Preparation method of a conjugated microporous polymer solid-phase extraction membrane material and its application in detection of benzoylurea pesticides

Abstract

The present invention discloses a preparation method of a conjugated microporous polymer solid-phase extraction membrane material and its application in the detection of benzoylurea pesticides, belonging to the technical field of pesticide detection and analysis. The present invention uses the conjugated microporous polymer solid-phase extraction membrane material to detect benzoylurea pesticides, and establishes a membrane solid-phase extraction-high performance liquid chromatography-tandem mass spectrometry detection method. This method has the advantages of less adsorbent consumption, short adsorption time, low desorption solvent consumption, simple operation process, wide linear range, high sensitivity, good repeatability, high recovery rate, and low detection limit, and can realize the ultra-trace detection of benzoylurea pesticides in matrices such as fruit juice and tea leaves.

Description

Technical Field

[0001] The present invention belongs to the technical field of pesticide detection and analysis, and specifically relates to a preparation method of a conjugated microporous polymer solid-phase extraction membrane material and its application in the detection of benzoylurea insecticides. Background Art

[0002] Benzoylurea insecticides are widely used in the prevention of crop pests, especially in crops such as tea trees, fruits, grains, and vegetables, due to their broad-spectrum insecticidal effects, high efficiency, and high environmental compatibility. However, benzoylurea insecticides pose potential hazards to the ecological environment and human health. The US EPA defines benzoylurea insecticides as substances of Class III and IV hazards. Japan and China have also stipulated the limit standards for benzoylurea insecticides. Therefore, it is urgent to establish a detection method for benzoylurea insecticides to achieve rapid, accurate, and efficient detection.

[0003] For the detection of benzoylurea insecticides in food and environmental samples, the sample types are diverse and complex, which is prone to matrix effects, thereby reducing the sensitivity, accuracy, and precision of the method; at the same time, the residual levels of benzoylurea insecticides are trace or ultra-trace, which not only requires highly sensitive detection means, but also requires sample pretreatment means for selective enrichment to achieve the dual effects of enrichment and purification. Currently, rapid extraction techniques mainly include dispersive solid-phase extraction, magnetic solid-phase extraction, membrane solid-phase extraction, etc. Among them, the membrane solid-phase extraction technique can immobilize the adsorbent, greatly reducing the loss of the adsorbent during the extraction process, and does not require processes such as centrifugation and magnetic adsorption, with the characteristic of simpler operation process. Therefore, the development of new membrane solid-phase extraction materials is of great significance for achieving efficient adsorption of benzoylurea insecticides and thus for the ultra-trace detection of benzoylurea insecticides in matrices such as fruit juices and tea leaves. Summary of the Invention

[0004] To solve the above problems, the purpose of the present invention is to provide a preparation method of a conjugated microporous polymer solid-phase extraction membrane material and its application in the detection of benzoylurea insecticides.

[0005] To achieve the above object, the present invention is realized through the following technical solutions:

[0006] A preparation method of a conjugated microporous polymer solid-phase extraction membrane material is prepared by the Sonogashira-Hagihara coupling reaction through interfacial polymerization of 3,5-dihydroxy-2,4,6-triiodobenzoic acid and 2,4,6-tris(4-ethynylphenyl)-1,3,5-triazine;

[0007] The structural formula of the conjugated microporous polymer solid-phase extraction membrane material is:

[0008] ;

[0009] Specifically, it includes the following steps:

[0010] 1) Preparation of the aqueous phase: Add 3,5-dihydroxy-2,4,6-triiodobenzoic acid to water, then add ethanol thereto. After ultrasonic dispersion, add alkali, tetrahydrofuran and cuprous iodide to obtain the aqueous phase;

[0011] 2) Preparation of the organic phase: Add 2,4,6-tris(4-ethynylphenyl)-1,3,5-triazine to a non-polar organic solvent, then add bis(triphenylphosphine)palladium dichloride thereto and stir to disperse evenly to obtain the organic phase;

[0012] 3) Add the aqueous phase prepared in step 1) to a reactor, then add the organic phase prepared in step 2) thereto. Under vacuum, slowly stir and react at 25 °C for 12 h, then take out the film formed at the interface and wash it 3 - 5 times with water, methanol and acetonitrile respectively, and dry it to obtain the conjugated microporous polymer solid-phase extraction membrane material.

[0013] The alkali described in step 1) is triethylamine or diisopropylethylamine.

