CERTIFICATION REPORT The certification of the mass fraction of pesticides in cucumber: ERM-BC403

This report describes the production of ERM®-BC403, which is a cucumber material certified for the mass fraction of selected pesticides. This material was produced following ISO Guide 34:2009 and is certified in accordance with ISO Guide 35:2006. Cucumbers from a biodynamic farm were used as base material. The cucumbers were transformed into slurry, freeze-dried and cryogenically milled. The obtained product was partially reconstituted with water and a separate portion was spiked with a pesticide mixture. The contaminated portion was then mixed with the rest of the material, homogenised and accurately dispensed into 100-ml vials. A second freeze-drying cycle was applied with the vials placed directly in the freeze-dryer. Prior to analysis the resulting sponge of dry cucumber must be reconstituted with a specific volume of water. Between-unit homogeneity was quantified and stability during dispatch and storage were assessed in accordance with ISO Guide 35:2006 [ ]. The material was characterised by an interlaboratory comparison of laboratories of demonstrated competence and adhering to ISO/IEC 17025. Technically invalid results were removed but no outliers were eliminated on statistical grounds only. Uncertainties of the certified values were calculated in accordance with the Guide to the Expression of Uncertainty in Measurement (GUM) [ ] and include uncertainties related to possible inhomogeneity, instability and characterisation. The material is intended for the quality control / assessment of method performance. As with any reference material, it can be used for establishing control charts or used for validation of analytical methods. The CRM is available in sets of two glass vials containing each approximately 3.2 g of dried material. The vials were sealed under an atmosphere of argon. The minimum amount of sample to be used is 2.5 g of the reconstituted material.JRC.F.6-Reference Material

the NEMESIS project's quest for novel biomarkers, evidence on adverse effects, and efficient methodologies

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Use of a Real-Time Remote Monitoring Network (RTRM) to Characterize the Guadalquivir Estuary (Spain)

The temporal variability of hydrological variables in the Guadalquivir estuary was examined during three years through a real-time remote monitoring network (RTRM). The network was developed with the aim of studying the influence of hydrodynamical and hydrological features within the estuary on the functioning of the pelagic ecosystem. Completing this data-gathering network, monthly cruises were performed in order to measure biogeochemical variables that are indicative of the trophic status of the aquatic environment. The results showed that several sources of physical forcing, such as wind, tide-associated currents and river discharge were responsible for the spatio-temporal patterns of dissolved oxygen, salinity and turbidity in the estuary. The analysis was conducted under tidal and flood regime, which allowed us to identify river discharge as the main forcing agent of the hydrology inside the estuary. In particular, episodes of elevated turbidity detected by the network, together with episodes of low salinity and dissolved oxygen were closely related to the increase in water supply from a dam located upstream. The network installed provided accurate data that can be rapidly used for research or educational applications and by policy-makers or agencies in charge of the management of the coastal area

Nuevas aportaciones de LC-MS con analizadores de triple cuadrupolo y tiempo de vuelo en el análisis de residuos de plaguicidas y metabolitos en alimentos de origen vegetal.

A lo largo de esta Tesis Doctoral se ha estudiado el potencial analítico del acoplamiento instrumental cromatografía líquida-espectrometría de masas en tándem, haciendo uso de analizadores de triple cuadrupolo (QqQ) e híbrido cuadrupolo-tiempo de vuelo (QTOF), con el objetivo principal de investigar la presencia de residuos de plaguicidas y sus metabolitos en alimentos de origen vegetal. En ese sentido, la tesis aborda uno de los aspectos más importantes en el campo de la salud pública, ya que la presencia de plaguicidas y sus metabolitos en alimentos es un tema de interés toxicológico. La tesis está dividida en dos grandes bloques: un primer bloque centrado en el desarrollo de métodos analíticos mediante LC-QqQ para la determinación de residuos de plaguicidas y sus metabolitos con especial interés por sus características físico-químicas, que dificultan su inclusión en métodos multirresiduales de análisis; un segundo bloque dirigido a la investigación de las capacidades del analizador (Q)TOF tanto en el análisis de plaguicidas, como en la búsqueda e identificación de metabolitos de plaguicidas

Review of analytical methods for the determination of pesticide residues in grapes

This review paper presents an overview of analytical methods used for the analysis of pesticide residues in grapes and by-products in the last decade. The most widely used detection technique used for the determination of pesticides in grapes is mass spectrometry combined with gas and/or liquid chromatography. Multi-residue methods with selective sample treatment methodologies have been developed for this purpose. However, this review focuses not only on these common multi-residue methods but also on specific methodologies for the analysis of pesticides in grapes and by-products. Finally the limitations of multi-residue methods and future perspectives and trends for pesticide residue analysis in grapes are reviewed.JRC.D.5-Standards for Food Bioscienc

