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1.
ACS Appl Mater Interfaces ; 13(33): 39066-39075, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34387079

RESUMO

A controlled release formulation based on silica microcapsules is an ideal selection to improve both the effective utilization and duration of pesticides to decrease ecological damage. Herein, a simple and green method for preparing double-shelled microcapsules was developed using a newly prepared quaternary ammonium ionic liquid (IL) as the functional additive to entrap avermectin (Ave) in mesoporous silica nanospheres (MSNs) and tannic acid-Cu (TA-Cu) complex as the sealing agent to form the core-shell structure (Ave-IL@MSN@TA-Cu). The obtained microcapsules with an average size of 538 nm had pH-responsive release property and good stability in soil. The half-life of microcapsules (34.66 days) was 3 times that of Ave emulsifiable concentrate (EC) (11.55 days) in a test soil, which illustrated that microcapsules could protect Ave from rapid degradation by microorganisms by releasing TA, copper, and quaternary ammonium in the soil. Ave-IL@MSN@TA-Cu microcapsules had better nematicidal activity and antibacterial activity than Ave EC due to the synergistic effect of Ave, IL, and copper incorporated in the microcapsules. Pot experiments showed that the control efficacy of microcapsules was 87.10% against Meloidogyne incognita, which is better than that of Ave EC (41.94%) at the concentration of 1.0 mg/plant by the root-irrigation method after 60 days of treatment owing to the extended duration of Ave in microcapsules. The simple and green method for the preparation of double-shelled microcapsules based on natural quaternary ammonium IL would have tremendous potential for the extensive development of controlled release pesticide formulations.


Assuntos
Cápsulas/química , Preparações de Ação Retardada/química , Controle de Pragas/métodos , Praguicidas/química , Dióxido de Silício/química , Tylenchoidea/efeitos dos fármacos , Animais , Complexos de Coordenação/química , Cobre/química , Preparações de Ação Retardada/farmacologia , Composição de Medicamentos , Liberação Controlada de Fármacos , Química Verde , Concentração de Íons de Hidrogênio , Líquidos Iônicos/química , Ivermectina/análogos & derivados , Ivermectina/química , Ivermectina/farmacologia , Praguicidas/farmacologia , Porosidade , Compostos de Amônio Quaternário/química , Solubilidade , Taninos/química , Fatores de Tempo
2.
J Agric Food Chem ; 69(23): 6485-6494, 2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34077226

RESUMO

Silver nanoparticles (AgNPs) have remarkable and broad-spectrum antibacterial activities against Gram-positive (G+) and Gram-negative bacteria (G-). However, the negative surface potential of AgNPs limits their antibacterial activities due to the electrostatic repulsion with the negatively charged bacterial cell membrane. To address the limitation, AgNPs were loaded in the mesoporous silica nanoparticles by preparing silver core-mesoporous silica shell nanocapsules (Ag@MSNs), and then, a cationic antibacterial polymer, quaternary ammonium polyethyleneimine (QPEI), was used to modify Ag@MSNs for improving their surface potential and antibacterial activities. The results showed that the obtained Ag@MSN-QPEI exhibited a high positive surface potential (+39.6 mV) and a strong electrostatic attraction with Pseudomonas syringae pv. lachrymans cells in coculture, resulting in an excellent bacterial cell-targeting effect. At the same concentration, Ag@MSN-QPEI exhibited less silver content (reducing the silver content of Ag@MSNs by 19%), higher antibacterial activities, and longer effective duration against Clavibacter michiganensis subsp. michiganensis (G+) and P. syringae pv. lachrymans (G-) than Ag@MSNs and QPEI alone. The excellent bacterial cell-targeting effect and synergistic antibacterial action combined with QPEI accounted for the significantly enhanced antibacterial activities of Ag@MSN-QPEI. Therefore, using a cationic antibacterial polymer to confer the bacterial cell-targeting effect and synergistic antibacterial action would be extended to other antimicrobial materials.


