A method for preparing a material having peroxidase-like activity and its use in detecting the herbicide propiconazole

Abstract

The application belongs to the technical field of detection, and particularly relates to a preparation method of a material with peroxidase-like activity and application of the material in detection of herbicide propiconazole. ZrOCl2.8H2O is added into a DMF solvent, and then tetracarboxyphenyl porphyrin TCPP is added into the solvent for stirring, acetic acid is added, and then the solution is placed into a polytetrafluoroethylene autoclave for heating, the generated precipitate is collected through centrifugation, and PCN-224 is obtained through vacuum drying; FeCl3 and PCN-224 are added into the DMF for stirring, and then oil bath and centrifugation are performed to obtain Fe@PCN-224. The material with peroxidase-like activity has rich active sites. The material has a low detection limit for detection of herbicide propiconazole.

Description

Technical Field

[0001] This invention relates to the field of detection technology, specifically to a method for preparing a peroxidase-like active material and its application in the detection of the herbicide propiconazole. Background Technology

[0002] Propiconazole (PC) is a fungicide containing a triazole group, widely used to control various fungal diseases in grains, fruits, and vegetables. PC is a class of conazole fungicides with 1,2,4-triazole functional groups. It is a systemic fungicide.

[0003] It works by interfering with ergosterol biosynthesis and inhibiting steroid demethylation. However, PC exposure in the environment can have adverse effects on insects, zooplankton, mammals, fish, and other organisms. Therefore, monitoring PC in food and environmental samples plays a crucial role in the evaluation of food and vegetable quality and safety.

[0004] Liquid chromatography-tandem mass spectrometry (LC-MS), high-performance liquid chromatography-ultraviolet (HPLC-UV) detector, gas chromatography-electron capture detector (GC-Effect Detector), GC-N / Phosphorus detector, GC-Flame ionization detector, and solid-phase desorption ion mobility spectrometry (SPDE-IMS) have been used to estimate the concentration of PC in environmental and food samples. However, their requirements for large solvent volumes, lengthy multiple extractions, skilled technicians, and time-consuming and inconvenient nature limit their application in real-world sample analysis. Therefore, a specially designed method that is convenient and has a short detection time is necessary.

[0005] Fe@PCN-224 is a unique metal-organic framework (MOF) that has recently gained more attention. It possesses abundant active sites and a regular structure, exhibiting strong peroxidase-like activity. It shows potential application prospects in colorimetric sensing for the detection of propiconazole. Summary of the Invention

[0006] Fe@PCN-224, possessing a uniform octahedral structure and abundant active sites, was synthesized via a hydrothermal method. Fe-doped PCN-224 exhibited higher peroxidase-like activity, promoting the efficient catalysis of TMB oxidation by hydrogen peroxide. In the presence of PC, the enzyme-like activity was significantly inhibited, thus establishing a direct colorimetric method for PC detection.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: A material with peroxidase-like activity, the preparation method of which includes the following steps:

[0008] 1) Preparation of PCN-224: ZrOCl2·8H2O was added to DMF solvent, tetracarboxyphenylporphyrin TCPP was added to the solvent and stirred, acetic acid was added, and then the solution was heated in a polytetrafluoroethylene autoclave. The precipitate was collected by centrifugation and vacuum dried to obtain PCN-224.

[0009] 2) Preparation of Fe@PCN-224: FeCl3 and PCN-224 were added to DMF and stirred. Fe@PCN-224 was obtained by oil bath and centrifugation.

[0010] In the above-mentioned material with peroxidase-like activity, in step 1), the mass ratio of ZrOCl2·8H2O to TCPP is 5:1.

[0011] In the above-mentioned material with peroxidase-like activity, in step 1), the stirring time is 10 min.

[0012] In step 1) of the above-mentioned material with peroxidase-like activity, the solution is placed in a polytetrafluoroethylene autoclave and heated for 12 hours at a temperature of 120°C.

[0013] In the above-mentioned material with peroxidase-like activity, the vacuum drying temperature in step 1) is 80°C.

[0014] In the above-mentioned material with peroxidase-like activity, in step 2), the mass ratio of PCN-224 to FeCl3 is 3:4.

[0015] In the above-mentioned material with peroxidase-like activity, in step 2), the oil bath temperature is 120°C and the time is 1 hour.

[0016] In step 2) of the above-mentioned material with peroxidase-like activity, the stirring time is half an hour.

[0017] The above-mentioned material with peroxidase-like activity is used in the detection of the herbicide propiconazole.

[0018] The above application is performed as follows: water is added to a peroxidase-like active material to form a solution, and then propiconazole solution is added dropwise. The concentration of propiconazole is detected by colorimetry based on the absorbance value.

