Combining membrane extraction with mobile gas chromatography for the field analysis of volatile organic compounds in contaminated waters

A mobile gas chromatographic device (Airmobtx HC 1000 monitor manufactured by Airmotec, Germany), originally designed for the analysis of benzene, toluene, ethylbenzene and xylenes (BTEX) in air, was connected to a flow cell for dynamic membrane extraction. Volatile organic compounds (VOCs) diffuse out of a water stream through a hollow fibre, are enriched onto sorption tubes integrated in the mobile device, and are then thermally desorbed and analysed by gas chromatography-flame ionisation detection. Battery operation of the device enables continuous on-site analysis of VOCs. Influences of the water flow-rate on system response and memory effects were investigated. The linear range of the method depends on the flow-rate of the water sample and did not exceed two orders of magnitude. The detection-limits for trichloroethene, chlorobenzene and the BTEX Compounds were found to be between 0.1 and 1.0 mug/l using a water flow-rate of 30 ml/min. Dynamic membrane extraction combined with the mobile gas chromatographic device was used for the on-site analysis of contaminated waters in the area of Leipzig. (C) 2001 Elsevier Science B.V. All rights reserved.