Characterization method of purification performance of purification material for pesticide residue detection and application

Abstract

The invention belongs to the field of purification performance analysis of purification materials, and particularly relates to a characterization method of purification performance of a purification material for pesticide residue detection and application. According to the characterization method for the purification performance of the purification material for pesticide residue detection, the purification material is evaluated on the overall level, the molecular level and the matrix effect level respectively, and the overall purification capacity of the purification material on a matrix, the internal action relation between the purification material and matrix molecules and the matrix effect expression for specific pesticide residue molecules are reflected respectively; related purification results can form multi-dimensional characteristic attributes related to the purification performance of the purification material, and comprehensive evaluation of the purification performance of the purification material is achieved. Related evaluation results can provide guidance for model selection of the QuEChERS purification material and development of the novel QuEChERS purification material.

Description

Technical Field

[0001] The invention belongs to the field of purification performance analysis of purification materials, and specifically relates to a method for characterizing the purification performance of a purification material for pesticide residue detection and an application thereof. Background Art

[0002] The QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method is a new rapid sample pretreatment technology developed by Professor Anastassiades of the United States Department of Agriculture and his collaborators in 2003. It has the advantages of being fast, simple, cheap, safe, reliable and having a high recovery rate. The working principle of QuEChERS pretreatment technology is similar to solid phase extraction. It uses the interaction between the purification material and the impurities in the matrix to adsorb impurities and achieve the purpose of impurity removal and purification. The technology is simple to operate and mainly includes three steps: (1) extracting residual pesticides using acetonitrile; (2) adding salting-out agents such as anhydrous magnesium sulfate to separate the layers; (3) adding purification materials such as ethylenediamine-N-propylsilane silica gel (PSA) to remove impurities. QuEChERS technology has been widely used in the field of pesticide residue detection due to its advantages such as being fast, simple, cheap, effective, stable and safe.

[0003] In view of the complex sample matrix and the high number of interferences, the impurity removal and purification step is becoming increasingly important for the analysis and detection of residual pesticides. The selection of appropriate purification materials to effectively remove impurities in the matrix is ​​extremely important for reducing the detection limit and ensuring the accuracy of the test results. Different purification materials have different purification characteristics. For example, ethylenediamine-N-propyl silane silica gel (PSA) achieves effective adsorption of corresponding compounds based on its chemical structure and functional groups (such as primary amines, secondary amines, etc.); octadecylsilane bonded silica gel (C18) achieves rapid adsorption of non-polar compounds based on its lipophilicity and selectivity; graphitized carbon black (GCB) exhibits a strong affinity for planar molecules based on its hexagonal ring structure. How to characterize and evaluate the purification performance of purification materials to help select purification materials for different samples (such as tobacco, tea, spinach, grapes, citrus, onions, etc.) is of great significance for the detection of pesticide residues using QuEChERS.

[0004] At present, the evaporation residue weight method is often used to evaluate the purification ability of purification materials. It is to weigh the evaporation residue of the extract before and after purification, and evaluate the purification ability by the weight of the evaporation residue. If the evaporation residue weight of the extract after purification is smaller, it means that the purification material removes more matrix, and the overall purification effect of the purification material is better.

[0005] The evaporation residue weight method only characterizes the overall purification ability of the purification material, but it cannot reasonably explain key issues such as the actual impact on pesticide residue detection, which specific matrix molecules the purification material interacts with, and how to optimize the purification ability of the purification material. This leads to blindness in the selection of purification materials and the development of new purification materials. The implementation of efficient QuEChERS methods for different sample matrices and pesticide residues still faces great challenges. Summary of the invention

[0006] The first object of the present invention is to provide a method for characterizing the purification performance of purification materials for pesticide residue detection, thereby solving the problem that the existing methods cannot fully reflect the characteristic properties of purification materials.

[0007] The second objective of the present invention is to provide an application of the above characterization method in the screening of purification materials, so as to solve the problems of blindness and low efficiency in the selection of existing purification materials.

[0008] In order to achieve the first purpose, the technical solution adopted by the present invention is:

[0009] A method for characterizing the purification performance of purification materials for pesticide residue detection, including evaluating the purification performance of purification materials at the overall level, molecular level and matrix effect level:

[0010] The overall level evaluation includes determining the weight of the evaporation residue before and after the extraction liquid is purified, and evaluating the overall purification capacity based on the weight of the evaporation residue;

[0011] The molecular level evaluation includes determining the mass spectrometry response intensity for different matrix molecule types before and after the extraction solution is purified, and evaluating the purification ability of the purification material for the corresponding matrix molecules according to the degree of decrease in the mass spectrometry response intensity;

[0012] The evaluation at the matrix effect level is aimed at pesticide residue detection, including performing linear regression analysis on a pesticide residue standard solution to obtain the slope of a solvent standard curve; using the purification material to purify a blank sample that does not contain the pesticide residue to be detected, and then using the pesticide residue standard solution to prepare a matrix matching standard solution, performing linear regression analysis on the matrix matching standard solution to obtain the slope of the matrix matching standard curve; calculating the ratio of the slope of the matrix matching standard curve to the slope of the solvent standard curve, and using the ratio to evaluate the purification ability of the purification material for pesticide residues.

