AUTOMATED PROCEDURE FOR EXTRACTION OF METOLACHLOR FROM SOIL

Methods for extraction of ethylphenyl)-N-(2-methoxy-1-methylethyl)acet amide] from soil are tedious and time-consuming. Existing robotic stat ions were adapted to provide an automated multistep method of metolach lor extraction from soil. The method was examined using a fine-loamy, mixed Udic Haploboroll. Duration of equilibration (0-4 h), initial soi l pH (5.0-7.1), temperature of evaporation (24, 35, and 50 degrees C), and gas used for perfusion (air or N-2) were examined. Extraction eff iciency was unaffected by duration of equilibration or initial soil pH . A temperature by perfusion gas interaction affected percent recovery . At 24 degrees C, N-2 provided a small but measurable advantage in re covery, 71.1-74.2%. At 35 degrees C, a clear advantage in recovery, 50 .5-69.8%, was obtained using compressed air. At 50 degrees C, recovery , which averaged only about 38%, was unaffected by perfusion gas. Rela tive recovery was unaffected by incubation time in 90% methanol over a 4-h range. Relative to the current extraction method, the serialized robotic method increased sample output by 267%. Relative costs of extr action were also compared. Hazardous waste generation was decreased by about 67%, and reagent cost was decreased by > 75% using the robotic method.