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1.
Clin Pharmacol Drug Dev ; 13(2): 208-218, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-38185925

RESUMO

Tirbanibulin ointment 1% is approved in the United States and Europe for the treatment of actinic keratosis with demonstrated efficacy, safety, and tolerability when applied over a field up to 25 cm2 . This Phase 1 maximal-use trial determines the plasma pharmacokinetics, safety, and tolerability of tirbanibulin ointment 1% applied to 100 cm2 of the face or balding scalp in adults with actinic keratosis. Twenty-eight patients self-applied tirbanibulin once daily for a single 5-day treatment course. On Day 5, the mean maximum plasma concentration was 1.06 ng/mL and area under the plasma concentration-time curve during a dosing interval was 16.2 ng â€¢ h/mL. Systemic exposure was approximately 4-fold higher than in a previous pharmacokinetic study with a 25 cm2 field, consistent with the increase in the treated area. Tirbanibulin applied to a 100-cm2 treatment field showed favorable safety and tolerability. The most common treatment-emergent adverse events were application site reactions (in 35.7% of patients). All treatment-emergent adverse events and most of the tolerability signs were mild/moderate and resolved or returned to baseline by Day 29. In summary, under maximal-use conditions, tirbanibulin ointment 1% was safe and well tolerated supporting its potential use over a field up to 100 cm2 .


Assuntos
Acetamidas , Ceratose Actínica , Morfolinas , Piridinas , Adulto , Humanos , Ceratose Actínica/tratamento farmacológico , Ceratose Actínica/diagnóstico , Pomadas , Resultado do Tratamento , Europa (Continente)
2.
Food Chem ; 403: 134324, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36174342

RESUMO

The individual effects of iprovalicarb, mepanipyrim, and tetraconazole on the volatile composition and aromatic profile of Monastrell-based wines were evaluated. To date, no studies about the effect of these fungicides on Monastrell-based wines are available, and the effect on other grape varieties is also unknown. Fungicides were added separately in the cellar to the grape must at two concentration levels (4 and 10 mg/kg for iprovalicarb and mepanipyrim and 1 and 2.5 mg/kg for tetraconazole). The aromatic composition of the final wines was analysed by gas chromatography using flame ionisation and ion trap mass selective detectors. In the presence of fungicides, the most significant variations were observed for isoamyl acetate and 2-phenylethyl acetate (increasing between 20 and 43% compared with the control wine) and ethyl caprate and caprylate (increasing between 12 and 68%). Consequently, treated wines showed a higher global odourant intensity, with increased fresh fruit notes.


Assuntos
Fungicidas Industriais , Vitis , Compostos Orgânicos Voláteis , Vinho , Vinho/análise , Fungicidas Industriais/análise , Vitis/química , Odorantes/análise , Compostos Orgânicos Voláteis/análise
3.
Molecules ; 26(21)2021 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-34771074

RESUMO

The Mediterranean diet includes virgin olive oil (VOO) as the main fat and olives as snacks. In addition to providing nutritional and organoleptic properties, VOO and the fruits (olives) contain an extensive number of bioactive compounds, mainly phenolic compounds, which are considered to be powerful antioxidants. Furthermore, olive byproducts, such as olive leaves, olive pomace, and olive mill wastewater, considered also as rich sources of phenolic compounds, are now valorized due to being mainly applied in the pharmaceutical and nutraceutical industries. The digestive system must physically and chemically break down these ingested olive-related products to release their phenolic compounds, which will be further metabolized to be used by the human organism. The first purpose of this review is to provide an overview of the current status of in-vitro static digestion models for olive-related products. In this sense, the in-vitro gastrointestinal digestion methods are widely used with the following aims: (i) to study how phenolic compounds are released from their matrices and to identify structural changes of phenolic compounds after the digestion of olive fruits and oils and (ii) to support the functional value of olive leaves and byproducts generated in the olive industry by assessing their health properties before and after the gastrointestinal process. The second purpose of this review is to survey and discuss all the results available to date.


