Method for detecting pesticide by using colorimetric sensing array based on copper-based MOF composite material

Abstract

The invention discloses a method for detecting pesticide based on a colorimetric sensing array of a copper-based MOF composite material, and relates to the technical field of pesticide detection.The method comprises the steps that a Co, Zn and Cu-MOF (VB2) composite nano-enzyme material with peroxidase-like activity and laccase-like activity is prepared; before and after a pesticide analyte to be detected is added, the peroxidase-like activity and laccase-like activity of the Co, Zn and Cu-MOF (VB2) composite nano-enzyme material catalyze different substrates in a neutral environment, so that catalytic products have different colorimetric responses to detect the pesticide analyte to be detected. The method can be used for simultaneously distinguishing and detecting five pesticides including carbendazim, pendimethalin, thiophanate-methyl, triadimefon and acetamiprid, and has the advantages of simplicity and convenience in operation and high detection speed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pesticide detection, and particularly relates to a method for detecting pesticides based on a colorimetric sensing array of a copper-based MOF composite material. BACKGROUND

[0002] Pesticide residues in tobacco not only affect the quality and safety of tobacco leaves, but also are a key indicator for evaluating green and high-quality tobacco. This problem is particularly important for international tobacco producers and is related to the health protection of consumers. Therefore, it is necessary to strengthen the supervision of pesticide residues in tobacco. At present, the analysis of pesticide residues in China mainly focuses on fruits, vegetables and grains, etc. Compared with the above, the analysis method for pesticide residues in tobacco and its products is not mature, and the existing research mainly focuses on organophosphorus, organochlorine, pyrethroid and amide pesticides. In order to improve the maximum residue limit of pesticides in tobacco and tobacco products, promote safe planting of tobacco leaves, and protect the ecological environment and human health, it is urgent to develop an efficient and reliable pesticide residue analysis method specially designed for tobacco.

[0003] At present, the methods for detecting pesticide residues mainly include two categories: biochemical determination method and chromatographic detection technology. The biochemical determination method requires fewer purification steps and has relatively fast detection speed. The chromatographic detection technology mainly includes gas chromatography and high performance liquid chromatography. Although these methods have high sensitivity and accuracy, they rely on expensive equipment and professional operators, which limits the on-site rapid analysis.

[0004] In view of the above problems, it is necessary to study a method for detecting pesticides based on a colorimetric sensing array of a copper-based MOF composite material to solve the above technical problems. SUMMARY

[0005] The main purpose of the present application is to provide a method for detecting pesticides based on a colorimetric sensing array of a copper-based MOF composite material, which aims to solve the technical problem that the original pesticide analysis method cannot detect multiple pesticides at the same time.

[0006] To achieve the above purpose, the present application provides the following technical scheme: The present application provides a method for detecting pesticides based on a colorimetric sensing array of a copper-based MOF composite material, which comprises the following steps: S1, preparing a Co, Zn@Cu-MOF(V B2 ) composite nanometer enzyme material with peroxidase-like activity and laccase-like activity; S2, adding the Co, Zn@Cu-MOF(V B2The peroxidase-like and laccase-like activities of the composite nanozyme material catalyze different substrates under neutral conditions, resulting in different colorimetric responses of the catalytic products for the detection of pesticide analytes.

[0007] Using the above method, this application has developed a vitamin B2 (riboflavin)-derived metal-organic framework (MOF) composite material, which is Co,Zn@Cu-MOF(V B2 The material exhibits stable peroxidase-like (POD) and laccase-like (LAC) activities. In the presence of H₂O₂, it catalyzes different substrates (TMB, ABTS, and DAB) to produce blue, green, and brown ions, respectively, and in the presence of 4-AP and light, it catalyzes 2,4-DP to produce a red ion. Based on the dual-enzyme mimicry activity of this material, a colorimetric sensor array was developed for the differentiation and detection of five pesticides: carbendazim (CBZ), pendimethalin (PEN), thiophanate-methyl (MT), triadimefon (TDF), and acetamiprid (ACE). The results were statistically analyzed using absorbance measurement, hierarchical cluster analysis (HCA), and linear discriminant analysis (LDA) to achieve rapid detection and multi-target identification.

