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1.
Mater Sci Eng C Mater Biol Appl ; 128: 112333, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474884

RESUMO

Polyetheretherketone (PEEK) was widely applied into fabricating of orthopaedic implants, benefitting its excellent biocompatibility and similar mechanical properties to native bones. However, the inertness of PEEK hinders its integration with the surrounding bone tissue. Here PEEK scaffolds with a series of hydroxyapatite (HA) contents in gradient were manufactured via fused filament fabrication (FFF) 3D printing techniques. The influence of the pore size, HA content and printing direction on the mechanical properties of the PEEK/HA scaffolds was systematically evaluated. By adjusting the pore size and HA contents, the elastic modulus of the PEEK/HA scaffolds can be widely tuned in the range of 624.7-50.6 MPa, similar to the variation range of natural cancellous bone. Meanwhile, the scaffolds exhibited higher Young's modulus and lower compressive strength along Z printing direction. The mapping relationship among geometric parameters, HA content, printing direction and mechanical properties was established, which gave more accurate predictions and controllability of the modulus and strength of scaffolds. The PEEK/HA scaffolds with the micro-structured surface could promote cell attachment and mineralization in vitro. Therefore, the FFF-printed PEEK/HA composites scaffolds can be a good candidate for bone grafting and tissue engineering.


Assuntos
Durapatita , Cetonas , Benzofenonas , Polietilenoglicóis , Polímeros , Porosidade , Impressão Tridimensional , Tecidos Suporte
2.
Ecotoxicol Environ Saf ; 222: 112534, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34311429

RESUMO

Penflufen fungicide is widely used as a racemate, which has potential ecological risks to aquatic organisms, while its enantioselective toxicity data is limited. This study aimed to differentiate the enantioselective toxicity difference of penflufen enantiomers, and illuminate the enantioselective mechanism from the insight of enantiomer-protein specific binding. The semipreparative separation and absolute configuration of penflufen enantiomers were conducted. The acute toxicity of S-(+)-penflufen was 54 times higher than R-(-)-penflufen to Danio rerio, and the coexistence of R-(-)-penflufen could increase the exposure risk of S-(+)-penflufen. For chronic toxicity, after low-dose long-term exposure, rac-penflufen and S-(+)-penflufen inducted more serious oxidative stress than R-(-)-penflufen in D. rerio, and inhibited the succinate dehydrogenase (SDH) activity significantly. For target phytopathogen, the toxicity difference of S-(+)-penflufen and R-(-)-penflufen was up to 148 times for Rhizoctonia solani. Based on the toxic unit analysis, the toxic interactions of antagonistic effect and concentration addition were found between penflufen enantiomers, indicating the coexistence of R-(-)-penflufen could increase overuse and environmental risks. Computational chemistry was used to illuminate the enantioselectivity mechanism, and the lower binding energy between the active site of SDH and S-(+)-penflufen contributed to the higher toxicity. The higher target toxicity might be due to the hydrophobic pocket of CybL in R. solani was more benefited to S-(+)-penflufen binding SDH than Botrytis cinerea. These results could be helpful for further understanding the potential risk of chiral penflufen in the environment, demonstrating the importance of understanding the enantioselective difference of chiral pesticides, and providing a new insight for analyzing the enantioselective mechanism.


Assuntos
Fungicidas Industriais , Anilidas , Botrytis , Química Computacional , Fungicidas Industriais/toxicidade , Rhizoctonia , Estereoisomerismo
3.
Food Chem ; 346: 128920, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33387836

RESUMO

A high-throughput method using a new ZIF-8@GO thin-film microextraction coating was established for determining macrolides and lincosamides in honey. The coating preparation parameters (ZIF-8@GO synthesis conditions, coating material proportions, dipping time) and analysis parameters (sample diluent solvent, adsorption and desorption conditions using the ZIF-8@GO coating) were optimized. The optimized parameters were: diluent solvent sodium carbonate/sodium bicarbonate buffer solution (pH 9), adsorption time 45 min, desorption time 5 min, desorption solvent 45:40:15 v/v/v methanol/acetonitrile/water. The extracted targets were determined by ultra-high performance liquid chromatography tandem mass spectrometry. The recoveries of 10 analytes were 67.5-107.2% and the detection and quantification limits were 0.1-0.4 and 0.4-1.4 µg/kg, respectively. The method could analyze 96 samples per run. The minimal manual time and effort is required since the bulk of the sample processing is fully automated. It was a useful and efficient method for monitoring drug residues and was successfully used to analyze real samples.