Assuntos
Modelos Biológicos , Olea/química , Azeite de Oliva/química , Fenóis/metabolismo , Olea/metabolismo , Azeite de Oliva/metabolismo , Fenóis/química
4.
Food Microbiol ; 92: 103554, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32950148

RESUMO

The effect of two commercial formulations (incorporating mepanipyrim and tetraconazole as active substances) on the metabolism of Saccharomyces cerevisiae Lalvin T73™, growing on a synthetic grape must, and their influence on the alcoholic fermentation course and the biosynthesis of volatiles derived from phenylalanine catabolism was studied. No relevant effects were observed for mepanipyrim except for glycerol production. On the contrary, in the presence of tetraconazole many genes and some proteins related to cell cycle progression and mitosis were repressed. This fact could explain the lower biomass concentration and the lower sugar consumption registered for tetraconazole at the end of the study. However, the biomass-to-ethanol yield was higher in connection with the overexpression of the ADH1 gene. The presence of tetraconazole residues seems to accelerate the Ehrlich pathway. These results agree with the overexpression of several genes (BAT1, PDC1, PDC5, ADH1, SFA1, ATF2, PFK1, PFK2 and ARO3) and a higher abundance of two proteins (Gap1p and Atf2p) involved in this metabolic pathway.


Assuntos
Antifúngicos/farmacologia , Fenilalanina/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo , Biomassa , Clorobenzenos/farmacologia , Etanol/metabolismo , Fermentação/efeitos dos fármacos , Redes e Vias Metabólicas/efeitos dos fármacos , Pirimidinas/farmacologia , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Triazóis/farmacologia
5.
J Proteomics ; 227: 103915, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32711165

RESUMO

This work aimed to evaluate the modifications on the proteome profile of Saccharomyces cerevisiae T73™ strain as a consequence of its adaptive response to the presence of tetraconazole molecules in the fermentation medium. Pasteurised grape juices were separately supplemented with tetraconazole or a commercial formulation containing 12.5% w/v of tetraconazole at two concentration levels. In addition, experiments without fungicides were developed for comparative purposes. Proteome profiles of yeasts cultured in the presence or absence of fungicide molecules were different. Independently of the fungicide treatment applied, the highest variations concerning the control sample were observed for those proteins involved in metabolic processes, especially in the metabolism of nitrogen compounds. Tetraconazole molecules altered the abundance of several enzymes involved in the biosynthesis of amino acids, purines, and ergosterol. Moreover, differences in the abundance of several enzymes of the TCA cycle were found. Changes observed were different between the active substance and the commercial formulation. SIGNIFICANCE: The presence of fungicide residues in grape juice has direct implications on the development of the aromatic profile of the wine. These alterations could be related to changes in the secondary metabolism of yeasts. However, the molecular mechanisms involved in the response of yeasts to fungicide residues remains quite unexplored. Through this exhaustive proteomic study, alterations in the amino acids biosynthesis pathways due to the presence of the tetraconazole molecules were observed. Amino acids are precursors of some important higher alcohols and ethyl acetates (such as methionol, 2-phenylethanol, isoamyl alcohol or 2-phenylacetate). Besides, the effect of tetraconazole on the ergosterol biosynthesis pathway could be related to a higher production of medium-chain fatty acids and their corresponding ethyl acetates.


Assuntos
Saccharomyces cerevisiae , Vinho , Clorobenzenos , Fermentação , Proteoma , Proteômica , Triazóis , Vinho/análise
6.
Food Chem ; 300: 125223, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31362157

RESUMO

The impact of fungicides mepanipyrim (Mep) and tetraconazole (Tetra) and their corresponding commercial formulations (Mep-Form and Tetra-Form) on the aroma composition of wines was assessed. Fungicide residues can affect the biotransformation of aroma precursors from grapes and/or the yeast metabolism. The results confirmed that both maximum residue levels (MRL and 2xMRL) of Mep promoted benzyl alcohol and 4-vinylguaiacol contents; while MRL and 2xMRL of Mep-Form promoted benzene derivatives (benzyl alcohol, benzaldehyde, and trans-isoeugenol), 2-phenylethanol and γ-nonalactone. The addition of Tetra (2xMRL) and Tetra-Form (MRL and 2xMRL) release higher contents of cis-3-hexen-1-ol and ethyl vanillate and affected yeast metabolism related to phenylacetaldehyde, 2-phenylethanol, methionol, capric acid, ethyl 2-methylbutyrate, ethyl isovalerate, ethyl monosuccionate, diethyl succinate and γ-butyrolactone production. Fungicide residues did not display higher variations in global odour activity values with respect to control wines, although some variations on the "floral", "fruity", "spicy" and "lactic" nuances could be sensed.


