Determination of Four Volatile Halohydrocarbons in Water by Purge and Trap-Gas Chromatography-Mass

A sensitive and fast analytical method using purge-and-trap (P&T) on-line coupling with gas chromatography was developed for the determination of four trace volatile halohydrocarbons including methylene, chloroform, carbon tetrachloride and trichloroethylene in water. The analytes were purged for 10min from the sample by high purity nitrogen and preconcentrated in the cooled trap at -80 degC . The halohydrocarbons were separated with an gas chromatograph by a suitable temperature program and detected by means of a mass spectrometer using selected ion monitoring (SIM). The detection limits were found to be in the range of 0.0008 to 0.02mug/L, the relative deviations ranged from 1.9% to 5.4%, the recovery ratios ranged were 89% to 104%, The linearity ranges of 4 compounds were in the range of 0.001 to 50mug/L, with correlation coefficients from 0.9991 to 0.9997. The method is fast, sensitive, simple. It has better accuracy and precision in determination of these halohydrocarbons in water compared with the traditional method.