Rapid Determination of 226Ra in Glass Fiber Air Filters
Summary of Method
226Ra is separated from 47mm glass fiber air filters and measured by alpha spectrometry. Samples are fused with sodium hydroxide at 600°C. The fusion cake is dissolved in water, and radium is precipitated from samples with calcium carbonate. The calcium carbonate precipitate is dissolved in hydrochloric acid, and cation exchange chromatography is used to purify radium and barium from matrix ions. Barium is removed from samples using Eichrom Sr Resin. Eichrom DGA Resin is used to separate radium from other alpha emitting nuclides. Samples are prepared for alpha spectrometry by barium sulfate micro-precipitation onto Eichrom® Resolve Filters. Sample preparation, including alpha spectrometry source preparation, for batches of 12 samples can be completed by a single operator in as little as 6 hours, with 85-90% yield of Radium. Yields are traced with 225Ra(229Th) by alpha spectrometry. At least 8 hours of ingrowth time for the alpha emitting 217At daughter of 225Ra is required prior to measurement by alpha spectrometry.