[0014] The mass ratio of 3,5-dihydroxy-2,4,6-triiodobenzoic acid, water, ethanol, alkali, tetrahydrofuran and cuprous iodide described in step 1) is 1:70 - 100:8 - 10:15 - 20:20 - 25:0.2 - 0.3.

[0015] The non-polar organic solvent described in step 2) is toluene, n-hexane or cyclohexane.

[0016] The mass ratio of 2,4,6-tris(4-ethynylphenyl)-1,3,5-triazine, non-polar organic solvent and bis(triphenylphosphine)palladium dichloride described in step 2) is 1:80 - 100:0.4 - 0.6.

[0017] The mass ratio of 2,4,6-tris(4-ethynylphenyl)-1,3,5-triazine described in step 2) to 3,5-dihydroxy-2,4,6-triiodobenzoic acid described in step 1) is 1:0.8 - 1.

[0018] The present invention also includes the application of the conjugated microporous polymer solid-phase extraction membrane material in the detection of benzoylurea pesticides.

[0019] The method for detecting the benzoylurea pesticides is as follows: Use the conjugated microporous polymer solid-phase extraction membrane material as a membrane extraction adsorbent to perform membrane solid-phase extraction on the sample to be tested to obtain the test solution, and then use liquid chromatography-tandem mass spectrometry for detection and analysis.

[0020] The membrane solid-phase extraction process is as follows: The conjugated microporous polymer solid-phase extraction membrane material is adhered to a stainless steel wire, then immersed in a glass bottle containing a sample solution. After mixing for 1 min, it is placed in a rotary mixer with a rotation speed of 200 rpm and shaken for extraction for 2 - 30 min. After the extraction is completed, the conjugated microporous polymer solid-phase extraction membrane material is taken out, and elution is carried out by shaking in an air bath oscillator with an elution solvent for 5 - 20 min. The collected eluate is dried with nitrogen, then re-dissolved by adding elution solvent 2, shaken and vortexed for 1 min, filtered through a 0.45 μm organic filter membrane, and the test solution obtained is used for detection.

[0021] The elution solvent and elution solvent 2 are the same, and are both methanol, acetonitrile, acetone or n-hexane.

[0022] The pH of the sample solution is 2.0 - 10.0.

[0023] The mass-volume ratio of the conjugated microporous polymer solid-phase extraction membrane material, the sample solution, the elution solvent and elution solvent 2 is 3 - 12 mg: 50 mL: 1 - 5 mL: 0.5 mL.

[0024] Preferably, the pH of the sample solution is 6.0; the elution solvent is methanol; the extraction time is 5 min; the elution time is 5 min; the mass-volume ratio of the conjugated microporous polymer solid-phase extraction membrane material, the sample solution, the elution solvent and elution solvent 2 is 9 mg: 50 mL: 3 mL: 0.5 mL.

[0025] The liquid chromatography conditions are as follows: C18 chromatographic column: 100 mm × 2.1 mm × 2.6 μm; mobile phase: phase A is acetonitrile, phase B is 5 mM formic acid in water, and the gradient elution conditions are: 0 - 5 min, 45% - 20% of phase A; 5.1 - 7.0 min, 45% - 45% of phase A; 7.1 - 9.0 min, 75% of phase A; flow rate: 0.3 mL / min; column temperature: 25 °C; injection volume: 10 μL.

[0026] Since benzoylurea pesticides all contain fluorine atoms, therefore, the abundant hydroxyl groups provide abundant adsorption sites for fluoride ions, which is beneficial to the adsorption of the target by the conjugated microporous polymer solid-phase extraction membrane material. To verify this adsorption mechanism, the adsorption mechanism between benzoylurea pesticides and the conjugated microporous polymer solid-phase extraction membrane material (OH-CMPs) was verified at the molecular level by density functional theory (DFT), based on the visualization results of Visual Molecular Dynamics (VMD) (such as Figure 1As shown in the figure, taking Triflumuron as the model molecule, two different adsorption model configurations of benzoylurea insecticides on the surface of the functionalized conjugated microporous polymer solid-phase extraction membrane material were determined: (i) Triflumuron tends to be arranged parallel to the benzene ring on the nanostructured surface of the conjugated microporous polymer solid-phase extraction membrane material, forming an offset face-to-face (OFF) π-π stacking configuration; (ii) Due to the strong electronegativity of the F group in Triflumuron ( Figure 1 Figure (A)), it interacts with the highly polar -OH group ( Figure 1 Figure (B)) in the unreacted functionalized -OH group on the conjugated microporous polymer solid-phase extraction membrane material to form an -F···O-H hydrogen bond. Therefore, the enrichment of benzoylurea insecticides can be achieved quickly.

