Preparation method of solid phase extraction filler special for organophosphorus insecticide

Abstract

The application discloses a preparation method of a solid-phase extraction filler special for organic phosphorus insecticides, and belongs to the technical field of analysis and detection. The solid-phase extraction filler special for organic phosphorus insecticides is prepared by the following steps: firstly, modifying a template molecular composition to form a polymerizable monomer, then bonding the polymerizable monomer into a cross-linked polymer, and finally removing the template molecular composition by hydrolysis to obtain the solid-phase extraction filler special for organic phosphorus insecticides. The solid-phase extraction filler special for organic phosphorus insecticides has the advantages of good specific adsorption to organic phosphorus insecticide molecules, high detection sensitivity, complete impurity removal, good filler stability, high strength, strong chemical resistance, and the like. Meanwhile, the template molecular composition does not belong to the molecules to be detected, and a small amount of residual template molecular composition does not affect detection.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of analytical detection, and particularly relates to a preparation method of a solid-phase extraction filler special for organic phosphorus insecticides. BACKGROUND

[0002] Organic phosphorus insecticides are a kind of insecticides commonly used in agriculture and are widely used for preventing and treating plant diseases and insect pests in the world. The main toxicity of organic phosphorus insecticides to humans and animals is caused by the inhibition of acetylcholinesterase and leads to neurotoxicity. Some organic phosphorus insecticides belong to high-toxicity insecticides, and thus it is crucial to detect organic phosphorus insecticides in food and agricultural products.

[0003] In order to monitor and regulate the use of organic phosphorus insecticides and reduce the harm of organic phosphorus insecticides to humans, animals and the environment, a large amount of work has been done by technical personnel, and various standard methods for detecting organic phosphorus insecticide residues have been developed. For example, the method for determining 90 kinds of organic phosphorus pesticides and their metabolites in plant-derived foods by gas chromatography is specified in the GB23200.116-2019 National Food Safety Standard for Determining Residues of 90 Kinds of Organic Phosphorus Pesticides and Their Metabolites in Plant-Derived Foods.

[0004] In the prior art, the disclosure number CN112730672A discloses a rapid determination method for the residual amount of organic phosphorus pesticides in soil. The method specifically discloses a method of connecting a C18 solid-phase extraction column and an HLB solid-phase extraction column in series to purify the extraction liquid, and then performing elution and concentration, and determining by gas chromatography-electron capture detector. However, this method has a high cost. Since the performances of the two solid-phase extraction columns are completely different, two kinds of elution liquids need to be used for elution, the steps are complicated, the detection period is long, and the elution capacities of the two kinds of elution liquids in the different solid-phase extraction columns are different, so some target substances may not be completely eluted, resulting in a low detection value.

[0005] The patent number CN104209103A discloses a preparation method and application of a fenthion molecularly imprinted solid-phase extraction column. The method specifically discloses that fenthion is used as a template, the fenthion is dissolved in a porogen, a functional monomer is added, and pre-polymerization is performed at low temperature. Then, a crosslinking agent and an initiator are added, the mixed liquid is dropped into a previously prepared polyvinyl alcohol solution, and a fenthion molecularly imprinted polymer microsphere is prepared by using a suspension polymerization method. After the obtained polymer microspheres are subjected to a series of treatments such as rinsing, sieving and drying, the wet method is used to fill the solid-phase extraction column empty column tube, and after one-time rinsing with acetone and methanol, the solid-phase extraction column is used for selective adsorption, enrichment and purification of residual fenthion in food. However, the present application uses a template pesticide molecule as a template, and the trace residues of the template molecule in the molecularly imprinted polymer may seriously affect the detection results. At the same time, a small amount of molecularly imprinted cavities exist in the interior of the polymer microspheres, diffusion is slow, elution is difficult, and the detection results may be adversely affected.

[0006] Patent No. CN103399099A discloses a method for simultaneously detecting nine kinds of organophosphorus pesticides, which specifically discloses the preparation of a multi-recognition site molecular imprinting polymer, the establishment of a molecular imprinting matrix solid phase dispersion extraction and gas chromatography system, and the like. The invention prepares a common template 4-dimethoxythiophosphamide butyric acid, which has high selective recognition performance for nine kinds of pesticides such as trichlorphon, and then uses the common template as a porogen to prepare a molecular imprinting polymer, thereby avoiding the shortcomings of traditional molecular imprinting polymers, such as recognizing a single substance. The molecular imprinting matrix solid phase dispersion extraction is combined with gas chromatography to establish a rapid and sensitive detection method with a wide detection range for trace amounts of nine kinds of organophosphorus pesticides such as trichlorphon. However, the polymer prepared by the method needs to be ground before use, and the irregular appearance may cause different solid phase extraction efficiencies. In addition, a small amount of molecular imprinting cavities exist inside the polymer microspheres, which have slow diffusion and difficult elution, and may adversely affect the detection results.

[0007] The existing detection method has the following problems: 1. The headspace sampling port of the gas chromatograph often accumulates a large amount of solid impurities such as pigments, which needs to be cleaned frequently, seriously affecting the detection period and detection effect; 2. Some polymers need to be ground before use, and the irregular appearance may cause different solid phase extraction efficiencies. In addition, a small amount of molecular imprinting cavities exist inside the polymer microspheres, which have slow diffusion and difficult elution, and may adversely affect the detection results. SUMMARY

[0008] The application provides a preparation method of a solid phase extraction filler special for organophosphorus insecticides, which comprises the following steps: modifying a template molecule composition into a polymerizable monomer, bonding the polymerizable monomer into a cross-linked polymer, and then hydrolyzing and removing the template molecule composition to obtain the solid phase extraction filler special for organophosphorus insecticides.

