High-specificity selectivity method and device for rapidly detecting glyphosate and 2, 4-D propionic acid pesticides through solvent regulation and control

Abstract

The invention discloses a solvent-controllable high-specific selectivity method and device for rapidly detecting glyphosate and 2, 4-propanoic acid pesticides, a fluorescent probe is adopted for detection, aniline and p-hydroxybenzaldehyde are weighed and jointly dissolved in glacial acetic acid for reaction, and then ammonium acetate and biphenyl formyl are added until raw materials are completely converted; mixing the L-1 with urotropine according to a molar ratio, dissolving the mixture in trifluoroacetic acid, then adding an iced sodium bicarbonate solution, and performing post-treatment and purification to obtain yellow green granular powder L-2; the preparation method comprises the following steps: dissolving L-2 and 2-hydrazinopyrazine in ultra-dry ethanol, carrying out a reflux reaction at 95 DEG C overnight, concentrating a reaction solution through a rotary evaporator, and finally carrying out suction filtration and drying to obtain an orange-yellow solid product L-3, namely the fluorescent probe. The probe is specially used for detecting glyphosate and 2, 4-D propionic acid, shows high-selectivity response to glyphosate in a pure methanol solvent, is rapid in detection process and high in sensitivity, not only widens the application range of the probe, but also highlights the adaptability of the probe in an actual sample.

Description

Technical Field

[0001] This invention relates to the field of trace detection technology, and in particular to a solvent-tunable rapid detection method and apparatus for glyphosate and 2,4-drop propionic acid pesticides with high specificity and selectivity. Background Technology

[0002] Pesticides play a crucial role in modern agricultural production and public health management, especially in controlling pests, ensuring food security, and protecting human health. However, with the widespread use of pesticides, their abuse and residue problems are becoming increasingly prominent, leading to pesticide accumulation in soil, water sources, and agricultural products, which in turn endangers human health through the food chain. Glyphosate and 2,4-D propionic acid, as common herbicides, are widely used due to their high efficiency and broad spectrum, but their persistent residues and potential toxicity in the environment urgently require the development of simple, sensitive, and efficient detection methods to achieve real-time monitoring of pesticide residues.

[0003] Currently, traditional pesticide detection techniques such as enzyme inhibition methods, immunoassays (including colloidal gold immunochromatography and enzyme-linked immunosorbent assay), high-performance liquid chromatography, and gas chromatography can quantitatively analyze pesticide residues to some extent. However, these methods have significant limitations. For example, they are usually costly, have cumbersome operating procedures, require specialized equipment and personnel training, and have low detection sensitivity and are time-consuming, making it difficult to meet the needs of rapid on-site detection. In particular, for common pesticides such as glyphosate and 2,4-D propionic acid, existing methods have limited applicability in complex environmental matrices (such as soil, water bodies, and crop samples), and cannot achieve high-throughput, real-time monitoring, thus limiting their widespread application in agricultural production and food safety. Summary of the Invention

[0004] The purpose of this invention is to provide a solvent-tunable rapid detection method and apparatus for glyphosate and 2,4-D propionic acid pesticides with high specificity and selectivity. It is specifically designed for the detection of glyphosate and 2,4-D propionic acid, exhibiting a high selective response to glyphosate in pure methanol solvent. The detection process is rapid and highly sensitive, which not only broadens the application range of the probe but also highlights its adaptability in real samples.

