本文件规定了使用液体闪烁计数（LSC）测定所有类型水样中铁-55（55Fe）活度浓度的测试方法。使用目前可用的液体闪烁计数器，该测试方法可以测量从检测限到120？mBq？l-1。这些值可以通过计数时间在？7？200？s和？10？800？样本体积来自？0,5？l到？1,5？l.可以通过稀释样品或使用较小的样品等分试样或两者来测量较高活性浓度。 笔记？这些性能指标完全取决于各个实验室的测量制度；特别地，检测限受存在的稳定铁的量的影响。 应用范围取决于水中溶解物质的量和测量设备的性能特征（背景计数率和计数效率）。实验室有责任确保本测试方法适用于所测试的水样。

This document specifies a test method for the determination of iron-55 (⁵⁵Fe) activity concentration in samples of all types of water using liquid scintillation counting (LSC). Using currently available liquid scintillation counters, this test method can measure the ⁵⁵Fe activity concentrations in the range from the limit of detection up to 120 mBq l^-1. These values can be achieved with a counting time between 7 200 s and 10 800 s for a sample volume from 0,5 l to 1,5 l. Higher activity concentrations can be measured by either diluting the sample or using smaller sample aliquots or both. NOTE      These performance indicators are wholly dependent on the measurement regimes in individual laboratories; in particular, the detection limits are influenced by amount of stable iron present. The range of application depends on the amount of dissolved material in the water and on the performance characteristics of the measurement equipment (background count rate and counting efficiency). It is the laboratory’s responsibility to ensure the suitability of this test method for the water samples tested.