| Popis: |
In this paper, an ICP coupled with a three dimensional quadrupole mass spectrometer (ICP-3DQMS) was evaluated for lead isotopic measurements. The 3DQMS is a type of an ion trap mass spectrometer. These days, ICP coupled with a quadrupole mass spectrometer (ICP-QMS) is widely used for its advantages of high sensitivities and capability of isotopic measurements. However, the obtained precision (％RSD) of the isotopic measurements is limited to about 0.3％, because several isotopes are detected sequentially. On the other hand, because 3DQMS can trap several isotopes simultaneously, a precision of less than 0.1％ (ca. 0.08％) could be achieved for 207 Pb/ 206 Pb and 208 Pb/ 206 Pb in this study. One drawback of 3DQMS is that there is a limitation on the number of total ions, that can be trapped. It was found that the value of [trapping time (ms)×concentration (ng/ml)] influences the accuracy and precision of isotopic measurements. |