[0009] The technical scheme of the application is as follows:

[0010] A preparation method of a solid phase extraction filler special for organophosphorus insecticides, comprising the following steps:

[0011] S1, 16.7-24.7 parts of substituted hydroxy aniline is added into a reaction kettle, 14.1-15.5 parts of alkenyl isocyanate is slowly added dropwise within 1-2 hours, stirred uniformly, 0.04-0.06 parts of polyurethane catalyst is added at 45-55℃, reacted for 2-4 hours; 27.8 parts of 3-(2,3-epoxypropoxy) propyl triethoxysilane is continuously added, stirred for 0.5 hours, 0.1-0.2 parts of epoxy catalyst is added, heated to 50-60℃, reacted for 2-3 hours; cooled to 20-30℃, 30-35 parts of saturated sodium bicarbonate aqueous solution is added, the epoxy catalyst is removed by shaking, the organic phase is washed with 300 parts of deionized water for 3 times, the water phase is discarded; the organic phase is dried with 4A molecular sieve, to obtain a reactive template molecular composition;

[0012] S2, 100 parts of styrene, 4-9 parts of crosslinking agent and 0.5-1.2 parts of initiator are mixed and dissolved uniformly to obtain an oil phase A; 6-9 parts of the reactive template molecular composition, 10-15 parts of styrene, 10-15 parts of crosslinking agent and 10-15 parts of vinyl acetate are mixed and dissolved uniformly, 30-40 parts of 0.25% sodium dodecyl sulfate aqueous solution is added, stirred at 800-1000 rpm for 0.5-1 hour to obtain an oil phase B; 4-6 parts of polyvinyl alcohol 1788 and 10-15 parts of sodium chloride are dissolved in 400-500 parts of deionized water, the oil phase A is added, stirred at 1200-1500 rpm and heated to 60-70℃, after being kept for 2-3 hours, the oil phase B is added dropwise into the reaction kettle within 2-4 hours; after the dropwise addition is completed, it is kept for 3-5 hours, cooled to 20-30℃; the microspheres are washed with 300 parts of deionized water for 3 times, dried at 60℃ and sieved, 400-1000 mesh microspheres are taken to obtain crosslinked polymer microspheres;

[0013] S3, 10 parts of the polymer microspheres is added into 160-180 parts of 24% sodium hydroxide solution, heated to 90-100℃, reacted for 3-5 hours, then cooled to 20-30℃, washed with deionized water until neutral, extracted with 400 parts of a mixed solvent of ethanol, toluene and acetic acid under boiling conditions for 10-12 hours, and the microspheres are washed with 200 parts of ethanol, vacuum dried at 60℃ to obtain a solid phase extraction filler special for organophosphorus insecticide.

[0014] Further, the substituted hydroxy aniline in step S1 is a combination of at least two of 3'-(3-hydroxyphenyl) aniline, 4'-(4-hydroxyphenyl) aniline, 5-bromo-4-fluoro-2-hydroxy aniline, 2-chloro-4-methyl-3-hydroxy aniline, 2-nitro-4-hydroxy aniline, 4-amino-2,6-dichloro-5-fluoro phenol, 4-amino-2,6-dichlorophenol and 4-amino-2,6-dibromo phenol.

[0015] Further, the alkenyl isocyanate in step S1 is one of 2-isocyanatoethyl acrylate and 2-isocyanatoethyl methacrylate.

[0016] Further, the polyurethane catalyst in step S1 is an organic bismuth catalyst, preferably DY-20 of Shanghai Deyin Chemical Co., Ltd., and Kain Chemical Co., Ltd. 8108 and 8106.

[0017] Further, the epoxy catalyst in step S1 is boron trifluoride etherate.

[0018] Further, the crosslinking agent in step S2 is one or a combination of 80% divinylbenzene, N-methyldiallylamine, and ethylene glycol diallyl ether.

[0019] Further, the initiator in step S2 is one of dodecanoyl peroxide and azobisisobutyronitrile.

[0020] Further, the volume ratio of the mixed solvent of ethanol, toluene, and acetic acid in step S3 is 2:8:1.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] 1. The solid-phase extraction filler special for organophosphorus insecticides in the present application is prepared by the following steps: firstly, the isocyanate group in the alkenyl isocyanate reacts with the amine group of the substituted aniline under the catalysis of a polyurethane catalyst to obtain a compound containing a hydroxyl group and a double bond; the hydroxyl group in the compound further undergoes ring-opening reaction with the epoxy group in 3-(2,3-epoxypropoxy) propyl triethoxysilane under the catalysis of an epoxy catalyst to obtain a reaction-type modified template molecule composition; the reaction-type modified template molecule composition, styrene, vinyl acetate, and a crosslinking agent are subjected to seed secondary copolymerization on the basis of low-crosslinking microspheres prepared in advance by a suspension polymerization method to obtain core-shell structure crosslinked polymer microspheres; then, the ester group, carbamic acid group, etc. in the crosslinked polymer microspheres are hydrolyzed by using a strong alkali solution at high temperature, and the template molecule composition is removed by solvent extraction and cleaning to obtain polymer microspheres special for organophosphorus insecticides.

