Determination of ⁹Be in geological standard samples, JA-2 and JB-2, and of ⁹Be and ¹⁰Be in a basaltic rock sample for evaluation of uncertainty involved in ¹⁰Be/⁹Be ratio measurements

抄録

We determined the concentrations of ⁹Be in JB-2 and JA-2 geological standard samples using an inductively coupled plasma mass spectrometer (ICP-MS). We determined ⁹Be abundance in standard samples of JA-2 and JB-2 as 2.26 ± 0.10 and 0.241 ± 0.010 ppm, respectively, after comparing and selecting ⁹Be concentration data obtained by the internal standard method, the standard addition method and the column separation method. In the course of comparison, we identified a problem in the internal standard method, which is usually used for abundance analyses using an ICP-MS. Repeated analyses of a basalt lava gave a standard deviation of ¹⁰Be abundance of 9% (1σ, n = 5). From the results, we estimated the uncertainty of ¹⁰Be/⁹Be ratio as 10% (1σ), considering a law of propagation of errors.