Preparation method and application of a fluorescent probe based on enone structure

Abstract

The present invention belongs to the field of chemical analysis and testing, and in particular to a method for preparing a fluorescent probe based on an enone structure and its application. First, 2-aminoacetophenone and p-dimethylaminobenzaldehyde are used as raw materials, ethanol is used as a solvent, and sodium hydroxide is used as a base, and stirred overnight at room temperature. The product is then reacted with dansyl chloride at room temperature in a pyridine solution to obtain a crude final product. The obtained crude product is then separated by column chromatography using petroleum ether and ethyl acetate as developing agents to obtain a final orange pure product. The fluorescent probe obtained by the present invention has good optical properties and fluorescence selectivity of bisulfite ions, and can achieve fluorescence detection of bisulfite ions.

Description

Technical Field

[0001] The invention belongs to the field of chemical analysis and testing, and in particular relates to a preparation method of a fluorescent probe based on an enone structure and an application thereof. Background Art

[0002] Sulfur dioxide (SO 2 ) is a typical reactive sulfur species and the simplest sulfur oxide compound. SO 2 It is a gas present in neutral pH aqueous solution as a balance between bisulfite and sulfite ions. Sulfur dioxide derivatives also play an important role in daily life, especially in pharmaceutical products, beverages and food preservation. Bisulfite / sulfite can also be used as a food processing aid, color stabilizer and antioxidant to avoid oxidation and microbial growth. In addition, bisulfite / sulfite enters the human body through food, beverages and medicines, and because sulfurizing agents (sulfur dioxide, metabisulfite, bisulfite and sulfite) are widely used as preservatives, it can be very dangerous to humans. People are using various analytical techniques to detect and track trace amounts of HSO 3 - A lot of efforts have been made in this regard.

[0003] Currently, the HSO 3 - There are many methods to detect HSO in complex samples. The main detection methods are: colorimetry, electrochemistry, chromatography, chemiluminescence and capillary electrophoresis. Among them, colorimetry and chemiluminescence have low sensitivity and poor selectivity. Chromatography and other methods require expensive equipment or cumbersome sample processing. Compared with these methods, the fluorescent probe method has the advantages of simple operation, high sensitivity and good selectivity, and is a good choice for detecting HSO in complex samples. 3 - To this end, a rapid, simple, and sensitive method for detecting HSO was designed and synthesized. 3 - of fluorescent reagents. Summary of the invention

[0004] The present invention provides a fluorescent probe based on an enone structure, the structural formula of the fluorescent probe is:

[0005]

[0006] The present invention also provides a specific preparation method of a fluorescent probe based on an enone structure: the chemical reaction formula for preparing the fluorescent probe is:

[0007]

[0008] The specific steps are as follows:

[0009] (1) 2-aminoacetophenone (intermediate 1) and p-dimethylaminobenzaldehyde (intermediate 2) were first dissolved in ethanol at a molar equivalent ratio of 1:1, and then 3-5 equivalents of sodium hydroxide were added and stirred at room temperature for 4 hours. After the reaction was completed, the ethanol was dried, water was added to filter out the solid residue, and the solid residue was recrystallized from ethanol to obtain a bright orange powder (intermediate 3);

[0010] (2) The bright orange powder (intermediate 3) obtained in step (1) and dansyl chloride are first reacted in a pyridine solution at a molar ratio of 1:1-1:2 with stirring for 1 hour. After the reaction is completed, the pyridine is dried, the crude product is extracted with ethyl acetate, the organic phase is taken, dried over anhydrous sodium sulfate, evaporated to dryness under reduced pressure, and finally purified by column chromatography using a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 3:1 as a developing solvent to obtain the final product.

[0011] The present invention also provides an application of the fluorescent probe: the prepared dansyl chloride fluorescent probe based on the enone structure is applied to the detection of bisulfite ions, and the bisulfite ions are directly detected in an acetic acid-water solution (water content 80%), which is rapid, simple, highly selective, and the detection limit is as low as 1 μm / L.

