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Garcia-Chao M.,Galician Institute for Food Quality INGACAL | Agruna M.J.,Galician Institute for Food Quality INGACAL | Calvete G.F.,Galician Institute for Food Quality INGACAL | Sakkas V.,University of Ioannina | And 2 more authors.
Analytica Chimica Acta | Year: 2010

The use of pesticides to protect crops against plagues and insects is one of the most important ways to assure agricultural quality and productivity. However, bad application practices may cause the contamination of different environmental compartments and animal species, as a consequence of migration or accumulation of those compounds. Fipronil, imidacloprid and thiametoxam are systemic or systemic-like insecticides widely used in maize crops. Their heavy action in the nervous system of target insects also means a high toxicity to non-target pollinator insects such as honey bees which can get in touch with them through pollen and nectar during foraging activities. These insecticides have even been suspected to cause a significant decrease of honeybee colonies that has been observed in many countries since the past decade. Since September 1st 2008, the European Commission set new MRLs in food and feed of plant and animal origin. The pesticides included in this study have MRLs in honey and pollen between 10 and 50ngg-1. In the present work, an analytical method was developed with the aim of determining residues of fipronil and some of its metabolites (fipronil sulfone, fipronil sulfide, fipronil desulfinyl and fipronil carboxamide), thiamethoxam and imidacloprid in honey and pollen samples. The extraction optimization was performed using a Doehlert experimental design by studying two factors, the mixture and the ratio of solvents used. Prior to the extraction procedure, raw hive samples containing honey, pollen and wax were centrifuged at 4000. rpm. The upper solid material was removed, and 1. g of the lower phase was mixed with 3. mL of the optimized mixture of methanol/water (10/90). The extract was passed through a florisil cartridge and the target compounds were eluted with methanol and analysed by LC-MS/MS in selective reaction monitoring (SRM) mode. The method was validated according to the guidelines included in the SANCO/10684/2009 document and the ISO 11843 standard for the following parameters: decision limit (CCα), detection capability (CCβ), recovery, repeatability and reproducibility at 0.5, 1 and 1.5 folds the MRLs. Ion suppression/enhancement effects into the ion source were also assessed. The CCβ values were included between 0.83 and 4.83ngg-1, well below the current MRLs. The validated method was applied to the determination of the target pesticides in 91 samples collected in colonies from 73 apiaries of NW Spain (two sampling campaigns during 2008). None of the target insecticides were detected among all the collected samples. © 2010 Elsevier B.V. Source


Vila M.,University of Santiago de Compostela | Lamas J.P.,University of Santiago de Compostela | Garcia-Jares C.,University of Santiago de Compostela | Dagnac T.,Galician Institute for Food Quality INGACAL | Llompart M.,University of Santiago de Compostela
Journal of Chromatography A | Year: 2015

A methodology based on pressurized liquid extraction (PLE) followed by gas chromatography-tandem mass spectrometry (GC-MS/MS) has been developed for the simultaneous analysis of different classes of UV filters including methoxycinnamates, benzophenones, salicylates, p-aminobenzoic acid derivatives, and others in cosmetic products. The extractions were carried out in 1mL extraction cells and the amount of sample extracted was only 100mg. The experimental conditions, including the acetylation of the PLE extracts to improve GC performance, were optimized by means of experimental design tools. The two main factors affecting the PLE procedure such as solvent type and extraction temperature were assessed. The use of a matrix matched approach consisting of the addition of 10μL of diluted commercial cosmetic oil avoided matrix effects. Good linearity (R2>0.9970), quantitative recoveries (>80% for most of compounds, excluding three banned benzophenones) and satisfactory precision (RSD<10% in most cases) were achieved under the optimal conditions. The validated methodology was successfully applied to the analysis of different types of cosmetic formulations including sunscreens, hair products, nail polish, and lipsticks, amongst others. © 2015 Elsevier B.V. Source


Celeiro M.,University of Santiago de Compostela | Llompart M.,University of Santiago de Compostela | Lamas J.P.,University of Santiago de Compostela | Lores M.,University of Santiago de Compostela | And 2 more authors.
Journal of Chromatography A | Year: 2014