Assuntos
Antibacterianos/análise , Mel/análise , Lincosamidas/análise , Microextração em Fase Líquida/métodos , Macrolídeos/análise , Acetonitrilas , Cromatografia Líquida de Alta Pressão/métodos , Limite de Detecção , Espectrometria de Massas em Tandem/métodos
4.
Food Chem ; 343: 128490, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33158673

RESUMO

Dendrobium officinale Kimura et Migo (D. officinale) is a dual-use plant with both botanical medicine and food applications, drawing increasing attentions. Pesticides are inevitably applied on D. officinale in commercial artificial-sheltered cultivation, yet little is known about pesticide residue levels in D. officinale. A modified high through-put QuEChERS method coupled with HPLC-MS/MS was developed and validated to detect 76 pesticides in D. officinale. Graphitized multi-wall carbon nanotubes (g-MWCNTs) was selected as the clean-up sorbent, showing relative weak affinity to triazole fungicide having planar structure in their molecular and low matrix effects of pesticides in D. officinale samples compared to MWCNTs and pesticarb. The validated method was applied to analyze pesticide residues in 86 real D. officinale samples collected from three main producing provinces. 43 different pesticides were detected with highest residue of 6.11 mg/kg for dimethomorph. Given possible health risks related to pesticide residues, accordingly, risk assessment of human exposure to pesticides via intake of D. officinale was thus performed, indicating that the pesticide residue in fresh or dry D. officinale would not cause potential risk to human health either in the long-term or short-term. This work improved our understanding of potential exposure risk of pesticide multi-residues in D. officinale.


Assuntos
Dendrobium/química , Exposição Dietética/análise , Análise de Alimentos/métodos , Resíduos de Praguicidas/análise , Contaminação de Alimentos/análise , Humanos , Nanotubos de Carbono/química , Medição de Risco
5.
Environ Pollut ; 269: 116191, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33316505

RESUMO

Co-occurrence of pesticides and heavy metals has attracted extensive attention. The enantioselective behaviors of dinotefuran to aquatic organisms have not been reported, and the effects of cadmium (Cd) was absent, which were investigated in this study at environmentally relevant concentrations. The enantioselective accumulation and elimination of dinotefuran enantiomers were observed in zebrafish, and it had tissue specificity. The S-dinotefuran concentrations were higher than R-dinotefuran in heads and viscera, but it was opposite in muscles. There existed competition between S-dinotefuran and R-dinotefuran, and the existence of S-dinotefuran might decrease the accumulation and elimination of the R-dinotefuran in zebrafish. When co-exposure to Cd and dinotefuran, the accumulation concentrations of dinotefuran enantiomers increased in zebrafish at the initial stage, which were opposite latterly. The accumulation concentrations of R-dinotefuran in R + Cd treatment in fish were 3.4 times higher than those in R-dinotefuran treatment, and the enantiomer fraction (EF) values changed from 0.484 to 0.195. The oxidative stress of S-dinotefuran on zebrafish was highest, followed by rac- and R-dinotefuran. Co-exposure to Cd led to toxicity increase for R-dinotefuran, the malonaldehyde (MDA) content decreased significantly in R + Cd treatment during 7-28 days, while obvious declination of MDA contents was found on the 28th day in R-dinotefuran treatment. Furthermore, compared to R-dinotefuran treatment, Cd increased the relative expression of cz-sod (3.4 times), cas3 (1.6 times) and p53 (5.7 times) in R + Cd treatment. The co-exposure of Cd might alter the environmental behaviors and toxicity effects of dinotefuran enantiomers in zebrafish, including the enantioselectivity. The effects of Cd on accumulation and toxicity of R-dinotefuran were greater than those on S-dinotefuran. Thus, it is necessary to consider the effects of coexistent metals to chiral pesticides in ecological risk. SUMMARIZES: The enantioselective accumulation and elimination of dinotefuran enantiomers had tissue specificity. Cd increased the accumulation and toxicity of R-dinotefuran in zebrafish.


