Preparation method of enhanced fluorescent probe for detecting formaldehyde

Abstract

The invention belongs to the technical field of harmful substance detection, and particularly relates to a preparation method of an enhanced fluorescent probe for detecting formaldehyde, which comprises the following steps: dissolving 4-methylpyridine and 1, 3-propane sultone in dry acetonitrile to obtain a product 1; dissolving the product 1 in dry acetonitrile, and adding p-acetamidobenzaldehyde to obtain a product 2; dissolving the product 2 in ethanol, and adding hydrochloric acid to obtain a fluorescent probe MA-QC; the method comprises the following steps: dissolving a fluorescent probe MA-QC in DMSO (Dimethylsulfoxide) to prepare mother liquor; the fluorescent probe provided by the invention has the advantages of enhanced recognition of formaldehyde, simple synthesis route, simple and convenient detection equipment and method, and can be used for qualitative and quantitative detection of formaldehyde in environment and biological systems.

Description

Technical Field

[0001] This invention belongs to the field of hazardous substance detection technology, specifically relating to a method for preparing a formaldehyde-enhanced fluorescent probe. Background Technology

[0002] Formaldehyde, a widespread environmental pollutant, originates from various sources, primarily indoors and industrially. In indoor environments, engineered wood products (such as plywood and MDF), furniture, paints, and wallpaper adhesives are the main sources of continuous formaldehyde release. Additionally, some daily chemical products, such as cleaning agents and textile finishing agents, may also contain formaldehyde. At the industrial level, production processes in the chemical, wood processing, and textile industries release formaldehyde into the atmosphere. In natural processes, the decomposition of organic matter or forest fires also produce small amounts of formaldehyde. Its harmful effects on organisms are significant. Short-term exposure to high concentrations in humans can irritate the eyes and respiratory mucous membranes, causing acute symptoms such as tearing and coughing. Long-term exposure may damage the immune and nervous systems and increase the risk of malignant tumors such as leukemia and nasopharyngeal carcinoma, with children and pregnant women being particularly vulnerable. For plants and animals, formaldehyde inhibits photosynthesis, leading to yellowing leaves and stunted growth. Long-term exposure in animals may cause liver and kidney damage and affect their reproductive capacity, thus posing a potential threat to ecosystem stability. Therefore, there is an urgent need to develop a highly sensitive fluorescent probe for detecting formaldehyde (FA), which has important scientific significance and application prospects for detecting FA in the environment.

[0003] Fluorescence detection requires relatively simple instruments, offers high selectivity and sensitivity, has a wide detection range, rapid response time, and is non-destructive to the sample. It shows great potential for formaldehyde pollution detection in the environment and ecosystems. Summary of the Invention

[0004] To address the problems existing in current fluorescence detection technologies, this invention provides an enhanced fluorescent probe for formaldehyde detection, which has a simple synthesis process, high yield, fast response speed, good selectivity, high sensitivity, and low detection limit.

[0005] To solve the above-mentioned technical problems, the present invention is implemented as follows: The preparation method of the formaldehyde-enhanced fluorescent probe includes the following steps: A method for preparing a formaldehyde-enhanced fluorescent probe includes the following steps: (1) 4-methylpyridine and 1,3-propanesulfonyl lactone were reacted in dry acetonitrile to give product 1; (2) React product 1 with p-acetaminobenzaldehyde in dry acetonitrile to obtain product 2; (3) The product 2 was reacted with hydrochloric acid in dry ethanol, and after neutralization and purification, the fluorescent probe MA-QC was obtained; (4) Dissolve the fluorescent probe MA-QC in dimethyl sulfoxide to obtain the formaldehyde-enhanced fluorescent probe.

[0006] Further, in step (1), the molar ratio of 4-methylpyridine to 1,3-propanesulfonyl lactone is 1:1.5.

[0007] Furthermore, in step (2), the molar ratio of product 1 to p-acetaminobenzaldehyde is 1:1.

[0008] Furthermore, in step (3), the molar ratio of product 2 to hydrochloric acid is 1:10.

