Abstract:
In this study, a headspace technique was developed for the determination of some volatile chlorinated hydrocarbons i.e, methylene chloride, chloroform, carbon tetrachloride, 1,1,1-trichloroethane and trichloroethylene in water samples. Various factors having effect on the percent recovery were studied and evaluated. The temperature of 60ํC equilibration time of 60 minutes, the liquid to gas phase volume ration of 30:30 in 60 ml serum vial, 1.50 ml of injection volume, and salting out with 13.00 g of anhydrous sodium sulfate were chosen as the optimal headspace analysis condition for the determination of the volatile chlorinated hydrocarbons in water samples. The minimum detectable level of this technique was lower than 0.50 ppb (microg./L) for all studied compounds and the percent recoveries were in the range of 62.43–89.95% with +- 2.40–4.81% RSD. The accuracy of this technique was also studied by means of internal standardization method, the percent errors were in the range of 0.31–6.4% at the ppb level of concentration. Morevover, the developed technique was also applied to analyze water samples collected in the Central Bangkok Metropolitan area. Result showed that methylene chloride and chloroform were found in the range of 15.50–214.88 and 1.05–38.98 ppb, respectively in drinking waters produced from several companies, and 33.43–49.50 and 0.78–48.32 ppb, respectively in tap water samples collected from several places.
