Publications by authors named "Marta Vargas-Perez"

Infant formulas (IF) can contain harmful chemical substances, such as pesticides and mycotoxins, resulting from the contamination of raw materials and inputs used in the production chain, which can cause adverse effects to infants. Therefore, the quick, easy, cheap, effective, rugged, and safe (QuEChERS) methodology prior ultra-high performance liquid chromatography coupled to triple quadrupole mass spectrometry (UHPL-QqQ-MS/MS) analysis was applied for the determination of 23 contaminants, in 30 samples of Brazilian IF. The method was validated in terms of limit of detection (0.

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Background: Fluopyram is a pesticide widely used in tomato and cucumber crops cultivation to control fungal diseases that develop especially in environments with moderate temperatures and high humidity, such as in a greenhouse. The pathway of fluopyram dissipation has been monitored in cucumber and cherry tomato under greenhouse conditions.

Results: In the greenhouse trials, cherry tomato and cucumber were treated by irrigation water with the commercial product at the manufacturer's recommended dose and double dose.

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A novel application, which combines targeted and non-targeted approaches, using gas chromatography high-resolution mass spectrometry (GCHRMS) for multiresidue analysis of pesticides in fruits and vegetables is proposed; the aim is to add information to that obtained from targeted methods to be used in pesticide residues monitoring laboratories. Extract from fruit samples obtained with QuEChERS method are analysed with two different approaches: a first step in targeted mode in full scan, and a second step in non-targeted mode with HRMS deconvolution. The targeted method was validated for 191 pesticides, in banana, watermelon, pear and strawberry, with recoveries within 70-120%, precision-RSD <20%, linearity between 1-100 µg/kg (5-100 µg/kg in strawberry) and quantification limits (LOQs) of 5 µg/kg.

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The aim of this study is to understand the levels and behaviour of the herbicide propoxycarbazone in environmental compartments, which are poorly characterized considering degradation products that might reach either surface water as groundwater or soil samples. To this end, an analytical method, based on ultra-high performance liquid chromatography (UHPLC) coupled with Orbitrap mass spectrometry (MS), has been developed to determine the parent compound and its transformation products in soils and water. In addition, a set of laboratory trials has been designed to address the dissipation process of propoxycarbazone formulation in both environmental substrates.

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This study reports a method for propoxycarbazone pesticide determination including its metabolite in food commodities (lettuce, beetroot, soybean meal and honey). Both compounds were extracted, and samples cleaned using a buffered QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method based on the AOAC Official Method, followed by ultra high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Both matrix-matched calibration curves showed good linearity (R = 0.

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