This International Standard specifies the conditions for determining the activity concentration of 14C in samples of environmental water or water containing 14C using a liquid scintillation counter. The method is applicable to the analysis of all organic water-soluble molecules that are well mixed in the scintillation cocktail. It cannot be used on micelles or "large" particles (lipids, fulvic or humic acids, etc.) that are not carefully mixed in the scintillation cocktail and water. Here, some beta energy is lost without exciting the scintillation cocktail and the results are underestimated. This method is also not suitable for the analysis of organically bound 14C. This determination requires further chemical processing (such as chemical oxidation or combustion). It is possible to measure an activity concentration of 14C below 106 Bq l-1 without sample dilution.
EN ISO 13162:2015 Referenced Document
ISO 11929:2010 Determination of the characteristic limits (decision threshold, detection limit and limits of the confidence interval) for measurements of ionizing radiation - Fundamentals and application
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EN ISO 13162:2015 history
2021EN ISO 13162:2021 Water quality - Carbon 14 - Test method using liquid scintillation counting (ISO 13162:2021)
2015EN ISO 13162:2015 Water quality - Determination of carbon 14 activity - Liquid scintillation counting method