The development of headspace technique for analysis of some semivolatile organic compounds in water

Abstract

A headspace technique has been developed for the determination of semivolatile organic compounds i.e., ethylbenzene, chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene and 1,4-dichlorobenzene in water samples. The various factors having the effect on sensitivity and percent recovery, i.e., equilibration time, temperature, phase ratio, injection volume, and salting out with NaCl and anhydrous Na₂SO₄ were studied and evaluated. The temperature of 45.0ºC, equilibration time of 30 min, the liquid to gas phase ratio of 25:35, 2.00 mL of injection volume, and salting out with 10.00 g of anhydrous Na₂SO₄ were chosen as an optimum headspace analysis condition for the analysis of the semivolatile organic compounds in water samples. The detection limit of this technique was less than 1.00 ppb. (μg/L) for all studied compounds and the percent recoveries of semivolatile organic compounds were in the ranges of 53.30-91.51% with 0.77-10.62 % %RSD. The accuracy of this technique was also studied by two different methods, i.e., external standardization and standard addition methods and the % errors found were less than 11.63 % at the ppb level of concentration. In addition, the wastewater samples collected from three pools in Chulalongkorn University were analyzed and one of them collected from the pool behind Chemistry Building 2 seemed to have chlorobenzene and its content in the water sample was 0.60 ppb.