[0008] Preferably, in S1, Co,Zn@Cu-MOF(V B2 The preparation methods of composite nanoenzyme materials include: S11, V B2 Dissolve in methanol and stir to obtain solution A; S12. Dissolve Zn(NO3)2·6H2O, CuCl2 and CoCl2 in methanol and stir to obtain solution B; S13. Mix and stir solutions A and B to obtain a mixture; microwave digest the mixture to obtain the reactants. S14. After washing and drying the reactants, Co,Zn@Cu-MOF(V) is obtained. B2 Composite nanoenzyme materials.

[0009] Preferably, V in S11 B2 The mass-to-volume ratio of methanol is 0.01-0.05 g / mL; the stirring time is 5-30 min.

[0010] Preferably, the total mass ratio of Zn(NO3)2·6H2O, CuCl2 and CoCl2 in S12 to the mass-volume ratio of methanol is 0.01-0.05 g / mL; the ratio of Zn(NO3)2·6H2O:CuCl2:CoCl2 is 2:1:1; and the stirring time is 5-30 min.

[0011] Preferably, the volume ratio of A liquid and B liquid in S13 is 0.5-2:1, and the stirring time is 5-30 min; the microwave digestion is reacted at 100-200°C for 2-8h.

[0012] Preferably, the washing in S14 is washed with ethanol and distilled water alternately for 2-6 times; and the drying is vacuum dried at 40-70°C for 8-15h.

[0013] Preferably, the substrate catalyzed by the peroxidase-like activity in S2 is TMB, ABTS and DAB; and the substrate catalyzed by the laccase-like activity is 4-AP.

[0014] Preferably, the step of developing the substrate TMB, ABTS and DAB catalyzed by the peroxidase-like activity includes: mixing Co,Zn@Cu-MOF(V B2 ) and different pesticides respectively, and incubating at room temperature; then adding TMB containing H2O2, ABTS containing H2O2 and DAB containing H2O2 into each pesticide, and diluting to the final volume; and measuring the absorbance at 654 nm, 415 nm and 450 nm respectively. The step of developing the substrate 2,4-DP catalyzed by the laccase-like activity includes: mixing Co,Zn@Cu-MOF(V B2 ) and different pesticides respectively, and adding the mixture of 2,4-DP, Tris-HCl buffer solution containing pH 7.0 and 4-AP into different pesticides containing Co,Zn@Cu-MOF(V B2 ), diluting to the final volume with deionized water, and then measuring the absorbance at 505 nm after catalyzing under LED light irradiation for 5-30 min. Preferably, the different pesticides are carbendazim (CBZ), pendimethalin (PEN), thiophanate-methyl (MT), trifloxystrobin (TDF) and acetamiprid (ACE) with a concentration of 0.3-0.5 μg / mL; the volume ratio of Co,Zn@Cu-MOF(V B2 ) and carbendazim, pendimethalin, thiophanate-methyl, trifloxystrobin and acetamiprid is 1:1 respectively; The volume ratio of H2O2 and TMB, ABTS and DAB is 1:1; the concentration of Co,Zn@Cu-MOF(V B2 ) is 10-30 μg / mL; the concentration of H2O2 is 30-80 μL; the concentration of TMB is 3-10 mM, the concentration of ABTS is 5-20 mM and the concentration of DAB is 30-80 mM; 2,4-DP, Tris-HCl buffer and 4-AP are in a volume ratio of 1:0.2-1:1; the concentrations of 2,4-DP and 4-AP are both 10-30 mM; the total volume of 2,4-DP, Tris-HCl buffer and 4-AP is respectively 2, 4-DP, Tris-HCl buffer and 4-AP, Co, Zn@Cu-MOF(V B2 ) and carbendazim (CBZ), pendimethalin (PEN), thiophanate-methyl (MT), trifloxystrobin (TDF) and acetamiprid (ACE) are all in a volume ratio of 2-5:1.