Assuntos
Clorobenzenos/farmacologia , Pirimidinas/farmacologia , Triazóis/farmacologia , Vitis/efeitos dos fármacos , Compostos Orgânicos Voláteis/metabolismo , Vinho , Fermentação , Contaminação de Alimentos/análise , Frutas/química , Frutas/efeitos dos fármacos , Frutas/metabolismo , Fungicidas Industriais , Odorantes/análise , Vitis/química , Vitis/metabolismo , Compostos Orgânicos Voláteis/análise , Vinho/análise , Vinho/microbiologia , Leveduras/efeitos dos fármacos , Leveduras/metabolismo
7.
Int J Mol Sci ; 20(6)2019 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-30909373

RESUMO

The effect of fungicides on fermentation is of paramount importance to control the quality and safety of wines. In this work, the quality (enological parameters, color, phenolic content, antioxidant activity, and fungicide residues) of wines from Monastrell grapes fortified with iprovalicarb, mepanipyrim, and tetraconazole fungicides was evaluated. Along the winemaking process, initial residues of mepanipyrim and tetraconazole were removed in more than 90% while the dissipation of iprovalicarb was around 73%. Significant statistical differences were found in the presence of iprovalicarb and mepanipyrim residues, especially at the highest concentration assayed. For both fungicides, increases in the volatile acidity (between 4 and 8.6 times), the lactic acid content (between 8.6 and 20.5 times), the percentage of polymeric anthocyanins (between 1.3 and 1.7 times), and also a slight increase of the total phenolic index and the total anthocyanin content determined by spectrophotometry were observed. On the contrary, the total monomeric anthocyanins content decreased about 16.3% and 28.6% in the presence of iprovalicarb and mepanipyrim, respectively. These results could be related to a higher development of acetic acid or lactic bacteria in the presence of these fungicides. The color of the final wines was also different in comparison with the control, with a higher yellow component, color intensity, tonality, and hue angle because of pH changes in the medium. Tetraconazole fermentations had a more similar trend to the control wine, probably due to the lower concentration of this fungicide in the grape must at the initial time. No effects on the antioxidant activity was observed for any of the target fungicides. A multivariate statistical analysis was done to view the interrelationships between different variables (color and anthocyanins profile). The obtained model allowed the wines to be separated according to the fungicide treatment applied.


Assuntos
Antocianinas/análise , Fungicidas Industriais/farmacologia , Pigmentação , Vitis/química , Vitis/efeitos dos fármacos , Vinho/análise , Antioxidantes/análise , Antioxidantes/química , Cor , Fermentação
8.
Food Res Int ; 108: 339-346, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29735065

RESUMO

Five photodegradation products of metrafenone (MTF) and six of mepanipyrim (MEP) were identified in synthetic grape juice at 25 °C and the structures of the main reaction products established. The degradation of MTF and MEP was modelled by using three different strategies involving monitoring (a) the disappearance of the parent compound, (b) the conversion of the parent compound into its main structurally related reaction products and (c) the degradation of the parent compound to all intermediates and degradation end-products. The kinetic coefficients of degradation for these fungicides were determined and the corresponding half-lives found to be 20.8 h for MFT and 10.1 h for MEP. The proposed models afford reasonably accurate interpretation of the experimental data. Based on the results, modelling the kinetics of disappearance of the parent compound by itself does not ensure the best fit of the degradation behaviour of the fungicides.


Assuntos
Benzofenonas/análise , Análise de Alimentos/métodos , Sucos de Frutas e Vegetais/análise , Fungicidas Industriais/análise , Pirimidinas/análise , Vitis , Benzofenonas/efeitos da radiação , Fungicidas Industriais/efeitos da radiação , Concentração de Íons de Hidrogênio , Hidrólise , Cinética , Modelos Teóricos , Fotólise , Pirimidinas/efeitos da radiação , Temperatura
9.
Water Res ; 102: 561-571, 2016 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-27423406

RESUMO

The aim of this study was to propose kinetic models suitable for reproducing and predicting mancozeb (Mz) conversion to by-products as a function of the operational conditions. The main factors (pH, temperature and light) potentially affecting the mancozeb degradation in aqueous models were studied by a multifactorial screening design. In addition, the response surface methodology (RSM) was applied to evaluate the interactive effects of these factors on ethylenethiourea (ETU) formation. The response surface revealed that the best degradation conditions to minimize mancozeb conversion to ETU were low pH (2), low temperature (25 °C) and darkness. Under these conditions, the percentage of mancozeb remained in the solution at 72 h was approximately 10% of the initial concentration and the percentage of ETU conversion was 5.4%. However, according to the model, in surface waters under typical environmental conditions (pH 8, 25 °C and light) the percentage of mancozeb conversion to ETU would be about 17.5%. The proposed model provides a satisfactory interpretation of the experimental data obtained during the hydrolysis of mancozeb.


