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  • 1 Tokyo Metropolitan University Department of Chemistry, Graduate School of Science 1-1 Minami-Ohsawa Hachioji, Tokyo 192-0397 Japan
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Radiochemical neutron activation analysis (RNAA) was applied to geochemical and cosmochemical samples to determine trace amounts of Mo and W. To determine the Mo concentration by NAA accurately, the contribution of the fission products of U should be corrected. For that reason, we developed a simple and effective method, where a contribution of fissiogenic 99Mo was estimated by monitoring the ratio of uranium fission-product 99Mo to 133I. Mo concentrations corrected for fission with the W concentrations were consistent with the literature values, showing that 133I was found to be an effective monitor for fission correction. Detection limits are estimated to be 10 ppb for Mo and W and 30 ppb for U under the present experimental conditions.