A rapid fluorescence detection method for organophosphorus compounds based on UiO-66-NH2

Abstract

This invention discloses a rapid fluorescence detection method for organophosphorus compounds based on UiO-66-NH2 and its applications. This method is based on the competitive inhibition principle. Organophosphorus compounds compete with N-ethylmorpholine for binding sites on the UiO-66-NH2 surface. Simultaneously, the bound N-ethylmorpholine disrupts the UiO-66-NH2 structure, releasing the ligand BDC-NH2 and generating fluorescence. This "turn-off" fluorescence detection method features high specificity, high sensitivity, ease of use, and good repeatability. The detection limit for organophosphorus compounds, represented by paraoxonium, is 23.8 ng / mL, the detection range is 0–20 μg / mL, the detection time is 8 min, and various anions in water do not affect the detection results. Furthermore, this method can be applied to the detection of organophosphorus compounds in various water bodies.

Description

Technical Field

[0001] This invention relates to the field of analytical detection technology, and in particular to a highly sensitive fluorescence rapid detection method for organophosphorus compounds based on UiO-66-NH2 material. Background Technology

[0002] In this invention, organophosphorus compounds mainly refer to highly toxic organophosphorus pesticides and organophosphorus nerve agents. These compounds can inhibit the activity of acetylcholinesterase, thus posing a significant hazard to humans and animals. Organophosphorus pesticides are widely used in agricultural production, but large quantities fail to function effectively, remaining on surfaces or entering the environment through water. Due to their high stability and toxicity, these residual organophosphorus pesticides can be ingested by humans, seriously affecting human health. Furthermore, nerve agents are also organophosphorus compounds. To prevent injury or death from ingestion of organophosphorus compounds, in addition to efficient disinfection methods, it is crucial to develop sensitive, simple, and practical detection methods.

[0003] Currently, detection methods for highly toxic organophosphorus pesticides include chromatography, mass spectrometry, and electrochemical methods. However, these methods require expensive equipment and specialized personnel, which greatly limits their ability to enable rapid on-site detection. Simpler and more convenient methods often employ colorimetry or fluorescence, with fluorescence typically offering higher sensitivity. For example, Reza Khaksarinejad used a nanomagnet-silica core-shell coupled OPH enzyme for fluorescence detection of paraoxonium, achieving a detection limit of 5 × 10⁻⁶. -6 μM. This method is simple and easy to use; however, the limited yield and difficulty in long-term preservation of natural enzymes restrict its application.

[0004] Zr-MOF materials are a new class of catalytic materials with high selectivity for organophosphorus compounds, capable of completely decomposing organophosphorus pesticides and organophosphorus nerve agents within minutes. Studies have shown that the mechanism of Zr-MOF decomposition of organophosphorus compounds lies in the specific adsorption of organophosphorus compounds onto the Zr-MOF material surface, followed by the substitution of toxic groups on organophosphorus pesticides with hydroxyl groups. This indicates that Zr-MOFs possess excellent selectivity in decomposing organophosphorus compounds, making them a potential candidate for detecting them. Recently, He et al. prepared a water-stable luminescent MOF (Zr-LMOF) that could detect methyl paraoxon within 5 minutes, with a detection limit of 0.115 μg / kg. They hypothesized that the presence of the -NO2 group causes photogenerated electrons to transfer from Zr-LMOF to methyl paraoxon, resulting in fluorescence quenching.

[0005] In this study, a simple and rapid method for detecting organophosphorus compounds was developed based on competitive reactions. This method can detect paraoxon at concentrations as low as 23.8 ng / mL within 8 minutes, while multiple anions have no effect on the detection. Summary of the Invention

[0006] The purpose of this invention is to provide a rapid fluorescence detection method for organophosphorus compounds based on UiO-66-NH2, which can be used for fluorescence detection of highly toxic organophosphorus pesticides and organophosphorus nerve agents in water.

[0007] The concept of this invention lies in the fact that when organophosphorus compounds are mixed with NES and then added to a UiO-66-NH2 suspension, the organophosphorus compounds and NES compete for Zr on the UiO-66-NH2. 4+ Defect sites, and binding to them, leading to the original Zr 4+ The coordinated ligand BDC-NH2 is released, and this ligand produces fluorescence under ultraviolet excitation. The fluorescence intensity decreases as the concentration of organophosphorus compounds increases, which can be used for the detection of organophosphorus compound concentrations.