[0005] The above-mentioned technical objective of the present invention is achieved through the following technical solution: A solvent-tunable rapid detection method for glyphosate and 2,4-D propionic acid pesticides with high specificity and selectivity employs a fluorescent probe, which is prepared by the following steps: S1. Weigh aniline and p-hydroxybenzaldehyde, dissolve them together in glacial acetic acid, and stir the reaction at room temperature for 1 hour. Then, slowly add ammonium acetate and bibenzoyl to the reaction system, gradually raise the temperature to 120°C and continue the reaction for 20 hours. During this period, monitor the reaction progress with TLC until the raw materials are completely converted. After the reaction is completed, slowly add glacial sodium peroxide solution to the reaction system to adjust the pH to neutral. After filtration and washing, obtain a light pink solid L-1 and dry it. S2. The obtained L-1 was mixed with urotropine in a molar ratio and dissolved in trifluoroacetic acid. The mixture was heated to 110°C and stirred for 11 hours. The reaction endpoint was confirmed by TLC. After the reaction was completed, the reaction system was cooled to room temperature. Then, glacial sodium bicarbonate solution was slowly added until no bubbles were generated. After post-treatment purification, yellow-green granular powder L-2 was obtained. S3. Dissolve L-2 and 2-hydrazinopyrazine together in ultra-dry ethanol, add one drop of glacial acetic acid as a catalyst, and reflux at 95°C overnight. During the reaction, the system gradually changes from yellow to orange-yellow, accompanied by the precipitation of solid. The reaction is confirmed to be complete by TLC monitoring. After concentrating the reaction solution by rotary evaporation, the obtained solid is washed in ice-cold methanol and stirred for 12 hours. Finally, after filtration and drying, the orange-yellow solid product L-3 is obtained, which is the fluorescent probe. .

[0006] Further: In S1, the amount of glacial acetic acid is 15 ml, and the molar ratio of aniline, p-hydroxybenzaldehyde, ammonium acetate and bibenzoyl is 1:1:1:1.

[0007] Further: In S2, the trifluoroacetic acid is 30 ml, the purification is column chromatography, and the volume ratio of the elution phase is petroleum ether: ethyl acetate = 10:1, and the molar ratio of L-1 to hexamethylenetetramine is 1:4.

[0008] Furthermore, all reactions S1-S3 were carried out under nitrogen protection.

[0009] This invention also provides a solvent-tunable rapid detection method for glyphosate with high specificity and selectivity, using the fluorescent probe described in any one of claims 1-4, wherein the detection method is colorimetric and includes the following steps: S1. Dissolve glyphosate in ultrapure water to prepare a pesticide dilution solution, and dissolve L-3 in chromatographic grade dimethyl sulfoxide to prepare an L-3 solution; S2. Add methanol, L-3 solution, and pesticide dilution solution to the centrifuge tube in sequence, and control the volume ratio of methanol, L-3 solution, and pesticide dilution solution to be 3900uL:50uL:50uL. Then the fluorescence test can be performed.

[0010] Furthermore: in S1, the molar concentration of the L-3 solution is 10 μM; the molar concentration of the glyphosate solution is 40 mM; in S2, the interval between spraying the glyphosate solution and the L-3 solution is 15-60 minutes.

[0011] This invention also provides a solvent-tunable rapid detection method for 2,4-drop propionic acid pesticides with high specificity and selectivity, using a fluorescent probe as described in any one of claims 1-4, wherein the detection method is colorimetric and includes the following steps: S1. Dissolve 2,4-drops of propionic acid in methanol to prepare a pesticide dilution solution; dissolve L-3 in chromatographic grade dimethyl sulfoxide to prepare an L-3 solution. S2. Add L-3 solution, pesticide dilution solution, and methanol sequentially to a centrifuge tube, and control the volume ratio of methanol, L-3 solution, and pesticide dilution solution to be 3900uL:50uL:50uL, and then perform fluorescence testing.

[0012] The present invention also provides a solvent-tunable rapid detection device for glyphosate and 2,4-drop propionic acid pesticides with high specificity and selectivity, the device being a fluorescent test strip.

[0013] Furthermore, the preparation of the fluorescent test strip includes the following steps: S1. Cut neutral filter paper into circular test papers with a diameter of 8-15 mm, immerse them in the prepared L-3 solution and dry them at room temperature to obtain fluorescent test paper; S2. Add different concentrations of the pesticide to be tested to the fluorescent test paper and observe the fluorescence response of the test paper under normal sunlight. S3. Continue to add glyphosate solutions of different concentrations prepared in step S2 to the test paper, and observe the fluorescence response of the test paper under normal sunlight.

