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

CERTIFICATION REPORT: The certification of the mass fraction of pesticides in soya: ERM®-BC700

This report describes the production of ERM-BC700, which is a soya 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. Soya beans (Glycine max) originating from Uruguay were sprayed with 11 pesticides in solution. The beans were air dried, cryo-milled and homogenised. 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 outlier was 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 validation studies. The CRM is available in glass vials containing 32 g of cryo-milled soya powder which were sealed under an atmosphere of nitrogen. The minimum amount of sample to be used is 2 gJRC.F.6-Reference Material

Certification of the Mass Fraction of Polycyclic Aromatic Hydrocarbons (PAHs) in Toluene - Certified Reference Materials ERM®-AC213

This report describes the preparation of a calibration solution of polycyclic aromatic hydrocarbons (PAHs) (ERM-AC213) containing benzo[a]pyrene, benz[a]anthracene, cyclopenta[cd]pyrene, chrysene, benzo[b]fluoranthene, benzo[j]fluoranthene, benzo[k]fluoranthene, benzo[ghi]perylene, dibenz[a,h]anthracene, dibenzo[a,l]pyrene, dibenzo[a,e]pyrene, dibenzo[a,i]pyrene, indeno[1,2,3-cd]pyrene, 5-methylchrysene and benzo[c]fluorene and the certification of their content (mass fraction) in the solution. The preparation of the calibrant, homogeneity and stability studies and confirmation measurements with a discussion of the results are described hereafter. Uncertainties were calculated in compliance with the Guide to the Expression of Uncertainty in Measurement (GUM) [1] and include uncertainties due to the processing, purity assessment and possible instability.JRC.DG.D.2-Reference material

IMEP-23: The Eight WFD PAHs in Water in Presence of Humic Acid

IMEP-23 is linked to the Water Framework Directive (WFD). It studied the capability of control laboratories to measure the eight WFD PAHs in the presence of humic acid in a water matrix. Humic acid simulates natural colloidal organic matter and is known to adsorb PAHs. This gives rise to various issues that are of large importance for the control laboratories. Participants' results were benchmarked against the IMEP certified reference values. On average 80 % of the z scores was satisfactory. Zeta scores were calculated for those laboratories who provided an uncertainty estimate. These were less satisfactory and this shows that many laboratories encounter difficulties to provide a reasonable uncertainty estimate.JRC.D.4-Isotope measurement

Determination of Tributyltin (TBT) in Marine Sediment using Pressurised Liquid Extraction - Gas Chromatography - Isotope Dilution Mass Spectrometry (PLE-GC-IDMS): Method Development

An analytical procedure including isotope dilution calibration for the determination of tributyltin (TBT) in sediment samples has been developed. The procedure is based on spiking with isotopically labelled analyte, pressurised liquid extraction (PLE), followed by Grignard-derivatisation and quantification by GC-MS. The method was applied on two unknown sediment samples as a part of an intercomparison exercise organised by the National Research Council of Canada (NRCC) and LGC (UK) on behalf of the Comité Consultatif pour la Quantité de Matière (CCQM). The value found was 103.6 % ± 3.1 % of the certified value by use of the reference material PACS-2, and the detection limit was estimated to be approximately 1.5 ng/g of sediment as Sn. Repeatability and intermediate precision were calculated as coefficient of variation and their values were 1.9 % and 3.2 % respectively. The expanded uncertainty was calculated according to GUM [], and was 6.2 % (coverage factor k=2) and the final values agree with the certified values within their respective uncertainties.JRC.D.2-Reference material

Feasibility study for producing a carrot/potato matrix reference material for 11 selected pesticides at EU MRL level: Material processing, homogeneity and stability assessment

The feasibility study for producing a matrix reference material for selected pesticides in a carrot/potato matrix was investigated. A commercially available baby food (carrot/potato-based mash) was spiked with eleven pesticides at the respective EU maximum residue limits (MRLs), and further processed by either freeing or freeze-drying. Batches of some 150 units were produced per material type. First, the materials were assessed the relative amount of pesticide recovered after processing (ratio of pesticide concentration in the processed material to the initially spiked pesticide concentration). In addition, the materials' homogeneity (bottle to bottle variation), and the short-term (1 month) and mid-term (5 months) stability at different temperatures were assessed. For this, an in-house validated GC-EI-MS method operated in the SIM mode with a sample preparation procedure based on the QuEChERS ("quick, easy, cheap, effective, rugged and safe") principle was applied. Measurements on the frozen material provided the most promising results (smallest analyte losses during production), and also freeze-drying proved to be a suitable alternative processing technique for most of the investigated pesticides. Both the frozen and the freeze-dried material showed to be sufficiently homogeneous for the intended use, and storage at -20°c for 5 months did not reveal any detectable material degradation. The results constitute an important step towards the development of a pesticide matrix reference material.JRC.D.2-Reference material

Production of a Certified Reference Material for the Acrylamide Content in Toasted Bread

