This International Standard specifies a method for the determination of phthalates in water after solid phase extraction and gas chromatography/mass spectrometry. This method is applicable to the determination of phthalates (see Table 1) in ground water, surface water, wastewater and drinking water in mass concentrations ranging from above 0,02 µg/l up to 0,150 µg/l, depending on the individual substance and the value of the blank. The applicability of this method to other phthalates not specified in Table 1 is not excluded, but it is necessary to determine its applicability in each case (see Annex A for the list of phthalates). General remarks concerning the recovery and use of internal standards is given in Annex B.