title: Miniaturisation and optimisation of the Dutch mini-Luke extraction method for implementation in the routine multi-residue analysis of pesticides in fruits and vegetables.
abstract: This paper presents the validation and further miniaturisation of the well-known Dutch mini-Luke method for high water and acid content matrices for 175 pesticides amenable to liquid- and gas chromatography-mass spectrometry. For optimisation of the method, recovery tests with different sample/extraction solvent ratios, varying amounts of dichloromethane and salts were performed with fifty representative pesticides. Solvent consumption could be reduced considerably, especially for the dichloromethane (by a factor of 3). Recovery studies performed with lettuce and orange matrix spiked at 0.005, 0.01 and 0.02 mg/kg yielded average recoveries in the range 70-120% with relative standard deviation values below 20% for almost all the pesticides tested. The linearity over three orders of magnitude was demonstrated (r(2) > 0.99). The matrix effect could be considered as not significant. The limit of quantification was 0.005 mg/kg for 96% of the compounds. The optimised New Dutch mini-Luke ("NL"-) method was applied successfully in routine analysis and the EUPT FV-16 sample.
authors: Agrifood Campus of International Excellence (ceiA3), European Union Reference Laboratory for Pesticide Residues in Fruit & Vegetables, University of Almeria, Almería, Spain; NVWA - Netherlands Food and Consumer Product Safety Authority, Laboratory of Food and Feed Safety, National Reference Laboratory for Pesticide Residues in Food and Feed, Wageningen, The Netherlands. Electronic address: analozano@ual.es.
authors: Ana
authors: A
authors: Lozano
authors: NVWA - Netherlands Food and Consumer Product Safety Authority, Laboratory of Food and Feed Safety, National Reference Laboratory for Pesticide Residues in Food and Feed, Wageningen, The Netherlands.
authors: Barbara
authors: B
authors: Kiedrowska
authors: NVWA - Netherlands Food and Consumer Product Safety Authority, Laboratory of Food and Feed Safety, National Reference Laboratory for Pesticide Residues in Food and Feed, Wageningen, The Netherlands.
authors: Jos
authors: J
authors: Scholten
authors: NVWA - Netherlands Food and Consumer Product Safety Authority, Laboratory of Food and Feed Safety, National Reference Laboratory for Pesticide Residues in Food and Feed, Wageningen, The Netherlands.
authors: Marijke
authors: M
authors: de Kroon
authors: NVWA - Netherlands Food and Consumer Product Safety Authority, Laboratory of Food and Feed Safety, National Reference Laboratory for Pesticide Residues in Food and Feed, Wageningen, The Netherlands.
authors: André
authors: A
authors: de Kok
authors: Agrifood Campus of International Excellence (ceiA3), European Union Reference Laboratory for Pesticide Residues in Fruit & Vegetables, University of Almeria, Almería, Spain.
authors: Amadeo R
authors: AR
authors: Fernández-Alba
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods; D005506:Food Contamination / Q000032:analysis*; D005638:Fruit / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D013058:Mass Spectrometry / Q000379:methods; D008752:Methylene Chloride; D008904:Miniaturization / Q000379:methods*; D009426:Netherlands; D010573:Pesticide Residues / Q000032:analysis*; D010575:Pesticides / Q000032:analysis; D015203:Reproducibility of Results; D012997:Solvents; D014675:Vegetables / Q000737:chemistry*
chemical_list: D010573:Pesticide Residues; D010575:Pesticides; D012997:Solvents; D008752:Methylene Chloride
keywords: Gas chromatography; Liquid chromatography; Mass spectrometry; Miniaturisation; New Dutch mini-Luke (NL-) method; Validation