title: Estimation of the uncertainties of extraction and clean-up steps in pesticide residue analysis of plant commodities.
abstract: Extraction and clean-up constitute important steps in pesticide residue analysis. For the correct interpretation of analytical results, uncertainties of extraction and clean-up steps should be taken into account when the combined uncertainty of the analytical result is estimated. In the scope of this study, uncertainties of extraction and clean-up steps were investigated by spiking (14)C-labelled chlorpyrifos to analytical portions of tomato, orange, apple, green bean, cucumber, jackfruit, papaya and starfruit. After each step, replicate measurements were carried out with a liquid scintillation counter. Uncertainties in extraction and clean-up steps were estimated separately for every matrix and method combination by using within-laboratory reproducibility standard deviation and were characterised with the CV of recoveries. It was observed that the uncertainty of the ethyl acetate extraction step varied between 0.8% and 5.9%. The relative standard uncertainty of the clean-up step with dispersive SPE used in the method known as QuEChERS was estimated to be around 1.5% for tomato, apple and green beans. The highest variation of 4.8% was observed in cucumber. The uncertainty of the clean-up step with gel permeation chromatography ranged between 5.3% and 13.1%, and it was relatively higher than that obtained with the dispersive SPE method.
authors.affiliation: Faculty of Engineering and Architecture, Food Engineering Department, Okan University, Istanbul, Turkey. perihan.yolciomeroglu@okan.edu.tr
authors.forename: P Yolci
authors.initials: PY
authors.lastname: Omeroglu
authors.forename: A
authors.initials: A
authors.lastname: Ambrus
authors.forename: D
authors.initials: D
authors.lastname: Boyacioglu
mesh_terms: D004390:Chlorpyrifos / Q000032:analysis / Q000302:isolation & purification; D002850:Chromatography, Gel / Q000379:methods; D005506:Food Contamination / Q000032:analysis*; D006801:Humans; D007306:Insecticides / Q000032:analysis; D010573:Pesticide Residues / Q000032:analysis* / Q000302:isolation & purification; D010945:Plants, Edible / Q000737:chemistry*; D052616:Solid Phase Extraction / Q000379:methods
chemical_list: D007306:Insecticides; D010573:Pesticide Residues; D004390:Chlorpyrifos