Assuntos
Poluentes Químicos da Água , Peixe-Zebra , Animais , Bioacumulação , Cádmio/toxicidade , Guanidinas , Neonicotinoides , Nitrocompostos , Estereoisomerismo , Poluentes Químicos da Água/toxicidade
6.
Sci Total Environ ; 758: 144067, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33321360

RESUMO

Repeated spraying of fungicides is a common phenomenon in greenhouse strawberry cultivation, and the continuous harvest of strawberries makes them prone to contamination by accumulated fungicides. Despite this, very few residue safety assessments of fungicides on greenhouse strawberries are conducted after repeated spraying of fungicides, and no research exists on fungicide dissipation and accumulation mechanism. Therefore, the present study investigated the dissipation and accumulation of four fungicides (pyraclostrobin, pyrimethanil, procymidone, and cyprodinil) after two typical repeated sprayings (a single fungicide repeated spraying and two fungicides sprayed using an alternate repeated technique). The half-life of pyraclostrobin after three single repeated sprayings was 18 d; however, its average half-life decreased to 9 d after alternate repeated spraying with cyprodinil. The shortened half-life may be attributed to cyprodinil water solution washing during alternate repeated spraying. The other three fungicides showed similar half-lives after single and alternate repeated spraying, following the order of cyprodinil (12 d and 10 d) > procymidone (11 d and 10 d) > pyrimethanil (6 d and 7 d). The octanol-water partition coefficient was a more efficient indicator of the half-life order of the fungicides than vapor pressure and water solubility. Pyraclostrobin showed the highest deposition efficiency but negligible residue accumulation; further, the residue accumulation of the four fungicides followed the order of procymidone > cyprodinil > pyrimethanil > pyraclostrobin after both single and alternate repeated spraying. A safety assessment demonstrated that the maximum number of times cyprodinil could be sprayed after single spraying was one; however, this number doubled after alternate spraying. The risk of exceeding the maximum residue limits of the fungicides on greenhouse strawberries decreased; however, the combined dietary risks of fungicides after alternate spraying might be high. Alternate repeated spraying of procymidone and pyrimethanil may be the optimal repeated spraying combination for greenhouse strawberries.


Assuntos
Fragaria , Fungicidas Industriais , Resíduos de Praguicidas , Fungicidas Industriais/análise , Resíduos de Praguicidas/análise , Medição de Risco
7.
Food Chem ; 338: 128074, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32950011

RESUMO

A separation and analysis method of fosthiazate stereoisomers was established utilizing supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS) with a CHIRALPAK AD-3 column. The determination of the four fosthiazate stereoisomers could be completed within 6 min. The environmental behaviors of fosthiazate stereoisomers were studied in legume vegetables. After applying fosthiazate granules to soil, the concentrations of fosthiazate stereoisomers in the legume vegetables increased with time, reached maximum values in 7-10 days, and then decreased gradually in all legumes except for in Glycine max. No obvious dissipation behaviors were observed in Glycine max. Interestingly, the stereoselective behaviors were species-specific. A-(-), B-(-) and B-(±)-fosthiazate were preferentially enriched in Phaseolus vulgaris Linn and Vigna unguiculata, while A-(+) and A-(±)-fosthiazate preferentially accumulated in Vicia faba Linn, Pisum sativum Linn and G. max. The opposite stereoselectivity of B-(±)-fosthiazate was observed in different growth stage of G. max. No stereoselective dissipation occurred in soil.


Assuntos
Fabaceae/química , Compostos Organofosforados/química , Espectrometria de Massas em Tandem/métodos , Tiazolidinas/química , Cromatografia com Fluido Supercrítico , Fabaceae/metabolismo , Ervilhas/química , Ervilhas/metabolismo , Phaseolus/química , Phaseolus/metabolismo , Soja/química , Soja/metabolismo , Estereoisomerismo , Vicia faba/química , Vicia faba/metabolismo
8.
J Chromatogr A ; 1627: 461387, 2020 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823095

RESUMO

A simple and efficient magnetic solid-phase extraction (MSPE) method was established with magnetic covalent organic framework (COF) as adsorbent to enrich organophosphorus pesticides from fatty milk samples, followed by the sensitive determination via LC-MS/MS. The key parameters influencing the MSPE efficiency were comprehensively investigated to afford an optimized procedure. All the target analytes could be captured directly by magnetic COF from milk without protein precipitation, making the pretreatment rapid and convenient. Systematic method validation demonstrated its satisfactory linearity, recoveries (80.0-105 %), and precision (RSDs <12.3 %). The method limits of quantification were 0.2-0.5 µg L-1. A comparison experiment to the reported solid-phase extraction fully verified the present MSPE more rapid, accurate, and environment-friendly. Furthermore, FT-IR and XPS analysis were performed to reveal the adsorption mechanisms of magnetic COF to organophosphorus pesticides, which could offer guidance on the rational design of COF adsorbent for various target analytes.


