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1.
J Chromatogr A ; : 460950, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-32061359

RESUMO

It is necessary to establish a rapid, simple and environmentally friendly detection method for benzoylurea pesticides (BUs) in environmental water samples because of their toxicity in environmental circulation. Herein, a novel polyethylene glycol (PEG) modified magnetic covalent organic framework material based on the Schiff base reaction was prepared (PEG/Fe3O4@SNW-1). This material was used as a sorbent for enriching five BUs by magnetic solid phase extraction prior to detection via high-performance liquid chromatography. After the optimization of several parameters (such as the salinity, extraction time, amount of sorbent, desorption time, etc.) that influenced the recovery of the magnetic solid phase extraction process, the limits of detection (S/N = 3) were defined as less than 1.0 µg L-1, and the limits of quantitation (S/N = 10) were calculated as being lower than 3.4 µg L-1. A satisfactory linear range of 5-1000 µg L-1 was achieved. Finally, the proposed method was applied to analyze benzoylurea pesticides in three environmental water samples. These results indicated that the proposed method was feasible and demonstrated the potential application of the PEG/Fe3O4@SNW-1 material for detecting similar pesticide residues in environmental water samples.

2.
Artigo em Inglês | MEDLINE | ID: mdl-32058316

RESUMO

In this study, low-density deep eutectic solvent combined with dispersive liquid-liquid microextraction was applied to the extraction of five benzoylurea insecticides (BUs, including diflubenzuron, triflumuron, hexaflumuron, flufenoxuron, and chlorfluazuron) from beverages. Then the extracted and concentrated samples were analyzed and detected using the high-performance liquid chromatography combined with an ultraviolet detector. The DESs were synthesized by [P14,6,6,6]Cl as hydrogen bond acceptor and tetradecyl alcohol as hydrogen bond donor, and then characterized by Fourier transform infrared spectroscopy. In the experiment, the key factors affecting the extraction efficiency were screened by Plackett-Burman design and optimized with the central composite design. The extraction recovery rates were 85.91-95.12%. The limits of detection and correlation coefficients of the method were 0.30-0.60 µg L-1 and 0.9992-0.9997. Finally, the method was applied to determine the BUs in four beverage samples, and satisfactory recoveries, within the range of 76.87-101.19% were achieved. The present method has the potential to be applied to the detection of BUs in aqueous samples.

3.
Artigo em Inglês | MEDLINE | ID: mdl-31963490

RESUMO

Based on survey data from 327 rural households in the areas affected by the Wenchuan Earthquake and Lushan Earthquake in Sichuan Province, this study systematically analyzed disaster risk perception, sense of place, evacuation willingness, and relocation willingness among residents in these earthquake-stricken areas. Further, this study constructed an ordinal logistic regression analysis to probe the correlations between residents' disaster risk perception or sense of place and evacuation willingness and relocation willingness, respectively. The results showed that (1) faced with the threat of earthquake disasters, residents have a strong willingness to evacuate and relocate. Specifically, 93% and 78% of the residents in the Wenchuan Earthquake and Lushan Earthquake areas were willing to evacuate and relocate, respectively, whereas 4% and 17% of the residents were unwilling to evacuate and relocate, respectively. (2) Place dependence and the severity of disaster occurrence were significantly positively correlated with residents' evacuation willingness, while the interaction term between place dependence and the severity of disaster occurrence was negatively related to residents' evacuation willingness. Specifically, when everything else remains constant, every one-unit increase in place dependence and severity corresponds to increases in the odds of willingness to evacuate by factors of 0.042 and 0.051, respectively; every one-unit increase in place dependence × severity corresponds to a decrease in the odds of willingness to evacuation by a factor of 0.004. (3) Place identity was significantly negatively correlated with residents' relocation willingness, while place dependence and severity of disaster occurrence were positively related to residents' relocation willingness. The interaction term between place dependence and the severity of disaster occurrence as well as the interaction term between place identity and severity of disaster occurrence were significantly negatively correlated with residents' relocation willingness. Specifically, every one-unit increase in place identity corresponds to a decrease in the odds of willingness to relocate by a factor of 0.034, while every one-unit increase in place dependence and severity corresponds to increases in the odds of willingness to relocate by factors of 0.041 and 0.028, respectively, and every one-unit increase in place dependence × severity and place identity × severity corresponds to decreases in the odds of willingness to relocate by factors of 0.003 and 0.003, respectively.

