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1.
J Chromatogr A ; 1618: 460884, 2020 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-31973930

RESUMO

The facile preparation and characterization of a cationic polyelectrolyte (polydiallyldimethylammonium chloride, PDDA) fabricated graphene oxide-grafted silica microsphere (PDDA@GO@Sil) with high positive charge density as the sorbent for the high selective capture of acidic herbicides were reported. The theoretical calculation showed that there were strong adsorption energies between the PDDA and analytes, and the main interaction was the hydrogen bonding from OH…Cl and CO…HC. Static- and dynamic- state adsorption results indicated that acidic herbicides were the monolayer coverage onto the PDDA@GO@Sil due to the electrostatic attraction between the sorbent and analytes, and electrostatic repulsion among analytes. Under the optimized conditions obtained with the single-factor experiment and response surface methodology, this established method was used for the enrichment and determination of herbicides in two vegetables. Method detection limits were in the range of 0.75-1.50 µg L-1 indicating that the introduction of PDDA provided the excellent extraction capacity toward acidic herbicides. The obtained results exhibited that the developed method was feasible, reliable, selective and accurate for the determination of acidic herbicides in real samples.


Assuntos
Análise de Alimentos/métodos , Grafite/química , Herbicidas/análise , Herbicidas/isolamento & purificação , Polieletrólitos/química , Verduras/química , Adsorção , Ligação de Hidrogênio , Limite de Detecção , Dióxido de Silício/química , Extração em Fase Sólida
2.
J Chromatogr A ; 1617: 460819, 2020 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-31898947

RESUMO

Polymers obtained from tetraethyl orthosilicate (TEOS) and triethoxymethylsilane (MTEOS) have been functionalized with different metal and metal oxide nanoparticles (NPs), and used as coatings of extractive capillaries for the extraction of polar compounds by in-tube solid-phase microextraction (IT-SPME) coupled on-line to nano-liquid chromatography (nano-LC). The extraction capabilities of the new phases have been studied using several triazinic herbicides with log of octanol/water partition coefficients (Kow) ranging from -0.7 to 3.21 under reversed phase chromatographic conditions. Best extraction efficiencies for the most polar compounds (log Kow ≤ 2.3) were typically obtained with the CuO NPs doped phase. The TEOS-MTEOS polymer can be modified with two types of NPs in order to obtain extractive phases capable of interacting with compounds of a wide range of polarities; alternatively, two capillaries each with a different type of NPs can be combined in series with the same goal. Under the later approach the limits of detection (LODs) found for the tested herbicides were 0.02-1.5 µg/L, and the precision expressed as relative standard deviation (RSD) varied from 2 to 10% (n = 3). The recoveries found in sea water samples ranged from 80 to 107%. In addition, the developed CuO NPs doped phase can be used in hydrophilic interaction chromatography (HILIC), which is the separation mode recommended for highly polar compounds. This has been illustrated using the amino acids tyrosine (log Kow = -2.26) and tryptophan (log Kow = -1.06) as model compounds, being their respective LOD 0.1 and 0.3 µg/mL. Examples of application of the developed bimodal extractive phase to different environmental and waste waters are given in order to show its utility and versatility.


Assuntos
Cromatografia Líquida/métodos , Cobre/química , Nanopartículas Metálicas/química , Microextração em Fase Sólida/métodos , Cromatografia de Fase Reversa , Herbicidas/análise , Herbicidas/isolamento & purificação , Interações Hidrofóbicas e Hidrofílicas , Limite de Detecção , Polímeros/química , Água do Mar/química , Silanos/química , Triazinas/análise , Triazinas/isolamento & purificação , Triptofano/análise , Tirosina/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/isolamento & purificação
3.
J Chromatogr A ; 1617: 460829, 2020 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-31902576

RESUMO

In this study, a new automated magnetic micro solid-phase extraction was introduced. A Tygon tube was folded and fixed around the pole of a cylindrical magnet. Nanosized magnetic sorbents modified with diphenyldichlorosilane were uniformly immobilized on one side of the inner wall of the tube. Sample solution and desorption solvent were passed through the tube using a peristaltic pump. Four phenylurea herbicides (tebuthiuron, monolinuron, isoproturon, and monuron) were used as the model compounds to evaluate the method performance. HPLC-UV was used to separate and quantify the analytes. The effective parameters influencing the performance of the extraction process (i.e., extraction and desorption flow rates, eluent and sample volumes, type of eluent and sample ionic strength) were investigated. The limit of detection was 0.04 µg L-1 for all studied compounds. Calibration curves were linear in the range of 0.1-500 µg L-1 with a determination coefficient between 0.9988 and 0.9999. Intra-day, inter-day and batch-to-batch precisions expressed as relative standard deviation were less than 7%. Several environmental water samples were investigated to assess the applicability of the method for real sample analysis.