[0009] Furthermore, the reaction temperature in step (1) is 80–100°C, and the reaction time is 11–13 hours.

[0010] Furthermore, the reaction temperature in step (2) is 70–90°C, and the reaction time is 3–5 hours.

[0011] Furthermore, the reaction temperature in step (3) is 70–90°C, and the reaction time is 5–6 hours.

[0012] The fluorescent probe MA-QC prepared by the above-described method for preparing an enhanced fluorescent probe for formaldehyde detection has the following structure: .

[0013] The present invention also provides an application of the above-mentioned fluorescent probe MA-QC in the detection of formaldehyde.

[0014] The specific reaction process of the fluorescent probe obtained by the above-mentioned method for preparing the formaldehyde-enhanced fluorescent probe is as follows: , This invention utilizes the reaction of 4-methylpyridine, 1,3-propanesulfonyl lactone, p-acetaminobenzaldehyde, and hydrochloric acid to prepare the desired fluorescent probe. This fluorescent probe, in the presence of formaldehyde under dimethyl sulfoxide:water (1:1) conditions, exhibits a significant fluorescence change with increasing formaldehyde concentration. The fluorescent probe demonstrates rapid response, high selectivity, and high sensitivity for formaldehyde detection. Compared to some existing detection technologies, the fluorescent chemical probe of this invention requires less investment, has a simpler synthesis route, is easier to process, and can directly and rapidly and specifically identify formaldehyde in a dimethyl sulfoxide:water (1:1) system, making it particularly valuable for everyday applications. Attached Figure Description

[0015] The present invention will now be described in detail through specific embodiments. These embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art. As used throughout the specification and claims, the terms "comprising" or "including" are open-ended and are interpreted as "comprising but not limited to". The following description is a preferred embodiment for carrying out the invention; however, this description is intended to illustrate the general principles of the specification and is not intended to limit the scope of the invention. The scope of protection of the invention is determined by the appended claims. Unless otherwise specified, all reagents and materials used in the present invention are commercially available.

[0016] Figure 1 The NMR spectrum of the prepared fluorescent probe MA-QC is shown below. Figure 2 The NMR C-spectrum of the prepared fluorescent probe MA-QC; Figure 3 The fluorescence emission spectra of the fluorescent probe MA-QC at different formaldehyde concentrations are shown. Figure 4 The fitted curve of fluorescence intensity of fluorescent probe MA-QC as formaldehyde concentration changes and the corresponding function graph are shown. Figure 5 The selectivity of the fluorescent probe MA-QC for formaldehyde and 28 of its potential interfering substances; Figure 6 Evaluation of the anti-interference ability of the fluorescent probe MA-QC to recognize formaldehyde in the presence of 28 interfering ions; Figure 7 This is a statistical graph showing the fluorescence intensity of the fluorescent probe MA-QC before and after formaldehyde recognition as a function of pH changes in the test system. Figure 8 The results of the MA-QC fluorescent probe on a sample that may contain formaldehyde are shown. The concentration of the added ions was 2 × 10⁻⁶. -2 The concentration was mol / L, and the excitation wavelength was 445 nm. (Note: The probe concentration was 10 μM; the FA response time was approximately 1 min.) Detailed Implementation

[0017] Example 1

[0018] (1) Preparation of product 2.

[0019] 4-Methylpyridine (3 mmol) and 1,3-propanesulfonyl lactone (4.5 mmol) were added to a 10 mL round-bottom flask containing dry acetonitrile and heated under reflux for 12 h. The reaction progress was monitored by thin-layer chromatography until the reaction was completed. The mixture was then cooled to room temperature, filtered to obtain the retained solid, which was the desired product. The solid was then dried under vacuum to synthesize product 1.

[0020] Product 1 (2 mmol) was dissolved in 10 mL of dry acetonitrile, and p-acetaminobenzaldehyde (2 mmol) was added. The mixture was heated under reflux for 4 h, and the reaction progress was monitored by thin-layer chromatography until the reaction was completed. The reaction solution was then cooled to room temperature, filtered, washed with ice-cold ethanol, and dried under vacuum to synthesize product 2.

