Multiresidue determination of pesticides in high-organic-content soils by solid-phase extraction and gas chromatography/mass spectrometry

A muitiresidue method based on solid-phase extraction cleanup and gas chromatography/ion trap mass spectrometry was developed to analyze 120 pesticides and pesticide metabolites in 2 soils with organic matter contents of 4.0 and 5.2%. Among the pesticides and the pesticide metabolites studied (almost all of which were spiked into soils at 0.075 ppm in triplicate), 107 (89%) of those spiked in soil containing 4.0% organic matter showed recoveries of 70-130%, as did 98 (82%) of those spiked in soil containing 5.2% organic matter. At a signal-to-noise ratio of 5 for all pesticides except chlorothalonil in soil containing 5.2% organic matter, limits of detection ranged from less than or equal 1 to 15 ng/g.