This standard describes the gas chromatographic determination of 19 chlorophenols in drinking water, groundwater, rainwater, waste water, sea water and surface water. This standard describes an acetylation followed by liquid/liquid extraction and determination by gas chromatography and electron capture detection or mass selective detection. The method is validated for drinking water, surface water and waste water, but may be used for all above mentioned types of water. With this method chlorphenols can be determined over a range of concentrations from 0,1 my g/l to 1 mg/l, depending on the quantity of sample used and the component sensivity (level of chlori