A method by GC/MS has been established for the determination of dimethenamid and cyhalofop-butyl in agricaltural products. Dimethenamid and cyhalofop-butyl were extracted with acetone, concentrated, and re - extracted with n - hexane. The extracts were cleaned up acetonitrile partitioning and florisil column, then determined by GC/MS-SIM. This method was featured of recovery over 75% and it's C.V. below 6%. The detection limits for dimetenamid and cyharofop-butyl were 0.001 micro g/g and 0.002 micro g/g, respectively.

An investigation was made to find analytical method for anilazine and propazine remaining in agricultural products. Since anilazine was found to be decomposed enzymatically when applied on cabbage, radish, etc., phosphoric acid was added to the sample to suppress the enzymatic activity before subjecting the sample to an extraction with acetone. The extract was re-extracted into n-hexane, cleaned up with a Florisil column, and finally subjected to a determination with ECD-GC. Propazine was found to be insusceptable to any enzymatic decomposition, but it was subjected to the same acetone extraction and n-hexane re-extraction as with anilazine, separated from anilazine with a Florisil column, and subjected to a determination with NPD-GC. The detection limits of these methods are 0.01 micro g/g for both anilazine and propazine. The addition-recovery experiments conducted resulted in recoveries of over 79 and 82% with coefficient of variation of less than 5.6 and 5.5% for alilazine and propazine, respectively (n=5). The present methods were applied to actual agricultural products, with neither anilazine nor propazine detected (n=22).