[0015] Preferably, when the absorbance is detected, the mass concentration ratio of H2O2 and TMB is 10:1; the mass concentration ratio of H2O2 and ABTS is 5:2; the mass concentration ratio of H2O2 and DAB is 10:1; and the mass concentration ratio of 4-AP and 2,4-DP is 1:1. After the detection is completed, a column chart is first drawn according to A / A0 (A represents the absorbance of the pesticide, and A0 represents the absorbance of the blank) obtained by the absorbance detection, and then the results of A / A0 are clustered and distinguished by LDA, a heat map and HCA.

[0016] The present application has the following beneficial effects: 1. The present application prepares a Co,Zn@Cu-MOF(V B2 ) composite nanoenzyme material, which exhibits POD activity and LAC activity under neutral pH conditions, wherein the LAC activity is activated by light response. B2 In addition, the present application successfully uses the method to distinguish tobacco samples produced from different regions, which has application value for pesticide monitoring.

[0017] 2. The method provided by the present application can simultaneously detect and distinguish multiple pesticides, which is not only simple to operate, but also fast in detection. BRIEF DESCRIPTION OF DRAWINGS Figure 1 (a) is a scanning electron microscope image of Co,Zn@Cu-MOF(V B2 ) prepared by the present application, and (b) is a UV-visible spectrum of Co,Zn@Cu-MOF(V B2 ) catalyzing various substrates; Figure 2 (a) is the color development result of the colorimetric sensor array for detecting five pesticides according to the present application, and (b) is the absorbance ratio of the five pesticides with respect to substrates TMB, ABTS, DAB and 2,4-DP; Figure 3LDA score plot of the sensing array for distinguishing five target pesticide analytes (a), HCA dendrogram of five target analytes classification (b), heat map of five pesticides for four substrates (c); Figure 4 LDA score plot of the sensing array for distinguishing four tobacco leaves (a), HCA dendrogram of four tobacco leaves classification (b); Figure 5 Flow chart of the method for detecting pesticides based on colorimetric sensing array of copper-based MOF composite material of the present application. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.

[0019] Embodiment 1 A method for detecting pesticides based on colorimetric sensing array of copper-based MOF composite material, comprising the following steps: 1.1 Synthesis of Co,Zn@Cu-MOF(V B2 ) composite nanoscale enzyme material: 0.3 g V B2 was dissolved in 20 mL of methanol and stirred for 30 min to obtain solution A; 0.3 g Zn(NO3)2·6H2O, 0.2 g CuCl2 and 0.2 g CoCl2 were dissolved in 20 mL of methanol and stirred for 30 min to obtain solution B; The above-mentioned solution A and solution B were mixed and stirred for 30 min, and the mixture was transferred to a microwave digestion tank and reacted at 200°C for 8 h; The obtained material was washed with ethanol and distilled water for three times, and then vacuum dried at 55°C for 12 h; the dried material was stored at 4°C and resuspended in distilled water before use.

[0020] The obtained material was characterized under a scanning electron microscope (SEM) to observe the morphology of the material. It can be observed that the material has a loose and porous network structure (Fig. Figure 1 a). Subsequently, the peroxidase-like activity and laccase-like activity of the material were verified using four substrates of TMB, ABTS, DAB and 2,4-DP (Fig. Figure 1 b). 1.2 Construction of colorimetric sensing array: 1.2.1 The POD-like activity of Co,Zn@Cu-MOF(V B2 ) was regarded as three colorimetric channels of TMB, ABTS and DAB. 50 μL of 30 μg / mL Co,Zn@Cu-MOF(V B2Five different pesticides (CBZ, PEN, MT, TDF, and ACE) at a concentration of 0.5 μg / mL were mixed and incubated at room temperature. Then, 80 μL of TMB (10 mM) containing 80 μL H2O2, 80 μL of ABTS (20 mM) containing 80 μL H2O2, and 80 μL of DAB (80 mM) containing 80 μL H2O2 were added, and diluted to a final volume of 200 μL. Their absorbances were measured at 654 nm, 415 nm, and 450 nm.

