Eutectic solvent as well as preparation method and application thereof

Abstract

The invention discloses a eutectic solvent and a preparation method and application thereof, the eutectic solvent comprises a hydrogen bond donor compound and a hydrogen bond acceptor compound, the hydrogen bond donor compound is one of fatty acids, and the hydrogen bond acceptor compound is indoxacarb; the fatty acid is at least one of oleic acid, linoleic acid and linolenic acid; the molar ratio of the hydrogen bond acceptor compound to the hydrogen bond donor compound is 1: 1-1: 3. The eutecticevaporate solvent has good activity on solenopsis invicta, is insoluble in water, is dispersed in water by using an emulsifier, is prepared into CaCO3 drug-loaded nanoparticles by using an interface precipitation method, has a certain slow release characteristic, has a good control effect on the solenopsis invicta, has a comprehensive control effect improved by about 12% compared with a commercial medicament, inhibits a nest migrant behavior of the solenopsis invicta, and can be used for preventing and treating the solenopsis invicta. And after 28 days, a good control effect on live ant nests is still achieved, and the control effect reaches 61% and is improved by 32% compared with that of a commercial preparation.

Description

Technical Field

[0001] The present invention relates to the technical field of red imported fire ant control, and in particular to a low eutectic solvent and a preparation method and application thereof. Background Art

[0002] The red fire ant (Solenopsis invicta Buren) is one of the 100 most threatening alien invasive species in the world. The red fire ant has strong adaptability, lacks natural enemies in my country, has a wide potential distribution area, and seriously harms agricultural production and human and animal health. It is of great significance to carry out red fire ant prevention and control.

[0003] At present, the main means of controlling red fire ants is still chemical pesticides, mainly baits. Indoxacarb is a recommended pesticide in my country's "Technical Regulations for Chemical Control of Red Fire Ants". The application of indoxacarb bait has a significant effect on the control of red fire ants in the short term, but in actual use, it is found that the long-term effect is poor, the control is not thorough, and it is easy to cause red fire ants to move their nests. Many regions have reported that after one year of control, red fire ants will become rampant again in the affected areas.

[0004] Nano drug-loaded particles have the advantages of slowing down the release rate of pesticides, extending the effective period, reducing the amount of release in non-target areas and environments, and reducing residual pollution. They are currently a hot topic in the field of nanotechnology application research in agriculture, but there are relatively few reports on nano preparations for the prevention and control of red fire ants.

[0005] Deep Eutectic Solvent (DES) is a low melting point eutectic mixture formed by hydrogen bond interactions of hydrogen bond acceptors (HBA) and hydrogen bond donors (HBD) at a certain molar ratio. It has the advantages of simple preparation, stable composition, low volatility, safety and non-toxicity, and convenient storage. However, there is no report on the preparation of indoxacarb as a eutectic solvent. Summary of the invention

[0006] In view of the above-mentioned technical problems in the related art, the present invention proposes a low eutectic solvent and a preparation method and application thereof; by coating the low eutectic solvent, it has certain sustained-release characteristics, prolongs its effective period, and improves the control effect on red fire ants; thereby overcoming the shortcomings of the prior art.

[0007] To achieve the above technical objectives, the technical solution of the present invention is implemented as follows:

[0008] In a first aspect, the present invention provides a deep eutectic solvent;

[0009] The low eutectic solvent comprises a hydrogen bond donor compound and a hydrogen bond acceptor compound, wherein the hydrogen bond donor compound is one of fatty acids, and the hydrogen bond acceptor compound is indoxacarb.

[0010] Furthermore, the fatty acid is at least one of oleic acid, linoleic acid and linolenic acid.

[0011] Furthermore, in the low eutectic solvent, the molar ratio of the hydrogen bond acceptor compound to the hydrogen bond donor compound is 1:1 to 1:3.

[0012] In a second aspect, the present invention provides a method for preparing the above-mentioned low eutectic solvent, which adopts the following technical scheme: a hydrogen bond donor and a hydrogen bond acceptor are mixed, and heated under a vacuum state at 80 to 100° C. for 2 hours until the mixture becomes clear and transparent, thereby obtaining the low eutectic solvent.

[0013] In a third aspect, the present invention provides a method for preparing CaCO3 drug-loaded nanoparticles based on the above-mentioned deep eutectic solvent, using the following technical scheme;

[0014] The preparation method of the CaCO3 drug-loaded nanoparticles comprises the following steps:

[0015] S1. The low eutectic solvent and the emulsifier FMES were thoroughly mixed in a weight ratio of 1:10, dispersed in a CaCl2 solution, and Na2CO3 solution was slowly added dropwise at 1000rpm and stirred for 1 hour;

[0016] S2. The solution in step S1 was allowed to stand for 12 hours, centrifuged at 10,000 rpm for 12 minutes, washed with distilled water three times, and dried under vacuum at 70°C overnight.