[0012] The specific application method is: add 2 μL of anion solution to the 96-well plate (the anions in each well are PO 4 3- , CO 3 2- OH - 、F - , Cl - Br - ,I - , S 2- 、SO 4 2- 、SO 3 2- , HSO 3 - , concentration of 10 mM / mL), 196 μL of acetic acid-water solution and 2 μL of dansyl chloride fluorescent probe based on enone structure (concentration of 1×10 -3 mol / L), and a solution containing dansyl chloride fluorescent probe without ions (Blank) was used as a comparison. The solutions in each well were mixed evenly, and the fluorescence intensity of the solution in each well was detected by a microplate reader. The results showed that the fluorescence intensity of the solution containing bisulfite ions at 500nm was twice that of the solution without bisulfite ions; and the fluorescent probe had no particularly obvious fluorescence intensity changes for other anions, thus showing the selective recognition of the fluorescent probe for bisulfite ions in acetic acid-water solution.

[0013] The invention solves the problem of selective recognition of bisulfite ions by a fluorescent probe in an acetic acid-water solution. From the reaction phenomenon, the fluorescence intensity of the fluorescent probe is significantly enhanced before and after the addition of the bisulfite ions.

[0014] The beneficial effects of the present invention are as follows: the raw materials of the present invention are easy to obtain, the enone structure is introduced into the fluorescent probe through a two-step reaction, the synthesis method is simple, the reaction conditions are easy to control, and after the reaction is completed, a pure product can be obtained through a simple post-treatment; as a chemical probe for detecting bisulfite ions, the dansyl chloride fluorescent probe based on the enone structure has high sensitivity and good selectivity, and can quickly and directly identify bisulfite ions in an acetic acid-water solution, for example, in an acetic acid-water solution, the detection limit of the bisulfite ions is 1 μm / L. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The fluorescent probe prepared in Example 1 was 4×10 -3 mol / L concentration fluorescence spectra after the reaction with different ions in acetic acid-water solution.

[0016] Figure 2 The fluorescent probe prepared in Example 1 was 4×10 -3 mol / L in acetic acid-water solution after reacting with different concentrations of bisulfite ions.

[0017] Figure 3 This is a line graph of the fluorescence intensity at 500 nm of the fluorescent probe prepared in Example 1 after reacting with bisulfite ions in acetic acid with a water content of 0-80%.

[0018] Figure 4 This is the hydrogen spectrum of the fluorescent probe prepared in Example 1. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with embodiments:

[0020] Embodiment 1:

[0021] (1) 2-Aminoacetophenone (Intermediate 1) (0.135 g, 1 mmol) and p-dimethylaminobenzaldehyde (Intermediate 2) (0.149 g, 1 mmol) were dissolved in 5 mL of ethanol, and sodium hydroxide (200 mg, 5 mmol) was added. The mixture was stirred at room temperature for 4 h. After the reaction was completed, the ethanol was dried, and water was added to filter out the solid residue. The solid residue was recrystallized from ethanol to obtain 0.187 g of bright orange powder Intermediate 3;

[0022] (2) The intermediate 3 (0.133 g, 0.5 mmol) obtained in step (1) and dansyl chloride (0.134.5 g, 0.5 mmol) were dissolved in 5 mL of pyridine solution and stirred for 1 hour. After the reaction was completed, the pyridine was dried and the crude product was extracted with ethyl acetate. The organic phase was taken and dried over anhydrous sodium sulfate and evaporated to dryness under reduced pressure to obtain an orange crude product. Finally, the product was purified by column chromatography using a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 3:1 as the developing solvent to obtain 0.1931 g of the final pure product.

[0023] Figure 1 The probe prepared in Example 1 was 4×10 -3 mol / L concentration in acetic acid-water solution after the reaction with different ions. The figure shows that the concentration of the drop is 1×10 -2 mol / L of different ion solutions, the fluorescence intensity changes of the probe. When 1×10 -2 mol / L bisulfite ion solution, the fluorescence intensity of the probe at 500nm increased significantly (the curve indicated by the arrow); while the probe did not show any obvious fluorescence changes for other ions in acetic acid-water solution, indicating that the probe has a strong fluorescence response to HSO 3 - selective recognition.

[0024] Figure 2 The probe prepared in Example 1 was 4×10 -3 mol / L in acetic acid-water solution with different concentrations of bisulfite ions. 3 - With the decrease of concentration, the fluorescence intensity of the probe gradually weakened. When its final concentration was 1 μmol / L, the fluorescence peak at 500 nm was still comparable to that without HSO 3 - The background fluorescence curve of the probe is different from that of HSO. 3 - The detection limit is low and the sensitivity is high.