[0014] In summary, the present invention has the following beneficial effects: Firstly, this invention is specifically designed for the detection of glyphosate and 2,4-D propionic acid. It exhibits a high selectivity response to glyphosate in pure methanol solvent, and the detection process is rapid and highly sensitive. This not only broadens the application range of the probe but also highlights its adaptability in real samples. Secondly, this invention not only broadens the application range of probes, but also highlights their adaptability in actual samples; Thirdly, the fluorescent probe of this invention is simple in design and can be prepared by conventional synthesis methods without the need for complex instruments, which significantly reduces detection costs and time. Attached Figure Description

[0015] Figure 1 The synthetic route for the fluorescent probe L-3 of this invention is as follows: Figure 2This is the proton NMR spectrum of the fluorescent probe L-3 of this invention; Figure 3 This is a fluorescence intensity diagram at 525 nm of the fluorescent probe L-3 of this invention after reacting with different concentrations of glyphosate and other pesticides; Figure 4 This is a comparison of fluorescence intensity at 525 nm after the fluorescence probe L-3 of this invention reacts to different concentrations of glyphosate. Figure 5 This is a comparison of fluorescence enhancement at 525nm over time for the fluorescent probe L-3 of this invention to recognize pesticides; Figure 6 This is a comparison of the fluorescence intensity of the fluorescent probe L-3 of this invention after extraction with glyphosate from different soils and the fluorescence intensity of the probe alone without pesticides. Figure 7 This is a color comparison diagram of the fluorescent probe L-3 of this invention and glyphosate in methanol under normal sunlight; Figure 8 This is a color comparison image of the test paper soaked with fluorescent probe L-3 of the present invention under normal sunlight after different pesticides were added; Figure 9 This is a fluorescence intensity diagram at 575 nm of the fluorescent probe L-3 of the present invention after reacting with 2,4-drops of propionic acid and other pesticides in a mixed solution of methanol and water (methanol:water = 0.05:0.95); Figure 10 This is a comparison of the fluorescence intensity at 525 nm after the reaction of the fluorescent probe L-3 of the present invention with different concentrations of 2,4-drop propionic acid in a mixed solution of methanol and water (methanol:water = 0.05:0.95). Figure 11 This is a comparison of fluorescence enhancement over time in a mixed solution of methanol and water (methanol:water = 0.05:0.95) for identifying pesticides using the fluorescent probe L-3 of this invention at 575 nm. Figure 12 This is a color comparison diagram of the fluorescent probe L-3 of this invention and glyphosate in methanol under a 365nm ultraviolet lamp; Figure 13 This is a comparison of the color development of the fluorescent probe L-3 of the present invention under ultraviolet light and normal sunlight after spraying pesticides on 8 different leaves in a mixed solution of methanol and water (methanol:water = 0.05:0.95) and under ultraviolet light after spraying probe L-3. Figure 14 These are color comparison images of test strips soaked in fluorescent probe L-3 and then treated with different pesticides under a 365nm UV lamp. Figure 15In the figure, ab represents the fluorescence images of glyphosate or 2,4-propionic acid detected by the fluorescent probe L-3 in soil extracts spiked with the pesticides glyphosate or 2,4-propionic acid from six different regions. Figure 16 For this invention, different actual samples such as wheat, soybeans, seawater, lake water and beer were selected, and different concentrations of glyphosate and 2,4-drop propionic acid were added using the standard addition method. The data table of spiked recovery rate was obtained by detecting the spiked recovery rate using the fluorescent probe L-3. Detailed Implementation

[0016] The present invention will be further described in detail below with reference to the accompanying drawings.