[0023] 2、The organic phosphorus insecticide special solid phase extraction filler of the application, the cavity volume formed finally after the hydrolysis of the molecule after the reaction of alkenyl isocyanate, polyurethane catalyst, 3-(2,3-epoxypropoxy) propyl triethoxysilane and other compounds in the polymer and the volume and form of the organic phosphorus insecticide are relatively similar, the principle of molecular imprinting can be used to retain the organic phosphorus insecticide in the cavity, so that the organic phosphorus insecticide and impurities are separated, in the residual detection process, the target object can be adsorbed under the premise of guaranteeing, the impurities are washed away fully, and a small amount of eluent can be used for complete elution, solvent consumption is reduced, and the detection period is shortened, the template molecule does not belong to the detected molecule, the polymer forms a cavity after alkaline hydrolysis and solvent extraction, and incomplete extraction does not affect detection.

[0024] 3、The organic phosphorus insecticide special solid phase extraction filler of the application has good specificity for the organic phosphorus insecticide, impurities are completely removed, the detection sensitivity is high, the instrument is less affected, and the maintenance period of the instrument is prolonged. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a scanning electron microscope graph of the organic phosphorus insecticide special solid phase extraction filler of example 1;

[0026] Figure 2 It is a chromatogram and recovery concentration data of dichlorvos, malathion and chlorpyrifos in sample 8;

[0027] Figure 3 It is an appearance graph of the on-machine liquid after purification of sample 7-25. DETAILED DESCRIPTION

[0028] The application will be further described below in combination with preferred embodiments, and the endpoints and any values disclosed in the application are not limited to the exact range or value, and the ranges or values should be understood as containing values close to the ranges or values; for numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be regarded as being specifically disclosed herein.

[0029] The materials, reagents and the like used in the following examples are commercially available unless otherwise specified;

[0030] The experimental methods in the following examples are conventional methods unless otherwise specified.

[0031] A preparation method of an organic phosphorus insecticide special solid phase extraction filler, comprising the following steps:

[0032] S1, 16.7-24.7 parts of substituted hydroxy aniline is added into a reaction kettle, 14.1-15.5 parts of alkenyl isocyanate is slowly added dropwise within 1-2 hours, stirred uniformly, 0.04-0.06 parts of polyurethane catalyst is added at 45-55℃, reacted for 2-4 hours; 27.8 parts of 3-(2,3-epoxypropoxy) propyl triethoxysilane is continuously added, stirred for 0.5 hours, 0.1-0.2 parts of epoxy catalyst is added, heated to 50-60℃, reacted for 2-3 hours; cooled to 20-30℃, 30-35 parts of saturated sodium bicarbonate aqueous solution is added, the epoxy catalyst is removed by shaking, the organic phase is washed with 300 parts of deionized water for 3 times, and the water phase is discarded; the organic phase is dried with 4A molecular sieve, and a reaction type template molecular composition is obtained;

[0033] S2, 100 parts of styrene, 4-9 parts of crosslinking agent and 0.5-1.2 parts of initiator are mixed and dissolved uniformly to obtain oil phase A; 6-9 parts of reaction type template molecular composition, 10-15 parts of styrene, 10-15 parts of crosslinking agent and 10-15 parts of vinyl acetate are mixed and dissolved uniformly, 30-40 parts of 0.25% sodium dodecyl sulfate aqueous solution is added, stirred at 800-1000 rpm for 0.5-1 hour to obtain oil phase B; 4-6 parts of polyvinyl alcohol 1788 and 10-15 parts of sodium chloride are dissolved in 400-500 parts of deionized water, oil phase A is added, stirred at 1200-1500 rpm and heated to 60-70℃, and after being kept for 2-3 hours, oil phase B is added dropwise into the reaction kettle within 2-4 hours; after the dropwise addition is completed, it is kept for 3-5 hours, and cooled to 20-30℃; the microspheres are washed with 300 parts of deionized water for 3 times, dried at 60℃, and sieved, 400-1000 mesh microspheres are taken, and crosslinked polymer microspheres are obtained.

[0034] S3, 10 parts of polymer microspheres are added into 160-180 parts of 24% sodium hydroxide solution, heated to 90-100℃, reacted for 3-5 hours, cooled to 20-30℃, washed with deionized water until neutral, extracted with 400 parts of a mixed solvent of ethanol, toluene and acetic acid under boiling conditions for 10-12 hours, and the microspheres are washed with 200 parts of ethanol, and vacuum dried at 60℃ to obtain an organic phosphorus insecticide special solid phase extraction filler.

[0035] Example 1

[0036] A preparation method of an organic phosphorus insecticide special solid phase extraction filler, comprising the following steps:

[0037] S1, 5.4g 3'-(3-hydroxyphenyl) aniline, 5.2g 5-bromo-4-fluoro-2-hydroxy aniline, 6.7g 4-amino-2,6-dibromophenol and 4.8g 4-amino-2,6-dichloro-5-fluorophenol were added into a reaction kettle, 14.1g 2-isocyanatoethyl acrylate was slowly added dropwise within 2 hours, stirred uniformly, 0.04g polyurethane catalyst was added at 45℃ 8108, reaction for 4 hours; continue to add 27.8g 3-(2,3-epoxypropoxy) propyl triethoxysilane, after stirring for 0.5 hours, add 0.1g epoxy catalyst boron trifluoride ether, warm up to 60℃, react for 2 hours; cool down to 30℃, add 30g saturated sodium bicarbonate aqueous solution, shake to remove the epoxy catalyst, wash the organic phase with 300g deionized water for 3 times, discard the aqueous phase; dry the organic phase with 4A molecular sieve, to obtain the reactive template molecular composition.

