本文件规定了通过电感耦合等离子体质谱（ICP-MS）（239Pu、240Pu、241Pu和237Np）测定水中钚和镎同位素浓度的方法。获得的浓度可以转换为不同同位素的活性浓度[9]。 由于其相对较短的半衰期和238U等压干扰，238Pu很难用这种方法测量。为了量化这种同位素，可以使用其他技术（带有碰撞反应池的ICP-MS、带有碰撞反应池的ICP-MS/MS或化学分离）。目前使用的是ISO 13167[10]中所述的阿尔法光谱测量[11]。 该方法适用于含盐量小于1 g·l？1的所有类型的水。稀释样品可获得与制剂和测量组件相容的盐水负荷和活性浓度的溶液。 测定溶解核素时，需要0.45μm的过滤。样品总是需要酸化和化学分离。 定量限取决于化学分离和测量设备的性能。 该方法包括在[12][13]左右的放射性浓度范围内测量水中的同位素: -239Pu、240Pu和237Np为1mBq·l？1至5Bq·l？1； -241Pu为1bq·l-1至5bq·l-1。 在这两种情况下，如果在化学分离之前进行稀释，则可以测量活性浓度高于5 Bq·l？1的样品。 在至少1000的预浓缩步骤后，可以测量241Pu。

This document specifies methods used to determine the concentration of plutonium and neptunium isotopes in water by inductively coupled plasma mass spectrometry (ICP-MS) (239Pu, 240Pu, 241Pu and 237Np). The concentrations obtained can be converted into activity concentrations of the different isotopes[9]. Due to its relatively short half-life and 238U isobaric interference, 238Pu can hardly be measured by this method. To quantify this isotope, other techniques can be used (ICP-MS with collision-reaction cell, ICP-MS/MS with collision-reaction cell or chemical separation). Alpha spectrometry measurement, as described in ISO 13167[10], is currently used[11]. This method is applicable to all types of water having a saline load less than 1 g·l？1. A dilution of the sample is possible to obtain a solution having a saline load and activity concentrations compatible with the preparation and the measurement assembly. A filtration at 0,45 μm is needed for determination of dissolved nuclides. Acidification and chemical separation of the sample are always needed. The limit of quantification depends on the chemical separation and the performance of the measurement device. This method covers the measurement of those isotopes in water in activity concentrations between around[12][13]: — 1 mBq·l？1 to 5 Bq·l？1 for 239Pu, 240Pu and 237Np; — 1 Bq·l？1 to 5 Bq·l？1 for 241Pu. In both cases, samples with higher activity concentrations than 5 Bq·l？1 can be measured if a dilution is performed before the chemical separation. It is possible to measure 241Pu following a pre-concentration step of at least 1 000.