[0021] (2) Use product 2 and hydrochloric acid to synthesize a probe.

[0022] Product 2 (1 mmol) and hydrochloric acid (10 mmol) were dissolved in 15 mL of dry ethanol, heated to reflux for 12 h, and the reaction progress was monitored by thin-layer chromatography until the reaction was completed. After cooling to room temperature, the solution was adjusted to neutral with sodium hydroxide aqueous solution, and purified by rotary evaporation and column chromatography. The mobile phase for column chromatography was dichloromethane:methanol with a volume ratio of 6:1. The purified product solution was then subjected to reduced pressure rotary evaporation to remove the solvent, and dried under vacuum to obtain probe MA-QC.

[0023] Weigh out 1 mmol of MA-QC and dissolve it in DMSO to prepare a 1 mM stock solution. This yields the formaldehyde-enhanced fluorescent probe for detection.

[0024] Formaldehyde testing: Take 10 5 mL sample vials and add 20 μL of the fluorescent probe solution MA-QC obtained in Example 1 (the concentration of the fluorescent probe is 10 μM). Then, add [FA]=0 (a) and 5.5×10 to 9 sample vials respectively. -5 mol / L (b), 1.1×10 -4 mol / L (c), 1.65×10 -4 mol / L(d), 2.2×10 -4 mol / L (e), 2.75×10 -4 mol / L (f), 3.3 × 10 -4 mol / L(g), 3.85×10 -4 mol / L(h), 4.4×10 -4 mol / L(i), 5×10 -4 A formaldehyde solution of mol / L (j) was stirred at room temperature for 1 min, and the fluorescence intensity of these samples was measured at an excitation wavelength of 445 nm. The fluorescence intensity emission spectrum changes of the 10 samples are shown in the figure. Figure 3 The measurement results showed that the fluorescence intensity of the fluorescent probe at 590 nm gradually increased with the gradual increase of formaldehyde ion concentration. Based on... Figure 3The fluorescence intensity changes can be used to plot the corresponding fitted function curve and the corresponding function graph (y=ax+b, a= 8.149, b= 2833.73, R). 2 =0.9997) See Figure 4 .

[0025] Selectivity and anti-interference capability test of probe MA-QC: Take 30 5 mL sample vials and add 20 μL of the MA-QC solution (10 μM concentration) prepared with the fluorescent probe obtained in Example 1 to each vial. Then, add a solution with a concentration of 2×10⁻⁶ μM to each vial. -2 20 μL of each of the mol / L other analytes and 50 mM formaldehyde were added to the remaining 29 sample vials. Sample No. 1 was the blank sample, and sample No. 30 was the formaldehyde sample. After stirring at room temperature for 1 min, the fluorescence emission intensity of each of the 30 samples was measured at an excitation wavelength of 445 nm and an emission wavelength of 590 nm. The results are shown in the table below. Figure 5 The results showed that the probe MA-QC specifically responds to formaldehyde.

[0026] Take 29 5 mL sample vials and add 20 μL of the MA-QC solution (10 μM concentration) prepared with the fluorescent probe obtained in Example 1 to each vial. Then, add a 2×10⁻⁶ solution to each vial. -2 20 μL of each of the other analytes (mol / L) were added to the remaining 28 sample vials, with sample #1 serving as a blank. 20 μL of 50 mM formaldehyde was then added to 29 of the sample vials. After stirring at room temperature for 1 min, the fluorescence emission intensity of each of the 29 samples was measured at 445 nm excitation and 590 nm emission wavelength. The results are shown below. Figure 6 The results show that the MA-QC probe has high specificity for formaldehyde detection, strong anti-interference performance, and meets the requirements for the analysis of complex practical samples.

