【国外标准】 Standard Guide for the Determination of Technetium-99 in Soil

5.1 This guide offers several options for the determination of 99Tc in soil samples. Sample sizes of up to 200 g are possible, depending on the method chosen to extract Tc from the soil matrix. It is up to the user to determine if it is appropriate for the intended use of the final data.1.1 This guide is intended to serve as a reference for laboratories wishing to perform 99Tc analyses in soil. Several options are given for selection of a tracer and for the method of extracting the Tc from the soil matrix. Separation of Tc from the sample matrix is performed using an extraction chromatography resin. Options are then given for the determination of the 99Tc activity in the original sample. It is up to the user to determine which options are appropriate for use, and to generate acceptance data to support the chosen procedure.1.2 Due to the various extraction methods available, various tracers used, variable detection methods used, and lack of certified reference materials for 99Tc in soil, there is insufficient data to support a single method written as a standard method.1.3 The values stated in SI units are to be regarded as standard, except where the non-SI unit of molar, M, is used for the concentration of chemicals and reagents. The values given in parentheses after SI units are provided for information only and are not considered standard.1.4 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.1.5 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.