Analysis of Benzene Series in Groundwater by Gas Chromatography with Needle trap-Headspace Sampling

A method for the determination of 7 benzene series in groundwater samples by gas chromatography with Needle trap-headspace sampling was developed, which represents the integrated features of on-site sampling, solvent-free extracting and thermal desorption. The experiment conditions such as extraction temperature, sample-equilibration time, pump volume of syringe plunger, additive amount of salt and sample storage time were tested and optimized. The detection limits of the method for 7 benzene series were 0.06~0.09 μg/L and the recoveries were 84.27%~115.03% with precision of lower than 7%RSD(n＝7), which is consistent with relevant criteria of US EPA. The method is suitable for the determination of these benzene series in groundwater samples.