Determination of volatile organic compounds in drinking and environmental waters

Volatile organic compounds (VOCs) are of prime concern due to their toxicity and persistence in the environment. We focus on sample-preparation methods, instruments used and concentrations reported in the determination of VOCs in aquatic matrices (e.g., seawater, river water, groundwater and drinking water). We pay special attention to sample-enrichment methods and mention the application of different detectors with respective sensitivities. We note that, among the sample-pre-concentration methods, purge-and-trap and solid-phase microextraction were the most chosen methods, which enabled excellent recoveries for a wide range of VOCs. Among the detectors, the mass-selective detector was unchallenged, due to the remarkable sensitivity and detection based on mass. Tandem mass spectrometry is still emerging for determining VOCs, since not many papers have been published on it. The compounds detected most were the halogenated volatiles [e.g., dichloroethane, trichloroethane, bromodichloromethane and dibromochloromethane (DBCM)], followed by benzene, toluene, ethylbenzene and xylene (BTEX). Trihalomethanes have also been reported as a result of water-disinfection byproducts. Finally, the VOC levels detected most were the trihalo-alkanes (trichloromethane: 1900 ng/L in estuary surface water; tribromomethane: 147-762 ng/L in drinking water; and, DBCM:92-399 ng/L in drinking water), and among BTEX were benzene (3.9-141.7 ng/L in seawater) and xylene (4.3-332 ng/L in seawater). We also note the need for quality assurance and mention the European Union Directive regarding VOCs. (C) 2011 Elsevier Ltd. All rights reserved.