Assuntos
Compostos de Amônio , Nanopartículas Metálicas , Nanocápsulas , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana , Polietilenoimina , Dióxido de Silício , Prata/farmacologia
3.
Sci Total Environ ; 787: 147422, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-33991920

RESUMO

In this work, a pH-responsive pesticide delivery system using mesoporous silica nanoparticles (MSNs) as the porous carriers and coordination complexes of Cu ions and tannic acid (TA-Cu) as the capping agent was established for controlling pyraclostrobin (PYR) release. The results showed the loading capacity of PYR@MSNs-TA-Cu nanoparticles for pyraclostrobin was 15.7 ± 0.5% and the TA-Cu complexes deposited on the MSNs surface could protect pyraclostrobin against photodegradation effectively. The nanoparticles had excellent pH responsive release performance due to the decomposition of TA-Cu complexes under the acid condition, which showed 8.53 ± 0.37%, 82.38 ± 1.67% of the encapsulated pyraclostrobin were released at pH 7.4, pH 4.5 after 7 d respectively. The contact angle and adhesion work of PYR@MSNs-TA-Cu nanoparticles on rice foliage were 86.3° ± 2.7° and 75.8 ± 3.1 mJ/m2 after 360 s respectively, indicating that TA on the surface of the nanoparticles could improve deposition efficiency and adhesion ability on crop foliage. The control effect of PYR@MSNs-TA-Cu nanoparticles against Rhizoctonia solani with 400 mg/L of pyraclostrobin was 85.82% after 7 d, while that of the same concentration of pyraclostrobin EC was 53.05%. The PYR@MSNs-TA-Cu nanoparticles did not show any phytotoxicity to the growth of rice plants. Meanwhile, the acute toxicity of PYR@MSNs-TA-Cu nanoparticles to zebrafish was decreased more than 9-fold compared with that of pyraclostrobin EC. Thus, pH-responsive PYR@MSNs-TA-Cu nanoparticles have great potential for enhancing targeting and environmental safety of the active ingredient.


Assuntos
Nanopartículas , Peixe-Zebra , Animais , Meio Ambiente , Concentração de Íons de Hidrogênio , Porosidade , Rhizoctonia , Dióxido de Silício , Estrobilurinas
4.
J Agric Food Chem ; 69(8): 2382-2391, 2021 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-33605718

RESUMO

Considering the severity of plant pathogen resistance toward commonly used agricultural microbicides, as well as the potential threats of agrichemicals to the eco-environment, there is a pressing need for antimicrobial approaches that are capable of inactivating pathogens efficiently without the risk of inducing resistances and harm. In this work, a porphyrin metal-organic framework (MOF) nanocomposite was constructed by incorporating 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin tetra(p-toluenesulfonate) (TMPyP) as a photosensitizer (PS) in the cage of a variant MOF (HKUST-1) to efficiently produce singlet oxygen (1O2) to inactivate plant pathogens under light irradiation. The results showed that the prepared PS@MOF had a loading rate of PS about 12% (w/w) and excellent and broad-spectrum photodynamic antimicrobial activity in vitro against three plant pathogenic fungi and two pathogenic bacteria. Moreover, PS@MOF showed outstanding control efficacy against Sclerotinia sclerotiorum on cucumber in the pot experiment. Allium cepa chromosome aberration assays and safety evaluation on cucumber and Chinese cabbage indicated that PS@MOF had no genotoxicity and was safe to plants. Thus, porphyrin MOF demonstrated a great potential as an alternative and efficient new microbicide for sustainable plant disease management.


Assuntos
Anti-Infecciosos , Estruturas Metalorgânicas , Porfirinas , Anti-Infecciosos/farmacologia , Ascomicetos , Gerenciamento Clínico , Fármacos Fotossensibilizantes/farmacologia , Porfirinas/farmacologia
5.
Front Microbiol ; 11: 870, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32477298