4.
J Sep Sci ; 43(2): 496-504, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31671238

RESUMO

Hyperbranched polytriazine functionalized with humic acid was prepared and developed as new sorbents for dispersive solid-phase extraction of three acaricides (clofentezine, fenpyroximate, and pyridaben) in tea samples combined with high-performance liquid chromatography detection. The sorbents were characterized by scanning electron microscopy, energy dispersive spectroscopy, Zeta-potential, and Fourier transform infrared spectroscopy. The extraction parameters (extraction time, ionic strength, desorption conditions) were optimized. The adsorption mechanism was evaluated utilizing Fourier transform infrared spectra. Under optimum conditions, satisfactory analytical performances were achieved, which included high precision (1.33-9.62%), low limits of detection (0.19-3.54 µg/L), and wide linear range (2.5-500 µg/L) for the analysis of the acaricides. Moreover, the proposed method proved highly effective for the determination of acaricides in tea samples, with the relative recoveries in the range of 65.20-108.13% and relative standard deviations < 9.87%. The method has great application potential for the detection of acaricides in tea samples.

5.
J Inorg Biochem ; 201: 110820, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31518871

RESUMO

Seven Cu(II) complexes with 5-pyridin-2-yl-[1,3]dioxolo[4,5-g]isoquinoline derivatives as ligands: [Cu2(L1)2Cl4] (1), [Cu(L2)Cl2] (2), [Cu(L1)(NO3)2] (3), [Cu(L2)(NO3)2] (4), [Cu(L3)Cl2] (5), [Cu(L3)Br2] (6) and [Cu(L3)(NO3)2] (7){L1=9-nitro-5-pyridin-2-yl-[1,3]dioxolo[4,5-g]isoquinoline, L2=4-nitro-5-pyridin-2-yl-[1,3]dioxolo[4,5-g]isoquinoline, L3=9-bromo-5-pyridin-2-yl-[1,3]dioxolo[4,5-g]isoquinoline}, were synthesized and characterized. Their in vitro anticancer activities against T-24, MGC-80-3, HeLa, Hep-G2, A549 and SK-OV-3 were evaluated. Compared with their corresponding ligands, most of these complexes exhibited enhanced anticancer activities in contrast to their corresponding ligands and copper salt. Among them, complexes 1 and 3 displayed selective cytotoxicity to HeLa cells comparing with normal liver cell HL-7702, with IC50 values of 5.03 ±â€¯1.20 µM and 10.05 ±â€¯0.52 µM, respectively. Complexes 1 and 3 inhibited telomerase activity by interacting with c-myc promoter elements, and therefore exerted their antitumor activity. Furthermore, complexes 1 and 3 could trigger cell apoptosis via disruption of mitochondrial pathway through notably increased reactive oxygen species (ROS) levels, loss of mitochondrial membrane potential (Δψm), increase of the cytochrome c and apaf-1, decrease of bcl-2, and activation of caspases 3/9. Complexes 1 and 3 exhibited enhanced cytotoxicity, presenting synergetic effect after the ligands coordinated to copper(II) center.

6.
Artigo em Inglês | MEDLINE | ID: mdl-31514264

RESUMO

Sichuan is a province in Southwest China that is famous worldwide for its earthquakes. However, few quantitative studies in China have probed the correlations between rural households' financial preparation, disaster experience, and disaster-risk perception. Using survey data of 327 rural households from four areas stricken by the Wenchuan Earthquake and Lushan Earthquake in Sichuan, the ordinary least square (OLS) method was used to quantitatively explore the correlations between these three factors. The results show that rural households' total family cash income, asset diversity, and whether rural households can borrow money from relatives and friends whenever there is a catastrophe such as an earthquake are significantly negatively correlated with the probability of disaster occurrence. Asset diversity and whether rural households can borrow money from banks whenever there is a catastrophe such as an earthquake are significantly positively related to the severity of disaster occurrence. The severity of residents' disaster experience is not significantly correlated with the probability of disaster occurrence, but is significantly positively related to the severity of the disaster. The research results can provide useful enlightenment for the improvement of financial preparedness and disaster risk management for rural households in earthquake-stricken areas.