[0019] The beneficial effects of this invention are:

[0020] The peroxidase-like active material described in this invention has abundant active sites and exhibits superior catalytic performance for hydrogen peroxide. Due to its coordination effect with propiconazole, this material has a low detection limit for propiconazole. The detection method described in this invention is convenient, rapid, and facilitates detection. Attached Figure Description

[0021] Figure 1 This is a scanning electron microscope image of Fe@PCN-224 used in Example 1 to study and analyze its morphology.

[0022] Figure 2 These are the full XPS spectra (A) of Fe@PCN-224 and PCN-224 materials in Example 1, and the electron binding energy spectra of Fe 2p (B) and N1s (C).

[0023] Figure 3 This is a comparison chart of enzyme activities of Fe@PCN-224 and PCN-224 materials in Example 1.

[0024] Figure 4 The diagram shows the condition optimization of material Fe@PCN-224 in Example 1, where (A) is the pH optimization diagram and (B) is the temperature optimization diagram.

[0025] Figure 5 This is a linear relationship graph between material Fe@PCN-224 and PC in Example 1. Detailed Implementation

[0026] Example 1: Preparation of a material with peroxidase-like activity

[0027] (I) Preparation of Fe@PCN-224

[0028] 1) Add 125 mg ZrOCl2·8H2O to 50 mL of DMF solvent. Add 25 mg tetracarboxyphenylporphyrin (TCPP) to the solvent and stir for 10 min, then add 12.5 mL of acetic acid. Then, place the solution in a polytetrafluoroethylene autoclave and heat at 120 °C for 12 h. Collect the resulting precipitate by centrifugation and vacuum dry at 80 °C to obtain PCN-224.

[0029] 2) Add 40 mg FeCl3 and 30 mg PCN-224 to 15 mL DMF and stir for half an hour. In a 120 °C oil bath for 1 hour, centrifuge to obtain Fe@PCN-224.

[0030] (II) Testing

[0031] 1. The morphology of Fe@PCN-224 was studied and analyzed using SEM.

[0032] Figure 1 These are scanning electron microscope (SEM) images of Fe@PCN-224 prepared by a hydrothermal method. It exhibits an octahedral structure with an average size of 2.5 μm. (XPS) Figure 2 This demonstrates that Fe@PCN-224 possesses the metal Fe in a variable valence state.

[0033] 2. Evaluation of the peroxidase activity of Fe@PCN-224.

[0034] To verify the peroxidase activity of Fe@PCN-224, we added 50 μL of 5 mM TMB solution, 50 μL of 15% H2O2 solution, and 870 μL of acetate buffer to 30 μL of Fe@PCN-224 (0.4 mg / mL). The mixture was incubated at 30 °C for 10 min, and the UV absorbance at 652 nm was measured. Figure 3 Only when TMB and hydrogen peroxide coexist does Fe@PCN-224 catalyze the oxidation of colorless TMB to blue oxTMB, with the absorbance center located at 652 nm, indicating that Fe@PCN-224 exhibits remarkable peroxidase-like catalytic activity. At 652 nm, the absorbance of the H2O2-TMB system is relatively low. In contrast, the addition of Fe@PCN-224 resulted in a significant change in the solution with characteristic UV-Vis absorption peaks, indicating that Fe@PCN-224 possesses peroxidase-like activity and can catalyze the H2O2-induced oxidation of TMB.

[0035] 3. Optimization of peroxidase activity of Fe@PCN-224.

[0036] like Figure 4 , Figure 4 (A) describes the optimization of the buffer solution's pH. We added 50 μL of 5 mM TMB solution, 50 μL of 15% H2O2 solution, and 870 μL of acetate buffer solutions at different pH values ​​(3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5) to 30 μL of Fe@PCN-224 (concentration 0.4 mg / mL). After incubation at 30°C for 10 min, we measured the UV absorbance at 652 nm. We found that the absorbance was highest at pH 4.0, indicating that the peroxidase activity of Fe@PCN-224 was highest at this pH value. Therefore, the optimal pH is 4.0. Similarly, Figure 4 (B) shows that the temperature was optimized by only changing the incubation temperature. It was found that the absorbance was the highest at 30℃, which proves that the peroxidase activity of Fe@PCN-224 is the highest at this temperature. The optimal temperature is 30℃.

[0037] Example 2 uses Fe@PCN-224 to detect propiconazole.

[0038] 1. Use at a concentration of 0.4 mg / ml -1Fe@PCN-224 was used to detect propiconazole at pH 4.0 and 30°C. Different concentrations of PC solution (0.03-0.9 μM) were added to buffer solutions containing 30 μL Fe@PCN-224 and 840 μL, along with 50 μL TMB (5 mM) and 15% H2O2 solution. The mixture was incubated for 10 min, and the absorbance was measured at 652 nm.

