Japan Geoscience Union Meeting 2018

Presentation information

[JJ] Evening Poster

S (Solid Earth Sciences) » S-GC Geochemistry

[S-GC46] Solid Earth Geochemistry, Cosmochemistry

Tue. May 22, 2018 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall7, Makuhari Messe)

convener:Gen Shimoda(Geological Survey of Japan, AIST), Katsuhiko Suzuki(Research and Development Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology), Katsuyuki Yamashita(岡山大学大学院自然科学研究科, 共同), Akira Ishikawa(Department of Earth Science and Astronomy, The University of Tokyo)

[SGC46-P02] Stable iron isotope measurement with high resolution multiple collector inductively coupled plasma mass spectrometry (HR-MC-ICP-MS) at Geological Survey of Japan.

*Gen Shimoda1, Kosuke T Goto1, Naoko Nonose2, Ki-Cheol Shin3 (1.Geological Survey of Japan, AIST, 2.National Metrology Institute of Japan, AIST, 3.Research Institute for Humanity and Nature)

Keywords:Iron isotope, Stable isotope , MC-ICP-MS

Iron isotope ratios for standard solutions (IRMM-014 and NMIJ Fe) were measured with a Neptune Plus double-focusing ICP-MS equipped with 9 Faraday collectors (ThermoFinnigan, Bremen, Germany) at Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology. The standard solutions were introduced to the plasma ion source as dilute (2%) nitric acid solutions via an Apex Omega desolvating nebulizer system (Elemental Scientific Inc., Omaha, USA) using only argon as a sweep gas. The desolvating nebulizer system can enhance iron signal for about 20 times compared to normal spray chamber, but cannot decrease interfering signals effectively (40Ar16O > 50V). Thus, iron and interfering signals were separated by medium resolution setting of NEPTUNE Plus of which resolving power is about 4000. To reduce pulsing which may reflect droplets of solution in the desolvating chamber, uptake rate was decreased from 100-160 ul/min to 40-60 ul/min. Although this reduction reduced sensitively, a 56Fe ion signal of ca. 300 V/ppm was still routinely obtained. In this presentation, we will exhibit details of iron isotope measurement, including sample preparation, 54Fe-57Fe double spike, data reduction and mass spectrometry.