Assuntos
Cromatografia Líquida de Alta Pressão , Herbicidas/análise , Compostos de Fenilureia/análise , Microextração em Fase Sólida/métodos , Poluentes Químicos da Água/análise , Herbicidas/isolamento & purificação , Linurona/análogos & derivados , Linurona/análise , Linurona/isolamento & purificação , Fenômenos Magnéticos , Compostos de Metilureia/análise , Compostos de Metilureia/isolamento & purificação , Compostos de Fenilureia/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação
4.
Ecotoxicol Environ Saf ; 190: 110180, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31927195

RESUMO

This paper studied the allelopathic effect of Cylindrotheca closterium on the growth of Prorocentrum donghaiense, the model of harmful algal blooms in aquatic environment, by the co-culture tests and bioassay-guided fraction methods. The growth of P. donghaiense in co-cultures was observably suppressed by C. closterium, and P. donghaiense biomass in C/P = 3: 1 group increased slowly with a low growth rate of 0.18 d-1 after 4 days. Petroleum ether (PE) extract derived from C. closterium filtrates was isolated by C18 column and the allelopathy of all isolated fractions for P. donghaiense was investigated. After 96 h cultivation, the inhibition ratio of PE-Ⅲ and PE-Ⅷ fractions on P. donghaiense could reach up to 70.2% and 64.3% at the concentration of 10-fold when compared to control, while the other fractions displayed relatively low inhibitory effects on P. donghaiense. PE-Ⅲ and PE-Ⅷ fractions also decreased the chlorophyll content and maximum quantum yield of photosystem II (Fv/Fm) of P. donghaiense cells. The activities of superoxide dismutase (SOD), one of antioxidant enzymes, reduced around 8.3% and 13.7% following exposure to 2-fold PE-Ⅲ and PE-Ⅷ, and was significantly decreased following higher exposure concentrations. After 96 h of 10-fold PE-Ⅲ and PE-Ⅷ treatments, Catalase (CAT) activity reduced to 44.86% and 46.42% of that observed in the control group. At the same time, a significant increase in malondialdehyde (MDA) contents was observed. These findings suggested that PE-Ⅲ and PE-Ⅷ fractions contained main allelochemicals and possibly acted as promising algistatic agents for emergency handling of P. donghaiense blooms.


Assuntos
Diatomáceas/química , Dinoflagelados/efeitos dos fármacos , Proliferação Nociva de Algas/efeitos dos fármacos , Herbicidas/farmacologia , Feromônios/farmacologia , Alelopatia , Biomassa , Clorofila/metabolismo , Dinoflagelados/crescimento & desenvolvimento , Herbicidas/isolamento & purificação , Feromônios/isolamento & purificação , Complexo de Proteína do Fotossistema II/metabolismo
5.
J Chromatogr A ; 1614: 460728, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31785896

RESUMO

Triazine rings-containing porous aromatic framework (PAF-56p) was synthesized through a Friedel-Crafts reaction and investigated as a coating for the stir bar sorptive extraction (SBSE) of interest triazines. The triazine rings and conjugated groups in PAF-56p could interact with triazine rings-containing herbicides by hydrophobic and π-π interactions. The PAF-56p coated stir bar showed superior extraction performance over commercial PDMS and EG coated stir bar in terms of extraction efficiency and dynamics towards six triazine herbicides with different polarity. Based on it, a method by combining PAF-56p-SBSE with high performance liquid chromatography (HPLC)-diode array detector (DAD) was established for the analysis of six target triazine herbicides, including simazine, atrazine, ametryn, prometon, prometryne and prebane. The affecting factors of SBSE were investigated by single-factor test. Under the optimized conditions, the limits of detection of the proposed method were ranged from 0.037 to 0.089 µg/L with the linear range within 0.1-200 µg/L for six triazine herbicides. High enrichment factors (EFs) of 61.8-89.5-fold (theoretical EF is 100-fold) were achieved. The developed PAF-56p-SBSE-HPLC-DAD method was successfully applied for trace triazine herbicides analysis in maize and maize leaf samples, with recoveries in the range of 86.5-115% and 85.1-114% for spiked maize and maize leaf samples, respectively.