[0038] S2, 100g styrene, 4g crosslinking agent 80% divinyl benzene and 0.5g initiator azobisisobutyronitrile were mixed and dissolved uniformly to obtain oil phase A; 6g reactive template molecular composition, 15g styrene, 10g crosslinking agent 80% divinyl benzene and 15g vinyl acetate were mixed and dissolved uniformly, add 30g 0.25% sodium dodecyl sulfate aqueous solution, stir at 1000rpm for 0.5 hours to obtain oil phase B; 6g polyvinyl alcohol 1788 and 15g sodium chloride were dissolved in 500g deionized water, add oil phase A, stir at 1200rpm and warm up to 60℃, keep for 3 hours, then add oil phase B dropwise into the reaction kettle within 4 hours; keep for 5 hours after the dropwise addition is completed, cool down to 20℃; wash the microspheres with 300g deionized water for 3 times, dry at 60℃ and sieve, take 400-1000 mesh microspheres to obtain crosslinked polymer microspheres;

[0039] S3, 10g polymer microspheres were added into 160g 24% sodium hydroxide solution, warm up to 100℃, react for 3 hours, then cool down to 30℃, wash to neutral with deionized water, extract with 400g mixed solvent of ethanol, toluene and acetic acid under boiling conditions for 10 hours, wherein the volume ratio of ethanol, toluene and acetic acid in the mixed solvent is 2:8:1, wash the microspheres with 200g ethanol, vacuum dry at 60℃ to obtain the solid phase extraction filler special for organophosphorus insecticide, the scanning electron microscope image of the appearance of the solid phase extraction filler special for organophosphorus insecticide is shown in Figure 1 .

[0040] Example 2:

[0041] A preparation method of a solid phase extraction filler special for organophosphorus insecticide, comprising the following steps:

[0042] S1, 5.3g 4'-(4-hydroxyphenyl) aniline, 3.9g 2-chloro-4-methyl-3-hydroxy aniline, 3.8g 2-nitro-4-hydroxy aniline and 4.5g 4-amino-2,6-dichlorophenol were added into a reaction kettle, 15.5g 2-isocyanatoethyl methacrylate was slowly added dropwise within 1 hour, stirred uniformly, 0.06g polyurethane catalyst was added at 55°C 8106, reaction for 2 hours; continue to add 27.8g 3-(2,3-epoxypropoxy) propyl triethoxysilane, after stirring for 0.5 hours, add 0.2g epoxy catalyst boron trifluoride ether, warm up to 50°C, reaction for 3 hours; cool down to 20°C, add 35g saturated sodium bicarbonate aqueous solution, shake to remove the epoxy catalyst, wash the organic phase with 300g deionized water for 3 times, discard the aqueous phase; dry the organic phase with 4A molecular sieve, to obtain the reactive template molecular composition;

[0043] S2, 100g styrene, 6g crosslinking agent N-methyl diallyl amine and 1g initiator dodecanoyl peroxide were mixed and dissolved uniformly to obtain oil phase A; 9g reactive template molecular composition, 10g styrene, 15g crosslinking agent N-methyl diallyl amine and 10g vinyl acetate were mixed and dissolved uniformly, add 30g 0.25% sodium dodecyl sulfate aqueous solution, stir at 800rpm for 1 hour to obtain oil phase B; 4g polyvinyl alcohol 1788 and 10g sodium chloride were dissolved in 400g deionized water, add oil phase A, stir at 1500rpm and warm up to 70°C, keep warm for 2 hours, then add oil phase B dropwise into the reaction kettle within 2 hours; keep warm for 3 hours after the dropwise addition is completed, cool down to 25°C; wash the microspheres with 300g deionized water for 3 times, dry at 60°C and sieve, take 400-1000 mesh microspheres to obtain crosslinked polymer microspheres;

[0044] S3, 10g polymer microspheres were added into 180g 24% sodium hydroxide solution, warm up to 90°C, reaction for 5 hours, then cool down to 25°C, wash to neutral with deionized water, extract with 400g mixed solvent of ethanol, toluene and acetic acid under boiling conditions for 12 hours, wherein the volume ratio of ethanol, toluene and acetic acid in the mixed solvent is 2:8:1, and wash the microspheres with 200g ethanol, vacuum dry at 60°C to obtain the solid phase extraction filler special for organophosphorus insecticide.

