A fully automated system has been developed by our research group for the solid-phase extraction, desorption and GC/MS measurement of water samples. In the present work, the validity for the determination of simazin and thiobencarb in environmental water samples using a fully automated online SPE-GC/MS system was investigated. Calibration curves of simazin and thiobencarb demonstrated good linearity in the range of 0.30–5.0 μg L−1. The repeatability in the case of the on–line coupling system of automatic SPE with GC/MS was studied, and the relative standard deviations (RSDs) in the case of aqueous solutions of simazine and thiobencarb solutions (0.3 μg L−1) were 4.4 % and 4.5 % for seven measurements. The method was applied to the determination of simazine and thiobencarb in river and sea waters. Environmental water samples were spiked with 1.0 μg L−1 for evaluating the recovery. The recovery for the spiked amount was in the range of 96.2–107 %. The present system was considered to be satisfactorily for the determination of simazine and thiobencarb in environmental water samples.