[0027] The present invention has the following advantages compared with the prior art:

[0028] The conjugated microporous polymer solid-phase extraction membrane material prepared by the present invention has a large specific surface area, abundant adsorption sites, strong hydrophobicity, and strong halogen bonds and hydrogen bonds with strong interaction forces, which can quickly achieve the enrichment of benzoylurea insecticides; using the membrane solid-phase extraction technology can immobilize the adsorbent, greatly reducing the loss of the adsorbent during the extraction process, reducing the adsorption time, and the post-treatment process is simple, and trace detection of benzoylurea insecticides can be achieved.

[0029] The present invention adopts the method of membrane solid-phase extraction. The membrane material can be separated from the sample to be tested by simply taking out the membrane material, without the need for operations such as centrifugation and magnetic adsorption. The process is convenient, further simplifies the pre-treatment steps, and reduces the losses caused by centrifugation, magnetic adsorption operations, etc. to the recovery rate.

[0030] The present invention uses the conjugated microporous polymer solid-phase extraction membrane material to detect benzoylurea insecticides, and establishes a membrane solid-phase extraction-liquid chromatography-tandem mass spectrometry detection method. This method has the advantages of less adsorbent consumption, short adsorption time, low desorption solvent consumption, simple operation process, wide linear range, high sensitivity, good repeatability, high recovery rate, and low detection limit, and can achieve ultra-trace detection of benzoylurea insecticides in matrices such as fruit juice and tea. Description of the Drawings

[0031] Figure 1 It is a diagram of the adsorption mechanism between benzoylurea insecticides and the conjugated microporous polymer solid-phase extraction membrane material; among them, (A) is a diagram of the Triflumuron model molecule; (B) is a diagram of the conjugated microporous polymer solid-phase extraction membrane material model molecule; (C) is a diagram of the interaction mechanism between Triflumuron and the conjugated microporous polymer solid-phase extraction membrane material; (D) is an isochromatic band of the control standard and the force it represents;

[0032] Figure 2 Infrared spectrum of the conjugated microporous polymer solid-phase extraction membrane material prepared in Example 3 of the present invention;

[0033] Figure 3 Scanning electron microscope image of the conjugated microporous polymer solid-phase extraction membrane material prepared in Example 3 of the present invention;

[0034] Figure 4 Contact angle test diagram of the conjugated microporous polymer solid-phase extraction membrane material prepared in Example 3 of the present invention;

[0035] Figure 5 N of the conjugated microporous polymer solid-phase extraction membrane material prepared in Example 3 of the present invention 2 Adsorption-desorption experiment diagram;

[0036] Figure 6 Membrane solid-phase extraction flow chart of the conjugated microporous polymer solid-phase extraction membrane material of the present invention;

[0037] Figure 7 Diagram for investigating the influencing factors of membrane solid-phase extraction of the conjugated microporous polymer solid-phase extraction membrane material of the present invention, where (A) is the pH influence diagram; (B) is the influence diagram of the amount of conjugated microporous polymer solid-phase extraction membrane material; (C) is the extraction time influence diagram; (D) is the influence diagram of the type of desorption solvent; (E) is the desorption time influence diagram; (F) is the influence diagram of the amount of desorption solvent. Detailed implementation manners

[0038] For a better understanding of the technical solution of the present invention, the above content of the present invention will be further described in detail through specific implementation manners in the form of examples below. However, it should not be understood that the scope of the above subject matter of the present invention is limited to the following examples. All technologies implemented based on the above content of the present invention belong to the scope of the present invention.

[0039] Example 1 Preparation of conjugated microporous polymer solid-phase extraction membrane material

[0040] 1) Preparation of the aqueous phase: Add 0.25 g of 3,5-dihydroxy-2,4,6-triiodobenzoic acid to 17.5 g of water, then add 2 g of ethanol thereto. After ultrasonic dispersion, add 3.75 g of triethylamine, 5 g of tetrahydrofuran and 0.05 g of cuprous iodide to obtain the aqueous phase;

[0041] 2) Preparation of the organic phase: Add 0.2 g of 2,4,6-tris(4-ethynylphenyl)-1,3,5-triazine to 16 g of n-hexane, then add 0.08 g of bis(triphenylphosphine)palladium dichloride thereto and stir to disperse evenly to obtain the organic phase;

[0042] 3) Add the aqueous phase prepared in step 1) into a reactor, and then add the organic phase prepared in step 2) thereto. Under vacuum, slowly stir and react at 25 °C for 12 h, then take out the film formed at the interface, wash it three times with water, methanol, and acetonitrile respectively, and dry it to obtain the conjugated microporous polymer solid-phase extraction membrane material.

