1.1 本试验方法涵盖了硝酸稀释后通过电感耦合等离子体质谱（ICP-MS）测定尿液中的铀。该方法分两部分介绍。A部分描述了一种不区分铀同位素的测定尿中总铀的方法。B部分描述了一种确定 235 你到 238 A部分已显示含有数据用户认为重要的铀水平的样品中的U（浓缩）。部分B中的测量可以与部分A中的测量组合以计算A。 235 U浓度。浓缩测量又可用于估计微量铀同位素的水平，特别是 234 U，这对于计算暴露于铀的个体所接受的内部辐射剂量是重要的。次要同位素浓度的估计和内剂量的计算不构成本标准的一部分。 1.2 单位- 以SI单位表示的值将被视为标准值。本标准不包括其他计量单位。 1.3 本标准并不旨在解决与其使用相关的所有安全性问题（如果有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践并确定法规限制的适用性。 1.4 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。======意义和用途====== 5.1 作为核设施工作人员生物测定计划的一部分进行内部剂量评估是核工业中的常见做法。对于可能接触浓缩铀的工人的间接生物测定，则 235 除总铀同位素外，还必须测量铀浓度，以便对铀浓缩进行估计，用于剂量评估。 5.2 如果在样品中检测到显著的铀含量，浓缩测量在追踪铀暴露来源方面也可能是有价值的。 5.3 现代四极杆ICP-MS应能够提供接近本测试方法中要求保护的性能特征；然而，较旧的型号或性能随着时间的推移而下降的型号可能无法做到这一点。用户有责任验证其设备的性能。

1.1 This test method covers the determination of uranium in urine by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) after dilution in nitric acid. The method is presented in two parts. Part A describes a method for determination of total uranium in urine that does not distinguish between uranium isotopes. Part B describes a method that determines the ratio of 235 U to 238 U (the enrichment) in samples that Part A has shown to contain levels of uranium that the user of the data considers to be significant. The measurement in Part B may be combined with the measurement in Part A to calculate a 235 U concentration. The enrichment measurement may in turn be used to estimate levels of minor uranium isotopes, in particular 234 U, that are important for calculating the internal radiation dose received by an individual exposed to uranium. The estimation of minor isotope concentrations and the calculation of internal dose does not form part of this standard. 1.2 Units— The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 It is common practice within the nuclear industry for internal dose assessment to be made as part of a bioassay program for nuclear facility workers. For indirect bioassay of workers that may be exposed to uranium at enrichments that may differ from natural then the 235 U concentration must be measured in addition to the total uranium isotopes so that an estimate of uranium enrichment may be made for use in the dose assessment. 5.2 The enrichment measurement may also be of value in tracing the source of uranium exposure should significant uranium levels be detected in a sample. 5.3 A modern, quadrupole ICP-MS should be capable of delivering performance characteristics close to those claimed in this test method; however, older models or those where performance has deteriorated over time may be unable to do so. It is the responsibility of the user to validate the performance of their equipment.