FALSE RESULTS IN HEADSPACE GAS-CHROMATOGRAPHIC ANALYSIS OF TRIHALOMETHANES IN SWIMMING POOL WATER DUE TO ELEVATED HEADSPACE TEMPERATURES

The application of a headspace GC method for the determination of trih alomethanes (THMs) in water is described for the case of swimming pool water. As a consequence of chlorination, swimming pool water contains , besides THMs, many other halogenated compounds. Among these, the tri haloacetic acids may interfere with THM determination because they are decarboxylated to the related THMs at the usually applied headspace t emperatures. This disturbing effect was investigated at different temp eratures for real swimming pool water samples. It occurs down to 40-de grees-C and was found to be avoidable at a headspace temperature of 33 -degrees-C or less.