Determination of ethylenethiourea residues by m-trifluoromethylbenzyl derivatization [in fruit vegetables and fruits]

An improved method was developed for the determination of ethylenethiourea in agricultural products by gas-liquid chromatography with a flame photometric detector. The analytical method consists of five procedures; extraction with ethanol, conversion to the S-(m-trifluoromethylbenzyl) derivative, clean-up by washing with ethylether, N-methane-sulfonylation under basic conditions, and quantitative measurement by GLC. The resulting derivative [2-(m-trifluoromethyl) benzyl thio-1-methanesulfonyl 2-imidazoline] was stable for a month at room temperature and was detectable at a level of 0.01ppm in agricultural products. By this method, recoveries of ethylenethiourea from fifteen agricultural products fortified at a level of 0.2ppm averaged 89.0%. For the confirmation of ethylenethiourea, the use of the N-ethanesulfonylated S-(m-trifluoromethylbenzyl) derivative was preferable.