[0027] pH range test for formaldehyde: Twenty-four 5 mL sample vials were prepared, and a 1:1 pH mixture of dimethyl sulfoxide and water (adjusted with sodium hydroxide solution and dilute hydrochloric acid solution) was added to each vial. The pH values ​​were 2.00 (a), 3.00 (b), 4.00 (c), 5.00 (d), 6.00 (e), 7.00 (f), 8.00 (g), 9.00 (h), 10.00 (i), 11.00 (j), 12.00 (k), and 13.00 (l). Each pH value was tested twice. For the first 12 vials, only 20 μL of the fluorescent probe stock solution was added. For the last 12 vials, 20 μL of the fluorescent probe stock solution and 20 μL of 50 mM formaldehyde solution were added. After stirring at room temperature for 1 min, the fluorescence intensity of each sample was measured at an excitation wavelength of 445 nm. The fluorescence intensity emission spectrum changes of the 24 samples are shown in the figure. Figure 7 .

[0028] Practical application test of fluorescent probe MA-QC: Immerse a 1 × 0.5 cm rectangular gel sample in 10 mL of dimethyl sulfoxide and shake for 1 hour. Filter to remove solid impurities. Transfer the filtrate to a 20 mL volumetric flask and dilute to volume with water to obtain the test solution. Then, take three 5 mL sample vials, add 2 mL of the test solution and 20 μL of the fluorescent probe stock solution to each vial. Next, add 5 × 10⁻⁶ μL of [FA] = 0 mol / L (a) to each of the three sample vials. -5 mol / L (b), 1×10 -4 After stirring at room temperature for 1 min with mol / L (c), the fluorescence intensity of these samples was measured at an excitation wavelength of 445 nm. The results are shown in the figure. Figure 8 The obtained data were then analyzed to obtain the recovery rate and RSD value. The results showed that the probe MA-QC had a good recovery rate (100.86-103.11%) and a low RSD value (1.79-2.64%) when detecting actual samples, and can be used to quantify the formaldehyde content in actual samples.

[0029] The above embodiments are used to explain and illustrate the present invention, but not to limit the present invention. Any modifications and changes made to the present invention within the spirit and scope of the claims fall within the protection scope of the present invention.

Claims

1. A method for preparing a formaldehyde-enhanced fluorescent probe, characterized in that, Includes the following steps: (1) 4-methylpyridine and 1,3-propanesulfonyl lactone were reacted in dry acetonitrile to give product 1; (2) React product 1 with p-acetaminobenzaldehyde in dry acetonitrile to obtain product 2; (3) The product 2 was reacted with hydrochloric acid in dry ethanol, and after neutralization and purification, the fluorescent probe MA-QC was obtained; (4) Dissolve the fluorescent probe MA-QC in dimethyl sulfoxide to obtain the formaldehyde-enhanced fluorescent probe.

2. The formaldehyde-enhanced fluorescent probe for detection according to claim 1, characterized in that: In step (1), the molar ratio of 4-methylpyridine to 1,3-propanesulfonyl lactone is 1:1.

5.

3. The method for preparing a formaldehyde-enhanced fluorescent probe according to claim 2, characterized in that: In step (2), the molar ratio of product 1 to p-acetaminobenzaldehyde is 1:

1.

4. The method for preparing a formaldehyde-enhanced fluorescent probe according to claim 3, characterized in that: In step (3), the molar ratio of product 2 to hydrochloric acid is 1:

10.

5. The method for preparing a formaldehyde-enhanced fluorescent probe according to claim 4, characterized in that: The reaction temperature in step (1) is 80-100℃ and the reaction time is 11-13 hours.

6. The method for preparing a formaldehyde-enhanced fluorescent probe according to claim 5, characterized in that: The reaction temperature in step (2) is 70-90℃ and the reaction time is 3-5 hours.

7. The method for preparing a formaldehyde-enhanced fluorescent probe according to claim 6, characterized in that: The reaction temperature in step (3) is 70-90℃ and the reaction time is 5-6 hours.

8. A fluorescent probe MA-QC prepared by the method for preparing a formaldehyde-enhanced fluorescent probe according to any one of claims 1 to 7, characterized in that, It has the following structure: 。 9. The application of the fluorescent probe MA-QC according to claim 8 in the detection of formaldehyde.

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