Investigation of pesticide metabolites in food and water by LC-TOF-MS

We illustrate the potential of liquid chromatography with (quadrupole) time-of-flight mass spectrometry [LC-(Q)TOF-MS] in investigating the presence of pesticide metabolites in food and water samples. The higher polarity of metabolites compared to their parent pesticides makes the combination of LC [both high-performance (HPLC) and ultra-performance (UPLC)] with TOF-MS one of the most appropriate techniques for their analysis, mainly from a qualitative point of view. Both target analysis and non-target analysis have been explored making use of this technique. Target analysis is typically applied in the inspection of maximum residue limits in food, when a relevant metabolite is included in the residue definition for toxicological reasons or its presence in significant amounts. Within this field, LC-TOF-MS, thanks to its intrinsic characteristics of high sensitivity in full-scan acquisition mode and elevated mass accuracy, has great potential for qualitative purposes, and it allows detection and reliable identification of a large number of metabolites in only one chromatographic run without the need for re-analysis. The latest generations of TOF instruments have also been successfully applied for quantitative purposes. By contrast with food analysis, for drinking water, most regulations of residues do not specify which pesticide metabolites must be included in analysis, and even less so for environmental waters. In such cases, analytical laboratories can focus analysis on a list of (normally) a few target metabolites, or on non-target analysis, where the objective is to identify (pre-defined) metabolites in samples without previously selecting them. We review the use of LC-TOF-MS and LC-(Q)TOF-MS in pesticide-metabolite analysis, considering different approaches:*multi-residue pesticide analysis, where several metabolites are included within the list of target analytes;*investigation of pesticide metabolites in samples that were positive for selected pesticides in previous target analysis;*investigation of metabolites in pesticide-metabolism or degradation studies, typically in laboratory or field experiments under controlled conditions; and,*non-target analysis, where there is no previous information or restrictions on the compounds to be searched in the samples. We show that LC-(Q)TOF-MS is at present one of the most advanced and efficient techniques for screening and identification of pesticide metabolites in food and water. © 2008 Elsevier Ltd. All rights reserved

Quantification, confirmation and screening capability of UHPLC coupled to triple quadrupole and hybrid quadrupole time-of-flight mass spectrometry in pesticide residue analysis

The potential of three mass spectrometry (MS) analyzers (triple quadrupole, QqQ; time of flight, TOF; and quadrupole time of flight, QTOF) has been investigated and compared for quantification, confirmation and screening purposes in pesticide residue analysis of fruit and vegetable samples. For this purpose, analytical methodology for multiresidue determination of 11 pesticides, taken as a model, has been developed and validated in nine food matrices for the three mass analyzers coupled to ultra high pressure liquid chromatography. In all cases, limits of quantification around 0.01 mg/kg were reached, fulfilling the most restrictive case of baby-food analysis. Regarding absolute sensitivity, the lower limits of detection were obtained, as expected, for QqQ (100 fg), whereas slightly higher limits (300 fg) were obtained for both TOF and QTOF. Confirmative capacity of each analyzer was studied for each analyte based on the identification points (IPs) criterion, useful for a comprehensive comparison. QTOF mass analyzer showed the highest confirmatory capacity, although QqQ normally led to sufficient number of IPs, even at lower concentration levels. The potential of TOF MS was also investigated for screening purposes. To this aim, around 50 commercial fruits and vegetables samples were analyzed, searching for more than 400 pesticides. TOF MS proved to be an attractive analytical tool for rapid detection and reliable identification of a large number of pesticides thanks to the full spectrum acquisition at accurate mass with satisfactory sensitivity. This process is readily boosted when combined with specialized software packages, together with theoretical exact mass databases. Several pesticides (e.g. carbendazim in citrus and indoxacarb in grape) were detected in the samples. Further unequivocal confirmation of the identity was performed using reference standards and/or QTOF MS/MS experiments

Use of ultra-high-pressure liquid chromatography–quadrupole time-of-flight MS to discover the presence of pesticide metabolites in food samples

In this paper we illustrate the use of two different methodologies to investigate the presence of pesticide metabolites in parent pesticide-positive food samples, using ultra-high-pressure liquid chromatography coupled to hybrid quadrupole time-of-flight (UHPLC–QTOF) mass spectrometry. First, a common fragmentation pathway between the parent pesticide and its metabolites has been considered to search for metabolites in two positive market samples (imazalil in lemon, chlorpyrifos in grape). Secondly, olive oil samples from field residue trials were used for automated application of comparative software (MetaboLynx), which was used with treated and untreated samples to search for expected and unexpected metabolites of phosmet. One of the main objectives when using these approaches was to avoid the tedious manual searching for potential metabolites within the huge amount of information contained in the total ion chromatogram acquired by TOF MS. The common fragmentation approach applied to TOF MS full-acquisition data, considering an enhanced fragmentation in the collision cell, has allowed the discovery of two metabolites of imazalil (1-[2-(2,4-dichlorophenyl)-2-hydroxyethyl]-1H-imidazole and 1-[2-(2,4-dichlorophenyl)-2-oxoethyl]-1H-imidazole) in a lemon positive sample, as well as another two metabolites of chlorpyrifos (chlorpyrifos-oxon and 3,5,6-trichloro-2-pyridinol) in a grape positive sample. Moreover, MetaboLynx application to TOF MS data, without promoting fragmentation, from treated and untreated olive oil samples has been helpful in detecting the metabolite phosmet-oxon. In both strategies, every metabolite detected by TOF MS was confirmed using QTOF and/or triple quadrupole instruments. Accurate masses given by TOF MS together with the valuable information on product ions given by QTOF MS/MS experiments were crucial for the unambiguous identification of metabolites

Optimisation and validation of a specific analytical method for the determination of thiram residues in fruits and vegetables by LC–MS/MS

Thiram is a non-systemic dithiocarbamate fungicide, which is easily degraded during sample preparation since it is affected by pH, matrix components and temperature. In this work, specific methodology for thiram analysis in vegetable (eggplant and lettuce) and fruit (strawberry) samples has been developed based on liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS). Minimising thiram degradation during standards storage and sample preparation was carefully studied. The effect of low temperature (about 5 °C), addition of a dehydrating agent (Na2SO4 anhydrous), pH regulator (NaHCO3), and enzymatic activity reduction (EDTA) during extraction was evaluated. The optimised procedure was validated for eggplants, lettuces, and strawberries. Satisfactory recoveries, between 80% and 106%, and relative standard deviations below 10% were obtained at 0.1 and 0.01 mg/kg fortification levels (n = 5). Limits of detection below 0.0012 mg/kg were achieved. The validated method has been applied to eggplant and lettuce samples collected from different field trials as well as several strawberry and apple samples