Preparation method of silicon quantum dot-Fe < 3 + > fluorescent probe and application of silicon quantum dot-Fe < 3 + > fluorescent probe in detection of glyphosate pesticide residues

Abstract

The invention discloses a preparation method of a silicon quantum dot-Fe < 3 + > fluorescent probe and application of the silicon quantum dot-Fe < 3 + > fluorescent probe in detection of glyphosate pesticide residues, belongs to the field of analytical chemistry, and solves the problems that an existing detection method is long in detection time consumption, complex in sample pretreatment and difficult in high-throughput analysis. The preparation method comprises the following steps: introducing a newly prepared sodium ascorbate solution and a 3-aminopropyltrimethoxysilane solution into ultrapure water for reaction; dialyzing the solution in distilled water to remove unreacted solvent, and storing the obtained solution in a dark place at room temperature; carrying out rotary evaporation on the solution until the solution is viscous, pumping by a vacuum pump until the solution is dry, and dissolving by distilled water to obtain a silicon quantum dot solution; and incubating the silicon quantum dot solution and Fe < 3 + > at room temperature to form the silicon quantum dot-Fe < 3 + > fluorescent probe. The preparation method is simple, and reaction products are easy to separate and purify; the method is simple and convenient in glyphosate detection operation, good in selectivity, rapid in response and high in sensitivity, and can be used for rapid and quantitative detection of glyphosate pesticide residues in vegetables.

Description

Technical Field

[0001] This invention belongs to the field of analytical chemistry, specifically relating to a silicon quantum dot-Fe 3+ Preparation method of fluorescent probe and its application in the detection of glyphosate pesticide residues. Background Technology

[0002] In recent years, with the widespread use of pesticides in modern agriculture, pesticide residues and their impact on environmental pollution, food safety, and human health have attracted increasing attention. Glyphosate is a broad-spectrum, non-selective organophosphorus herbicide and one of the most widely used and consumed herbicides in the world. Glyphosate can effectively inhibit the growth of annual weeds, perennial plants, and herbaceous plants non-selectively, and has the properties of low cost and low toxicity to mammals. However, excessive and long-term use of glyphosate can lead to its continuous accumulation in the environment and organisms, and it can enter the human body through the food chain, posing a potential threat to human health. Recent studies have shown that glyphosate can cause various health hazards, including lung cancer, lymphoma, and pancreatic cancer, and it has been classified as a Group 2A carcinogen by the World Health Organization (WHO). More than 30 countries or regions worldwide have included glyphosate residue limits in their relevant regulations and standards. Therefore, the analysis and detection of glyphosate in environmental and biological samples is of great significance.

[0003] Methods for detecting glyphosate pesticide residues mainly include gas chromatography, high-performance liquid chromatography, chromatography-mass spectrometry, electrochemical analysis, and enzyme-linked immunosorbent assay (ELISA). While these traditional methods have achieved good results in detecting glyphosate pesticide residues, they typically require highly specialized experimental equipment and operators, necessitate large and expensive equipment, and have limitations such as long detection times, complex sample pretreatment, and difficulty in high-throughput analysis. In contrast, fluorescence sensing detection methods offer advantages such as ease of operation, readily available equipment, high sensitivity, strong specificity, short response time, and real-time high-throughput identification and detection. Therefore, applying fluorescence sensing technology to the detection of glyphosate pesticide residues has broad application prospects. Summary of the Invention

[0004] The purpose of this invention is to provide a silicon quantum dot-Fe 3+ The method for preparing fluorescent probes aims to address the problems of expensive equipment, long detection time, complex sample pretreatment, and difficulty in high-throughput analysis in existing methods for detecting glyphosate pesticide residues.

[0005] Another object of the present invention is to provide a silicon quantum dot-Fe 3+ Application of fluorescent probes in the detection of glyphosate pesticide residues.

[0006] The technical solution of this invention is: (one) A silicon quantum dot-Fe 3+ The preparation method of the fluorescent probe includes the following steps: A. Under stirring, the freshly prepared sodium ascorbate solution (SA) and 3-aminopropyltrimethoxysilane solution (APTMS) were introduced into ultrapure water for reaction; B. Dialyze the solution obtained in step A in distilled water to remove unreacted solvent. Store the resulting solution at room temperature away from light. C. Rotary evaporate the solution obtained in step B until it becomes viscous, vacuum pump it to dryness, and dissolve it with distilled water to obtain a silicon quantum dot solution; D. Mix silicon quantum dot solution with Fe 3+ Incubation at room temperature (25°C) forms silicon quantum dots-Fe 3+ Fluorescent probe.