[0025] Figure 3 The line graph of the fluorescence intensity at 500nm of the fluorescent probe prepared in Example 1 after reacting with bisulfite ions in acetic acid with a water content of 0-80%. The graph shows that in acetic acid with a water content of 0%, 20%, 40%, 60%, and 80%, the fluorescence intensity of the probe solution at 500nm is relatively weak, and the intensity is about 1300a.u.; after adding bisulfite ions, the fluorescence at 500nm is significantly enhanced, and the maximum fluorescence intensity is about 2400a.u., so acetic acid with a water content of 80% is selected for detection.

[0026] Figure 4 This is the hydrogen spectrum of the dansyl chloride fluorescent probe based on the enone structure prepared in Example 1. 1 H NMR (400 MHz, CDCl 3 ): δ11.87(s,1H),8.44(d,J=8.4Hz,1H),8.37(d,J=8.8Hz,1H),8.32-8.27(m,1H),7.75(d,J=8.0Hz,1H),7.65-7.60(m,2H),7.55(s, 1H),7.47(dd,J=8.4,4.3Hz,3H),7.35(s,1H),7.08-7.04(m,2H),7.02-6.96(m,1H),6.68(d,J=8.8Hz,2H),3.07(s,6H),2.75(s,6H).

[0027] Example 2

[0028] (1) 2-Aminoacetophenone (Intermediate 1) (0.135 g, 1 mmol) and p-dimethylaminobenzaldehyde (Intermediate 2) (0.149 g, 1 mmol) were dissolved in 5 mL of ethanol, and sodium hydroxide (120 mg, 3 mmol) was added. The mixture was stirred at room temperature for 4 h. After the reaction was completed, the ethanol was dried, and water was added to filter out the solid residue. The solid residue was recrystallized from ethanol to obtain 0.153 g of bright orange powder Intermediate 3;

[0029] (2) The intermediate 3 (0.133 g, 0.5 mmol) obtained in step (1) was stirred with dansyl chloride (0.269 g, 1 mmol) in 5 mL pyridine solution for 1 hour. After the reaction was completed, the pyridine was dried and the crude product was extracted with ethyl acetate. The organic phase was taken and dried over anhydrous sodium sulfate. The solvent was dried to obtain an orange crude product. Finally, the product was purified by column chromatography using a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 3:1 as the developing solvent to obtain 0.1856 g of the final pure product.

Claims

1. A fluorescent probe based on an enone structure, characterized in that: The structural formula of the fluorescent probe is:

2. A method for preparing a fluorescent probe based on an enone structure as claimed in claim 1, characterized in that: The preparation method steps are as follows: (1) dissolving 2-aminoacetophenone and p-dimethylaminobenzaldehyde in ethanol, adding sodium hydroxide, stirring at room temperature, and after the reaction is completed, spinning the ethanol to dryness, adding water to filter out the solid residue, and recrystallizing from ethanol to obtain a bright orange powder; (2) reacting the bright orange powder obtained in step (1) with dansyl chloride in a pyridine solution at room temperature, and finally purifying by column chromatography to obtain a fluorescent probe based on an enone structure.

3. The method for preparing a fluorescent probe based on an enone structure according to claim 2, characterized in that: In step (1), the molar ratio of 2-aminoacetophenone, p-dimethylaminobenzaldehyde and sodium hydroxide is 1:1:3-5.

4. The method for preparing a fluorescent probe based on an enone structure according to claim 2, characterized in that: The reaction time of step (1) is 4 hours under stirring at room temperature.

5. The method for preparing a fluorescent probe based on an enone structure according to claim 2, characterized in that: The structural formula of the bright orange powder obtained by the step is 6. The method for preparing a fluorescent probe based on an enone structure according to claim 2, characterized in that : In step (2), the molar ratio of the orange solid to dansyl chloride is 1:1-1:2, and the reaction time at room temperature is 1 hour.

7. The method for preparing a fluorescent probe based on an enone structure according to claim 2, characterized in that : During the purification in step (2), the developing solvent is a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 3:

1.

8. An application of the fluorescent probe based on enone structure as claimed in claim 1, characterized in that: The fluorescent probe based on the enone structure can detect the bisulfite ion under the condition that the acetic acid-water solution is used as the solution.

9. The use of the fluorescent probe based on enone structure as claimed in claim 8, characterized in that: The water content of the acetic acid-water solution is 80%; the concentration range of the fluorescent probe is 1-10 μM.

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