Assuntos
Etilenotioureia , Fotólise , Fungicidas Industriais , Hidrólise , Água
10.
Anal Bioanal Chem ; 407(23): 7101-10, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26215168

RESUMO

The aim of this work is the development of a simple, fast, quantitative, and economic method for the determination of neonicotinoid insecticide residues in dietary bee pollen. Several parameters of the method, such as extraction solvent, extraction time, and solid-phase extraction sorbents for purification [silica, C18, primary-secondary amine (PSA), and Envi-Carb II/PSA], were studied. The final proposed method based on solid-liquid extraction with hexane, cleanup with Supelclean™ Envi-Carb II/PSA cartridges, and subsequent analysis by high-performance liquid chromatography with tandem mass spectrometry was validated and applied to the analysis of commercial bee pollen samples from different geographical zones. Method performance was assessed by the evaluation of several quality parameters of the method, such as recovery values, repeatability, reproducibility, linearity, and limits of detection and quantification. Matrix effects on the chromatographic signal were also studied. The quality parameters of the method were equivalent to or better than those obtained with previously published methods, with recoveries between 81 and 99% and repeatabilities lower than 8.8%. The detection and quantification limits were in the ranges 0.2-2.2 µg kg(-1) and 0.4-4.3 µg kg(-1), respectively.


Assuntos
Abelhas/química , Contaminação de Alimentos/análise , Inseticidas/análise , Resíduos de Praguicidas/análise , Pólen/química , Espectrometria de Massas em Tandem/métodos , Anabasina/análise , Animais , Cromatografia Líquida de Alta Pressão/métodos , Análise de Alimentos/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
11.
Crit Rev Food Sci Nutr ; 55(8): 1053-73, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-24915355

RESUMO

Dessert sweet wines from Europe and North America are described in this review from two points of view: both their aroma profile and also their sensorial description. There are growing literature data about the chemical composition and sensory properties of these wines. Wines were grouped according to the production method (concentration of sugars in grapes) and to the aging process of wine (oxidative, biological, or a combination of both and aging in the bottle). It was found that wines natively sweets and wines fortified with liquors differ in their volatile compounds. Sensory properties of these wines include those of dried fruit (raisins), red berries, honey, chocolate and vanilla, which is contributing to their growing sales. However, there is still a need for scientific research on the understanding of the mechanisms for wine flavor enhancement.


Assuntos
Carboidratos/análise , Frutas/química , Vitis , Compostos Orgânicos Voláteis/análise , Vinho/análise , Botrytis/metabolismo , Fermentação , Manipulação de Alimentos/métodos , Olfato , Paladar , Fatores de Tempo , Vinho/microbiologia
12.
Crit Rev Food Sci Nutr ; 55(6): 839-63, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-24915365

RESUMO

Residues of pesticides in food are influenced by processing such as fermentation. Reviewing the extensive literature showed that in most cases, this step leads to large reductions in original residue levels in the fermented food, with the formation of new pesticide by-products. The behavior of residues in fermentation can be rationalized in terms of the physical-chemical properties of the pesticide and the nature of the process. In addition, the presence of pesticides decrease the growth rate of fermentative microbiota (yeasts and bacterias), which provokes stuck and sluggish fermentations. These changes have in consequence repercussions on several aspects of food sensory quality (physical-chemical properties, polyphenolic content, and aromatic profile) of fermented food. The main aim of this review is to deal with all these topics to propose challenging needs in science-based quality management of pesticides residues in food.