[0013] The present invention is an improved invention, which evaluates the purification material at the overall level, molecular level and matrix effect level respectively, reflecting the overall purification ability of the purification material on the matrix, the intrinsic interaction relationship with the matrix molecules and the matrix effect performance on specific pesticide residue molecules respectively. The relevant purification results can form multi-dimensional characteristic attributes related to the purification material and the purification performance, thereby realizing a comprehensive evaluation of the purification performance of the purification material.

[0014] Based on the above evaluation results, guidance can be provided for the selection of QuEChERS purification materials and the development of new QuEChERS purification materials.

[0015] Preferably, the mass spectrometry response intensity is obtained by performing liquid chromatography-high resolution mass spectrometry detection on the extract before and after purification.

[0016] Further preferably, the chromatographic conditions of the liquid chromatography-high resolution mass spectrometry are: chromatographic column: Atlantis@T3 column; mobile phase A: 5 mM ammonium acetate aqueous solution with 0.1% formic acid; mobile phase B: acetonitrile; gradient elution, elution gradient: 0-1 min, 10%-50% B; 1-5 min, 50% B; 5-16 min, 50%-60% B; 16-25 min, 60%-80% B; 25-30 min, 80%-95% B; 30-40 min, 95% B; 40-40.1 min, 95%-10% B; 40.1-50.1 min, 10% B;

[0017] The mass spectrometry conditions were as follows: ESI source; scanning mode: positive ion scanning; scanning range: 100-1000 m / z; spray voltage: 5500 V; nebulizing gas pressure: 55 psi; curtain gas pressure: 35 psi; auxiliary gas pressure: 50 psi; ion source temperature: 500°C; cluster fragmentation voltage: 40 V; collision energy diffusion: 15 eV; detection mode: information correlation acquisition mode.

[0018] Preferably, in the molecular level evaluation, the purification ability of the purification material on the corresponding matrix molecules is quantified according to the following formula:

[0019] A=(I B -I A ) / I B ×100%

[0020] In the formula, I B and I A are the mass spectrometric response intensities of matrix molecules in the extract before and after purification, respectively.

[0021] Preferably, in the molecular level evaluation, the matrix molecule types include one or more of alkaloids, polyphenols, pigments, organic acids, and sulfur-containing compounds.

[0022] Preferably, in the evaluation of the matrix effect level, the ratio equal to 1 indicates the best purification ability, and the greater the deviation from 1, the worse the purification ability.

[0023] Preferably, in the evaluation at the matrix effect level, the pesticide residues to be detected include one or more of thiodicarb, pendimethalin, ethophos sulfoxide, isopimide, fenthion sulfoxide, phoxim, quinalphos, triadimefon, clomazone, pyraclostrobin, profenofos, fluazifop-butyl, indoxacarb, penconazole, hexythiazox, difenoconazole, butalin, ethophos, fenamiphos, fenamiphos sulfone, methyl pirimiphos, phosalone, pyrifos, triazophos, azoxystrobin, chlorfenapyr, ethophos, chlorfenapyr, ethophos, methidathion, manganese salt of prochloraz, and tebuconazole.

[0024] Preferably, in the evaluation at the matrix effect level, the purification treatment includes extracting the blank sample with a solvent to obtain an extract, mixing the purification material with the extract, and then performing solid-liquid separation to obtain a purified extract.

[0025] In order to achieve the above second purpose, the technical solution adopted by the present invention is:

[0026] The above-mentioned method for characterizing the purification performance of purification materials for pesticide residue detection is applied in the screening of purification materials.

[0027] Using the results of the above characterization methods, the interaction between purification materials and matrix molecules and the matrix effect of pesticide residues in QuEChERS treatment can be quantitatively evaluated, and the actual performance of purification materials in QuEChERS treatment can be combined with the intrinsic matrix molecular mechanism, which is conducive to the rapid screening of purification materials with good purification effects and strong pertinence, and improves the selection efficiency of purification materials. In addition, according to the results of the above characterization methods, the structure, surface groups and other characteristics of the purification materials can also be linked to the purification effect, thereby providing guidance for the development of new purification materials.

[0028] Preferably, different purification materials are ranked in terms of purification capabilities at the overall level, molecular level and matrix effect level, and the purification materials are selected or combined according to the matrix type and the pesticide residue to be detected. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The results of evaluating the amount of extraction matrix of different purification materials in the embodiments of the present invention are as follows;

[0030] Figure 2 The following are the evaluation results of the purification performance of different purification materials on matrix molecules (lutein and β-carotene) in the examples of the present invention. DETAILED DESCRIPTION

[0031] The technical concept of the present invention is to give a multi-dimensional label to the purification performance of the purification material. The overall level label reflects the overall purification ability of the matrix, the molecular level label reflects the interaction relationship with the matrix molecules, and the matrix effect level label reflects the anti-interference performance of specific pesticide residue molecules in the actual QuEChERS treatment. The multi-dimensional label more richly depicts the purification performance of the purification material, thereby providing basic information for a comprehensive understanding of the purification performance of the purification material, and providing guidance for the efficient selection of QuEChERS purification materials and the development of new QuEChERS purification materials.