[0008] To achieve the above objectives, the present invention provides the following solution:

[0009] A rapid fluorescence detection method for organophosphorus compounds based on UiO-66-NH2 material includes the following steps: mixing an aqueous sample containing organophosphorus compounds with N-ethylmorpholine (NES) to obtain a mixture, then transferring the mixture to a 10 mM Tris suspension of UiO-66-NH2, shaking for 1 min, reacting in a shaker, filtering the resulting suspension through a 0.22 μM filter membrane to obtain a filtrate, placing the filtrate in a quartz dish, and detecting it using a fluorescence spectrometer.

[0010] Preferably, the UiO-66-NH2 crystal size is 100~200nm and the specific surface area is 800~1000 m². 2 / g; the pH of the 10mM Tris buffer is 6~8, with 6.5 being optimal; the concentration of the 10mM Tris suspension of UiO-66-NH2 is 0.5~2mg / mL, with 1.33 mg / mL being optimal, and the volume used is 3~6 mL, with 4 mL being optimal;

[0011] The concentration of NES is 0.3~0.6 mol / L, with an optimal concentration of 0.45 mol / L; the molar ratio of organophosphorus compounds to NES in the water sample is less than or equal to 0.9:1; the volume ratio of NES to 10 mM Tris suspension of UiO-66-NH2 is less than or equal to 1:40.

[0012] The aqueous sample containing the organophosphorus compound was mixed with NES for 1-10 min, with an optimal time of 3 min; and reacted in a shaker for 1-30 min, with an optimal time of 4 min.

[0013] The parameters of the fluorescence spectrometer are set as follows: excitation wavelength is 280~360nm, with an optimal value of 330±5 nm; emission wavelength is 300~600nm; slit width is 5 nm; and electron multiplier tube voltage is 700V.

[0014] Preferably, the organophosphorus compound is a toxic organophosphorus pesticide or organophosphorus chemical agent, including but not limited to methyl parathion, parathion, phorate, and nerve agents.

[0015] Furthermore, the concentration of acetone, acetonitrile, benzene, or dichloromethane in the aqueous sample containing the organophosphorus compound is not higher than 1 mg / mL.

[0016] Furthermore, the concentration of the organophosphorus compounds in the water sample is equal to the concentration of interfering ions F. - CO3 - and PO4 3- The total concentration was more than 20 times higher. Anion Br - Cl - NO3 - SO3 2- SO4 2- AC - and CA 3- It has no effect on this detection; interfering ion F - CO3 - and PO4 3- This method will cause the system to be fluorescently enhanced. It is suitable for the detection of water samples in which the concentration of organophosphorus compounds is more than 20 times the total concentration of interfering ions.

[0017] Preferably, 100 μL of 0.45 mol / L NES is mixed with the phosphorus oxychloride water sample for 3 min, and then the mixture is transferred to a suspension of 1.33 mg / mL UiO-66-NH2 and 10 mM Tris. After shaking for 1 min, the mixture is reacted in a shaker for 4 min, filtered, and then detected. The detection range for phosphorus oxychloride is 1~20 μg / mL, the detection limit is 23.8 ng / mL, and the detection time is 8 min.

[0018] Preferably, the organophosphorus compound is mixed with NES and then added to the UiO-66-NH2 suspension, causing the organophosphorus compound and NES to compete for Zr on UiO-66-NH2. 4+ Defect sites, and with Zr 4+ Defect sites bind, causing the original Zr to bind. 4+The coordinated ligand BDC-NH2 is released, and the fluorescence of BDC-NH2 under UV excitation decreases with increasing organophosphorus compound concentration. The concentration of organophosphorus compound is determined by constructing a linear relationship between fluorescence intensity and organophosphorus compound concentration.

[0019] The beneficial effects of this invention are as follows: Based on the principle of competitive inhibition, this study utilizes organophosphorus compounds to compete with N-ethylmorpholine for binding sites on the UiO-66-NH2 surface, thereby disrupting the UiO-66-NH2 structure, releasing the ligand BDC-NH2, and generating fluorescence. The fluorescence intensity decreases with increasing organophosphorus compound concentration. This "turn-off" fluorescence detection method features high specificity, high sensitivity, ease of use, fast detection speed, and good repeatability. Multiple anions in water do not affect the detection results. Furthermore, it can be applied to the detection of organophosphorus compounds in various water bodies. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a scanning electron microscope image of UiO-66-NH2 used in Example 1;

[0022] UiO-66-NH2 prepared by a and b, and UiO-66-NH2 after use by c and d.

