EXTRACTION EFFICIENCIES FOR PESTICIDES IN CROPS .1. [CARBARYL-C-14 EXTRACTION FROM MUSTARD GREENS AND RADISHES

14C-labeled carbaryl (1-naphthyl N-methylcarbamate) suspended in a commercial carbaryl formulation was sprayed on mustard greens and radishes. At three intervals, postapplication, the crops were extracted using methanol, acetonitrile, or acetone. Crops were either blended and leached or repetitively blended followed by Soxhlet extraction. Essentially all of the extractable radioactivity was removed by blending. The 14C was more difficult to extract from radishes than from mustard greens and with increasing time after application. For mustard greens 92, 83, and 77% of the 14C at harvest was extractable at 3, 7, and 14 days, respectively; for radishes 91, 76, and 58% was extractable at the same intervals. Methanol was generally the best solvent and the blend-Soxhlet process was superior to the blend-leach process. Thin-layer chromatography of the organic soluble extracts indicated that the majority of 14C was carbaryl. Acid hydrolysis of the extracted tissues released 40-50% of the residual 14C. © 1978, American Chemical Society. All rights reserved.