[0021] 1.2.2 Co,Zn@Cu-MOF(V B2 The LAC-like activity of ) was considered as another colorimetric channel. A mixture containing 2,4-DP (150 μL, 30 mM), Tris-HCl buffer (80 μL, pH 7.0), and 4-AP (150 μL, 30 mM) was added to Co,Zn@Cu-MOF(V B2 The mixture of five pesticides (50 μL, 30 μg / mL) and 50 μL each of CBZ, PEN, MT, TDF and ACE (all at a concentration of 0.5 μg / mL) was diluted with deionized water to a final volume of 300 μL. After catalysis under LED light for 30 minutes, the absorbance was measured at 505 nm.

[0022] 1.2.3 Each sample was repeated 5 times to form a 4 × 5 × 5 data matrix (4 channels × 5 pesticide analytes × 5 replicates). Observe the color changes of the solutions and record their absorbance ( Figure 2 a).

[0023] 1.2.4 Calculate the absorbance ratio (A / A0, where A represents the absorbance of the experimental group and A0 represents the absorbance of the blank group) and then... Figure 2 b) Import the data into Origin software for further analysis, using Linear Discriminant Analysis (LDA), heatmaps, and Hierarchical Cluster Analysis (HCA). Figure 3 The absorbance ratios of the five pesticides to the blank are shown in Table 1. Table 1. Absorbance ratios of five pesticides to the blank control.

[0024] Experimental Example 1 The tobacco samples were detected by extracting the pesticides from the tobacco samples. The extraction process included: 10.0 g of each of the four tobacco leaves was weighed and then placed in four separate 50 mL centrifuge tubes with lids, 20 mL of water was added and stirred. Then, 20 mL of acetonitrile was added to extract the pesticides from the four tobacco leaves. Subsequently, 8 g of anhydrous magnesium sulfate, 3 g of sodium chloride, 3 g of sodium citrate, and 2 g of citric acid were added to remove water from the sample. Finally, the filtrate was obtained by filtering out the residue and collecting the upper acetonitrile filtrate to obtain the sample to be tested.

[0025] The four tobacco samples to be tested were used as new target objects, and the colorimetric sensor array in Example 1 was used to distinguish and detect them. The four extracts were added to the 96-well plate with Co, Zn@Cu-MOF (V B2 ) (50 μL, 30 μg / mL) added in advance, four substrates (TMB, ABTS, DAB, 2,4-DP) were added accordingly, and the reaction was carried out under the corresponding conditions (the catalytic reactions of TMB, ABTS, and DAB were carried out at room temperature under neutral pH conditions; the catalytic reaction of 2,4-DP was carried out at room temperature under neutral pH and LED light conditions). Each sample was repeated 5 times to form a 4 × 4 × 5 data matrix (4 channels × 4 pesticide analytes × 5 repetitions). Then, the absorbance was measured and the data was further analyzed by linear discriminant analysis (LDA) and hierarchical cluster analysis (HCA) Figure 4 a,b). The absorbance ratio of the four tobacco samples to the blank is shown in Table 2.

[0026] Table 2. Absorbance ratio of the four tobacco samples to the blank

[0027] The four tobacco samples to be tested were used as new target objects, and the colorimetric sensor array in Example 1 was used to distinguish and detect them. The four extracts were added to the 96-well plate with Co, Zn@Cu-MOF (V Figure 4 c,d). The absorbance ratio of the binary mixture of the four tobacco samples to the blank is shown in Table 3.