[0017] In the description of this invention, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0018] Example 1, referring to Figure 1-2 A solvent-tunable rapid detection method for glyphosate and 2,4-D propionic acid pesticides with high specificity and selectivity is proposed, employing a fluorescent probe for detection. The fluorescent probe is prepared by the following steps: S1. Weigh out aniline and p-hydroxybenzaldehyde, dissolve them together in 15 ml of glacial acetic acid, stir and react for 1 hour at room temperature, then slowly add ammonium acetate and bibenzoyl to the reaction system, and control the molar ratio of aniline, p-hydroxybenzaldehyde, ammonium acetate and bibenzoyl to be 1:1:1:1. The temperature was then gradually increased to 120°C and the reaction was continued for 20 hours. During this period, the reaction process was monitored in real time using TLC technology until the raw materials were completely converted, indicating that the reaction had reached its endpoint. After the reaction was completed, the reaction system was cooled to room temperature. Then, ice-cold sodium peroxide solution was slowly added to the reaction system, and the pH of the reaction solution was carefully adjusted to neutral using an acid-base adjuster. The pH of the reaction solution was 7.0. The solid precipitate generated was then collected by vacuum filtration, and then thoroughly washed with deionized water to finally obtain a light pink solid product L-1, which was dried, vacuum dried, weighed, and its yield was calculated. S2. The obtained L-1 was mixed with hexamethylenetetramine at a molar ratio of 1:4 and dissolved in 30 ml of trifluoroacetic acid. The mixture was heated to 110 °C and stirred for 11 hours. The reaction endpoint was confirmed by TLC. After the reaction was completed, the reaction system was cooled to room temperature, and then glacial sodium bicarbonate solution was slowly added until no bubbles were generated. The mixture was then purified by column chromatography, and the volume ratio of the eluent phase was controlled to be petroleum ether: ethyl acetate = 10:1. Finally, yellow-green granular powder L-2 was obtained. S3. Dissolve L-2 and 2-hydrazylpyrazine together in ultra-dry ethanol that has been strictly dehydrated, then add one drop of glacial acetic acid as a catalyst, and then place the reaction system in an oil bath at 95°C and reflux overnight for 12-14 hours. During the reaction, the system gradually changed from an initial yellow color to an orange-yellow color, accompanied by the precipitation of solid. TLC monitoring confirmed the reaction was complete. All three steps were carried out under nitrogen protection. The solvent was then removed by rotary evaporation under reduced pressure. The resulting solid was washed in ice-cold methanol at 0-5°C with stirring for 12 hours to remove impurities. Finally, it was filtered and thoroughly dried in a vacuum oven to obtain a high-purity orange-yellow solid product L-3, which is the target fluorescent probe molecule. .

[0019] Example 2: A solvent-tunable rapid detection method with high specificity and selectivity for glyphosate and 2,4-D propionic acid pesticides. The detection method is for the detection of glyphosate and 2,4-D propionic acid residues in soil and includes the following steps: S1. Dissolve L-3 in chromatographic grade dimethyl sulfoxide to prepare L-3 probe stock solution; dissolve glyphosate and 2,4-drop propionic acid standard in ultrapure water respectively to prepare high-concentration pesticide standard stock solutions. S2. Randomly select topsoil from different geographical environments, such as woodlands and parks. After natural air drying, grinding and sieving, accurately weigh 1.0 g of soil sample and place it in a centrifuge tube. Add 100 µM glyphosate solution or 50 µM 2,4-drop propionic acid solution to the soil sample respectively. Let it stand to allow it to penetrate to simulate pesticide residue as the experimental group. At the same time, weigh an equal amount of soil sample that has not been sprayed with pesticide as a blank parallel control group. S3. Add extraction solvent to the soil sample and place it in an ultrasonic cleaner for ultrasonic extraction for 10 minutes to ensure that the pesticides adsorbed by the soil particles are fully desorbed. Then it was placed in a centrifuge and centrifuged at 8000 rpm for 5 minutes. The supernatant was then filtered through a microporous membrane and the filtrate was collected as the soil extract to be tested. S4. Establish separate detection systems for comparative analysis: For glyphosate detection: Soil extract was added to pure methanol solvent, L-3 probe solution was added, and color changes were observed under normal sunlight and fluorescence changes were observed under 365 nm ultraviolet light; For the detection of 2,4-D propionic acid: Soil extract was added to a mixed solvent of methanol and water in a volume ratio of 0.05:0.95, and L-3 probe solution was added. Fluorescence enhancement was observed under a 365 nm UV lamp. The final concentration of L-3 probe in the entire detection system was 10 µM, and the total volume was 4 mL, of which the volume of soil extract added was 50 µL.