[0043] Example 2 Preparation of Conjugated Microporous Polymer Solid-Phase Extraction Membrane Material

[0044] 1) Preparation of aqueous phase: Add 0.25 g of 3,5-dihydroxy-2,4,6-triiodobenzoic acid to 25 g of water, then add 2.5 g of ethanol thereto. After ultrasonic dispersion, add 5 g of diisopropylethylamine, 6.25 g of tetrahydrofuran, and 0.075 g of copper iodide to obtain the aqueous phase;

[0045] 2) Preparation of organic phase: Add 0.25 g of 2,4,6-tris(4-ethynylphenyl)-1,3,5-triazine to 25 g of cyclohexane, then add 0.15 g of bis(triphenylphosphine)palladium dichloride thereto and stir to disperse evenly to obtain the organic phase;

[0046] 3) Add the aqueous phase prepared in step 1) into a reactor, and then add the organic phase prepared in step 2) thereto. Under vacuum, slowly stir and react at 25 °C for 12 h, then take out the film formed at the interface, wash it four times with water, methanol, and acetonitrile respectively, and dry it to obtain the conjugated microporous polymer solid-phase extraction membrane material.

[0047] Example 3 Preparation of Conjugated Microporous Polymer Solid-Phase Extraction Membrane Material

[0048] 1) Preparation of aqueous phase: Add 0.25 g of 3,5-dihydroxy-2,4,6-triiodobenzoic acid to 20 g of water, then add 2.3 g of ethanol thereto. After ultrasonic dispersion, add 4 g of triethylamine, 5.5 g of tetrahydrofuran, and 0.06 g of copper iodide to obtain the aqueous phase;

[0049] 2) Preparation of organic phase: Add 0.22 g of 2,4,6-tris(4-ethynylphenyl)-1,3,5-triazine to 19.8 g of toluene, then add 0.11 g of bis(triphenylphosphine)palladium dichloride thereto and stir to disperse evenly to obtain the organic phase;

[0050] 3) Add the aqueous phase prepared in step 1) into a reactor, and then add the organic phase prepared in step 2) thereto. Under vacuum, slowly stir and react at 25 °C for 12 h, then take out the film formed at the interface, wash it five times with water, methanol, and acetonitrile respectively, and dry it to obtain the conjugated microporous polymer solid-phase extraction membrane material.

[0051] Perform FTIR characterization on the conjugated microporous polymer solid-phase extraction membrane material prepared in Example 3, and its detection spectrum is asFigure 2 As shown, by Figure 2 It can be seen that the characteristic signal peak of -C≡CH (3290 cm -1 ) in the raw material 2,4,6-tris(4-ethynylphenyl)-1,3,5-triazine (TEPT) and the stretching vibration peak of -C-I (564 cm -1 ) in 3,5-dihydroxy-2,4,6-triiodobenzoic acid (HTIB) basically disappear, indicating that the Sonogashira reaction has occurred between the two raw materials. At the same time, in the infrared spectrum of the conjugated microporous polymer solid-phase extraction membrane material, a new characteristic peak of -C≡C- (2205 cm -1 ) is observed, confirming that a polymer is formed between the two monomers through the Sonogashira reaction.

[0052] The conjugated microporous polymer solid-phase extraction membrane material prepared in Example 3 was subjected to scanning electron microscopy detection and contact angle measurement. The detection results are as shown in Figure 3 and Figure 4 As shown, by Figure 3 It can be seen that the surface of the conjugated microporous polymer solid-phase extraction membrane material has a rod-like morphological structure, indicating that the prepared conjugated microporous polymer solid-phase extraction membrane material has a large specific surface area and good stability, and the internal channels of the rod-like structure are conducive to molecular diffusion, thereby improving the adsorption rate. By Figure 4 It can be seen that the contact angle of the conjugated microporous polymer solid-phase extraction membrane material is 148°, indicating that the material has strong hydrophobicity, and thus can effectively adsorb the target substance.

[0053] The conjugated microporous polymer solid-phase extraction membrane material prepared in Example 3 was subjected to N 2 adsorption-desorption experiment. The detection results are as shown in Figure 5 As shown, by Figure 5 It can be seen that the specific surface area of the conjugated microporous polymer solid-phase extraction membrane material is 427.0 m 2 / g, indicating that the prepared membrane material has a good specific surface area.