[0045] Example 3:

[0046] A preparation method of a solid phase extraction filler special for organophosphorus insecticide, comprising the following steps:

[0047] S1, 8.7 g of 3'-(3-hydroxyphenyl) aniline and 16 g of 4-amino-2,6-dibromo phenol were added to a reaction kettle, 15.5 g of 2-isocyanatoethyl methacrylate was slowly added dropwise within 1 hour, stirred uniformly, 0.05 g of polyurethane catalyst was added at 50 °C 8106, reaction for 3 hours; continue to add 27.8 g of 3-(2,3-epoxypropoxy) propyl triethoxysilane, after stirring for 0.5 hours, add 0.16 g of epoxy catalyst boron trifluoride ether, warm up to 53 °C, reaction for 3 hours; cool down to 25 °C, add 33 g of saturated sodium bicarbonate aqueous solution, shake to remove the epoxy catalyst, wash the organic phase with 300 g of deionized water for 3 times, discard the aqueous phase; dry the organic phase with 4A molecular sieve, to obtain a reactive template molecular composition;

[0048] S2, 100 g of styrene, 9 g of crosslinking agent ethylene glycol diallyl ether and 1.2 g of initiator dodecanoyl peroxide were mixed and dissolved uniformly to obtain oil phase A; 8 g of the reactive template molecular composition, 12 g of styrene, 15 g of crosslinking agent ethylene glycol diallyl ether and 13 g of vinyl acetate were mixed and dissolved uniformly, 35 g of 0.25% sodium dodecyl sulfate aqueous solution was added, stirred at 900 rpm for 1 hour to obtain oil phase B; 5 g of polyvinyl alcohol 1788 and 13 g of sodium chloride were dissolved in 4300 g of deionized water, oil phase A was added, stirred at 1300 rpm and warmed up to 66 °C, after keeping for 2.5 hours, oil phase B was added dropwise into the reaction kettle within 3 hours; after the dropwise addition was completed, keep for 4 hours, cool down to 25 °C; wash the microspheres with 300 g of deionized water for 3 times, dry at 60 °C and sieve, take the 400-1000 mesh microspheres to obtain crosslinked polymer microspheres;

[0049] S3, 10 g of the polymer microspheres were added into 170 g of 24% sodium hydroxide solution, warmed up to 95 °C, after reaction for 4 hours, cool down to 20 °C, washed with deionized water until neutral, extracted with 400 g of mixed solvent of ethanol, toluene and acetic acid under boiling conditions for 11 hours, wherein the volume ratio of ethanol, toluene and acetic acid in the mixed solvent is 2:8:1, and the microspheres were washed with 200 g of ethanol, vacuum dried at 60 °C to obtain the solid phase extraction filler special for organophosphorus insecticide.

[0050] Example 4:

[0051] A preparation method of a solid phase extraction filler special for organophosphorus insecticide, comprising the following steps:

[0052] S1, 8.7 g of 3'-(3-hydroxyphenyl) aniline and 16 g of 4-amino-2,6-dibromo phenol were added to a reaction kettle, 15.5 g of 2-isocyanatoethyl methacrylate was slowly added dropwise within 1 hour, stirred uniformly, 0.05 g of polyurethane catalyst was added at 50 °C 8108, reaction for 3.5 hours; continue to add 27.8g 3-(2,3-epoxypropoxy) propyl triethoxysilane, after stirring for 0.5 hours, add 0.2g epoxy catalyst boron trifluoride ether, warm up to 57℃, react for 3 hours; cool down to 25℃, add 35g saturated sodium bicarbonate aqueous solution, shake to remove the epoxy catalyst, wash the organic phase with 300g deionized water for 3 times, discard the aqueous phase; dry the organic phase with 4A molecular sieve, obtain the reactive template molecular composition;

[0053] S2, mix and dissolve 100g styrene, 7g crosslinking agent 80% divinyl benzene and 0.7g initiator azobisisobutyronitrile uniformly to obtain oil phase A; mix and dissolve 7g reactive template molecular composition, 10g styrene, 11g crosslinking agent 80% divinyl benzene and 12g vinyl acetate uniformly, add 30g 0.25% sodium dodecyl sulfate aqueous solution, stir at 800rpm for 1 hour to obtain oil phase B; dissolve 4g polyvinyl alcohol 1788 and 10g sodium chloride in 400g deionized water, add oil phase A, stir at 1400rpm and warm up to 63℃, keep warm for 3 hours, then drop oil phase B into the reaction kettle in 3 hours; keep warm for 5 hours after dropping, cool down to 26℃; wash the microspheres with 300g deionized water for 3 times, dry at 60℃ and sieve, take 400-1000 mesh microspheres to obtain crosslinked polymer microspheres;

[0054] S3, add 10g polymer microspheres into 175g 24% sodium hydroxide solution, warm up to 100℃, react for 4 hours, then cool down to 20℃, wash with deionized water until neutral, extract with 400g mixed solvent of ethanol, toluene and acetic acid (volume ratio 2:8:1) under boiling conditions for 10 hours, and wash the microspheres with 200g ethanol, vacuum dry at 60℃ to obtain the solid phase extraction filler special for organophosphorus insecticide.