RESUMO

Allyl isothiocyanate (AITC) is a natural product used as a food additive. Due to its strong volatility and broad biological activity, AITC is considered as a bio-fumigant to control soil-borne fungal diseases in agriculture, creating an urgent need for evaluation of the antifungal activity of AITC. Here we study the effect of AITC on Fusarium solani growth and explore the molecular mechanisms. The results indicated that AITC causes rapid inhibition of F. solani after 5 min, hyphal deformity, and electrolyte leakage. A yeast-like vacuolar transient receptor potential channel regulator (FsYvc1, a STRPC family member) was identified in F. solani that seems to play a role in this fungi AITC sensitivity. Genetic evidence suggests the gene FsYvc1 is involved in F. solani growth, development, and pathogenicity. Loss of FsYvc1 resulted in hypersensitivity of F. solani to AITC and induced reactive oxygen species (ROS) accumulation ∼ 1.3 to 1.45- folds that of the wild type (WT), and no difference responses to CaCl2, NaCl, KCl, SDS, and Congo red when compared with WT. In addition, ΔFsYvc1-17 showed significantly reduced (∼ 1-fold) glutathione-S-transferase (GST) expression compared with the WT without AITC induction. Upon exposure to 4.8 µg/mL AITC for 3 h, the relative expression levels were ∼ 12-30 fold higher in both the WT and ΔFsYvc1-17. Nevertheless, no difference in GST expression level was observed between the WT and ΔFsYvc1-17. The current study provides novel insights into the toxicity mechanisms of AITC. Considering our results that show the key role of FsYvc1, we propose that it could act as a new molecular target for future fungicide development.

6.
J Agric Food Chem ; 68(22): 6048-6057, 2020 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-32392059

RESUMO

In this work, 12 novel herbicidal ionic liquids (HILs) based on acifluorfen were prepared by pairing with the fluorescent hydrazides or different alkyl chains for increasing activities and reducing negative impacts on the aquatic environment. The results showed that the fluorescence of coumarin hydrazide in the HILs was applied as the internal and supplementary light source to meet the requirement of light wavelength range of acifluorfen, which improved the phytotoxicity of acifluorfen to weeds by enhancing singlet oxygen generation with increased sunlight utilization. The herbicidal activities of HILs were related positively with the length of chain of cation under high light intensity and depended mainly on the fluorescence characteristic of the cation under low light intensity, and the double salt IL forms of acifluorfen containing coumarin hydrazide and n-hexadecyltrimethylammonium had enhanced efficacies against broadleaf weeds in the field. Compared with acifluorfen sodium, HILs had lower water solubility, better surface activity, weaker mobility in soils, and higher decomposition temperature. These results demonstrated that HILs containing different cations provided a wider scope for fine-tuning of the physicochemical and biological properties of herbicides and established a promising way for the development of environmentally friendly herbicidal formulations.


Assuntos
Herbicidas/química , Herbicidas/farmacologia , Líquidos Iônicos/química , Nitrobenzoatos/química , Nitrobenzoatos/farmacologia , Composição de Medicamentos , Fluorescência , Líquidos Iônicos/farmacologia , Plantas Daninhas/efeitos dos fármacos , Plantas Daninhas/metabolismo , Plantas Daninhas/efeitos da radiação , Oxigênio Singlete/metabolismo , Solubilidade/efeitos da radiação , Luz Solar
7.
J Hazard Mater ; 389: 122075, 2020 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-31972522

RESUMO

It is highly desirable to construct stimuli-responsive nanocarriers for improving pesticides targeting and preventing the pesticides premature release. In this work, a novel redox and α-amylase dual stimuli-responsive pesticide delivery system was established by bonding functionalized starch with biodegradable disulfide-bond-bridged mesoporous silica nanoparticles which loaded with avermectin (avermectin@MSNs-ss-starch nanoparticles). The results demonstrated that the loading capacity of avermectin@MSNs-ss-starch nanoparticles for avermectin was approximately 9.3 %. The starch attached covalently on the mesoporous silica nanoparticles could protect avermectin from photodegradation and prevent premature release of active ingredient. Meanwhile, the coated starch and disulfide-bridged structure of nanoparticles could be decomposed and consequently release of the avermectin on demand when nanoparticles were metabolized by glutathione and α-amylase in insects. The bioactivity survey confirmed that avermectin@MSNs-ss-starch nanoparticles had a longer duration in controlling Plutella xylostella larvae compared to avermectin emulsifiable concentrate. In consideration of the superior insecticidal activity and free of toxic organic solvent, this target-specific pesticide release system has promising potential in pest management.