Assuntos
Fermentação , Análise de Alimentos , Contaminação de Alimentos , Qualidade dos Alimentos , Resíduos de Praguicidas/análise , Biotransformação , Manipulação de Alimentos , Humanos
13.
Crit Rev Food Sci Nutr ; 55(2): 202-18, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-24915400

RESUMO

Volatile organic compounds are vital to wine quality, determining their aroma and varietal characteristics. Which are present, and in what quantity, depends on the cultivar, the situation and soil of the vineyard, weather, cultivation methods, and wine-making practices. Here, we review the literature on the development of wine aroma compounds in grapes, and how it is affected by the above-named factors. Increasing understanding of these processes at the molecular level will aid vine growers in the optimal selection of harvest dates and other decisions favoring the consistent production of balanced, flavorful berries.


Assuntos
Frutas/química , Vitis/química , Compostos Orgânicos Voláteis/análise , Vinho/análise , Agricultura/métodos , Manipulação de Alimentos/métodos , Frutas/crescimento & desenvolvimento , Efeito Estufa , Odorantes/análise , Solo/química , Vitis/crescimento & desenvolvimento , Tempo (Meteorologia)
14.
Molecules ; 19(6): 8093-111, 2014 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-24936710

RESUMO

The effect of two anti-fungal treatments (metrafenone and boscalid + kresoxim-methyl) on the color and phenolic profile of Tempranillo and Graciano red wines has been studied. To evaluate possible modifications in color and phenolic composition of wines, control and wines elaborated with treated grapes under good agricultural practices were analyzed. Color was assessed by Glories and CIELab parameters. Color changes were observed for treated wines with boscalid + kresoxim-methyl, leading to the production of wines with less color vividness. Phenolic profile was characterized by HPLC analysis. Boscalid + kresoxim-methyl treatment promoted the greatest decrease on the phenolic content in wines.


Assuntos
Antifúngicos/farmacologia , Benzofenonas/farmacologia , Compostos de Bifenilo/farmacologia , Niacinamida/análogos & derivados , Fenilacetatos/farmacologia , Vinho/análise , Cromatografia Líquida de Alta Pressão , Metacrilatos/farmacologia , Niacinamida/farmacologia , Fenóis/análise , Estrobilurinas , Vitis/química , Vitis/efeitos dos fármacos
15.
Environ Sci Pollut Res Int ; 18(7): 1139-46, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21336633

RESUMO

PURPOSE: Solid waste incineration has recently attracted much attention because the combustion process involved produces highly toxic organohalogen contaminants such as dioxin-like polychlorinated biphenyls (DL-PCBs) present in fly ash. This has raised the need for simple, rapid, accurate methods for monitoring PCBs in ash samples. METHODS: A method for the simultaneous quantitative determination of indicator, non-ortho and mono-ortho PCBs based on ultrasound-assisted extraction with 50:50 (v/v) n-hexane/acetone was developed, validated, and subsequently applied to real samples from a mussel shell incinerator facility in Galicia. The overall method quantification limits range from 0.35 to 1.5 ng/g in fly ash waste, from 0.30 to 1.0 ng/g in bottom ashes, and from 1.0 to 2.0 ng/g in sludge samples. Mean recoveries between 70% and 105% are achieved. RESULTS: DL-PCBs were identified in ash and in sludge samples collected from the wastewater treatment plant of the waste incineration facility. The enrichment factors for fly ash ranged from 3.3 to 3.7. Sewage sludge was also found to contain some polychlorinated biphenyls such as PCB 77 (29 ± 5.0 ng/g; n=4) and PCB 169 (6.9 ± 0.89 ng/g; n=4), as well as three of the seven PCB-like indicators, namely: PCB 138 (14 ± 4.4 ng/g), PCB 153 (6.1 ± 1.4 ng/g), and PCB 180 (7.7 ± 3.0 ng/g). Toxicity equivalent concentrations were 0.0054 ng/g for bottom ash, 0.0264 ng/g for fly ash, and 3.6 ng/g for sewage sludge; these values are well below the limit for DL-PCBs in wastes recently set by the European Union. CONCLUSIONS: All samples studied contained PCBs at levels below the maximum tolerated limit established by European legislation. Based on their PCB content, the studied sewage sludge can be used as a soil amendment with no health risk. Also, fly ash and sewage sludge can be deemed stable PCB reservoirs releasing PCBs at concentrations below the regulatory cutoff to runoff water.


