In many drinking water treatment plants. the chlorination process is one of the main techniques used for the disinfection of water. This disinfecting treatment leads to the formation of trihalomethanes (THMs) such as chloroform, dichlorobromomethane, chlorodibromomethane and bromoform. In this study. head space-solid-phase microextraction (HS-SPME, 85 mum carboxen/polydimethylsiloxane fiber) technique was applied for the analysis of THMs in drinking water. The effects, of experimental parameters such as kinds of SPME fiber, the volume ratio of sample to headspace. the addition of salts, magnetic stirring, extraction temperature. extraction time and desorption time on the analysis were investigated. Analytical parameters such as linearity. repeatability and limit of detection were also evaluated. The results of THMs from the survey of Seongnam (Korea) drinking water samples showed that the highest total trihalomethane and chloroform were 24.03 and 13.34 mug/l, which were well within the Korean drinking water quality standard of 100 and 80 mug/l, respectively. (C) 2002 Elsevier Science Ltd. All rights reserved.