Assuntos
Portadores de Fármacos/química , Inseticidas/toxicidade , Ivermectina/análogos & derivados , Nanopartículas/química , Dióxido de Silício/química , Amido/química , Animais , Portadores de Fármacos/síntese química , Portadores de Fármacos/metabolismo , Portadores de Fármacos/efeitos da radiação , Liberação Controlada de Fármacos , Estabilidade de Medicamentos , Glutationa/metabolismo , Concentração de Íons de Hidrogênio , Inseticidas/efeitos da radiação , Ivermectina/efeitos da radiação , Ivermectina/toxicidade , Cinética , Luz , Mariposas/efeitos dos fármacos , Mariposas/enzimologia , Nanopartículas/efeitos da radiação , Oxirredução , Controle de Pragas/métodos , Porosidade , Dióxido de Silício/efeitos da radiação , Amido/metabolismo , Amido/efeitos da radiação , alfa-Amilases/metabolismo
8.
J Agric Food Chem ; 67(40): 11018-11024, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31512873

RESUMO

In this study, nine pyrimethanil ionic liquids (PILs) were synthesized through an acid-base reaction with nine naturally derived organic acid anions to improve the physicochemical properties and reduce the environmental adverse impacts. The PILs presented lower volatilization, higher photostability, better soil adsorption capacity, and improved fungicidal activity relative to pyrimethanil. When the length of the carbon chains in the anions was increased, the PILs showed better properties in terms of melting point, water solubility, volatility, and surface tension. The photostabilities and fungicidal activities of the PILs were significantly improved when cyclic compounds were used as the paired anion ions. With enhanced physicochemical properties and better fungicidal activity, PIL7 was selected as the best alternative to pyrimethanil. The intrinsic disadvantages of pyrimethanil could be surmounted using the system developed in the study; thus, ILs could have immense potential in the development of eco-friendly and efficient fungicides in the future.


Assuntos
Fungicidas Industriais/química , Líquidos Iônicos/química , Compostos Orgânicos/química , Pirimidinas/química , Adsorção , Ânions/química , Ânions/farmacologia , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Fungicidas Industriais/síntese química , Fungicidas Industriais/farmacologia , Líquidos Iônicos/farmacologia , Cinética , Compostos Orgânicos/farmacologia , Pirimidinas/farmacologia , Solo/química , Solubilidade , Volatilização
9.
Colloids Surf B Biointerfaces ; 178: 153-162, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-30856584

RESUMO

Based on the specific binding between the receptors and ligands, novel targeted nanocapsules were prepared by using silica covalently bonded with dopamine to increase the insecticidal efficacy of λ-cyhalothrin. The targeted release mechanism of λ-cyhalothrin nanocapsules (NC) nanocapsules was verified by enzymatic analysis, fluorescent marking method and high performance liquid chromatograph. The results showed NC had uniform particle size (800 nm) and approximately 31% (w/w) loading efficiency of λ-cyhalothrin. The stability of λ-cyhalothrin in nanocapsuels was improved under different pH and temperature conditions. The NC showed sustainable release properties and the release kinetics mainly belonged to Fickian diffusion at all experimental conditions. Compared to λ-cyhalothrin emulsifiable concentrate and microcapsule suspension, the NC exhibited more excellent insecticidal activity. The micronucleus test indicated that NC significantly reduced the genotoxicity of λ-cyhalothrin to non-target organisms. This work offers a novel and efficient way to use targeted drug delivery system to improve the insecticidal activity, and may be extended to other pesticides in the future.


Assuntos
Dopamina/química , Nanocápsulas/química , Nitrilas/química , Piretrinas/química , Dióxido de Silício/química , Inseticidas/química
10.
Sci Total Environ ; 670: 606-612, 2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-30909038

RESUMO

Triflumizole, a broad-spectrum systemic fungicide, has been widely used for the management of fungal diseases in plants. However, rapid photolysis and high risk to the aquatic environment limit its application. Ionic liquid (IL) forms of active pharmaceutical ingredients are innovative and promising agents that can optimize the application of the starting chemicals through the selection, or functionalization of the counterions (cation or anion). In this study, triflumizole was paired with various natural organic acids to develop novel ILs for improving the physicochemical properties and reducing the toxicity to fish. The results showed that the obtained ILs had low surface tension and lipophilicity and could protect triflumizole against degradation under UV irradiation as well as exhibit more excellent biological activity against Botrytis cinerea than triflumizole. The IL forms of triflumizole reduced the dosage and frequency of this fungicide, accordingly minimized the negative effect on environment. The IL contained salicylic acid as anion decreased > 4-fold toxicity to adult zebrafish over TFM. The results reported here create new application possibilities for imidazole fungicides and offer some heuristic rules for the design of active pharmaceutical ingredients-ionic liquids.