[0028] Table 3. Absorbance ratio of the binary mixture of the four tobacco samples to the blank

[0029] Example 2 A method for detecting pesticides based on a colorimetric sensor array of copper-based MOF composite material, comprising the following steps: 2.1 Synthesis of Co, Zn@Cu-MOF (V B2 ) composite nanenzyme material: 0.05 g V B2 Dissolved in 5 mL methanol and stirred for 5 min to obtain solution A; 0.05 g Zn(NO3)2·6H2O, 0.01 g CuCl2and 0.01 g CoCl2were dissolved in 5 mL methanol and stirred for 5 min to obtain solution B; The above solution A and B were mixed and stirred for 5 min, and the mixture was transferred to a microwave digestion tank and reacted at 100°C for 2 h; The obtained material was washed with ethanol and distilled water for six times, and then vacuum dried at 40°C for 15 h; the dried material was stored at 4°C and resuspended in distilled water before use.

[0030] The obtained material was characterized under scanning electron microscope (SEM) to observe the morphology of the material. It can be observed that the material presents a loose and porous network structure. Subsequently, the peroxidase-like activity and laccase-like activity of the material were verified with four substrates of TMB, ABTS, DAB and 2,4-DP, respectively. 2.2 Construction of colorimetric sensing array: 2.2.1 The POD-like activity of Co,Zn@Cu-MOF(V B2 ) was regarded as three colorimetric channels of TMB, ABTS and DAB. 30 μL, 20 μg / mL of Co,Zn@Cu-MOF(V B2 ) and 30 μL of five different pesticides of CBZ, PEN, MT, TDF and ACE with a concentration of 0.4 μg / mL were mixed and incubated at room temperature. Subsequently, TMB (50 μL, 7 mM) containing 50 μL H2O2(concentration 50 mM), ABTS (50 μL, 10 mM) containing H2O2(50 μL, 50 mM) and DAB (50 μL, 50 mM) containing H2O2(50 μL, 50 mM) were added, respectively, and diluted to a final volume of 200 μL. Their absorbance was measured at 654 nm, 415 nm and 450 nm, respectively.

[0031] 2.2.2 The LAC-like activity of Co,Zn@Cu-MOF(V B2 ) was regarded as another colorimetric channel. The mixture containing 2,4-DP (100 μL, 20 mM), Tris-HCl buffer (50 μL, pH 7.0) and 4-AP (100 μL, 20 mM) was added to Co,Zn@Cu-MOF(V B2The mixture of five pesticides (30 μL, 20 μg / mL) and 30 μL each of CBZ, PEN, MT, TDF and ACE (all at a concentration of 0.4 μg / mL) was diluted with deionized water to a final volume of 300 μL. After catalysis under LED light for 20 minutes, the absorbance was measured at 505 nm.

[0032] 2.2.3 Each sample was repeated 5 times to form a 4 × 5 × 5 data matrix (4 channels × 5 pesticide analytes × 5 replicates). Observe the color changes of the solutions and record their absorbance.

[0033] 2.2.4 The absorbance was calculated as a ratio (A / A0, where A represents the absorbance of the experimental group and A0 represents the absorbance of the blank group), and imported into Origin software for data analysis. The data was further analyzed using linear discriminant analysis (LDA), heatmaps, and hierarchical cluster analysis (HCA).

[0034] Example 3 like Figure 5 As shown, a method for detecting pesticides using a colorimetric sensor array based on copper-based MOF composite materials includes the following steps: 3.1 Synthesis of Co,Zn@Cu-MOF(V B2 Composite nanoenzyme materials: 0.2g V B2 Dissolve in 6 mL of methanol and stir for 20 min to obtain solution A; Dissolve 0.16 g Zn(NO3)2·6H2O, 0.08 g CuCl2 and 0.08 g CoCl2 in 10 mL methanol and stir for 5 min to obtain solution B; Mix the above solutions A and B and stir for 15 minutes. Transfer the mixture to a microwave digestion vessel and react at 150°C for 5 hours. The obtained material was washed twice with ethanol and distilled water, and then vacuum dried at 60°C for 10 h. The dried material was stored at 4°C and resuspended in distilled water before use.