[0055] Comparative Example 1:

[0056] The difference between Comparative Example 1 and Example 1 is that: Comparative Example 1 does not use reactive template molecular composition, and equal amount of styrene is used instead of reactive template molecular composition, and the rest of the raw materials and preparation process are the same as those of Example 1, and the preparation method comprises the following steps:

[0057] S1. Mix and dissolve 100g styrene, 4g crosslinking agent 80% divinylbenzene, and 0.5g initiator azobisisobutyronitrile to obtain oil phase A; mix and dissolve 21g styrene, 10g crosslinking agent 80% divinylbenzene, and 15g vinyl acetate to obtain oil phase B; add 30g 0.25% sodium dodecyl sulfate aqueous solution and stir at 1000rpm for 0.5 hours to obtain oil phase B; dissolve 6g polyvinyl alcohol 1788 and 15g sodium chloride in 500g deionized water, add oil phase A, stir at 1200rpm and heat to 60℃, keep at this temperature for 3 hours, then add oil phase B dropwise to the reactor over 4 hours; keep at this temperature for 5 hours after the addition is complete, then cool to 20℃; wash the microspheres three times with 300g deionized water, dry at 60℃ and sieve, taking 400-1000 mesh microspheres to obtain crosslinked polymer microspheres;

[0058] S2. Add 10g of polymer microspheres to 160g of 24% sodium hydroxide solution, heat to 100℃, react for 3 hours, cool to 30℃, wash with deionized water until neutral, extract with a mixed solvent of 400g of ethanol, toluene and acetic acid in a volume ratio of 2:8:1 under boiling conditions for 10 hours, wash the microspheres with 200g of ethanol, and vacuum dry at 60℃ to obtain the comparative solid phase extraction packing.

[0059] Example 5:

[0060] Comparative tests were conducted using the organophosphorus insecticide-specific solid-phase extraction packing material of Example 1 of this invention, the comparative solid-phase extraction packing material of Comparative Example 1, and a conventional solid-phase extraction column. The pretreatment and instrument conditions for the comparative tests are described below:

[0061] Preparation of a solid-phase extraction column for organophosphorus pesticides: The solid-phase extraction packing material for organophosphorus pesticides prepared in Example 1 consists of spherical polydisperse particles with a very small amount of fragments. Its regular morphology is advantageous for the adsorption and elution of the target analyte during detection. A scanning electron microscope image of the solid-phase extraction packing material for organophosphorus pesticides prepared in Example 1 is shown below. Figure 1 As shown. Weigh 500 mg of the organophosphorus insecticide-specific solid-phase extraction packing material prepared in Example 1 and add it to a 6 mL empty column. The organophosphorus insecticide-specific solid-phase extraction packing material prepared in Example 1 is located between two sintered polypropylene gaskets. Gently tap to make the packing material as uniform and compact as possible, and the organophosphorus insecticide-specific solid-phase extraction column is obtained.

[0062] Preparation of the comparative solid phase extraction column of Comparative Example 1: Weigh 500 mg of the comparative solid phase extraction packing material prepared in Comparative Example 1 and add it to a 6 mL empty column. The comparative solid phase extraction packing material prepared in Comparative Example 1 is located between two sintered polypropylene gaskets. Gently tap to make the packing material as uniform and compact as possible, and the comparative solid phase extraction column is obtained.

[0063] Conventional solid phase extraction column: 250 mg of graphitized carbon black packing and 200 mg of amine-based packing were added into a 6 mL empty column, and the packing was located between two pieces of sintered polypropylene gasket. The packing was lightly tapped to make it as uniform and compact as possible, and a conventional solid phase extraction column was prepared. The conventional solid phase extraction column can also use a commercially available solid phase extraction column with the same packing.

[0064] Preparation of mixed standard curve solution:

[0065] a) Accurately weigh 10.0 mg of dichlorvos standard after purity conversion, dissolve and dilute to 100.0 mL with acetone, mix uniformly to obtain a 100.0 mg / L dichlorvos standard stock solution, store at -20°C in the dark, and the storage period is 6 months;

[0066] b) Accurately weigh 10.0 mg of chlorpyrifos standard after purity conversion, dissolve and dilute to 100.0 mL with acetone, mix uniformly to obtain a 100.0 mg / L chlorpyrifos standard stock solution, store at -20°C in the dark, and the storage period is 6 months;

[0067] c) Accurately weigh 10.0 mg of malathion standard after purity conversion, dissolve and dilute to 100.0 mL with acetone, mix uniformly to obtain a 100.0 mg / L malathion standard stock solution, store at -20°C in the dark, and the storage period is 6 months;

[0068] d) Accurately measure 1.00 mL of dichlorvos standard stock solution, 1.00 mL of chlorpyrifos standard stock solution and 1.00 mL of malathion standard stock solution, and add them into a 100 mL volumetric flask, dilute with acetone, mix uniformly to obtain a 1.00 mg / L mixed standard solution, which is prepared for immediate use;

[0069] e) Accurately measure 2.00 mL of 1.00 mg / L mixed standard solution, dilute to 10.00 mL with acetone. Take 0 mL, 0.05 mL, 0.10 mL, 0.25 mL, 0.40 mL, 0.50 mL and 1.00 mL of the mixed standard solution, respectively, and add 1.00 mL, 0.95 mL, 0.90 mL, 0.75 mL, 0.60 mL, 0.50 mL and 0 mL of acetone, respectively, and mix uniformly to obtain mixed standard curve solutions with concentrations of 0 μg / L, 10 μg / L, 20 μg / L, 50 μg / L, 80 μg / L, 100 μg / L and 200 μg / L, respectively, which are prepared for immediate use.

[0070] Mixed standard sample preparation: 1 kg of spinach which was detected no residues of the organic phosphorus insecticide to be tested was cut into small pieces and then mashed into homogenate by a tissue crusher and placed in a polyethylene bottle. 10.00 g of spinach homogenate was weighed into 18 50 mL centrifuge tubes respectively, 1.00 mL of 0.50 mg / L mixed standard solution was added respectively, the centrifuge tubes were tightly screwed, vortexed for 10 minutes and then placed for 24 hours, and stored in the refrigerator to obtain 50 μg / L mixed standard spinach samples.