Assuntos
Fungicidas Industriais/toxicidade , Imidazóis/toxicidade , Poluentes Químicos da Água/toxicidade , Poluição da Água/prevenção & controle , Ânions , Líquidos Iônicos
11.
J Agric Food Chem ; 66(40): 10362-10368, 2018 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-30230823

RESUMO

Due to high volatility and water solubility, 2,4-dichlorophenoxyacetic acid (2,4-D) can easily enter into the atmosphere and water bodies by volatilization, drift, leaching, or runoff, which results in potential threats to the environment and human health. The physicochemical properties of pesticides can be regulated by preparing their ionic liquids. In this work, a series of dicationic ionic liquids (DILs) of 2,4-D were prepared to reduce its environmental risk and enhance herbicidal activity. The solubility, octanol-water partition coefficient, surface tension, and volatilization rate results of DILs showed that these properties could be optimized by choosing appropriate countercations. Compared to 2,4-D ammonium salt, DILs have lower volatility, water solubility, and surface tension as well as higher lipophilicity. Benefiting from optimized physicochemical properties, DILs HIL8-12 exhibited better herbicidal activity against three typical broadleaf weeds than 2,4-D ammonium salt, and their fresh weight inhibition rates increased by 2.74-46.84%. The safety assessment experiment indicated that DILs were safer to wheat than commercialized forms of 2,4-D. The DILs could reduce the environmental risk of 2,4-D caused by high volatility and water solubility and would be potential alternatives to its commercialized formulations.


Assuntos
Ácido 2,4-Diclorofenoxiacético/farmacologia , Herbicidas/farmacologia , Líquidos Iônicos/farmacologia , Ácido 2,4-Diclorofenoxiacético/química , Herbicidas/química , Líquidos Iônicos/química , Plantas Daninhas/efeitos dos fármacos , Plantas Daninhas/crescimento & desenvolvimento , Solubilidade , Volatilização
12.
J Agric Food Chem ; 66(36): 9418-9425, 2018 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-30133274

RESUMO

To elucidate the relationship between the structure of ionic liquid (IL) and its enrichment ability to trace pesticides from an environmental water sample, a series of imidazole-based ILs were synthesized to extract four fungicides (boscalid, cyprodinil, fluazinam, and pyrimethanil) through an in situ ionic liquid dispersive liquid-liquid microextraction method. The results showed that aromatic heterocyclic monocation ionic liquids (MILs) had better extraction ability to fungicides than other three alicyclic heterocyclic MILs. Dication ionic liquids (DILs) with the four carbons at the side chain had better ability to extract fungicides than MILs, and DILs with a long bridge carbon chain had better recoveries of fungicides with low Kow values. The proposed method showed high mean enrichment factors and high recoveries of the fungicides from real water samples. The rules of the relationship between the structure of IL and enrichment ability are instructive to the application of ILs in pretreatment of complex substances.


Assuntos
Fungicidas Industriais/isolamento & purificação , Líquidos Iônicos/química , Microextração em Fase Líquida/métodos , Poluentes Químicos da Água/isolamento & purificação , Fungicidas Industriais/química , Cinética , Poluentes Químicos da Água/química
13.
J Hazard Mater ; 358: 207-215, 2018 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-29990808

RESUMO

The frequent use of traditional copper-based microbicides has led to the growing risk of toxicity to non-target organisms in the environment. In this work, nanosilica was conjugated with copper(II) complexes of L-glutamate (or glycine) to develop novel copper-based microbicides with good microbicidal activity, systemicity and desired safety to plant, and the obtained nanosilica-L-glutamate copper complexes (Silica-Glu-Cu) and nanosilica-glycine copper complexes (Silica-Gly-Cu) were characterized and evaluated by FT-IR, SEM, TEM, and XPS. The results showed that Silica-Glu-Cu and Silica-Gly-Cu exhibited satisfactory activities and long effective periods against Phytophthora capsica and Botrytis cinereal and could move upward and downward freely in cucumber seedlings. Moreover, Silica-Glu-Cu increased the fresh weights of cucumber and wheat seedlings by 0.4-6.4% at the concentrations of 50-200 mg/L of copper. Thus, the novel copper-based microbicides can reduce the frequency of using copper-based bactericides and phytotoxicity to plants.