[0054] Example 4 (1) Liquid chromatography-tandem mass spectrometry conditions

[0055] Instrument model: Liquid chromatography-triple quadrupole mass spectrometer (6470 LC / TQ, Agilent Technologies, Inc., USA).

[0056] Liquid chromatography column conditions: Thermo C18 chromatographic column (100 mm × 2.1 mm × 2.6 μm); mobile phase: phase A is acetonitrile, phase B is 5 mM formic acid in water, and the gradient elution conditions are: 0 - 5 min, 45% - 20% of phase A; 5.1 - 7.0 min, 45% - 45% of phase A; 7.1 - 9.0 min, 75% of phase A; flow rate: 0.3 mL / min; column temperature: 25 °C; injection volume: 10 μL.

[0057] Mass spectrometry parameters: In this application, an electrospray ionization source (ESI) is used, and the selected multiple reaction monitoring (MRM) mode is adopted for quantification; drying gas temperature: 300 °C, drying gas flow rate: 5 L / min, nebulizer voltage: 35 psi, capillary voltage: 4000 V, sheath gas flow rate: 11 L / min, sheath gas temperature: 300 °C. The optimized MRM parameters including qualitative ions, quantitative ions, their declustering voltages and collision energies are shown in Table 1, where * represents the quantitative ion.

[0058] Table 1 Optimized parameter table

[0059]

[0060] (2) Membrane solid-phase extraction (the flow chart is as Figure 6 shown)

[0061] The conjugated microporous polymer solid-phase extraction membrane material prepared in Example 3 of the present invention was adhered to a stainless steel wire and then immersed in a glass bottle containing 50 mL of an aqueous solution. The spiked concentrations of 6 benzoylurea pesticides (triflumuron, chlorfluazuron, flucycloxuron, flufenoxuron, lufenuron, chlorfluazuron) in the aqueous solution were 500 ng / L. After mixing for 1 min, it was placed in a rotary mixer with a rotation speed of 200 rpm and shaken for extraction for 2 - 30 min. After the extraction was completed, the conjugated microporous polymer solid-phase extraction membrane material was taken out, and it was shaken and desorbed in a gas bath oscillator with a desorption solvent for 5 - 20 min. The collected eluate was dried with nitrogen, then redissolved with desorption solvent 2, shaken and vortexed for 1 min, filtered through a 0.45 μm organic filter membrane to obtain the test solution for detection, and each group of experiments was repeated three times in parallel.

[0062] In this experiment, the influence of the pH of the sample solution (2.0 - 10.0) on the extraction of benzoylurea pesticides was investigated, and the detection spectrum is as Figure 7 shown in (A). When the pH was 6.0, the recovery rates of the 6 benzoylurea pesticides were the highest, about 95% or so. At other pH values, the recovery rates of the 6 benzoylurea pesticides decreased slightly, about 85% or so. Therefore, the pH of the sample solution was determined to be 6.

[0063] This experiment investigated the effect of the amount of conjugated microporous polymer solid-phase extraction membrane material (3 mg, 6 mg, 9 mg, 12 mg) on the extraction of benzoylurea pesticides. The detection spectra are shown as Figure 7 in (B). It can be seen from the experimental results that with the increase in the amount of conjugated microporous polymer solid-phase extraction membrane material, the extraction efficiency gradually increases. When the amount of conjugated microporous polymer solid-phase extraction membrane material is 9 mg, the recovery rate of the target substances reaches more than 90%, indicating that 9 mg of conjugated microporous polymer solid-phase extraction membrane material is sufficient to achieve the enrichment of 6 benzoylurea pesticides. Therefore, the amount of conjugated microporous polymer solid-phase extraction membrane material was determined to be 9 mg.

[0064] This experiment investigated the effect of extraction time (2 - 30 min) on the extraction of benzoylurea pesticides. The detection spectra are shown as Figure 7 in (C). It can be seen from the experimental results that at 2 min, the extraction efficiency of 6 benzoylurea pesticides all reached more than 60%, but there was a certain degree of dispersion. With the increase in extraction time, the extraction efficiency gradually increased. When the extraction time was 5 min, the recovery rate of 6 benzoylurea pesticides was as high as 90%. Therefore, the extraction time was determined to be 5 min.