[0017] In a fourth aspect, the present invention provides a red fire ant bait based on the above-mentioned CaCO3 drug-loaded nanoparticles, which includes the following raw materials in mass percentage: CaCO3 drug-loaded nanoparticles containing 0.05% indoxacarb, 0.5% nano-adjuvant, 10% white sugar, 10% attractant, 10% peanut oil, and corn flour supplemented to 100%.

[0018] In a fifth aspect, the present invention provides an application of the above-mentioned red fire ant bait in the control of red fire ants.

[0019] The specific beneficial effects of the present invention are as follows:

[0020] Firstly, the preparation method of the low eutectic solvent provided by the present invention is simple and easy to operate, has low requirements on equipment, has stable ingredients, is not easy to volatilize, does not generate toxic and harmful substances, and is green and environmentally friendly;

[0021] Secondly, the CaCO3 drug-loaded nanoparticles provided by the present invention have a sustained release property, which causes little harm to the surrounding environment and animals and plants during the application of the drug, and meets the characteristics of green pesticides;

[0022] Thirdly, the red fire ant bait provided by the present invention has a good control effect on red fire ants, and has the advantages of fast effect, strong lasting effect and thorough control. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 This is a comparison diagram before and after the preparation of a deep eutectic solvent according to an embodiment of the present invention;

[0025] Figure 2 It is a particle size distribution diagram and a scanning electron microscope image of CaCO3 drug-loaded nanoparticles based on the eutectic solvent according to an embodiment of the present invention; DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0027] Unless otherwise specified, all technical terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0028] The instruments, equipment and reagents used in the examples were obtained from commercial sources.

[0029] Embodiment 1:

[0030] A red fire ant bait based on the above-mentioned CaCO3 drug-loaded nanoparticles is prepared as follows:

[0031] S1. Accurately weigh 5.50 g of indoxacarb and 8.47 g of oleic acid, stir and mix, then place the mixture in a vacuum drying oven, and heat it at 100° C. under vacuum for 2 hours until the solution becomes clear and transparent, thereby obtaining a low eutectic solvent.

[0032] S2. Take 100 μL of a low eutectic solvent prepared in step S1, add 1 mL of FMES thereto and stir to mix, then dissolve in 50 mL of 0.04 M calcium chloride solution (containing 10% ethylene glycol), then drop 50 mL of 0.04 M sodium carbonate solution (containing 10% ethylene glycol) under stirring at 1000 rpm. After the addition is complete, continue stirring for 1 hour. After standing for 12 hours, centrifuge at 10000 rpm for 12 minutes, wash the precipitate with distilled water 3 times, and completely dry it in a vacuum drying oven at 70°C to obtain CaCO3 drug-loaded nanoparticles based on the above-mentioned low eutectic solvent.

[0033] S3. Weigh 3.10 g of the CaCO3 drug-loaded nanoparticles based on the above-mentioned low eutectic solvent prepared in step S2, add 1 g of diatomaceous earth, 20 g of white sugar, 20 g of a mixture of chicken meal and fish meal (mass ratio of 1:1), 20 g of peanut oil, and 136.90 g of corn flour, stir evenly, grind with a mortar, and pass through a 14-mesh sieve to obtain indoxacarb nano red fire ant bait, which is stored for later use.

[0034] Result analysis:

[0035] 1. Determine the drug loading of the coated indoxacarb nanomaterial obtained in step S2 by the following method:

[0036] 5, 10, 15, 20, and 25 μg / mL indoxacarb-ethanol solutions were prepared, and the absorbance of the solutions was measured using a UV spectrophotometer. An indoxacarb standard curve was plotted with concentration as the abscissa and absorbance as the ordinate, and the linear equation of the standard curve was calculated to be y=0.0271x+0.1128.

[0037] Weigh 8 mg of the CaCO3 drug-loaded nanoparticles obtained in step S2, disperse them with 8 mL of anhydrous ethanol, and ultrasonicate them at 500 W for 20 minutes to release the indoxacarb encapsulated therein. Centrifuge at 10,000 rpm for 12 minutes, take the supernatant, test its absorbance using a UV spectrophotometer, calculate the indoxacarb content in the CaCO3 drug-loaded nanoparticles obtained in step S2 using the indoxacarb standard curve, and calculate the drug loading of the nanomaterial according to the following formula:

[0038] Drug loading (%) = indoxacarb content in the material / total weight of drug-loaded particles added × 100.

[0039] The test results showed that after being coated with calcium carbonate, the drug loading of indoxacarb was 3.22%.