Assuntos
Complexos de Coordenação/farmacologia , Cobre/química , Desinfetantes/farmacologia , Ácido Glutâmico/química , Glicina/química , Nanoestruturas/química , Dióxido de Silício/química , Botrytis/efeitos dos fármacos , Complexos de Coordenação/química , Desinfetantes/química , Estrutura Molecular , Phytophthora/efeitos dos fármacos
14.
Sci Total Environ ; 640-641: 163-173, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-29859434

RESUMO

The massive release of rhodamine B (RhB) to water system is an emerging problem, which dramatically threaten environment and human health. The development of an adsorbent with enhanced removal efficiency for RhB is urgently needed. Herein, we report an environment-friendly synthesis of high quality zeolitic imidazolate framework-8 (ZIF-8) and functional ionic liquid@ZIF-8 in water-based system without heat treatment for improving its adsorption property. Guanidinium ionic liquids (ILs) could not only act as greener agents instead of volatile bases and toxic surfactants to efficiently control the nucleation and growth rate of ZIF-8, but also were incorporated as shell material to add specific adsorption sites. The relationship between nanoparticle structure and adsorption performance for RhB was systematically investigated. Due to high surface area (1167 m2 g-1), high porosity (0.79 cm3 g-1), high crystallinity, nano size (about 100 nm) and monodispersity, the as-obtained ZIF-8 showed improved adsorption capacity toward RhB (80% removal efficiency). Heteropolyanion-based guanidinium IL@meso-ZIF-8 (HPAIL@meso-ZIF-8) exhibited the high RhB uptake capacity of 278 mg g-1 (higher than most of the reported adsorbents) and effectively removed 99% of RhB within 15 min. The results showed that the adsorption process of prepared materials fitted well with pseudo-second-order kinetics and Langmuir isotherm model. The existence of mesopores in ZIF-8 facilitated the diffusion of RhB and the incorporated guanidinium IL played a significant role in enhancing the adsorption affinity. Moreover, the reusability results revealed the HPAIL@meso-ZIF-8 as a highly efficient adsorbent for RhB removal with satisfactory performance and structural stability. Therefore, HPAIL@meso-ZIF-8 is one of the most promising adsorbents for organic dye removal from water.

15.
Mater Sci Eng C Mater Biol Appl ; 89: 175-181, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29752087

RESUMO

Indole-3-butyric acid (IBA) is an efficient plant growth regulator for promoting germination and the formation of rooting of various plants. Since it is unstable and presents the low utilization ratio, there is a compelling need to design an environmentally friendly formulation for IBA, which can reduce the loss of degradation and improve its utilization. Nano-sized controlled-release formulations can provide better durability and penetrate through the plant epidermis to efficiently deliver the agrochemicals to the target tissues. In this work, a kind of novel nano controlled-release formulation was prepared by conjugating the IBA and 3-glycidoxypropyltrimethoxysilane (GPTMS) through a covalent cross-linking reaction, and subsequently hydrolyzation and polycondensation with tetraethoxysilane. The resulting nanospheres were characterized by Fourier transform infrared spectroscopy, ultraviolet spectrophotometry, scanning electron microscope, and thermal gravity analysis. The results showed that the obtained nanospheres had a remarkable loading efficiency of IBA (about 43% w/w). The formation of covalent between IBA and GPTMS enabled the nanospheres with a good chemical stability that could protect against photo-degradation effectively. The released rate of the IBA from nanospheres was related to the temperature, pH value. With increased temperature as well as acidity and alkality, the release of the IBA was sped up. The IBA could also be released effectively from IBA-silica nanospheres by esterase, and the sustainable release characteristics of IBA-silica nanospheres were in conformity with the Ritger and Peppas equation. The IBA-silica nanospheres displayed excellent dual stimuli-responsive properties under esterase and weak acid conditions, and could obviously promote the growth of root and bud of pea. Thus, the IBA silica nanospheres prepared by covalent cross-linking reaction have a good potential application as a controlled-release formulation and environmentally-friendly plant growth regulator.


