Determination of Selenium by Icp-ms and Hg-icp-ms in Coal, Fly Ashes and Sorbents Used for Flue Gas Cleaning

Selenium is an element of environmental concern which content in coal is generally lower than 2 mg g. During coal utilization for power generation this element may be emitted in gas phase or condensed in the particulate matter. To avoid the problems originated by such emissions different systems are being developed to retain selenium compounds in the system using solid sorbents. In this work, the determination of selenium in a variety of solid materials related with the use of coal for energy production was evaluated by two methods; ICP-MS and HG-ICP-MS. Coals, fly ashes and various solids used as sorbents in gas cleaning processes (kaolin, limestone, alumina, metal oxide mixtures and activated carbons), were the materials analyzed. In some of these materials, selenium can be determined with similar results by either method. However in coal, fly ashes and some activated carbons, the use of a HG-ICPMS is necessary to avoid interferences. The results obtained by both methods in samples whose selenium content ranges from μg g to mg g, are discussed. In general, good (± 2-4%) to excellent (± 1-2%) agreement between the reference and the obtained concentrations was achieved in the analysis of certified and reference samples. The