1.1 Field of application This International Standard specifies a method for the determination of dissolved sodium by flame atomic absorption spectrometry (AAS). It is intended for the analysis of raw and drinking water. The method is applicable to water samples with a mass concentration of sodium in the range from 5 mg/l to 50 mg/l. This range can be extended to lower or higher limits if dilution factors are chosen which are different from the factor specified in clause 8. 1.2 Interferences The ions normally present in raw and drinking waters do not interfere with the determination of sodium by atomic absorption spectrometry.