Assuntos
Técnicas de Química Analítica/métodos , Cromatografia Líquida de Alta Pressão , Herbicidas/análise , Triazinas/análise , Zea mays/química , Técnicas de Química Analítica/instrumentação , Herbicidas/isolamento & purificação , Limite de Detecção , Porosidade , Reprodutibilidade dos Testes , Triazinas/isolamento & purificação
6.
J Chromatogr A ; 1613: 460672, 2020 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-31727353

RESUMO

In the present study, porous monolith-based magnetism-reinforced in-tube solid phase microextraction (MB-MR/IT-SPME) was first introduced to concentrate sulfonylurea herbicides (SUHs). To realize the effective capture of SUHs, a monolithic capillary microextraction column (MCMC) based on poly (vinylimidazole-co-ethylene dimethacrylate) polymer doped with Fe3O4 magnetic nanoparticles was in-situ synthesized in the first step. After that, the MCMC was twined with a magnetic coil which was employed to carry out variable magnetic field during adsorption and desorption procedure. Various important parameters that affecting the extraction performance were inspected in detailed. Results well indicated that exertion of magnetic field in the whole extraction procedure was in favor of the capture and release of the studied SUHs, with the extraction efficiencies increased from 36.8-58.1% to 82.6-94.5%. At the same time, the proposed MB-MR/IT-SPME was online combined to HPLC with diode array detection (HPLC/DAD) to quantify trace levels of SUHs in water and soil samples. The limits of detection (S/N = 3) for water and soil samples were in the ranges of 0.030-0.15 µg/L and 0.30-1.5 µg/kg, respectively. The relative standard deviations (RSDs) for intra- and inter-day variability were both less than 10%. Finally, the introduced approach was successfully applied to monitor the low contents of studied SUHs in environmental water and soil samples. Satisfying fortified recovery and precision were achieved.


Assuntos
Monitoramento Ambiental/métodos , Herbicidas/análise , Solo/química , Microextração em Fase Sólida , Água/química , Cromatografia Líquida de Alta Pressão , Herbicidas/isolamento & purificação , Magnetismo , Polímeros , Porosidade , Compostos de Sulfonilureia/isolamento & purificação , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/isolamento & purificação
7.
J Sci Food Agric ; 100(3): 1185-1194, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31680262

RESUMO

BACKGROUND: Ludwigia hyssopifolia (G. Don) Exell, one of the problem weeds in some rice-producing countries, was studied to determine its allelopathic potential based on the effects of aqueous extracts of its tissues (leaves, roots and stem) on seedling growth of selected weeds and rice. The major phenolic compound of its leaves was also isolated and characterized. RESULTS: L. hyssopifolia aqueous leaf extract showed significant inhibition of shoot growth and biomass accumulation of weeds (Amaranthus spinosus L., Dactyloctenium aegyptium L., Cyperus iria L.) while maintaining less adverse effects on rice (crop) compared to other aqueous extracts of roots and stem. Phytochemical screening showed that phenols, tannins, flavonoids, terpenoids, saponins and coumarins are found in its leaf aqueous extract. The Folin-Ciocalteu method revealed that its leaves contain 26.66 ± 0.30 mg GAE g-1 leaf. The extract was then acid-hydrolyzed to liberate the phenolics (25 mg phenolics g-1 leaf). The major compound was isolated via preparative thin-layer chromatography using formic acid-ethyl acetate-n-hexane (0.05:4:6) solvent system. It had maximum UV absorption at 272 nm while its Fourier transform infrared spectrum revealed phenol, carboxylic acid and ether functionalities. This also had similar chromatographic mobility when run together with syringic acid in two-dimensional paper chromatography and thin-layer chromatography. CONCLUSIONS: L. hyssopifolia has potential allelopathic activity and its leaf aqueous extract showed the highest phytotoxic activity (P ≤ 0.05) indicating its potential as a bioherbicide. The most probable identity of the major phenolic compound is syringic acid. © 2019 Society of Chemical Industry.