Assuntos
Fenômenos Magnéticos , Estruturas Metalorgânicas/química , Leite/química , Compostos Organofosforados/análise , Praguicidas/análise , Extração em Fase Sólida/métodos , Acetonitrilas/análise , Adsorção , Animais , Limite de Detecção , Espectroscopia Fotoeletrônica , Padrões de Referência , Reprodutibilidade dos Testes , Solventes/química , Espectroscopia de Infravermelho com Transformada de Fourier
9.
Mater Sci Eng C Mater Biol Appl ; 116: 111249, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32806287

RESUMO

Osteogenic and angiogenic properties are two most valued factors for bone grafting materials. Biomedical materials with synergistic promotion effects on these two properties would be highly desirable. In this study, we showed that a recently developed pH-neutral bioactive glass (PSC) possessed such characteristics. Compared to two classical biomaterials, 45S5 bioactive glass and beta-tricalcium phosphate (ß-TCP), PSC markedly improved BMSCs' proliferation, migration and mineralization as well as their osteogenic and angiogenic differentiation. In vivo, PSC showed better performance on inducing bone regeneration than both 45S5 and ß-TCP, as featured by elevated bone mineral density (BMD) and new bone areas. PSC also significantly promoted new blood vessels formation compared with those in control groups. Furthermore, we revealed that PSC induced osteogenic and angiogenic differentiation of BMSCs through the PI3K/Akt/HIF-1α pathway, which had not been reported before. This synergistic effect of the PI3K/Akt/HIF-1α pathway on osteogenesis and angiogenic differentiation of BMSCs suggested that biomedical materials may promote new bone formation through multiple signal pathways, thus shedding light on the future development of materials with better performance.


Assuntos
Transplante Ósseo , Fosfatidilinositol 3-Quinases , Regeneração Óssea , Diferenciação Celular , Vidro , Concentração de Íons de Hidrogênio , Osteogênese
10.
Chemosphere ; 253: 126698, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32302901

RESUMO

Organophosphates insecticides (OPs) are one of the major environmental pollutants and their interaction with human serum albumin (HSA) has been shown to have significant effects on their bioavailability which is related to toxicokinetics and toxicodynamics in human body. In this research, solid-phase microextraction methods were developed to analyse the free concentrations of three OPs (chlorpyrifos, parathion-methyl and malathion) in buffered HSA solution and that provide a useful method for the determination of binding affinity constants (Ka), binding forces and binding location. Polydimethylsiloxane fibers were selected for analysing the free concentrations of OPs, with an external calibration approach. Good linearities conducted in PBS solution were observed in the range of 0.0025-1.7 µmol L-1 (R2 = 0.9975) for chlorpyrifos, 1.0-27 µmol L-1 (R2 = 0.9974) for parathion-methyl, and 0.5-70 µmol L-1 (R2 = 0.9973)for malathion, respectively. The LODs for instrument response were 1 ng, 5 ng and 10 ng for chlorpyrifos, parathion-methyl and malathion, respectively. The Ka values for chlorpyrifos, parathion-methyl and malathion showed that they were positively correlated with hydrophobicity and negatively correlated with temperature. The OP binding sites on HSA were confirmed by site marker competition test and further proven by computational approaches. The recognition region of parathion-methyl was situated within residues 199-292 in subdomain IIA. Malathion bonded to residues 404-558 in subdomain IIIA. The mode of action between HSA-parathion-methyl and HSA-malathion is found to involve mainly by H-bonds, π-π stacking and hydrophobic effects. These results clearly demonstrate the noncovalent binding of OPs with HSA and provide new insight into solid-phase microextraction, thermodynamics and computational approaches.


Assuntos
Inseticidas/toxicidade , Compostos Organofosforados/toxicidade , Clorpirifos , Dimetilpolisiloxanos , Humanos , Inseticidas/química , Inseticidas/metabolismo , Malation/análise , Metil Paration , Compostos Organofosforados/química , Compostos Organofosforados/metabolismo , Albumina Sérica Humana/química , Albumina Sérica Humana/metabolismo , Microextração em Fase Sólida , Temperatura , Termodinâmica
11.
Spectrochim Acta A Mol Biomol Spectrosc ; 235: 118266, 2020 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-32217441

