EFFECT OF EXTRACTION SYSTEMS ON CLOMAZONE RECOVERY FROM AGED SOIL SAMPLES

Seven extraction methods were examined to determine which one provided a simple, efficient clomazone extraction from aged soil. The method s elected involved adding 80 mt acetonitrile to moist soil and shaking f or 16 h. The extract was filtered, and an additional 80 mt acetonitril e was added, equilibrated for 1 h, and filtered. Filtrates were combin ed and concentrated with a rotary evaporator. Clomazone concentrations were then determined by reversed-phase liquid chromatography with UV detection at 220 nm. Recovery with this method was equal to a 16 h + 1 h extraction with methanol, but acetonitrile was selected as extracti on solvent because of its ease of removal with a rotary evaporator. Th e recovery from fortified soil samples was >80%, and a conservative lo wer limit of detection was 40 ng/g soil.