镁同位素质谱分析及分馏效应和电子倍增器歧视效应的修正方法  

MASS SPECTROMETRIC DETERMINATION OF MAGNESIUM ISOTOPIC RATIOS AND ITS CORRECTIONS FOR ELECTRON MULTIPLIER DISCRIMINATION AND MASS FRACTIONATION

作　　者：邓中国[1] 

机构地区：[1]中国原子能科学研究院

出　　处：《核化学与放射化学》1989年第2期118-123,共6页Journal of Nuclear and Radiochemistry

摘　　要：一、引言 镁是一种有实用价值的元素。用质谱计测定镁同位素比值的主要问题是:^(23)Na和^(27)Al杂质质谱峰拖尾的干扰;由同位素的质量差异和离子束流强度差异产生的质量相关偏差和离子束流强度相关偏差,即电子倍增器歧视效应;样品在蒸发和电离过程中由质量差异引起的分馏效应。镁同位素的质量差异和离子束流强度差异都较大,因而分馏效应和电子倍增器歧视效应必须进行修正。The mass spectrometric determination of magnesium isotopic ratios by the use of uranyl nitrate added to magnesium samples to act as a binding agent is reported. Prebaking empty filaments and preheating filaments with deposited magnesium samples on its surface in a vacuum are employed to reduce the Na signal from the rhenium-ribbon. Methods for correcting magnesium isotopic ratios for electron multiplier discrimination and mass fractionation are described in detail.The results of the determination of natural magnesium isotopic ratios are 26Mg/24Mg=0.12660(1±0.10%) and 26Mg/24Mg = 0.13938( 1±0.10%). The magnesium isotopic ratios of rich-26Mg-2 and rich-25Mg-l are 24Mg/26Mg = 0.003463 (1±0.2%), 25Mg/26Mg =0.001656 (1±0.2%) and 24Mg/25Mg =0 .006716 ( 1±0.2%), 26Mg/25Mg = 0.007264 (1±0.2%) respectively.

关 键 词：镁 同位素比值 质谱法 

分 类 号：O614.22[理学—无机化学]