The method specifies a general method for the determination of volatile organic compounds (VOC´s) in water by purge and trap isolation and gas chromatography (GC). The annexes A, B, and C show examples of analytes that may be determined by this standard. They range from difluorodichloromethane (F-12) up to trichlorobenzene, including all non polar organic compounds of intermediate volatility. Detection is preferably carried out by mass spectrometry in the electron impact mode (EI), but other detectors may be applied as well. The limit of detection largely depends on the detector in use and the operational parameters. Typically detection limits as low as 10 ng/l can be achieved. The working range typically is up to 100 µg/l. The standard can be applied to drinking water, ground water, surface water, sea water and to (diluted) waste water.