Analysis of Chlorothalonil and Three Degradates in Sediment and Soil

Michelle L. Hladik* and Kathryn M. Kuivila
U.S. Geological Survey, 6000 J. Street, Placer Hall, Sacramento, California 95819
J. Agric. Food Chem., 2008, 56 (7), pp 2310–2314
DOI: 10.1021/jf703695s
Publication Date (Web): March 13, 2008
Copyright This article not subject to U.S. Copyright. Published 2008 by the American Chemical Society
* Corresponding author. E-mail address: mhladik@usgs.gov. Phone: (916) 278-3183 . Fax: (916) 278-3013.

Abstract

A method has been developed for the simultaneous extraction of chlorothalonil and three of its degradates (4-hydroxy-2,5,6-trichloroisophthalonitrile, 1-carbamoyl-3-cyano-4-hydroxy-2,5,6-trichlorobenzene, and 1,3-dicarbamoyl-2,4,5,6-tetrachlorobenzene) from soils and sediments; the compounds were extracted using sonication with acetone and isolation of the parent compound and matrix interferences from the degradates by solid phase extraction (SPE). The chlorothalonil fraction underwent further coextracted matrix interference removal with Florisil. The degradates were derivatized with N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA) and chlorotrimethylsilane (TMCS). All compounds were analyzed by gas chromatography–mass spectrometry (GC-MS). Recoveries on a spiked (20 and 200 µg kg−1) sediment ranged from 80% to 91% with calculated limits of detection of 1−5 µg kg−1 dry weight sediment. An additional 20 sediment samples were collected in watersheds from the Southeastern United States where chlorothalonil is used widely on peanuts and other crops. None of the target compounds were detected. Laboratory fortified recoveries of chlorothalonil and its degradates in these environmental sediment samples ranged from 75% to 89%.

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History

  • Published In Issue April 09, 2008
  • Article ASAPMarch 13, 2008
  • Received: December 18, 2007
    Revised: February 5, 2008
    Accepted: February 6, 2008

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