[0007] As a further improvement of the present invention, in step A, the concentration of sodium ascorbate solution is 90-110 mmol / L, the concentration of 3-aminopropyltrimethoxysilane solution is 90-110 mmol / L, and the volume ratio of sodium ascorbate solution, 3-aminopropyltrimethoxysilane solution, and ultrapure water is 1.8-2.2:1.4-1.8:6.2-6.6.

[0008] As a further improvement of the present invention, in step A, the reaction time is 1-2 hours.

[0009] As a further improvement of the present invention, in step B, the dialysis time is 7-9 hours.

[0010] As a further improvement of the present invention, in step C, the concentration of the silicon quantum dot solution is 40-45 g / L.

[0011] As a further improvement of the present invention, in step D, silicon quantum dots and Fe 3+ The molar ratio of the substances is 1:2-3.

[0012] As a further improvement of the present invention, in step D, the incubation time is 5-15 minutes. (two) A silicon quantum dot-Fe 3+ Application of fluorescent probes in the detection of glyphosate pesticide residues.

[0014] Silicon quantum dots (SiQDs) are zero-dimensional fluorescent nanomaterials with advantages such as low cost, strong luminescence, good photostability, and good biocompatibility. The silicon quantum dots prepared in this invention are easy to synthesize and purify, and these silicon quantum dots are compatible with Fe. 3+The resulting fluorescence sensing system enables sensitive fluorescence recovery (Off-On) detection of glyphosate pesticides. The detection mechanism is as follows: Figure 1 As shown, the SiQD synthesized in this invention exhibits strong green fluorescence, Fe 3+ It can interact with negatively charged functional groups such as carboxyl and hydroxyl groups on the SiQD surface, leading to fluorescence quenching of the system. When glyphosate pesticide is added, due to the interaction between glyphosate and Fe... 3+ The coordination between them is stronger than that between SiQD and Fe. 3+ The interaction between them allows glyphosate to replace SiQD and Fe. 3+ The system's fluorescence is restored through this process. Therefore, this method can detect glyphosate pesticides by detecting the fluorescence in an "on-off-on" manner. Compared with previously published glyphosate detection methods, this method has advantages such as simple operation, good selectivity, rapid response, high sensitivity, and low detection limit. Silicon quantum dots-Fe 3+ Fluorescent sensing systems can be applied to the rapid detection and analysis of glyphosate pesticide residues in vegetables.

[0015] This invention relates to silicon quantum dots-Fe 3+ The fluorescent probe emits strong green fluorescence under a 365 nm UV lamp. At the maximum excitation wavelength of 380 nm, it has a strong fluorescence emission spectrum of 450–600 nm, with a maximum emission wavelength of 500 nm.

[0016] Silicon quantum dots-Fe 3+ The fluorescent probe solution was mixed with a 0–10 μg / mL glyphosate pesticide solution for the detection of glyphosate. The fluorescence spectrum revealed the presence of silicon quantum dots-Fe... 3+ The fluorescence intensity of the fluorescent probe increases with increasing glyphosate pesticide concentration, and there is a good linear relationship between fluorescence intensity and glyphosate pesticide concentration. Therefore, silicon quantum dots-Fe 3+ The composite system can be used as a probe for detecting glyphosate pesticides, enabling rapid and quantitative detection of glyphosate pesticide content, with a detection limit of 394.74 ng / mL.

[0017] Compared with the prior art, the present invention has the following advantages: 1. The preparation method is simple, and the reaction products are easy to separate and purify.

[0018] 2. The glyphosate detection method is simple to operate, has good selectivity, fast response, and high sensitivity.