[0023] Figure 2 The X-ray diffraction pattern of UiO-66-NH2 used in Example 1;

[0024] The vertical axis represents the diffraction intensity, and the horizontal axis represents twice the diffraction angle (degrees).

[0025] a. UiO-66-NH2 (simulation calculation), b. UiO-66-NH2 (preparation), c. UiO-66-NH2 (after use).

[0026] Figure 3 The graph shows the changes in fluorescence intensity caused by different concentrations of paraoxygen when the UiO-66-NH2 used in Example 1 detects paraoxygen at a detection time of 8 min.

[0027] The vertical axis represents fluorescence intensity, and the horizontal axis represents wavelength (nanometers).

[0028] Figure 4The graph shows the linear relationship between different concentrations of paraoxygenated phosphorus and fluorescence intensity when the detection time is 8 min, using UiO-66-NH2 to detect paraoxygenated phosphorus.

[0029] The vertical axis represents fluorescence intensity, and the horizontal axis represents concentration (µg / mL).

[0030] Figure 5 The interference diagram of other anions on the detection of paraoxonium using UiO-66-NH2 in Example 1, when the detection time is 8 min;

[0031] The vertical axis represents the percentage of fluorescence intensity, and the horizontal axis represents anions (µg / mL).

[0032] Figure 6 The UiO-66-NH2 used in Example 1 was used to detect phosphorus oxygen. The detection time was 8 minutes, and the detection was repeated every other day.

[0033] The vertical axis represents percentages, and the horizontal axis represents the number of times.

[0034] Figure 7 The UiO-66-NH2 used in Example 1 was used to detect paraoxygenated phosphorus. The detection time was 8 minutes, and the detection effect was shown in the actual water sample. The paraoxygenated phosphorus concentration was 10 μg / mL.

[0035] The vertical axis represents percentages, and the horizontal axis represents: a. distilled water, b. tap water, c. lake water.

[0036] Figure 8 The UiO-66-NH2 used in Example 1 was used to detect paraoxygenated phosphorus. The detection time was 8 minutes, and the detection effect was shown in the actual water sample. The paraoxygenated phosphorus concentration was 15 μg / mL.

[0037] The vertical axis represents percentages, and the horizontal axis represents: a. distilled water, b. tap water, c. lake water. Detailed Implementation

[0038] Embodiments of the present invention provide a rapid fluorescence detection method for detecting paraoxygen and phosphorus in water based on UiO-66-NH2.

[0039] Example 1

[0040] (1) Using 10 mM Tris with a pH of approximately 6.5, and a grain size of approximately 150 nm and a specific surface area of ​​approximately 905 m², 2 A mixture of 1.33 mg / mL UiO-66-NH2 and 10 mM Tris was prepared to form a suspension. The suspension was shaken for 60 seconds to ensure homogeneity. A scanning electron microscope image of the UiO-66-NH2 is shown below. Figure 1The X-ray diffraction pattern of UiO-66-NH2 is shown below. Figure 2 .

[0041] (2) The organophosphorus compound solution is represented by the paraoxon standard solution. The concentration of the paraoxon standard solution is 1000 μg / mL (containing 1 mg / mL acetone). Different volumes of paraoxon standard solution are first mixed with 100 μL of 0.45 mol / L NES for 3 min, and then added to 4 mL of suspension of 1.33 mg / mL UiO-66-NH2 and 10 mM Tris. After shaking for 60 seconds and shaking in a shaker for 4 min, the suspension is filtered through a 0.22 μm filter membrane. About 3 mL of the filtrate is placed in a quartz dish with a width of 1 cm and placed in a fluorescence spectrum for detection.

[0042] (3) The Dongpeng F-380 fluorescence spectrometer was used for detection. The fluorescence spectral conditions were: excitation wavelength 330±5 nm, emission wavelength 300~600 nm, slit width 5 nm, and electron multiplier tube voltage 700 V. The fluorescence produced by different concentrations of para-oxygen phosphorus was detected as follows: Figure 3 As shown, the fluorescence intensity (FL) exhibits a linear relationship with the concentration of paraoxonium (C, μg / mL): FL = 41.91C + 1297.37 (R0). 2 =0.994), indicating that the detection range of this method is 1~20 μg / mL, and the detection limit is 23.8 ng / mL. Figure 4 As shown.