Assuntos
Planejamento em Desastres/economia , Terremotos/economia , Percepção , População Rural/estatística & dados numéricos , Adulto , Idoso , China , Planejamento em Desastres/estatística & dados numéricos , Desastres , Características da Família , Feminino , Humanos , Renda , Masculino , Pessoa de Meia-Idade , Modelos Estatísticos , Inquéritos e Questionários
7.
Molecules ; 24(15)2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31362458

RESUMO

As persistent organic pollutants, dichlorodiphenyltrichloroethanes (DDTs) and their metabolites pose considerable risks to human health and the environment. Therefore, monitoring DDTs in the environment is essential. Here, we developed a green, simple, and effective magnetic solid-phase extraction (MSPE) method coupled with gas chromatography tandem triple-quadrupole mass spectrometry to determine the DDT content of environmental water samples. A magnetic ionic liquid (IL) adsorbent was developed based on a modified magnetic multiwalled carbon nanotube/zeolitic imidazolate framework-8 (MM/ZIF-8/IL), synthesized by immobilizing the IL on the surface of MM/ZIF-8. We confirmed successful synthesis of MM/ZIF-8/IL by material characterization, and our results suggested that the MM/ZIF-8/IL had a high Brunauer-Emmett-Teller surface area (159.9 m2 g-1), good thermostability (<800 °C), and a high degree of superparamagnetism (52.9 emu g-1). Several experimental conditions affecting the MSPE efficiency were optimized. Under the best conditions, good detection linearity was achieved (0.5-500 µg L-1) with determination coefficients ranging from 0.9927 to 0.9971. The lower limits of detection (0.0016-0.0072 µg L-1) also had good precision, having an intraday relative standard deviation (RSD) ≤ 6.5% and an interday RSD ≤ 8.9%. Finally, we used the as-developed method to determine DDT levels in environmental water samples.


Assuntos
DDT/química , DDT/isolamento & purificação , Líquidos Iônicos , Magnetismo , Nanotubos de Carbono , Extração em Fase Sólida , Poluentes Químicos da Água , Nanotubos de Carbono/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Zeolitas/química
8.
Mikrochim Acta ; 186(6): 351, 2019 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-31093744

RESUMO

A magnetic sorbent was fabricated by covalently grafting hyperbranched polyamidoamine onto the surface of Fe3O4 nanoparticles. The sorbent was used in the magnetic solid-phase extraction (MSPE) of benzoylurea insecticides (BUs) from environmental water samples. It is perceived that hydrogen bonding interactions and hydrophobic interactions are the main mechanisms for the adsorption of BUs. The sorbent was characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, elemental analysis, Brunauer-Emmett-Teller measurement, X-ray photoelectron spectroscopy, vibrating sample magnetometry and X-ray diffraction. Various experimental parameters affecting the MSPE were optimized. Following elution with acetonitrile, the BUs were quantified by HPLC with diode array detection. The method based has a wide linear response range (2.5-500.0 ng mL-1), satisfactory coefficient of determination (0.9922-0.9976), high enrichment factors (62.8-74.4), acceptable limits of quantitation (2.5 ng mL-1) and low limits of detection (0.39-0.72 ng mL-1). The intra-day precision at concentration levels of 5.0, 50.0 and 250.0 ng mL-1 ranged from 2.3-6.4% and the inter-day precision was between 1.0 and 5.5%. The sorbent can be re-used at least 15 times. It was applied to the extraction of BUs from genuine water samples where it showed satisfactory relative recoveries (75.1-111.4%) and precision (1.0-9.1%). Graphical abstract Schematic presentation of magnetic nanoparticles modified with hyperbranched polyamidoamine and their application for extraction of benzoylurea insecticides.

9.
J Colloid Interface Sci ; 549: 42-49, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31015055

RESUMO

Herein, we have constructed NiFe-LDH nanoparticles modified ultrathin TiO2/BiVO4 nanosheet heterojunction arrays and explored the effects of different NiFe-LDH loading amount on photoelectrochemical water oxidation performance. The photocurrent of as-prepared TiO2/BiVO4/NiFe-LDH photoanode is about 2.5 times than that of TiO2/BiVO4, which is ascribed to the synergistic effect of heterojunction and co-catalyst. The heterojunction between TiO2 and BiVO4 suppresses the recombination of photogenerated electron-hole pairs effectively and the co-catalyst of NiFe-LDH accelerates the surface water oxidation reaction kinetics.

