Analysis of some chlorinated hydrocarbons in water by headspace technique

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 sensitivity and the percent recovery i.e., equilibration time, temperature, liquid to gas phase volume ratio, injection volume and salting out with sodium chloride, sodium sulfate and calcium carbonate were studied and evaluated. The temperature of 60℃, equilibration time of 60 minutes, the liquid to gas phase volume ratio 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 analysis of the volatile chlorinated hydrocarbons in water samples. The minimum detectable level of this technique was lower than 0.50 ppb (µg/L) for all studied compounds and the percent recoveries of the chlorinated hydrocarbons were in the range of 54.22 – 90.81 % with ± 1.04 – 4.81 % RSD. The accuracy of this technique was also studied by means of internal standardization method and the percent errors were in the range of 0.31 – 6.44 % at the ppb level of concentration. Moreover, the developed technique was also applied to analyze tap water and pool water collected from six different places. Results showed that all water samples appeared to have methylene chloride and chloroform in the range of 10.22 – 448.68 and 0.22 – 31.86 ppb, respectively.