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1.
Molecules ; 26(21)2021 Nov 03.
Artículo en Inglés | MEDLINE | ID: mdl-34771074

RESUMEN

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.


Asunto(s)
Modelos Biológicos , Olea/química , Aceite de Oliva/química , Fenoles/metabolismo , Olea/metabolismo , Aceite de Oliva/metabolismo , Fenoles/química
2.
Food Microbiol ; 92: 103554, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32950148

RESUMEN

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.


Asunto(s)
Antifúngicos/farmacología , Fenilalanina/metabolismo , Saccharomyces cerevisiae/efectos de los fármacos , Saccharomyces cerevisiae/metabolismo , Biomasa , Clorobencenos/farmacología , Etanol/metabolismo , Fermentación/efectos de los fármacos , Redes y Vías Metabólicas/efectos de los fármacos , Pirimidinas/farmacología , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crecimiento & desarrollo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Triazoles/farmacología
3.
Int J Mol Sci ; 20(6)2019 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-30909373

RESUMEN

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.


Asunto(s)
Antocianinas/análisis , Fungicidas Industriales/farmacología , Pigmentación , Vitis/química , Vitis/efectos de los fármacos , Vino/análisis , Antioxidantes/análisis , Antioxidantes/química , Color , Fermentación
4.
Crit Rev Food Sci Nutr ; 55(2): 202-18, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-24915400

RESUMEN

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.


Asunto(s)
Frutas/química , Vitis/química , Compuestos Orgánicos Volátiles/análisis , Vino/análisis , Agricultura/métodos , Manipulación de Alimentos/métodos , Frutas/crecimiento & desarrollo , Efecto Invernadero , Odorantes/análisis , Suelo/química , Vitis/crecimiento & desarrollo , Tiempo (Meteorología)
5.
Crit Rev Food Sci Nutr ; 55(8): 1053-73, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-24915355

RESUMEN

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.


Asunto(s)
Carbohidratos/análisis , Frutas/química , Vitis , Compuestos Orgánicos Volátiles/análisis , Vino/análisis , Botrytis/metabolismo , Fermentación , Manipulación de Alimentos/métodos , Olfato , Gusto , Factores de Tiempo , Vino/microbiología
6.
Crit Rev Food Sci Nutr ; 55(6): 839-63, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-24915365

RESUMEN

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.


Asunto(s)
Fermentación , Análisis de los Alimentos , Contaminación de Alimentos , Calidad de los Alimentos , Residuos de Plaguicidas/análisis , Biotransformación , Manipulación de Alimentos , Humanos
7.
Anal Bioanal Chem ; 407(23): 7101-10, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26215168

RESUMEN

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.


Asunto(s)
Abejas/química , Contaminación de Alimentos/análisis , Insecticidas/análisis , Residuos de Plaguicidas/análisis , Polen/química , Espectrometría de Masas en Tándem/métodos , Anabasina/análisis , Animales , Cromatografía Líquida de Alta Presión/métodos , Análisis de los Alimentos/métodos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
8.
Molecules ; 19(6): 8093-111, 2014 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-24936710

RESUMEN

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.


Asunto(s)
Antifúngicos/farmacología , Benzofenonas/farmacología , Compuestos de Bifenilo/farmacología , Niacinamida/análogos & derivados , Fenilacetatos/farmacología , Vino/análisis , Cromatografía Líquida de Alta Presión , Metacrilatos/farmacología , Niacinamida/farmacología , Fenoles/análisis , Estrobilurinas , Vitis/química , Vitis/efectos de los fármacos
9.
Clin Pharmacol Drug Dev ; 13(2): 208-218, 2024 02.
Artículo en Inglés | MEDLINE | ID: mdl-38185925

RESUMEN

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 .


Asunto(s)
Acetamidas , Queratosis Actínica , Morfolinas , Piridinas , Adulto , Humanos , Queratosis Actínica/tratamiento farmacológico , Queratosis Actínica/diagnóstico , Pomadas , Resultado del Tratamiento , Europa (Continente)
10.
Food Chem ; 403: 134324, 2023 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-36174342

RESUMEN

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.


Asunto(s)
Fungicidas Industriales , Vitis , Compuestos Orgánicos Volátiles , Vino , Vino/análisis , Fungicidas Industriales/análisis , Vitis/química , Odorantes/análisis , Compuestos Orgánicos Volátiles/análisis
11.
Anal Bioanal Chem ; 396(6): 2265-72, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-20135307

RESUMEN

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.