[0020] Example 3: A solvent-tunable rapid detection method with high specificity and selectivity for glyphosate and 2,4-D propionic acid pesticides. The detection method is applicable to various real samples, including crops, environmental water samples, and food and beverages, for the detection of glyphosate and 2,4-D propionic acid residues, and includes the following steps: S1. Dissolve L-3 in chromatographic grade dimethyl sulfoxide to prepare a probe stock solution; dissolve glyphosate and 2,4-drop propionic acid in ultrapure water to prepare a series of standard solutions of different concentrations. S2. Pretreatment of different real samples: For solid samples, such as wheat, soybeans and other crops, accurately weigh the crushed sample, add the extraction solvent, and after ultrasonic extraction and high-speed centrifugation, take the supernatant and filter it to obtain the sample solution to be tested. For liquid samples, such as beer and environmental water samples, beer samples are degassed by ultrasound to remove carbon dioxide. For environmental water samples, such as lake water and seawater, the samples are allowed to settle directly, and then filtered through a microporous membrane to remove insoluble impurities to obtain the test sample solution. S3. The standard addition method was used to conduct a spike recovery experiment. Then, glyphosate or 2,4-drops of propionic acid standard solution of known concentration were added to the above-mentioned test sample solution, and the mixture was mixed evenly to prepare the spiked sample. The spiked concentrations for glyphosate detection were set to 1 µM, 3 µM, and 5 µM, while the spiked concentrations for 2,4-D propionic acid detection were set to 0.3 µM, 0.5 µM, and 0.7 µM. S4. Establish a detection system and calculate the recovery rate: Detection of glyphosate: The spiked sample was added to a methanol solvent system, an L-3 probe was added, and the fluorescence intensity at 525 nm was measured. Detection of 2,4-drop propionic acid: The spiked sample was added to a mixed solvent system of methanol:water = 0.05:0.95, and an L-3 probe was added. The fluorescence intensity at 575 nm was measured. The concentration was calculated according to the standard curve and compared with the actual added concentration to calculate the spiked recovery rate. The calculated spiked recovery rate ranged from 91.3% to 116%, and the relative standard deviation (RSD) was less than 5.2%.

[0021] Example 4: A solvent-tunable rapid method for detecting glyphosate with high specificity and selectivity. This method is for detecting glyphosate residues in soil and includes the following steps: S1. Dissolve L-3 in DMSO to prepare an L-3 solution with a molar concentration of 10 μM; dissolve glyphosate in ultrapure water to prepare a glyphosate solution with a molar concentration of 40 mM, wherein the molar ratio of fluorescent probe L-3 to glyphosate is 1:1-15. S2. Randomly select soil samples from different farmlands and weigh them with the same weight of 1.0 g. Spray glyphosate solution on the soil and wait for the pesticide to penetrate. At the same time, weigh the same mass of unsprayed soil samples as parallel controls. Use 10 mL of ultrapure water to centrifuge and extract soil components to simulate the pesticide residue situation in the soil after pesticide spraying. S3. Use filter paper as the support for probe L-3. Cut filter paper with a diameter of 8-15 mm, soak it in dimethyl sulfoxide solution of L-3 for 2-5 minutes, take it out and dry it, and add glyphosate and 9 comparative pesticides. S4. Take L-3 solution and glyphosate solution respectively and add them to methanol. The volume ratio of methanol to L-3 solution and glyphosate solution is 3.9 mL: 50 uL: 50 uL. Perform fluorescence spectroscopy detection. The fluorescence test parameters are as follows: excitation slit is 10 nm, emission slit is 10 nm, and excitation wavelength is 360 nm. The final detection concentration of L-3 solution was 10 μM, and the final detection concentration range of chiral glyphosate solution was 0-150 μM.