[0032] The evaluation at the overall level was conducted by the traditional evaporation residue weight method. The evaluation at the molecular level was conducted by the decrease in mass spectrometry response intensity. The evaluation at the matrix effect level was conducted by quantitative evaluation using the matrix effect feedback method.

[0033] The following is an explanation of the general process of the three-level evaluation:

[0034] 1. Overall evaluation

[0035] 1.1 Pre-treat the sample to obtain the extract before purification. The pre-treatment here is a routine operation for pesticide residue detection, generally including solvent extraction, salting out and stratification (if necessary), and the obtained supernatant is the extract before purification.

[0036] 1.2 Use the purification material to purify the extract before purification to obtain the purified extract. The purification process can be carried out by mixing and oscillating to speed up the purification efficiency. After mixing and oscillating, centrifuge, filter the supernatant through a membrane, and the filtrate obtained is the purified extract.

[0037] Here, the volume of the extract before purification is 0.5 to 3 mL, and the mass of the purification material is 3 to 300 mg. When the sample to be analyzed is tobacco leaves, 10 mL of water is used to shake each 2.00 g of tobacco end sample until the sample is soaked and then allowed to stand, and then 10 mL of acetonitrile is added for oscillation extraction. Each 2.00 g of tobacco end sample can be purified using 10 to 20 mg of purification material.

[0038] 1.3 Evaporate the solvent of the purified extract to obtain the evaporation residue. The evaporation residue of the blank processed extract without purification is used as a benchmark, and the weight of the evaporation residue after purification is used to evaluate the overall purification effect of the purification material.

[0039] Specifically, the purified extract is placed in a clean chromatographic bottle weighed in advance, first blown with nitrogen, then placed in an oven for drying, taken out and placed in a desiccator for cooling. The chromatographic bottle containing the remaining extract is weighed using an analytical balance, and then the weight of the chromatographic bottle is subtracted to obtain the weight of the extraction matrix (i.e., the weight of the evaporation residue). The lower the weight of the extraction matrix relative to the blank treatment (purification without the use of purification material), the better the overall purification effect of the purification material.

[0040] 2. Evaluation at the molecular level

[0041] 2.1 Obtain the extract before purification and the extract after purification; the processing here is the same as step 1.1 and step 1.2.

[0042] 2.2 Liquid chromatography-high resolution mass spectrometry is used to detect the extract before purification and the extract after purification respectively to obtain the mass spectrometry response intensity of different matrix molecule types. Here, the high resolution mass spectrometry can be time-of-flight mass spectrometry, orbital trap mass spectrometry, magnetic mass spectrometry, Fourier transform ion cyclotron resonance mass spectrometry, and the detection adopts full scan mode and synchronously collects secondary mass spectrometry or multi-stage mass spectrometry.

[0043] 2.3 The purification ability of the purification material for different matrix molecules is evaluated by the degree of decrease in the mass spectrometry response intensity of the matrix molecules.

[0044] Specifically, the purification capacity is quantitatively evaluated using the following formula:

[0045] A=(I B -I A ) / I B ×100%

[0046] Among them, I B and I A are the mass spectrometry response intensities of the matrix molecules in the extract before and after purification, respectively; the value range of A is 0% to 100%, and the larger the value, the stronger the purification ability.

[0047] 3. Evaluation of matrix effect

[0048] 3.1 Prepare a series of pesticide residue standard solutions containing internal standards, perform linear regression analysis after detection and analysis, and obtain the slope of the solvent standard curve. The detection and analysis method can be liquid chromatography-tandem mass spectrometry or liquid chromatography-high resolution mass spectrometry; the horizontal axis of the obtained solvent standard curve is the concentration of the standard solution, and the vertical axis is the response ratio of the target pesticide residue to the internal standard.

[0049] 3.2 Pre-treat the blank sample that does not contain the pesticide residue to be detected to obtain the pre-purification treatment solution. Use the purification material to purify the pre-purification treatment solution to obtain the purified extract (i.e., the blank sample extract). The pre-treatment operation here is the same as the pre-treatment in step 1.1, and the purification operation is the same as the purification operation in step 1.2. Blank samples that do not contain the pesticide residue to be detected can generally be obtained by purchasing or applying from official agencies. For example, blank flue-cured tobacco dust samples can be purchased or applied for from the organizers of the UK Food Analysis Capability Assessment System (FAPAS).