Asunto(s)
Cromatografía de Gases/métodos , Contaminantes Ambientales/sangre , Sangre Fetal/química , Hidrocarburos Halogenados/sangre , Suero/química , Espectrometría de Masa por Ionización de Electrospray/métodos , Preescolar , Contaminantes Ambientales/química , Femenino , Humanos , Hidrocarburos Halogenados/química , Límite de Detección , Masculino
12.
J Proteomics ; 227: 103915, 2020 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-32711165

RESUMEN

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.


Asunto(s)
Saccharomyces cerevisiae , Vino , Clorobencenos , Fermentación , Proteoma , Proteómica , Triazoles , Vino/análisis
13.
Anal Bioanal Chem ; 394(6): 1535-44, 2009 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-19194695

RESUMEN

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.


Asunto(s)
Adyuvantes Farmacéuticos/análisis , Alanina/análogos & derivados , Química Farmacéutica/métodos , Plaguicidas/química , Adyuvantes Farmacéuticos/clasificación , Alanina/análisis , Cromatografía Liquida , Cromatografía de Gases y Espectrometría de Masas , Concentración de Iones de Hidrógeno , Fenómenos Químicos Orgánicos , Polvos , Solventes , Espectrofotometría Ultravioleta , Humectabilidad
14.
Food Chem ; 300: 125223, 2019 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-31362157

RESUMEN

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.


Asunto(s)
Clorobencenos/farmacología , Pirimidinas/farmacología , Triazoles/farmacología , Vitis/efectos de los fármacos , Compuestos Orgánicos Volátiles/metabolismo , Vino , Fermentación , Contaminación de Alimentos/análisis , Frutas/química , Frutas/efectos de los fármacos , Frutas/metabolismo , Fungicidas Industriales , Odorantes/análisis , Vitis/química , Vitis/metabolismo , Compuestos Orgánicos Volátiles/análisis , Vino/análisis , Vino/microbiología , Levaduras/efectos de los fármacos , Levaduras/metabolismo
15.
J Chromatogr A ; 1196-1197: 100-9, 2008 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-18343389

RESUMEN

A gas chromatographic method was developed for simultaneously determining residues of 12 insecticides (acrinathrin, bifenthrin, carbofuran, cyfluthrin, lambda-cyhalothrin, cypermethrin, chlorfenvinphos, deltamethrin, esfenvalerate, fenamiphos, methiocarb and tau-fluvalinate) and 11 fungicides (cyprodinil, fludioxonil, iprodione, metalaxyl, penconazole, pyrimethanil, procymidone tebuconazole, triadimefon, triadimenol and vinclozolin) in leafy vegetables. Samples were extracted with acetonitrile and cleaned-up with graphitized carbon black/primary secondary amine (GCB/PSA) solid-phase extraction (SPE) cartridges using acetonitrile:toluene (3:1, v/v) as eluent. The eluate was finally evaporated and redissolved with 0.5 mL of acetone containing the internal standards (pentachlorobenzene and fenpropathrin) and three analyte protectants (3-ethoxy-1,2-propanediol, d-sorbitol and l-gulonic acid gamma-lactone). The addition of analyte protectants allows to avoid the matrix-induced response enhancement effect on quantitation process with absolute recoveries ca. 100%. Precision (expressed as relative standard deviation) was lower than 10% for all pesticides and finally, limits of detection were also 10-20 times lower than maxima residue levels (MRLs) established by European Regulation. The proposed method was applied to determine pesticide residues in commercial leafy vegetables (lettuce, Swiss chard and spinach) purchased from markets in Orense (NW Spain). Pesticide residues were detected in 84% of the total samples (63 from 75 samples) and pesticide concentrations were higher than MRL in 18 samples.


Asunto(s)
Cromatografía de Gases y Espectrometría de Masas/métodos , Residuos de Plaguicidas/análisis , Hojas de la Planta/química , Verduras/química , Estructura Molecular , Residuos de Plaguicidas/química , Residuos de Plaguicidas/aislamiento & purificación , Estándares de Referencia , Reproducibilidad de los Resultados , Extracción en Fase Sólida
16.
Food Res Int ; 108: 339-346, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29735065

RESUMEN

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.


