Separation of 9Be and cosmogenic 10Be from environmental materials and SIMS isotope dilution analysis

A recently developed high-resolution secondary ion mass spectrometer (SIMS) allows direct determination of the ratio of cosmogenic 10Be to stable 9Be. In this paper a new method for high-purity separation of nanogram amounts of Be from environmental materials, such as silicates, oxides, or water is described. The separation employs a flexible combination of ion exchange columns with optional hydroxide coprecipitation. The natural 10Be9Be ratio is measured directly by multi-collector SIMS. Secondly, an isotope dilution method for determination of 9Be concentrations is described. This approach uses a 10Be-enriched solution as tracer, and offers considerable advantages over methods, of which concentration results are sensitive to matrix effects (ICP-MS, AAS). We illustrate the methods with examples from oceanic FeMn-oxide sediments.