DIN EN ISO 9698:2015-12

This International Standard specifies a method by liquid scintillation counting for the determination of tritium activity concentration in samples of marine waters, surface waters, ground waters, rain waters, drinking waters or of titrated water ([(³H]H₂O) in effluents. The choice of the analytical procedure, either with or without distillation of the water sample prior to determination, depends on the aim of the measurement and the sample characteristics. Direct measurement of a raw water sample using liquid scintillation counting has to consider the potential presence of other beta emitter radionuclides. To avoid interference with these radionuclides when they are detected, the quantification of tritium will be performed following the sample treatment by distillation. Three distillation procedures are described in Annexes B, D and E. This method is not applicable to the analysis of organically bound tritium. This determination requires additional chemical processing of the sample (such as chemical oxidation or combustion). With suitable technical conditions, the detection limit is as low as 10⁶ Bq·l-1. Tritium activity concentrations below 10⁶ Bq·l-1 can be determined without any sample dilution. A prior enrichment step can significantly lower the limit of detection. The text of ISO 9698:2010 has been prepared by Technical Committee ISO/TC 147 "Water quality" of the International Organization of Standardization (ISO) and been adopted as EN ISO 9698:2015 by Technical Committee CEN/TC 230 "Water Analysis", the secretariat of which is held by DIN (Germany). The responsible German committee is NA 119-01-03 AA "Wasseruntersuchung" ("Water examination") at DIN Standards Committee Water Practice(NAW).