[0019] 3. It can be used for rapid and quantitative detection of glyphosate pesticide residues in vegetables. Attached Figure Description

[0020] Figure 1 This is a diagram illustrating the detection mechanism of the present invention; Figure 2 It is the silicon quantum dot-Fe in Example 2 of this invention. 3+ UV-Vis-fluorescence spectrum of glyphosate pesticide detected by fluorescent probe; Figure 3 It is the silicon quantum dot-Fe in Example 2 of this invention. 3+ Fluorescence titration diagram of glyphosate by fluorescent probe; Figure 4 This is a linear fitting graph of glyphosate detection in Example 2 of the present invention; Figure 5 It is the silicon quantum dot-Fe in Example 3 of this invention. 3+ Time-varying graph of glyphosate detection by fluorescent probe; Figure 6 It is the silicon quantum dot-Fe in Example 3 of this invention. 3+ The effect of fluorescent probes on the detection of interfering substances; Figure 7 This is a fluorescence response diagram of the detection system for different pesticides in Example 3 of the present invention. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1: Silicon quantum dots-Fe 3+ Preparation method of fluorescent probe.

[0023] A. Under magnetic stirring, 2 mL of freshly prepared sodium ascorbate solution (100 mmol / L) and 1.6 mL of 3-aminopropyltrimethoxysilane solution (100 mmol / L) were introduced into 6.4 mL of ultrapure water and reacted for 1 hour. B. Dialyze the solution obtained in step A in distilled water for 8 hours to remove unreacted solvent. Store the resulting solution at room temperature away from light. C. Place the solution obtained in step B in a round-bottom flask and rotary evaporate until viscous. Then, vacuum pump the solution to dryness to obtain 0.8526 g. Dissolve the solution in 20 mL of distilled water to obtain a silicon quantum dot solution. Calculate the concentration of silicon quantum dots to be 42.63 g / L. D. Mix 4 mL of solution containing 0.11 mg / mL silicon quantum dots with 40 μM Fe 3+ The solution was incubated at room temperature (25°C) for 10 min to form silicon quantum dots-Fe 3+ Fluorescent probes are used to detect glyphosate pesticides.

[0024] Example 2, Silicon quantum dots-Fe 3+ Applications of fluorescent probes in detecting glyphosate pesticides: linearity and sensitivity.

[0025] In the silicon quantum dot-Fe3+ The fluorescent probe was mixed with 10 μg / mL glyphosate pesticide, and the results of glyphosate pesticide detection were as follows: Figure 2-4 As shown. The silicon quantum dots themselves are light orange in solution, but exhibit distinct green fluorescence under 365 nm ultraviolet light, with the maximum fluorescence emission peak at 500 nm (e.g., ...). Figure 2 (As shown). The fluorescence emission of this probe system at 500 nm is weaker compared to that of a single silicon quantum dot. When silicon quantum dot-Fe... 3+ After the fluorescent probe was reacted with 10 μg / mL glyphosate, the fluorescence intensity at 500 nm of the system increased significantly (e.g., Figure 3 (As shown). Meanwhile, the probe exhibits a wide linear range (0–10 μg / mL) and a low detection limit of 394.74 ng / mL (as shown). Figure 4 (As shown in the figure). This result demonstrates that the present invention can detect glyphosate pesticides by observing fluorescence intensity. The detection method is simple and easy to implement, and the probe has high sensitivity for glyphosate detection, making it suitable for trace qualitative and quantitative detection of glyphosate pesticides.

[0026] Example 3: Silicon quantum dots-Fe 3+ Time response and selective application of glyphosate pesticides detected by fluorescent probes.

[0027] In the silicon quantum dot-Fe 3+ Add 10 μg / mL glyphosate pesticide to the fluorescent probe. For example... Figure 5 As shown, silicon quantum dots-Fe 3+ The fluorescent probe for glyphosate detection has a short reaction time, reaching equilibrium within 5 minutes, which is beneficial for achieving rapid and ultrasensitive detection of glyphosate pesticides in complex sample systems.

[0028] In the silicon quantum dot-Fe 3+ Common biological interfering agents (potassium ions, sodium ions, calcium ions, magnesium ions, barium ions, glucose, lactose, xylose, and sodium acetate) and various organophosphorus pesticides (glyphosate, malathion, methyl parathion, methamidophos, and dimethoate) were added sequentially to the fluorescent probe at a concentration of 100 μg / mL. The fluorescence emission spectrum of the fluorescent sensor was measured under 380 nm excitation light, and the results are as follows: Figure 6 and 7 As shown. Silicon quantum dots-Fe 3+ The fluorescence of the fluorescent probe increased significantly after the addition of glyphosate, while the addition of other interfering substances did not cause significant changes in fluorescence. These results indicate that the probe exhibits excellent selective recognition ability for glyphosate.