Ultrasound-assisted extraction (UAE) and pressurized liquid extraction (PLE) followed by gas chromatography-triple quadrupole-mass spectrometry (GC TQ-MS) were used for the rapid determination of 11 fungicides (metalaxyl, cyprodinil, procymidone, iprovalicarb, myclobutanyl, kresoxim-methyl, benalaxyl, fenhexamide, tebuconazole, iprodione and dimethomorph) in white grape bagasse. The extractions were optimized on real non-spiked samples by means of experimental design and the optimal conditions were selected to achieve the method validation. The PLE procedure showed much higher efficiency than UAE for the target fungicides. Under the selected extraction conditions, PLE showed satisfactory linearity, repeatability and reproducibility. Recoveries for the majority of studied fungicides were higher than 80% with relative standard deviations (RSD) lower than 12%. Limits of detection (LODs) for GC TQ-MS were very low, at the sub ngg-1 for the majority of the target fungicides, well below the European maximum residue limits (MRLs) for wine and table grapes, and vine leaves. Eighteen white grape bagasse samples were analyzed and nine out of eleven targets were detected in the samples. Seven of them were detected in more than 50% of the samples and most samples contained at least four of the target analytes. The most frequently found compounds were tebuconazole and dimethomorph with concentrations between 1.6-130 and 2.0-1788ngg-1, respectively. Some samples showed high levels of many of the studied fungicides (high ngg-1, even μgg-1 for cyprodinil, fenhexamide, iprodione and dimethomorph), but all of them below the European maximum residue limits (MRLs) for wine grapes. © 2014 Elsevier B.V. Source


Garcia-Jares C.,University of Santiago de Compostela | Becerril-Bravo E.,National Autonomous University of Mexico | Sanchez-Prado L.,University of Santiago de Compostela | Lamas J.P.,University of Santiago de Compostela | And 2 more authors.
International Journal of Environmental Analytical Chemistry | Year: 2014

Ultrasound-assisted emulsification-microextraction (USAEME) demonstrated its applicability for the analysis in waters of 2-phenylphenol (PP), 4-tert-butylphenol (TBP), benzothiazole (BTZ) and piperonyl butoxide (PBO), belonging to different chemical families, and all of them characterised by its high production volume. In the developed USAEME procedure, compounds were extracted in chloroform from 10 mL of water sample during only 5 min. The addition of derivatising reagents has been studied as part of the optimisation process. The optimised procedure provided an efficient and exhaustive extraction with the advantage that the extract was ready for GC analysis. The method was validated using real environmental water samples, obtaining recoveries between 68 and 111%, RSD values ≤10%, and limits of quantification at the sub-ng per millilitre level (0.004-0.072 μg L-1). The application of the method to the determination of the targets in different environmental waters showed their presence in most samples.In addition, the method allowed the study of the behaviour of the compounds in the presence of chlorine as disinfection agent, reporting for the first time that BTZ and PBO remained stable even at 4 mg L-1 of chlorine concentration, whereas the phenolic compounds (TBP and PP) required low chlorination levels to be transformed into mono- and di-chlorinated derivatives. © 2013 Taylor & Francis. Source


Alvarez-Rivera G.,University of Santiago de Compostela | Dagnac T.,Galician Institute for Food Quality INGACAL | Lores M.,University of Santiago de Compostela | Garcia-Jares C.,University of Santiago de Compostela | And 3 more authors.
Journal of Chromatography A | Year: 2012

In this work, the development of a new efficient methodology applying, for the first time, matrix solid phase dispersion (MSPD) for the determination of sensitizer isothiazolinone biocides in cosmetics and household products - 2-methyl-3-isothiazolinone (MI), 5-chloro-2-methyl-3-isothiazolinone (CMI), 1,2-benzisothiazolinone (BzI) and 2-octyl-3-isothiazolinone (OI) - is described. The main factors affecting the MSPD extraction procedure, the dispersive phase and the elution solvent, are assessed and optimized through a multicategorical experimental design, using a real cosmetic sample. The most suitable extraction conditions comprise the use of 2g of florisil as dispersive phase and 5mL of methanol as elution solvent. Subsequently, the extract is readily analyzed by HPLC-MS/MS without any further clean-up or concentration steps. Method performance was evaluated demonstrating to have a broad linear range (R2>0.9980) and limits of detection (LOD) and quantification (LOQ) at the low nanogram per gram level, which are well below the required limits for UE regulation compliance. Satisfactory recoveries above 80%, except for MI (mean values close to 60%), were obtained. In all cases, the method precision (% RSD) was lower than 7%, making this low cost extraction method reliable for routine control. The validated methodology was finally applied to the analysis of a wide variety of cosmetics and household products. Most of the real samples analyzed have been shown to comply with the current European Cosmetic Regulation, although the results obtained for some rinse-off cosmetics (e.g. baby care products) revealed high isothiazolinone content. © 2012 Elsevier B.V. Source

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