Determination of simazine, terbuthylazine, and their dealkylated chlorotriazine metabolites in soil using sonication microextraction and gas chromatography

A rapid analytical method is proposed for the determination of simazine, terbuthylazine, and their chloro dealkylated metabolites (simazine-desethyl, simazine-bisdesethyl, and terbuthylazine-desethyl) in soil. A sonication micromethod is presented for the extraction of -triazine herbicides and their metabolites. Final determination is by gas chromatography (GC) with nitrogen-phosphorus detection. The identity of all compounds was confirmed by GC with mass selective detection in the selected-ion monitoring mode. All chromatograms were very clean, without interfering peaks, and no cleanup was needed. The limits of detection were 1 pg for simazine-bisdesethyl; 5 pg for simazine, terbuthylazine, and terbuthylazine-desethyl; and 10 pg for simazine-desethyl. The limits of quantitation were 1, 5, and 10 ppb, respectively. Mean recoveries from fortified soils ranged from 76% for simazine-bisdesethyl to 102% for simazine-desethyl, with relative standard deviations of 3-6%.