[0035] The obtained material was characterized using a scanning electron microscope (SEM) to observe its morphology. A loose, porous network structure was observed. Subsequently, the peroxidase-like and laccase-like activities of the material were verified using four substrates: TMB, ABTS, DAB, and 2,4-DP. 3.2 Constructing a colorimetric sensor array: 3.2.1 Co,Zn@Cu-MOF(V B2POD-like activity of Co,Zn@Cu-MOF(V B2 ) was considered as three colorimetric channels of TMB, ABTS, DAB. 10 μL, 10 μg / mL of Co,Zn@Cu-MOF(V B2 ) and 10 μL of each of the five different pesticides CBZ, PEN, MT, TDF, ACE with a concentration of 0.3 μg / mL were mixed and incubated at room temperature. Subsequently, 30 μL of H2O2(concentration 30 mM) was added to TMB (30 μL, 3 mM), ABTS (30 μL, 5 mM) and DAB (30 μL, 30 mM) containing H2O2(30 μL, 30 mM), respectively, and diluted to a final volume of 200 μL. Their absorbance was measured at 654 nm, 415 nm and 450 nm, respectively.

[0036] 3.2.2 The LAC-like activity of Co,Zn@Cu-MOF(V B2 ) was considered as another colorimetric channel. A mixture containing 2,4-DP (80 μL, 10 mM), Tris-HCl buffer (30 μL, pH 7.0) and 4-AP (80 μL, 10 mM) was added to Co,Zn@Cu-MOF(V B2 ) (10 μL, 10 μg / mL) and 10 μL of each of the five pesticides CBZ, PEN, MT, TDF, ACE with a concentration of 0.3 μg / mL, respectively, were mixed and diluted with deionized water to a final volume of 300 μL, respectively, and then the absorbance was measured at 505 nm after catalyzing for 5 minutes under LED light irradiation.

[0037] 3.2.3 Each sample was repeated 5 times, forming a 4 × 5 × 5 data matrix (4 channels × 5 pesticide analytes × 5 repetitions). The color change of the solution was observed and their absorbance was recorded.

[0038] 3.2.4 The absorbance was calculated by ratio (A / A0, A represents the absorbance of the experimental group, A0 represents the absorbance of the blank group), and imported into Origin software for data analysis. The data was further analyzed by linear discriminant analysis (LDA), heat map and hierarchical cluster analysis (HCA).

[0039] The above detailed description of the application is only exemplary, and the application is not limited to the specific embodiments described above. Any equivalent modifications or substitutions made by those skilled in the art to the application are also within the scope of the application, and equivalent transformations, modifications, improvements, etc. made without departing from the spirit and principles of the application should be covered within the scope of the application.

Claims

1. A method for detecting pesticides using a colorimetric sensor array based on copper-based MOF composite materials, characterized in that, Includes the following steps: S1. Preparation of Co,Zn@Cu-MOF(V) with peroxidase-like and laccase-like activities. B2 Composite nanoenzyme materials; S2. By measuring the Co,Zn@Cu-MOF(V) analyte before and after the addition of the pesticide analyte, the concentration of Co,Zn@Cu-MOF(V) was determined. B2 The peroxidase-like and laccase-like activities of the composite nanozyme material catalyze different substrates under neutral conditions, resulting in different colorimetric responses of the catalytic products for the detection of pesticide analytes.

2. The method for detecting pesticides using a colorimetric sensor array based on copper-based MOF composite materials as described in claim 1, characterized in that, S1 contains Co,Zn@Cu-MOF(V) B2 The preparation methods of composite nanoenzyme materials include: S11, V B2 Dissolve in methanol and stir to obtain solution A; S12. Dissolve Zn(NO3)2·6H2O, CuCl2 and CoCl2 in methanol and stir to obtain solution B; S13. Mix and stir solutions A and B to obtain a mixture; microwave digest the mixture to obtain the reactants. S14. After washing and drying the reactants, Co,Zn@Cu-MOF(V) is obtained. B2 Composite nanoenzyme materials.

3. The method for detecting pesticides using a colorimetric sensor array based on copper-based MOF composite materials as described in claim 2, characterized in that, S11 in V B2 The mass-to-volume ratio of methanol is 0.01-0.05 g / mL; the stirring time is 5-30 min.