[0022] like Figure 3 As shown, when the fluorescent probe L-3 was reacted with different pesticides, only glyphosate showed a significant fluorescence enhancement, indicating that the L-3 prepared in this invention can detect glyphosate with high specificity. like Figure 4 As shown, the fluorescent probe L-3 was reacted with glyphosate for 0-60 minutes, and fluorescence tests were performed at different time intervals. The fluorescence intensity of the fluorescent probe reached a plateau after 1 minute of reaction, while the detection effect of other pesticides was not affected by time. like Figure 5As shown, the fluorescence intensity of fluorescent probe L-3 and glyphosate at different concentrations and the fluorescence intensity of fluorescent probe L-3 and 2,4-drop propionic acid were compared. When the concentration of glyphosate was 110 uM, the fluorescence intensity reached the highest value, and the detection effect of other pesticides was not affected by the concentration. like Figure 6 As shown, the fluorescence intensity of L-3 after glyphosate extraction from different soils is compared with the fluorescence intensity of the probe alone without pesticides. It can be seen that the fluorescent probe can function normally in different complex soils. like Figure 7 As shown, the color comparison between probe L-3 and glyphosate in methanol under normal sunlight shows that the fluorescent probe appears colorless and transparent after reacting with the pesticide glyphosate, while the others appear pale yellow. like Figure 8 The image shown is a color comparison of the test strips of fluorescent probe L-3 after different pesticides were added, under normal sunlight.

[0023] Example 5: A solvent-tunable rapid detection method with high specificity and selectivity for 2,4-D propionic acid pesticides. This detection method is for the detection of 2,4-D propionic acid residues in fresh leaves and includes the following steps: S1. Dissolve L-3 in dimethyl sulfoxide to prepare an L-3 solution with a molar concentration of 10 uM; dissolve 2,4-drops of propionic acid in ultrapure water to prepare a 2,4-drops of propionic acid solution with a molar concentration of 40 mM. S2. Randomly select leaves from different farmlands and spray them with 2,4-drop propionic acid solution until the pesticide penetrates. At the same time, weigh the same mass of fresh leaves that have not been sprayed with pesticide as a parallel control. The interval between spraying the 2,4-drop propionic acid solution and the L-3 solution is 3-5 minutes. S3. Compare the effects of spraying the same fresh leaf with fluorescent light and normal sunlight before and after spraying, and compare the effects before and after spraying. S4. Spray the leaves with a solution of 2,4-propionic acid dissolved in methanol:water = 0.05:0.95 and L-3 dissolved in dimethyl sulfoxide, and compare the fluorescence at 365 nm. Add 50 μL of L-3 solution, 50 μL of 2,4-drop propionic acid solution, and 3.9 mL of a mixture of methanol and water (methanol:water = 0.05:0.95) sequentially to a centrifuge tube. Immediately perform fluorescence testing with the following parameters: excitation slit width 10 nm, emission slit width 10 nm, and excitation wavelength 360 nm. The final detection concentration of L-3 solution is 10 μM, and the final detection concentration range of 2,4-drop propionic acid solution is 0-150 μM.