[0050] 3.3 Take a certain volume of the purified blank sample extract, blow it dry with nitrogen, and then re-dissolve it with a certain volume of a series of pesticide residue standard solutions containing internal standards to obtain a series of matrix-matched standard solutions. The volume of the blank sample extract and the series of pesticide residue standard solutions containing internal standards are the same, both 0.3-3mL. The concentration of the series of pesticide residue standard solutions containing internal standards is consistent with the concentration of the pesticide residue standard solution in step 3.1.

[0051] 3.4 After the series of matrix-matched standard solutions are tested and analyzed, a linear regression analysis is performed to obtain the slope of the matrix-matched standard curve. The detection and analysis means and linear regression analysis method of this step are consistent with those of step 3.1.

[0052] 3.5 Calculate the ratio of the slope of the matrix-matched standard curve in step 3.4 to the slope of the solvent standard curve in step 3.1. This slope ratio can be used to characterize the matrix effect. A ratio equal to 1 indicates no matrix effect (corresponding to the best purification ability), and the more it deviates from 1, the more severe the matrix effect (corresponding to the worse purification ability).

[0053] The evaluation results at the matrix effect level can directly provide feedback on the matrix effect of specific pesticide residues detected after purification by QuEChERS purification materials. On the other hand, the differences in purification performance of QuEChERS purification materials can be evaluated by comparing the slope ratios when using different QuEChERS purification materials.

[0054] The implementation process of the present invention is described in detail below in conjunction with specific embodiments.

[0055] 1. Specific embodiments of the method for characterizing the purification performance of the purification material for pesticide residue detection of the present invention

[0056] Example 1

[0057] The method for characterizing the purification performance of the purification material for pesticide residue detection in this embodiment includes evaluating the purification performance of the purification material CZIF at the overall level, the molecular level and the matrix effect level; there is no restriction or requirement on the type of purification material, and any purification material with purification ability is applicable to this method. CZIF is a carbon-based adsorption material obtained by high-temperature pyrolysis of zeolite-like structure MOF materials, and its pores and surface properties are used to achieve purification adsorption.

[0058] 1. Overall evaluation

[0059] 1.1 Weigh about 2.00g of cigarette dust sample into a 50mL stoppered centrifuge tube, add 10mL of water and shake until the sample is fully infiltrated, then let it stand for 10min, then add 10mL of acetonitrile and 20μL of 10μg / mL triphenyl phosphate internal standard solution, and shake at 2000rpm for 2min. After placing the centrifuge tube at -20℃ for 10min, add 4g of anhydrous magnesium sulfate, 1g of sodium chloride, 1g of sodium citrate and 0.5g of disodium hydrogen citrate in sequence, immediately shake at 2000rpm for 2min, then centrifuge at 5000rpm for 3min, take 1mL of the supernatant into a 2mL centrifuge tube, add 150mg of anhydrous magnesium sulfate and 10mg of CZIF, shake for 2min and centrifuge to obtain the supernatant (purified extract).

[0060] In this step, anhydrous magnesium sulfate, sodium chloride, sodium citrate and disodium hydrogen citrate are used as salting-out agents; the centrifuge tube is placed in a -20°C freezer for 10 minutes for pre-cooling to prevent the subsequent addition of the salting-out agent from causing heat release and causing the extract temperature to be too high.

[0061] 1.2 Take 0.5 mL of the purified extract into a pre-weighed clean chromatographic bottle, blow it with nitrogen, then put it in an 80°C oven for 2 h, take it out and cool it in a desiccator, weigh the chromatographic bottle containing the extraction matrix using an analytical balance, and then subtract the weight of the chromatographic bottle to obtain the amount of extraction matrix. Repeat the process three times to obtain the following: Figure 1 The blank is the treatment group without any purification material (equivalent to the evaporation residue of the extract before purification, as a comparison benchmark). The lower the amount of extraction matrix, the better the overall purification effect of the purification material.

[0062] 2. Molecular level evaluation

[0063] 2.1 Weigh about 2.00g of tobacco dust sample into a 50mL stoppered centrifuge tube, add 10mL of water and shake until the sample is fully soaked, then let it stand for 10min, then add 10mL of acetonitrile and shake at 2000rpm for 2min. After freezing the centrifuge tube at -20℃ for 10min, add 4g of anhydrous magnesium sulfate, 1g of sodium chloride, 1g of sodium citrate and 0.5g of disodium hydrogen citrate in sequence, immediately shake at 2000rpm for 2min, then centrifuge at 5000rpm for 3min, collect the supernatant, which is the tobacco extract before purification.

[0064] Take 1 mL of the tobacco extract before purification in a 2 mL centrifuge tube, add 10 mg of the purification material CZIF, shake for 2 minutes and then centrifuge, filter the supernatant through a membrane, and the filtrate obtained is the purified tobacco extract.