[0043] (4) While detecting paraoxon, add Cl at a concentration of 20 μg / mL. - ,Br - NO3 - SO3 2- SO4 2- AC - CA 3- PO4 3- CO3 - F - Common anions in water bodies, such as Figure 5 As shown, the measured value of Cl added was... - ,Br - NO3 - SO3 2- SO4 2- AC - CA 3- Anions do not affect the fluorescence intensity of the solution, meaning they have no impact on detection; while interfering ions, such as PO4, do not. 3- CO3 - F -It can significantly induce fluorescence enhancement, causing considerable interference with detection, such as... Figure 5 As shown. To avoid the influence of the above ions on the detection, the total concentration of the above ions can be controlled at 1 / 20 of the concentration of paraoxonium to be detected.

[0044] (6) Use the above optimal conditions to test for paraoxon for three consecutive days, such as Figure 6 As can be seen, the fluorescence produced at the same phosphorus oxygen concentration remains essentially unchanged, indicating that this method has good reproducibility.

[0045] (7) The method is the same as above. First, prepare a 10 mM Tris solution with a pH of approximately 6.5 using distilled water, tap water, and lake water. Then, add the above-mentioned paraoxon standard solution to make the paraoxon concentrations in 4 mL of the 1.33 mg / mL UiO-66-NH2 and 10 mM Tris suspensions 10 and 15 μg / mL, respectively. Figure 7 , Figure 8 As shown, the same concentration of CO3 was detected in both lake water and tap water. 2- The fluorescence produced is slightly weaker than that produced in distilled water, but it does not affect normal detection.

Claims

1. A rapid fluorescence detection method for organophosphorus compounds based on UiO-66-NH2 material, characterized in that, A water sample containing organophosphorus compounds was mixed with N-ethylmorpholine (NES) to obtain a mixture. The mixture was then transferred to a 10 mM Tris suspension of UiO-66-NH2. After shaking for 1 min, the mixture was placed in a shaker for reaction. The resulting suspension was filtered through a 0.22 μM filter membrane to obtain a filtrate. The filtrate was placed in a quartz dish and detected by a fluorescence spectrometer. The UiO-66-NH2 crystals have a grain size of 100~200 nm and a specific surface area of ​​800~1000 m². 2 / g; the pH of the 10mM Tris suspension is 6~8; the concentration of the 10mM Tris suspension of UiO-66-NH2 is 0.5~2 mg / mL, and the amount used is 3~6mL; The concentration of NES is 0.3~0.6 mol / L; the molar ratio of organophosphorus compounds to NES in the water sample is less than or equal to 0.9:1; The volume ratio of 10 mM Tris suspension of NES:UiO-66-NH2 is less than or equal to 1:

40.

2. The fluorescence detection method for rapid detection of organophosphorus compounds based on UiO-66-NH2 material according to claim 1, characterized in that, The aqueous sample of the organophosphorus compound was mixed with NES for 1-10 min and reacted in a shaker for 1-30 min.

3. The fluorescence detection method for rapid detection of organophosphorus compounds based on UiO-66-NH2 material according to claim 2, characterized in that, The parameters of the fluorescence spectrometer are set as follows: excitation wavelength of 280~360nm, emission wavelength of 300~600nm, slit width of 5nm, and electron multiplier tube voltage of 700V.

4. The fluorescence detection method for rapid detection of organophosphorus compounds based on UiO-66-NH2 material according to claim 1, characterized in that, The organophosphorus compounds are toxic organophosphorus pesticides and organophosphorus chemical agents, including methyl parathion, parathion, phorate, and nerve agents.

5. The fluorescence detection method for rapid detection of organophosphorus compounds based on UiO-66-NH2 material according to claim 4, characterized in that, The concentration of acetone, acetonitrile, benzene, or dichloromethane in the water sample containing the organophosphorus compound shall not exceed 1 mg / mL.

6. The fluorescence detection method for rapid detection of organophosphorus compounds based on UiO-66-NH2 material according to claim 5, characterized in that, The concentration of organophosphorus compounds in the water sample was the interfering ion F. - CO3 - and PO4 3- The total concentration is more than 20 times higher.

7. The rapid fluorescence detection method for organophosphorus compounds based on UiO-66-NH2 material according to claim 1, characterized in that, 100 μL of 0.45 mol / L NES was mixed with a phosphorus oxychloride water sample for 3 min. The mixture was then transferred to a suspension of 1.33 mg / mL UiO-66-NH2 and 10 mM Tris. After shaking for 1 min, the mixture was reacted in a shaker for 4 min, filtered, and then detected. The detection range for phosphorus oxychloride was 1–20 μg / mL, the detection limit was 23.8 ng / mL, and the detection time was 8 min.

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