[0040] 2. The apparent morphology, hydrated particle size, zeta potential and polydispersity index (PDI) of the coated indoxacarb nanomaterial prepared in step S2 were investigated as follows:

[0041] Weigh 10 mg of the coated indoxacarb nanomaterial prepared in step S2, add 10 mL of anhydrous ethanol, and ultrasonically disperse for 30 minutes. Draw 10 μL of the dispersed liquid droplets on the surface of the single crystal silicon wafer and air dry naturally. After gold spraying, observe using a field emission scanning electron microscope S-4800 (SEM). The results are shown in Figure 2 The diameters of 200 nanoparticles were randomly selected and measured using Image J (V13.0.6.). The particle size frequency distribution histogram was drawn using Origin 2022, and the average particle size was calculated. Figure 2 Part A of

[0042] Weigh 10 mg of material, add 10 mL of anhydrous ethanol, and ultrasonically disperse for 30 minutes. Use a nanoparticle size and zeta potential instrument to determine the hydrated particle size, surface zeta potential and polydispersity index (PDI) of the material in aqueous solution. Each treatment is measured three times.

[0043] Depend on Figure 2 As can be seen from Part B and Part C, the CaCO3 drug-loaded nanoparticles prepared in step S2 are substantially round, uniform in size, and have a rough surface. Single-shell microcapsules are formed by the deposition of calcium carbonate on the surface of the eutectic solvent droplets. Figure 2 From the statistical results of part A, it can be seen that the average particle size of CaCO3 coated oleic acid eutectic solvent is 0.591±0.10μm. The hydrated particle size of the nanomaterial is 753.60±18.81nm, the zeta potential is 29.52±1.16mV, and the PDI is 0.30±0.01 as measured by the nanoparticle size and zeta potential instrument.

[0044] Effect example:

[0045] The control effect of the red fire ant bait prepared in the example on red fire ants was investigated as follows:

[0046] The experiment was conducted in the fourth-level occurrence area of ​​red fire ants, with an area of ​​300m 2 The area of ​​about 1000 square meters contains at least 5 live ant nests. One day before spraying, the worker ants in the ant nests were trapped by trapping and the base number was counted. The trapping method refers to the "GB / T 23626-2009 Red Fire Ant Epidemic Monitoring Procedure", and the specific method is as follows:

[0047] Place the ham bait in a 50mL centrifuge tube and mark it for treatment to make a monitoring bottle. At around 9:00 am, insert the experimental treatment sign next to the determined test ant nest, and place the monitoring bottle 50cm away from the ant nest in the four directions of east, south, west and north. Set up three replicates for each treatment. After 30 minutes, cover, seal and retract the monitoring bottle, add 5mL of 75% ethanol, and record the number of traps in each bottle after the red fire ants die. If other types of ants are trapped, they should be properly preserved and identified. In subsequent investigations and traps, the monitoring bottles are placed at the locations of the first investigation.

[0048] Take 20g of the bait prepared in Example 1 and spread it around the ant nest, take the commercial agent (0.05% indoxacarb ant killing bait) as the agent control group, take the diatomaceous earth + CaCO3 bait as the material control group, take the ant nest without any treatment as the blank control, and repeat each treatment 3 times. On the 7th, 14th, 21st and 28th day after spreading the agent, the worker ants were attracted by the ham sausage trapping method, and the control effect on the worker ants and the live ant nest was calculated; and after the last trapping, the ant nest was excavated, the ant colony level was counted, and the control effect on the ant colony and the comprehensive control effect were calculated. The calculation method refers to "GBT 17980.149-2009 Pesticide Field Efficacy Test Guidelines (II) Part 149: Pesticide Control of Red Fire Ants".

[0049] Prevention results:

[0050] 1. The results of the control of worker ants are shown in Table 1. After 7 days of application, the control effect of the commercial agent can reach 100%; the nanomaterial control mixed with diatomaceous earth and calcium carbonate has almost no control effect on worker ants, only 3.58%; the control effect of the nano-composite preparation compound treatment group (diatomaceous earth and CaCO3 drug-loaded nanoparticles) on worker ants reached 99.71%, which has a good control effect on worker ants. With the extension of the application time, the control effect of the commercial agent on worker ants gradually decreased, from 100% on the 7th day to 92.33% on the 28th day; the control effect of the nanomaterial control group on worker ants increased, from 3.58% to 14.16%; the control effect of the nano-composite preparation treatment group on worker ants was always maintained at more than 99.64%, and a good control effect was maintained.