[0065] 2.2 The obtained tobacco extract before purification and the tobacco extract after purification were detected by high performance liquid chromatography-quadrupole time-of-flight mass spectrometry. The specific detection method is as follows:

[0066] Chromatographic conditions:

[0067] Chromatographic column: Atlantis@T3 column (150mm×2.1mm×3μm, Waters, USA); column temperature: 40°C; flow rate: 0.2mL / min; injection volume: 10μL; mobile phase A: 0.1% formic acid aqueous solution (containing 5mM ammonium acetate); mobile phase B: acetonitrile; elution gradient: 0-1min, 10%-50% B; 1-5min, 50% B; 5-16min, 50%-60% B; 16-25min, 60%-80% B; 25-30min, 80%-95% B; 30-40min, 95% B; 40-40.1min, 95%-10% B; 40.1-50.1min, 10% B. All "%" involved in the chromatographic conditions are volume percentages.

[0068] Mass spectrometry conditions:

[0069] Ion source: ESI source; scanning mode: positive ion scanning; scanning range: 100-1000 m / z; spray voltage: 5500 V; nebulizer gas pressure: 55 psi; curtain gas pressure: 35 psi; auxiliary gas pressure: 50 psi; ion source temperature: 500 ° C; cluster fragmentation voltage: 40 V; collision energy: 10 eV (collision energy of primary mass spectrometry, MS), 35 eV (collision energy of secondary mass spectrometry, MS / MS); collision energy diffusion: 15 eV; detection mode: information correlation acquisition mode (intensity threshold: 10 cps; m / z range: 10-1000 Da; mass tolerance, 50 mDa; dynamic background subtraction).

[0070] The mass spectrometric response intensities of various matrix molecular species (such as pigments, alkaloids, organic acids, polyphenols, etc.) can be obtained by high performance liquid chromatography-quadrupole time-of-flight mass spectrometry, and then the purification performance A of the purification material CZIF can be quantitatively evaluated at the molecular level using the following formula:

[0071] A=(I B -I A ) / I B × 100%, where I B and I A These are the mass spectrometry response intensities of matrix molecules in tobacco extract before and after purification, respectively.

[0072] Taking pigment as an example, Figure 2 The figure shows the difference in purification ability of the purification material CZIF for lutein and β-carotene.

[0073] 3. Evaluation of matrix effect

[0074] 3.1 Accurately weigh 10.0 mg of triphenyl phosphate (TPP) standard, place it in a 10 mL volumetric flask, dilute it with acetonitrile and make up to volume, and obtain an internal standard stock solution with a concentration of 1000 μg / mL. Pipette 1.0 mL of the internal standard stock solution into a 100 mL volumetric flask, dilute it with acetonitrile and make up to volume, and obtain an internal standard solution with a concentration of 10 μg / mL. Weigh 0.01 g (accurate to 0.0001 g) of thiodicarb, pendimethalin, ethiophos sulfoxide, bisbenzimidazole, fenthion sulfoxide, phoxim, quinalphos, triadimefon, clomazone, pyraclofos, profenofos, fluazifop-butyl, indoxacarb, penconazole, hexythiazox, difenoconazole, butalin, ethion, fenamiphos, fenamiphos sulfone, methyl pirimiphos, phosalone, naproxenamide, triazophos, azoxystrobin, chlorfenapyr, ethoprophos, methidathion, prochloraz manganese salt, and tebuconazole standard substances in a 10 mL volumetric flask, dilute to volume with acetonitrile, and prepare a 1000 μg / mL single stock standard solution. Pipette 0.5 mL of the single standard stock solution of each pesticide in a 100 mL volumetric flask, dilute to volume with acetonitrile, and prepare a mixed standard working solution (5 μg / mL) of each pesticide. The mixed standard working solution with a concentration of 5 μg / mL was diluted with acetonitrile to obtain a series of standard solutions with concentrations of 2, 5, 10, 20, 50, 100 and 200 ng / mL, respectively (0.5 mL of 10 μg / mL internal standard solution was added to each volumetric flask, and the internal standard concentration was 20 ng / mL).

[0075] The above series of standard solutions were detected by high performance liquid chromatography-quadrupole time-of-flight mass spectrometry, and the detection results were subjected to linear regression analysis to obtain the slope of the solvent standard curve, as shown in Table 1. The detection conditions of high performance liquid chromatography-quadrupole time-of-flight mass spectrometry are the same as those in step 2.2.

[0076] 3.2 Weigh about 2.00g of blank tobacco sample into a 50mL stoppered centrifuge tube, add 10mL of water and shake until the sample is fully infiltrated, then let it stand for 10min, then add 10mL of acetonitrile and shake at 2000rpm for 2min. Place the centrifuge tube at -20℃ for 10min, then add 4g of anhydrous magnesium sulfate, 1g of sodium chloride, 1g of sodium citrate and 0.5g of disodium hydrogen citrate in sequence, immediately shake at 2000rpm for 2min, then centrifuge at 5000rpm for 3min, collect the supernatant, which is the tobacco extract before purification. Take 1mL of the tobacco extract before purification into a 2mL centrifuge tube, add 10mg of the purification material CZIF, shake for 2min and centrifuge, filter the supernatant through a membrane, and the filtrate is the tobacco extract after purification.