Assuntos
Poluentes Atmosféricos/análise , Bivalves/química , Carbono/análise , Monitoramento Ambiental/métodos , Incineração , Material Particulado/análise , Bifenilos Policlorados/análise , Poluentes Atmosféricos/química , Poluentes Atmosféricos/toxicidade , Animais , Bivalves/metabolismo , Carbono/química , Carbono/toxicidade , Cinza de Carvão , Material Particulado/química , Material Particulado/toxicidade , Bifenilos Policlorados/química , Bifenilos Policlorados/toxicidade , Esgotos/análise , Esgotos/química , Volatilização
16.
Anal Bioanal Chem ; 396(6): 2265-72, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20135307

RESUMO

A rapid, robust and economical method for the analysis of persistent halogenated organic compounds in small volumes of human serum and umbilical cord blood is described. The pollutants studied cover a broad range of molecules of contemporary epidemiological and legislative concern, including polychlorobiphenyls (PCBs), polychlorobenzenes (CBs), hexachlorocyclohexanes (HCHs), DDTs, polychlorostyrenes (PCSs) and polybromodiphenyl ethers (PBDEs). Extraction and clean-up with n-hexane and concentrated sulphuric acid was followed with analysis by gas chromatography coupled to electron capture (GC-ECD) and GC coupled to negative ion chemical ionisation mass spectrometry (GC-NICI-MS). The advantages of this method rest in the broad range of analytes and its simplicity and robustness, while the use of concentrated sulphuric acid extraction/clean-up destroys viruses that may be present in the samples. Small volumes of reference serum between 50 and 1000 microL were extracted and the limits of detection/quantification and repeatability were determined. Recoveries of spiked compounds for the extraction of small volumes (> or = 300 microL) of the spiked reference serum were between 90% and 120%. The coefficients of variation of repeatability ranged from 0.1-14%, depending on the compound. Samples of 4-year-old serum and umbilical cord blood (n = 73 and 40, respectively) from a population inhabiting a village near a chloro-alkali plant were screened for the above-mentioned halogenated pollutants using this method and the results are briefly described.


Assuntos
Cromatografia Gasosa/métodos , Poluentes Ambientais/sangue , Sangue Fetal/química , Hidrocarbonetos Halogenados/sangue , Soro/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Pré-Escolar , Poluentes Ambientais/química , Feminino , Humanos , Hidrocarbonetos Halogenados/química , Limite de Detecção , Masculino
17.
J Agric Food Chem ; 57(7): 2843-8, 2009 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-19334759

RESUMO

The objective of this work was to assess the sorption of copper (Cu) applied as a Cu-oxychloride metalaxyl formulation by soils characterized by anthropogenic accumulation of Cu due to agricultural activity. The methods involved batch incubation of soils with a Cu-oxychloride metalaxy-based fungicide suspended in 0.01 M CaCl(2), phase separation, and determination of the concentration of Cu (Cu) in solution. Results showed that specific soil properties influenced solubilization of the Cu from the fungicide. The amount of dissolved Cu depended on the soil pH, its potential acidity, and its cation exchange capacity. The amount of anthropogenic Cu in the soil had a minor influence on soluble Cu after the addition of the fungicide. Thus, Cu-based antifungal treatment can increase the local concentration of soluble Cu in acid soils but is not likely to affect the [Cu] in moderately acidic or neutral soils.


Assuntos
Cobre/química , Fungicidas Industriais/química , Solo/análise , Adsorção , Cobre/análise , Concentração de Íons de Hidrogênio , Solubilidade
18.
J Colloid Interface Sci ; 333(2): 431-8, 2009 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-19268966

RESUMO

Herbicide soil/solution distribution coefficients (K(d)) are used in mathematical models to predict the movement of herbicides in soil and groundwater. Herbicides bind to various soil constituents to differing degrees. The universal soil colloid that binds most herbicides is organic matter; however metallic hydrous oxides might also have some influence. The adsorption-desorption of three quaternary ammonium herbicides on soils with different chemical-physical characteristics was determined using a batch equilibration method before and after the following sequential selective dissolution procedures: removal of organic matter, and removal of organic matter plus free iron oxides. The experimentation involved paraquat (PQ), diquat (DQ) and difenzoquat (DFQ) herbicides. The distribution coefficients (K(d)) of the molecules and their correlation to the soil components were determined and a significant negative correlation with organic carbon was highlighted (r<-0.610, p<0.035, n=12). All quats cations experiment high adsorption in the control soils with a Zeta potential at about -21 mV. The order of adsorption on soils (based on K(d)) was the following: PQ>DQ>>DFQ. The adsorption isotherms of these three herbicides on the natural and processed soils were satisfactorily fitted with the Freundlich equation, and a significant correlation with organic carbon was highlighted for quats K(F) (r<-0.696, p<0.012, n=12). The removal of organic matter from soils seems to leave free new adsorption sites for quats on the clay surface, which is no longer occluded by organic matter. This work shows that the amount and nature of the surface that remains available after the removal of single soil constituents is a critical parameter in determining the sorptive behavior of cationic contaminants.