Assuntos
Herbicidas/química , Onagraceae/química , Extratos Vegetais/química , Amaranthus/efeitos dos fármacos , Amaranthus/crescimento & desenvolvimento , Flavonoides/química , Flavonoides/isolamento & purificação , Flavonoides/farmacologia , Herbicidas/isolamento & purificação , Herbicidas/farmacologia , Fenóis/química , Fenóis/isolamento & purificação , Fenóis/farmacologia , Compostos Fitoquímicos/química , Compostos Fitoquímicos/isolamento & purificação , Compostos Fitoquímicos/farmacologia , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Folhas de Planta/química , Plantas Daninhas/efeitos dos fármacos , Plantas Daninhas/crescimento & desenvolvimento , Taninos/química , Taninos/farmacologia
8.
J Chromatogr A ; 1610: 460552, 2020 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-31547959

RESUMO

In this work, the Dubsky's model proposed for Capillary Electrophoresis (CE) enantioseparation systems with a mixture of chiral selectors was applied to the rapid optimization of the simultaneous enantiomeric separation of a multicomponent mixture of six phenoxy acid herbicides using a dual system of two cyclodextrins (CDs), (2-hydroxypropyl)-ß-CD (HP-ß-CD) and heptakis(2,3,6-tri-O-methyl)-ß-CD (TM-ß-CD). Simply by carrying out a small number of individual experiments separately with each CD, the Dubsky's model enabled to foresee the results that could be obtained for any possible combination of concentrations and relative proportion of both CDs in the mixture. Results obtained in this work demonstrated that the model was successful by improving the previous results experimentally obtained by the trial and error method for the simultaneous enantiomeric separation of the six phenoxy acid herbicides studied in this work. In fact, the separation was improved in terms of enantiomeric resolutions obtained (from 1.2 to 4.2 for concentrations of CDs of 4 mM HP-ß-CD and 16 mM TM-ß-CD) and by considerably reducing the time to optimize the separation conditions enabling to find, in a faster and efficient way, the most adequate proportion of both CDs and the concentration of each CD in the mixture to obtain baseline separation of the twelve enantiomers. Additionally, the apparent complexation constants between enantiomers and each CD were calculated. This is the first time that the above-mentioned model was applied to a multicomponent mixture of chiral compounds.


Assuntos
Ciclodextrinas/química , Eletroforese Capilar/métodos , Herbicidas/química , Herbicidas/isolamento & purificação , 2-Hidroxipropil-beta-Ciclodextrina/química , Estereoisomerismo
9.
Nat Prod Res ; 34(6): 773-781, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30445848

RESUMO

New allelochemicals were identified through bio-guided fractionation from the ethyl acetate of seeds extracts, which was the most autotoxic compared to the other plant parts. Phytochemical investigation of the seeds extracts of C. arabica by spectroscopy analyses has led to identify two new dammarane type triterpenes (4 and 9), with nine known analogues (1 - 3, 5 - 8, 10 and 11), a new cucurbitane triterpene (12), acylated dehydrodiconiferyl alcohol (13), and three highly oxygenated flavonols (14-16). The most autotoxic compounds on germination and seedling growth were elucidated as dammarane type triterpenes. However, less autotoxic effect was recorded by an inhibition under 50% for most of the identified flavonoids. These results suggest that those autotoxic substances may be used as a new bio-herbicide that may contribute to manage the distribution of C. arabica in agronomic field.[Formula: see text].


Assuntos
Cleome/efeitos dos fármacos , Herbicidas/isolamento & purificação , Feromônios/farmacologia , Triterpenos/isolamento & purificação , Flavonóis/isolamento & purificação , Germinação/efeitos dos fármacos , Glicosídeos/isolamento & purificação , Herbicidas/química , Extratos Vegetais/química , Plântula/efeitos dos fármacos , Sementes/química , Triterpenos/química , Triterpenos/farmacologia
10.
Nat Prod Res ; 34(6): 843-846, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30398363

RESUMO

Chemical constitutes and phytotoxic activity of Cuminum cymiunm L. is investigated in the present study. For this means seeds of C. cyminum L. was harvested from Ilkhchi of Iran. The major components of essential oil (EO) with more than 94% were 3-caren-10-al, cuminal, 2-Caren-10-al, γ-Terpinene, (-)-ß-Pinene and p-Cymene. This study found that cumin EO displayed meaningful inhibitory impacts on germination indices and the growth of the seedlings of Amaranthus retroflexus, Lactuca sativa, and Acroptilon repens. The germination indices showed severely concentration-dependent responses. In the case of A. retroflexus and L. sativa germination indices were controlled in the 500 ppm and in the A. repens were inhibited in the 1500 ppm of EO concentration. Overall, this study suggests that EO derived from C. cyminum L. looks to be a promising candidate for its utilization as a natural herbicide in large scale.[Formula: see text].