RESUMO

In this work, a smart analytical strategy that combines excitation-emission matrix (EEM) fluorescence detection with alternating trilinear decomposition (ATLD) algorithm was developed for fast, on-line and interference-free study on the photodegradation kinetics of aflatoxin B1 (AFB1) and aflatoxin G1 (AFG1) in rice and wheat under UV-Vis light (λ = 250-500 nm) treatment. With the aid of prominent "second-order advantage" of ATLD method, pure fluorescence signals of two targeted analytes can be directly resolved out from heavily overlapping spectral environment and accurately quantified even in the presence of unknown matrix interferences. Cereal samples in kinetic processing of photodegradation were detected without complex pretreatment steps except for a simple extraction using methanol/water solution (4:1, v/v), which solves the problem facing varied matrix interferences in the case of on-line monitoring of aflatoxins. The kinetic signals of analytes of interest were directly extracted regardless of varied matrix backgrounds of various cereals. The kinetic curves and degradation speeds of AFB1 and AFG1 can be estimated by resolved quantitative data, optimal radiation conditions including 365 nm wavelength and 35 J m-2 density were discussed for high-efficiency detoxification control of aflatoxins in rice and wheat. This strategy was promising to be as an alternative tool for eco-friendly photodegradation kinetic study of mycotoxins or other hazards in complex foodstuff matrixes.


Assuntos
Aflatoxinas/análise , Contaminação de Alimentos/análise , Espectrometria de Fluorescência , Algoritmos , Calibragem , Cromatografia Líquida de Alta Pressão , Grão Comestível , Fluorescência , Cinética , Metanol/química , Modelos Teóricos , Oryza/química , Fotólise , Software , Triticum/química , Água/química
12.
J Sep Sci ; 43(8): 1558-1565, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32074394

RESUMO

A high-throughput and environmentally friendly method based on 96-well plate thin-film microextraction was established to determine 14 fungicides in grapes and grape juice using liquid chromatography-tandem mass spectrometry. The thin-film microextraction optimized method consisted of 60 min of extraction at pH 6.0 with the addition of sodium chloride (2-5%). Acetonitrile/water in the ratio of 8:2 was used for desorption analytes for 60 min. Evaluation of different extractive phases showed that polyacrylonitrile-polystyrene-divinylbenzene was the optimum coating. The linearity of the method was good in the range of 0.01-0.5 µg/mL for 14 fungicides with determination coefficients (R2 ) from 0.990 to 0.999, which indicated good linearity for both the grape juice and grape matrixes. The limit of detection was in the range of 0.002-0.01 µg/mL. The limit of quantitation was in the range of 0.01 mg/kg according to the minimum fortified level. The average absolute recoveries of the 14 fungicides ranged from 75.0 to 118.3%. The intraday relative standard deviation (n = 4) and interday relative standard deviation (n = 4) were 5.6-13.0% and 1.6-6.4%, respectively. This study showed that this method can be used for analyzing 96 samples in parallel, and the sample preparation time was approximately 2.0 min per sample. In addition, this approach offers a green and low-cost sample pretreatment technique for future analyses.


Assuntos
Sucos de Frutas e Vegetais/análise , Fungicidas Industriais/análise , Ensaios de Triagem em Larga Escala , Microextração em Fase Líquida , Vitis/química , Cromatografia Líquida , Espectrometria de Massas em Tandem
13.
Anal Chim Acta ; 1101: 65-73, 2020 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-32029120

RESUMO

A facile strategy was developed for the fabrication of a magnetic covalent organic framework (COF) via grafting of the monomers, 2,5-dihydroxyterephthalaldehyde (Dt) and 1,3,5-tris(4-aminophenyl) benzene (Tb) onto surface-modified Fe3O4 nanoparticles. The magnetic COF, named as magnetic COF-DtTb, was readily fabricated without high temperature or harsh reaction conditions. The synthesized magnetic COF-DtTb nanoparticles were fully characterized, presenting a regular core-shell spherical structure, large specific surface area, superparamagnetism, and good thermal stability. Their potential as an enrichment adsorbent was investigated to establish an efficient magnetic solid-phase extraction method for the determination of organophosphorus pesticide residues in fruits. Systematic method validation revealed good linearity in the concentration range of 1-200 µg L-1 (correlation coefficient >0.9957). The method limits of detection were in the range of 0.002-0.063 µg kg-1, the method limit of quantification was 1.00 µg kg-1 and recoveries ranged from 72.8% to 111% with RSDs lower than 12.3%. The results indicated that magnetic COF-DtTb possesses superior trace enrichment properties for organophosphorus pesticides in fruits.


