Describes two methods for determining certain organic nitrogen and phosphorous compounds in waters by gas chromatography, which may be extended to include additional substances, provided the methods are validated for each individual case.

This International Standard specifies two methods for the determination of certain organic nitrogen and phosphorus compounds in waters by gas chromatography (see Table 1). The methods may be extended to include additional substances, provided the methods are validated for each individual case. Clause 3 describes the liquid/liquid extraction method, which is applicable to samples of drinking waters, ground waters, surface waters and waste waters containing up to 0,05 g/l of suspended solids. In the presence of organic matter, suspended matter and colloids, interferences are more numerous and consequently the detection limits of this method can be higher. NOTE Because of the very low concentrations normally present in the waters, the problem of contamination is extremely important. The lower the level measured, the more precautions have to be observed. Clause 4 describes the liquid/solid extraction method which is applicable to samples of ground water, surface water and drinking water containing mass concentrations of about ≥ 0,05 μg/l. Interferences occurring with the examination of some types of surface water can prevent the application of this method. Detection limits are given for information in annex A. NOTE When applying this International Standard, the guide on analytical quality control for water analysis (see ISO/TR 13530) should be followed. Table 1 Organic nitrogen and phosphorus compounds analysed by these methods Name Molecular formula Molar mass CAS No.a Atrazine C8H14ClN5 215,7 001912-24-9 Cyanazine C9H13ClN6 240,7 021725-46-2 Metazachlor C14H16ClN3O 277,8 067129-08-2 Parathion (ethyl) C10H14NO5PS 291,3 00056-38-2 Parathion (methyl) C8H10NO5PS 263,2 298-00-0 Pendimethalin C13H19N3O4 281,3 040487-42-1 Propazine C9H16ClN5 229,7 000139-40-2 Sebuthylazine C9H16ClN5 229,7 007286-69-3 Simazine C7H12ClN5 201,7 000122-34-9 Terbuthylazine C9H16ClN5 229,7 005915-41-3 Trifluralin C13H16F3N3O4 335,3 001582-09-8 Vinclozolin C12H9Cl2NO3 286,1 050471-44-8 a Chemical Abstracts Registry Number. 2