Assuntos
Cuminum/química , Herbicidas/isolamento & purificação , Monoterpenos/isolamento & purificação , Óleos Voláteis/isolamento & purificação , Oxigênio/química , Plântula , Amaranthus/efeitos dos fármacos , Germinação/efeitos dos fármacos , Herbicidas/toxicidade , Irã (Geográfico) , Monoterpenos/farmacologia , Monoterpenos/toxicidade , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Óleos Voláteis/toxicidade , Plântula/efeitos dos fármacos , Sementes/efeitos dos fármacos
11.
Food Chem ; 309: 125618, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31767479

RESUMO

In this study, a porous organic polymer (denoted as Car-DMB) was fabricated by a simple one-step crosslinking polymerization of carbazole and p-dimethoxybenzene for the first time. Then the Car-DMB was served as adsorbent of solid phase extraction to enrich triazine herbicides from white gourd, tomato and soybean milk samples prior to their determination by high performance liquid chromatography. Under the optimal conditions, the response linearity was in the range of 0.3-100.0 ng g-1 for white gourds and tomato samples, and 0.5-100.0 ng mL-1 for soybean milk, with the coefficient of determination higher than 0.996. The detection limits were 0.1-0.2 ng g-1 for white gourd and tomato samples, and 0.15-0.3 ng mL-1 for soybean milk. The adsorption mechanism of the Car-DMB for the triazines was attributed to the strong H-bonding and weak π-π interactions. The efficient extraction for several other compounds demonstrated that Car-DMB holds great potential for diverse analysis applications.


Assuntos
Herbicidas/isolamento & purificação , Polímeros/química , Extração em Fase Sólida/métodos , Triazinas/isolamento & purificação , Verduras/química , Adsorção , Anisóis/química , Carbazóis/química , Cromatografia Líquida de Alta Pressão , Reagentes para Ligações Cruzadas/química , Teoria da Densidade Funcional , Análise de Alimentos/métodos , Herbicidas/análise , Limite de Detecção , Nanotubos de Carbono/química , Polímeros/síntese química , Poliestirenos/química , Porosidade , Extração em Fase Sólida/instrumentação , Triazinas/análise
12.
Anal Chim Acta ; 1093: 160-167, 2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31735210

RESUMO

In this study, poly(butyl methacrylate-co-ethyleneglycol dimethacrylate) polymeric monoliths were in situ developed within 0.75 mm i.d. poly(ethylene-co-tetrafluoroethylene) (ETFE) tubing by UV polymerization via three different free-radical initiators (α,α'-azobisisobutyronitrile (AIBN), 2,2-dimethoxy-2-phenylacetophenone (DMPA) and 2-methyl-4'-(methylthio)-2-morpholinopropiophenone (MTMPP). The influence of the nature of each photo-initiator and irradiation time on the morphological features of the polymer was investigated by scanning electron microscopy, and the chromatographic properties of the resulting microbore columns were evaluated using alkyl benzenes as test substances. The beds photo-initiated with MTMPP gave the best performance (minimum plate heights of 38 µm for alkyl benzenes) and exhibited a satisfactory reproducibility in the chromatographic parameters (RSD < 11%). These monolithic columns were also successfully applied to the separation of phenylurea herbicides, proteins and a tryptic digest of ß-casein.