10.
J Colloid Interface Sci ; 546: 211-220, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30921675

RESUMO

Graphene oxide (GO) with oxygen containing functional groups can be selectively modified by small biomolecules to achieve heterogeneous surface properties. To achieve a hyper-enzymatic activity, the surface functionality of GO should be tailored to the orientation adsorption of the Thermomyces lanuginosus (TL) lipase, and the active center can be covered by a relatively hydrophobic helical lid for protection. In this work, amino acids were used to interact with GO through reduction reaction, hydrophobic forces, electrostatic forces, or hydrogen bonding to alter the surface hydrophobicity and charge density. Characterization of the structure and surface properties confirmed that the GO samples decorated with phenylalanine (Phe) and glutamic acid (Glu) exhibited superior hydrophobicity than other modifications, whereas tryptophan (Trp) and cysteine (Cys) provided weaker reduction effects on GO. Moreover, the zeta potential of the samples modified by amino acids of lysine (Lys) and arginine (Arg) is higher than other modified samples. The adsorption amount of lipase on Glu-GO reached 172 mg/g and the relative enzymatic activity reached up to 200%. The thermodynamic data and the Freundlich isotherm model fitting showed that the lipase adsorption process on modified samples was spontaneous, endothermic and entropy increase.


Assuntos
Aminoácidos/química , Ascomicetos/enzimologia , Grafite/química , Lipase/química , Adsorção , Lipase/metabolismo , Tamanho da Partícula , Propriedades de Superfície
11.
J Sep Sci ; 42(8): 1610-1619, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30770622

RESUMO

In this work, a method for the analysis of benzoylurea insecticides, including hexaflumuron, flufenoxuron, lufenuron and chlorfluazuron, in tea samples by high-performance liquid chromatography with Fe3 O4 -hyperbranched polyester nanocomposite as the adsorbent for magnetic solid-phase extraction was developed. The magnetic nanocomposite was prepared and characterized by infrared spectroscopy, vibrating sample magnetometry, and scanning electron microscopy. The as-prepared nanocomposite was used as a sorbent for the extraction and preconcentration of pesticide residues in tea samples. The extraction and desorption conditions, including mass ratios of raw materials, amount of sorbent, pH value, extraction time, and desorption time, were investigated. Under the final conditions chosen for the analysis, good linearity was obtained for all the tested compounds, with R2 values of at least 0.9979. The limits of detection were determined in the range of 0.15-0.3 µg/L. The recovery obtained from the analysis of tea samples with various spiked concentrations was between 90.7 and 98.4%, with relative standard deviations (n = 4) lower than 4.1%. Furthermore, the present approach was successfully applied to the quantitative determination of residues of benzoylurea insecticides in real samples.


Assuntos
Benzamidas/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Contaminação de Alimentos/análise , Inseticidas/isolamento & purificação , Compostos de Fenilureia/isolamento & purificação , Piridinas/isolamento & purificação , Extração em Fase Sólida/métodos , Chá/química , Adsorção , Benzamidas/análise , Inseticidas/análise , Magnetismo , Nanopartículas de Magnetita/química , Nanocompostos/química , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/isolamento & purificação , Compostos de Fenilureia/análise , Poliésteres/química , Piridinas/análise , Extração em Fase Sólida/instrumentação
12.
J Chromatogr A ; 1589: 10-17, 2019 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-30591248