Assuntos
Cumafos/isolamento & purificação , Frutas/química , Nanopartículas de Magnetita/química , Estruturas Metalorgânicas/química , Resíduos de Praguicidas/isolamento & purificação , Fosmet/isolamento & purificação , Adsorção , Cromatografia Líquida , Cumafos/análise , Cumafos/química , Limite de Detecção , Compostos Organotiofosforados/análise , Compostos Organotiofosforados/química , Compostos Organotiofosforados/isolamento & purificação , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/química , Fosmet/análise , Fosmet/química , Extração em Fase Sólida/métodos , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem
14.
Sci Total Environ ; 706: 136039, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31846872

RESUMO

Cis-epoxiconazole is a widely used triazole fungicide for control and prevention of a series of fungal diseases in fruits, vegetables, teas and grains. The present work aimed at exploring enantioselective behavior of cis-epoxiconazole in the vegetable-soil-earthworm system. Firstly, the absolute configuration of cis-epoxiconazole enantiomers was ascertained. Secondly, enantioselective degradation of cis-epoxiconazole in cabbage, pakchoi and pepper were performed under field trials, which has not been previously reported. Enantioselective degradation occurred in cabbage and pepper samples. 2R, 3S-(+)-cis-epoxiconazole was degraded faster than 2S, 3R-(-)-cis-epoxiconazole in cabbage, while the reversed results were obtained in pepper. No enantioselective degradation was observed in pakchoi. Finally, soil is the principal reservoir of environmental pesticides, so the enantioselective behaviors of cis-epoxiconazole in soil and soil organism (earthworm, Eisenia fetida) were evaluated. Similar bioaccumulation curves in earthworms and degradation curves in soil were observed under the exposure levels of 1 and 10 mg/kg. Accumulation factors (AFs) indicated earthworms had weak bioaccumulation potential to cis-epoxiconazole in the contaminated soil, and no obvious enantioselectivity was observed. The different enantioselectivities in different vegetables illuminated that preferentially enriched enantiomer might impose higher risk on human health than the other one, and the high risk enantiomer required further assessment. These results may reduce the uncertainty of cis-epoxiconazole to the environmental risk assessment.


Assuntos
Oligoquetos , Animais , Cromatografia Líquida , Compostos de Epóxi , Fungicidas Industriais , Espectrometria de Massas , Solo , Poluentes do Solo , Estereoisomerismo , Triazóis , Verduras
15.
Sci Total Environ ; 708: 135221, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31806340

RESUMO

To achieve multi-pesticides residue analysis in seawater, hydrophilic-lipophilic-balanced magnetic particles were designed and fabricated by swelling polymerization of divinyl benzene (DVB) and N-vinyl pyrrolidone (NVP) on the surface of Fe3O4@SiO2 magnetic particles. The ratio of DVB to NVP was adjusted to achieve a proper balance in hydrophilicity and lipophilicity. The obtained magnetic particles were systematically characterized by TEM, SEM, FT-IR and vibrating sample magnetization. Based on the optimized magnetic nanoparticles, a sensitive magnetic solid-phase extraction method was developed for the simultaneous pre-concentration and determination of 96-pesticide residues from large-volume seawater samples prior to being detected by liquid chromatography-tandem mass spectrometry. Recoveries of pesticides in spiked seawater samples (0.001, 0.01, 0.1, 1.0 µg L-1) ranged from 62% to 112% with RSDs less than 21%. The method limits of detection of 96 pesticides ranged from 0.13 to 0.42 ng L-1, the method limits of quantification of 96 pesticides ranged from 1.0 to 10 ng L-1. The method was successfully applied to pesticide residue analysis in water samples from Jiulong River Estuary of China, demonstrating the prospects of this technique as a potential method for the rapid determination of trace levels of multi-pesticide residues in seawater.

