J-GLOBAL ID:200904006403188775  Research Project code:0450021649 Update date:Jan. 19, 2004

Development of high accuracy lead isotope analysis method of ultra micro samples using surface ionization type mass spectrometer (TIMS)

Study period:2002 - 2002
Research overview:
Lead contains four stable isotopes of 204, 206, 207 and 208 and except for 204 they are isotopes of radioactive origin so that correction of mass fractionation caused during mass analysis is difficult. Therefore, in the analysis of lead isotopes high precision and high accuracy analysis such as in strontium or neodymium was difficult. Therefore, in this study, increase in the ionization efficiency of lead and stability in TIMS as well as improvement in the isolation method by ion exchange method was attained by using silicate and phosphate mixture as ionization activator. Same or better analytical precision was attained with less than 1ng of lead by this method compared with conventional analytical method that used 100ng of lead. Further, by applying 'Double-spike method', mass fractionation in TIMS could be corrected exactly to enable high accuracy isotope lead with ultra micro mass of lead. The analytical method developed here must contribute to the analysis of the ultra micro samples collected by MUSES-C.

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