title: Contribution of Sample Processing to Variability and Accuracy of the Results of Pesticide Residue Analysis in Plant Commodities.
abstract: Significant reduction of concentration of some pesticide residues and substantial increase of the uncertainty of the results derived from the homogenization of sample materials have been reported in scientific papers long ago. Nevertheless, performance of methods is frequently evaluated on the basis of only recovery tests, which exclude sample processing. We studied the effect of sample processing on accuracy and uncertainty of the measured residue values with lettuce, tomato, and maize grain samples applying mixtures of selected pesticides. The results indicate that the method is simple and robust and applicable in any pesticide residue laboratory. The analytes remaining in the final extract are influenced by their physical-chemical properties, the nature of the sample material, the temperature of comminution of sample, and the mass of test portion extracted. Consequently, validation protocols should include testing the effect of sample processing, and the performance of the complete method should be regularly checked within internal quality control.
authors.affiliation: Retired Scientific Adviser, Hómező u 41, HU1221 Budapest, Hungary.
authors.forename: Árpád
authors.initials: Á
authors.lastname: Ambrus
authors.affiliation: National Food Chain Safety Office Directorate of Plant Protection, Soil Conservation and Agri-environment Pesticide Residue Analytical Laboratory, Miskolc, Blaskovics u 24, H-3500 Miskolc, Hungary.
authors.forename: Judit
authors.initials: J
authors.lastname: Buczkó
authors.affiliation: National Food Chain Safety Office Directorate of Plant Protection, Soil Conservation and Agri-environment Pesticide Analytical Laboratory, Velence, Ország u 23, H-2481 Velence, Hungary.
authors.forename: Kamirán Á
authors.initials: KÁ
authors.lastname: Hamow
authors.affiliation: National Food Chain Safety Office Directorate of Plant Protection, Soil Conservation and Agri-environment Pesticide Analytical Laboratory, Velence, Ország u 23, H-2481 Velence, Hungary.
authors.forename: Viktor
authors.initials: V
authors.lastname: Juhász
authors.affiliation: National Food Chain Safety Office Directorate of Plant Protection, Soil Conservation and Agri-environment Pesticide Analytical Laboratory, Velence, Ország u 23, H-2481 Velence, Hungary.
authors.forename: Etelka
authors.initials: E
authors.lastname: Solymosné Majzik
authors.affiliation: National Food Chain Safety Office Directorate of Plant Protection, Soil Conservation and Agri-environment Pesticide Residue Analytical Laboratory, Miskolc, Blaskovics u 24, H-3500 Miskolc, Hungary.
authors.forename: Henriett
authors.initials: H
authors.lastname: Szemánné Dobrik
authors.affiliation: National Food Chain Safety Office Directorate of Plant Protection, Soil Conservation and Agri-environment Pesticide Residue Analytical Laboratory, Miskolc, Blaskovics u 24, H-3500 Miskolc, Hungary.
authors.forename: Róbert
authors.initials: R
authors.lastname: Szitás
mesh_terms: D053000:Analytic Sample Preparation Methods / Q000379:methods*; D005506:Food Contamination / Q000032:analysis; D005638:Fruit / Q000737:chemistry; D018545:Lactuca / Q000737:chemistry*; D018551:Solanum lycopersicum / Q000737:chemistry*; D013058:Mass Spectrometry / Q000592:standards; D010573:Pesticide Residues / Q000032:analysis*; D003313:Zea mays / Q000737:chemistry*
chemical_list: D010573:Pesticide Residues
keywords: internal quality control; method validation; pesticide residues; stability of pesticide residues; uncertainty of pesticide residue results