[0077] 3.3 Take 0.5 mL of the purified tobacco extract, blow it dry with nitrogen, and then reconstitute it with 0.5 mL of the series of standard solutions in step 3.1 to obtain a series of matrix-matched standard solutions with concentrations of 2, 5, 10, 20, 50, 100 and 200 ng / mL, respectively.

[0078] 3.4 The above series of matrix-matched standard solutions were detected using the same high performance liquid chromatography-quadrupole time-of-flight mass spectrometry detection method as in step 3.1, and the detection results were subjected to linear regression analysis. The results are summarized in Table 1.

[0079] 3.5 Calculate the ratio of the slope of the matrix-matched standard curve to the slope of the solvent standard curve. The results are shown in Table 1.

[0080] Table 1 Statistical table of the ratio of the slope of the matrix matching standard curve to the slope of the solvent standard curve

[0081]

[0082]

[0083] The slope ratios in Table 1 can be used to characterize the matrix effect and the actual purification ability of the purification material for the detection of specific pesticide residues. A ratio equal to 1 indicates no matrix effect, and the more it deviates from 1, the more serious the matrix effect. On the one hand, the slope ratio can directly feedback the matrix effect of the specific pesticide residue detection after purification by the QuEChERS purification material, and on the other hand, the difference in purification performance of the QuEChERS purification material can be evaluated by comparing the slope ratios when using different QuEChERS purification materials.

[0084] Example 2

[0085] The method for characterizing the purification performance of the purification material for pesticide residue detection in this embodiment uses an equal amount of purification material PSA to replace the purification material ZIF in Example 1, and then evaluates the overall level, molecular level and matrix effect level in the same manner as Example 1.

[0086] Example 3

[0087] The method for characterizing the purification performance of the purification material for pesticide residue detection in this embodiment uses an equal amount of purification material GCB to replace the purification material ZIF in Example 1, and then evaluates the overall level, molecular level and matrix effect level in the same manner as Example 1.

[0088] Example 4

[0089] The method for characterizing the purification performance of the purification material for pesticide residue detection in this embodiment uses an equal amount of purification material C18 to replace the purification material ZIF in Example 1, and then evaluates the overall level, molecular level and matrix effect level in the same manner as Example 1.

[0090] The evaluation results of the purification materials of Examples 1 to 4 at the overall level are as follows: Figure 1 shown.

[0091] Depend on Figure 1 It can be seen that in the tobacco matrix, when CZIF, PSA, C18 and GCB are used as QuEChERS purification materials, the amount of extraction matrix is ​​31.1, 42.6, 47.6 and 49.8 mg / g respectively. According to the principle that the lower the amount of extraction matrix, the better the overall purification effect of the QuEChERS purification material, the purification performance of the four QuEChERS purification materials is from strong to weak in the order of CZIF>PSA>C18>GCB. In other matrices, such as tea, spinach, etc., the overall purification performance of the above four purification materials can be determined in the same way.

[0092] The evaluation results of the purification materials of Examples 1 to 4 at the molecular level are as follows: Figure 2 shown.

[0093] Targeting pigment matrix molecules, Figure 2 It can be seen that the purification abilities of the four purification materials for lutein and β-carotene vary greatly.

[0094] According to the matrix molecules: 1) The four purification materials all have a certain purification capacity for lutein, about 11% to 36%, which is in line with the overall trend of C18≈GCB>CZIF>PSA; 2) For β-carotene, the four purification materials all have a certain purification capacity, about 20% to 76%, which is in line with the overall trend of CZIF>GCB>C18>PSA.

[0095] In terms of purification materials: CZIF, PSA, and GCB have better purification abilities for β-carotene than for lutein, while C18 has comparable purification abilities for lutein and β-carotene.

[0096] For other target matrix molecules or matrix molecules of interest, such as alkaloids, polyphenols, organic acids, sulfur-containing compounds, etc., quantitative evaluation can be carried out separately in the above manner to clarify the purification performance of different purification materials for different matrix molecules.

[0097] The evaluation results of the purification materials of Examples 1 to 4 at the matrix effect level are summarized in Table 1 above.

[0098] It can be seen from the data in Table 1 that for disulfothion sulfoxide, the purification performance of the four QuEChERS purification materials cannot effectively reduce the influence of the matrix effect on the detection of disulfothion sulfoxide in tobacco. Nevertheless, from the perspective of reducing the matrix effect in the detection of disulfothion sulfoxide in tobacco, the purification performance of the four QuEChERS purification materials is GCB>PSA≈C18>CZIF from strong to weak.

[0099] For pendimethalin, after purification by the four QuEChERS purification materials, the matrix effect in the detection of pendimethalin in tobacco was relatively small. From the perspective of reducing the matrix effect in the detection of pendimethalin in tobacco, the purification performance of the four QuEChERS purification materials is PSA>C18>CZIF>GCB from strong to weak.

