Omeroglu, P. YolciAmbrus, A.Boyacioglu, D.2024-05-252024-05-25201331944-00491944-005710.1080/19440049.2012.7464752-s2.0-84872613726https://doi.org/10.1080/19440049.2012.746475https://hdl.handle.net/20.500.14517/863Omeroglu, Perihan Yolci/0000-0001-8254-3401; BOYACIOGLU, DILEK/0000-0002-8160-0619Extraction 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 14C-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.eninfo:eu-repo/semantics/closedAccessethyl acetate extractionextraction and clean-upgel permeation chromatographymeasurement uncertaintypesticide residuesQuEChERSArticleQ2Q1302308320WOS:00031367090001223216411