[0065] This experiment investigated the effect of elution solvents (methanol, acetonitrile, acetone, and n-hexane) on the extraction of benzoylurea pesticides. The detection spectra are shown as Figure 7 in (D). It can be seen from the experimental results that methanol, acetone, and acetonitrile all had high elution capabilities for 6 benzoylurea pesticides, while the elution ability of n-hexane was the lowest. However, considering that the influence of pigments and the like should be minimized during the detection of actual samples of tea beverages, and acetone solvent often dissolves more pigments. Secondly, from the perspective of economy, the elution cost of acetonitrile is higher. Therefore, the elution solvent was determined to be methanol.

[0066] This experiment investigated the effect of elution time (5 - 20 min) and elution solvent volume (1 - 5 mL) on the extraction of benzoylurea pesticides. The detection spectra are shown as Figure 7 in (E) and Figure 7 in (F). It can be seen from the experimental results that when the elution time was 5 min, the recovery rate of 6 benzoylurea pesticides was as high as 90%. Prolonging the elution time did not change the elution efficiency. Therefore, the elution time was determined to be 5 min. When the volume of elution solvent methanol was in the range of 1 - 3 mL, the elution efficiency increased with the increase in elution volume, and the elution rate was 80%. When the volume of methanol continued to increase, the elution rate hardly changed. Therefore, from the perspectives of environmental protection and saving nitrogen blowing time, the elution solvent volume was determined to be 3 mL.

[0067] The finally determined optimal parameters for membrane solid-phase extraction are as follows: the pH of the sample solution is 6.0; the elution solvent is methanol; the extraction time is 5 min; the elution time is 5 min; the mass-volume ratio of the conjugated microporous polymer solid-phase extraction membrane material, the sample solution, the elution solvent, and the second elution solvent is 9 mg:50 mL:3 mL:0.5 mL.

[0068] Example 5 (1) Preparation of the mixed standard solution of benzoylurea insecticides: Accurately weigh 100.0 mg of high-purity reagents of chlorfluazuron, hexaflumuron, flufenoxuron, flucycloxuron, lufenuron, and chlorantraniliprole respectively, dissolve them with methanol and transfer them to a 10 mL volumetric flask, add methanol to the scale line, shake well, and obtain single-standard stock solutions with a mass concentration of 10 mg / mL. Accurately measure 1.00 mL of the single-standard stock solutions of chlorfluazuron, hexaflumuron, flufenoxuron, flucycloxuron, lufenuron, and chlorantraniliprole respectively, place them in a 100 mL brown volumetric flask, add methanol to the scale line, shake well, and obtain a mixed standard solution of benzoylurea insecticides with a mass concentration of 100 μg / mL. This mixed standard solution is stored refrigerated at -4°C and has a shelf life of one year.

[0069] (2) Preparation of the standard working solutions of benzoylurea insecticides: Dilute the 100 μg / mL mixed standard solution of benzoylurea insecticides into standard working solutions of benzoylurea insecticides with concentrations of 0.5, 1, 2.5, 5, 10, 25, 40, 50, and 100 μg / L respectively;

[0070] (3) Detect the standard working solutions of benzoylurea insecticides prepared in step (2) by liquid chromatography-tandem mass spectrometry, and establish a standard curve according to the corresponding relationship between the chromatographic peak area and the mass concentration of the standard working solutions of benzoylurea insecticides; the detection results are shown in Table 2.

[0071] Table 2 Determination results of the standard curve

[0072]

[0073] As can be seen from the results in Table 2, the 6 benzoylurea insecticides show a good linear relationship in the concentration range of 0.5 - 100 ng / L, the linear correlation coefficient is higher than 0.999, the detection limit LODs (S / N = 3) of the method is 0.08 - 0.60 ng / L, and the quantification limit LOQs (S / N = 10) of the method is 0.29 - 2.00 ng / L. The experimental results show that the method for determining benzoylurea insecticides established by membrane solid-phase extraction-liquid chromatography-tandem mass spectrometry has high sensitivity, good repeatability, low detection limit and quantification limit, and can achieve trace detection of benzoylurea insecticides.

[0074] Example 6 Determination of samples

[0075] (1) Preparation of sample solution

[0076] Groundwater and surface water were selected as actual water samples for analysis. After the environmental water samples were filtered through a water-based filter membrane with a pore size of 0.45 µm, the pH was adjusted to 6, stored in clean brown glass bottles, and kept at 4 °C for later use.

[0077] Green tea and black tea samples were ground into fine powder by a grinder. Accurately weigh 0.50 g of tea powder and place it in a 50 mL centrifuge tube, add 2.5 mL of acidified acetonitrile (1% formic acid), vortex for 5 min. After extraction, centrifuge at 8000 rpm for 5 min to separate the supernatant. Repeat the same extraction operation once, combine the supernatants from the two extractions, and finally transfer the supernatant to a clean 50 mL flat-bottom glass tube with a lid. Dilute the supernatant to 50 mL with ultrapure water, and adjust the pH of the sample solution to 6.0 for later use.

