Dissipation,half-lives,and mass spectrometric identification of chlorpyrifos and its two metabolites on field-grown collard and kale |
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Authors: | George F Antonious Eric T Turley Mutari Abubakari John C Snyder |
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Institution: | 1. Division of Environmental Studies, College of Agriculture, Food Science, and Sustainable Systems, Kentucky State University, Frankfort, Kentucky, USA;2. Department of Horticulture, University of Kentucky, Lexington, Kentucky, USA |
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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 T1/2 of 6.5 days compared to kale (T1/2 of 1.9 days). |
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Keywords: | GC-MSD half-life metabolites chlorpyrifos oxon 3 5 6-trichloro-2-pyridinol |
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