本文件规定了用电感耦合等离子体质谱法（ICP-MS）测定所有类型水中99Tc的方法。本方法适用于供应\/饮用水、雨水、地表水、地下水以及冷却水、工业水、生活污水、工业废水等经适当取样、处理和试样制备后的试样。必须对试样进行过滤。检测限取决于样品体积和使用的仪器。本文件所描述的方法，使用目前可用的ICP-MS，检测限约为0.2ng·kg·1～0,5ng·kg- 1（0,1bq·kg- 1～0.3bq·kg- 1），远低于WHO饮用水安全饮用水标准（100 Bq·L·1）〔3〕。本文件提供的方法不用于测定99Tc的超痕量。本文件中的质量浓度值用样品质量单位而不是样品体积单位表示，因为在类似标准中通常是这样。原因是99Tc是在淡水或海水等不同基质类型中测得的，其密度有显著差异。通过测量样品体积，可以很容易地将质量浓度值转换成样品体积单位。但是，它增加了质量浓度结果的不确定性。本文件中描述的方法适用于紧急情况，但如果99mTc的存在量可能导致干扰，则不适用。该方法不涉及悬浮物吸附Tc的分析。用户有责任确保本试验方法对所测水样的有效性。

This document specifies a method for the measurement of 99Tc in all types of water by inductively coupled plasma mass spectrometry (ICP-MS). The method is applicable to test samples of supply/drinking water, rainwater, surface and ground water, as well as cooling water, industrial water, domestic, and industrial wastewater after proper sampling and handling and test sample preparation. A filtration of the test sample is necessary. The detection limit depends on the sample volume and the instrument used. The method described in this document, using currently available ICP-MS, has a detection limit of approximately 0,2 ng·kg−1 to 0,5 ng·kg−1 (0,1 Bq·kg−1 to 0,3 Bq·kg−1), which is much lower than the WHO criteria for safe consumption of drinking water (100 Bq·l−1)[3]. The method presented in this document is not intended for the determination of ultra-trace amount of 99Tc. The mass concentration values in this document are expressed by sample mass unit instead of sample volume unit as it is usually the case in similar standards. The reason is that 99Tc is measured in various matrix types such as fresh water or sea water, which have significant differences in density. The mass concentration values can be easily converted to sample volume unit by measuring the sample volume. However, it increases the uncertainty on the mass concentration result. The method described in this document is applicable in the event of an emergency situation, but not if 99mTc is present at quantities that could cause interference. The analysis of Tc adsorbed to suspended matter is not covered by this method. It is the user's responsibility to ensure the validity of this test method for the water samples tested.