[0024] like Figure 9As shown, when the fluorescent probe L-3 was reacted with different pesticides, only 2,4-drop propionic acid showed significant fluorescence enhancement, indicating that the L-3 prepared in this invention can detect 2,4-drop propionic acid with high specificity. like Figure 10 As shown, the fluorescence intensity of fluorescent probe L-3 and 2,4-D propionic acid at different concentrations was compared with that of fluorescent probe L-3 and the pesticide glyphosate. When the concentration of 2,4-D propionic acid was 40 uM, the fluorescence intensity reached the highest value, and the detection effect of other pesticides was not affected by the concentration. like Figure 11 As shown, the fluorescent probe L-3 was reacted with 2,4-drops of propionic acid for 0-60 minutes, and fluorescence tests were performed at different time intervals. The fluorescence intensity of the fluorescent probe reached a plateau at 1 minute of reaction, while the detection effect of other pesticides was not affected by time. like Figure 12 The above is a color comparison between probe L-3 under normal sunlight and glyphosate under methanol. The fluorescent probe appears colorless and transparent after reacting with the pesticide glyphosate, while the other pesticides appear yellow. like Figure 13 The image shows a color comparison of L-3 sprayed in a methanol-water mixture (methanol:water = 0.05:0.95) on eight different leaves under UV and normal sunlight, and under UV light after spraying with probe L-3. It can be seen that after spraying the pesticide 2,4-propionic acid, no fluorescence or special color is observed under sunlight and UV (365nm), but yellow fluorescence is observed after spraying with the probe. like Figure 15 As shown in the figure, soil extract was added to a high aqueous phase or methanol system of L-3, and the change in fluorescence intensity was detected. As can be seen from the figure, there is a very large difference in fluorescence intensity between soil extract with added pesticide and soil extract without added pesticide. like Figure 16 As shown in the figure, different actual samples such as wheat, soybeans, seawater, and lake water were selected, and different concentrations of glyphosate and 2,4-drop propionic acid were added using the standard addition method. The spiked recovery rate was detected using probe L-3. As can be seen from the figure, under different spiked conditions, the recovery rate of each sample remained in the range of 91.3%-116%, indicating that the detection method of the present invention has extremely high accuracy and is not affected by complex sample matrices, and can achieve accurate quantitative analysis of actual samples.

[0025] Example 6: A solvent-tunable rapid detection device with high specificity and selectivity for glyphosate and 2,4-drop propionic acid pesticides. This device is a fluorescent test strip, and the preparation of the fluorescent test strip includes the following steps: S1. Cut neutral filter paper into circular test strips with a diameter of 8-15 mm, immerse them in the prepared L-3 solution for 2-5 minutes and dry them at room temperature to obtain fluorescent test strips; S2. Add different concentrations of the pesticide to be tested to the fluorescent test paper and observe the fluorescence response of the test paper under normal sunlight. S3. Continue to add glyphosate solutions of different concentrations prepared in step S2 to the test paper, and observe the fluorescence response of the test paper under normal sunlight.

[0026] like Figure 14 As shown in the figure, the test paper soaked with probe L-3 is used as the detection device. After 10 different pesticides are added to it, the fluorescence change is observed. As can be seen from the figure, the test paper with 2,4-drops of pesticide propionic acid added emits strong yellow fluorescence.

[0027] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make inventive modifications to this embodiment as needed, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A solvent-tunable rapid detection method for glyphosate and 2,4-D propionic acid pesticides with high specificity and selectivity, characterized in that, Detection is performed using a fluorescent probe, which is prepared by the following steps: S1. Weigh aniline and p-hydroxybenzaldehyde, dissolve them together in glacial acetic acid, and stir the reaction at room temperature for 1 hour. Then, slowly add ammonium acetate and bibenzoyl to the reaction system, gradually raise the temperature to 120°C and continue the reaction for 20 hours. During this period, monitor the reaction progress with TLC until the raw materials are completely converted. After the reaction is completed, slowly add glacial sodium peroxide solution to the reaction system to adjust the pH to neutral. After filtration and washing, obtain a light pink solid L-1 and dry it. S2. The obtained L-1 was mixed with urotropine in a molar ratio and dissolved in trifluoroacetic acid. The mixture was heated to 110°C and stirred for 11 hours. The reaction endpoint was confirmed by TLC. After the reaction was completed, the reaction system was cooled to room temperature. Then, glacial sodium bicarbonate solution was slowly added until no bubbles were generated. After post-treatment purification, yellow-green granular powder L-2 was obtained. S3. Dissolve L-2 and 2-hydrazinopyrazine together in ultra-dry ethanol, add one drop of glacial acetic acid as a catalyst, and reflux at 95°C overnight. During the reaction, the system gradually changes from yellow to orange-yellow, accompanied by the precipitation of solid. The reaction is confirmed to be complete by TLC monitoring. After concentrating the reaction solution by rotary evaporation, the obtained solid is washed in ice-cold methanol and stirred for 12 hours. Finally, after filtration and drying, the orange-yellow solid product L-3 is obtained, which is the fluorescent probe. 。 2. The method for rapid detection of glyphosate and 2,4-D propionic acid pesticides with high specificity and selectivity that can be controlled by a solvent, as described in claim 1, is characterized in that: In S1, the amount of glacial acetic acid is 15 ml, and the molar ratio of aniline, p-hydroxybenzaldehyde, ammonium acetate and bibenzoyl is 1:1:1:

1.

3. The method for rapid detection of glyphosate and 2,4-D propionic acid pesticides with high specificity and selectivity that can be controlled by a solvent, as described in claim 1, is characterized in that: In S2, the trifluoroacetic acid is 30 ml, the purification is column chromatography, and the volume ratio of the elution phase is petroleum ether: ethyl acetate = 10:

1. The molar ratio of L-1 to hexamethylenetetramine is 1:

4.

4. The method for rapid detection of glyphosate and 2,4-D propionic acid pesticides with high specificity and selectivity that can be controlled by a solvent, as described in claim 1, is characterized in that: The reactions S1-S3 were all carried out under nitrogen protection.

5. A solvent-tunable rapid detection method for glyphosate with high specificity and selectivity, employing the fluorescent probe according to any one of claims 1-4, characterized in that, The detection method is colorimetric detection, which includes the following steps: S1. Dissolve glyphosate in ultrapure water to prepare a pesticide dilution solution, and dissolve L-3 in chromatographic grade dimethyl sulfoxide to prepare an L-3 solution; S2. Add methanol, L-3 solution, and pesticide dilution solution to the centrifuge tube in sequence, and control the volume ratio of methanol, L-3 solution, and pesticide dilution solution to be 3900uL:50uL:50uL. Then the fluorescence test can be performed.

6. The method for rapid detection of glyphosate with high specificity and selectivity that can be controlled by a solvent, as described in claim 5, is characterized in that: In S1, the molar concentration of the L-3 solution is 10 μM; the molar concentration of the glyphosate solution is 40 mM; in S2, the interval between spraying the glyphosate solution and the L-3 solution is 15-60 minutes.

7. A solvent-tunable rapid detection method for 2,4-drop propionic acid pesticides with high specificity and selectivity, employing the fluorescent probe as described in any one of claims 1-4, characterized in that, The detection method is colorimetric detection, which includes the following steps: S1. Dissolve 2,4-drops of propionic acid in methanol to prepare a pesticide dilution solution; dissolve L-3 in chromatographic grade dimethyl sulfoxide to prepare an L-3 solution. S2. Add L-3 solution, pesticide dilution solution, and methanol sequentially to a centrifuge tube, and control the volume ratio of methanol, L-3 solution, and pesticide dilution solution to be 3900uL:50uL:50uL, and then perform fluorescence testing.

8. A solvent-tunable rapid detection device for glyphosate and 2,4-drop propionic acid pesticides with high specificity and selectivity, characterized in that: The device is a fluorescent test strip.

9. The solvent-tunable rapid detection device for glyphosate and 2,4-drop propionic acid pesticides with high specificity and selectivity according to claim 8, characterized in that, The preparation of the fluorescent test strip includes the following steps: S1. Cut neutral filter paper into circular test papers with a diameter of 8-15 mm, immerse them in the prepared L-3 solution and dry them at room temperature to obtain fluorescent test paper; S2. Add different concentrations of the pesticide to be tested to the fluorescent test paper and observe the fluorescence response of the test paper under normal sunlight. S3. Continue to add glyphosate solutions of different concentrations prepared in step S2 to the test paper, and observe the fluorescence response of the test paper under normal sunlight.

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