyl cellulose-based functional materials have wide application prospects in the fields of biological imaging, detection sensing, information anti-counterfeiting and the like.

Iron being predominantly Fe ²⁺ And Fe ³⁺ Is the most abundant essential micronutrient in the body. Wherein, fe ³⁺ Plays a crucial role in human respiration and cell metabolism, and maintains Fe ³⁺ Homeostasis is vital to human health. For example, fe ³ ⁺ Can lead to intracellular hypoxia and many diseases such as liver cancer, gastric adenocarcinoma and anemia. However, some serious complications, such as beta-thalassemia and hereditary hemochromatosis, are also associated with Fe ³⁺ Too high a level is relevant. In addition, due to Fe ³⁺ Migration and concentration in the environmental water system can pose a potential health hazard to the food chain. Therefore, fe is considered ³⁺ Of interest, development of a highly sensitive monitoring of Fe ³⁺ The method of (1) is very necessary. At present, fe ³⁺ The detection method mainly comprises a voltammetry method, an inductively coupled plasma mass spectrum, an inductively coupled plasma emission spectrum, an atomic absorption spectrum method, a spectrophotometry method and the like, and the technologies have the defects of complex operation, low practicability, low sensitivity and the like due to more limitation factors. Fluorescence detection technique for detecting Fe ³⁺ Has the advantages of convenient operation, high sensitivity and the like.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method for detecting Fe ³⁺ The ethyl cellulose base flavonol fluorescent probe meets the requirement of Fe ³⁺ Detects the usage requirements. The invention also provides a preparation method of the ethyl cellulose base flavonol fluorescent probe. The invention also aims to solve another technical problem of providing an application of the ethylcellulose-based flavonol fluorescent probe.

In order to solve the technical problems, the invention adopts the technical scheme that:

for detecting Fe ³⁺ The ethyl cellulose base flavonol fluorescent probe is EC-HPCB, and the structural formula is as follows:

the preparation method of the ethyl cellulose base flavonol fluorescent probe comprises the following steps:

(1) Carrying out aldol condensation reaction on 3-hydroxy-4-acetylbiphenyl and 4-formylbenzoic acid to prepare 2 '-hydroxy-4' -phenyl-4-carboxyl chalcone (HBOB); HBOB is subjected to oxidative cyclization reaction to prepare 3-hydroxy-7-phenyl-4' -carboxyl flavonol (HPCB);

(2) Esterification of HPCB with hydroxyl groups on Ethyl Cellulose (EC) produces EC-HPCB.

In the step (1), the preparation steps of HPCB are as follows:

1) Taking 5-10mmol of 3-hydroxy-4-acetylbiphenyl, 5-10mmol of 4-formylbenzoic acid and 30-60 mL of ethanol, carrying out ultrasonic treatment for 10min, adding 5-10 mL of 20% potassium hydroxide aqueous solution, reacting at room temperature for 24-48 h, and monitoring the reaction process by using thin layer chromatography; after the reaction is finished, pouring the reaction solution into ice water, then acidifying with 20% hydrochloric acid, generating a precipitate, filtering, recrystallizing in ethanol, and drying to obtain yellow HBOB;

2) Dissolving 3-6 mmol HBOB in 15-30 mL ethanol in ice bath, adding 10-20 mmol sodium hydroxide, dropwise adding 5-10 mL hydrogen peroxide with the concentration of 30%, and stirring for 5h. After the reaction was completed, the reaction mixture was poured into ice water, neutralized with 20% hydrochloric acid, and the resulting precipitate was filtered, recrystallized from ethanol, and dried to obtain HPCB.