Assuntos
Acetofenonas/química , Cromatografia Líquida de Alta Pressão/instrumentação , Morfolinas/química , Nitrilos/química , Ácidos Polimetacrílicos/química , Politetrafluoretileno/análogos & derivados , Propiofenonas/química , Acetofenonas/efeitos da radiação , Caseínas/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Herbicidas/isolamento & purificação , Metacrilatos/química , Morfolinas/efeitos da radiação , Nitrilos/efeitos da radiação , Fragmentos de Peptídeos/isolamento & purificação , Compostos de Fenilureia/isolamento & purificação , Polimerização , Ácidos Polimetacrílicos/síntese química , Politetrafluoretileno/química , Propiofenonas/efeitos da radiação , Raios Ultravioleta
13.
J Environ Sci Health B ; 55(4): 361-375, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31880197

RESUMO

Activated carbons are well-known porous materials as an effective adsorbent used for the removal of emerging contaminants, such as herbicides, which are increasingly present in water bodies. Most water treatment plants, specially in Brazil, are unable to completely remove such contaminants by the conventional process and advanced treatment using activated carbons is required. The aim of this paper was to verify the influence of the activated carbons granulometry and specific surface area on the 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide removal efficiency using distilled-deionized water and filtered water collected from a conventional Water Treatment Plant. Commercial activated carbons samples used in this work were obtained from two different manufacturers. Activated carbons were analyzed by the specific surface area, pore size and volume distribution, nuclear magnetic resonance, infrared and x-ray spectroscopy, moisture, volatile matter and ash contents. Batch adsorption isotherms experiments were used and performed by Langmuir and Freundlich models. Granular and powdered activated carbons removed over 99% of 2,4-D in distilled water and near to 99% using filtered water. The activated carbons evaluated in this work presented high performance and played a key role in water treatment by removing 2,4-D herbicide, ensuring the protection of human health and the ecosystem.


Assuntos
Ácido 2,4-Diclorofenoxiacético/isolamento & purificação , Carvão Vegetal/química , Herbicidas/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Ácido 2,4-Diclorofenoxiacético/química , Adsorção , Brasil , Herbicidas/química , Espectroscopia de Ressonância Magnética , Espectroscopia de Infravermelho com Transformada de Fourier , Água/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Difração de Raios X
14.
Mikrochim Acta ; 186(12): 761, 2019 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-31712903

RESUMO

Metal-organic coordination polymer beads (MOCBs) are described for use as a sorbent for solid-phase extraction of chlorophenoxy herbides. By applying regulation of Co(II) ions, micro-sized monodisperse MOCBs were obtained through the microwave heating. The MOCBs-based method displays excellent extraction efficiency towards chlorophenoxy herbicides, specifically of 2-chlorophenoxyacetic acid, 4-chlorophenoxyacetic acid, 4-chloromethylphenoxyacetic acid, 2,4-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid and 2-(2,4-dichlorophenoxy)propionic acid. Following extraction, the herbicides were eluted with 8% formic acid in methanol and quantified by HPLC. The method, when applied to analyze spiked cereals, exhibits a wide linear range (from 0.6 to 1000 ng g-1) and low limits of quantification (ranging from 0.10 to 0.25 ng g-1). For a single column, the inter-day and intra-day precisions, expressed as the relative standard deviation are in the range of 2.5-6.8%. The batch-to-batch reproducibility (for n = 3) is <4.6%. For spiked cereal samples, relative recoveries are very good (90.3-102.3%, for n = 4). The extraction efficiency of MOCBs remains unchanged after reusing for 40 times. Graphical abstractSchematic presentation of Co(II)-doped metal-organic coordination polymer beads (Co(II)@MOCB) using for solid-phase extraction (SPE).


Assuntos
Ácido 2,4-Diclorofenoxiacético/análogos & derivados , Ácido 2,4-Diclorofenoxiacético/isolamento & purificação , Herbicidas/isolamento & purificação , Estruturas Metalorgânicas/química , Extração em Fase Sólida/métodos , Ácido 2,4-Diclorofenoxiacético/análise , Adsorção , Cromatografia Líquida de Alta Pressão , Cobalto/química , Grão Comestível/química , Contaminação de Alimentos/análise , Herbicidas/análise , Herbicidas/química , Limite de Detecção , Magnoliopsida/química , Estruturas Metalorgânicas/síntese química , Reprodutibilidade dos Testes
15.
Artigo em Inglês | MEDLINE | ID: mdl-31618815

