Abstract
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 207Pb/206Pb and 208Pb/206Pb 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.
