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.

Analytical method for hydrophilic polar environmental pollutants was studied. Among these pollutants, the halogenated lower carboxylates were the target compounds of this investigation. A novel but simple derivatization method necessary for sample preparation for instrumental analysis was developed. The new derivatization method for the carboxylates is not a conventional chemical reaction in non-aqueous solvent following isolation from the environmental samples but rather, a direct aqueous reaction ; direct conversion of the carboxylates to amides using a carbodiimide in dilute aqueous solution. Halogenoanilines were selectively used with dicyclohexylcarbodiimide (DCC) under acidic conditions at room temperature to form the anilide derivatives. Moreover, this reaction proceeds while mixing the sample water, DCC, a halogenoaniline, and small volume of extracting solvent. Thus, for the first time, simultaneous derivatization of the carboxylates and extraction of the products into solvent was achieved. Based on the results, simple and practical determination methods by gas chromatography were developed for traces of these carboxylates in environmental samples and the proposed methods were applied to some real samples. Such analytical derivatization methods for carboxylates are useful and noteworthy because they can form C-N bonds in aqueous media under mild conditions with carbodiimides and N atoms of amino and other compounds.

Many complaints have been made about bad smelling and tasting food and accidents resulting in the death of animals in Nagano Prefecture. The method of headspace SPME-GC/MS has been found very effective as a screening method to investigate the cause of these complaints and accidents. This method is characterized mainly in that the operation is simple without using any solvents for extraction, causing no environmental pollution; the extraction may be carried out in a short time with a small quantity of sample in low concentration, preventing reagent contamination, the whole extract may be injected, leading to high sensitivity, and the fiber may be used repeatedly, making the analytical cost inexpensive. This paper describes representative examples of cases in which the relevant causes have been solved.

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.

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).

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.