In the step (2), the EC-HPCB is prepared by the following steps:

1) Adding 1.0-2.0 mmol of ethyl cellulose, 0.2-0.4mmol of 4- (N, N-dimethyl) aminopyridine, 0.5-1.0 mmol of HPCB and 20-40 mL of DMF into a round-bottom flask, and degassing for 20min under the protection of nitrogen; dripping 1.0-2.0 mmol of N, N' -dicyclohexylcarbodiimide dissolved in DMF into the solution at 0 ℃, and reacting for 24-48 h at room temperature;

2) After the reaction is finished, pouring the reaction solution into 100-200 mL of pure water, carrying out suction filtration, DMF/water washing and vacuum drying at 45 ℃ for 24-36 h to obtain the EC-HPCB.

The ethyl cellulose-based flavonolDetection of Fe by fluorescent probe ³⁺ The use of (1).

The application is that DMSO/H of EC-HPCB is irradiated by 365nm ultraviolet light ₂ Adding Fe into O solution ³⁺ After that, the fluorescence color of the solution changed from orange yellow to colorless.

The ethyl cellulose base flavonol fluorescent probe is used for detecting Fe in preparation ³⁺ The fluorescent probe of (1).

Has the advantages that: compared with the prior art, the invention has the following main advantages:

1) According to the application, the cellulose-based fluorescent probe obtained by grafting HPCB to the cellulose macromolecules has excellent performances of the cellulose macromolecules, and simultaneously overcomes a plurality of limitations of small molecular fluorescent compounds. Has the characteristics of good luminous performance, stable structure and the like.

2) The application is proved through experiments: DMSO/H of EC-HPCB under 365nm ultraviolet light irradiation ₂ O (DMSO∶H ₂ O = 1: 9,v/v) solution to Fe ³⁺ Then, the fluorescence color of the solution changes from orange yellow to colorless to Fe ³⁺ Up to a detection limit of 2.65X 10 ^-7 M, response time 2min, as detecting Fe ³⁺ The fluorescent probe has good application prospect.

Drawings

FIG. 1 is a chart of (a) the infrared spectrum of HPCB, (b) the infrared spectrum of EC, and (c) the infrared spectrum of EC-HPCB;

FIG. 2 is DMSO/H of EC-HPCB ₂ O(DMSO∶H ₂ O = 1: 9,v/v) solution to Fe ³⁺ Front and back fluorescence spectra;

FIG. 3 is DMSO/H of EC-HPCB ₂ O(DMSO∶H ₂ O = 1: 9,v/v) solution, adding fluorescence spectra of different metal ions;

FIG. 4 is DMSO/H of EC-HPCB ₂ O(DMSO∶H ₂ O = 1: 9,v/v) solution with different concentrations of Fe ³⁺ Fluorescence spectrum of (2).

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, specific embodiments thereof are described in detail below with reference to examples of the specification.

Example 1

Synthesizing an ethyl cellulose base flavonol fluorescent probe, wherein the reaction formula is as follows:

the preparation method comprises the following specific steps:

1) In a 50mL flask, 5mmol of 3-hydroxy-4-acetylbiphenyl, 5mmol of 4-formylbenzoic acid and 30mL of ethanol were added, ultrasonic treatment was performed for 10min, 5mL of 20% aqueous potassium hydroxide solution was added, reaction was performed at room temperature for 48h, and the progress of the reaction was monitored by thin layer chromatography. After the reaction is finished, the reaction solution is poured into ice water, the ice water is acidified by hydrochloric acid with the concentration of 20%, and the generated precipitate is filtered, recrystallized and dried to obtain yellow HBOB.

2) Under the ice-bath condition, 3mmol HBOB is dissolved in 15mL ethanol, 10mmol sodium hydroxide is added, 5mL hydrogen peroxide with the concentration of 30% is dripped, and the mixture is stirred for 5 hours. After the reaction was completed, the reaction solution was poured into ice water, neutralized with a 20% hydrochloric acid aqueous solution, and the resulting precipitate was filtered and recrystallized in ethanol to obtain HPCB.