RESUMO

Microbial electrochemical technology provides an inexhaustible supply of electron acceptors, allowing electroactive microorganisms to generate biocurrent and accelerate the removal of organics. The treatment of wastewater contaminated by butachlor, which is a commonly used chloroacetamide herbicide in paddy fields, is a problem in agricultural production. In this study, butachlor was found to be removed efficiently (90 ± 1%) and rapidly (one day) in constructed single-chamber microbial fuel cells (MFCs). After the addition of sodium acetate to MFCs with butachlor as the sole carbon source, electricity generation was recovered instead of increasing the degradation efficiency of butachlor. Meanwhile, the microbial community structure was changed in anodic and cathodic biofilms after the addition of butachlor, following the bioelectrochemical degradation of butachlor. High-throughput sequencing showed the proliferation of Paracoccus and Geobacter in MFCs with butachlor as the sole carbon source and of Thauera butanivorans in MFCs with butachlor and sodium acetate as concomitant carbon sources. These species possess the ability to oxidize different substituents of butachlor and have important potential use for the bioremediation of wastewater, sediments, and soils.


Assuntos
Acetanilidas/isolamento & purificação , Fontes de Energia Bioelétrica , Herbicidas/isolamento & purificação , Microbiota , Biodegradação Ambiental , Biofilmes , Eletrodos , Ensaios de Triagem em Larga Escala , Águas Residuárias/química
16.
Environ Pollut ; 255(Pt 1): 113150, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31541823

RESUMO

Excessive pesticide residues in the environment have caused more and more serious social problems. In this article, the polymer materials and graphene oxide were smoothly grafted together through surface-initiated atom-transfer radical polymerization. A temperature and pH dual-sensitive adsorbent was successfully obtained, which was used for the removal of six sulfonylurea herbicides in the aquatic environment. Experiment results showed that the adsorbent could efficiently remove the tested pesticides in aqueous solution rapidly (only 1 min). The adsorption process was in consist with the pseudo-second-order kinetics equation and Freundlich model, and the thermodynamic parameters were also calculated. Furthermore, the mechanism for removal performance was judged as n-π, π-π, hydrogen bonding, hydrophobic and electrostatic interaction verdict. Exhilaratingly, the material showed no significant toxicity to Daphnia magna on risk assessment.


Assuntos
Grafite/química , Herbicidas/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Animais , Daphnia/efeitos dos fármacos , Herbicidas/química , Herbicidas/toxicidade , Concentração de Íons de Hidrogênio , Cinética , Temperatura , Termodinâmica , Poluentes Químicos da Água/química
17.
J Sep Sci ; 42(22): 3459-3469, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31524319

RESUMO

The herbicides in naked oat (Avena nuda L.) samples were extracted, separated, and determined by using ionic-liquid-based matrix solid-phase dispersion-solvent flotation coupled with high-performance liquid chromatography. The experimental parameters were optimized and evaluated by a univariate method and orthogonal experiment. A good linear relationship was obtained in the range of 5-5000 µg/kg, and the linear correlation coefficient are between 0.9989∼0.9993. The quantification limits for alachlor, metazachlor, propanil, acetochlor, pretilachlor, metolachlor, and butachlor are 5.03, 2.62, 2.73, 4.58, 7.28, 5.05, 5.78 µg/kg, respectively. The average recoveries of the acetanilide herbicides at spiked concentrations of 10, 100, and 500 µg/kg ranged from 92.1 to 104.7%, and relative standard deviations were equal to or lower than 2.9%.


Assuntos
Acetanilidas/isolamento & purificação , Avena/química , Herbicidas/isolamento & purificação , Líquidos Iônicos/química , Extração em Fase Sólida , Acetanilidas/química , Herbicidas/química
18.
PLoS One ; 14(9): e0222933, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31545849

RESUMO

Bioactive herbicidal compounds produced by soil microorganisms might be used to creating a bioherbicide for biological weed control. A total of 1,300 bacterial strains were isolated and screened for herbicidal activity against grass and broadleaf weeds. Among primarily selected 102 strains, the herbicidal activity of bacterial fermentation broths from the following three isolates strain-101, strain-128, and strain-329 reduced the growth of D. sanguinalis by 66.7%, 78.3%, and 100%, respectively as compared with control. Phylogenetic analysis of 16S rRNA gene sequencing determined that the strain-329 has 99% similarity to Streptomyces anulatus (HBUM 174206). The potential bioherbicidal efficacy of Streptomyces strain-329 was tested on grass and broadleaf weeds for phytotoxic activity through pre- and post-emergence applications. At pre-emergence application, the phytotoxic efficacy to D. sanguinalis and S. bicolor on seed germination were 90.4% and 81.3%, respectively at the 2x concentration, whereas in the case of Solanum nigrum, 85.2% phytotoxic efficacy was observed at the 4x concentration. The efficacy of Streptomyces strain-329 was substantially higher at post-emergence application, presenting 100% control of grass and broadleaf weeds at the 1x concentration. Two herbicidal compounds coded as 329-C1 and 329-C3 were extracted and purified by column chromatography and high-performance liquid chromatography methods. The active compound 329-C3 slightly increased leaf electrolytic leakage and MDA production as concentration-dependent manner. These results suggest that new Streptomyces sp. strain-329 produced bioherbicidal metabolites and may provide a new lead molecule for production an efficient bioherbicide to regulate grass and broadleaf weeds.