16.
Se Pu ; 38(12): 1396-1401, 2020 Dec 08.
Artigo em Chinês | MEDLINE | ID: mdl-34213254

RESUMO

Streptomycin (STR) and dihydrostreptomycin (DSTR) are two of the most common aminoglycoside antibiotics used in veterinary medicine. STR is produced by some streptomyces griseus strains, and DSTR is a derivative of STR. In recent years, STR has been widely used in grapes to induce denuclearization. However, high levels of STR may have adverse effects like serious ototoxicity and nephrotoxicity. Therefore, to ensure the quality of grapes and the health of consumers, the regulation of STR and DSTR levels in grapes is required. An analytical method was developed for the identification and quantification of STR and DSTR in grapes by liquid chromatography-tandem mass spectrometry (LC-MS/MS). STR and DSTR are highly polar compounds due to the presence of various amino and hydroxyl groups in their structure. The determination of STR and DSTR poses a considerable analytical challenge, both during sample preparation and instrument analysis. In this study, the main factors governing the response, recovery, and sensitivity of these compounds, such as the type of chromatographic column, the type and proportion of the mobile phase and extraction solvent, the dosage of sodium 1-hexane sulfonate solution, and elution solvent and its volume, were investigated during sample pretreatment and instrument analysis. The STR and DSTR residues in the grape sample were extracted by ultrasonication with a phosphoric acid solution (pH 2), and cleanup and enrichment was performed using an Oasis HLB solid phase column. The analysis was performed using a UPLC Waters HSS T3 column (100 mm×2.1 mm, 1.8 µm) at the column temperature of 35℃. The injection volume was 2 µL. The mobile phase consisted of 0.1% formic acid aqueous solution and methanol with a volume ratio of 60:40. ESI-MS/MS was operated in multiple reaction monitoring (MRM) mode. External standard calibration curves were used for quantification. Based on the optimized method, both analytes displayed good linearity between 2 and 400 µg/L. The correlation coefficients were 0.9991-0.9997. Recoveries in spiked blank grape samples (5, 10, 20, and 40 µg/kg) ranged from 76.8% to 91.9%, with the relative standard deviations (RSDs) less than 10.2%, in compliance with the current legislation. The limits of detection and the limits of quantification of both analytes were 1 µg/L and 5 µg/kg, respectively. To assess the feasibility and potential of the proposed approach for routine analyses of STR and DSTR in other kinds of grape samples, the developed method was applied to the analysis of these compounds in red grapes, xinyu grapes, and xiahei grapes. The recoveries of STR and DSTR in the three kinds of blank grape samples were 77.2%-83.9% and 70.8%-78.9%, respectively, and the RSDs ranged from 3.0% to 15.6%. The results showed that the optimized methods can yield satisfactory recoveries for the analytes in grapes. In this method, the combination of Waters HSS T3 column to overcome the difficulties of the retention and separation of these highly polar compounds in the reverse phase, avoids the use of an ion-pair additive in the mobile phase to increase their retention, which is known to cause severe contamination of the column and serious ion suppression with electrospray ionization detection. In addition, the ideal enrichment and purification effect can be achieved by adding a sodium 1-hexane sulfonate solution to the superstratum extract with the use of only Oasis HLB for sample treatment. The method described herein has the advantages of easy operation, accuracy, and selectivity, making it feasible for the identification and quantification of STR and DSTR residues in grapes.


Assuntos
Sulfato de Di-Hidroestreptomicina/análise , Resíduos de Drogas/análise , Frutas/química , Estreptomicina/análise , Vitis/química , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Análise de Alimentos , Contaminação de Alimentos , Extração em Fase Sólida , Espectrometria de Massas em Tandem
17.
Environ Monit Assess ; 191(11): 644, 2019 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-31606848

RESUMO

The bayberry is an important economic fruit as well as a minor crop in China, and few pesticide products are registered for bayberry. Prochloraz is a widely used fungicide with a high detection rate on bayberry. This study evaluated the potential dietary risk of prochloraz for different populations in China based on field trial data and market surveillance. The results indicate that one-time applications at dosages of 1000 and 1500 mg/kg with a recommended preharvest interval of 20 days do not pose a chronic or acute dietary risk. However, applying the above dosages twice will cause a potential short-term dietary risk. Risk assessment results conducted on surveillance samples indicated acceptable long-term risks for the general population, with a hazard quotient < 0.82. Furthermore, simulated washing and wine production processes were performed to mimic household practices to investigate residue transfer and distribution. We found that rinsing with tap water for 1 min was an effective way to remove residue, and the processing factors of prochloraz for both bayberry and wine were < 1, indicating that wine production could reduce residue levels. Prochloraz had a strong capacity to transfer to wine due to its high log Kow value, with transfer percentages up to 43%. This study supports the recommendation on good agricultural practices for prochloraz application and provides a guide for safe consumption.


Assuntos
Exposição Dietética/análise , Frutas/química , Fungicidas Industriais/análise , Imidazóis/análise , Myrica/química , Resíduos de Praguicidas/análise , Vinho/análise , China , Dieta , Medição de Risco
18.
J Sep Sci ; 42(18): 2968-2976, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31273899

RESUMO

A high-throughput method based on ultrasonic-assisted extraction, 96-well plate thin-film microextraction was established to determinate 18 antibiotics in animal feed. In this method, the extraction was implemented by ultrasonic-assisted extraction for 30 min with disodium ethylenediaminetetraacetic acid-McIlvaine buffer (pH 5) containing 6% sodium chloride w/v, purified by thin-film microextraction and combined with 96-well plate system to improve the efficiency. Optimization of thin-film microextraction conditions was performed by methods of single factor and response surface, and finalized as: condition time: 20 min; adsorption time: 55 min; washing time: 5 s with water; desorption time: 30 min with acetonitrile/water (8:2, v/v) containing 0.1% formic acid v/v. Evaluation of different extractive phases showed that polystyrene-divinylbenzene-polyacrylonitrile was the optimum coating. The analysis was performed by ultra-high performance liquid chromatography with tandem mass spectrometry. Recovery, inter- and intraday precision, linearity, limit of detection, and quantitation were evaluated. The average recoveries of 18 antibiotics were 66.6-93.5% at three spiked levels, intraday precision was 1-8.4%, and interday precision was 3.0-16.4%. The linearity was good for r2  > 0.99. Limits of detection and quantification were found in the range of 1-14 and 4-48 µg/kg, respectively.