[0071] Blank sample preparation: 10.00 g of spinach homogenate was weighed into a 50 mL centrifuge tube respectively and stored in the refrigerator to obtain blank spinach samples.

[0072] The pretreatment process of the sample to be tested is described as follows:

[0073] a) Purification with the organic phosphorus insecticide special solid phase extraction column and the comparative solid phase extraction column: 25 mL of acetonitrile and 10 g of anhydrous sodium sulfate were added to the centrifuge tube of the mixed standard sample, oscillated on a shaker at a speed of 200 rpm for 30 minutes and then centrifuged at 4000 rpm for 5 minutes; 5 mL of supernatant was accurately taken, 5 mL of deionized water was added, mixed uniformly and then added to the organic phosphorus insecticide special solid phase extraction column and the comparative solid phase extraction column which had been activated with 50% acetonitrile water in advance, the drop rate of the solid phase extraction column was about 2 minutes / mL, then 10 mL of 50% acetonitrile water was used for elution, wherein the volume ratio of acetonitrile to water was 1:1; 10 mL of acetonitrile was used for elution; the eluate was evaporated to near dryness in a 50°C water bath by nitrogen blowing, 1.00 mL of acetone was accurately added, vortexed for 30 seconds, filtered with a 0.22 μm organic microporous filter to obtain the sample to be tested; one blank sample was selected, purified with one organic phosphorus insecticide special solid phase extraction column according to the above pretreatment process, and the serial number was named as sample 7; 12 standard samples were selected, 6 organic phosphorus insecticide special solid phase extraction columns and 6 comparative solid phase extraction columns were used as parallel, and the serial numbers were named as samples 8-13 and samples 14-19 respectively.

[0074] b) Purification with the conventional solid phase extraction column: 25 mL of acetonitrile and 10 g of anhydrous sodium sulfate were added to the centrifuge tube of the mixed standard sample, oscillated on a shaker at a speed of 200 rpm for 30 minutes and then centrifuged at 4000 rpm for 5 minutes; 5 mL of supernatant was accurately taken and added to the conventional solid phase extraction column which had been activated with acetonitrile in advance, the drop rate of the solid phase extraction column was about 2 minutes / mL; then 5 mL of acetonitrile was used for elution, the eluate was collected, evaporated to near dryness in a 50°C water bath by nitrogen blowing, 1.00 mL of acetone was accurately added, vortexed for 30 seconds, filtered with a 0.22 μm organic microporous filter to obtain the sample to be tested; 6 conventional solid phase extraction columns were selected as parallel, and the serial numbers were named as samples 20-25.

[0075] Gas chromatography-tandem mass spectrometer detection conditions:

[0076] a) Column: SH-Rxi-5ms column, quartz capillary, 30 m*0.25 mm*0.25 μm;

[0077] b) Temperature curve of column: initial temperature 50 ℃, keep 1 min, then increase to 125 ℃ at the rate of 25 ℃ / min, keep 10 min, then increase to 300 ℃ at the rate of 10 ℃ / min, keep 5 min;

[0078] c) Injection port temperature 250 ℃;

[0079] d) Interface temperature: 250 ℃;

[0080] e) Carrier gas: high purity He, flow rate 1.2 mL / min;

[0081] f) Injection volume: 1 μL;

[0082] g) Injection mode: splitless injection, valve open after 1.5 min;

[0083] h) Ionization mode: EI;

[0084] i) Ionization energy: 70 eV;

[0085] j) Measurement mode: selected ion monitoring mode;

[0086] k) Selected monitoring ions (m / z): see Table 1;

[0087] l) Solvent delay: 5 min;

[0088] m) Ion source temperature: 200 ℃;

[0089] n) Quadrupole temperature: 200 ℃.

[0090] Table 1 Retention time, quantitative and qualitative selected ions of dichlorvos, malathion and chlorpyrifos

[0091]

[0092] Figure 2The chromatogram and recovery concentration data of dichlorvos, malathion and chlorpyrifos in sample 8 are shown in Table 2. The average recovery rate and method precision of dichlorvos, chlorpyrifos and malathion in spinach samples are shown in Table 2. As can be seen from Table 2, the recovery rate using the organic phosphorus insecticide special solid phase extraction column is between 70% and 110%, and the recovery rate and precision meet the requirements of residue detection; the recovery rate of the comparative solid phase extraction column is low and unstable, and the precision is poor because there is no specific pore for retaining the target organic phosphorus insecticide molecules; the recovery rate of the conventional solid phase extraction column is between 70% and 110%, and the recovery rate and precision meet the requirements of residue detection, but the recovery rate of chlorpyrifos and malathion is generally higher than 100%, indicating that the impurities are not removed enough, the matrix effect is obvious, and the precision is slightly worse than that of the organic phosphorus insecticide special solid phase extraction column; since the purification of the organic phosphorus insecticide special solid phase extraction column is based on the mechanism of retaining target substances by solid phase extraction columns, impurities can be completely removed in the process of elution, so that the sample injection liquid after purification is colorless and transparent; while the conventional solid phase extraction column is based on the mechanism of retaining impurities by solid phase extraction columns, since the impurities are large in amount and cannot be completely removed, and are easily eluted by the elution liquid, the sample injection liquid after purification is light green, as shown in Figure 3 which will greatly increase the maintenance frequency of gas chromatography-tandem mass spectrometry, affect the detection results, and even shorten the service life of the equipment.