3) Adding 1.0mmol of ethyl cellulose, 0.2mmol of 4- (N, N-dimethyl) aminopyridine, 0.5mmol of HPCB and 20mL of DMF into a round-bottom flask, and degassing for 20min under the protection of nitrogen; 1.0mmol of N, N' -dicyclohexylcarbodiimide dissolved in DMF was added dropwise to the solution at 0 ℃ and reacted at room temperature for 48 hours. After the reaction, the reaction solution was poured into 100mL of purified water, precipitated, filtered, and the filter cake was washed with DMF/water (DMF/water = 1: 1,v/v) and dried under vacuum at 45 ℃ for 24h to obtain EC-HPCB.

The structure of an ethyl cellulose base flavonol fluorescent probe (EC-HPCB) is analyzed by FT-IR. FIG. 1 is an infrared spectrum of HPCB, EC and EC-HPCB, respectively. The infrared spectrogram of EC-HPCB appears at 3500cm ^-1 And 3300cm- ¹ Two peaks of (2) are O-H stretching vibration absorption peaks on EC and HPCB, 2982cm ^-1 And 2923cm ^-1 The absorption peak is asymmetric and symmetric stretching vibration absorption peak of C-H of methyl and methylene in the molecule, 1743cm ^-1 C = O stretching vibration absorption peak, indicating successful grafting of HPCB onto the ethylcellulose molecular backbone.

Example 2

Adding EC-HPCB to DMSO/H ₂ O(DMSO∶H ₂ O = 1: 9,v/v), prepared as a solution with a concentration of 0.1mg/mL, measured in DMSO/H on a spectrofluorometer using spectrofluorometry ₂ O(DMSO∶H ₂ O = 1: 9,v/v) in solution, as shown in fig. 2. The results show that in DMSO/H ₂ O(DMSO∶H ₂ O = 1: 9,v/v), without addition of Fe ³⁺ When the solution fluoresces orange yellow, fe is added ³⁺ Then, the fluorescence intensity was sharply reduced, and the maximum emission wavelength was 565nm (excitation wavelength was 365nm, excitation slit broad band was 12.0nm, and emission slit broad band was 3.8 nm).

Adding EC-HPCB to DMSO/H ₂ O(DMSO∶H ₂ O = 1: 9,v/v), and a solution with a concentration of 0.1mg/mL was prepared, wherein 1 part of the solution was used as a blank, and Fe was added to each of the other parts ³⁺ ，Zn ²⁺ ，Mg ²⁺ ， Pb ²⁺ ，Hg ²⁺ ，Ca ²⁺ ，Ag ⁺ ，Al ³⁺ ，Co ² ⁺ ，Cd ²⁺ ，Ba ²⁺ ，K ⁺ ，Ni ²⁺ ，Mn ²⁺ ，Cr ³⁺ ，La ³⁺ ， Cu ²⁺ And Fe ²⁺ The fluorescence emission spectrum of the solution was measured on a fluorescence spectrophotometer by a fluorescence spectrometry method, and the result is shown in fig. 3. As can be seen from FIG. 3, fe was added ³⁺ Then, the maximum emission wavelength of the solution was 565nm, and the fluorescence intensity of the solution was significantly reduced. While the fluorescence intensity of the solution changes very little when other analytes are added. This indicates that EC-HPCB is on Fe ³⁺ Has good selectivity.

Adding EC-HPCB to DMSO/H ₂ O(DMSO∶H ₂ O = 1: 9,v/v), preparing a solution with the concentration of 0.1mg/mL, and adding Fe with different concentrations on a fluorescence spectrophotometer by adopting a fluorescence spectrum titration method ³⁺ Fluorescence emission spectra after ionization. As shown in fig. 4. The results show that with Fe ³⁺ The gradual increase of the concentration and the gradual decrease of the fluorescence signal intensity of the EC-HPCB at 565nm indicate that the EC-HPCB can be used for detecting Fe in the solution ³⁺ Concentration of, to Fe ³⁺ Up to 2.65X 10 ^-7 M。

Claims

1. For detecting Fe ³⁺ The ethyl cellulose base flavonol fluorescent probe is characterized in that the structural formula is as follows:

