title: Development of a new cucumber reference material for pesticide residue analysis: feasibility study for material processing, homogeneity and stability assessment.
abstract: 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 each of the 15 selected pesticides (acetamiprid, azoxystrobin, carbendazim, chlorpyrifos, cypermethrin, diazinon, (α + β)-endosulfan, fenitrothion, imazalil, imidacloprid, iprodione, malathion, methomyl, tebuconazole and thiabendazole) respectively. Three different strategies were considered for processing the material, 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 the powder were studied. The effects of processing and aspects related to the reconstitution of the material were evaluated by monitoring the pesticide levels in the three materials. Two separate analytical methods based on LC-MS/MS and GC-MS/MS were developed and validated in-house. The spiked freeze-dried cucumber powder was selected as the most feasible material and more exhaustive studies on homogeneity and stability of the pesticide residues in the matrix were carried out. The results suggested that the between-unit homogeneity was satisfactory with a sample intake of dried material as low as 0.1 g. A 9-week isochronous stability study was undertaken at -20 °C, 4 °C and 18 °C, with -70 °C designated as the reference temperature. The pesticides tested exhibited adequate stability at -20 °C during the 9-week period as well as at -70 °C 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.
authors: European Commission, Joint Research Centre, Institute for Reference Materials and Measurements (IRMM), 111 Retieseweg, 2440, Geel, Belgium.
authors: Susana
authors: S
authors: Grimalt
authors: Stefan
authors: S
authors: Harbeck
authors: Penka
authors: P
authors: Shegunova
authors: John
authors: J
authors: Seghers
authors: Berit
authors: B
authors: Sejerøe-Olsen
authors: Håkan
authors: H
authors: Emteborg
authors: Marta
authors: M
authors: Dabrio
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods / Q000592:standards; D018553:Cucumis sativus / Q000737:chemistry*; D005240:Feasibility Studies; D005504:Food Analysis / Q000379:methods / Q000592:standards*; D005506:Food Contamination / Q000032:analysis*; D005612:Freeze Drying; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods / Q000592:standards; D010573:Pesticide Residues / Q000032:analysis* / Q000592:standards; D012015:Reference Standards; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods / Q000592:standards
chemical_list: D010573:Pesticide Residues
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