提高热电离质谱灵敏度和防污染技术研究  

A TECHNIQUE OF ENHANCED SENSITIVITY AND OVERCOME RADIOACTIVE CONTAMINATION IN THERMAL IONIZATION MASS SPECTROMETRY

作　　者：邓中国[1] 魏子章[1] 

机构地区：[1]中国原子能科学研究院放射化学研究所,北京102413

出　　处：《原子能科学技术》1999年第6期553-557,共5页Atomic Energy Science and Technology

基　　金：核工业科学基金

摘　　要：先用氯化铵体系或硝酸体系电镀液将铀或钚样品电镀在单铼带上，再用氯铂酸体系或碱性体系电镀液电镀铂覆盖层。样品原子以热扩散方式从铂覆盖层渗透出而电离，样品物质不脱落，不污染仪器和环境。样品消耗少，电离效率高，１００ ｎｇ 铀、５０ ｎｇ 钚可获得约２×１０－ １４ Ａ离子流。同位素比值测量的不确定度为０．２ ％ ～０．３ ％ 。In order to overcome the radioactive contamination and enhance the sensitivity of thermal ionization mass spectrometry, some quantities of uranium of plutonim are electroplated on the single rhenium filament, then a thin layer of platium is overlaied on the filament. The sample atoms thermally diffuse through a platinum layer before they can evaporate as neutral atoms or as ions. Since thermal diffusion is generally a much slower process than direct evaporation and a platinum layer limits the prompt escape of neutral atoms, the filament can be operated at higher temperature, yielding higher ionization efficiency without rapid loss of the sample. The samples of uranium and plutonium are prepared for electrode position by adding 1.0 mol·L -1 HCl to dilute the uranium and plutonium concentrations to 0.1 g/L and 0.01 g/L, respectively. Three kinds of sample plating solutions are the mixtures of the ammonium chloride and chlorhydric acid; the ammonium chloride, chlorhydric acid and oxalic acid; the nitric acid, ammonia and oxalic acid, respectively. Two kinds of platinum solutions in the electrolyte are the chloroplatinic acid, chlorhydric acid and oxalic acid; the platinic sodium hydroxide, sodium hydroxide and oxalic acid, respectively. The ion currents observed for the 100 ng uranium or 50 ng plutonium are 2×10 -14 A during 40~60 min.

关 键 词：电镀 电镀覆盖层 放射性污染 热电离 质谱 核素 

分 类 号：O657.6[理学—分析化学] TQ153.19[理学—化学]