Analysis of acetochlor and butachlor residues in environmental samples.

The residues of acetochlor and butachlor in environmental samples (wat er, soil and crop) were determined with LC-UV detector after the samples were ex tra with ultrasonic wave using acetone-water (V/V,80/20) and the extracts were p artitioned between petroleum ether and water. The spiked recoveries for acetochl or and butachlor were 87.7%~90.1% and 87.5%~90.7% respectively; and the relative standard deviations (R.S.D.) of recoveries were 2.4%~6.3% and 4.3%~7.1% respect ively. The lowest detection concentration for acetochlor and butachlor was 0.015 and 0.037 mg/kg respectively in soil and crop samples, and 0.004 and 0.009 mg/L respectively in water samples. Acetochlor and butachlor were not detected in ri ver water from Jingmi Canal on the north of Beijing. One month after acetochlor and butachlor were applied, their residues in soil were approaching to or lower than the lowest detection limit.