[0093] Table 2. Average recovery rate and precision of dichlorvos, chlorpyrifos and malathion in spinach samples

[0094]

[0095] In summary, the organic phosphorus special solid phase extraction column has good specificity for organic phosphorus insecticides, high detection sensitivity, complete impurity removal, small influence on detection equipment, good filler stability, high strength, strong chemical resistance, no inclusion of substances to be detected, and no influence on residue detection.

[0096] The above description is only an embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent transformation or direct or indirect application in related technical fields based on the content of the present application is also included in the patent protection scope of the present application.

Claims

1. A method for preparing a solid phase extraction packing material specific for organophosphorus insecticides, characterized by, The method comprises the following steps: S1, in weight parts, 16.7-24.7 parts of substituted hydroxy aniline is added into a reaction kettle, 14.1-15.5 parts of alkenyl isocyanate is slowly added dropwise within 1-2 hours, stirred uniformly, 0.04-0.06 parts of a catalyst for synthesizing polyurethane is added at 45-55℃, reacted for 2-4 hours; 27.8 parts of 3-(2,3-epoxypropoxy) propyl triethoxysilane is continuously added, stirred for 0.5 hours, 0.1-0.2 parts of a catalyst for synthesizing epoxy compound is added, heated to 50-60℃, reacted for 2-3 hours; cooled to 20-30℃, 30-35 parts of saturated sodium bicarbonate aqueous solution is added, the epoxy catalyst is removed by shaking, the organic phase is washed with 300 parts of deionized water for 3 times, and the water phase is discarded; the organic phase is dried with 4A molecular sieve, and a reactive template molecule composition is obtained; S2, in weight parts, 100 parts of styrene, 4-9 parts of a crosslinking agent and 0.5-1.2 parts of an initiator are uniformly mixed and dissolved to obtain oil phase A; 6-9 parts of the reactive template molecule composition, 10-15 parts of styrene, 10-15 parts of a crosslinking agent and 10-15 parts of vinyl acetate are uniformly mixed and dissolved, 30-40 parts of 0.25% sodium dodecyl sulfate aqueous solution is added, stirred at 800-1000 rpm for 0.5-1 hour to obtain oil phase B; 4-6 parts of polyvinyl alcohol 1788 and 10-15 parts of sodium chloride are dissolved in 400-500 parts of deionized water, oil phase A is added, stirred at 1200-1500 rpm and heated to 60-70℃, and after being kept for 2-3 hours, oil phase B is added dropwise into the reaction kettle within 2-4 hours; after the dropwise addition is completed, the temperature is kept for 3-5 hours, and then cooled to 20-30℃; the microspheres are washed with 300 parts of deionized water for 3 times, dried at 60℃, and sieved, 400-1000 mesh microspheres are taken, and crosslinked polymer microspheres are obtained; S3, in weight parts, 10 parts of the polymer microspheres are added into 160-180 parts of 24% sodium hydroxide solution, heated to 90-100℃, reacted for 3-5 hours, then cooled to 20-30℃, washed with deionized water until neutral, extracted with 400 parts of a mixed solvent of ethanol, toluene and acetic acid under boiling conditions for 10-12 hours, and the microspheres are washed with 200 parts of ethanol, and vacuum dried at 60℃ to obtain a solid-phase extraction filler special for organophosphorus insecticides.

2. The method of claim 1, wherein the method is characterized by: The substituted hydroxy aniline in step S1 is a combination of at least two of 3'-(3-hydroxyphenyl) aniline, 4'-(4-hydroxyphenyl) aniline, 5-bromo-4-fluoro-2-hydroxy aniline, 2-chloro-4-methyl-3-hydroxy aniline, 2-nitro-4-hydroxy aniline, 4-amino-2,6-dichloro-5-fluoro phenol, 4-amino-2,6-dichlorophenol and 4-amino-2,6-dibromo phenol.

3. The method of claim 1, wherein the method is characterized by: The alkenyl isocyanate in step S1 is one of 2-isocyanatoethyl acrylate or 2-isocyanatoethyl methacrylate.

4. The method of claim 1, wherein the method is characterized by, The polyurethane catalyst in step S1 is an organic bismuth catalyst.

5. The method of claim 1, wherein the method is characterized by: The epoxy catalyst in step S1 is boron trifluoride etherate.

6. The method of claim 1, wherein the method is characterized by: The cross-linking agent in step S2 is a combination of one or more of divinyl benzene, N-methyl diallylamine, and ethylene glycol diallyl ether, with a concentration of 80%.

7. The method of claim 1, wherein the method is characterized by: The initiator in step S2 is one of dodecanoyl peroxide or azobisisobutyronitrile.

8. The method of claim 1, wherein the solid phase extraction sorbent is specific for organophosphorus insecticides. The volume ratio of the mixed solvent of ethanol, toluene, and acetic acid in step S3 is 2:8:

1.

9. The solid phase extraction filler for organic phosphorus insecticide prepared by the method according to any one of claims 1-8.

10. The solid phase extraction filler for organic phosphorus insecticide according to claim 9 is applied to the detection of organic phosphorus insecticide residues in food and agricultural products.

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