An analytical method for an insecticide Fipronil and its metabolite MB 46513 remaining in agricaitunil products has been established which uses GC-ECD and GC/MS for their determination and continuation, respectively. In this method, target compounds are extracted with acetone from agricultural products, concentated, and finally re-extracted with n-hexane. When the sample contains lipid in large quantity, it is first delipidated by partition with acetonitrile, cleaned up with Florisil column, and finally determined by GC-ECD. In the case of vegetables and fruits, which contain lipids in small quantity, the sample is cleaned up with a Florisil column and determined by GOECD. The detection limit of this method is 0.001 micro g/g for both of these kind of samples, the recovery of Fipronil is over 85%, and the C. V. of the recovery is less than 7%. For MB-46513. the recovery is over 63% and its C. V. is less than 9%. This method was applied to 17kinds of agricultural products and no Fipronil and MB46513 were detected.

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.

A method by GC/MS has been established for the determination of Etoxazole in agricaltural products. Etoxazole was decomposed by acid contained in citrus fruits, but this decomposition could be prevented by addition of sodium acetate solution and extraction above pH 4. In the present method, the Etoxazole in agricultural products was extracted with acetone above pH 4, concentrated, and reextracted with n-hexane. After partition with acetonitrile followed by chromatographic clean-up with Florisil, the sample was subjected to GC/MS. The present method is excellent in sensitivity and has a detection limit of 0.002 micro g/g, and thus is about 10 times as sensitive as that of GC-NPD. The recovery by the present method is over 85% except for tea, the C.V. of recovery is less than 8%, and the method is applicable to actual samples.

A method by GC/MS has been established for the determination of Pyrimidifen in agricaltural products. The Pyrimidifen in agricultural products is extracted with acetone, concentrated, and extracted with n-hexane. The solution is cleaned up with a Florisil column and subjected to a determination by GC/MS using p-terphenyl-d14 as the internal standard. This method is featured by the recovery over 80 % with its C .V. below 8 % and the detection limit 1 micro g/kg. This method, excellent in sensitivity and selectivity, is useful as a rutine analytical method for agricultural products.