水质 - 钚和ium - 使用ICP-MS的测试方法

[中文适用范围]： 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成不同同位素的活度浓度[9]。 由于238Pu的半衰期较短，且存在238U同量异位素的干扰，因此该方法很难测量238Pu。 为了量化该同位素，可以使用其他技术（带碰撞反应池的 ICP-MS、带碰撞反应池的 ICP-MS/MS 或化学分离）。 目前使用的是 ISO 13167[10] 中描述的 Alpha 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。 样品的稀释可以获得具有与制剂和测量组件相容的盐水负载和活性浓度的溶液。 测定溶解的核素需要 0.45 μm 的过滤。 始终需要对样品进行酸化和化学分离。 定量限度取决于化学分离和测量设备的性能。 该方法涵盖了水中同位素活度浓度在[12][13]之间的测量： ——239Pu、240Pu 和 237Np 为 1 mBq·l−1 至 5 Bq·l−1； ——241Pu 为 1 Bq·l−1 至 5 Bq·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。 经过至少 1000 的预浓缩步骤后，可以测量 241Pu。 [外文原描述]： 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.