Assuntos
Ração Animal/análise , Antibacterianos/análise , Ensaios de Triagem em Larga Escala , Microextração em Fase Líquida , Animais , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas em Tandem
19.
J Biomed Nanotechnol ; 15(3): 581-592, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31165702

RESUMO

Significant progress in artificial bone grafts has been achieved in recent years. However, none of them has osteogenic ability that is close to autogenous bones. Hence, improving osteogenic ability of artificial bone is the most prominent and challenging task in this field. In addition, angiogenesis could provide a stable environment and nutrients for survival of the cells and also plays a crucial role to the success of bone transplantation. In the present study, we combined citrate polymer and bioactive glass together as hybrids at the molecular level (PEC-GS/BG), with the expectation of acquiring osteogenic ability and angiogenic ability to repair bone defect that could comparable to autogenous bones. In vitro and in vivo experiment on the femoral condyle critical defects model of Sprague-Dawley rats were conducted for a complete evaluation. In vivo, the bone mineral density (BMD) in defects was no significant difference between autogenous bone groups (517 ± 21 mg/cm³) and PEC-GS/BG groups (509 ± 21 mg/cm³) (p > 0 05) at 12 weeks post-surgery. The BMD of the femoral condyle in normal males at the same age was measured to be 557 ± 16 mg/cm³, only slightly higher than the above date, indicating a nearly complete repair of the defects. It was also found that PEC-GS/BG promoted angiogenesis due to it stimulated organism to release vascular endothecial growth factor (VEGF). PEC-GS/BG also showed great osteogenic ability that was close to autogeneous bones, but much better angiogenic ability. What's more, from both protein and cell levels, PEC-GS/BG accelerated differentiation and mineralization of MC3T3E-1 cells. Consequently, osteogenetic performance of PEC-GS/BG was almost same to autogenous bones in repairing bone defects. Considering the high demand in bone grafts and all the difficulties in autogeneous bone supply, the PEC-GS/BG hybrids developed in this study may open a new horizon for bone repair.


Assuntos
Regeneração Óssea , Vidro , Animais , Masculino , Ratos , Ratos Sprague-Dawley
20.
Int J Mol Sci ; 20(5)2019 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-30841619

RESUMO

The auxin-like compound 2,4-dichlorophenoxyacetic acid (2,4-D) has been widely used as a plant growth regulator in cucumber fruit production; however, its influence on fruit development and metabolism has not been evaluated. In this study, the phenotype of cucumber fruits in both 2,4-D treatment and non-treatment control groups were recorded, and the metabolome of different segments of cucumber fruit at various sampling time points were profiled by a standardized non-targeted metabolomics method based on UPLC-qTOF-MS. The application of 2,4-D increased the early growth rate of the fruit length but had no significant effect on the final fruit length, and produced cucumber fruits with fresh flowers at the top. The 2,4-D treatment also affected the cucumber fruit metabolome, causing significant changes in the stylar end at 4 days after flowering (DAF). The significantly changed metabolites were mainly involved in methionine metabolism, the citric acid cycle and flavonoid metabolism pathways. At the harvest stage, 2,4⁻D treatment significantly decreased the levels of flavonoids and cinnamic acid derivatives while increased the levels of some of the amino acids. In summary, exogenous application of 2,4-D can greatly alter the phenotype and metabolism of cucumber fruit. These findings will assist in exploring the mechanisms of how 2,4-D treatment changes the fruit phenotype and evaluating the influence of 2,4-D treatment on the nutritional qualities of cucumber fruit.


Assuntos
Ácido 2,4-Diclorofenoxiacético/farmacologia , Cucumis sativus/efeitos dos fármacos , Reguladores de Crescimento de Plantas/farmacologia , Cucumis sativus/crescimento & desenvolvimento , Cucumis sativus/metabolismo , Frutas/efeitos dos fármacos , Metaboloma/efeitos dos fármacos
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