Determination of trihalomethanes in chlorinated sea water samples using a purge-and-trap system coupled to gas chromatography

In power stations, the cooling effluents are chlorinated to avoid excessive biofouling. Yet, this disinfecting treatment leads to the formation of hal ogenated by-products, mainly trihalomethanes. So, there is a need for preci se and accurate methods that allow trace levels determination of these comp ounds. A system that combines purge-and-trap and gas chromatography (with a n electron capture detector) was used in this study. After careful choice o f the experimental conditions, the performance of the system were evaluated . Precise and accurate determinations were obtained, allowing the determina tion of trihalomethanes in sea water samples chlorinated on site in three F rench coastal power stations. Bromoform was the predominant component forme d, while traces of dibromochloromethane, chloroform and bromodichloromethan e were also detected. (C) 2000 Elsevier Science B.V. All rights reserved.