[0078] Grape juice and apple juice were filtered through a water-based filter membrane with a pore size of 0.45 µm, the pH was adjusted to 6, stored in clean brown glass bottles, and kept at 4 °C for later use.

[0079] (2) Membrane solid-phase extraction

[0080] 9 mg of the conjugated microporous polymer solid-phase extraction membrane material prepared in Example 3 of the present invention was adhered to a stainless steel wire, and then immersed into glass bottles containing 50 mL of the sample solution prepared in step (1) respectively. After mixing for 1 min, it was placed in a rotary mixer with a rotation speed of 200 rpm and shaken for extraction for 5 min. After extraction, the conjugated microporous polymer solid-phase extraction membrane material was taken out, and 3 mL of methanol was used to shake and desorb in a gas bath oscillator for 5 min. The collected eluate was dried with nitrogen, then 0.5 mL of methanol was added for reconstitution, vortexed for 1 min, and filtered through a 0.45 μm organic filter membrane to obtain the test solution.

[0081] (3) Setting the liquid chromatography-tandem mass spectrometry conditions

[0082] Instrument model: Liquid chromatography-triple quadrupole mass spectrometer (6470 LC / TQ, Agilent Technologies, Inc., USA).

[0083] Liquid chromatography column conditions: Thermo Fisher C18 chromatographic column (100 mm × 2.1 mm × 2.6 μm); Mobile phase: Phase A is acetonitrile, Phase B is 5 mM formic acid water, and the gradient elution conditions are: 0 - 5 min, 45% - 20% of Phase A; 5.1 - 7.0 min, 45% - 45% of Phase A; 7.1 - 9.0 min, 75% of Phase A; Flow rate: 0.3 mL / min; Column temperature: 25 °C; Injection volume: 10 μL.

[0084] Mass spectrometry parameters: In this application, an electrospray ionization source (ESI) is used, and the selected multiple reaction monitoring (MRM) mode is adopted for quantification; drying gas temperature: 300 °C, drying gas flow rate: 5 L / min, nebulizer voltage: 35 psi, capillary voltage: 4000 V, sheath gas flow rate: 11 L / min, sheath gas temperature: 300 °C.

[0085] (4) The test solutions prepared in step (2) were respectively subjected to liquid chromatography-tandem mass spectrometry determination. Then, low and high concentration spike recovery experiments were respectively carried out on 6 samples with 20 ng / L and 500 ng / L spike addition, and each group of samples was measured in parallel 3 times. The test results are shown in Table 3.

[0086] Table 3 Sample determination and spike recovery rate results

[0087]

[0088] As can be seen from the results in Table 3, the concentration of flucumuron in grape juice is 0.66 ng / L, the concentration of flucumuron in apple juice is 0.68 ng / L, and the residues of benzoylurea pesticides were not detected in other samples. Low (20 ng / L) and high concentration (500 ng / L) spike recovery experiments were respectively carried out on 6 samples, and the results showed that the recovery rates of 6 benzoylurea pesticides were between 72% and 120%, and the measured recovery rates all met the requirements of the measurement method in the SANTE / 11945 / 2015 guideline.

[0089] Although the specific implementation manners of the present invention are described above, it is not a limitation on the protection scope of the present invention. Based on the technical solutions of the present invention, various modifications or deformations that can be made by those skilled in the art without creative efforts are still within the protection scope of the present invention.

Claims

1. An application of a conjugated microporous polymer solid phase extraction membrane material, characterized in that: Application in the detection of benzoylurea pesticides; The conjugated microporous polymer solid phase extraction membrane material is prepared by interfacial polymerization of 3,5-dihydroxy-2,4,6-triiodobenzoic acid and 2,4,6-tris(4-ethynylphenyl)-1,3,5-triazine to produce a Sonogashira-Hagihara coupling reaction; The structural formula of the conjugated microporous polymer solid phase extraction membrane material is: ； The specific steps include: 1) Preparation of aqueous phase: 3,5-dihydroxy-2,4,6-triiodobenzoic acid is added to water, and then ethanol is added thereto. After ultrasonic dispersion, alkali, tetrahydrofuran and cuprous iodide are added to obtain an aqueous phase; 2) Preparation of an organic phase: adding 2,4,6-tris(4-ethynylphenyl)-1,3,5-triazine to a non-polar organic solvent, and then adding bistriphenylphosphine palladium dichloride thereto, stirring and dispersing the mixture evenly to obtain an organic phase; 3) The aqueous phase prepared in step 1) is added to the reactor, and then the organic phase prepared in step 2) is added thereto. After slowly stirring and reacting for 12 hours at 25° C. under vacuum, the thin film formed at the interface is taken out, washed with water, methanol and acetonitrile for 3 to 5 times respectively, and dried to obtain a conjugated microporous polymer solid phase extraction membrane material.

