Abstract
The determination of benzene, toluene, p-xylene, tetrachloroethene, chlorobenzene, and dibromomethane in water by headspace analysis combined with gas chromatography-mass spectrometry (HS-GC-MS) has been investigated. An optimization strategy for the analysis of the six volatile organic compounds (VOCs) is presented with the experimental design and response surface methodology aid. Thermostatting time, temperature, and salt quantity were optimized by using a central composite design, and quadratic models relating peak areas to the three factors were built. The mathematical models were tested on a number of simulated data set and had a coefficient of R2>0.98. The factor effects were visualized as three-dimensional response surfaces and contour plots. The optimal conditions were achieved in 36.8 min, at 90 degrees C, and with 6 g of NaCl. The method showed a good agreement between the experimental data and predictive values throughout the studied parameter space, and was suitable for optimization studies of the VOCs in water by the HS-GC-MS method.