Determination of residues of alachlor and its metabolite in corn, soybeans, and potatoes as heptafluorobutyryl-2,6-diethylaniline.

Alachlor [2-chloro-2',6'-diethyl-N-(methoxymethyl)acetanilide] was determined by hydrolysis to 2,6-diethylaniline with 6N HCl and quantitation of the heptafluorobutyryl derivative by gas chromatography with electron capture detection. 2,6-Diethylaniline was isolated from the hydrolysate by steam distillation, derivatized with heptafluorobutyric anhydride, and the derivative was purified by chromatography on silicic acid with 60% toluene in hexane as eluant. Recoveries from potatoes, soybeans, and corn spiked at levels from 3 to 26 ppb averaged 81, 90, and 96% respectively.