RESUMO

In this study, four triazine herbicides-namely, simazine, ametryn, prometryn and terbuthylazine-were separated and determined using high-performance liquid chromatography coupled with ultraviolet detector (HPLC-UVD). The deep eutectic solvent (DES) formed by tetrabutylammonium chloride ([N4444]Cl, TBA) and ethylene glycol (EG) was selected as the extraction solvent of vortex-assisted reversed-phase liquid-liquid microextraction (VA-RPLLME). The application of the hydrophilic DES expands the range of choice for LLME. The experimental parameters affecting the extraction recoveries, including the amount of the DES, the sample volume and the vortex time, were investigated and optimized by the design of experiments (DoE) methodology. A quadratic model, namely central composite face-centered (CCF) design featuring 20 runs was used instead of the conventional trial and error approach. Under optimum conditions, the limits of determination (LODs) of the method were 0.60-1.50 µg L-1. The enrichment factors for the analytes ranged from 27 to 31. The extraction recoveries were in the range of 84.1-104.9%, and the intra-day, inter-day and intermediate relative standard deviations (RSDs) were less than 8.4%. Finally, the method was applied for the determination of triazine herbicides in vegetable oil samples. The obtained recoveries were in the range of 60.1-107.2% and RSDs were lower than 8.1%. In general, VA-RPLLME can be complementary to the present available methods for the determination of triazine herbicides in vegetable oil samples.


Assuntos
Cromatografia de Fase Reversa/métodos , Herbicidas/isolamento & purificação , Microextração em Fase Líquida/métodos , Óleos Vegetais/química , Plantas Comestíveis/química , Solventes/química , Triazinas/isolamento & purificação , Limite de Detecção , Reprodutibilidade dos Testes
13.
Food Chem ; 268: 485-491, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30064787

RESUMO

A novel dispersive magnetic solid phase microextraction method based on ionic liquid-coated and cyclodextrin-functionalized magnetic core dendrimer nanocomposites has been developed for the determination of pyrethroids in juice samples. The different generation magnetic core dendrimer nanocomposites were successfully synthesized and the nanocomposites possess both the selective retention of guest dendrimer and cyclodextrin molecules and high adsorption capacities of ionic liquids. The extraction efficiencies of different generation magnetic core dendrimer nanocomposites were compared, and the type of nanocomposite with the highest recovery was obtained. Under the optimized experimental conditions, the method showed good linearity in the range of 3.5-500 µg L-1. The LODs and LOQs were in the ranges of 0.36-1.3 µg L-1 and 1.2-4.3 µg L-1, respectively. The method also showed acceptable accuracies ranging from 98.2% to 99.4%. The proposed method was demonstrated to broaden the potential applications of dendrimer for the detection of pyrethroid residues in various juice samples.


Assuntos
Sucos de Frutas e Vegetais/análise , Líquidos Iônicos/química , Piretrinas/química , Microextração em Fase Sólida/métodos , Cromatografia Líquida de Alta Pressão , Ciclodextrinas , Dendrímeros/química , Nanocompostos , Piretrinas/isolamento & purificação
14.
Inorg Chem ; 57(14): 8673-8680, 2018 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-29953222

RESUMO

Biohazards and chemical hazards as well as radioactive hazards have always been a threat to human health. The search for solutions to these problems is an ongoing worldwide effort. In order to control biohazards by chemical methods, a synthetically useful fused tricyclic iodine-rich compound, 2,6-diiodo-3,5-dinitro-4,9-dihydrodipyrazolo [1,5- a:5',1'- d][1,3,5]triazine (5), with good detonation performance was synthesized, characterized, and its properties determined. This compound which acts as an agent defeat weapon has been shown to destroy certain microorganisms effectively by releasing iodine after undergoing decomposition or combustion. The small iodine residues remaining will not be deleterious to human life after 1 month.


Assuntos
Desinfetantes/farmacologia , Substâncias Explosivas/farmacologia , Iodo/química , Triazinas/farmacologia , Desinfetantes/síntese química , Desinfetantes/química , Escherichia coli/efeitos dos fármacos , Substâncias Explosivas/síntese química , Substâncias Explosivas/química , Calefação , Staphylococcus aureus/efeitos dos fármacos , Triazinas/síntese química , Triazinas/química
15.
Artigo em Inglês | MEDLINE | ID: mdl-29763746