Assuntos
Ácido Cítrico/química , Compostos Férricos/química , Herbicidas/química , Solo/análise , Adsorção , Silicatos de Alumínio/análise , Argila , Diquat/química , Diquat/isolamento & purificação , Ditionita/química , Herbicidas/isolamento & purificação , Peróxido de Hidrogênio/química , Paraquat/química , Paraquat/isolamento & purificação , Pirazóis/química , Pirazóis/isolamento & purificação
19.
Anal Bioanal Chem ; 394(6): 1535-44, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19194695

RESUMO

Foliar runoff is one of the most important processes affecting off-target movement of fungicides. In this way, Ridomil Gold Plus and Ridomil Gold MZ are two types of wettable powder technical formulations which contain metalaxyl and they are used for such a purpose. A method for quantitative determination of metalaxyl in pesticide formulas has been developed, validated, and subsequently applied to Ridomil Gold Plus and Ridomil Gold MZ. The method employs liquid-liquid extraction followed by liquid chromatography coupled with UV detection (LC-UV), using gas chromatography coupled with mass spectrometry as confirmation technique and to carry out a screening of organic adjuvants of these two selected pesticide formulas. Metalaxyl of 26.5 and 41 g/kg was detected in Ridomil Gold Plus and Ridomil Gold MZ, close to the manufacture specified level of 25 and 40 g/kg, respectively. Activator and utility adjuvants were detected in these two wettable powder technical formulations. Only methyl-ester-based surfactants were found within the group of nonionic surfactants, but the long-term fates of most adjuvants in soils and elsewhere in the environment are largely unknown, partially because of the lack of long-term monitoring data.


Assuntos
Adjuvantes Farmacêuticos/análise , Alanina/análogos & derivados , Química Farmacêutica/métodos , Praguicidas/química , Adjuvantes Farmacêuticos/classificação , Alanina/análise , Cromatografia Líquida , Cromatografia Gasosa-Espectrometria de Massas , Concentração de Íons de Hidrogênio , Fenômenos de Química Orgânica , Pós , Solventes , Espectrofotometria Ultravioleta , Molhabilidade
20.
Pest Manag Sci ; 65(6): 615-23, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19165728

RESUMO

BACKGROUND: Flow shear stress induced by rainfall promotes the loss of the pesticides sprayed on crops. Some of the factors influencing the losses of colloidal-size particulate fungicides are quantified by using a rotating shear system model. With this device it was possible to analyse the flow shear influencing washoff of a commercial fungicide formulation based on a copper oxychloride-metalaxyl mixture that was sprayed on a polypropylene surface. A factor plan with four variables, i.e. water speed and volume (both variables determining flow boundary stress in the shear device), formulation dosage and drying temperature, was set up to monitor colloid detachment. RESULTS: This experimental design, together with sorption experiments of metalaxyl on copper oxychloride, and the study of the dynamics of metalaxyl and copper oxychloride washoff, made it possible to prove that metalaxyl washoff from a polypropylene surface is controlled by transport in solution, whereas that of copper oxychloride occurs by particle detachment and transport of particles. Average losses for metalaxyl and copper oxychloride were, respectively, 29 and 50% of the quantity applied at the usual recommended dosage for crops. CONCLUSION: The key factors affecting losses were flow shear and the applied dosage. Empirical models using these factors provided good estimates of the percentage of fungicide loss. From the factor analysis, the main mechanism for metalaxyl loss induced by a shallow water flow is solubilisation, whereas copper loss is controlled by erosion of copper oxychloride particles.


Assuntos
Alanina/análogos & derivados , Cobre/química , Fungicidas Industriais/química , Água/química , Adsorção , Alanina/química , Coloides/química , Cinética , Solubilidade , Temperatura
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