Assuntos
Indóis/química , Nanosferas/química , Preparações de Ação Retardada , Esterases/metabolismo , Concentração de Íons de Hidrogênio , Luz , Microscopia Eletrônica de Varredura , Modelos Teóricos , Tamanho da Partícula , Dióxido de Silício/química , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Termogravimetria
16.
Anal Bioanal Chem ; 410(6): 1647-1656, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29294183

RESUMO

Five novel ionic liquids (ILs), 1,3-dibutylimidazolium bromide [BBMIm][Br], 1-pentyl-3-butylimidazolium bromide [BPMIm][Br], 1-hexyl-3-butylimidazolium bromide [BHMIm][Br], 1,1'-(butane-1,4-diyl)bis(3-butylimidazolium) bromide [C4(BMIm)2][Br2], and 1,1'-(butane-1,4-diyl)bis(3-methylimidazolium) bromide [C4(MIm)2][Br2], were prepared and used in situ to react with bis(trifluoromethane)sulfonamide lithium salt to extract the myclobutanil, tebuconazole, cyproconazole, and prothioconazole from water samples. The results showed that mono-cationic ILs had much better recovery than dicationic ILs, and mono-imidazolium IL bearing butyl groups at N-1 and N-3 sites had the best recovery. When the length of the alkyl substituent group was more than four carbons at N-3 site, the recovery decreased with increase of alkyl chain length of 1-butylimidazolium IL. The extraction efficiency order of triazoles from high to low was [BBMIm][Br], [BPMIm][Br], [BHMIm][Br], [BMIm][Br] (1-butyl-3-methylimidazolium bromide), [C4(BMIm)2]Br2, [C4(MIm)2]Br2. An in situ ionic liquid dispersive liquid-liquid microextraction combined with ultrasmall superparamagnetic Fe3O4 was established as a pretreatment method for enrichment of triazole fungicides in water samples by using the synthetic [BBMIm][Br] as the cationic IL and used to detect analytes followed by high-performance liquid chromatography. Under the optimized conditions, the proposed method showed a good linearity within a range of 5-250 µg L-1, with the determination coefficient (r2) varying from 0.998 to 0.999. High mean enrichment factors were achieved ranging from 187 to 323, and the recoveries of the target analytes from real water samples at spiking levels of 10.0, 20.0, and 50.0 µg L-1 were between 70.1% and 115.0%. The limits of detection for the analytes were 0.74-1.44 µg L-1, and the intra-day relative standard deviations varied from 5.23% to 8.65%. The proposed method can be further applied to analyze and monitor pesticides in other related samples. Graphical Abstract The scheme of the in-situ DLLME method for the determination of triazoles using the imidazolium-based ionic liquids.

17.
Sci Total Environ ; 616-617: 128-134, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29112836

RESUMO

As a widely used herbicide, picloram has been frequently detected in the aquatic environment due to its high leaching potential and low adsorption by soil. To reduce aquatic environmental risk of this herbicide caused by leaching and runoff, five herbicidal ionic liquids (HILs) based on picloram were prepared by pairing isopropylamine, octylamine, octadecylamine, 1-methylimidazole, 4-methylmorpholine respectively. Their physicochemical properties including water solubility, octanol-water partition coefficient, surface activity, leaching, as well as soil adsorption were compared. The results showed that these properties could be adjusted by appropriate selection of counter cations. The HILs with long alkyl chains in cations had low water solubility and leaching characteristics, good surface tension and lipophilicity, as well as high soil adsorption. Compared with currently used picloram in the forms of potassium salts, HIL3 had more excellent herbicidal activity against broadleaf weeds and may offer a lower use dosage. The HILs based on picloram can reduce its negative effects on the aquatic environment and can be used as a desirable alternative to commercial herbicidal formulations of picloram in future.


Assuntos
Herbicidas/química , Líquidos Iônicos/química , Picloram/química , Poluição Ambiental/prevenção & controle , Imidazóis , Morfolinas
18.
Carbohydr Polym ; 172: 322-331, 2017 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-28606541

RESUMO

Kasugamycin is an aminoglycoside antibiotic originally isolated from Streptomyces kasugaensis, which has been widely used for the management of plant diseases. However, photo-thermal instability and low efficiency limit its application. Therefore, it is an urgent task to prevent unwanted loss of kasugamycin and ensure maximum bioactivity at target site. In this work, a novel formulation of kasugamycin that responds to different biological stimuli produced by pests was prepared using silica microcapsules crosslinked with pectin via special disulfide bonds. The results demonstrated that the silica-SS-pectin microcapsules had a high loading efficiency (20% w/w) and could effectively enhance the thermal and light stability of kasugamycin. The microcapsules displayed excellent pectinase and glutathione dual-responsive properties and the release kinetics investigated by Riger-Peppas model suggested combination of various release mechanisms. Compared with kasugamycin wettable powder, the microcapsules possessed sustained and improved antimicrobial efficacy against Erwinia carotovora. Thus, the dual-responsive microcapsules potentially have agricultural application as a controlled release system.