[0039] 2. The detection mechanism mainly involves the coordination of Fe with propiconazole, such as... Figure 5 As the concentration of PC increases, the absorbance signal weakens. Furthermore, there is a linear relationship between absorbance and concentration, such as... Figure 5 As shown. The limit of detection (LOD) is calculated using the formula LOD = 3Sb / S, where Sb is the standard deviation of the blank sample and S is the slope of the linear fit. The calculated LOD is a detection limit of 0.008 μM.

[0040] Example 3: Evaluation of PC concentration detection effect in actual samples

[0041] 1. In the testing process, rapeseed, romaine lettuce, and mushrooms were used as actual samples, as shown in Table 1. Before analysis, the actual samples were pretreated. The samples were crushed, centrifuged, and the supernatant was collected, filtered through a membrane filter, and then diluted 10 times with a buffer solution. Finally, the purified samples were collected for PC analysis. Specifically, the absorbance of the blank sample (i.e., without pesticides) at 652 nm was first measured to obtain A1. Then, PC standard solutions of different concentrations (0.03 μM, 0.45 μM, 0.90 μM) were prepared using the purified supernatant of the actual samples. Add 50 μL of 5 mM TMB solution, 50 μL of 15% H2O2 solution, 30 μL of prepared PC solutions of different concentrations, and 840 μL of acetate buffer solution to 30 μL of Fe@PCN-224 with a concentration of 0.4 mg / mL. Incubate at 30 °C for 10 min, and measure the UV absorbance at 652 nm to obtain A2. Calculate ▲A = A1 - A2. Figure 5 The PC concentration was calculated using the equation. The calculated PC concentrations were: rapeseed (0.034 μM, 0.467 μM, 0.872 μM), lettuce (0.026 μM, 0.400 μM, 0.864 μM), and mushroom (0.034 μM, 0.383 μM, 0.844 μM). Simultaneously, the PC concentrations were measured using fluorescence spectroscopy, yielding: rapeseed (0.029 μM, 0.452 μM, 0.899 μM), lettuce (0.031 μM, 0.449 μM, 0.902 μM), and mushroom (0.028 μM, 0.451 μM, 0.901 μM). The corresponding recoveries and relative standard deviations were calculated.

[0042] Table 1

[0043]

[0044] 2. Fe@PCN-224 exhibits excellent detection performance for PC, with spiked recoveries ranging from 80% to 120%. This indicates that the detection method has good accuracy.

Claims

1. The application of a peroxidase-like active material in the detection of the herbicide propiconazole, characterized in that, The preparation method of the peroxidase-like active material includes the following steps: 1) Preparation of PCN-224: ZrOCl2·8H2O was added to DMF solvent, tetracarboxyphenylporphyrin TCPP was added to the solvent and stirred, acetic acid was added, and then the solution was heated in a polytetrafluoroethylene autoclave. The precipitate was collected by centrifugation and vacuum dried to obtain PCN-224. 2) Preparation of Fe@PCN-224: FeCl3 and PCN-224 were added to DMF and stirred. Fe@PCN-224 was obtained by oil bath and centrifugation.

2. The application of a peroxidase-like active material according to claim 1 in the detection of the herbicide propiconazole, characterized in that, In step 1), the mass ratio of ZrOCl2·8H2O to TCPP is 5:

1.

3. The application of a peroxidase-like active material according to claim 1 in the detection of the herbicide propiconazole, characterized in that, In step 1), the stirring time is 10 minutes.

4. The application of a peroxidase-like active material according to claim 1 in the detection of the herbicide propiconazole, characterized in that, In step 1), the solution is placed in a polytetrafluoroethylene autoclave and heated for 12 hours at a temperature of 120 °C.

5. The application of a peroxidase-like active material according to claim 1 in the detection of the herbicide propiconazole, characterized in that, In step 1), the vacuum drying temperature is 80 ℃.

6. The application of a peroxidase-like active material according to claim 1 in the detection of the herbicide propiconazole, characterized in that, In step 2), the mass ratio of PCN-224 to FeCl3 is 3:

4.

7. The application of a peroxidase-like active material according to claim 1 in the detection of the herbicide propiconazole, characterized in that, In step 2), the oil bath temperature is 120 ℃ and the time is 1 hour.

8. The application of a peroxidase-like active material according to claim 1 in the detection of the herbicide propiconazole, characterized in that, In step 2), the stirring time is half an hour.

9. The application of a peroxidase-like active material according to claim 1 in the detection of the herbicide propiconazole, characterized in that, The method is as follows: water is added to a material with peroxidase-like activity to form a solution, and then propiconazole solution is added dropwise. The concentration of propiconazole is detected by colorimetry based on the absorbance value.

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