[0100] For phosalone, after purification by four QuEChERS purification materials, the matrix effect in the detection of phosalone in tobacco was relatively small. From the perspective of reducing the matrix effect in the detection of phosalone in tobacco, the purification performance of the four QuEChERS purification materials is CZIF>PSA>GCB>C18 from strong to weak.

[0101] 2. Specific examples of application of the above characterization method in purification material screening

[0102] Example 5

[0103] The above characterization method demonstrates the characteristic properties related to the multi-dimensional purification performance of different purification materials, which can provide a basis for the rapid and effective screening of QuEChERS purification materials. The following is a detailed explanation using a simulation example.

[0104] The six QuEChERS purification materials were respectively designated as A, B, C, D, E, and F. The samples were respectively set as tobacco (complex matrix, relatively high alkaloid content), tea (high polyphenol content), spinach (high pigment content), grape (low pigment content), citrus (high organic acid content), and onion (rich in sulfur compounds). The detected pesticide residues were respectively set as thiodicarb, pendimethalin, disulfothion sulfoxide, bisbenzimidazole, fenthion sulfoxide, and phoxim. The evaluations were performed at the overall level, molecular level, and matrix effect level in the manner of Example 1.

[0105] The overall evaluation results of the six purification materials for different sample matrices are listed in Table 2.

[0106] Table 2 Overall evaluation results of different purification materials

[0107] Serial number Sample Type Purification capacity order 1 tobacco A>B>C>D>E>F 2 tea C>D>E>F>B>A 3 spinach E>F>B>A>C>D 4 Grape F>A>B>C>D>E 5 Tangerine D>E>F>B>A>C 6 onion B>A>E>F>C>D

[0108] Taking tobacco leaf matrix as an example, the evaluation results of different purification materials for matrix molecules are shown in Table 3. Similar evaluation results can also be obtained for other sample matrices.

[0109] Table 3 Evaluation results for different matrix molecules

[0110] Serial number Matrix molecules Purification capacity order 1 Alkaloids A>C>F>B>D>E 2 Polyphenols C>D>E>F>B>A 3 pigment E>B>A>F>C>D 4 Organic Acid D>C>B>A>E>F 5 Sulfur compounds B>E>F>D>C>A

[0111] Taking tobacco leaf matrix as an example, the purification ability of different materials for pesticide residues is ranked as shown in Table 4. Similar evaluation results can also be obtained for other sample matrices.

[0112] Table 4 Ranking results of purification capacity for different pesticide residues

[0113] Serial number Detection of pesticide residues Purification capacity order 1 Thiodicarb A>B>D>E>C>F 2 Pendimethalin C>D>B>A>E>F 3 Disulfothion sulfoxide D>F>C>E>B>A 4 Bistriazole E>F>C>B>A>D 5 Fenthion sulfoxide F>A>C>B>E>D 6 Phoxim B>A>F>D>E>C

[0114] According to the above evaluation results of the multi-dimensional purification performance characteristic attributes of the six purification materials, if thiodicarb in tobacco samples is detected, considering that purification material A has the best overall purification effect on the tobacco matrix and the best matrix effect when reducing thiodicarb detection, purification material A is preferred. On this basis, according to the evaluation results at the molecular level, purification material A has the best purification effect on the main matrix alkaloids in tobacco, and the worst purification effect on polyphenols and sulfur-containing compounds. In order to further optimize the thiodicarb detection effect, considering that polyphenols are also the main matrix in tobacco, and the content of sulfur-containing compounds is extremely low, and purification material C has the best purification effect on polyphenols, while purification material B has the best purification effect on sulfur-containing compounds, the purification material combination strategy that can be considered is to use purification materials A and C together to achieve effective purification of polyphenols simultaneously, and purification materials A and B should not be used together.

[0115] If pendimethalin is detected in tobacco samples, considering that purification material A has the best overall purification effect on the tobacco matrix, and purification material C is the best at reducing the matrix effect when detecting pendimethalin, the combined use of purification materials A and C can be considered. On this basis, according to the evaluation results at the molecular level, purification material A has the best purification effect on the main matrix alkaloids in tobacco, while purification material C has the best purification effect on the main matrix polyphenols in tobacco. The combined use of the two can achieve efficient purification of alkaloids and polyphenols; in addition, although purification materials A and C can achieve the purification of pigments and organic acids, two tobacco matrices, to a certain extent, their purification effects are not as good as those of purification materials E and D. In order to further optimize the detection effect of thiodicarb, a strategy that can be further optimized is to use purification materials A and C in combination with one or both of E and D.

[0116] When detecting the corresponding pesticide residue molecules in other sample matrices, similar strategies can be used to rank the purification capabilities of each purification material at the overall level, molecular level, and matrix effect level, thereby achieving rapid selection and combination of purification materials. In addition, based on the selection and combination results of purification materials, new QuEChERS purification materials can be constructed in combination with the structural and functional group characteristics of the purification materials, thereby improving the effectiveness and pertinence of pesticide residue detection analysis.