RESUMO

In this study, a novel ionic liquid-type surfactant modified attapulgite named as 1-dodecyl-3-methylimidazolium bromide-attapulgite (C12MIM-ATP) is successfully prepared and applied in dispersive solid phase extraction (dSPE) for the fast determination of pyrethroid residues in tea drinks. The primary factors that influenced the extraction efficiency, including sorbent type, amount of sorbent, extraction time, desorption conditions, pH and ionic strength, are investigated. The optimized results reveal that the extraction and desorption equilibria are rapidly obtained within 1 min. Under the optimized conditions, good linearity (2-500 µg/L) is observed for four pyrethroids in tea drinks with determination coefficients (r2) ranged from 0.9992 to 1.0000. The limits of detection (LODs) are 0.6 µg/L for all pesticides. Acceptable extraction recoveries of target analytes are found from 90.28 to 107.56% with relative standard deviations (RSDs) less than 8.30% in real tea drink samples. The batch-to-bath repeatability is evaluated by recovery test on five independent synthesized C12MIM-ATP sorbents. Satisfactory batch-to-batch repeatability is obtained with the recovery factors varied in 15%. A small matrix effect is observed using C12MIM-ATP as the sorbent for detection pyrethroids in tea drinks.


Assuntos
Compostos de Magnésio/síntese química , Piretrinas/análise , Piretrinas/química , Compostos de Silício/síntese química , Extração em Fase Sólida/métodos , Tensoativos/química , Chá/química , Cromatografia Líquida de Alta Pressão/métodos , Líquidos Iônicos/química , Limite de Detecção , Microscopia Eletrônica de Varredura/métodos , Praguicidas/análise , Praguicidas/química , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Propriedades de Superfície , Termogravimetria/métodos
16.
J Chromatogr A ; 1559: 86-94, 2018 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-29685334

RESUMO

A novel membrane emulsification-assisted liquid-liquid microextraction method based on the solidification of floating organic drops was used to detect four pyrethroid pesticides (deltamethrin, etofenprox, fenpropathrin, and bifenthrin). In this method, [P44412]Br was used as a surfactant that could be removed from water via the addition of KPF6. The extraction solvent was separated after centrifugation and solidification on the water surface. The parameters affecting the recovery of the target compounds, including the surfactant amount, [P44412]Br-to-KPF6 molar ratio, addition of salt, extraction solvent volume, and temperature, were individually optimized and further analyzed through an orthogonal array design (OAD) experiment. The optimized conditions were based on the results of the OAD experiment and single-factor analysis. Using these experimental conditions, the recovery of the four pyrethroids ranged from 91.3% to 98.1% with relative standard deviation (RSD) values ranging from 1.7 to 2.2%. Good linearity was observed, with values from 0.9982 to 0.9997, and the linear range was between 1 and 500 µg/L (5-500 µg/L for fenpropathrin). The limit of detection (LOD) values based on a signal-to-noise ratio (S/N) of 3:1 were 0.37-0.75 µg/L. The enrichment factor ranged from 90 to 96. Therefore, this method is suitable for the determination of pyrethroid pesticides in environmental water samples.


Assuntos
Inseticidas/análise , Microextração em Fase Líquida/métodos , Piretrinas/análise , Cromatografia Líquida de Alta Pressão , Inseticidas/isolamento & purificação , Limite de Detecção , Nitrilos/análise , Nitrilos/isolamento & purificação , Piretrinas/isolamento & purificação , Razão Sinal-Ruído , Tensoativos/química , Temperatura Ambiente , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/isolamento & purificação
17.
Food Chem ; 239: 797-805, 2018 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-28873637

RESUMO

A green, simple, inexpensive, and sensitive ionic liquid immobilized fabric phase sorptive extraction method coupled with high performance liquid chromatography was developed for rapid screening and simultaneous determination of four fungicides (azoxystrobin, chlorothalonil, cyprodinil and trifloxystrobin) residues in tea infusions. This IL modified extraction fiber is capable of extracting target analytes directly from complicated tea water matrices with the addition of surfactant. A series of extraction conditions were investigated by one-factor-at-a-time approach and orthogonal test. After a series experiments, the optimum conditions were found to be 10% [HIMIM]NTf2 as coating solution, 2min vortex time, 500µL acetonitrile as dispersive solvent and 2min desorption time. Under the above conditions, the proposed technique was applied to detect fungicides from real tea water samples with satisfactory results.