[0051] Table 1 Control effect of nano compound preparations on worker ants

[0052]

[0053] As shown in Table 2, in terms of the control effect on live ant nests, after 7 and 14 days of application, the commercial agent control group and the nano-composite preparation treatment group had good control effects on live ant nests, with control effects above 92.86%. However, after 21 and 28 days of application, the control effect of the commercial agent on live ant nests decreased significantly, with the control effect dropping to 46.11% on 21 days and only 28.70% on 28 days; the control effect of the nano-composite preparation treatment group on live ant nests also decreased, with the control effect dropping to 76.91% on 21 days and 61.11% on 28 days. On the 28th day, the control effect of the compound treatment group on live ant nests was significantly higher than that of the commercial agent control group. The control effect of the nanomaterial control group on live ant nests was always below 10%, with almost no control effect.

[0054] Table 2 The control effect of nano compound preparation on live ant nests

[0055]

[0056] As shown in Table 3, after 28 days of treatment, the commercial pesticide treatment group caused the migration of ant nests, and the number of new ant nests increased, accounting for 32.87% of the total ant nests in the community, while the nano-composite preparation treatment group was only 16.67%, about half of the commercial preparation treatment group. The blank control and nanomaterial control group was 11.11%.

[0057] Table 3 The proportion of newly added ant nests to the total number of ant nests in the plot after 28 days of treatment

[0058]

[0059] As shown in Table 4, in the control effect on ant colonies, 28 days after the application of the pesticide, the treated ant nests were dug up and the remaining red fire ants in the ant nests were observed. The commercial agent control group and the nano-composite preparation treatment group both had good control effects on ant colonies, with control efficiencies of 85.19% and 92.59% respectively, with no significant difference between the two; the nano-material control group had no control effect on ant colonies.

[0060] Table 4 The control effect of nano compound preparation on ant colonies

[0061]

[0062] As shown in Table 5, 28 days after application, the comprehensive control effect of the nanomaterial control group on red fire ants was only 4.83%, which had almost no control effect on red fire ants; the comprehensive control effect of the commercial agent control group was 68.84%; the nano-compound preparation treatment group had the best comprehensive control effect on red fire ants, reaching 80.39%, which was 11.55% higher than that of the commercial agent.

[0063] Table 5 Comprehensive control effect of nano compound preparations on red fire ants

[0064]

[0065] In summary, with the help of the above technical solution of the present invention, the following beneficial effects can be achieved:

[0066] The preparation method of low eutectic solvent is simple and easy to operate, with low equipment requirements, stable ingredients, non-volatile, no toxic and harmful substances generated, and green and environmentally friendly. CaCO3 drug-loaded nanoparticles have slow-release properties, little harm to the surrounding environment and animals and plants, and meet the characteristics of green pesticides; red fire ant bait has a good control effect on red fire ants, and has the advantages of fast effect, strong lasting effect, thorough control, and low application amount.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A deep eutectic solvent, characterized in that: The low eutectic solvent comprises a hydrogen bond donor compound and a hydrogen bond acceptor compound, wherein the hydrogen bond donor compound is one of fatty acids, and the hydrogen bond acceptor compound is indoxacarb.

2. A deep eutectic solvent according to claim 1, characterized in that The fatty acid is at least one of oleic acid, linoleic acid and linolenic acid.

3. A deep eutectic solvent according to claim 1, characterized in that In the low eutectic solvent, the molar ratio of the hydrogen bond acceptor compound to the hydrogen bond donor compound is 1:1 to 1:

3.

4. A method for preparing the deep eutectic solvent according to any one of claims 1 to 3, characterized in that: The low eutectic solvent is obtained by mixing a hydrogen bond donor and a hydrogen bond acceptor, heating them under vacuum at 80-100° C. for 2 hours until they become clear and transparent.

5. A method for preparing CaCO3 drug-loaded nanoparticles based on the deep eutectic solvent according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. The deep eutectic solvent and the emulsifier FMES were thoroughly mixed in a weight ratio of 1:10, dispersed in a CaCl2 solution, and Na2CO3 solution was slowly added dropwise at 1000rpm and stirred for 1 hour; S2. The solution in step S1 was allowed to stand for 12 hours, centrifuged at 10,000 rpm for 12 minutes, washed with distilled water three times, and dried under vacuum at 70° C. overnight.

6. A red fire ant bait based on the CaCO3 drug-loaded nanoparticles according to claim 5, characterized in that: Counted by mass percentage, the raw materials include the following mass percentages: CaCO3 drug-loaded nanoparticles containing 0.05% indoxacarb, 0.5% nano-adjuvant, 10% white sugar, 10% attractant, 10% peanut oil, and corn flour is supplemented to 100%.

7. A red fire ant poison bait according to claim 6, characterized in that: The nano auxiliary agent is diatomaceous earth.

8. The red fire ant poison bait according to claim 7, characterized in that: The attractant is a mixture of chicken meal and fish meal; in terms of weight, the ratio of the chicken meal to the fish meal is 1:

1.

9. Use of the red fire ant bait as claimed in claim 8 in the control of red fire ants.

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