Assuntos
Fermentação , Herbicidas/metabolismo , Plantas Daninhas/crescimento & desenvolvimento , Poaceae/genética , Streptomyces/química , Cromatografia Líquida de Alta Pressão , Herbicidas/isolamento & purificação , Herbicidas/farmacologia , Filogenia , Plantas Daninhas/classificação , Plantas Daninhas/efeitos dos fármacos , Poaceae/classificação , Poaceae/efeitos dos fármacos , RNA Ribossômico 16S/genética , Especificidade da Espécie , Streptomyces/classificação , Streptomyces/genética , Controle de Plantas Daninhas/métodos
19.
Environ Toxicol Chem ; 38(12): 2614-2620, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31499576

RESUMO

An accurate and sensitive method has been developed for determination of the herbicide isoproturon using the Quick Easy Cheap Effective Rugged Safe (QuEChERS) extraction-spectrofluorimetric technique. The method involves the reaction of 2-cyanoacetamide with isoproturon in basic medium (NH3 ; 15 mol/L). The resulting fluorescent product was found to show maximum emission at 378 nm and maximum excitation at 333 nm. Fluorescence intensity under the influence of different parameters was investigated. The linear range of analyte concentrations was found to be 0.5 to 15 µg/mL, with a limit of detection of 0.144 µg/mL, a limit of quantification of 0.437 µg/mL (signal to noise ratio = 3), and a regression coefficient of 0.9991, under optimized conditions. The proposed method was effectively applied for determination of isoproturon in different matrices; the percentage of recovery varied from 85.00 ± 1.2% to 96.00 ± 0.5%. The method was also applied for residue analysis of isoproturon in real soil samples collected from a pilot field. For extraction of isoproturon, the QuEChERS extraction approach was used, and the average residue in the soil samples was found to be 0.81 ± 0.07 µg/g. To show the potential of this approach, our results were compared with those of other methods reported in the literature. Environ Toxicol Chem 2019;38:2614-2620. © 2019 SETAC.


Assuntos
Fracionamento Químico/métodos , Herbicidas/análise , Herbicidas/isolamento & purificação , Compostos de Fenilureia/análise , Compostos de Fenilureia/isolamento & purificação , Espectrometria de Fluorescência/métodos , Poluentes do Solo/análise , Poluentes do Solo/isolamento & purificação
20.
Artigo em Inglês | MEDLINE | ID: mdl-31479387

RESUMO

An extraction method based on metal-organic framework has been developed and applied to acetanilide herbicides, including metazachlor, propanil, pretilachlor, and butachlor, in black beans, red beans, and kidney beans. The acetanilide herbicides are extracted with a mixture of ethyl acetate and n-hexane. The extract solution is absorbed and purified with metal-organic framework MIL-101 (Zn). The separation and determination of four acetanilide herbicides were implemented by high-performance liquid chromatography. The experimental parameters were evaluated by a univariate method and orthogonal experiments. The presented method can obtain effective extraction and purification. The detection limits for metazachlor, propanil, pretilachlor, and butachlor were 0.58, 0.90, 1.78 and 1.18 µg/kg, respectively. The average recoveries of the acetanilide herbicides at spiked concentrations of 10, 50, and 100 µg/kg ranged from 86.9% to 119.0%, and relative standard deviations were equal to or lower than 2.80%.


Assuntos
Acetanilidas/isolamento & purificação , Herbicidas/isolamento & purificação , Estruturas Metalorgânicas/química , Acetanilidas/química , Acetatos/química , Adsorção , Animais , Canavalia/química , Herbicidas/química , Hexanos/química , Tamanho da Partícula , Phaseolus/química
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