2. The use of the conjugated microporous polymer solid phase extraction membrane material according to claim 1 in the detection of benzoylurea pesticides, characterized in that: The base in step 1) is triethylamine or diisopropylethylamine; the mass ratio of 3,5-dihydroxy-2,4,6-triiodobenzoic acid, water, ethanol, base, tetrahydrofuran and cuprous iodide in step 1) is 1:70-100:8-10:15-20:20-25:0.2-0.

3.

3. The use of the conjugated microporous polymer solid phase extraction membrane material according to claim 1 in the detection of benzoylurea pesticides, characterized in that: The non-polar organic solvent in step 2) is toluene, n-hexane or cyclohexane; the mass ratio of 2,4,6-tris(4-ethynylphenyl)-1,3,5-triazine, the non-polar organic solvent and bistriphenylphosphine palladium dichloride in step 2) is 1:80~100:0.4~0.6; the mass ratio of 2,4,6-tris(4-ethynylphenyl)-1,3,5-triazine in step 2) to 3,5-dihydroxy-2,4,6-triiodobenzoic acid in step 1) is 1:0.8~1.

4. The use of the conjugated microporous polymer solid phase extraction membrane material according to claim 1 in the detection of benzoylurea pesticides, characterized in that: The method for detecting benzoylurea pesticides comprises: using the conjugated microporous polymer solid phase extraction membrane material as a membrane extraction adsorbent to perform membrane solid phase extraction on a sample to be tested to obtain a test liquid, and then using liquid chromatography-tandem mass spectrometry for detection and analysis.

5. The use of the conjugated microporous polymer solid phase extraction membrane material as claimed in claim 4 in the detection of benzoylurea pesticides, characterized in that: The membrane solid phase extraction process is as follows: a conjugated microporous polymer solid phase extraction membrane material is applied to a stainless steel wire, and then immersed in a glass bottle containing a sample solution, mixed for 1 minute, and then placed in a rotary mixer at a speed of 200 rpm for oscillation extraction for 2 to 30 minutes. After the extraction is completed, the conjugated microporous polymer solid phase extraction membrane material is taken out, and an analytical solvent is used to oscillate and analyze in an air bath oscillator for 5 to 20 minutes. The collected eluate is blown dry with nitrogen, and then the analytical solvent 2 is added for redissolution, vortexed for 1 minute, and filtered with a 0.45 μm organic filter membrane to obtain a test solution for detection.

6. The use of the conjugated microporous polymer solid phase extraction membrane material according to claim 5 in the detection of benzoylurea pesticides, characterized in that: The analytical solvent is the same as analytical solvent 2, which is methanol, acetonitrile, acetone or n-hexane; the pH of the sample solution is 2.0-10.0; the mass volume ratio of the conjugated microporous polymer solid phase extraction membrane material, sample solution, analytical solvent and analytical solvent 2 is 3-12 mg: 50 mL: 1-5 mL: 0.5 mL.

7. The use of the conjugated microporous polymer solid phase extraction membrane material as claimed in claim 5 in the detection of benzoylurea pesticides, characterized in that: The pH of the sample solution is 6.0; the analytical solvent is methanol; the extraction time is 5 min; the analytical time is 5 min; The mass volume ratio of the conjugated microporous polymer solid phase extraction membrane material, the sample solution, the analytical solvent and the analytical solvent 2 is 9 mg: 50 mL: 3 mL: 0.5 mL.

8. The use of the conjugated microporous polymer solid phase extraction membrane material according to claim 4 in the detection of benzoylurea pesticides, characterized in that: The liquid chromatography conditions are as follows: C18 chromatographic column: 100 mm × 2.1 mm × 2.6 μm; mobile phase: phase A is acetonitrile, phase B is 5 mM formic acid water, gradient elution conditions are: 0-5 min, phase A 45%-20%; 5.1-7.0 min, phase A 45%-45%; 7.1-9.0 min, phase A 75%; flow rate: 0.3 mL / min; Column temperature: 25°C; injection volume: 10 μL.

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