title: Dissipation, half-lives, and mass spectrometric identification of chlorpyrifos and its two metabolites on field-grown collard and kale.
abstract: The persistence and fate of chlorpyrifos and its two metabolites, chlorpyrifos-oxon and the 3, 5, 6-trichloro-2-pyridinol (TCP) break-down product were investigated on kale and collard leaves under field conditions. A simultaneous extraction and quantification procedure was developed for chrorpyrifos and its two main metabolites. Residues of chlorpyrifos, chlorpyrifos oxon, and TCP were determined using a gas chromatograph (GC) equipped with an electron capture detector (GC/ECD). Chlorpyrifos metabolites were detectable up to 23 days following application. Residues were confirmed using a GC equipped with a mass selective detector (GC/MSD) in total ion mode. Initial residues of chlorpyrifos were greater on collard (14.5 µg g-1) than kale (8.2 µg g-1) corresponding to half-lives (T1/2) values of 7.4 and 2.2 days, respectively. TCP, the hydrolysis product, was more persistent on collards with an estimated T1/2of 6.5 days compared to kale (T1/2of 1.9 days).
authors.affiliation: a Division of Environmental Studies, College of Agriculture, Food Science, and Sustainable Systems, Kentucky State University , Frankfort , Kentucky , USA.
authors.forename: George F
authors.initials: GF
authors.lastname: Antonious
authors.affiliation: a Division of Environmental Studies, College of Agriculture, Food Science, and Sustainable Systems, Kentucky State University , Frankfort , Kentucky , USA.
authors.forename: Eric T
authors.initials: ET
authors.lastname: Turley
authors.affiliation: b Department of Horticulture , University of Kentucky , Lexington , Kentucky , USA.
authors.forename: Mutari
authors.initials: M
authors.lastname: Abubakari
authors.affiliation: b Department of Horticulture , University of Kentucky , Lexington , Kentucky , USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Snyder
mesh_terms: D001937:Brassica / Q000737:chemistry* / Q000187:drug effects; D004390:Chlorpyrifos / Q000031:analogs & derivatives / Q000032:analysis* / Q000378:metabolism / Q000493:pharmacokinetics*; D002849:Chromatography, Gas / Q000295:instrumentation / Q000379:methods; D006207:Half-Life; D006868:Hydrolysis; D007629:Kentucky; D013058:Mass Spectrometry / Q000379:methods; D010573:Pesticide Residues / Q000032:analysis / Q000493:pharmacokinetics; D018515:Plant Leaves / Q000737:chemistry; D011728:Pyridones / Q000032:analysis / Q000493:pharmacokinetics
chemical_list: D010573:Pesticide Residues; D011728:Pyridones; C009618:O,O-diethyl O-3,5,6-trichloro-2-pyridyl phosphate; C012587:3,5,6-trichloro-2-pyridinol; D004390:Chlorpyrifos
keywords: 3, 5, 6-trichloro-2-pyridinol; GC-MSD; chlorpyrifos oxon; half-life; metabolites