A two-phase column was developed, allowing direct headspace sampling of volatile chlorinated aliphatic compounds, including trichloroethylene, cis- and trans-1,2-dichloroethylene and vinyl chloride. Propane, methane and CO 2 were sampled in the same fashion. A comparison of two solid support matrices (crushed glass and anthracite coal) was performed. > 97 ± 2% of the trichloroethylene added to control reactors was still present following 12 days of operation. The bioreactor consisted of an expanded-bed column containing 70 g of 60 80 - mesh substratum. The liquid phase was recirculated through the expanded-bed column into a gas-recharge column fitted with a headspace sampling port which allowed direct sampling and subsequent quantification by gas-chromatography techniques.