Assuntos
Aminoglicosídeos/farmacologia , Anti-Infecciosos/farmacologia , Pectinas/química , Aminoglicosídeos/química , Anti-Infecciosos/química , Cápsulas , Portadores de Fármacos , Pectobacterium carotovorum/efeitos dos fármacos , Doenças das Plantas/prevenção & controle , Dióxido de Silício
19.
Anal Bioanal Chem ; 409(19): 4581-4592, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28585086

RESUMO

Due to the acidity and strong polarity of auxinic herbicides, separation of these compounds in food and environmental samples is a great challenge. In this study, 12 geminal dicationic ionic liquids (GDILs) were synthesized and used as mobile phase additives to separate six auxinic herbicides. The effects of the kind of dication, the length of linkage chain, the kind of anion, the concentration of GDILs, and the pH of mobile phase for the separation were investigated in detail. Compared with [C4MIm][BF4], GDILs ([C8(MIm)2][BF4]2) showed higher resolution, better peak shape, and lower retention factor. The separation performance of additives was in the order of [C8(MIm)2][BF4]2 > [C8(MPy)2][BF4]2, [(C4)2MPiz][BF4]2, [C8(MMo)2][BF4]2, [C4MIm][BF4], [C8(MPid)2][BF4]2 > [C8(HBOc)2][BF4]2 > TBAB. GDILs showed the best separation under the following conditions: cation: imidazolium; length of linkage chain: 8; anion: BF4-; mobile phase pH: 3; concentration: 5 mmol L-1. The separation mechanism of GDILs may mainly be due to their symmetric structure and the abundance of positive charge sites which could help GDILs shield the residual silanol and interact with analytes more efficiently to improve the peak shapes, resolution, and retention. In addition, the GDILs in the mobile phase and anions adsorbed on the stationary phase also greatly affected the separation. GDILs used as mobile phase additives to separate auxinic herbicides showed high efficiency separation and low damage to HPLC columns, and the developed chromatographic method had excellent linearity, accuracy, precision, and repeatability. The application and mechanism study of GDILs in HPLC would be instructive to determine and separate acid herbicides in food and environmental samples. Graphical abstract As HPLC mobile phase additives, GDILs show high separation performance due to their unique symmetric structures.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Líquidos Iônicos/análise , Cátions
20.
Anal Chim Acta ; 975: 20-29, 2017 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-28552303

RESUMO

In this work, in-situ ionic liquid dispersive liquid-liquid microextraction combined ultrasmall Fe3O4 magnetic nanoparticles was developed as a kind of pretreatment method to detect pyrethroid pesticides in water samples. New anion-exchange reagents including Na[DDTC] and Na[N(CN)2] were optimized for in-situ extraction pyrethroids, which showed enhanced microextraction performance. Pyrethroids were enriched by hydrophilic ionic liquid [P4448][Br] (aqueous solution, 200 µL, 0.2 mmol mL-1) reaction in-situ with anion-exchange reagent Na[N(CN)2] (aqueous solution, 300 µL, 0.2 mmol mL-1) forming hydrophobic ionic liquid as extraction agent in water sample (10 mL). Ultrasmall superparamagnetic iron oxide nanoparticles (30 mg) were used to collect the mixture of ionic liquid and pyrethroids followed by elution with acetonitrile. The extraction of ionic liquid strategies was unique and efficiently fulfilled with high enrichment factors (176-213) and good recoveries (80.20-117.31%). The method was successively applied to the determination of pyrethroid pesticides in different kinds of water samples with the limits of detection ranged from 0.16 to 0.21 µg L-1. The proposed method is actually nanometer-level microextraction (average size 80 nm) with the advantages of simplicity, rapidity, and sensitivity.

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