The need for a certified matrix reference material (CRM) of acrylamide in a food type matrix was emphasized by the competent authorities as a tool to improve comparability, ensuring accuracy and traceability of analytical results. The Institute for Reference Materials and Measurements (IRMM) responded to the international request by producing a certified reference material, ERM-BD273, containing endogenous acrylamide in a toasted bread food matrix. Heterogeneity of the material between the vials processed was quantified and found to be below 2 %. Potential degradation during storage was also quantified and a shelf life based on this value was established. A collaborative study for material characterisation involved sixteen laboratories applying different analytical methodologies including isotopic dilution mass spectrometry. The certified value for acrylamide in ERM-BD273 is (425 ± 29)ng g-1. The values are traceable to the International System of Units (SI)JRC.D.2-Reference material

Accurate determination of selected pesticides in soya beans by liquid chromatography coupled to isotope dilution mass spectrometry

A sensitive, accurate and simple liquid chromatography coupled with mass spectrometry method for the determination of ten selected pesticides in soya beans has been developed and validated The method is intended for use during the characterisation of selected pesticides in a reference material. In this process, high accuracy and appropriate uncertainty levels associated to the analytical measurements are of utmost importance. The analytical procedure is based on sample extraction by the use of a modified QuEChERS (quick, easy, cheap, effective, rugged, safe) extraction and subsequent clean-up of the extract with C18, PSA and Florisil. Analytes were separated on a C18 column using gradient elution with water-methanol / 2.5 mM ammonium acetate mobile phase, and finally identified and quantified by triple quadrupole mass spectrometry in the multiple reaction monitoring mode (MRM). Reliable and accurate quantification of the analytes was achieved by means of stable isotope-labelled analogues employed as internal standards (IS) and calibration with pure substance solutions containing both, the isotopically labelled and native compounds. Exceptions were made for thiodicarb and malaoxon where the isotopically labelled congeners were not commercially available at the time of analysis. For the quantification of those compounds methomyl-13C215N and malathion-D10 were used respectively. The method was validated according to the general principles covered by DG SANCO guidelines. However, validation criteria were set more stringently. Mean recoveries at the Maximum Residue Limit (MRL) level (five times lower in the case of carbendazim) were in the range of 92-100% with RSDs lower than 7 %. Repeatability and intermediate precision at this level were in the range of 3.9-7.6 % and 1.9-8.7 % respectively. LODs and LOQs were 1.32-6.40 ng g-1 and 4.39-18.16 ng g-1, respectively, in the matrix. The method reliably identifies and quantifies the selected pesticides in soya beans at appropriate uncertainty levels, making it suitable for the characterisation of candidate reference materials.JRC.D.5-Standards for Food Bioscienc

Gas chromatography-isotope dilution mass spectrometry method validation for target pesticides in soybeans

The production of certified reference materials requires the application of highly accurate methods for characterisation. A gas chromatography-isotope dilution mass spectrometry method, setting ambitious performance criteria, was developed for eight selected pesticides in soybeans. Pressurised liquid extraction was followed by automated gel-permeation chromatography and solid-phase extraction clean-up. Pesticides identification respected a Commission Decision and guidelines of the Directorate General for Health and Food Safety (DG SANTE). Reliable quantification involved stable isotopically labelled analogues as internal standards. Validation, according to ISO/IEC 17,025 and DG SANTE guidelines, assessed linearity, LOD/LOQ, trueness, selectivity, precision, stability and robustness. Mean recoveries ranges (83–109%, relative standard deviations < 3%), repeatability (2.2–4.8%), day-to-day variation (0.6–4.2%) and combined uncertainty (1.2–4.2%) were fit for purpose. The method is highly accurate and suitable for certification of the selected pesticides in soybean matrix reference material.JRC.F.6-Reference Material

Development of a new Cucumber Reference Material for Pesticide Residue Analysis: Feasibility Study for Material Processing, Homogeneity and Stability Assessment

The feasibility of the production of a reference material for pesticide residue analysis in a cucumber matrix was investigated. Cucumber was spiked at 0.075 mg/kg with 15 pesticides, namely acetamiprid, azoxystrobin, carbendazim, chlorpyrifos, cypermethrin, diazinon, (α+β)-endosulfan, fenitrothion, imazalil, imidacloprid, iprodione, malathion, methomyl, tebuconazole and thiabendazole. Three different strategies were considered for material processing, based on the physicochemical properties of the vegetable and the target pesticides. As a result, a frozen spiked slurry of fresh cucumber, a spiked freeze-dried cucumber powder, and a freeze-dried cucumber powder spiked by spraying of the powder were studied. The effects of processing and aspects related to material reconstitution were evaluated by monitoring the pesticide levels in the three materials. Two analytical methods based on LC-MS/MS and GC-MS/MS respectively were developed and validated in-house. The spiked freeze-dried cucumber powder was selected as the most feasible material and more exhaustive studies of homogeneity and stability of pesticide residues in the matrix were carried out. Homogeneity between units was satisfactory at a sample intake of dried material as low as 0.1 g. A 9-week stability study was undertaken following an isochronous design at -20 ºC, 4 ºC and 18 ºC, with -70 ºC as reference temperature. The pesticides tested showed adequate stability at -20 ºC during the 9 weeks period as well as at -70 ºC for a period of 18 months. These results constitute a good basis for the development of a new candidate reference material for selected pesticides in a cucumber matrix.JRC.D.5-Standards for Food Bioscienc