铈同位素丰度的精确测定研究

Accurate Measurement of Cerium Isotopic Abundance

通过用高浓缩同位素１４２Ｃｅ和１４０Ｃｅ配制９种混合样品，精确测定质谱计的系统误差校正系数，来校正用该仪器测定的天然铈的同位素丰度比，从而建立了准确测定铈同位素丰度的质谱分析方法，用这种绝对质谱法测定的铈相对原子质量是１４０１１５７±００００８。

A series of nine standard solutions were prepared by blending highly enriched isotopes 142 Ce and 140 Ce,and employed for the determination of correction factor K for the Finnigan mass spectrometer MAT 261.The factor K was then used for the correction of natural Ce isotopic ratios in minerals and chemical reagents measured by this instrument. With this absolute mass_spectrometric method,the relative atomic mass of cerium was found to be 140 115 7±0 000 8.This value was accepted by the IUPAC Commission on Atomic Weights and Isotopic Abundances in 1995.