4. The method for detecting pesticides using a colorimetric sensor array based on copper-based MOF composite materials as described in claim 2, characterized in that, The total mass ratio of Zn(NO3)2·6H2O, CuCl2, and CoCl2 to methanol in S12 is 0.01-0.05 g / mL; the ratio of Zn(NO3)2·6H2O:CuCl2:CoCl2 is 2:1:1; and the stirring time is 5-30 min.

5. The method for detecting pesticides using a colorimetric sensor array based on copper-based MOF composite materials as described in claim 2, characterized in that, In S13, the volume ratio of solution A to solution B is 0.5-2:1, and the stirring time is 5-30 min; microwave digestion is carried out at 100-200°C for 2-8 h.

6. The method for detecting pesticides using a colorimetric sensor array based on copper-based MOF composite materials as described in claim 2, characterized in that, In S14, washing involves alternating between ethanol and distilled water 2-6 times; drying involves vacuum drying at 40-70°C for 8-15 hours.

7. The method for detecting pesticides using a colorimetric sensor array based on copper-based MOF composite materials as described in claim 1, characterized in that, The substrates catalyzed by the peroxidase-like activity in S2 are TMB, ABTS, and DAB; the substrate catalyzed by the laccase-like activity is 4-AP.

8. The method for detecting pesticides using a colorimetric sensor array based on copper-based MOF composite materials as described in claim 1, characterized in that, The steps for colorimetric reactions of peroxidase-like catalytic substrates TMB, ABTS, and DAB include: adding Co,Zn@Cu-MOF(V... B2 After mixing with different pesticides, the mixtures were incubated at room temperature. Then, TMB containing H2O2, ABTS containing H2O2, and DAB containing H2O2 were added to each pesticide and diluted to the final volume. The absorbance was measured at 654 nm, 415 nm, and 450 nm, respectively. The steps involved in the colorimetric reaction of the substrate 2,4-DP with laccase-like activity include: Co,Zn@Cu-MOF(V B2 After mixing with different pesticides, the mixture containing 2,4-DP, pH 7.0 Tris-HCl buffer and 4-AP was added to a solution containing Co,Zn@Cu-MOF (V B2 Different pesticides were diluted with deionized water to the final volume, and then catalyzed under LED light for 5-30 minutes before the absorbance was measured at 505 nm.

9. The method for detecting pesticides using a colorimetric sensor array based on copper-based MOF composite materials as described in claim 8, characterized in that, Different pesticides were selected at concentrations of 0.3-0.5 μg / mL, including carbendazim, pendimethalin, thiophanate-methyl, triadimefon, and acetamiprid; Co,Zn@Cu-MOF(V B2 The volume ratios of carbendazim, pendimethalin, thiophanate-methyl, triadimefon, and acetamiprid were all 1:

1. The volume ratios of H2O2 to TMB, ABTS, and DAB are all 1:1; Co,Zn@Cu-MOF(V B2 The concentrations of ) are 10-30 μg / mL; the concentrations of H2O2 are 30-80 μL; the concentrations of TMB are 3-10 mM, ABTS are 5-20 mM, and DAB are 30-80 mM. The volume ratio of 2,4-DP, Tris-HCl buffer, and 4-AP was 1:0.2-1:1; the concentrations of 2,4-DP and 4-AP were both 10-30 mM; the total volume of 2,4-DP, Tris-HCl buffer, and 4-AP was proportional to the volume of Co,Zn@Cu-MOF (V). B2 The volume ratio of carbendazim, pendimethalin, thiophanate-methyl, triadimefon, and acetamiprid is 2-5:

1.

10. The method for detecting pesticides using a colorimetric sensor array based on copper-based MOF composite materials as described in claim 8, characterized in that, During absorbance measurement, the mass ratio of H2O2 to TMB was 10:1; the mass ratio of H2O2 to ABTS was 5:2; the mass ratio of H2O2 to DAB was 10:1; and the mass ratio of 4-AP to 2,4-DP was 1:1.

Images