Simultaneous Determination of Volatile Halogenated Organic Compounds in Brackish Water and Seawater by Purge and Trap-Gas Chromatography/Mass Spectrometry

Simultaneous determination method for 12 volatile halogenated organic compounds (VHOCs) in brackish water and seawater has been developed, based on purge and trap-gas chromatography/mass spectrometry. The limits of detection for VHOCs were <0.04 pmol L-1 for bromomethane, iodoethane and tribromomethane, <0.13 pmol L-1 for bromochloromethane, chloroiodomethane, chlorodibromomethane and bromoiodomethane, <0.21 pmol L-1 for chloromethane, dibromomethane, bromodichloromethane, and diiodomethane and 0.67 pmol L-1 for iodomethane. Good linearities of the calibration curves for 12 VHOCs were obtained in the concentration range up to100 pmol L-1. The correlation coefficients were >0.997 for bromochloromethane, chlorodibromomethane, bromodichloromethane, bromoiodomethane and tribromomethane, >0.981 for chloromethane, iodomethane, iodoethane, chloroiodomethane and diiodomethane, 0.967 for dibromomethane and 0.923 for bromomethane. Using this developed method, the concentrations of VHOCs in brackish water, coastal seawater and open ocean seawater were measured. The coefficients of variation were approximately <20% in all samples. Thus, this simultaneous highly sensitive analysis method was valuable for determination of trace levels of VHOCs concentrations in natural water.