[0029] Example 4: Application of quantitative detection of glyphosate pesticide in actual samples.

[0030] Potato and yam samples (purchased from a local supermarket) were selected and pretreated: First, the soil on the surface of the potato and yam samples was rinsed off, and the samples were crushed. 1g of sample was placed in an extraction bottle, and 15mL of acetonitrile was added. The mixture was ultrasonically homogenized for 30min. The extract was centrifuged at 10000rpm for 10min, and the supernatant was collected. The supernatant was filtered through a 0.22μM membrane to remove impurities. The filtrate was then rotary evaporated to dryness, and 4mL of glyphosate solution of different concentrations (6μg / mL, 8μg / mL, and 10μg / mL) was added to each solution.

[0031] In the silicon quantum dot-Fe 3+ Different concentrations of glyphosate solution were added to the fluorescent probe. Under 380 nm excitation light, the fluorescence emission peak intensity of the detection system at 500 nm was measured, and the result was substituted into the following equation to calculate the concentration of glyphosate in the sample: Y = 0.02052X + 1.003, where X is the glyphosate concentration and Y is the fluorescence emission peak intensity at 500 nm.

[0032] The test results are shown in Table 1.

[0033]

[0034] As shown in Table 1, the recovery rate of glyphosate in actual potato and yam tuber samples using the spiked recovery method was 96.63%–103.25%, with a relative standard deviation of 0.51%–1.23%. The error between the measured glyphosate concentration and the corresponding spiked concentration was very small. This result indicates that the silicon quantum dots-Fe prepared in this invention… 3+ Fluorescent probes have good accuracy in detecting glyphosate in actual potato and yam samples, and can quantitatively detect trace amounts of glyphosate in actual samples, making them highly practical.

Claims

1. A silicon quantum dot-Fe 3+ A method for preparing a fluorescent probe, characterized in that... Includes the following steps: A. Under stirring, the freshly prepared sodium ascorbate solution and 3-aminopropyltrimethoxysilane solution were introduced into ultrapure water for reaction; B. Dialyze the solution obtained in step A in distilled water to remove unreacted solvent. Store the resulting solution at room temperature away from light. C. Rotary evaporate the solution obtained in step B until it becomes viscous, vacuum pump it to dryness, and dissolve it with distilled water to obtain a silicon quantum dot solution; D. Mix silicon quantum dot solution with Fe 3+ Incubation at room temperature forms silicon quantum dots-Fe 3+ Fluorescent probe.

2. A silicon quantum dot-Fe according to claim 1 3+ A method for preparing a fluorescent probe, characterized in that: In step A, the concentration of sodium ascorbate solution is 90-110 mmol / L, the concentration of 3-aminopropyltrimethoxysilane solution is 90-110 mmol / L, and the volume ratio of sodium ascorbate solution, 3-aminopropyltrimethoxysilane solution, and ultrapure water is 1.8-2.2:1.4-1.8:6.2-6.

6.

3. A silicon quantum dot-Fe according to claim 2 3+ A method for preparing a fluorescent probe, characterized in that: In step A, the reaction time is 1-2 hours.

4. A silicon quantum dot-Fe according to claim 1 3+ A method for preparing a fluorescent probe, characterized in that: In step B, the dialysis time is 7-9 hours.

5. A silicon quantum dot-Fe according to claim 1 3+ A method for preparing a fluorescent probe, characterized in that: In step C, the concentration of the silicon quantum dot solution is 40-45 g / L.

6. A silicon quantum dot-Fe according to claim 1 3+ A method for preparing a fluorescent probe, characterized in that: In step D, silicon quantum dots react with Fe 3+ The molar ratio of the substances is 1:2-3.

7. A silicon quantum dot-Fe according to claim 6 3+ A method for preparing a fluorescent probe, characterized in that: In step D, the incubation time is 5-15 minutes.

8. A silicon quantum dot-Fe according to any one of claims 1-7 3+ Silicon quantum dots-Fe prepared by fluorescent probe preparation method 3+ Application of fluorescent probes in the detection of glyphosate pesticide residues.

Images