。

2. the method for preparing an ethylcellulose-based flavonol fluorescent probe as claimed in claim 1, which is characterized by comprising the following steps:

(1) Performing aldol condensation reaction on 3-hydroxy-4-acetylbiphenyl and 4-formylbenzoic acid to prepare 2 '-hydroxy-4' -phenyl-4-carboxychalcone; oxidizing and cyclizing 2' -hydroxy-4 ' -phenyl-4-carboxyl chalcone to obtain 3-hydroxy-7-phenyl-4 ' -carboxyl flavonol;

(2) The 3-hydroxy-7-phenyl-4 '-carboxyl flavonol is esterified with the hydroxy on the ethyl cellulose to prepare the ethyl cellulose-3-hydroxy-7-phenyl-4' -carboxyl flavonol.

3. The method for preparing an ethylcellulose-based flavonol fluorescent probe according to claim 2, wherein in the step (1), the 3-hydroxy-7-phenyl-4' -carboxyflavonol is prepared by the following steps:

1) Taking 5 to 10mmol of 3-hydroxy-4-acetylbiphenyl, 5 to 10mmol of 4-formylbenzoic acid and 30 to 60mL of ethanol, carrying out ultrasonic treatment for 10min, adding 5 to 10mL of 20% potassium hydroxide aqueous solution, reacting at room temperature for 24 to 48h, and monitoring the reaction process by using thin layer chromatography; after the reaction is finished, pouring the reaction liquid into ice water, then acidifying with 20% hydrochloric acid, generating precipitate, filtering, recrystallizing in ethanol, and drying to obtain yellow 2 '-hydroxy-4' -phenyl-4-carboxyl chalcone;

2) Dissolving 3 to 6mmol of 2 '-hydroxy-4' -phenyl-4-carboxyl chalcone in 15 to 30mL of ethanol under an ice bath, adding 10 to 20mmol of sodium hydroxide, dropwise adding 5 to 10mL of 30% hydrogen peroxide, and stirring for 5 h; after the reaction is finished, pouring the reaction mixture into ice water, neutralizing with hydrochloric acid with the concentration of 20%, filtering the generated precipitate, recrystallizing in ethanol, and drying to obtain the 3-hydroxy-7-phenyl-4' -carboxyl flavonol.

4. The method for preparing an ethylcellulose-based flavonol fluorescent probe according to claim 2, wherein in the step (2), the steps of preparing ethylcellulose-3-hydroxy-7-phenyl-4' -carboxyflavonol are as follows:

1) 1.0 to 2.0mmol of ethyl cellulose and 0.2 to 0.4mmol of 4- (C)N,NAdding (E) -dimethyl) aminopyridine, 0.5 to 1.0mmol of 3-hydroxy-7-phenyl-4' -carboxyl flavonol and 20 to 40mL of DMF into a round bottom flask, and degassing for 20min under the protection of nitrogen; 1.0 to 2.0mmol of DMF at 0 DEG C N,N' -dicyclohexylcarbodiimide is dripped into the solution and reacts for 24 to 48 hours at room temperature;

2) After the reaction is finished, pouring the reaction liquid into 100 to 200mL of pure water, carrying out suction filtration on the precipitate, washing the precipitate with DMF/water, and then carrying out vacuum drying at 45 ℃ for 24 to 36 hours to obtain the ethyl cellulose-3-hydroxy-7-phenyl-4' -carboxyl flavonol.

5. The ethylcellulose-based flavonol fluorescent probe as claimed in claim 1 for detecting Fe ³⁺ The use of (1).

6. The use according to claim 5, wherein the DMSO/H of ethylcellulose-3-hydroxy-7-phenyl-4' -carboxyflavonol is under the irradiation of 365nm ultraviolet light ₂ Adding Fe into O solution ³⁺ After that, the fluorescence color of the solution changed from orange-yellow to colorless.

7. The ethylcellulose-based flavonol fluorescent probe as claimed in claim 1In preparation for detecting Fe ³⁺ The fluorescent probe of (1).