Asunto(s)
Benzofenonas/análisis , Análisis de los Alimentos/métodos , Jugos de Frutas y Vegetales/análisis , Fungicidas Industriales/análisis , Pirimidinas/análisis , Vitis , Benzofenonas/efectos de la radiación , Fungicidas Industriales/efectos de la radiación , Concentración de Iones de Hidrógeno , Hidrólisis , Cinética , Modelos Teóricos , Fotólisis , Pirimidinas/efectos de la radiación , Temperatura
17.
J Chromatogr Sci ; 44(9): 539-42, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17059679

RESUMEN

A method based on solid-phase extraction (on silica cartridges) and high-performance liquid chromatography (HPLC) followed by diode array UV detection is presented as an analytical tool for screening diquat (DQ) and paraquat (PQ) in drinking waters. The method is useful for quality control laboratories of water companies and beverage industries. Absolute recoveries of DQ and PQ from drinking water (25 mL in all cases), spiked at levels between 0.1, 1.0, and 5.0 microg/L, range from 91% to 103%. Relative standard deviation percentages are between 3% and 11%. Quantitation and detection limits are 70 and 40 ng/L for DQ and 90 and 60 ng/L for PQ, respectively; therefore, these herbicides can be detected and quantitated at levels below the limits established by the European Union.


Asunto(s)
Diquat/análisis , Herbicidas/análisis , Paraquat/análisis , Contaminantes Químicos del Agua/análisis , Cromatografía Líquida de Alta Presión
18.
Water Res ; 102: 561-571, 2016 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-27423406

RESUMEN

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.


Asunto(s)
Etilenotiourea , Fotólisis , Fungicidas Industriales , Hidrólisis , Agua
19.
J Agric Food Chem ; 53(11): 4471-5, 2005 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-15913313

RESUMEN

Residual levels and degradation rates of tebuconazole and dichlofluanid in lettuce plants grown in a greenhouse under agricultural conditions typical of northwestern Spain were studied. Lettuce plants were sprayed four times with a homogeneous 0.2% aqueous solution of Folicur Combi (wettable powder containing 40% dichlofluanid and 10% tebuconazole) at a rate of 2500 g/ha. Samples were collected 1, 5, and 9 days after the first two applications and at times ranging from 1 to 27 days after the last two applications. All samples were stored in a refrigerator at 4 degrees C. Fungicide levels were determined by solid-liquid extraction (SLE) followed by gas chromatography and mass spectrometry detection (GC-MSD). Recovery was good for tebuconazole (98%) but low for dichlofluanid (29%); precision was good (<10% for both analytes), and quantification limits were low (<1.5 mg/kg). Seven days after the last application, dichlofluanid levels were below the maximum allowed limit established in Spain (10 mg/kg), but tebuconazole levels were above the corresponding limit (5 mg/kg). Tebuconazole concentration dynamics was accurately fitted by zeroth- or combined first- and zeroth-order models (depending on variety), but modeling of the behavior of dichlofluanid was less satisfactory, probably due to its instability.


Asunto(s)
Compuestos de Anilina/análisis , Fungicidas Industriales/análisis , Lactuca/química , Triazoles/análisis , Agricultura/métodos , Compuestos de Anilina/administración & dosificación , Fungicidas Industriales/administración & dosificación , Lactuca/crecimiento & desarrollo , Triazoles/administración & dosificación
20.
J Chromatogr A ; 1057(1-2): 193-201, 2004 Nov 19.
Artículo en Inglés | MEDLINE | ID: mdl-15584239

RESUMEN

A static headspace (HS) gas chromatographic method for quantitative determination of residual solvents in a drug substance has been developed according to European Pharmacopoeia general procedure. A water-dimethylformamide mixture is proposed as sample solvent to obtain good sensitivity and recovery. The standard addition technique with internal standard quantitation was used for ethanol, tetrahydrofuran and toluene determination. Validation was performed within the requirements of ICH validation guidelines Q2A and Q2B. Selectivity was tested for 36 solvents, and system suitability requirements described in the European Pharmacopoeia were checked. Limits of detection and quantitation, precision, linearity, accuracy, intermediate precision and robustness were determined, and excellent results were obtained.


Asunto(s)
Cromatografía de Gases/métodos , Preparaciones Farmacéuticas/química , Solventes/análisis , Guías como Asunto , Estándares de Referencia , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
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