title: Method validation and dissipation dynamics of chlorfenapyr in squash and okra.
abstract: QuEChERS method combined with GC-IT-MS was developed and validated for the determination of chlorfenapyr residues in squash and okra matrices. Method accuracy, repeatability, linearity and specificity were investigated. Matrix effect was discussed. Determination coefficients (R(2)) were 0.9992 and 0.9987 in both matrices. LODs were 2.4 and 2.2μg/kg, while LOQs were 8.2 and 7.3μg/kg. Method accuracy ranged from 92.76% to 106.49%. Method precision RSDs were ⩽12.59%. A field trial to assess chlorfenapyr dissipation behavior was carried out. The developed method was employed in analyzing field samples. Dissipation behavior followed first order kinetics in both crops. Half-life values (t1/2) ranged from 0.2 to 6.58days with determination coefficient (R(2)) ranged from 0.78 to 0.96. The developed method was utilized for surveying chlorfenapyr residues in squash and okra samples collected from the market. Monitoring results are discussed.
authors.affiliation: Plant Production and Protection Department, College of Agriculture and Veterinary Medicine, Qassim University, 51452 Buraydah P.O. Box 6622, Al-Qassim, Saudi Arabia; Department of Plant Protection, Faculty of Agriculture, Ain Shams University, P.O. Box 68 Hadayek Shoubra, 11241 Cairo, Egypt. Electronic address: sherifbiomy@yahoo.com.
authors.forename: Sherif B
authors.initials: SB
authors.lastname: Abdel Ghani
authors.affiliation: Food Safety Laboratory, Al-Qassim Municipality, Buraydah, Al-Qassim, Saudi Arabia; Department of Pesticides Residues and Environmental Pollution, Central Agricultural Pesticide Laboratory, Agricultural Research Center, Giza 12618, Egypt.
authors.forename: Osama I
authors.initials: OI
authors.lastname: Abdallah
mesh_terms: D028483:Abelmoschus / Q000737:chemistry*; D028464:Cucurbita / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D057230:Limit of Detection; D010573:Pesticide Residues / Q000032:analysis*; D011722:Pyrethrins / Q000378:metabolism*
chemical_list: D010573:Pesticide Residues; D011722:Pyrethrins; C436643:chlorfenapyr
keywords: Chlorfenapyr residues; Dissipation; GCMS; Method validation; Okra; Squash