2016 Volume 64 Issue 6 Pages 225-235
Several important developments in the mass spectrometry techniques have been made in the last decade, including higher ionization efficiency, higher transmission efficiency, and faster mass scan capability, as well as a wide dynamic range for the ion collection. Especially, dynamic range and stability of the ion detection system is a still key issue for both elemental and isotopic analyses of geochemical and biochemical samples. Extremely high sensitivity can be achieved by the electron multiplier technique, but there still remains a problem associated with long- to medium-term gain stability. Time changes in gain of the EM was the major reason why multiple collection using the EMs was not developed. In strike contrast, it is widely recognized that Daly ion collector can provide higher gain stability and a wider dynamic range for the ion detection. In this study, long-term and medium-term stability, together with the dynamic range of the Daly ion collector were rigorously tested. The result showed that both linearity and stability was significantly better than the EMs. The resulting analytical capabilities and basic performance revealed that the Daly detectors can provide much more precise and accurate elemental and isotope ratio data for trace-elements in both the geochemical and biological samples. Details of the system configuration and analysis capability for the isotope ratio measurements will be described in this paper.