Assuntos
Chá , Cromatografia Líquida de Alta Pressão , Fungicidas Industriais , Líquidos Iônicos , Microextração em Fase Líquida , Tensoativos , Poluentes Químicos da Água
18.
J Sep Sci ; 40(23): 4563-4570, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28960849

RESUMO

We present a novel dispersive liquid-liquid microextraction method based on the solidification of deep eutectic solvent coupled with high-performance liquid chromatography with a variable-wavelength detection for the detection of five benzoylureas in real water samples. In this work, a green solvent consisting of 1-octyl-3-methylimidazolium chloride and 1-dodecanol was used as an extraction solvent, yielding the advantages of material stability, low density, and a suitable freezing point near room temperature. Parameters that significantly affect extraction efficiency were optimized by the one-factor-at-a-time approach. Under optimal conditions, the recoveries of five target compounds were obtained ranging from 87.39 to 98.05% with correlation coefficients ranging from 0.9994 to 0.9997 for pure water. The limits of detection were in the range of 0.09-0.16 µg/L. The enrichment factors were in the range of 171-188. Linearities were achieved in the range of 0.5-500 µg/L. The proposed method was successfully applied to determine benzoylureas in environmental water samples with a satisfactory recovery of approximately 81.38-97.67%.

19.
J Chromatogr A ; 1516: 1-8, 2017 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-28818328

RESUMO

In the present study, a simple and rapid sample preparation method designated ultrasound-assisted dispersive liquid-liquid microextraction based on a deep eutectic solvent (DES) followed by high-performance liquid chromatography with ultraviolet (UV) detection (HPLC-UVD) was developed for the extraction and determination of UV filters from water samples. The model analytes were 2,4-dihydroxybenzophenone (BP-1), benzophenone (BP) and 2-hydroxy-4-methoxybenzophenone (BP-3). The hydrophobic DES was prepared by mixing trioctylmethylammonium chloride (TAC) and decanoic acid (DecA). Various influencing factors (selection of the extractant, amount of DES, ultrasound duration, salt addition, sample volume, sample pH, centrifuge rate and duration) on UV filter recovery were systematically investigated. Under optimal conditions, the proposed method provided good recoveries in the range of 90.2-103.5% and relative standard deviations (inter-day and intra-day precision, n=5) below 5.9%. The enrichment factors for the analytes ranged from 67 to 76. The limits of detection varied from 0.15 to 0.30ngmL-1, depending on the analytes. The linearities were between 0.5 and 500ngmL-1 for BP-1 and BP and between 1 and 500ngmL-1 for BP-3, with coefficients of determination greater than 0.99. Finally, the proposed method was applied to the determination of UV filters in swimming pool and river water samples, and acceptable relative recoveries ranging from 82.1 to 106.5% were obtained.


Assuntos
Cromatografia Líquida de Alta Pressão , Monitoramento Ambiental/métodos , Microextração em Fase Líquida , Água/química , Benzofenonas/análise , Limite de Detecção , Rios/química , Solventes/química , Ultrassonografia , Poluentes Químicos da Água/análise
20.
J Sep Sci ; 40(17): 3513-3521, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28675591

RESUMO

An ultrasound-assisted, hybrid ionic liquid, dispersive liquid-liquid microextraction method coupled to high-performance liquid chromatography with a variable-wavelength detector was developed to detect ten insecticides, including diflubenzuron, triflumuron, hexaflumuron, flufenoxuron, lufenuron, diafenthiuron, transfluthrin, fenpropathrin, γ-cyhalothrin and deltamethrin, in fruit juices. In this method, an appropriate extraction solvent was chosen based on the partition coefficient of the target compounds. A mixture of 1-octyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide and 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide was used as the extractant. The extraction efficiency was screened using Plackett-Burman design and optimized using central composite design. Under the optimal conditions, good linearity was obtained for all the analytes in the pure water model and the fruit juice samples. In pure water, the recoveries of the ten insecticides ranged from 85.7 to 108.9%, with relative standard deviations for one day ranging from 1.24 to 2.64%. The limits of detection were in the range of 0.19-0.69 µg/L, and the enrichment factors were in the range of 123-160. The logarithm of the n-octanol/water partition coefficient in this experiment is a useful reference to select a suitable extraction solvent, and the proposed technique was applied for the analysis of ten insecticides in fruit juice with satisfactory results.


Assuntos
Contaminação de Alimentos/análise , Sucos de Frutas e Vegetais/análise , Inseticidas/análise , Microextração em Fase Líquida , Cromatografia Líquida de Alta Pressão , Diflubenzuron/análise , Líquidos Iônicos , Ultrassom
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