[0117] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for characterizing the purification performance of a purification material for pesticide residue detection, characterized in that: This includes evaluating the purification performance of purification materials at the overall level, molecular level, and matrix effect level: The overall level evaluation includes determining the weight of the evaporation residue before and after the extraction liquid is purified, and evaluating the overall purification capacity based on the weight of the evaporation residue; The molecular level evaluation includes determining the mass spectrometry response intensity for different matrix molecule types before and after the extraction solution is purified, and evaluating the purification ability of the purification material for the corresponding matrix molecules according to the degree of decrease in the mass spectrometry response intensity; The evaluation at the matrix effect level is aimed at pesticide residue detection, including performing linear regression analysis on the pesticide residue standard solution to obtain the slope of the solvent standard curve; using the purification material to purify the blank sample that does not contain the pesticide residue to be detected, and then using the pesticide residue standard solution to prepare a matrix matching standard solution, and performing linear regression analysis on the matrix matching standard solution to obtain the slope of the matrix matching standard curve; The ratio of the slope of the matrix matching standard curve to the slope of the solvent standard curve is calculated, and the purification ability of the purification material for pesticide residues is evaluated by the ratio.

2. The method for characterizing the purification performance of the purification material for pesticide residue detection according to claim 1, characterized in that: The mass spectrometry response intensity is obtained by respectively performing liquid chromatography-high resolution mass spectrometry detection on the extract before and after purification.

3. The method for characterizing the purification performance of the purification material for pesticide residue detection according to claim 2, characterized in that: The chromatographic conditions of the liquid chromatography-high resolution mass spectrometry are as follows: chromatographic column: Atlantis@T3 column; mobile phase A: 5 mM ammonium acetate aqueous solution with 0.1% formic acid; mobile phase B: acetonitrile; gradient elution, elution gradient: 0-1 min, 10%-50% B; 1-5 min, 50% B; 5-16 min, 50%-60% B; 16-25 min, 60%-80% B; 25-30 min, 80%-95% B; 30-40 min, 95% B; 40~40.1min, 95%~10%B; 40.1~50.1min, 10%B; The mass spectrometry conditions were as follows: ESI source; scanning mode: positive ion scanning; scanning range: 100-1000 m / z; spray voltage: 5500 V; nebulizer gas pressure: 55 psi; curtain gas pressure: 35 psi; Auxiliary gas pressure: 50 psi; ion source temperature: 500 °C; cluster fragmentation voltage: 40 V; collision energy spread: 15 eV; Detection mode: information association collection mode.

4. The method for characterizing the purification performance of the purification material for pesticide residue detection according to claim 1, characterized in that: In the molecular level evaluation, the purification ability of the purification material on the corresponding matrix molecules is quantified as follows: A=(I B -I A ) / I B ×100% In the formula, I B and I A are the mass spectrometric response intensities of matrix molecules in the extract before and after purification, respectively.

5. The method for characterizing the purification performance of a purification material for pesticide residue detection according to claim 1 or 4, characterized in that: In the molecular level evaluation, the matrix molecule types include one or more of alkaloids, polyphenols, pigments, organic acids, and sulfur-containing compounds.

6. The method for characterizing the purification performance of a purification material for pesticide residue detection according to claim 1, characterized in that: In the evaluation of the matrix effect level, a ratio equal to 1 indicates the best purification ability, and a deviation from 1 indicates a worse purification ability.

7. The method for characterizing the purification performance of a purification material for pesticide residue detection according to claim 1, characterized in that: In the evaluation at the matrix effect level, the pesticide residues to be detected include one or more of thiodicarb, pendimethalin, ethophos sulfoxide, bisbenzimidazole, fenthion sulfoxide, phoxim, quinalphos, triadimefon, isothiocarb, pyraclostrobin, profenofos, fluazifop-butyl, indoxacarb, penconazole, hexathiachlor, difenoconazole, butalin, ethophos, fenamiphos, fenamiphos sulfone, methyl pirimiphos, phosalone, pyrifos, triazophos, azophos, chlorfenapyr, ethophos, chlorfenapyr, thiophanate-methyl, chlorfenapyr, triazophos, azophos, chlorfenapyr, ethophos, methidathion, manganese salt of prochloraz, and tebuconazole.

8. The method for characterizing the purification performance of a purification material for pesticide residue detection according to claim 1, characterized in that: In the evaluation at the matrix effect level, the purification treatment includes extracting the blank sample with a solvent to obtain an extract, mixing the purification material with the extract, and then performing solid-liquid separation to obtain a purified extract.

9. Use of the method for characterizing the purification performance of a purification material for pesticide residue detection as claimed in any one of claims 1 to 8 in the screening of purification materials.

10. The use according to claim 9, characterized in that The purification capabilities of different purification materials are ranked at the overall level, molecular level and matrix effect level, and the purification materials are selected or combined according to the type of matrix and the pesticide residues to be detected.

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